MSHA Proposed Rule
Verification of Underground Coal Mine Operators' Dust Control Plans
and
Compliance Sampling for Respirable Dust [07/07/2000]
[PDF Version]
Volume 65, Number 131, Page 42122-42185
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DEPARTMENT OF LABOR
Mine Safety and Health Administration
30 CFR Parts 70, 75 and 90
RIN 1219-AB14
Verification of Underground Coal Mine Operators' Dust Control
Plans and Compliance Sampling for Respirable Dust
AGENCY: Mine Safety and Health Administration (MSHA), Labor.
ACTION: Proposed rule; notice of hearings.
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SUMMARY: MSHA is proposing to revoke existing operator respirable dust
sampling procedures under parts 70 and 90, and to implement new
regulations that would require each underground coal mine operator to
have a verified mine ventilation plan. Under this proposal, MSHA would
verify the effectiveness of the mine ventilation plan for each
mechanized mining unit (MMU) in controlling respirable dust under
typical mining conditions. MSHA would collect full-shift respirable
dust samples, called ``verification samples,'' to demonstrate the
adequacy of the dust control parameters specified in the mine
ventilation plan in maintaining the concentration of respirable coal
mine and quartz dust at or below 2.0 mg/m\3\ and 100 <greek-m>g/m\3\,
respectively. The adequacy of these parameters would be demonstrated on
shifts during which the amount of the material produced is at or above
the ``verification production level'' (VPL) or the tenth highest
production level recorded in the most recent 30 production shifts.
[[Page 42123]]
The proposal would require mine operators to: First, set and
maintain the dust control parameters during MSHA verification sampling
at levels specified in the plan; second, maintain and make available to
MSHA records of the amount of material produced by each mechanized
mining unit during each production shift; and third, additional
information in mine ventilation plans. For longwall mine operations,
MSHA is also proposing to permit the use of either approved powered,
air-purifying respirators (PAPRs) or verifiable administrative controls
as a supplemental means of compliance if MSHA has determined that
further reduction in respirable dust levels cannot be achieved using
all feasible engineering or environmental controls appropriate for the
operational conditions involved. In addition, through this rule, MSHA
would conduct all compliance and abatement sampling under existing
parts 70 and 90.
DATES: Comments on the proposed rule should be submitted on or before
August 7, 2000.
We are also announcing that we will hold public hearings on the
proposed rule within 30 to 45 days of the publication of this rule. The
hearing dates, times and specific locations will be announced by a
separate document in the Federal Register. The rulemaking record will
remain open 7 days after the last public hearing.
ADDRESSES: You may use mail, facsimile (fax), or electronic mail to
send your comments to MSHA. Clearly identify comments as such and send
them--(1) By mail to: Carol J. Jones, Director, Office of Standards,
Regulations, and Variances, MSHA, 4015 Wilson Boulevard, Room 631,
Arlington, VA 22203;
(2) By fax to: MSHA, Office of Standards, Regulations, and
Variances, 703-235-5551; or
(3) By electronic mail to: comments@msha.gov. Written comments on
the information collection requirements may be submitted directly to
the Office of Information and Regulatory Affairs, OMB, New Executive
Office Building, 725 17th Street, NW, Washington, DC 20503, Attn: Desk
Officer for MSHA; and to Carol J. Jones, Director, Office of Standards,
Regulations, and Variances, MSHA 4015 Wilson Boulevard, Room 631,
Arlington, VA 22203; by facsimile to MSHA, at 703-235-5551; or by
electronic mail to comments@msha.gov.
The hearings will be held in the following locations: Prestonsburg,
Kentucky, (Jenny Wiley State Resort Park); Morgantown, West Virginia;
and Salt Lake City, Utah. The hearing dates, times and specific
locations will be announced by a separate document in the Federal
Register.
FOR FURTHER INFORMATION CONTACT: Carol J. Jones, Director, Office of
Standards, Regulations, and Variances, MSHA; 703-235-1910.
SUPPLEMENTARY INFORMATION:
I. Table of Contents
The preamble discusses: revocation of existing operator respirable
dust sampling requirements, revised procedures for adjusting the
respirable dust standard when quartz is present, the proposed rule,
engineering controls for respirable coal mine dust, dust control
parameters, supplemental controls, health effects of exposure to
respirable coal mine dust, degree and significance of the reduction in
the number of shifts during which there are overexposures, an analysis
of the technological and economical feasibility of this proposed rule,
and regulatory impact and flexibility analyses.
The preamble discussion follows this outline:
I. Table of Contents
II. Background
A. Coal Mine Respirable Dust Task Group
B. Advisory Committee on the Elimination of Pneumoconiosis Among
Coal Mine Workers
III. General Discussion
A. Revocation of the Operator Dust Sampling Program
1. Pre-1980 Sampling Program
2. Post-1980 Sampling Program
3. Issues Affecting the Credibility of Operator Compliance
Sampling
4. Proposed Reforms to the Respirable Dust Monitoring Program
a. Bimonthly Sampling
b. Abatement Sampling
c. Advantages of MSHA Compliance Sampling Over Existing Program
B. Revised Procedures for Setting the Applicable Dust Standard
When Quartz is Present
1. Current Procedures
2. Proposed Revised Procedures
3. Validity of Averaging Percentages
C. Respirable Dust Control Program for Underground Coal Mines
1. Evaluating and Approving Plan Requirements for Respirable
Dust Control
2. Compliance with Plan Requirements for Respirable Dust Control
3. Monitoring Effectiveness of Plan Requirements for Respirable
Dust Control
(a) Monitoring by Mine Operators
(b) Monitoring by MSHA
4. Proposed Procedures for Evaluating, Approving, and Monitoring
Plan Requirements
D. Hierarchy of Dust Controls
1. Selection of Respirators: Loose-Fitting PAPRs
2. Protection Factor for Loose-fitting Powered, Air-Purifying
Respirators
E. Guidelines for Determining What is a Feasible Dust Control
F. Application of Continuous Monitoring Technology to Prevent
Overexposure on Individual Shifts
IV. Discussion of Proposed Rule
A. Summary
B. Section-by-Section Discussion
V. Health Effects
A. Introduction
B. Hazard Identification
1. Agent: Coal
2. Physical State: Coal Mine Dust
3. Biological Action: Respirable Coal Mine Dust
C. Health Effects of Respirable Coal Mine Dust
1. Description of Major Health Effects
a. Simple Coal Workers' Pneumoconiosis (CWP) and Progressive
Massive Fibrosis (PMF)
b. Other Health Effects
2. Toxicological Literature
3. Epidemiological Literature
a. Simple Coal Workers' Pneumoconiosis (CWP) and Progressive
Massive Fibrosis (PMF)
b. Other Health Effects
VI. Quantitative Risk Assessment
VII. Significance of Risk
VIII. Feasibility Issues
A. Technological Feasibility
B. Economic Feasibility
IX. Regulatory Impact Analysis
A. Costs and Benefits: Executive Order 12866
1. Compliance Costs
2. Benefits
B. Regulatory Flexibility Certification and Initial Regulatory
Flexibility Analysis
X. Other Statutory Requirements
A. Plain Language
B. Unfunded Mandates Reform Act of 1995
C. Paperwork Reduction Act of 1995
D. National Environmental Protection Act
E. Executive Order 12630 (Governmental Actions and Interference
with Constitutionally Protected Property Rights)
F. Executive Order 12988 (Civil Justice)
G. Executive Order 13045 (Protection of Children from
Environmental Health Risks and Safety Risks)
H. Executive Order 13084 (Consultation and Coordination with
Indian Tribal Governments)
I. Executive Order 13132 (Federalism)
XI. Public Hearings
Appendix A. Derivation of the Critical Values
Appendix B. References
XII. Regulatory Text
II. Background
Maintaining a work environment free of excessive levels of
respirable coal mine dust and quartz dust (respirable dust) is
essential for long-term health protection. Through the joint
promulgation of the single, full-shift sample and plan verification
proposals, miners would be further protected from the debilitating
effects of occupational
[[Page 42124]]
respiratory disease by limiting their exposures to respirable coal mine
dust to no more than the applicable standard on each shift.\1\
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\1\ For details, see Quantitative Risk Assessment and
Significance of Risk Sections.
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Section 202(b)(2) of the Federal Mine Safety and Health Act of 1977
(Mine Act) requires each operator to continuously maintain the average
concentration of respirable dust in the mine atmosphere, during each
shift to which each miner in the active workings of such mine is
exposed, at or below 2.0 milligrams of respirable dust per cubic meter
of air (mg/m\3\). Under current MSHA regulations, when coal mine dust
contains more than five percent quartz, the respirable coal mine dust
standard is further reduced, by means of a formula. Although MSHA does
not currently enforce a separate standard for respirable quartz dust,
the formula (10 divided by the percentage quartz) used to establish an
applicable dust standard, in effect, limits quartz concentrations to
100 <greek-m>g/m\3\.
Consistent with the Mine Act and MSHA regulations, the primary
focus of the federal respirable dust program is on controlling the
concentrations of respirable dust in the work environment where miners
work or travel through the application of feasible environmental or
engineering control measures. Engineering or environmental control of
respirable dust in the mine environment is the ultimate dust-control
technique and the principal method for protecting miners' health. These
include all methods that control respirable dust levels in the air that
a miner breathes by either reducing dust generation, or by suppressing,
diluting, capturing or diverting the dust that is being generated by
the mining process. Under the Mine Act, the mine operator has primary
responsibility for implementing a program to control respirable dust so
that all miners work in an environment free of excessive levels of
respirable dust. For full compliance, mine operators must develop,
implement, and maintain effective engineering or environmental control
measures, and evaluate them at regular intervals to assure that they
function as intended. These control measures or ``dust control
parameters,'' are specified in the dust control portion of the
operator's mine ventilation plan currently required under Sec. 75.370.
Mine ventilation plans are a long-recognized means of addressing
health issues that are mine specific and for achieving work
environments that are free of excessive concentrations of respirable
dust. Currently, section 75.370 requires each operator of an
underground coal mine to develop and follow a ventilation plan that is
designed to control methane and respirable dust in the mine. The plan
must be suitable to the conditions and mining systems employed at the
mine. Although ventilation plans must be designed to control respirable
dust, there is no requirement that the plan's effectiveness be
verified.
The dust control portion of the mine ventilation plan is a key
element of the operator's strategy to control respirable dust in the
working environment of each mechanized mining unit (MMU) during each
shift. Section 70.2 defines an MMU to mean ``a unit of mining equipment
including hand loading equipment used for the production of material.''
The plans provide a description of specific engineering control
measures in use. The plans also contain procedures for maintenance of
specific dust control equipment, such as scrubbers, dust collectors on
roof bolters, and spray nozzles, or for the replacement of cutting
picks to minimize dust generation. Once approved by the District
Manager, the dust control parameters must be employed on a continuous
basis. By monitoring the parameters, one can be assured that respirable
dust levels are being adequately controlled without needing to rely on
repeated dust sample analyses.
Implementing dust control parameters, which have been determined
effective under typical mining conditions, and maintaining these
controls in proper working order provides reasonable assurance that no
miner will be overexposed. Because technology that continuously
monitors respirable dust and displays dust concentrations in real-time
is not currently used in underground coal mines, adhering to effective
ventilation plans is the only practical means of reasonably assuring,
on a continuous basis, that miners are not overexposed. In 1996, MSHA
implemented revised ventilation standards which, among other
provisions, required an on-shift examination of the dust control
parameters before coal production begins on each MMU. Based on the
recommendations of the MSHA Task Group (MSHA, 1992), this requirement
is intended to focus attention on the need for properly functioning
dust controls before production begins. On-shift examinations of dust
control parameters under existing Sec. 75.362 are important for an
effective respirable dust control strategy.
Recent advances in technology may make it feasible to continuously
monitor certain parameters such as, air quantity and velocity, and
spray water flow rate and pressure (Spencer, et al. 1996). Section
75.362 encourages the use of such monitors as it would eliminate the
need for periodic physical measurements of some dust controls to verify
if they are operating properly. Although current technology allows for
real-time data on the performance, the condition of key dust control
parameters, and for immediate modification of controls, MSHA is not
aware of its use by any operator.
Since establishment of the first comprehensive dust standards in
1969, the implementation of ventilation plans by mine operators and
their enforcement by MSHA has had a significant impact on control of
dust levels in underground coal mines. For example, based on federal
mine inspector sampling results, the average dust concentration in the
environment of a continuous miner operator (occupation code--036) has
been reduced by 86 percent over the past 30 years, from 7.7 mg/m\3\ to
approximately 1.1 mg/m\3\. This accounts for the significant decline in
the percentage of operator continuous miner designated occupation (DO)
samples exceeding 2.0 mg/m\3\, from 49 percent (over 32,000 samples/
shifts) in 1971, to 10 percent (over 2,500 samples/shifts) in 1999.
Analysis of all valid operator DO samples indicates that in 1971, the
2.0 mg/m\3\-dust standard was exceeded on 53,463 (44 percent) of the
122,404 shifts sampled, compared to 3,002 (10 percent) of the 28,727
shifts sampled in 1999 (MSHA, DO Samples by Calendar Year, 1999).
Despite this progress, MSHA has found evidence that a significant
number of overexposures still occur on the shifts sampled during which
the approved dust control parameters are operating at or above approved
levels. This evidence suggests that it is highly probable that some
miners are overexposed to respirable dust on shifts not sampled by
either the operator or by MSHA. In addition, recent medical
surveillance data suggests that miners continue to be at risk of
developing simple coal workers' pneumoconiosis (CWP), progressive
massive fibrosis (PMF) and silicosis (Elam, April 1999).
Certain aspects of the current respirable dust program limit MSHA's
ability to assure the adequacy of the dust control parameters under
typical mining conditions according to two expert panels which reviewed
the federal program designed to prevent pneumoconiosis among coal
miners. Both the Coal Mine Respirable Dust Task Group, an interagency
task group
[[Page 42125]]
established in 1991 by the Assistant Secretary for Mine Safety and
Health, and the Advisory Committee on the Elimination of Pneumoconiosis
Among Coal Mine Workers, established in 1995 by the Secretary of Labor,
considered all aspects of the respirable coal mine dust control program
and made recommendations for improvement.
A. Coal Mine Respirable Dust Task Group
In response to concerns about the Federal coal mine dust program
(MSHA, 1992), MSHA's Coal Mine Respirable Dust Task Group (the Task
Group) undertook an extensive review of the program to control
respirable coal mine dust and made recommendations to improve the
program in 1991. As part of that review, MSHA developed a special
respirable dust ``spot inspection program'' (SIP). This program was
designed to provide the Agency and the Task Group with information on
the dust levels to which underground miners are typically exposed.
Among other recommendations, the Task Group recommended that MSHA
require mine ventilation plans to be effective under typical mining
conditions.
The Task Group found that MSHA's current program did not promote
the development and implementation of quality plans. Based on its
review of a representative number of dust control plans, the Task Group
found that some plans lacked specificity or did not include all the
dust control parameters actually used. For example, the plans for three
major underground coal mines listed the air quantity, the primary means
of controlling concentrations of respirable coal mine dust, to be
18,000 cubic feet per minute (cfm) in the mining section. The actual
quantities measured by MSHA inspectors at these mines during the SIP
varied from 40,000 cfm to over 120,000 cfm.
Based on a review of MSHA Form 2000-86 (Revised), Respirable Dust
Sampling and Monitoring Data, similar differences were found between
air quantity specified in approved ventilation plans and the levels
observed at a number of longwall MMUs inspected in 1999. For example,
20 of the 47 longwall MMUs were using significantly more air than
specified in the ventilation plan (MSHA, September 1999). Under these
circumstances, it would be impossible to assess whether the air volume
specified in the plan was adequate to maintain dust concentrations at
or below the applicable dust standard. It should be noted that air
volume quantities, air velocities, water spray pressures, etc.,
specified in the plan are considered to be a minimum and MSHA
encourages mine operators to exceed their plan parameters, but only
after the levels specified in the plan have been shown to be effective
under the conditions in effect during sampling. In addition, a lack of
specificity in some plans made it difficult for MSHA inspectors to
determine whether the operator was complying with the approved plan.
Although several plans indicated that the mining equipment was to be
provided with water sprays, the plan did not specify the location of
the sprays or the water pressure at the spray nozzle.
The Task Group determined that the use of minimum production levels
for evaluating the effectiveness of dust control parameters can result
in marginal or inadequate plans. A more detailed discussion of the
impact of production on the quality of dust control parameters
specified in mine ventilation plans is provided later in this document
(in sections III.C.1. and IV.B.). Currently, MSHA relies on information
provided by the operator to determine at what production level the plan
should be evaluated. No production records are required for each MMU.
Although operators must submit production data on a quarterly basis,
the data is compiled for the entire mine. In addition, these quarterly
reports provide information on the amount of clean coal produced, which
are much lower than the tonnage of total material produced, and are not
useful for establishing what constitutes a ``normal production shifts''
for sampling purposes.
A follow-up survey conducted by MSHA in 1994 found that 43 percent
or 539 of the 1,245 producing MMUs, worked at least a 9-hour shift. The
Task Group also concluded that current regulations limiting the
duration of sampling to eight hours do not provide for adequate
assessment of respirable dust exposure during nontraditional shifts of
more than eight hours.
Implementation of the Task Group recommendations would have
required regulatory change. The effort to implement these changes was
suspended pending the recommendations of Advisory Committee on the
Elimination of Pneumoconiosis Among Coal Mine Workers, which was
convened in 1995.
B. Advisory Committee on the Elimination of Pneumoconiosis Among Coal
Mine Workers
On January 31, 1995, the Secretary of Labor established the
Advisory Committee on the Elimination of Pneumoconiosis Among Coal Mine
Workers (the Advisory Committee). The Advisory Committee was chartered
to ``make recommendations for improving the program to control
respirable coal mine dust in underground and surface mines in the
United States.'' The Advisory Committee identified and addressed many
of the same issues considered by the Task Group. Findings and consensus
recommendations were developed for each issue (MSHA, 1996). The
Advisory Committee concluded that the dust control portion of the mine
ventilation plan is the key element of an operator's strategy to
control respirable dust in the work environment. They concluded that
the initial evaluation, approval, in-mine verification and monitoring
to demonstrate the effectiveness of the operator's proposed dust
control plan is critical for the protection of miners from lung
disease. Also, believing that the credibility of the current system of
mine operator sampling to monitor compliance with exposure limits has
been severely compromised, the Advisory Committee concluded that
restoration of miner and mine operator confidence in the respirable
coal mine dust sampling program should be one of MSHA's highest
priorities. Accordingly, there was unanimous agreement that in order to
restore confidence in the program MSHA should take full responsibility
for all compliance sampling currently being carried out by mine
operators under 30 CFR parts 70 and 90.
The November 1996 Advisory Committee Report recommended numerous
improvements for the federal program to protect miners from simple CWP,
PMF, and silicosis. Of these, the following have been incorporated in
this proposal:
1. MSHA should take full responsibility for all compliance sampling
at a level which assures representative samples of respirable dust
exposures under usual conditions of work without adversely impacting
the remainder of the Agency's resources and responsibilities.
2. MSHA should, in consultation with the operator, perform
scheduled independent dust monitoring to verify the operator's plan.
3. MSHA should redefine the range of production levels which must
be maintained during sampling to verify the plan. The value should be
sufficiently close to maximum anticipated production level in order to
reasonably assure that the plan would be effective under typical
operations.
4. MSHA should review compliance and production records to
determine when there is a need for plan verification and modification.
[[Page 42126]]
5. MSHA should require that the results and monitoring of dust
control parameters and production be recorded in order to correlate
dust control parameters with dust measurements.
This proposal is intended to eliminate overexposures on individual
shifts and to restore the confidence of miners and mine operators in
the respirable coal mine dust sampling program by addressing the
shortcomings identified by the Task Group and the Advisory Committee in
the current respirable coal mine dust program. The proposal would
revoke the operator dust sampling programs under 30 CFR parts 70 and 90
and require the implementation of mine ventilation plans demonstrated
to be effective in maintaining respirable dust at or below the
applicable standard on each shift. These ventilation plans would be
verified by MSHA using single, full-shift respirable dust samples. The
plans' effectiveness would be monitored on a regular basis by the use
of inspector single, full-shift samples. The proposed rule regarding
the use of single, full-shift measurements of respirable coal mine dust
to determine average concentration is also published in today's Federal
Register.
MSHA recognizes that the Secretary of Labor's Advisory Committee on
the Elimination of Pneumoconiosis Among Coal Workers made several
recommendations that also impact on surface coal mine workers. These
surface coal mine issues will be addressed by the agency in a separate
rulemaking which is currently underway. The scope of that rulemaking
will include many of the issues that are addressed in this underground
rule including requirements for duct control plans, verification of
dust control plans prior to approval, on shift examination of dust
control measures, and the elimination of operator sampling for
compliance purposes.
III. General Discussion
This section describes the current respirable coal mine dust
program and the role of mine ventilation plans in safeguarding the
health of miners. Specifically, this section details:
(1) The reasoning behind MSHA's decision to revoke the operator
dust sampling programs under 30 CFR parts 70 and 90 and to take full
responsibility for all compliance sampling;
(2) The proposed procedures for arriving at an average quartz
percentage that is used to establish an applicable dust standard under
Secs. 70.101 and 90.101;
(3) The existing means for evaluating the effectiveness of dust
control parameters stipulated in mine ventilation plans;
(4) The plan approval process;
(5) Methods of assuring compliance with plan requirements; and
(6) MSHA's efforts to monitor plan effectiveness on a regular
basis.
There is also a detailed discussion of the hierarchy of dust controls
and the continued need for mine ventilation plans to specify dust
control parameters in order to preserve the primacy of engineering
controls. Finally, as a possible alternative to plan verification, we
have included a discussion and a request for comments on the
application of personal continuous monitoring technology which is, or
may become available, to prevent overexposure on individual shifts.
A. Revocation of the Operator Dust Sampling Program
Under the Federal Coal Mine Health and Safety Act of 1969 (Coal
Act) coal mine operators were required to take accurate dust samples at
periodic intervals to measure the amount of respirable dust in the mine
atmosphere where miners work or travel. The Coal Act also required that
citations be issued whenever respirable dust samples collected either
by an operator or by federal mine inspectors showed noncompliance with
the applicable dust standard. The Coal Act was amended in 1977 (Mine
Act), but the respirable dust provisions remained essentially
unchanged.
1. Pre-1980 Sampling Program
In 1970, federal regulations were issued that established the first
comprehensive coal mine operator dust sampling program. Those
regulations required the environment of the occupation on a working
section, or MMU, exposed to the highest respirable dust concentration
to be sampled--the ``high risk'' occupation concept. All other miners
working in the MMU in less risky occupations were assumed to be
protected from excessive concentrations of respirable coal mine dust if
the high risk occupation was in compliance. Under the program, each
operator was required to initially collect and submit ten valid
respirable dust samples to determine the average dust concentration
(across ten production shifts). If analysis showed the average dust
concentration to be within the applicable dust standard, the operator
was required to submit only five valid samples a month. If compliance
continued to be demonstrated, the operator was required to submit only
five valid samples every other month. The initial, monthly, and
bimonthly sampling cycles were referred to as the ``original,''
``standard,'' and ``alternative'' sampling cycles, respectively. When
the average dust concentrations exceeded the standard, the operator
reverted back to the standard sampling cycle.
Additionally, each working miner was sampled individually every 120
or 180 days, depending on the miner's work assignment, or every 90 days
for each miner (now referred to as a part 90 miner) who had a positive
chest x-ray for coal workers' pneumoconiosis (CWP) and who elected to
exercise the option of transferring to a less dusty area. However,
except for the part 90 miner results, these early individual sample
results were not used for enforcement, but were forwarded to the
National Institute for Occupational Safety and Health (NIOSH) to
develop a comprehensive exposure data base for research concerning
black lung disease. Each sample was accompanied by a completed mine
data card that included, among other things, the occupation and social
security number of the sampled miner. This information was also
included in the Agency's computer print-out of sampling results that
was sent to mine operators.
2. Post-1980 Sampling Program
In 1980, following hearings held throughout the coal fields (in
1977 and 1978), regulations governing operator sampling were
substantially revised by reducing the operator sampling burden, to
simplify the sampling process, and to enhance the overall quality of
the sampling program. The result was to replace the various sampling
cycles with a bimonthly sampling cycle and to eliminate the requirement
that each working miner be sampled. These are the regulations that
currently govern the mine operator dust sampling program. Like the 1970
rules, the current regulations continue to rely on sampling the
environment of the DO in the MMU that is exposed to the greatest
concentration of respirable coal mine dust, but reduced the number of
shifts required to be sampled from ten to five.
Other changes included replacing the requirement that each working
miner be sampled individually with the bimonthly collection of one
sample from each ``designated area'' (DA) to measure the dust
concentrations associated with dust-generating sources in the active
workings of the mine, such as along haulage ways, at underground
crushers, or at transfer points. These locations are strategically
selected so that the environment where miners normally work or travel
is monitored for compliance with the applicable dust
[[Page 42127]]
standard. The operator's approved ventilation plan identifies the
specific locations where DA samples are required to be collected and
the dust control measures used at these locations. Another change was
to increase the frequency of sampling part 90 miners from every 90 days
to one sample every 60 days.
The revised regulations also eliminated the reporting of personal
identifiers on the dust data card due to miner concerns that the data
may be used by mine operators to characterize the exposure of an
individual miner in future black lung claims. It also provided for
sampling equipment to be properly maintained and calibrated, and
examined during the shift. Additionally, operators' were required to
demonstrate a certain level of competence by passing a test
administered by MSHA. Since proper use of sampling equipment is
essential to the integrity of the sampling process, the certification
requirement was intended to provide reasonable assurance that the
person conducting sampling was competent to perform the task. After
samples have been collected, certified persons are required to properly
fill out the dust data card that accompanies each filter cassette.
These samples must then be transmitted unaltered to MSHA within 24
hours after the end of each sampling shift, to expedite compliance
determinations and minimize periods of miner overexposure.
While not specified in the regulations, operators are permitted by
practice to note on the dust data card any reason why they believe the
sample(s) transmitted are not valid and should not be used by MSHA to
determine compliance. Generally, such samples are voided by MSHA and
the operator is required to submit a substitute sample within that
bimonthly sampling period.
MSHA may also determine that an operator sample is invalid for many
of the same reasons. MSHA may also void operator samples for technical
and administrative reasons, such as samples submitted in excess of the
number required, or DO samples if they were not taken during a ``normal
production shift.'' ``Normal production shift'' is defined in existing
Secs. 70.2(k)(1), 70.207(a) and (d) as a ``production shift during
which the amount of material produced * * * is at least 50 percent of
the average production for the last set of five valid samples * * *''
After MSHA has processed the samples, the operator is provided with
a report of the sample results, which must be posted on the mine
bulletin board for a period of 31 days to provide miners ready access
to current information on respirable dust conditions in the mine.
Operators are also required to report to MSHA in writing any change in
the operating status of the mine, mining unit, or designated area that
affects the sampling requirements, within three working days after the
change occurs.
An operator who is found to be in violation of the reduced dust
standard is issued a citation and must take steps to reduce the dust
levels. After corrections have been made, the operator must collect
five additional samples within a time period specified by MSHA to
demonstrate compliance.
During the development of the 1980 regulations for operator
sampling requirements, we received comments that indicated a lack of
confidence in our reliance on operator samples for enforcement
purposes. In response to these concerns, MSHA published a proposed
regulation in 1980 that would have provided miners' representatives the
right to observe each phase of the operator dust sampling process with
no loss in pay. The proposal intended to promote better cooperation
between mine operators and miners in order to improve the effectiveness
of the program. In 1985, the Agency decided not to finalize regulations
to provide miners' representatives the right to observe operator
sampling, stating that compliance with the 1980 revisions to the
sampling program had resulted in greater confidence in the overall dust
program.
3. Issues Affecting the Credibility of Operator Compliance Sampling
As noted earlier in this proposal, there is general agreement that
significant efforts have been made during the past 30 years to reduce
dust levels in our Nation's mines. While most mine operators have
conscientiously attempted to sample miners' exposure to respirable coal
mine dust as required by regulation, because of the actions of some,
the operator sampling program continues to be plagued by allegations of
fraudulent sampling practices. Despite MSHA's efforts to improve the
quality of the operator dust sampling program and to vigorously
investigate such allegations and prosecute violators, sampling
irregularities continue to be documented involving the physical
alteration of the weight of dust collected on the filter, or the
collection of samples in low-dust areas of the mine or even outside of
the mine.
The Advisory Committee found that during the 10 years prior to the
publication of their report, serious questions had been raised
regarding the representativeness of respirable dust levels measured by
mine operators, the handling of filter cassettes, and the changing of
work assignments and/or working conditions during sample collection.
The credibility of the operator sampling program was questioned by
almost all the representatives of miners who testified before the
Advisory Committee. Since 1990, more than 160 mine operators, agents
and contractors have pled or been found guilty of submitting fraudulent
samples to MSHA. These disclosures correspond with the concerns
expressed by critics of the operator sampling program.
Detailed reviews of the respirable dust program by the Task Group
and the Advisory Committee identified aspects of the current program
that have the potential to negatively affect validity of sampling
results which could impact miner health protection and, consequently,
its credibility in the minds of the very people the program was
designed to protect, the miner. For example, to effectively monitor the
mine environment where miners work or travel, it is essential that
respirable dust samples are ``representative,'' in that they reflect
typical dust conditions to which miners are exposed. The recurrent
pattern of disclosures of tampering with the sampling process has
highlighted the vulnerability of the current monitoring system to the
submission of unrepresentative samples. For example, during the period
1980 to 1990, over 137,000 of the 750,000, or approximately 18 percent
of the operator DO samples showed extremely low concentrations (less
than or equal to 0.1 mg/m\3\), compared to 10 percent for the MSHA
samples. Since 1990, 14 percent of the operator DO samples and 3
percent of the MSHA samples were equal to 0.1 mg/m\3\.
The fact that sampling is controlled by the mine operator also
allows the operator to determine when and under what conditions samples
will be collected during all current bimonthly and abatement sampling.
This permits the operator to conduct sampling during those periods in
the mining cycle when conditions are anticipated to result in lower
dust levels in the mine environment. For example, the operator may
choose to sample during periods when the volume of air on the MMU is
greatest or when ventilation controls are operating at optimum
efficiently. Accordingly, these sample results may not be
representative of typical exposure levels. Other aspects of the
monitoring system that may allow the submission of unrepresentative
samples were reported by the Task Group in its report of
[[Page 42128]]
findings. Because some operators do not sample every bimonthly period
or fail to submit the required number of bimonthly samples, miners may
be potentially exposed to excessive levels of respirable dust.
4. Proposed Reforms to the Respirable Dust Monitoring Program
Believing that one of MSHA's highest priorities must be to restore
the confidence of miners and mine operators in the respirable coal mine
dust sampling program, one of the Advisory Committee's key
recommendations was that MSHA take full responsibility for all
compliance sampling at a level which assures representative samples of
respirable dust exposure under usual conditions of work. It also
recommended that compliance sampling should be carried out at a number
and frequency at least at the level required of operators and MSHA.
Accordingly, MSHA is proposing to revoke the operator dust sampling
programs under 30 CFR parts 70 and 90 and to take full responsibility
for all compliance sampling (i.e., bimonthly and abatement sampling),
in a manner that it believes will be more protective than the current
operator sampling program. MSHA intends to monitor miners' dust
exposure and compliance with the dust control provisions of the
approved mine ventilation plan, or with the respirable dust control
plan for a part 90 miner at underground mines, in accordance with the
procedures and guidelines established in Chapter 1 of the Coal Mine
Health Inspection Procedures Handbook, as modified herein.
(a) Bimonthly Sampling
MSHA would collect a full-shift sample from the working environment
of at least five different occupations, if available, on each producing
MMU, instead of sampling only the DO for five consecutive shifts or on
shifts worked on five consecutive days as under the current bimonthly
sampling program. Proposed revised Sec. 70.2(j) defines full shift, for
purposes of bimonthly compliance sampling, as the entire work shift
including travel time but excluding any time in excess of 480 minutes.
A full-shift sample would also be collected from each DA located inby
the section dumping point (i.e., intake air and roof bolter DAs)
bimonthly, and from all other DAs once each year. All part 90 miners
would be sampled bimonthly as under the current program.
MSHA would issue a citation for noncompliance when a single, full-
shift measurement demonstrates, at a high level of confidence, that the
applicable dust standard is exceeded. Although MSHA would collect
multiple occupational samples from each MMU, we would issue only one
citation on a single shift on any one MMU unless more than one dust-
generating source was involved.
(b) Abatement Sampling
Under this proposal, MSHA would also assume responsibility for all
abatement sampling. As recommended by the Advisory Committee, MSHA
would utilize single, full-shift samples to demonstrate abatement.
Since the criteria under which the effectiveness of ventilation plans
are required to be verified are significantly more stringent than those
for bimonthly sampling, MSHA does not anticipate issuing many citations
to MMUs and sectional DAs. However, should an MMU be cited for
violation of the applicable dust standard, and a determination be made
by the inspector who was onsite that the dust control parameters are no
longer adequate for the present operating conditions, MSHA would
require the operator to revise the dust control portion of the mine
ventilation plan under proposed Sec. 70.219. MSHA would then verify the
effectiveness of the revised plan. Citations for violating the
applicable dust standard would not be based on verification sampling.
If on the other hand, a determination is made that a change in the
plan is not warranted, the operator would take corrective action to
prevent miners from being exposed on subsequent shifts. MSHA would then
sample the MMU, similarly to bimonthly compliance purposes described
previously in paragraph (a) of this section. All five of the
occupational samples taken on a single shift would have to be below the
applicable standard to demonstrate abatement. If any sample result
exceeds the applicable standard, but not at a sufficiently high level
of confidence to warrant a citation, then MSHA may sample additional
shifts or initiate the plan verification process.
We solicit comments on whether MSHA should require a higher level
of confidence that the applicable standards are being complied with
before abating a citation for excessive dust. Specifically, should
abatement determinations be based on the critical values specified in
Sec. 70.209? We also solicit comments on whether abatement sampling
should be conducted at or above the Verification Production Level (VPL)
as defined in Sec. 70.2(aa). Requiring that abatement be demonstrated
under more typical production conditions, as represented by the VPL,
would provide assurance that miners will continue to be protected on a
majority of the production shifts.
MSHA proposes to conduct abatement sampling involving non-MMU DAs
and part 90 miners in the same way as it conducts bimonthly sampling. A
violation would be abated if the result of an abatement sample was less
than the applicable standard. If sample results exceed the applicable
standard but not at a sufficiently high level of confidence to warrant
a citation, MSHA may collect additional single, full-shift samples.
As in the case of MMU abatement samples, we solicit comments on
whether MSHA should require a higher level of confidence that abatement
samples for non-MMU DAs and for part 90 miners demonstrate compliance
with the applicable standards before abating a citation for excessive
dust. Specifically, should abatement determinations be based on the
critical values specified in Sec. 70.209?
(c) Advantages of MSHA Compliance Sampling Over Existing Program
According to section 101(a)(9) of the Mine Act, no health standard
promulgated under this title shall reduce the protection afforded
miners by an existing mandatory health standard.
For the reasons listed below, MSHA believes that, through the joint
promulgation of this proposed rule and the proposed single, full-shift
sample rule, miners would be further protected from the debilitating
effects of occupational respiratory disease by limiting their exposures
to respirable coal mine dust and quartz dust on every shift.
<bullet> Providing and maintaining a work environment free of
excessive levels of respirable dust is essential for long-term health
protection. While monitoring of the work environment provides an
indication of how effective the existing dust control measures are,
monitoring alone does not control dust levels. Requiring mine operators
to implement and maintain dust control parameters which, for the first
time, have been determined effective under typical mining conditions,
will provide reasonable assurance that no miner will be overexposed on
individual shifts.
<bullet> Implementing single, full-shift sample determinations will
more likely detect excessive dust concentrations and thus protect
miners. Averaging samples taken on multiple shifts can mask
overexposures on individual shifts. Although MSHA would be sampling
fewer shifts, MSHA believes the proposed sampling methodology
[[Page 42129]]
would provide a more accurate representation of dust conditions to
which miners are exposed.
<bullet> Under the existing operator sampling program, only the DO
is sampled. Under the proposed program, MSHA would sample multiple
occupations on the same shift. This would provide a more comprehensive
assessment of dust conditions to which miners are exposed.
<bullet> Since MSHA will be doing all the sampling, we will be able
to monitor the dust control parameters and work practices in effect
during sampling. This will enable MSHA to determine the effectiveness
of the operator dust control program.
<bullet> Unlike the current sampling program, which allows
operators control over when to sample and under what operating
conditions, MSHA's visits will be unannounced. As a result, all phases
of the mining cycle are likely to be sampled eventually (i.e.,
construction activity, longwall start-up, turning crosscuts, etc.), and
samples should be more representative of typical mining conditions.
<bullet> The miners' representative will have walkaround rights
during sampling, thereby increasing miners' confidence in the dust
sampling program.
B. Procedures for Setting the Applicable Dust Standard When Quartz is
Present
Section 202(b)(2) of the Mine Act and the implementing MSHA
regulations require each operator to continuously maintain the average
concentration of respirable dust in the mine atmosphere during each
shift to which each miner in the active workings of such mine is
exposed at or below 2.0 mg/m\3\. Under current MSHA regulations in
Secs. 70.101, and 90.101, the applicable coal mine dust standard is
lowered further, by means of a formula (10 divided by the percentage of
quartz) prescribed by Secretary of Health, Education, and Welfare in
1971, whenever the respirable coal mine dust in the mine atmosphere of
the active workings contains more than five percent quartz. \2\ This is
based on the recognition that the toxicity of coal mine dust increases
when higher levels of quartz are present. Consequently, as the quartz
content of respirable coal mine dust present in the mine atmosphere
increases over five percent, the applicable respirable coal mine dust
standard is correspondingly lowered. For example, if 10 percent quartz
was present, the mine operator would have to continuously maintain
respirable dust at or below 1.0 mg/m\3\.
---------------------------------------------------------------------------
\2\ The applicable dust standard for intake air in
Sec. 70.100(b) and for miners who have exercised rights under part
90 regulations in Sec. 90.100 is 1.0 mg/m\3\. Those standards are
also lowered if quartz exceeds 5 percent. However, no effect occurs
until the quartz content exceeds 10 percent.
---------------------------------------------------------------------------
The following provides an overview of MSHA's current and proposed
revised procedures for arriving at an average quartz percentage that is
used to establish an applicable dust standard.
1. Current Procedures
Until 1985, the applicable dust standard was adjusted based on the
percentage of quartz determined from a single, full-shift (8 hours or
less in duration) respirable dust sample taken by an MSHA inspector.
Since MSHA sampled less frequently than we currently do, a reduced
standard could remain in place anywhere from 12 to 24 months. During
that period the level of quartz could have either increased or
decreased significantly. As a result in December 1985, MSHA implemented
the procedures in effect. This program, for the first time, enabled
mine operators to participate voluntarily in the process of setting
reduced dust standards. These procedures are contained in Chapter 1 of
MSHA's Coal Mine Health Inspection Procedures Handbook.
The most significant program change involved the use of individual
quartz percentages determined from one MSHA and, under certain
conditions, up to two coal mine operator full-shift respirable dust
samples, referred to as ``optional samples,'' to arrive at an average
quartz percentage. It also provides for the automatic reevaluation of
work areas and occupations on a reduced dust standard every six months.
Under the existing system, if an MSHA sample contains more than
five percent quartz, an operator is afforded the opportunity to submit
an optional sample. Provided it has sufficient weight gain (0.45 mg),
the quartz content will be averaged with the MSHA sample when sample
results do not differ by more than <plus-minus> 2.0 percent, and the
standard set accordingly. If an operator fails to submit an optional
sample or it contains insufficient weight for analysis, the standard is
adjusted based on the MSHA sample alone. Operators are afforded the
ability to submit a second optional sample whenever sample results
differ by more than <plus-minus> 2.0 percent. All three results are
then used to compute the average quartz percentage.
Also, in November 1994, MSHA refined its analytical procedure
enabling us to analyze inspector low-mass respirable dust samples
(0.100 to 0.449 mg) for quartz. Only those samples containing 25
micrograms or more of quartz were used in the standard-setting process.
However, this change applied only to filters that were preweighed to
0.001 mg for use by MSHA enforcement personnel. It did not apply to
operator-submitted optional samples, which were collected with filters
preweighed to 0.01 mg, for which we required a minimum of 0.45 mg of
dust to be analyzed for quartz. The ability to accurately analyze
samples containing small amounts of dust reinforced MSHA's views about
the severity of quartz exposures in some coal mining operations.
A review of MSHA data for FY 1999 shows that of the 778 entities
(i.e., MMUs, DAs, designated work positions (DWPs), roof bolters, and
part 90 miners) (MSHA, Results of Quartz Sampling Operator Involvement,
1999) placed on an initial reduced standard as a result of an MSHA
sample containing more than five percent quartz, 753 (96 percent) of
the entities submitted an optional sample. One would expect the level
of participation to be high since failure to respond would result in
the setting of a lowered dust standard based on the result of the MSHA
sample, which first triggered the standard-setting process. Of the 753
entities submitting an optional sample, 231 were afforded the ability
to submit a second optional sample (Ibid.). Again, as expected, over 73
percent (170) of those 231 entities submitted a second optional sample,
probably because doing so could reduce the quartz average quartz
percentage used to establish the applicable dust standard. For
comparison, in FY 1992, 93 percent of the operators afforded the
opportunity submitted an optional first sample, and 82 percent of the
operators given the opportunity submitted a second optional sample.
However, as the following data show, operator participation tended
to decline significantly when operators were given the opportunity to
submit samples involving established entities on reduced standards. Of
the 1122 entities given the option to submit a sample, only 450 or 29
percent responded, compared to 96 percent for entities placed on an
initial reduced standard. In 1992, 32 percent of the operators elected
to participate.
2. Proposed Revised Procedures
Consistent with MSHA's decision to assume full responsibility for
compliance sampling, the Agency is also proposing to rely only on MSHA
samples as the basis for setting the applicable dust standard when
quartz is present. As discussed below, while the proposed scheme
reduces the burden and cost on mine operators to take and
[[Page 42130]]
submit optional samples, it does not diminish the protections afforded
operators under the current program. It continues to consider temporal
variability associated with quartz determinations by averaging three
MSHA samples collected on different shifts. MSHA recently published a
proposed ``Program Policy Letter (PPL) on Samples Used to Determine the
Respirable Dust Level When Quartz is Present'' for public comment [64
FR 65671, November 23, 1999] whereby the applicable dust standard would
be set based on the results of multiple MSHA samples. It proposes that
mine operator samples would no longer be used in combination with MSHA
samples to determine the average quartz percentage that is used to set
an applicable dust standard. In the proposed rule, MSHA is adopting the
sampling approach set out in the PPL. The proposed rule supercedes the
proposed PPL, and consequently, the proposed PPL is withdrawn.
We believe that results under the proposed process will be more
representative of the quartz level to which miners are exposed. Unlike
the current process, which may cause a standard to be set based on the
quartz content of a single MSHA sample, three valid MSHA samples would
be used to set a reduced standard under the proposed revised procedures
[64 FR 65671].\3\ Since MSHA is sampling underground mines bimonthly
and surface mines semi-annually, we will have no difficulty in
collecting the required number of samples to arrive at the average
quartz percentage. If initial sampling shows that miners may be exposed
to excessive levels of quartz, MSHA intends to sample at a greater
frequency to ensure that miners are being protected. This level of
sampling should also allay any operator concerns regarding the
collection of ``misleadingly high'' samples during atypical periods.
MSHA would also begin reporting quartz levels to the nearest tenth of a
percent. This is intended to be more protective for the miner than the
current truncation of results to a full percentage point.
---------------------------------------------------------------------------
\3\ Unlike MSHA's objective in compliance sampling, the
objective in measuring quartz content is to establish a reduced
standard that will apply to all shifts. This enables an operator to
design a ventilation plan that will be protective on every shift.
Therefore, it is appropriate to estimate the quartz content by
averaging quartz measurements obtained over an extended time period.
---------------------------------------------------------------------------
Under the proposed revised procedures, when an MSHA sample contains
more than five percent quartz, we would average the percent of quartz
present in three most recent MSHA respirable coal mine dust samples to
set the applicable dust standard. If an MMU, DA, DWP, or part 90 miner
is already on a reduced standard, a new applicable dust standard will
be established by averaging the results of the first two MSHA samples
taken under the proposed procedures with the quartz percentage
associated with the reduced standard in effect. If fewer than two MSHA
samples are taken, the existing reduced standard will continue to
remain in effect.
Assume an MMU is on a 1.0 mg/m\3\-standard (10 percent quartz). If
the first MSHA sample contains 7.2 percent of quartz, the existing
standard of 1.0 mg/m\3\ would continue to remain in effect. If,
however, the next sample contains 16.1 percent, the average quartz
percentage would be 11.1 percent [(10.0% + 7.2% + 16.1%) <divide> 3 =
11.1%], resulting in a 0.9 mg/m\3\<ls-thn-eq>-standard (10 <divide>
11.1% = 0.9 mg/m\3\). For MMUs, DAs, DWPs, or part 90 miners not on a
reduced standard, MSHA would collect and analyze three samples for
quartz to determine if a reduced standard was warranted.
Under the proposed procedures, if the newly-established standard is
lower than the one in effect, the new standard would become effective
seven days after the date of the notice informing the mine operator of
the change in the applicable dust standard. However, if it is higher
than the current standard, the newly-established dust standard would
become effective on the date of the notice.
As published elsewhere in today's Federal Register, MSHA is also
proposing to take enforcement actions on the basis of inspector single,
full-shift, respirable dust measurements. For entities on a reduced
standard, MSHA would delay any enforcement action until the sample is
analyzed for quartz. If an exposure measurement significantly exceeds
the existing standard and the quartz content of that sample would cause
the standard to be lowered below the existing reduced standard, the
operator would be cited for violation of the applicable standard
currently in effect. On the other hand, if the quartz content of the
sample would cause the dust standard and the corresponding citation
threshold value (CTV) to increase so that the single, full-shift
measurement would no longer indicate noncompliance, no citation would
be issued. This is illustrated by way of the following example.
For example, suppose that the MMU is on a 1.3-mg/m\3\ standard and
a single, full-shift measurement of 1.6 mg/m\3\ is obtained. Since this
measurement exceeds the applicable standard, the operator is in
violation of the standard. However, analysis of the DO sample shows
that the sample contained 6 percent quartz which, if used, would result
in a 1.7-mg/m\3\ standard. This indicates that the quartz level in the
environment of the DO has changed, suggesting that the current standard
may no longer be valid. Therefore, since the original measurement of
1.6 mg/m\3\ is less than the 1.7-mg/m\3\ standard that should have been
in effect on the shift sampled, a citation should not be issued.
Since MSHA samples are viewed to be more representative of the
respirable dust concentration to which miners are exposed, MSHA is
proposing to revise section 70.101 to clarify that the Secretary will
determine the quartz level by sampling. Operator samples may no longer
be submitted for determining the applicable standard. It is our belief
that the procedures being proposed for setting reduced standards should
be more protective for the miners than those in effect. The proposed
approach provides for stringent monitoring exposure to quartz which is
consistent with Advisory Committee's recommendation that MSHA increase
surveillance and reduce exposure to this serious health hazard.
As under the current program, if operating conditions should change
following establishment of a lowered dust standard that affect the
level of quartz in the working environment, mine operators or miners'
representatives will be able to request MSHA to conduct a quartz
reevaluation. In the absence of continuous monitoring, mine operators
should be cautious in preventing overexposures when abnormal conditions
(such as cutting rock to install an overcast or other frequent but
short-lived events involving cutting of rock) are encountered between
MSHA sampling visits.
3. Validity of Averaging Percentages
The average quartz percentage used to set the applicable dust
standard for a particular sampling location or area of a mine is
determined in accordance with accepted mathematical procedures for
arriving at an average value from a set of values (i.e., adding
together the individual quartz percentages and dividing by the number
of analyses that are in the set). MSHA believes that this is the most
appropriate method to use.
One commenter who responded to the PPL (op cit.) contended that
MSHA's approach of arriving at the average quartz percentage was
mathematically incorrect. This commenter recommended that, to more
accurately
[[Page 42131]]
reflect the true quartz concentration, the average quartz percentage be
calculated by dividing total mass of quartz in micrograms by the total
mass of dust collected (based on three samples in the example
submitted). In the commenter's example, the average percentage obtained
using MSHA's proposed averaging method was larger than that obtained
using the commenter's approach.
The following two scenarios in Table III-1 clearly demonstrate that
MSHA's averaging method does not always result in a larger average
quartz percentage value.
Table III-1.--For Two Scenarios, Using Alternate Methods, Percent of Quartz in Respirable Dust
----------------------------------------------------------------------------------------------------------------
Scenario I Scenario II
----------------------------------------------------------------------------------------------------------------
Dust mass SiO<INF>2</INF> mass % SiO<INF>2</INF> Dust mass SiO<INF>2</INF> mass % SiO<INF>2</INF>
----------------------------------------------------------------------------------------------------------------
1.7 0.136 8 1.7 0.17 10
1.0 0.04 4 1.0 0.08 8
2.5 0.3 12 2.5 0.15 6
----------------------------------------------------------------------------------------------------------------
MSHA's Method Average of % SiO<INF>2</INF> = 8 MSHA's Method Average of % SiO<INF>2</INF> = 8
----------------------------------------------------------------------------------------------------------------
Commenter's Commenter's
Method Sum (SiO<INF>2</INF> Mass) <divide> Sum (Dust Method Sum (SiO<INF>2</INF> Mass) <divide> Sum (Dust
Mass) = 9.2% Mass) = 7.7%
----------------------------------------------------------------------------------------------------------------
These examples show that for situations where MSHA would have
determined a quartz percentage of 8 percent, the commenter's method
would yield 9 percent in one case and 7 percent in the other.
C. Respirable Dust Control Program for Underground Coal Mines
The primary focus of the underground coal mine respirable dust
program is to limit the concentration of respirable dust to which
miners are exposed in the work environment. To ensure that miners are
not being exposed to excessive concentrations of respirable dust,
current regulations require mine operators to:
<bullet> Design a mine ventilation plan that effectively controls
respirable dust under typical mining conditions;
<bullet> Implement the plan's dust control parameters when approved
by MSHA before commencing production;
<bullet> Maintain the dust control parameters specified in the
approved plan and to monitor their function and operation through
required on-shift examinations; and
<bullet> Evaluate their effectiveness with bimonthly samples in
order to provide reasonable assurance that the dust control parameters
continue to function as intended.
To control dust in the work environment, existing Sec. 75.370
requires mine operators to develop and submit ventilation plans that
are designed to control methane and respirable dust in the mine to MSHA
for approval. Each plan must be suitable to the conditions and mining
system in use at the mine. These plans provide detailed requirements
for the protection of miners by specifying engineering controls. These
engineering controls may include:
<bullet> The quantity and the velocity of the air current used to
ventilate the MMU;
<bullet> The number, type, and location of water sprays;
<bullet> The pressure and quantity of water delivered by the
sprays; and
<bullet> Additional environmental controls, such as dust scrubbers
or devices which collect mine air and filter out dust particles.
Plans also contain procedures for maintenance of dust control
equipment used on the mining machine and roof bolter. Mine operators
frequently do not fully describe all dust controls in use at the mine.
If such information is not fully disclosed, it is impossible for MSHA
to fully enforce the plan provisions and to determine when the MMU is
out of compliance with the ventilation plan.
When an operator submits a proposed mine ventilation plan or
revision in accordance with Sec. 75.370, the MSHA district office
reviews it for completeness and adequacy. The District Manager will
approve the plan if it meets MSHA requirements, and he is confident
that the dust control parameters specified will have a reasonable
likelihood of maintaining dust concentrations within the allowable
limits. Most proposed plans or revisions are approved immediately, or
tentatively approved, based on engineering judgement, or experience, or
both, until they are assessed by MSHA inspector sampling or, to a
lesser extent and only under certain circumstances, by mine operator
bimonthly sampling. Generally, MSHA samples within 60 days of plan
approval. Current regulations prohibit a mine operator from initiating
any mining activity without an approved ventilation plan. MSHA allows
operators to commence mining by granting tentative approval. However,
plans may be implemented which are later determined to be inadequate
under typical mining conditions under the existing process.
1. Evaluating and Approving Plan Requirements for Respirable Dust
Control
Under the current program, the effectiveness of the plan's dust
control parameters is assessed through sampling of the DO and other
occupations associated with the MMU. Since there is no requirement for
verifying plan effectiveness, we have had to rely on samples that may
not be representative of dust concentrations to which miners are
exposed.
MSHA sampled annually at each underground mine until recently. The
Agency now samples bimonthly in each underground coal mine. This
increased sampling effort is part of MSHA's initiative to increase
confidence in the federal respirable dust program and to eliminate
simple CWP, PMF, and silicosis among coal miners. During sampling
inspections, we monitor compliance with the applicable dust standard,
measure the concentration of respirable quartz dust; and identify
occupations other than the DO that the mine operator should routinely
monitor because they are at risk of exposure to excessive
concentrations of respirable dust.
Under current inspection procedures, MSHA inspectors sample at
least five different occupations, if available, on each MMU on each
shift. Samples are normally taken under the mining conditions in effect
during sampling. In conjunction with this sampling, the MSHA inspector
checks and measures the dust control parameters early in the shift to
determine whether the ventilation plan is being followed. The inspector
records the findings, and all
[[Page 42132]]
the dust controls and work practices in use during sampling on MSHA
Form 2000-86 (Revised), Respirable Dust Sampling and Monitoring Data.
MSHA will issue a citation if the mine operator fails to follow any of
the dust control parameters specified in the plan. Normally, the
citation requires immediate corrective action to abate the violation.
This may involve, for example, unplugging some water sprays or
increasing the amount of ventilating air delivered to the MMU. At the
conclusion of the sampling shift for an MMU, the inspector determines
the total amount of material that was mined (in tons) during the shift.
If the average concentration of the samples taken in one shift is
less than, or equal to, the applicable standard, and the actual
production is at least 60 percent of the average production over the
last 30 production shifts, the MSHA inspector will normally terminate
sampling after the first day and will recommend that the plan
parameters be approved by the District Manager. This would occur even
if the samples were found to contain more than 5 percent of quartz.
Such a finding could result in MSHA lowering the dust standard below
that in effect at the MMU. Since 1985, MSHA has provided mine operators
the opportunity to participate in the process to establish a lower dust
standard based on the level of quartz. Mine operators can submit up to
two optional samples which are averaged with the MSHA sample to
determine the average percentage of quartz which is used to establish a
new dust standard for the MMU. MSHA published a proposed Program Policy
Letter for comment (64 FR 65671, November 23, 1999) whereby the
standard would be determined based solely on the results of multiple
MSHA samples. Under that proposal, mine operator samples would no
longer be used to calculate a reduced dust standard. Instead,
applicable dust standards will be set based solely on the results of
MSHA samples.
If the average concentration falls below the standard in effect,
but one or more samples exceed it, no decision is made regarding the
plan's effectiveness or regarding compliance with the applicable
standard. Instead, the inspector must collect additional samples on
subsequent production days or shifts to establish that the dust control
provisions of the ventilation plan are adequate.
To a lesser extent, if MSHA is unable to schedule a mine visit
within the period established by the individual district, the District
Manager may rely on the results of operator bimonthly sampling to
approve a plan. Generally, this occurs in the case where a plan is
upgraded with a change which has been established as effective. MSHA
does not routinely approve plans based on operator bimonthly sampling
because these samples may be collected during periods when production
is not reflective of typical production levels. The current program
permits the operator to submit samples which may not be representative
of normal dust conditions in the working environment. Under current
regulations, operator bimonthly samples will be considered valid,
unless voided by MSHA, when the MMU produces at least 50 percent of the
average level reported for the last set of five valid bimonthly
samples. Since a mine's ``normal production'' level for sampling
purposes and the typical production level may diverge greatly over the
course of several sampling periods, granting approval under these
conditions may not reflect the plan's effectiveness under more typical
mining conditions.
2. Compliance with Plan Requirements for Respirable Dust Control
Once MSHA determines that the dust control measures are adequate
and approves the mine ventilation plan, the specified dust control
parameters are to be employed on a continuous basis to safeguard the
health of miners. Since maintaining the approved dust control
parameters provides reasonable assurance that respirable dust can be
controlled, failure to comply with these requirements would defeat the
purpose of the mine ventilation plan and needlessly expose miners to
excessive concentrations of respirable dust. Section 75.362 requires
mine operators to perform an on-shift examination of the dust control
parameters before the MMU begins production in order to assure full
compliance. Any deficiencies must be corrected before production
begins.
Compliance with approved plan parameters is checked during MSHA's
routine sampling inspections: as part of six-month plan reviews, during
other non-sampling inspections or investigations, or in conjunction
with an ongoing sampling inspection.
3. Monitoring Effectiveness of Plan Requirements for Respirable Dust
Control
Because of the dynamic nature of mining, conditions can change
significantly in a short period of time. For example, an increase in
the concentration of respirable quartz dust will require the applicable
standard to be reduced below the level that was effective when the dust
control parameters were first evaluated. Such changes can directly
impact the effectiveness of the dust-control measures. It is important
to regularly monitor the adequacy of the approved dust control
requirements to ensure that they remain suitable for the current
conditions at the mine and to determine whether the plan should be
upgraded. Currently, both MSHA and the mine operator regularly monitor
the operator's dust control program. However, for MMUs the mine
operator is responsible for making sure that all provisions of the
ventilation plan are in effect on every shift.
(a) Monitoring by Mine Operators. Since 1980, the current
regulations have required mine operators to take five valid samples
from the DO in each MMU on a bimonthly basis and submit them to MSHA
for processing, to determine compliance with the applicable dust
standard. Section 70.207(e) identifies the DO for each method of
mining. These are collected either on consecutive normal production
shifts, or on production shifts worked on consecutive days, during
which the amount of material produced by the MMU is at least 50 percent
of the average production reported for the last bimonthly sampling
period. These samples must be collected portal-to-portal during the
entire shift or for 8 hours, whichever time is less.
Bimonthly samples have provided a periodic evaluation of the
quality of the air miners breathe. They also have provided some insight
into the effectiveness of the operator's dust control system on the
days in which the samples are taken. Mine operators may exceed their
minimum plan requirements once they have been approved as effective
under current evaluation criteria. Currently, there is no requirement
for mine operators to record the dust control measures in use as part
of the on-shift examination. Because there is no requirement for such
records, MSHA cannot assess the continued adequacy of the approved dust
control requirements unless the inspector observes the sampling
process.
Although the current operator sampling program may limit the
utility of bimonthly samples for plan approval purposes, they allow
MSHA to identify approved plans that may no longer be suitable to the
conditions at a mine. If multiple individual samples, or their average,
exceed the applicable dust standard after the required on-shift
examination has been conducted, the approved plan parameters may no
longer be effective and may need to be upgraded. If cited, the operator
must
[[Page 42133]]
take corrective action to lower the concentration of respirable dust to
within the permissible concentration as described in current
Sec. 70.201(d). The operator must demonstrate, through sampling, that
the underlying condition(s) which caused the violation has been
corrected. Since MSHA inspectors are not present to observe the
action(s) taken by the operator to abate the violation, the ventilation
plan is usually not amended to include the changes the operators make
to the parameters in order to abate the violation. However, if the
operator has a record of noncompliance and MSHA determines that the
approved plan parameters may no longer be adequate, MSHA will notify
the operator to submit an improved plan. Under current plan approval
procedures, if the operator fails to address MSHA's concerns after
receiving the second notification, MSHA will move to revoke the
operator's mine ventilation plan. If the plan is revoked, the mine must
not operate.
As discussed earlier, MSHA is proposing to revoke operators'
sampling program in underground mines and assume full responsibility
for all compliance sampling.
(b) Monitoring by MSHA. One of the objectives of MSHA's dust
sampling program is to verify that the controls specified in the
approved mine ventilation plan continue to control concentrations of
respirable dust under existing mining conditions. As part of this
program, the dust control parameters must be checked and measured early
in the shift to assure compliance with the approved plan. These checks
also verify that the operator is performing the required on-shift
examinations. Operators have the opportunity to adjust their dust
controls to reflect that which has been approved so the plan can be
evaluated. However, most operators choose not to make adjustments for a
number of reasons. While inspection procedures require the ventilation
plan to include the dust control measures in use during the evaluation,
most approved plans do not incorporate all the measures that were
actually in place during MSHA sampling. This makes it difficult for
MSHA to assess the continued adequacy of the approved dust control
parameters. Frequently, decisions must be based only on prior
experience or engineering judgment.
When an operator is cited based on MSHA samples, the inspector may
require the operator to describe what type of corrective action will be
taken. However, if a plan change is required, MSHA must follow similar
plan approval procedures. The operator must be notified in writing that
the plan is inadequate. In this case, MSHA has sample results and a
record of the actual parameters in place which can be used to document
the need for a plan change. Most plans which are revised simply
incorporate only those dust controls that were in use when MSHA
sampled.
MSHA reviews each mine ventilation plan every six months under
Sec. 75.370. The review includes: all plan revisions, respirable dust
inspection reports, citations for exceeding the applicable dust
standard, and comments from representatives of miners. When a
deficiency in the respirable dust control portion of the plan is found,
the MSHA inspector records comments on MSHA Form 2000-86. MSHA sends
these results to the mine operator along with an explanation of whether
the operator must make any changes, the reasons for the changes, and
the date for submitting a plan revision. MSHA will send a second
notification if the operator fails to respond. MSHA may revoke the
operator's mine ventilation plan if the operator does not comply.
4. Proposed Procedures for Evaluating, Approving, and Monitoring
Ventilation Plan Requirements
The dust control portion of the mine ventilation plan is the key
element of an operator's strategy to control respirable dust in the
work environment, thereby protecting miners. In recognition of this,
MSHA's proposal makes a number of changes to the process for
evaluating, approving, and monitoring mine ventilation plans, many of
which are based on the Advisory Committee's recommendations.
Consistent with the Advisory Committee recommendations, MSHA
proposes to add provisions to verify the effectiveness of the
ventilation plan in controlling dust, at a production level high enough
to demonstrate the plan's effectiveness under typical operating
conditions. This would require that MSHA implement procedures for
reviewing compliance and production records. It would also require that
dust control parameters and production associated with samples on a
given shift be recorded in order to demonstrate that parameters
specified continue to be effective in controlling dust.
This proposal would require a ventilation plan to include all
engineering or environmental controls necessary for maintaining dust
concentrations at acceptable levels. A plan must also include any
specific work practices or other means used to supplement these
controls in order to minimize the dust exposure of individual miners.
Unlike plans under the current program, you would have to identify all
measures necessary for achieving continuous compliance with the
applicable dust standard in the plan.
MSHA proposes to require you to include information on the length
of each normal production shift in Sec. 75.371(f) and to specify the
VPL as defined in Sec. 70.2 in every ventilation plan. The VPL is the
tenth highest production level recorded in the most recent 30
production shifts. This value will represent the minimum production
level at which effectiveness of the plan must be demonstrated.
We believe that the production criteria used to evaluate plan
effectiveness may not adequately represent typical conditions under
which miners work. Requiring that plans be verified at or above the VPL
would provide assurance that excessive dust concentrations will be
avoided, even on shifts with higher-than-average production. This is
more protective of miners than the current practice of evaluating plan
adequacy based on MSHA inspector samples taken when production can be
as low as 60 percent of the average production.
MSHA would require you to maintain records of the amount of
material produced by each MMU during each shift. This would enable you
to establish the VPL. Because verification of a plan's effectiveness is
conditioned on the VPL, these records are necessary to ensure that the
VPL continues to represent higher-than-average production. Although a
VPL would be included in the ventilation plan, MSHA would not cite you
for producing at levels exceeding the VPL.
Under the proposed plan verification procedures, MSHA will notify
you of when we intend to initiate verification sampling. To enable MSHA
to evaluate the effectiveness of the plan parameters at or above the
VPL, you must make sure that all the dust control parameters specified
in your ventilation plan are fully implemented. On the date scheduled
for verification sampling, you should arrange to be producing at or
above the VPL specified in the plan, using only the dust control
parameters and other measures listed in the plan.
Under the proposal, MSHA would perform the sampling necessary to
verify your plan. We will collect full-shift samples from the work
environment of multiple occupations on each MMU, including the DO. We
will collect all samples in accordance with procedures described in
Chapter 1 of MSHA's Coal Mine Health Inspection Procedures Handbook (op
cit.). In addition, on every shift on which we
[[Page 42134]]
collect verification samples, we would measure and record all of the
quantitative engineering or environmental parameters. We would also
record any other means used to reduce miners' dust exposure on the
sampled shift. We will provide you with this information, along with
verification sample results, for posting on your mine bulletin board.
In accordance with section 103(f) of the Mine Act, you must provide
miners and their representatives the same walkaround rights during plan
verification sampling as they are provided during any other physical
inspection made pursuant to the provisions of section 103(a) by an
authorized representative of MSHA.\4\
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\4\ MSHA believes that under the guidance of the Interpretive
Bulletin 43 FR 17546 (April 25, 1978) these rights arise when: (1)
an ``inspection'' is made for the purposes set forth in section
103(a), and (2) the inspector is physically present at the mine to
observe or monitor safety and health conditions as part of direct
safety and health enforcement activity.
Verification sampling is necessary to obtain information related
to approval of the mine's ventilation plan and whether coal mine
dust will be adequately controlled to protect miners health.
Consequently, miners and their representative would have the right
to accompany the inspector with no loss of pay for the time during
which the representative exercises this right. However, this right
is limited by Section 103(f) to only one such representative of
miners.
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Unlike the existing program, the proposal would allow you, for the
first time, to use either approved PAPRs or verifiable administrative
controls to supplement your engineering or environmental controls for
compliance purposes at longwall mining operations. This would be
permitted only on an interim basis and only after MSHA determined that
you had exhausted all feasible engineering or environmental controls.
Finally, under this proposal, MSHA has established rigorous
criteria for determining when to approve a plan. We would approve a
plan only when a sufficient number of verification samples demonstrate,
at a high level of confidence, that the plan is effective at production
levels at or above the VPL.
D. Hierarchy of Dust Controls
Consistent with the Mine Act, engineering or environmental controls
have been the principal method used for preventing or minimizing
miners' exposure to these primary and secondary dust sources in the
workplace over the past 30 years. Control of dust throughout the work
environment gives reasonable assurance that all miners in the area will
be adequately protected. Well-designed engineering or environmental
controls provide consistent and reliable protection to all workers
because they are not dependent upon constant human supervision or
intervention, except for the periodic checks, to insure that they are
functioning as intended. MSHA requires mine operators to utilize all
feasible engineering or environmental controls, which are specified in
the mine ventilation plan, to maintain concentrations of respirable
dust in the work environment of MMUs at or below the applicable dust
standard. Engineering or environmental controls include all methods
that control the level of respirable dust by reducing dust generation
(e.g., machine parameters) or by suppressing (e.g., water sprays,
wetting agents, foams, water infusion, etc.), diluting (e.g.,
ventilation), capturing (e.g., dust collectors) or diverting (e.g.,
shearer clearer, passive barriers, etc.) the dust being generated by
the mining process. The importance of using engineering or
environmental controls was not only recognized by the Advisory
Committee, but also by NIOSH in its criteria document: Occupational
Exposure to Respirable Coal Mine Dust (NIOSH, 1995), when it
recommended that such controls must continue to be relied upon as the
primary means of protecting coal miners. The primacy of engineering or
environmental controls is preserved under this proposal. The proposal
requires mine operators to utilize all feasible engineering or
environmental controls to reduce concentrations of respirable dust to a
level at or below the applicable standard.
Administrative controls are another method of avoiding
overexposure. Administrative controls refer to work practices that
reduce miner's daily exposure to respirable dust hazards by altering
the way in which work is performed. They consist of such actions as
rotation of miners to areas having lower dust concentrations,
rescheduling of tasks, and modifying work activities. The Task Group
found that administrative controls were used increasingly, even when it
was feasible to implement additional engineering or environmental
controls. The use of administrative controls was found to be increasing
at mines employing longwall mining systems. The most frequent
administrative control in use consisted of restricting the activities
of miners required to work downwind of the longwall operator, or the
occupation designated as 044 by MSHA. This particular form of
administrative control is in use at some of the 51 longwall MMUs that
were operating on October 28, 1999. MSHA has observed the use of this
particular administrative control, even after changing the location of
the DO from the 044 to the 060 occupation--the miner who works nearest
the return air side of the longwall working face. Unlike engineering or
environmental controls, to be effective, administrative controls rely
on the ability of miners to follow specified procedures. However,
difficulty in ensuring that miners adhere to the administrative
controls, labor/management agreements, and limitations on the number of
qualified miners capable of handling specific tasks may limit the use
and effectiveness of such controls. The Advisory Committee Report
states that the use of administrative controls does not reduce the
operator's responsibility to maintain ambient dust levels in active
workings at or below the standard. However, the Advisory Committee
noted that ``while not a substitute for engineering controls,
administrative controls, which restrict the amount of time that miners
spend in an area with uniform exposure level, can result in lower
personal exposures (MSHA, 1996).''
Under the Mine Act and current regulations, mine operators are
required to make approved respiratory equipment available to all
affected underground miners whenever exposure to concentrations of
respirable dust exceeds the applicable dust standard. However, miners
are not compelled to use them. While required for interim protection,
mine operators cannot use respirators as a substitute for engineering
or environmental control measures. Engineering or environmental
controls have been found to provide more consistent and reliable
protection to all workers. In comparison to respirator programs, the
effectiveness of engineering or environmental controls does not rely
heavily upon constant supervision or miners' consistent and correct use
of the equipment. Furthermore, we can measure dust concentrations to
which miners are exposed when engineering or environmental controls are
in use. It is more difficult to monitor the effectiveness of a
respirator program because the assessment methods are indirect. For
these reasons, MSHA's longstanding policy has been that respirators
should be used in underground coal mines only as an interim method of
protection until feasible engineering or environmental controls are
available.
Approved respirators are not acceptable substitutes for feasible
engineering or environmental controls.
[[Page 42135]]
It is MSHA's position that technology is available to control
respirable dust to at or below the applicable standard at MMUs
employing continuous and conventional methods of mining. However, MSHA
recognizes that, unlike other mining systems, longwall MMUs may have
acute dust problems caused by the face-ventilation airstream carrying
the shearer-generated face dust over the miners working along the face
downwind of the shearer operator (occupation code 044). This makes it
more difficult to control the work environment on a consistent basis.
Improvements in dust control technology have not kept pace with
increases in production technology associated with high-production
longwall MMUs. Average longwall shift production reported during
bimonthly sampling has increased more than five-fold since 1980, from
approximately 890 tons per shift (tps) to more than 4,900 tps in 1998.
In fact, 49 percent of the shifts sampled averaged 4,000 to 8,000 tps,
while approximately 8 percent of the shifts exceeded 8,000 tps. A major
milestone in mining history was achieved in 1997, when a single
longwall mine produced more than 1 million tons of coal in a single
month (Fiscor, 1998).
Unfortunately, as more coal is mined, greater quantities of
respirable dust are generated. The increase in longwall production
levels has resulted in the generation of far more dust which must be
controlled (Webster, et al., 1990; Haney, et al., 1993; O'Green, 1994).
According to published literature, several thousand milligrams of
respirable dust per ton of coal cut can be formed and liberated during
the cutting process (National Research Council, 1980). Of course, the
quantity of respirable dust produced by the cutting process can vary
greatly, depending on the type of coal, its moisture content, the
amount of rock bands in the coal, sharpness of the cutting bits, the
particular mining machine, and many other factors. Although a
considerable amount of respirable dust is formed by the cutting
operation, most of these particles do not become airborne.
Nevertheless, given the amount of dust that is produced per ton of coal
mined, a larger quantity of respirable dust would be generated from
cutting 8,000 tons of coal than from cutting 4,000 tons. An operator is
not required to produce, on a sampled shift, more than 50 percent of
the average production reported during the last bimonthly period.
Therefore, dust concentrations on sampled shifts may be substantially
lower than what is typical and therefore not reflect the dust exposure
on that shift.
While significant efforts have been made to implement available
control technology, no significant new advancements in longwall control
technology have been reported since 1989 (U.S. Bureau of Mines,
undated). From 1989 to 1999, the percentage of operators' longwall DO
samples exceeding 2.0 mg/m\3\ dropped from 34 percent to 20 percent,
reflecting the impact of the implementation of those advances in
longwall control technology. Although this represents a significant
improvement, especially in view of the five-fold increase in average
shift production, the 1999 data clearly show that miners continue to be
overexposed on a significant number of shifts.
Over the past ten years, MSHA and the former U.S. Bureau of Mines,
now part of NIOSH, have made unsuccessful efforts to conduct a joint
research program that would evaluate the effectiveness of available
longwall dust control technology. The objective of such research would
have been to quantify the effects of employing all state-of-the-art
dust-control technology available for a longwall operation.
Unfortunately, such a study has never been undertaken because no
industry partner has agreed to participate. Based on our experience,
MSHA's position remains that feasible engineering and environmental
controls exist for maintaining dust exposures at or below the
applicable standard, even at longwall operations. MSHA has concluded
that the proposed plan verification process will lead to further
improvements in the design and quality of mine ventilation plans. At
some high-producing longwall MMUs, however, the engineering or
environmental controls available may not succeed in sustaining
continuous compliance with the applicable dust standard at certain
locations downwind of the longwall operator (occupation code--044).
Mining industry representatives have repeatedly urged MSHA to
accept the use of powered, air-purifying respirators (PAPRs) (e.g.,
Racal<Register> Airstream helmets),\5\ as an alternative means of
complying with the applicable dust standard when engineering or
environmental controls failed or were not feasible. The Airstream
helmet originated in the early 1970s at the Safety in Mines Research
Establishment in England which developed it primarily for mining use to
provide protection for head, eyes, and lungs in a single convenient
unit. Because these devices provide a continuous stream of filtered air
over the miner's face, it has been suggested that they be viewed as
miniature environmental controls, rather than respirators. In September
1997, Energy West Mining Company (Energy West) petitioned the Secretary
of Labor to amend the mandatory health standards for underground coal
mines at 30 CFR part 70 to allow Airstream helmets or other types of
PAPRs to be used as a supplemental means of complying with the
applicable dust standard. The petition for rulemaking proposed that the
Secretary issue a standard which would supersede the current interim
statutory standard, specified in Section 202(h) of the Mine Act. Energy
West contended that PAPRs are necessary as a supplemental means of
controlling respirable dust because even the most diligent application
of feasible engineering/environmental controls could not always prevent
overexposure. MSHA has consistently acknowledged that PAPRs can be
effective as an interim method of protecting miners when properly
selected, used, and maintained. However, MSHA has never considered the
Racal<Register> Airstream helmet (or the 3M\TM\ Airstream\TM\ Helmet-
Mounted PAPR), or any other respiratory protective device approved and
labeled as such by the National Institute for Occupational Safety and
Health (NIOSH), to be an engineering, environmental, or administrative
control. Hence, it cannot be used as an environmental control to comply
with the respirable dust standard.
---------------------------------------------------------------------------
\5\ References to specific equipment, trade names or
manufacturers does not imply endorsement by MSHA.
---------------------------------------------------------------------------
In order to provide the greatest possible protection for all miners
under typical mining conditions, MSHA is proposing to permit, under
certain circumstances, the limited use of either approved loose-fitting
PAPRs or verifiable administrative controls for compliance purposes.
This would provide you with the flexibility to select the most
appropriate option for supplementing your engineering or environmental
controls. We believe that permitting longwall mine operators to use
loose-fitting PAPRs or verifiable administrative controls for
compliance purposes will not reduce the level of protection afforded
longwall miners by the existing standard.
This aspect of the proposal is limited to longwall mine operations
because technology is available to control respirable dust at or below
the applicable standard at MMUs employing continuous and conventional
methods of mining. Their use at longwall operations would be permitted
[[Page 42136]]
only after MSHA determines that for a specific MMU, excessive dust
concentrations cannot be prevented in the environment of miners
required to work downwind of the longwall shearer operator (occupation
code--044) by implementing all feasible engineering or environmental
controls. We solicit comments concerning the availability of feasible
engineering or environmental controls to lower dust levels.
1. Selection of Respirators: Loose-Fitting PAPRs
Loose-fitting PAPRs completely surround the head and cover the face
with a full visor or shield. The functional and physical
characteristics of loose-fitting PAPRs as described below make them
especially well-suited to underground coal mining conditions, and it is
for these reasons that MSHA determined that loose-fitting PAPRs are the
most suitable type of respirator protection for these conditions.
A loose-fitting PAPR protects the wearer from excessive levels of
respirable dust by providing a continuous flow of filtered air and
imposing minimal breathing resistance upon the wearer. Loose-fitting
PAPRs do not require fit-testing,\6 7\ unlike tight-fitting
respirators. Furthermore, it is not necessary to be clean shaven for
this type of PAPR to be protective.
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\6 7\ Quantitative fit testing and qualitative fit testing are
methods used to determine the facepiece seal and fit of a tight-
fitting respirator.
---------------------------------------------------------------------------
Loose-fitting PAPRs provide safety advantages over other forms of
PAPRs or tight-fitting respirators. In addition to protecting the
lungs, the helmet and visor of a PAPR can simultaneously protect the
eyes and head from high-velocity nuisance dust, spray, and small pieces
of coal from the cutting drums and face and from loose coal falling
from the roof. Loose-fitting PAPRs provide easier communication between
miners, rather than the muffled communication between workers which is
experienced between miners wearing tight-fitting facepieces.
The Racal<Register> Airstream helmet has been in use in underground
coal mines since the late 1970s. Over 50 percent of the longwall mines
operating have miners who wear Airstream helmets for added protection.
This respirator was developed primarily for mining use by the Safety in
Mines Research Establishment (SMRE) in England. It combines face, head,
and respiratory protection in a single convenient unit. The support
hardware which provides the filtered air is packaged in the helmet.
Power for the system is provided by a belt-mounted battery. Dusty air
enters the helmet through a rear entrance port, passes through a pre-
filter assembly that removes the coarse material, and then passes
through the fan and into a final-filter assembly that is located
between the head of the wearer and the outer helmet shield. The
filtered air then sweeps down across the wearer's face, behind the
face-shield visor, and exits at the chin. Soft plastic seals join the
face-shield visor to the sides of the head and jaw limiting entry of
unfiltered mine air (Greenough, 1979). The original Airstream helmet
has undergone numerous design improvements since it was first
introduced in British coal mines in the mid 1970s. The Airstream helmet
is produced by 3M (3M\TM\ Helmet-Mounted Airstream\TM\ series).
2. Protection Factor for Loose-fitting Powered, Air-Purifying
Respirators
The type and degree of protection of any respirator depends on the
ability of a respirator to prevent hazards from entering the worker's
breathing zone. In an underground coal mine, the level of protection
afforded by a loose-fitting PAPR to protect a miner depends on the type
and condition of the filter material of the air-purifying element, the
nature and concentration of the respirable coal mine dust, proper
maintenance of the PAPR and battery pack, and especially, how
consistently the miner properly wears the PAPR, including having the
visor properly lowered. The protection factor, the ratio of the
respirable dust concentration outside the respirator to the
concentration inside, measure how much protection a respirator might
provide to the wearer.
In the NIOSH Respirator Decision Logic (May 1987), based on
simulated laboratory tests and some workplace protection tests (none of
which replicated conditions in underground coal mines) NIOSH assigned
loose-fitting, helmeted PAPRs, properly worn, a protection factor (APF)
of 25. NIOSH made the following cautionary statement:
Despite the fact that some of the PF's [APFs] have a statistical
basis, they are still only estimates of the approximate level of
protection. It must not be assumed that the numerical values of the
APF's presented in this decision logic represent the absolute
minimum level of protection that would be achieved for all workers
in all jobs against all respiratory hazards. The industrial
hygienist or other professional responsible for providing
respiratory protection or evaluating respiratory protection programs
is therefore encouraged to evaluate as accurately as possible the
actual protection being provided by the respirator (NIOSH, May
1987).
Furthermore, in its Guide to Industrial Respiratory Protection
(September 1987), published after the NIOSH Respirator Decision Logic,
NIOSH offered an additional caveat with regard to the effectiveness of
PAPRs:
Until recently, powered air-purifying respirators were
considered positive pressure devices. Field studies by NIOSH as well
as others, have indicated that these devices are not positive
pressure, and that their assigned protection factors are
inappropriately high (NIOSH, September 1987).
There is virtually no positive pressure in the PAPR. Respirable
dust may invade the miners' breathing zone through openings along the
side and bottom of the visor, even when it is maintained in the full
lowered position. The extent to which respirable dust invades a miner's
breathing zone, depends, in part, on the MMU's ventilation air velocity
and on the miner's work rate and his angle of orientation to the
airflow.
Questions have arisen concerning the applicability of NIOSH's APF
of 25 for loose-fitting PAPRs to some work environments. It has been
contended that NIOSH overestimates the minimum level of protection
provided in the workplace even when used within the context of a good
respirator program (Myers, et al., 1984). The environmental conditions
assumed in NIOSH's estimation of the APF for loose-fitting PAPRs are
not consistent with those in underground longwall mining operations.
For example, various unique conditions of coal mining (obstructed views
and difficulty communicating) may compel miners to lift their visors.
Once the visor is raised, the respirator is no longer being worn in
accordance with conditions required for an APF of 25. Also, the high
velocities of air customarily found on longwall mining faces, are not
comparable to the air velocities experienced in most industry sectors
nor in those represented in the studies used to determine the APF of
25. The actual fit or seal of the respirator helmet to the wearer,
repeated work-task motions in confined work spaces, raising the visor,
and high air velocities along the longwall face all may significantly
reduce the actual degree of protection provided in the workplace.
Unlike an APF, an effective protection factor (EPF) reflects the
protection provided by a respirator over an actual work shift given
specific occupational environmental conditions such as ventilation
velocity, when the wearer performs typical work activities and uses the
respirator in a typical manner.
Laboratory and in-mine studies (EPF studies) show that mine
ventilation air flow or velocity, the primary means
[[Page 42137]]
longwall operators use to control respirable dust levels, may be the
single biggest factor affecting the level of protection provided by the
PAPR on a longwall mining face. Cecala, et al., (1981) found protection
of loose fitting PAPRs (Racal<Register> Airstream helmets) to be
inversely related to ambient air velocity in both laboratory and in-
mine settings (Ibid). In other words, increased air velocity leads to
decreased effectiveness of the PAPR.
The level of protection from a loose-fitting PAPR is also affected
by the orientation of the helmet to the airflow. Cecala's wind tunnel
tests clearly showed that, at the higher flow rates, helmet efficiency
was greatest when facing directly against the airflow and was reduced
when the helmet was oriented in other directions. This is extremely
important since miners are more likely to orient their heads at an
angle to the airflow, or to face downwind, than to face directly into
the airflow.
Cecala's in-mine testing of the loose-fitting, helmeted PAPRs
produced an EPF confirming the inverse relationship between wind speed
and the level of protection provided by PAPRs shown during wind tunnel
testing. Air velocity in underground mines is measured in units of feet
per minute (fpm). Under normal face-velocity conditions (less than 400
fpm), the Airstream helmet averaged a respirable dust reduction of 84
percent, which is equivalent to an EPF of 6.4. However, under high
face-velocity conditions (1,200 fpm), the helmet's dust reduction
efficiency decreased significantly, averaging only 49 percent, which is
equivalent to an EPF of 2.
Other researchers have reported that helmeted PAPR systems are
vulnerable to inward leakage into the wearer's breathing zone (Howie,
et al., 1987; Sherwood, 1991). For example, Howie, et al., found that
increasing airflow velocities from approximately 400 to 800 fpm doubled
the inward leakage of the helmet when the airflow impinged on the
wearer's head only, and increased the leakage further when the airflow
impinged on the wearer's body and head (Howie, 1987). Subsequent
testing of a redesigned unit at a wind velocity of approximately 700
fpm showed decreased inward leakage, yielding a protection factor of
6.3. This met the target protection factor of 5, which was subsequently
proposed by the European Community to be the standard for powered
helmet respirators.
More recent studies conducted by Bhaskar, et al. (1994) at four
medium-velocity western longwalls indicated loose-fitting PAPRs had an
average dust reduction efficiency of 83.8 percent (Ibid.). Although a
different sampling procedure was used, this result is consistent with
the average value of 84 percent obtained by Cecala, et al., under
normal mine face-velocity conditions. During the test period, the
headgate velocity ranged from 345 to 500 fpm, with approximately 88
percent of the recorded velocities falling below 500 fpm. The tailgate
velocities ranged from 280 to 550 fpm and only one exceeded 500 fpm. No
tests were conducted under high mine face-velocity conditions.
The headgate and tailgate velocities observed by MSHA inspectors at
55 longwall MMUs were reviewed in 1999. The headgate and tailgate
velocities ranged from 365 to 1,645 fpm and from 200 to 1,400 fpm,
respectively. More importantly, headgate velocities at 60 percent of
the MMUs exceeded 500 FPM and some 18 percent exceeded 800 fpm.
Approximately 55 percent of tailgate velocities exceeded 500 fpm and 11
percent exceeded 800 fpm.
PAPRs have been demonstrated to be effective on longwall MMUs when
air velocities do not exceed 500 fpm, but, as described above, there is
evidence that their effectiveness is reduced when air velocities are
increased. Therefore, given the range of observed longwall face air
velocities to which miners are exposed and the proposed requirement
that the verified ventilation plan demonstrate that the longwall
shearer operator (occupation code--044) be at or below the applicable
standard, MSHA is proposing to grant a protection factor of two for
loose-fitting PAPRs used under this proposal. Multiplying either the
respirable dust standard or the verification limit (whichever is
applicable) by the protection factor yields the maximum concentration
of respirable dust against which a particular type of respirator can be
used. In other words, if MSHA permits a longwall operator to use PAPRs,
then the maximum concentration of respirable coal mine dust and quartz
dust against which these particular respirators can be used are 4.0 mg/
m\3\ and 200 <greek-m>g/m\3\, respectively. A complete respiratory
protection program is required to assure that a respirator's protective
value is not compromised by improper fitting or usage.
MSHA's determination is based on the best scientific and technical
information available as well as sound engineering judgment. However we
encourage you to submit comments on the protection factor. We are
particularly interested in obtaining more recent data that may be
available concerning protection factors as well as the conditions for
the use of PAPRs. If you believe MSHA should establish a different
protection factor, please submit these data supporting your position.
E. Guidelines for Determining What Is a Feasible Dust Control
The proposal would require a mine operator to implement all
feasible engineering or environmental controls that are technologically
and economically feasible. The Federal Mine Safety and Health Review
Commission (Commission) has addressed the issue of what MSHA must
consider, when determining what is a feasible control for enforcement
purposes. In cases involving the noise standard for metal and nonmetal
mines, the Commission has held that a control is feasible when it: (1)
reduces exposure, (2) is economically achievable, and (3) is
technologically achievable. See Secretary of Labor v. Callanan
Industries, Inc., 5 FMSHRC 19 00 (1983), and Secretary of Labor v. A.
H. Smith, 6 FMSHRC 199 (1984).
In determining technological feasibility of an engineering control,
the Commission has ruled that a control is deemed achievable if through
reasonable application of existing products, devices, or work methods
with human skills and abilities, a workable engineering control can be
applied to the exposure source. The control does not have to be ``off-
the-shelf'' or already available but, it must have a realistic basis in
present technical capabilities. Further, the Commission has held that
MSHA must assess whether the cost of the control is disproportionate to
the ``expected benefits,'' and whether the cost is so great that it is
irrational to require its use to achieve those results. The Commission
has expressly stated that cost-benefit analysis is unnecessary in order
to determine whether an engineering control is feasible. According to
the Commission, an engineering control may be feasible even though it
fails to reduce the exposure to permissible levels in the standard, as
long as there is a significant reduction in exposure.
Consistent with the Commission case law, MSHA would consider three
factors in determining whether engineering or environmental controls
are feasible at a particular mine: (1) the nature and extent of the
overexposure; (2) the demonstrated effectiveness of available
technology; and (3) whether the committed resources are
disproportionate to the expected results. As explained in the
discussion of proposed Sec. 70.211 in Section IV of the
[[Page 42138]]
proposal, the formal determination of whether all feasible engineering
or environmental controls have, in fact, been implemented at a specific
mine to prevent excessive dust concentrations would be made by the
Administrator for Coal Mine Safety and Health based on the best
available information, experience, and engineering judgment.
F. Application of Continuous Monitoring Technology to Prevent
Overexposures on Individual Shifts
Because approved technology that continuously monitors respirable
dust and displays dust concentrations in real-time is not available,
effective ventilation plans remain the only practical means to provide
reasonable assurance, on a continuous basis, that miners are not
overexposed on individual shifts. However, MSHA recognizes that person-
wearable continuous respirable dust monitors under development may lead
to significant improvements in monitoring the work environment in order
to improve miner health protection. In an effort to reduce occupational
respiratory disease among underground coal miners, MSHA encourages mine
operators to adopt new and better dust monitoring technology as part of
the approved ventilation plan.
Unlike the current monitoring system, which relies on periodic
sampling and requires that corrective action be taken after the
necessary delay in obtaining dust level information, continuous
monitoring would allow mine operators and miners to be aware of the
actual dust conditions at all times, thereby enabling immediate action
to avert possible overexposure. The ability to monitor dust exposure
continuously during the shift, predict end-of-shift cumulative
exposures, and to display the actual end-of-shift exposure would be far
more effective in preventing simple CWP and PMF than the current
system.
The health benefits of continuous monitoring were clearly
recognized by both the Task Group and the Advisory Committee. Both
recommended development, field testing, and immediate deployment of
such monitors for a variety of purposes. The Task Group concluded that
continuous monitoring of the mine environment and dust control
parameters offered the best long-term solution for improving the
existing federal program designed to prevent simple CWP and PMF among
coal miners. Similarly, the Advisory Committee stated in its report
that:
Worker exposure to excessive levels of dust can be prevented by
implementing a hazard surveillance program that provides mine
personnel with current information on actual dust levels in the work
environment at all times, and on the status of key dust control
parameters. The availability of this information on a real-time
basis would enable mine personnel to focus attention immediately on
the need to adjust control parameters to avert possible
overexposure. The recent development of continuous dust and
continuous dust control parameter monitors, which have both direct
reading and data recording/processing capabilities, offers the
potential to improve monitoring of the work environment
significantly and contribute to the effective control of exposure.
(MSHA, 1996).
MSHA has sought a means to measure the concentration of respirable
coal mine dust in coal mines on a continuous basis for nearly two
decades. Beginning in the 1970's, at the request of MSHA, the former
U.S. Bureau of Mines funded several developments of fast-response,
direct-readout respirable dust monitors for measuring the concentration
of respirable dust.
One type of fast-response respirable dust monitor determined the
mass of respirable dust particles collected on a grease-coated disk by
the attenuation of beta radiation caused by the dust spot on the
impaction disk. The unit was capable of operating for long periods,
taking up to 450 1-minute samples, and printing the individual and
time-integrated concentrations on a tape.
Other devices have used light-scattering technology to measure and
provide an immediate direct readout of dust concentrations. Since light
scattering is often dependent on particle characteristics such as size,
surface properties, and refractive index, this type of dust monitor
does not measure a mass concentration directly and can provide only a
relative measurement. However, it can be calibrated in the laboratory
to give an approximate mass concentration.
The light-scattering technology was later incorporated in a
machine-mounted, continuous respirable dust monitor for use in
underground mines. In the early 1980's, however, it was determined that
this technology was not effective for monitoring compliance with the
applicable dust standard. Nevertheless, instruments which used the
light scattering principle were found to be useful tools to locate dust
sources and to determine its magnitude. Such instruments continue to be
especially useful for evaluating dust-control techniques such as dust
collectors and water sprays that can be turned on and off quickly and
repeatedly.
The 1992 Task Group report recommended the accelerated development
of a fixed-site underground dust monitor, capable of providing
continuous information on dust levels and personal sampling devices
capable of providing both short-term and full-shift exposure
measurements. In response to this recommendation, the former Bureau of
Mines, with MSHA's assistance, again evaluated existing technology that
could be used in the development of a fixed-site underground mine dust
monitor. This was made possible because of advances in sensing and
electronic signal processing technology that had occurred since
development of the first generation machine-mounted dust monitor in the
late 1970's. Eventually a fixed site/machine-mounted continuous
respirable dust monitor based on the proprietary mass-measurement
technology known as the tapered element oscillating microbalance
(TEOM<Register>) was developed and field tested.
The TEOM technique is capable of continuously weighing a filter
upon which dust is collected. It provides a real-time record and a
permanent record of the total mass collected on the filter. The device
can display the time-weighted average (TWA) concentration of respirable
coal mine dust (total mass of dust collected divided by the length of
time the unit was operated), the instantaneous (real-time)
concentration, and the projected full-shift concentration. This would
allow a mine operator to adjust control measures or optimize mining
procedures to prevent miner overexposure. The full-shift concentration
of respirable coal mine dust would be available at the end of the
shift. The developer of the fixed-site monitor is also working on a
person-wearable, end of shift/continuous respirable dust monitor using
the same TEOM technology.
In addition to the TEOM technology, NIOSH is developing another
person-wearable device that has the potential for continuously
monitoring the mine environment. This device measures the mass of
respirable dust indirectly based on the amount of pressure drop
detected across the collection filter.
MSHA is seeking ways to encourage voluntary deployment of this
technology, once it has been verified as reliable. MSHA has considered
allowing mine operators to adopt a continuous personal monitoring
strategy as part of the approved ventilation plan, in lieu of plan
verification. Under this approach, the operator would have the
flexibility of choosing from several technologies available for
continuous personal monitoring. If an operator adopts continuous
personal monitoring, the following additional information, at a
[[Page 42139]]
minimum, would be required for the mine ventilation plan:
1. The specific continuous personal monitoring device the operator
intends to use which has been approved by the Secretary;
2. The DO and other occupations or individuals, including part 90
miners, that will be sampled on every production shift and the length
of the production shift to be sampled;
3. The procedures for preventing exposure above the applicable dust
standard;
4. The manufacturer's calibration and maintenance requirements, and
a description of how records of calibration and maintenance will be
made available to MSHA, miners and the miner's representatives; and
5. A description of how end-of shift measurements will be recorded,
who will certify that such records are accurate and properly taken, how
long such records will be maintained, where such records will be made
available for inspection by MSHA, miners and the miner's
representatives, and how miners will be notified on each production
shift of the end-of-shift measurements.
At the present time, we do not believe that technology to enable
continuous monitoring of respirable dust has advanced to the point
where it could be relied upon as an alternative to plan verification.
In the future, when this technology is available, MSHA will consider
the implementation of such an alternative to the proposed plan
verification program. We request comments on this approach as a
possible alternative to plan verification. MSHA is specifically
interested in any proposals for the use of continuous personal
monitoring, as well as any information which may be available
concerning developing technology. Should an operator be interested in
implementing a continuous personal monitoring program at a specific
mine, MSHA will review the plan and consider development of a pilot
program to develop information which may be useful for future
rulemaking. MSHA is interested in comments concerning the specific
provisions which should be included in the ventilation plan to assure
that, if an operator does develop a continuous monitoring program,
miners will not be overexposed on any individual shift.
IV. Discussion of Proposed Rule
A. Summary
As recommended by the Advisory Committee in 1996, MSHA is proposing
to assume responsibility for all compliance sampling for respirable
dust in underground coal mines as required under CFR parts 70 and 90.
This proposal includes revocation of bimonthly compliance sampling
requirements, abatement sampling requirements, the process for
establishing a reduced standard when quartz is present, and operator
sampling requirements for miners who have evidence of the development
of pneumoconiosis under part 90. In order to provide a greater level of
protection than that provided under these sampling requirements, MSHA
is proposing to require each underground coal mine operator to have a
verified mine ventilation plan. Under this proposal, MSHA would verify
the effectiveness of the mine ventilation plan for each mechanized
mining unit (MMU) in controlling respirable dust under typical mining
conditions.
Mine ventilation plans have long been recognized as a means of
addressing mine-specific health and safety issues. Existing Sec. 75.370
requires that each mine operator design a ventilation plan to control
methane and respirable dust in the mine. It further requires that the
plan be suitable to the conditions and mining system at the mine.
However, there is no current provision requiring the effectiveness of
mine ventilation plans to be verified under typical mining conditions.
Since 1970, beginning with enforcement of the Federal Coal Mine
Health and Safety Act of 1969, the level of respirable dust in
underground coal mines has been significantly reduced. Although much
progress has been made, MSHA sampling data indicate that some work
environments continue to have excessive concentrations of respirable
dust. It is MSHA's position that excessive dust levels can be
substantially reduced, if not eliminated, by implementing the Advisory
Committee's recommendations to enhance plan quality and strengthen the
plan approval process. Toward this end, this proposal would revise 30
CFR by revising part 70, subparts A, B, and C amending two existing
sections of part 75.
This proposal would require evidence that the mine ventilation plan
is effective in controlling respirable dust as required by Sec. 75.370.
Within the first 30 days of operating a new MMU, or when required to do
so by the District Manager, mine operators would have to specify the
operating parameters of an effective plan and then MSHA would verify
the plan's effectiveness based on a sufficient number of full-shift
samples taken at designated locations.
Under this proposal, we would collect full-shift respirable dust
samples, called ``verification samples,'' to demonstrate the adequacy
of the dust control parameters specified in the mine ventilation plan
in maintaining the concentration of respirable coal mine and quartz
dust at or below 2.0 mg/m\3\ and 100 <greek-m>g/m\3\, respectively.
For purposes of plan verification, ``full-shift'' would refer to
the entire work shift during which material is produced by an MMU.
Currently, many mining operations have work shifts of more than 8
hours. Miners working extended shifts should be protected from the
hazards of respirable dust and quartz by the ventilation plan.
Accordingly, the proposed verification samples would not be limited to
8 hours or less, as under the current bimonthly operator sampling
regulations.
A sample would be valid for verification purposes only if the shift
on which it was taken met certain requirements. This is necessary in
order to verify that dust controls specified in the plan are sufficient
to prevent excessive dust concentrations, even when a higher-than-
average amount of material is produced. The proposed operator's
requirements for a shift used for verification sampling are:
(1) The dust controls and work practices utilized must be those
listed in the mine ventilation plan;
(2) MSHA's measurements of the engineering or environmental control
parameters must not exceed 115% of the quantities specified in the
plan; and
(3) The amount of material produced must be at least the
``verification production level'' or VPL.
The VPL is defined as the tenth highest production level recorded
in the most recent 30 production shifts.
The proposed rule would require mine operators to: (1) Set and
maintain the dust control parameters during MSHA verification sampling
at levels specified in the plan; (2) maintain and make available to
MSHA records of the amount of material produced by each mechanized
mining unit during each production shift; and (3) provide additional
information in mine ventilation plans.
The number of samples necessary to verify that the dust control
parameters proposed for an MMU are effective would depend on the
individual sample. Since all such measurements are subject to potential
sampling and analytical errors, some of them may fall slightly below
the verification limit even when the true concentration of respirable
coal mine dust or quartz does not. Therefore, to ensure that the
verification limits have actually been met, it is necessary to provide
for a margin of error in each measurement.
[[Page 42140]]
The ``critical values'' established by MSHA provide this margin of
error. If the VPL is achieved and dust concentrations are sufficiently
low, the District Manager could approve a plan based on as few as one
shift of sampling. However, if dust concentration measurements are
higher, or if the actual production was less than the VPL MSHA would
sample additional shifts.
Consistent with the Mine Act and its implementing regulations,
MSHA's longstanding policy has been to preserve the primacy of
engineering controls, to the extent that they are technologically and
economically feasible. Consequently, MSHA has not accepted the use of
approved respiratory protection or administrative controls as a means
of achieving compliance with the respirable dust standard. In order to
provide all miners with the highest possible level of health
protection, as intended by the Mine Act, MSHA is now proposing to
permit the use of approved PAPRs or verifiable administrative controls
to supplement engineering or environmental controls under certain
circumstances for compliance purposes. Their use would be limited to
longwall mining operations and permitted only after MSHA has
determined, upon request of the operator, that all feasible engineering
or environmental controls cannot maintain the mine atmosphere within
applicable standards. In such cases, specific requirements governing
the use of PAPRs or verifiable administrative controls would be
specified in the mine ventilation plan.
Finally, the proposal would require you to maintain, and make
available to MSHA inspectors, records of the amount of material
produced by each MMU during each production shift over a running six-
month period. This, along with routine bimonthly and other sampling
data, would enable us to review the suitability of the plan parameters
on an ongoing basis.
Although a VPL would be included in the ventilation plan, we would
not cite you for producing at levels exceeding the VPL. We would expect
production on an MMU to exceed the VPL on about 33 percent of all
production shifts. If the District Manager determines that your
production exceeds the VPL on more than about 33 percent of the
production shifts over a six-month period, then this may trigger the
plan verification process using a higher VPL.
These and other provisions of the proposed rule are explained in
more detail in the following section-by-section discussion.
B. Section-by-Section Discussion
This section of the preamble explains, section-by-section, the
provisions of the proposed rule. The text of the proposed rule is
included at the end of the document.
Section 70.2 Definitions
The existing definitions of certified person, concentration, and
designated area (DA) are being modified to more clearly convey the
intended meaning under the proposal. These modifications reflect
necessary changes as a result of the removal of existing paragraphs and
the transfer of other paragraphs, as well as the addition of new
references. The proposal also includes definitions of new terms to
clarify the mine ventilation plan verification process as it applies to
mechanized mining units (MMUs). Some of the definitions are for
technical terms developed specifically for this proposal, such as
``verification limit'' and ``verification production level.'' Finally,
the definitions of ``certified person,'' ``normal production shift,''
and ``valid respirable dust sample'' would be removed.
We explain these new and revised definitions of terms below. You
should also closely examine each proposed section where the term is
used to review the context in which it is used.
The following existing definitions are being modified:
Concentration
The existing definition would be modified so that ``concentration''
refers to an 8-hour Mining Research Establishment (MRE) equivalent
measure of the amount of sampled material contained per unit volume of
air. The proposed revision would include the constant factor of 1.38
which the Secretary currently uses to convert concentration of
respirable dust measured with approved sampling devices to an
equivalent concentration as measured with an MRE instrument.
MSHA developed the existing coal mine dust standards from 8-hour
shift exposure measurements. Therefore, if you take a sample over a
period other than eight hours, you must adjust the concentration
measurement to be equivalent to an eight-hour exposure. This will
protect miners working shifts longer than eight hours, and would be
accomplished by multiplying the sampler flow rate by 480 minutes,
regardless of the length of time during which the sample was actually
collected. (In these examples, to determine equivalent concentrations
of respirable coal mine dust: MRE equivalent concentration (mg/m\3\)=
[GRAPHIC] [TIFF OMITTED] TP07JY00.001
where: rate of sampling = 0.002 m\3\/min).
For example, suppose a DO sample is collected over a 9-hour shift
that includes one hour of travel time. Suppose that the amount of dust
accumulated during travel is negligible, and the amount of dust
accumulated during production is 1.5 mg. If the concentration were not
adjusted to an 8-hour equivalent, it would be diluted by the time spent
traveling and calculated as 1.92 mg/m\3\. Under the proposed
definition, the calculated concentration would be 2.16 mg/m\3\.
The proposed definition does not change the daily limit on
accumulated exposure intended by the existing exposure limit for coal
mine dust. Since the current limit was based on an assumption that
exposure occurs over an 8-hour shift, it corresponds to a daily
cumulative exposure limit of 8 x 2.0 = 16 mg-hr/m\3\. The proposed
definition of concentration would maintain this same MRE-equivalent 16
mg-hr/m\3\ daily limit, regardless of the length of any shift worked.
To continue the example, the exposure accumulated during a day is
the same, whether from 8 hours at an average of 2.16 mg/m\3\ or from 9
hours at an average of 1.92 mg/m\3\. In either case, the MRE-equivalent
exposure accumulated for the day is 17.3 mg-hr/m\3\, which exceeds the
intended daily limit of 16 mg-hr/m\3\. Under the proposed definition,
this would be reflected by the fact that the calculated concentration
exceeds 2.0 mg/m\3\. MSHA solicits comments on this method of adjusting
concentrations to an 8-hour equivalent.
[[Page 42141]]
Designated Area (DA)
The existing definition would be modified to permit the Secretary
to identify designated areas and to remain consistent with existing
procedures which have been in effect since 1980. Once identified, the
location of these DAs and the respirable dust measures to be used at
the dust generating sources for these locations must be contained in
the operator's mine ventilation plan as provided for under
Sec. 75.371(t). However, the operator would not be required to sample
these DA's under the proposal. MSHA is also proposing to transfer the
requirement for identifying each DA specified in existing
Sec. 70.208(e), which will be removed, to revised Sec. 70.2(e).
Mechanized Mining Unit (MMU)
The existing definition would be modified by removing
Sec. 70.207(e) (Bimonthly sampling; mechanized mining units) which will
be deleted, and revising Sec. 70.207; and by transferring the
requirements for identifying each MMU specified in existing
Secs. 70.207(f)(1) and (f)(2), to revised Sec. 70.2(o).
Quartz
The existing definition of quartz would be modified by specifying
the analytical method that MSHA has been using since 1983 to determine
the quartz content of respirable dust samples. The reason for this
modification is to standardize the procedure, thereby enabling other
laboratories to reproduce quartz determinations made by MSHA.
The following new definitions are being proposed:
Critical Value
``Critical value'' would mean the maximum acceptable full shift
dust concentration measurement demonstrating that the applicable
verification limit has been met at a high level of confidence. Appendix
A explains how each critical value was derived. The specific critical
values and their use are detailed in Secs. 70.209 and 70.213.
Dust Control Parameters
``Dust control parameters'' would mean the respirable dust control
requirements of a mine ventilation plan, including engineering or
environmental controls, maintenance procedures, and any other
requirements described in a ventilation plan. These requirements are
intended for the protection of miners from excessive levels of
respirable dust and must be in place on every production shift. To
assure compliance with the ventilation plan, you must check the dust
control parameters on each MMU before beginning production, as required
under Sec. 75.362(a)(2). This term has not been formally defined until
now.
Engineering or Environmental Controls
``Engineering or environmental controls'' would mean all methods
that control the level of respirable dust in the work environment by
either reducing dust generation or by suppressing, diluting, capturing
or diverting the dust being generated during the mining process.
Throughout the proposal, the terms ``engineering'' and
``environmental'' controls are used interchangeably. The
Racal<Register> Airstream helmet (or the 3M\TM\ Airstream\TM\ Helmet-
Mounted PAPR), or any other respiratory protective device approved and
labeled as such by the National Institute for Occupational Safety and
Health (NIOSH), is not defined as an engineering or environmental
control.
Full Shift
``Full shift'' is defined differently for purposes of plan
verification and abatement sampling, and for bimonthly compliance
determinations. For purposes of abatement and plan verification, ``full
shift'' would mean an entire work shift, including travel time to and
from the MMU. Because of the way MSHA intends to define
``concentration,'' this would be equally protective regardless of the
production and travel times. For example, suppose miners at one MMU
travel for one hour and mine for eight hours. Miners at another travel
for two hours and also mine for eight hours. Suppose, further, that the
dust concentration during travel is negligible and that the dust
concentrations are identical during production at the two MMUs. Then
the amount of dust accumulated on a filter will be the same, say 1.0
mg, in both cases. Applying the proposed definition, the dust
concentration calculated for both MMUs would be 1.44 mg/m\3\.
For purposes of bimonthly compliance determination, MSHA would
continue its current practice of limiting sampling to a 480-minute
maximum. MSHA solicits comments on whether ``full shift'' for
compliance sampling purposes should be defined in the same way as for
abatement and plan verification purposes. MSHA also solicits comments
on whether ``full shift'' should be defined, as proposed, in the same
way for abatement and plan verification purposes.
Material Produced
``Material produced'' would mean the total amount of coal and/or
other substance extracted by an MMU during any production shift. In
order to properly assess the effectiveness of the mine ventilation plan
requirements for respirable dust control and for subsequent monitoring
purposes, MSHA proposes to require that the operator record and make
available records of the amount of material produced by each MMU each
shift under a new paragraph (h) of Sec. 75.370.
MRE
``MRE'' would mean Mining Research Establishment of the National
Coal Board, London, England.
Powered Air-Purifying Respirators (PAPRs)
``Powered, air-purifying respirators (PAPR)'' would mean a NIOSH
approved loose-fitting respirator that uses a blower to force the
ambient air through air-purifying elements to deliver filtered air to
the miner's breathing area. Under the proposal, an operator who employs
longwall mining has the option of using either powered, air-purifying
respirators (PAPRs) or verifiable administrative controls as a
supplemental means of control once MSHA has determined that
concentrations of respirable dust have been reduced as low as is
feasible with engineering and environmental controls. This may include
RACAL<Register> Airstream helmets or similar devices that are available
now or in the future. The reason for excluding other types of approved
respirators is discussed in section II.B.1.
Verifiable Administrative Control
``Verifiable administrative control'' would mean a work practice
intended to reduce the miner's full shift exposure to respirable dust
hazards by altering the way in which work is performed. Examples
include rotation of miners to areas having lower concentrations of
respirable dust, rescheduling of tasks, and modifying work activities
to reduce exposure. A ``verifiable administrative control'' must be (1)
capable of review to confirm proper implementation; (2) clearly
understood by miners; and (3) applied consistently over time.
Verification Limits
``Verification limits'' would mean the maximum dust concentration
for which the ventilation plan has been verified as effective in
maintaining during the full shift. There are two separate verification
limits: An MRE-equivalent concentration of 2.0 mg/m\3\ for respirable
coal mine dust and an MRE-equivalent concentration of 100 <greek-m>g/
m\3\ for respirable quartz dust. Both of these
[[Page 42142]]
limits apply to dust concentrations measured over a full shift.
MSHA does not enforce a separate standard for quartz dust. It
regulates exposures to quartz and coal mine dust by reducing the
applicable standard for coal mine dust, by means of a formula, when
quartz content of the respirable dust is above 5 percent. This formula
(10 divided by the concentration of quartz, expressed as a percentage)
establishes an applicable coal mine dust standard that, in effect,
limits quartz concentrations in the mine environment to no more than
100 <greek-m>g/m\3\. For example, when the quartz content is 5 percent,
the applicable standard is 2.0 mg/m\3\; when the quartz content is 10
percent, the applicable standard is 1.0 mg/m\3\. Five percent of 2.0
mg/m\3\ and 10 percent of 1.0 mg/m\3\ are each 0.100 mg/m\3\ or 100
<greek-m>g/m\3\.
The Advisory Committee recognized that a significant quartz
exposure hazard continues to exist in coal mines, especially for
operations such as roof bolting. Based on MSHA data, 66 percent of
underground coal mines are operating on a reduced dust standard due to
the respirable dust in the mine environment containing a high
percentage of quartz. MSHA data also indicates that 73 percent of the
over 600 roof bolters and over 29 percent of the MMUs sampled bimonthly
by mine operators are operating under reduced dust standards. The
number of reduced standards in effect indicates that a significant
potential health risk due to quartz exposure continues to exist. Under
the current program, miners can be exposed to excessive quartz levels
while the dust standard-setting process takes place. For example,
consider a recent situation where an MSHA dust sample of a roof bolter
was 0.9 mg/m\3\; a level that was in compliance with the applicable
standard, 1.3 mg/m\3\. However, when the sample was analyzed for quartz
the results indicated that the actual concentration of quartz dust in
the mine environment exceeded 270 <greek-m>g/m\3\; or more than two and
a half times above the permissible level of 100 <greek-m>g/m\3\. The
only action that could be taken in this particular situation was to
initiate the dust standard-setting process, which, on average, can take
at least one month or longer. The existing standard-setting process
continues from the time the operator is cited for violating the reduced
standard through the time MSHA enforces final corrective action.
Under this proposal, MSHA would require operators to anticipate the
potential for quartz exposure and to incorporate controls prior to
approval of the mine ventilation plan. In order to verify that the
operator has incorporated such controls, MSHA would determine the mass
of quartz contained in each verification sample and express the
concentration of quartz in the mine air as an airborne concentration
and not as percent quartz in the dust during the verification process.
This process would require operators to address both the potential
for respirable coal mine dust and quartz dust exposure. As recommended
by the Advisory Committee, the proposed plan verification process would
establish a monitoring and compliance framework to aid MSHA and the
coal mine operator in targeting mining situations where quartz exposure
constitutes a significant hazard and enhanced dust control procedures
are required.
Verification Production Level (VPL)
The ``VPL'' would mean the tenth highest production level recorded
in the most recent 30 production shifts. It is an estimate of the 67th
production percentile within an MMU. (Sec. 70.208 explains how to
establish the VPL if you do not have records for 30 production shifts.)
We believe that the production criteria used to evaluate plan
effectiveness may not adequately represent typical conditions under
which miners work. Requiring that plans be verified at or above this
VPL would provide assurance that excessive dust concentrations would be
avoided on a majority of production shifts. MSHA believes that using
this VPL is more protective of miners' health than the current practice
of evaluating plan adequacy based on MSHA inspector samples taken when
production can be as low as 60 percent of the average production. We
note however, that a VPL defined as a higher production percentile than
is being proposed would likely assure that miners would be more
protected on a majority of production shifts. The Agency welcomes
comments on both the use of a VPL and the appropriate production
percentile to use to define it.
Since approximately 50 percent of all production shifts are
expected to exceed average production, it follows that the vast
majority of all production shifts exceed 60 percent of average
production. Therefore, by using 60 percent of average production as the
lower range of the production criteria for plan evaluation purposes, as
required under current inspection procedures, we have no assurance that
the plan would be effective under the vast majority of production
conditions.
If you do not have records for 30 production shifts, you can use
the minimum production actually achieved on a shift used to verify the
plan's effectiveness as your VPL.
Verification Sample
``Verification sample'' would mean a sample collected for purposes
of plan verification. In order to be valid the sample must be collected
on a full shift during which the amount of material produced is at or
above the VPL. Only those engineering or environmental controls and
other measures listed in the mine ventilation plan may be employed, at
levels not exceeding 115% of the quantities specified in the plan
during the shift in which the sample is collected. For example, if the
plan specifies an air quantity of 4,000 cfm, the quantity measured
during verification must not exceed 4,600 cfm (4,000 cfm x 1.15 =
4,600).
Section 70.100 What are the respirable dust standards when quartz is
not present?
MSHA is proposing no substantive changes to existing Sec. 70.100(a)
and (b), except for removing the reference to Sec. 70.206 (Approved
sampling devices; equivalent concentrations) from existing paragraphs
(a) and (b) and replacing it with revised Sec. 70.2(c). The
requirements of revised Sec. 70.2(c) are similar to the previous
standard in Sec. 70.206. The proposal retains the respirable dust
standard of 2.0 mg/m\3\ in existing paragraph (a) and the intake air
standard for respirable dust of 1.0 mg/m\3\ in existing paragraph (b).
Section 70.101 What is the respirable dust standard when quartz is
present?
MSHA is proposing to retain the existing formula (10 divided by the
concentration of quartz, expressed as a percentage) for reducing the
respirable dust standard below 2.0 mg/m\3\ when the quartz content of
the respirable dust in the mine atmosphere is above 5 percent. However,
the Agency is proposing to change how it arrives at an average quartz
percentage that is used to establish an applicable dust standard.
MSHA recently published a proposed ``Program Policy Letter (PPL) on
Samples Used to Determine the Respirable Dust Level When Quartz is
Present'' for public comment [64 FR 65671, November 23, 1999] whereby
the standard would be determined based solely on the results of
multiple MSHA samples. Under this proposal, as in the PPL, MSHA would
no longer be using a combination of MSHA and mine operator sampling for
determining the average quartz percentage, which has been the practice
since 1985. Instead, as discussed in section III.B, this proposal
[[Page 42143]]
would establish MSHA sampling as the exclusive basis for determining
the reduced standard and require three valid MSHA samples to set a
reduced standard. Since we are sampling underground mines bimonthly, we
will have no difficulty in collecting the required number of samples to
arrive at the average quartz percentage. We believe our samples will be
more representative of the level of quartz to which miners are exposed
than as determined currently. This increased level of sampling should
also allay any operator concerns regarding the collection of
``misleadingly high'' samples during atypical periods. We would also
begin reporting quartz levels to the nearest tenth of a percent. This
is intended to be more protective for the miner than under the current
program of truncating results to the nearest full percent. We believe
that the method for establishing reduced standards will be more
protective for the miners than the current program.
Verification of Ventilation Plan Effectiveness.
Existing Sec. 75.370 requires you to develop an underground coal
mine ventilation plan that is designed to control methane and
respirable dust in the mine. It further requires that the plan be
suitable to the conditions and mining systems at the mine. Proposed
Secs. 70.201 to 70.211 sets forth the steps that MSHA will follow to
demonstrate that your mine ventilation plan required by Sec. 75.370 is
effective in controlling respirable dust under typical mining
conditions. This demonstration would be required before MSHA approves
the mine ventilation plan.
Under Secs. 70.201 to 70.211, MSHA would verify the effectiveness,
for the control of respirable dust, of all mine ventilation plans
submitted to the District Manager for approval under Sec. 75.370. To do
this, MSHA would collect full shift samples, called ``verification
samples.'' For MSHA to approve the plan, these samples would have to
demonstrate that the plan's dust control parameters are effective in
maintaining concentrations of respirable coal mine dust and quartz dust
in the working environment of MMUs at or below 2.0 mg/m\3\ and 100
<greek-m>g/m\3\, respectively, under typical mining conditions.
MSHA has drafted the regulatory text of this proposal in a question
and answer format. The remainder of the Section-by-Section discussion
also follows this format. As discussed in Chapter IV paragraph A below,
we request your comments on this format.
Section 70.201 Who must have a verified ventilation plan?
Section 75.370 requires all underground coal mine operators to
submit a mine ventilation plan for approval. The proposed Sec. 70.201
would require the verification of these plans in terms of their
effectiveness in controlling dust.
Section 70.202 What is a verified ventilation plan?
A ventilation plan submitted under Sec. 75.370 must be designed to
control respirable dust and must be suitable to the conditions and
mining systems at the mine. In order for the plan to be verified under
this proposal, the plan's dust control parameters must be demonstrated
to be effective, at a high level of confidence, in maintaining the
concentration of respirable coal mine dust and quartz dust in each MMU
at or below 2.0 mg/m\3\ and 100 <greek-m>g/m\3\, respectively. This
demonstration would be based on MSHA full shift verification samples,
which are collected when the amount of material produced is at or above
the VPL and only the engineering or environmental controls and other
measures included in the ventilation plan are in place, at levels not
exceeding 115% of the quantities specified in the plan.
Section 70.203 What will trigger the plan verification process?
There are several ways in which the plan verification process could
be initiated. You would trigger the process by submitting a new
ventilation plan under Sec. 75.370, or amending a previously approved
ventilation plan under Sec. 75.371(f). The verification process could
also be triggered if the District Manager requires you to change your
plan after determining that your dust control parameters are no longer
effective. Finally the verification process could be triggered if you
propose revisions to a previously verified ventilation plan and the
District Manager determines that the proposed revisions may cause the
plan to be inadequate.
Once your ventilation plan has been verified as effective, it
should not be necessary to reverify your plan every six months.
However, you may be required to change your plan parameters based on
(1) results of the MSHA six-month review of the ventilation plan as
required by Sec. 75.370(g), (2) excessive dust concentrations measured
by MSHA sampling, or (3) a new reduced applicable dust standard which
is less than the highest respirable coal mine dust concentration that
was previously used to verify the plan. For example, if you are cited
by MSHA for exceeding the applicable dust standard the District Manager
may have cause to question the adequacy of the previously-approved
plan.
Also, depending on sampling results and production records, if your
production exceeds the VPL during MSHA sampling, the District Manager
may require you to verify the ventilation plan at the higher production
level. For example, suppose your VPL is 10,000 tons and all five MSHA
concentration measurements exceed the applicable standard on a shift
for which the production is 12,000 tons. Then, if your production
records indicate that you have exceeded the VPL on more than 33 percent
of all production shifts during the previous six months, MSHA would
initiate the verification process.
Section 70.204 When will MSHA conduct verification sampling?
The District Manager will notify you of the schedule for
verification sampling after granting provisional approval of your
ventilation plan. However, before you receive provisional approval, you
may be required to change your plan if the District Manager determines
that your dust control parameters are inadequate or unsuitable for the
current mining conditions. If provisional approval is not granted, you
may not operate the affected MMUs. Since more than 700 existing mine
ventilation plans may require verification, MSHA will not be able to
verify all plans immediately. Under proposed Sec. 70.204 the District
Manager would notify you of the date when MSHA intends to collect
verification samples.
Section 70.205 What must I (the operator) do to comply this standard?
When the District Manager notifies you that your mine has been
scheduled for verification sampling, you would need to make sure that
all the dust control parameters specified in your ventilation plan are
fully implemented. Since the objective of plan verification is to
determine the effectiveness of the plan's dust control parameters in
controlling respirable dust under typical mining conditions, paragraph
(a) would require you to utilize only the dust control parameters
listed in the ventilation plan that was provisionally approved by the
District Manager. On the date scheduled for verification sampling, you
should establish production levels at or above the VPL specified in the
plan, using only the dust control parameters and other measures listed
in the plan.
[[Page 42144]]
Recognizing that engineering or environmental controls such as air
quantity and velocity are subject to measurement error and cannot
easily be controlled with absolute precision, MSHA would allow the
measured levels to be up to 115% of the levels specified in the plan.
If, on the date of verification sampling, a measured quantity exceeds
the corresponding quantity specified in the plan by more than 15
percent, you will have the option to either (1) adjust the parameter(s)
to what is specified in the plan before verification sampling begins or
(2) make no adjustment to the parameter(s) prior to verification
sampling. Under the second option, plan approval will be contingent on
incorporating into your plan the maximum values of parameters in effect
during verification sampling. If verification samples were taken when a
parameter measurement exceeded 115 percent of the level specified in
the plan, then (assuming none of the verification samples exceeded the
critical values) that parameter quantity, as measured, would be
incorporated in the plan ultimately approved by the District Manager.
As of the effective date of the final rule, you would be required
to begin maintaining records of the amount of material produced by each
MMU during each shift. This would enable you to establish the
``verification production level'' (VPL)--the minimum production level
at which you must demonstrate the plan's effectiveness.
Before you submit a previously approved ventilation plan to the
District Manager for review and approval, proposed paragraph (c) would
require you to provide additional information. This additional
information is described under Sec. 75.371(f) of this proposal.
To enable us to maximize our inspection resources and to promote an
orderly verification process, proposed paragraph (d) would require you
to notify the District Manager in a timely manner if you are unable to
meet the conditions for verification sampling on the scheduled date.
Failure to provide notification may be cause for revocation of the
provisional approval of your ventilation plan.
In accordance with section 103(f) of the Mine Act and the
recommendations of the Advisory Committee, miners and their
representatives would be provided the same walkaround rights during
plan verification sampling as they are provided during any other
physical inspection made pursuant to the provisions of section 103(a)
by an authorized representative of MSHA.
MSHA believes that under the guidance of the Interpretive Bulletin
(43 FR 17546, April 25, 1978) these rights arise when: (1) An
``inspection'' is made for the purposes set forth in section 103(a),
and (2) the inspector is physically present at the mine to observe or
monitor safety and health conditions as part of direct safety and
health enforcement activity.
The process of plan verification sampling is necessary to obtain
information related to approval of the mine's ventilation plan and
whether coal mine dust will be adequately controlled to protect miners
health. Consequently, miners and their representative would have the
right to accompany the inspector with no loss of pay for the time
during which the representative exercises this right. However, this
right is limited by Section 103(f) to only one such representative of
miners.
Section 70.206 Who will MSHA sample and where will MSHA place the
sampling device(s) when conducting verification sampling?
MSHA will sample specific occupations within an MMU to demonstrate
your plan's adequacy. These occupations would be selected because,
based on past experience, within an MMU they would likely be exposed to
the highest respirable coal mine dust concentration and, therefore,
would be at greatest risk of overexposure. Therefore, MSHA would sample
the environment of the DO (as under existing Sec. 70.207), the roof
bolter operator(s) (occupation codes--012, 014 or 046), the longwall
jack setters (occupation code--041), and any other occupation that the
District Manager may designate for sampling after reviewing your
ventilation plan.
Section 70.207 How many shifts will MSHA sample to verify my
ventilation plan?
This proposed section would explain that the number of shifts
required to verify your ventilation plan would depend on two factors:
first, the actual operating conditions during the shift that is
sampled; and, second, the sample results. To qualify as a verification
sample, the amount of material produced by the MMU must equal or exceed
the VPL, and the dust control parameters must be at levels not
exceeding 115 percent of the quantities specified in the plan.
Therefore, the number of shifts depends largely on how quickly and
consistently you are able to achieve these operating conditions. We may
need to sample several production shifts before the production level on
any single shift qualifies for verification purposes. We may verify the
plan based on this single shift--but only if all concentration
measurements on the sampled shift are at or below the appropriate
critical values proposed in Sec. 70.209. This would demonstrate the
plan's effectiveness at a high level of confidence. If any of the
measurements exceed the appropriate critical value, then we would
collect verification samples taken on one to three additional shifts,
depending on the concentrations measured on those shifts. Since these
additional shifts must also meet the criteria for production, and use
only the engineering or environmental controls and other measures
specified in the ventilation plan, we may have to sample a total of
more than four shifts.
Assuming that you make no special effort to meet the VPL during
verification sampling, there is a 67-percent probability that a
randomly selected production shift would not meet the VPL.
Consequently, if you made no special production effort, there would be
a 13-percent chance we would need to sample more than five shifts and a
1.7-percent chance we would have to sample more than 10 shifts. \8\ On
the other hand, again assuming no special production effort, there
would be a 98-percent chance we would need 10 or fewer shifts and a 70-
percent chance that we would need three or fewer shifts. \9\ This
assumes that the dust concentration measurement for each shift does not
exceed the critical value corresponding to the number of shifts
sampled. If you make a special effort to achieve high production on the
sampled shifts, then fewer shifts would be required.
---------------------------------------------------------------------------
\8\ Assuming no special production effort, the probability of
needing more than n shifts to be sampled before you met the minimum
production level required to verify the plan: P(X>n)= (.667) \n\;
for example, the probability of more than 10 shifts being needed,
P(X>10) = (.667) \10\ = 1.7 percent.
\9\ Assuming no special production effort, the probability of
needing n or fewer shifts to be sampled before you met the minimum
production level required to verify a plan:
P(X<ls-thn-eq>n)=1-P(X<gr-thn-eq>n); for example, the probability of
10 or fewer shifts being needed, (1-(.667) \10\) = 98 percent.
---------------------------------------------------------------------------
Section 70.208 What if 30 shifts of production data are not to
establish the verification production level (VPL)?
If you are starting a new MMU or mine, you may not have 30 shifts
of production data available when you submit a new ventilation plan. In
such cases, proposed Sec. 70.208 requires you to establish the VPL as
the minimum production level actually achieved on a shift used to
verify the plan's effectiveness. For example, assume we initiate
verification sampling of your longwall MMU. Based on the dust
[[Page 42145]]
concentration measurements obtained on the first shift sampled, your
MMU happens to exceed either 1.85 mg/m\3\ for respirable coal mine dust
or 93 <greek-m>g/m\3\ for quartz dust but not the verification limits.
According to the applicable critical values table in Sec. 70.209, we
would need to sample at least two more shifts to verify your plan's
effectiveness, provided that no sample exceed 1.93 mg/m\3\ for
respirable coal mine dust or 97 <greek-m>g/m\3\ for quartz dust. Assume
that the highest production level was achieved on the third shift
sampled and the dust concentration measurements obtained on that shift
were low enough, according to the applicable critical values table in
Sec. 70.209, to verify plan effectiveness based on a single shift. In
this case, you would establish a VPL equal to the production achieved
on that shift. If, on the other hand, the dust concentration
measurements obtained on the third shift with the highest production
level were not low enough to verify the plan on a single shift and a
determination of the plan's adequacy was based on these three shifts,
your VPL would be the minimum production achieved during verification
sampling. In any case, the VPL would become part of your ventilation
plan.
Section 70.209 When will MSHA approve my ventilation plan?
This is a new section that proposes ``critical values'' that the
District Manager would use to determine whether your plan's dust
control provisions should be approved. These critical values, which
differ according to the number of shifts used for verification, are
listed in Table IV-1. When verification sample results do not exceed
the appropriate critical value for respirable coal mine dust or quartz
dust, we can be confident that the engineering or environmental
controls in place during verification sampling successfully prevented
excessive dust concentrations at the sampled locations. Therefore, MSHA
would approve your plan when the dust control parameters are in place
during verification sampling and none of the measurements obtained from
your verification samples exceeded the appropriate critical value.
Appendix A explains how the critical values were derived.
Table IV-1.--Critical Values for Verifying Plan Effectiveness. The
Result of Each Verification Sample Collected Must Be Less Than or Equal
to the Appropriate Critical Value
------------------------------------------------------------------------
Critical Critical
value for value for
Number of shifts meeting criteria for coal mine quartz dust
verification sampling dust (mg/ (<greek-m>g/
m\3\) m\3\)
------------------------------------------------------------------------
1........................................... 1.71 87
2........................................... 1.85 93
3........................................... 1.93 97
4 or more................................... 2.0 100
------------------------------------------------------------------------
The proposed approval process would allow the District Manager to
base verification sampling on a reasonably small number of shifts,
while maintaining a high level of confidence that approved ventilation
plans adequately prevent excessive dust concentrations. We would have
to sample at least one full shift under the operating conditions
specified in the mine ventilation plan before we could make any
determination of the plan's adequacy. The plan would be approved if all
samples on that shift meet the criteria for a verification sample as
defined in Sec. 70.2, and none of the sample results exceed the
appropriate critical value for a single shift listed in Table IV-1.
However, if any verification sample resulted in a coal mine dust
measurement greater than 1.71 mg/m\3\ or a quartz dust measurement
greater than 87 <greek-m>g/m\3\, samples would be taken on additional
shifts.
The following two examples illustrate how we would determine if
your plan's dust control provisions should be approved:
Example 1: Suppose samples were taken on two shifts. We would
approve the dust control provisions of your plan if all quartz and
coal mine dust measurements obtained on the two shifts were less
than 1.85 mg/m\3\ or 93 <greek-m>g/m\3\, respectively. On the other
hand, if one of the roof bolter samples resulted in a quartz
concentration measurement of 95 <greek-m>g/m\3\, then we would not
approve your plan, based on these two shifts alone. Instead, at
least one additional shift would be needed. Verification samples
from only one additional shift would be sufficient if none of the
coal mine dust measurements on that shift exceeded 1.93 mg/m\3\, and
none of the quartz measurements exceeded 97 <greek-m>g/m\3\. (Dust
control parameters and production on this additional shift, as well
as on the first two shifts, would need to meet the criteria for
verification samples in proposed Sec. 70.2 (bb).)
Example 2: Suppose verification samples were taken on four or
more shifts. We would approve the dust control provisions as
proposed if no measurement exceeded 2.0 mg/m\3\ of coal mine dust or
100 <greek-m>g/m\3\ of quartz dust.
Section 70.210 What must I (the operator) do if one or more
verification samples exceed either verification limit?
This is a new section that would require you to take certain
actions whenever a verification sample results in a measurement
exceeding the verification limit for either respirable coal mine dust
(2.0 mg/m\3\) or quartz dust (100 <greek-m>g/m\3\). You would be
required to immediately identify the cause of the high dust
concentration and prevent miners from being overexposed on subsequent
shifts.
When you receive notice from MSHA that you have exceeded either
verification limit, you must immediately take corrective action. You
must lower excessive respirable dust concentrations, so that none of
your full shift measurements exceed verification limits in any of the
identified occupational environments or sampling locations. At the same
time, you must make approved respiratory equipment available to
affected miners in accordance with Sec. 70.300.
You would also be required to document the corrective actions taken
for the District Manager, within five days of MSHA's notification that
you have exceeded a verification limit. This documentation must
describe all of your corrective actions, including proposed changes in
dust control parameters. You would be encouraged to seek technical
assistance from the District Manager to help you determine what
additional corrective measures would be reasonably likely to reduce
excessive dust concentrations.
The District Manager will notify you if your ventilation plan is
provisionally approved and when MSHA will again commence verification
sampling. The District Manager may require you to make additional
changes in your plan parameter(s) based on the results of verification
sampling before starting sampling over again. If no changes are
required, MSHA will continue
[[Page 42146]]
verification sampling from the point at which it stopped.
The District Manager would choose, on a case-by-case basis, between
resuming verification sampling or starting plan verification anew. MSHA
would not necessarily require a revision of the ventilation plan nor
start the ventilation verification process over again because a
verification sample exceeded the verification limit by a small amount,
such as 0.05 mg/m\3\. The decision to continue with your current
ventilation plan or start over again with a new ventilation plan, would
be based on the information you provide regarding the cause of any
excessive dust concentration measurements and the steps you have taken
to prevent similar occurrences in the future. For example, suppose dust
concentration measurements are excessive due to a deviation in your
established operating procedures. It should be possible for you to
prevent such occurrences in the future without changing the ventilation
plan. If the District Manager finds this to be the case, and accepts
your proposed action to prevent similar occurrences, MSHA would resume
verification sampling. However, the District Manager may determine that
the ventilation plan is not adequate for current operating conditions
and require you to change the plan parameters. If so, MSHA would start
the verification sampling process over again.
MSHA would not issue citations for exceeding verification limits
during the plan verification process. However, MSHA will issue
citations under proposed Sec. 70.210(a) for failure to take action
required to address the cause of the excessive dust levels once you
have been notified by MSHA.
Section 70.211 What if verification samples continue to exceed either
verification limit even though I (the operator) believe all feasible
engineering and environmental controls are in place?
This proposed section would continue to require you to use all
feasible engineering or environmental controls before implementing any
supplemental means of control at longwall mining operations. For
continuous and conventional mining operations MSHA would suggest
additional engineering and environmental controls. Even if these
controls do not prevent full shift respirable dust concentrations from
exceeding the verification limits, you must continue to use them to
reduce respirable dust to the lowest feasible level. Engineering or
environmental controls have been the primary form of dust control for
the past 30 years. The Advisory Committee recommended that engineering
or environmental controls remain the primary means of protecting coal
miners. Consistent with the Mine Act and the Advisory Committee's
recommendation, under this proposal engineering or environmental
controls continue to be recognized the primary means to control
exposure to respirable dust.
If you operate an MMU employing either a continuous or conventional
mining method, we believe feasible engineering or environmental
controls are available to control respirable dust to an acceptable
level. Controls include better design of water spray systems for dust
suppression and air movement, use of dust collectors, and improved face
ventilation systems.
Of approximately 800 continuous miner MMUs operating in over 500
underground mines, over 90 percent employ extended cut techniques and
are being operated remotely (Elam, August 1999). As a result, the
continuous miner operator, the occupation normally identified as the DO
for bimonthly sampling purposes, is no longer required to work close to
the face area where material is being extracted.
Roof bolting machines, a major generator of respirable quartz dust
on continuous miner MMUs, must be equipped with suitable drill dust
controls. Under Sec. 72.630, drill dust must be controlled by
permissible dust collectors, by water, water with a wetting agent, by
ventilation, or by any other method approved by MSHA.
These and other approaches, as well as results of laboratory and
field studies of the effectiveness of various dust controls, can be
found in several detailed compilations prepared by the former U.S.
Bureau of Mines, whose responsibilities have now been transferred to
NIOSH. (U.S. Bureau of Mines various reports, undated). If you exceed
either verification limit, the District Manager will suggest that you
implement additional controls.
As discussed in section II. B., MSHA recognizes that improvements
in control technology have not kept pace with the increase in
production technology associated with high-production longwall MMUs.
Average longwall shift production reported during bimonthly sampling
has increased from 890 tons per shift in 1980, to over 4900 tons per
shift in 1999. Given the state of longwall dust control technology, the
currently-available engineering or environmental controls may not
succeed in sustaining continuous compliance at certain locations
downwind of the longwall operator (occupation code--044) at some high-
production longwall MMUs under typical mining conditions.
For your longwall operation, if you believe that you have
implemented all feasible engineering or environmental controls, you may
submit a written request to MSHA's Administrator for Coal Mine Safety
and Health in Arlington, Virginia, to request for MSHA to review your
longwall mining operation and determine if you have, in fact,
implemented all feasible engineering controls.
Upon receipt of such a request, MSHA would solicit guidance from a
panel of experts which would be established for making such
determinations. Members of this panel would have extensive knowledge in
respirable dust control and would represent the following organizations
within MSHA: Technical Support, Division of Health, the MSHA District
having jurisdiction over your mine, and one other MSHA District. In
some cases, we may solicit advice from NIOSH. As part of their
deliberations, the expert panel may visit your mine to observe the
various controls in operation. Any decisions reached by this panel
would be based on the review of available information, their combined
experience in dust control, and sound engineering judgement.
If the Administrator determines that you are using all feasible
engineering or environmental controls, we would notify you in writing
that you have been granted approval to use either PAPRs approved under
42 CFR 84 or verifiable administrative controls as a supplemental means
of control to protect miners required to work downwind of the longwall
operator. You would also be informed that the location of the DO would
be changed from the 060 to the 044 occupation, or other occupation
designated by the District Manager depending on how your longwall MMU
is ventilated. You must continue to maintain the work environment of
the new DO at or below the verification limits using engineering or
environmental controls, as demonstrated during plan verification. As
discussed earlier, while it may be difficult to make the environment
safe for some miners working on the longwall face under certain mining
conditions, MSHA believes that an acceptable work environment can be
provided for the longwall operator (occupation code--044) and other
miners on a continuing basis. You must choose either PAPRs or
verifiable administrative controls for your ventilation plan. The
notification would grant approval of an interim verification plan
allowing the use of PAPRs or administrative controls as a
[[Page 42147]]
supplemental means of compliance. You must introduce additional
engineering or environmental controls as they become available and
feasible. Every six months, as part of our regular review of your mine
ventilation plan, we would follow-up on your efforts to comply with
this requirement.
Sections 70.212 through 70.215
Use of Approved Powered, Air Purifying Respirators
These sections would establish the requirements for utilizing PAPRs
to supplement engineering or environmental controls.
Section 70.212 For my longwall operation, what must I (the operator)
do in order to use approved PAPRs to supplement engineering or
environmental controls?
This proposed section would require you to submit a revised
ventilation plan to MSHA within five days of receipt of MSHA's written
approval in accordance with Sec. 70.211 if you choose to use approved
PAPRs to supplement engineering or environmental controls. Your revised
plan must specify the engineering or environmental controls you believe
are capable of maintaining respirable dust concentrations (1) at or
below the verification limits in the environment of the new DO
(previously occupation 060, and currently occupation 044 or another
occupation designated by the District Manager), and (2) at or below two
times the verification limits in the environment of any miner working
on the longwall face (downwind of the DO) who is required to wear a
PAPR.
This is based upon the demonstrated effectiveness of PAPRs on
longwall MMUs and the range of longwall air velocities observed by MSHA
inspectors discussed earlier in section II.B.2, which led MSHA to
reduce the protection factor assigned to loose fitting, helmeted PAPRs
from 25 to two. In other words, the maximum full shift, MRE-equivalent
concentration of respirable dust allowed in the environment of any
miner working on the longwall face (downwind of the DO) who is required
to wear a PAPR cannot exceed 4.0 mg/m\3\ of respirable coal mine dust
and 200 <greek-m>g/m\3\ of respirable quartz dust.
In addition to specifying all feasible engineering or environmental
controls to be used, you would be required to include in your plan a
written respiratory protection program for PAPRs for all affected
miners as described in Sec. 72.710. MSHA's District Manager may require
you to modify the respiratory protection program before granting
provisional approval of your ventilation plan.
Once MSHA grants provisional approval, we will verify the
effectiveness of the revised dust control provisions of the ventilation
plan. We will sample the environment of the DO and of those miners that
your plan requires to wear approved PAPRs. If effectiveness of the plan
is verified, it would become your interim ventilation plan.
In order to continue using PAPRs for compliance purposes, you would
be required to maintain the effectiveness of your engineering or
environmental controls, as well as the effectiveness of your approved
PAPR respiratory protection program. We believe that the effectiveness
of a PAPR is dependent upon proper training and continued maintenance.
Training and maintenance procedures are part of an effective
respiratory protection program. The provision 30 CFR 72.710 requires
all respirators used in an underground coal mine to be selected,
fitted, used, and maintained in accordance with the provisions of the
American National Standards Institutes ``Practices for Respirator
Protection ANSI Z88.2-1969.'' These provisions include training miners
in the use and maintenance of respirators and the limitations of the
specific respirator worn. Necessary maintenance includes examining it
for defects prior to use, charging the batteries properly, and
appropriate replacement of parts including, but not limited to, the
filter elements, visors, batteries, blowers, and face seals.
Furthermore, all respiratory equipment used in an underground coal mine
must be approved by the National Institutes for Occupational Safety and
Health (NIOSH) under 42 CFR part 84.
The use of PAPRs is not intended to be permanent. Their use as a
supplemental control would be permitted only on an interim basis, until
feasible engineering or environmental controls become available. You
would have to implement any feasible engineering and environmental
controls, as they become available.
Section 70.213 For my longwall operation, when will MSHA approve my
interim ventilation plan incorporating a PAPR respiratory protection
program?
Approval of your interim mine ventilation plan would depend on the
results of verification sampling and the operating conditions in effect
for each sample. Paragraph (b) adds additional criteria or ``critical
values'' for coal mine dust and quartz dust to those specified in
Sec. 70.209. These additional critical values, listed in Table IV-2,
would apply to the environments of workers required to wear PAPRs under
the plan. The critical values given in Sec. 70.209 would continue to
apply to DO samples. However, once an interim ventilation plan is
approved, the position of the DO will change. Your plan would be
approved if it reflects the dust control parameters in place during
verification sampling and none of the verification samples exceed the
corresponding critical values. No DO dust sample obtained during the
verification process can exceed 2.0 mg/m\3\ (respirable coal mine dust)
or 100 <greek-m>g/m\3\ (respirable quartz dust). Since we estimate a
protection factor of two, no verification sample from the environment
where workers are required to wear PAPRs could exceed 4.0 mg/m\3\ (coal
mine dust) or 200 <greek-m>g/m\3\ (quartz dust).
Table IV-2.--Critical Values for Verifying Plan Effectiveness in the
Environment of Workers Required To Wear PAPRs. The Result of Each Sample
Used To Verify Plan Effectiveness for Such Work Environments Must Be
Less Than or Equal to the Appropriate Critical Value
------------------------------------------------------------------------
Critical
value for Critical
Number of shifts meeting criteria for coal mine value for
verification sampling dust (<greek- quartz dust
m>g/m\3\) (<greek-m>g/
m\3\)
------------------------------------------------------------------------
1........................................... 3.54 174
2........................................... 3.77 187
3........................................... 3.89 194
4 or more................................... 4.0 200
------------------------------------------------------------------------
[[Page 42148]]
Section 70.214 For my longwall operation, under what circumstances may
I (the operator) continue to use PAPRs to supplement engineering or
environmental controls?
In order to continue use of PAPRs to supplement your engineering or
environmental controls, you must comply at all times with the dust
control provisions of your interim mine ventilation plan. This
includes: (1) implementing and maintaining all feasible engineering or
environmental controls on each shift; and (2) complying with all
provisions of your approved PAPR respiratory protection program. In
addition, to ensure the continued effectiveness of your approved dust
control parameters, no DO sample taken by an MSHA inspector could
exceed the applicable dust standard. Furthermore, no MSHA measurement
for any miner working downwind of the DO could exceed twice the
applicable dust standard.
Finally, you would be required to continue to seek improvements and
implement, when they became available, any feasible engineering or
environmental controls. MSHA will follow-up on your efforts in this
regard as part of its regular six-month review of your mine ventilation
plan under Sec. 75.370.
Respirator programs require continuous administrative attention to
assure continued effectiveness. MSHA's District Manager would evaluate,
at least quarterly, the effectiveness of all installed engineering or
environmental controls, the effectiveness of your PAPR respiratory
protection program, and your performance in complying with all other
plan provisions.
Section 70.215 What if an MSHA DO sample exceeds the applicable dust
standard, or an MSHA sample for a miner required to wear a PAPR exceeds
twice the applicable dust standard.
This proposed section would require you to review your dust control
procedures and promptly take action which would prevent similar
occurrences in the future. Also, you must review your approved PAPR
respirator program to assure its continued effectiveness. Dust levels
in excess of the applicable standard could result from a change in
operating conditions, because of an abnormal condition or work
practice, or due to production exceeding the VPL. If you determine that
you cannot comply with the dust standard, you would need to amend your
interim ventilation plan and submit it to the District Manager for
review and approval.
If you are cited under Sec. 75.371 for failure to comply with your
approved interim plan, the District Manager may conduct an
investigation to determine if you are complying with the dust control
provisions of your approved interim ventilation plan. If the
investigation discloses that you are not following your plan, MSHA may
revoke approval of your plan.
Finally, the District Manager may revoke your interim plan and
withdraw permission to use PAPRs for compliance purposes if you have a
record of noncompliance with your interim ventilation plan, or if MSHA
samples indicate that miners are not adequately protected. If this
occurs, your revised interim plan must include a VPL at which you can
comply with the applicable standard.
Sections 70.216 Through 70.218
Use of Verifiable Administrative Controls
These sections establish requirements for using verifiable
administrative controls to supplement engineering or environmental
controls.
Section 70.216 For my longwall operation, what must I (the operator)
do in order to use verifiable administrative controls to supplement
engineering or environmental controls?
``Verifiable administrative controls'' are work practices that
reduce miners' daily exposure to respirable dust by altering the way in
which work is performed such as rotating miners to areas having lower
concentrations of respirable dust. To be considered verifiable
administrative controls, it is necessary that the practices: (1) Can be
reviewed to confirm proper implementation, (2) are clearly understood
by miners, and (3) can be applied consistently over time. If you choose
to use verifiable administrative controls for compliance purposes,
paragraph (a) requires you to submit a revised ventilation plan to
MSHA's District Manager within five days of receiving MSHA's written
approval in accordance with Sec. 70.211. This plan must specify: (1)
the feasible engineering or environmental controls to be used for
reducing respirable dust concentrations to the lowest possible level;
(2) the verifiable administrative controls to be implemented on the
longwall MMU; and (3) the procedures to be employed for ensuring
compliance with the verifiable administrative controls on every shift.
Once MSHA grants provisional approval, we will verify the
effectiveness of the revised dust control provisions of the ventilation
plan. We will sample all miners working on the longwall face, including
the DO (occupation code 044 or other occupation designated by the
District Manager), to demonstrate effectiveness of the proposed dust
control provisions. If effectiveness of the plan is verified, it would
become your interim ventilation plan.
The use of verifiable administrative controls is not intended to be
permanent. Their use for compliance purposes would be permitted only on
an interim basis, until feasible engineering or environmental controls
become available. You would have to implement any feasible engineering
and environmental controls, as they become available. You must make
sure that you continue to comply with your approved administrative
controls, and you must maintain the effectiveness of your engineering
or environmental controls. Finally, you must implement any feasible
engineering or environmental controls methods that become available,
and that would prevent full shift dust concentrations from exceeding
the applicable dust standard at any location at which miners normally
work at the longwall face.
Section 70.217 For my longwall operation, when will MSHA approve my
interim ventilation plan incorporating verifiable administrative
controls?
Approval of the dust control provisions of your interim ventilation
plan depends on the results of your verification samples and on the
actual operating conditions under which each sample was taken. None of
the samples obtained during the verification process may exceed 2.0 mg/
m\3\ (coal mine dust) or 100 <greek-m>g/m\3\ (quartz dust). Under
paragraph (b), MSHA's District Manager may approve the dust control
provisions of your interim plan if (1) the plan reflects all dust
controls, including administrative controls in effect during
verification sampling and (2) none of the samples used to verify plan
effectiveness exceed the appropriate critical values as specified and
explained in Sec. 70.209.
Section 70.218 For my longwall operation with an approved interim
ventilation plan, what if an MSHA sample exceeds the applicable dust
standard?
Under this section, you must immediately review your dust control
procedures, including the effectiveness of your administrative
controls, and take action to prevent similar occurrences in the future
if any MSHA compliance sample exceeds the applicable dust
[[Page 42149]]
standard. Dust levels in excess of the applicable standard could result
from a change in operating conditions, because of an abnormal condition
or work practice, or due to production levels which exceed the VPL. If
changes are made in your interim ventilation plan, you must submit them
to the District Manager for review and approval.
If you are cited under Sec. 75.371 for failure to comply with your
approved plan, the District Manager may conduct an investigation to
determine if you are complying with the dust control provisions of your
approved interim ventilation plan. If the investigation discloses that
you are not following your plan, approval of your plan may be revoked.
Finally, the District Manager may revoke your interim plan and
withdraw permission to use administrative controls for compliance
purposes if you have a record of noncompliance with your interim
ventilation plan, or if MSHA samples indicate that miners are not
adequately protected. If this occurs, your revised interim plan must
include a VPL at which you can comply with the applicable standard.
Actions Necessary When You Are in Violation of Respirable Dust
Standards
Section 70.219 What must I (the operator) do if I am cited for
exceeding the applicable dust standard?
If you are cited for violating Sec. 70.100 or Sec. 70.101, you
would be required to promptly review your dust control practices to
determine the cause of the excessive dust concentration. You would also
be required to take corrective action to prevent miners from being
overexposed in the future by lowering the concentration of respirable
dust to comply with the applicable dust standard. You would be required
to take these actions within the abatement period fixed in a citation.
After reviewing your dust control practices and taking corrective
action, you would be required to incorporate changes reflecting these
actions into your ventilation plan in accordance with
Sec. 75.370(a)(2). If, in your opinion, the corrective actions taken do
not warrant a change in your plan's dust control parameters, you would
need to explain that in your response to the District Manager. This
will enable the District Manager to determine if the ventilation plan
should be changed and re-verified.
Based on the dust parameters that were in use for the results of
the compliance sample(s) dust concentrations measured by MSHA samples,
and the information submitted by the operator regarding the type(s) of
corrective action that were taken, MSHA may elect to sample the cited
entity to determine the effectiveness of your abatement actions. If
these samples indicate compliance with the applicable dust standard,
you would be required to incorporate your corrective actions in your
mine ventilation plan. At a minimum you would be required to
incorporate in your plan the actual parameters that were in effect when
MSHA sampled. If the MSHA samples indicate continued noncompliance,
then MSHA may revoke approval of your ventilation plan.
Information To Be Posted on the Mine Bulletin Board
Section 70.220 What information must I (the operator) post on the mine
bulletin board?
This proposed section would provide ready access to current
information relating to the plan verification process and to the
respirable dust conditions in the mine. You would be required to post
on the mine bulletin board the actual values of specific dust control
parameters measured by MSHA on shifts used for plan verification and
all sample results. For the same reason, the proposal would require
that all written notifications received from the District Manager
regarding any aspect of the plan verification process. You could remove
the information from the mine bulletin board after the plan is approved
by the District Manager.
Also, you would also be required to post the results of MSHA
compliance sampling on the bulletin board. These results must be posted
for at least 31 days. These posting requirements are intended to
promote miner awareness of the conditions under which the mine
ventilation plan has been shown to be effective in controlling dust
levels in their work environment. The goal is consistent with the
statutory intent that miners play a role in preventing unhealthy
conditions and practices where they work.
Status Change Reports
Section 70.221 What action must I (the operator) take if the
operational status of my mine, MMU, or DA changes?
In order to conduct verification and compliance sampling, it is
essential that you provide current information to us concerning the
production status of MMUs and DAs within those mines that are in
producing status. Therefore, to reduce the chances of visiting a mine
whose operating status prevents the MSHA inspector from sampling, you
would continue to be required to report the change in operational
status of the mine, MMU, or DA to the MSHA District Office or to any
other MSHA office designated by the District Manager. You would also be
required to report a change in operational status if it would affect
the verification sampling requirements under this proposal. Status
changes would be reported in writing within three working days after
the status change occurred. The reporting of changes in operational
status is not a new requirement and is contained in existing
Sec. 70.220. MSHA is renumbering existing Sec. 70.220 as Sec. 70.221.
Changes to Part 75
Section 75.370 Mine Ventilation Plan; Submission and Approval
This proposal would amend Sec. 75.370 by adding a new paragraph
(h). Paragraph (h) would require that records of the amount of material
produced each production shift by each MMU during the previous six-
month period be made available for inspection by authorized
representatives of the Secretary and the miners' representative.
These records are essential for the plan verification process. The
records are needed to establish the verification production level (VPL)
required under proposed Sec. 75.371(f) and to confirm that the 30-shift
period on which the VPL is based represents typical production
conditions for the MMU. Additionally, MSHA and the miners'
representative need these records to monitor changes in production
levels that may affect the plan's adequacy. Finally, because
verification of a plan's effectiveness is conditioned on the VPL, these
records are necessary to determine if the VPL used in approving a plan
continues to reflect typical production levels at the mine.
The production records for each MMU may be maintained in any form
utilized by the operator to measure the total amount of material
produced, so long as the method is the same as that used to establish
the VPL required for plan verification. For example: number of loaded
shuttle cars, feet of advance, raw tonnage, or number of longwall
passes would each be an acceptable method of recording production--so
long as the same method was consistently used.
Section 75.371 Mine Ventilation Plan; Contents
The proposal would revise paragraphs (f) and (t). Existing
paragraph (f) would be revised to require the ventilation plan to
include any specific work practices used to minimize the dust
[[Page 42150]]
exposure of individual miners, information on the location of the roof
bolter(s) during the mining cycle for each continuous miner section,
and the cut sequence for each longwall mining section.
Also, every ventilation plan would be required to include
information on the length of each normal production shift and to
specify the VPL as defined in Sec. 70.2. Although a VPL would be
included in the ventilation plan, MSHA would not cite you for producing
at levels exceeding the VPL. We would expect production on an MMU to
exceed the VPL on about 33 percent of all production shifts. If the
District Manager determines that your production exceeds the VPL on
more than 33 percent of the production shifts over a six-month period,
then this may trigger the plan verification process using a higher VPL.
For interim plans involving the use of powered, air purifying
respirators (PAPRs) or verifiable administrative controls, the plan
must also include the information respectively required under
Sec. 70.212(b) or Sec. 70.216(a). This additional information is
necessary to fully assess the adequacy of mine ventilation plans.
Since MSHA is proposing to revoke existing Secs. 70.207 and 70.208
which require sampling by mine operators, existing paragraph (t) would
be revised to remove the provision that mine operators identify in the
mine ventilation plan the locations where samples for designated areas
(DA) will be collected, including the specific location of each
sampling requirement, and the reference to Sec. 70.208. However, to
ensure that the mine atmosphere where miners are normally required to
work or travel is continuously maintained in compliance, proposed
paragraph (t) would continue to require mine operators to identify in
the mine ventilation plan the location of each DA, defined in proposed
Sec. 70.2(e), and the particular dust control measures that would be
used at the dust generating sources for these locations. These
locations would continue to be sampled by MSHA inspectors as discussed
earlier (see Background Section) to determine compliance with the
applicable standard and to assess the adequacy of the operator's dust
control measures.
Part 90
The proposed rule would revoke all operator sampling requirements
associated with coal miners who have evidence of the development of
pneumoconiosis under Part 90. MSHA is republishing the entire
regulatory text of Part 90 as it would appear under the proposal for
ease of review. Aside from a few technical clarifications which are
described below, the only change to Part 90 would be to remove all
references to operator sampling.
Section 90.1 Scope.
The scope of part 90 would not change under the proposal. However,
the phrase ``including respirable dust sampling for Part 90 miners''
would be removed from the end of the sentence which states that ``the
rule also sets forth the operator's obligations.''
Section 90.2 Definitions.
All definitions would remain unchanged under the proposal with the
exception of those for ``concentration'' and ``mechanized mining unit''
which have been clarified as described below. The definition for
``valid respirable dust sample'' would be removed because mine
operators would no longer collect Part 90 samples under the proposal.
No discussion has been included below if the definition would not
change under the proposal. For ease of reference, subsection references
have been added for each definition.
Concentration is a measure of the amount of substance contained per
unit volume of air.
The existing definition would be modified so that ``concentration''
refers to an 8-hour Mining Research Establishment (MRE) equivalent
measure of the amount of sampled material contained per unit volume of
air. The proposed revision would include the constant factor of 1.38
which the Secretary currently uses to convert concentration of
respirable dust measured with approved sampling devices to an
equivalent concentration as measured with an MRE instrument.
The existing coal mine dust standards were developed from 8-hour
shift exposure measurements. Therefore, if a sample is taken over a
period other than eight hours, the concentration measurement must be
adjusted to be equivalent to an eight-hour exposure. This is necessary
in order to provide equal protection to miners working shifts greater
than eight hours and would be accomplished by multiplying the sampler
flow rate by 480 minutes, regardless of the length of time that the
sample was actually collected.
For this example, suppose a DO sample is collected over a 9-hour
shift that includes one hour of travel time. Suppose that the amount of
dust accumulated during travel is negligible, and the amount
accumulated during production is 1.5 mg. If the concentration were not
adjusted to an 8-hour equivalent, it would be diluted by the time spent
traveling and calculated as 1.92 mg/m\3\. Under the proposed
definition, the calculated concentration would be 2.16 mg/m\3\.
The proposed definition does not change the daily limit on
accumulated exposure intended by the existing exposure limit for coal
mine dust. Since the current limit was based on an assumption that
exposure occurs over an 8-hour shift, it corresponds to a daily
cumulative exposure limit of 8 x 2.0 = 16 mg-hr/m\3\. The proposed
definition of concentration would maintain this same MRE-equivalent 16
mg-hr/m\3\ daily limit, regardless of the length of any shift worked.
To continue the example, the exposure accumulated during a day is
the same, whether from 8 hours at an average of 2.16 mg/m\3\ or from 9
hours at an average of 1.92 mg/m\3\. In either case, the MRE-equivalent
exposure accumulated for the day is 17.3 mg-hr/m\3\, which exceeds the
intended daily limit of 16 mg-hr/m\3\. Under the proposed definition,
this would be reflected by the fact that the calculated concentration
exceeds 2.0 mg/m\3\. MSHA solicits comments on this method of adjusting
concentrations to an 8-hour equivalent.
Mechanized mining unit has been revised to refer to the proposed
rule new Sec. 70.205. The definition also clarifies that each MMU is
assigned a four digit identification number by MSHA. The MMU retains
the identification number regardless of where the unit relocates within
the mine. When two sets of mining equipment are provided in a series of
working places and only one production crew is employed at any given
time on either set of mining equipment, the two sets of equipment are
to be identified as a single MMU. When two or more MMUs are
simultaneously engaged in the production of material within the same
working section, each such MMU is identified separately.
Section 90.100 Respirable dust standard.
The Part 90 respirable dust standard would not change. Since MSHA
would collect all Part 90 samples under the proposal, the sentence
which provides that ``concentrations shall be measured with an approved
sampling device and expressed in terms of an equivalent concentration
determined in accordance with Sec. 90.206'' would be removed.
Section 90.101 Respirable dust standard when quartz is present.
Because MSHA would collect all Part 90 samples, this section would
be
[[Page 42151]]
changed by removing the sentence which provides that ``concentrations
shall be measured with an approved sampling device and expressed in
terms of an equivalent concentration determined in accordance with
Sec. 90.206.''
An example has been added to explain how a reduced standard is
established when respirable dust associated with a part 90 miner
contains quartz in the amount of 20%.
Section 90.102 Transfer; notice.
This section would remain unchanged.
Section 90.103 Compensation.
This section would remain unchanged.
Section 90.104 Waiver of rights; re-exercise of option.
This section would remain unchanged.
Section 90.201 MSHA Respirable dust sample reports; Operator status
change reporting requirement.
Under the proposal, mine operators would no longer collect
respirable dust samples under Subpart C of Part 90. Consequently, all
of Subpart C, ``Sampling Procedures,'' including Secs. 90.201-209 would
be removed. Existing Sec. 90.210 would be renumbered as Sec. 90.201.
The requirements of this section would remain unchanged.
Section 90.202 Operator status change reports.
Under the proposal, mine operators would no longer collect
respirable dust samples under Subpart C of Part 90. Consequently, all
of Subpart C, ``Sampling Procedures,'' including Secs. 90.201-209 would
be removed. Existing Sec. 90.220 would be renumbered as Sec. 90.202.
The requirements of this section would remain unchanged.
Section 90.300 Respirable dust control plan; filing requirements.
There would be no change in the filing requirements for respirable
dust control plans under the proposal.
Section 90.301 Respirable dust control plan; approval by District
Manager; copy to part 90 miner.
There would be no change in the approval process or notice
requirements for respirable dust control plans under the proposal.
V. Health Effects
A. Introduction
Since the 1800s, occupational respiratory disease associated with
working in a coal mine has been commonly referred to as ``Black Lung.''
As coal is mined, respirable-sized dust is generated. Depending upon
the mine location and its geologic features, silica may also be present
in the mine atmosphere. Dust in air that is breathed by miners has the
potential to be deposited in their lungs. Some of this dust may be
retained. Coal mine dust remaining in the lungs of miners for prolonged
periods of time has the potential to result in respiratory diseases,
sometimes even after occupational exposure to respirable coal mine dust
has stopped. There is a clear and direct relationship between miners'
cumulative exposures (i.e., dose multiplied by the time exposed to the
coal mine dust) to respirable coal mine dust and the severity of
resulting respiratory conditions (as discussed more extensively, later
in this section).
Diseases resulting from long-term retention of coal mine dust in
the lung include chronic coal workers' pneumoconiosis (simple CWP),
progressive massive fibrosis (PMF), silicosis, and chronic obstructive
pulmonary disease (COPD) (e.g., asthma, chronic bronchitis, emphysema).
Historically, the medical term, ``pneumoconiosis,'' has included simple
CWP and PMF and their sub-categories. Chronic, or simple, CWP is
partitioned into three levels of severity, proceeding from lowest to
highest: category 1, category 2, and category 3. Progressive Massive
Fibrosis is similarly divided into three categories of increasing
levels of severity: A, B and C.
Miners with simple CWP have a substantially increased risk of
developing PMF. In the advanced stages of pneumoconiosis (i.e., PMF), a
significant loss of lung function may occur and respiratory symptoms
(e.g., breathlessness, wheezing) may persist. Miners are at risk of
increased morbidity and premature mortality due to simple CWP, PMF and
various other respiratory diseases.
Factors that are important in the development of simple CWP, PMF
and COPD include the type of dust (e.g., coal and/or silica), dust
concentration (to which the miner was exposed), number of years of
exposure, age of the miner (often measured as age at time of medical
examination), and rank of the coal (the higher the rank the greater the
risk).
In 1998, MSHA estimated that approximately 45,000 miners and 39,000
miners were employed at underground and surface coal mines,
respectively (Mattos, 1999). A small percentage of the mining involved
anthracite coal, the highest rank coal, while most involved bituminous
coal which is a medium rank coal.
There are complementary data sources, described below, which
provide estimates of the prevalence of occupational respiratory disease
among coal miners. Together these data demonstrate the progress over
the last thirty years in the reduction of occupational respiratory
disease among coal miners, as well as the need for further action to
reduce occupational lung disease among today's coal miners.
Estimates of the prevalence of simple CWP and PMF among the
underground coal miners are gathered from the x-ray program, through
which operators are required to provide miners the opportunity to be
evaluated periodically for the presence of occupational lung disease,
mandated pursuant to Section 203(a) of the Mine Act (30 U.S.C. 843(a)).
However, miners are not required to participate. From 1970 to 1995, the
prevalence of simple CWP and PMF among miners participating in the
mandated x-ray program has dropped from 11 percent to 3 percent (MSHA,
Internal Chart, 1998).
In accordance with 30 CFR part 50, those cases of occupational
illnesses which both surface and underground coal mine operators learn
of must be reported to MSHA. Under this requirement, mine operators
reported 224 cases of pneumoconiosis (simple CWP and PMF, combined) in
1998 (Mattos, 1999). Of these, 138 cases occurred among coal miners who
worked underground, while the remaining 86 cases occurred among surface
coal miners (Mattos, 1999). There were also 14 cases of silicosis,
eight in underground mines, reported to MSHA in 1998 in accordance with
30 CFR part 50 (Mattos, 1999). Since miners participate in both these
programs at their own discretion, these data do not include the
occupational health experience of all coal miners. The prevalence of
occupational lung disease among participating miners may significantly
differ from the prevalence among non-participants. Thus, the data from
these programs may not be representative of the true magnitude of the
prevalence of simple CWP and PMF among today's coal miners.
In the 1990s, MSHA conducted a series of one-time medical
surveillance programs, in various regions of the country, to develop a
more accurate estimate of the prevalence of simple CWP and PMF. Through
these special programs, MSHA tried to minimize obstacles which may
prevent some miners from either participating in or reporting to
operators the results of respiratory diagnostic procedures. Nine
[[Page 42152]]
geographical cohorts of miners, from around the country, were
encouraged to participate in an independent x-ray program (MSHA,
Internal Chart, 1999). These cohorts included eight active surface coal
mining communities in the states of Pennsylvania, Kentucky and West
Virginia, as well as the towns of Poteau, Oklahoma and Gillette,
Wyoming. A ninth cohort included underground miners in Kentucky. The
process was designed to encourage miner participation by providing for
a greater degree of anonymity than may be available under the program
provided by Section 203(a) of the Mine Act (30 U.S.C. 843(a)). Across
the eight surface cohorts surveyed, the prevalence rate of simple CWP
and PMF combined, among participants was 4.8%. The prevalence rate
among the participating underground Kentucky miners was 9.2%.
Also, as part of its ongoing effort to ``end black lung now and
forever,'' beginning in October 1999, MSHA implemented a pilot program
to provide miners at both surface and underground mines with
confidential health screening. Referred to as the ``Miners' Choice
Health Screening,'' the program addresses the key recommendations of
the Secretary's Advisory Committee by (1) increasing participation
toward the 85-percent level and (2) expanding the scope of the
eligibility to include surface coal miners and surface coal mine
independent contractors. The pilot program operates separately from the
existing Coal Workers' X-ray Surveillance Program administered by
NIOSH. Since the Miners' Choice Health Screenings' inception, over
7,000 miners have been screened, with the participation rate in most
areas exceeding 50 percent. With half of the x-rays taken during the
first six months having been processed by NIOSH, preliminary results
indicate a prevalence rate of approximately 2.25 percent.
The National Institute for Occupational Safety and Health (NIOSH)
and the Mine Safety and Health Administration (MSHA) are concerned
about the prevalence of occupational lung disease among today's miners.
Epidemiological studies from the U.S. and abroad have consistently
shown that underground and surface coal miners are at risk of
developing simple CWP, PMF, silicosis, and chronic obstructive
pulmonary disease (NIOSH Criteria Document, 1995).
B. Hazard Identification
1. Agent: Coal
Coal is a fossil fuel derived from partial degradation of
vegetation. Through its combustion, energy is produced which makes coal
a valuable global commodity. It has been estimated that over one-third
of the world uses energy provided by coal (Manahan, 1994).
Approximately 1,800 underground and surface coal mines are in operation
in the United States annually producing slightly over a billion short
tons of coal (Mattos, 1999).
Coal may be classified on the basis of its type, grade, and rank.
The type of coal is based upon the plant material (e.g., lignin,
cellulose) from which it originated. The grade of coal refers to its
chemical purity. Although coal is largely carbon, it may also contain
other elements such as hydrogen, oxygen, nitrogen, and sulfur. ``Hard''
coal refers to coal with a higher carbon content (i.e., 90-95%) than
``soft'' coal (i.e., 65-75%). Coal rank relates to geologic age,
indexed by its fixed carbon content, down to 65%, and then by its
heating value. Volatile matter varies inversely with the fixed carbon
value. The most commonly described coal ranks include lignite (low
rank), bituminous coal (medium rank), and anthracite (high rank)
(Manahan, 1994).
2. Physical State: Coal Mine Dust
Aerosols are a suspension of solid or liquid particles in air
(Mercer, 1973); they may be dusts which are solid particles suspended
in the air. Coal dust may be freshly generated or may be re-suspended
from surfaces on which it is deposited in mines. As discussed below,
coal mine dust may be inhaled by miners, depending upon the particle
size.
Coal mine dust is a heterogenous mixture, signifying that all coal
particles do not have the same chemical composition. The particles are
influenced by the type, grade, and rank of coal from which they were
generated (Manahan, 1994). Irrespective of differences in coal
characteristics, these dusts are water-insoluble, which is important
biologically and physiologically. Unlike soluble dusts which may
readily pass into the respiratory system and be cleared via the
circulatory system, insoluble dusts may remain in the lungs for
prolonged periods of time. Thus, a variety of cellular responses may
result that could eventually lead to lung disease.
3. Biological Action: Respirable Coal Mine Dust
The principal route of occupational exposure to respirable coal
mine dust occurs via inhalation. As a miner breathes, coal mine dust
enters the nose and/or mouth and may pass into the mid airways (e.g.,
bronchi, terminal bronchioles) and lower airways (e.g., respiratory
bronchioles, alveolar ducts).
Coal mine dust has a size distribution that is estimated to range
between 1 and 100 micrometer (<greek-m>m) (1 <greek-m>m =
10<SUP>-</SUP>\6\ m) (Silverman, et al., 1971). The size of coal
particles is critical in determining the level of the respiratory tract
at which deposition and retention occur (American Conference of
Governmental Industrial Hygienists, 1999; American Industrial Hygiene
Association, 1997).
Particles that are above 10 <greek-m>m are largely filtered in the
nasal passages, although some of these particles may reach the thoracic
(or tracheal-bronchial) region of the lung (e.g., 6% of 20 <greek-m>m)
(American Conference of Governmental Industrial Hygienists, 1999).
Thus, there is evidence that ``oversized'' particles (i.e., >10
<greek-m>m) can move beyond the nose, deeper into the respiratory
tract. Particles below 10 <greek-m>m may easily move throughout the
respiratory tract. As particle size decreases from 10 to 5 <greek-m>m,
however, there is greater penetration into the mid and lower regions of
the lung. Particles that are approximately 1-2 <greek-m>m are the most
likely to be deposited in the lung (American Conference of Governmental
Industrial Hygienists, 1999; Mercer, 1973). During mouth breathing,
there may be a slight upward shift in the particle deposition curve
such that 2-3 <greek-m>m-sized particles are the most likely to be
deposited in the respiratory tract (Heyder, et al., 1986). Irrespective
of nasal or mouth breathing, the potential respiratory tract
penetration of particles whose size is approximately 10 <greek-m>m or
less is important because particles in the respirable size range
deposit in the deep lung where clearance is much slower.
For the purposes of this rule, ``respirable dust'' is defined as
dust collected with a sampling device approved by the Secretary of
Labor and the Secretary of the Department of Health and Human Services
(DHHS) in accordance with 30 CFR Part 74 (Coal Mine Dust Personal
Sampler Units). In practice, the coal mine dust personal sampler unit
has been used in the U.S. The particles collected with an approved
sampler approximate that portion of the dust which may be deposited in
the lung (West, 1990; 1992). It does not, however, indicate pulmonary
retention (i.e., those
[[Page 42153]]
particles remaining in the lung). For those particles that are
deposited in the lung, clearance mechanisms normally operate to assist
in their removal. For example, within the thoracic (tracheal-bronchial)
region of the lung, cilia (i.e., hairlike projections) line the airways
and are covered by a thin layer of mucus. They assist in particle
clearance by beating rhythmically to project particles toward the
throat where they may be swallowed, coughed, sneezed, or expectorated.
This rhythmic beating action is effective in removing particles fairly
quickly (i.e., hours or days). Within the alveolar region of the lung,
particles may be engulfed by pulmonary macrophages. These large
``wandering cells'' may remove particles via the blood or lymphatics.
This process, unlike the movement of the cilia is much slower (i.e.,
months or years). Thus, some particles, particularly those that are
insoluble, may remain in the alveolar region for long periods of time,
despite the fact that pulmonary clearance is not impaired. It is the
pulmonary retention of coal mine dust which may be the impetus for
respiratory disease.
It is also important to note that silica may be present in the coal
seam, within dirt bands in the coal seam, and in rock above and below
coal seams. Of the silica found in coal mines, quartz is the form which
is found. Thus, quartz may become airborne during coal removal
operations (Manahan, 1994). Miners may inhale dust that is a mixture of
quartz and coal. MSHA is concerned with the inhalation of quartz since
it may be deposited in the lungs of miners and produce silicosis. This
is a restrictive lung disease which is characterized by a stiffening of
the lungs (West, 1990; 1992). Silicosis has been seen in coal miners
(e.g., surface miners, drillers, roofbolters) (Balaan, et al., 1993).
Silicosis may develop acutely (i.e., 6 months to 2 years) following
intense exposure to high levels of respirable crystalline quartz.
Silicosis has also been observed in coal miners following chronic
exposure (i.e., 15 years or more), but may be accelerated (i.e., 7-10
years) in some cases (Balaan, et al., 1993). Silicosis is irreversible
and may lead to other illnesses and premature mortality. People with
silicosis have increased risk of pulmonary tuberculosis infection and
an increased risk of lung cancer (Althouse, et al., 1995; International
Agency for Research on Cancer, 1997). MSHA's current standard of 2.0
mg/m\3\ for respirable coal dust requires that quartz levels be 5% or
lower. Otherwise, the 2.0 mg/m\3\ respirable coal dust exposure limit
does not apply and must be adjusted downward for percent quartz. If
coal dust contains more than 5% quartz, then the following formula is
applied (30 CFR 70.101; 30 CFR 71.101):
Respirable dust standard (mg/m\3\) = [(10 mg/m\3\)/(%Quartz)]
The intent of this formula is to maintain miner exposures to quartz
below 0.1 mg/m\3\ (100 <greek-m>g/m\3\).
C. Health-Related Effects of Respirable Coal Mine Dust
1. Description of Major Health Effects
Consistently, epidemiological studies have demonstrated miners to
be at risk of developing respiratory symptoms, a loss of lung function,
and lung disease as a consequence of occupational exposure to
respirable coal mine dust. As noted previously, risk factors include
type(s) of dust, dust concentration, duration of exposure, age of the
miner (often measured as age at time of medical examination), and coal
rank.
a. Simple Coal Workers' Pneumoconiosis (Simple CWP) and Progressive
Massive Fibrosis (PMF). In earlier stages of pneumoconiosis the term,
``simple coal workers' pneumoconiosis'' (simple CWP), has been used,
while in more advanced stages, the terms ``complicated CWP'' and PMF
have been used interchangeably. Simple CWP and PMF involve the lung
parenchyma and are produced by deposition and retention of respirable
coal dust in the lung.
To determine if a miner has simple CWP or PMF, chest x-rays are
taken and classified by a certified radiologist or reader. Opacities
are identified on chest films and then classified using a scale of 0-3
(e.g., simple CWP category 1), where higher category values indicate
increasing concentration of opacities. In some instances, two category
values may be given. For example, simple CWP category \2/3\ signifies
that the reader decided the film was category 2, but suspected that it
might have been category 3. The International Labour Office (ILO) has
provided a full description of the criteria for these classifications
(ILO, 1980).
Simple CWP can be associated with a loss of lung function and with
premature mortality (Morgan, et al., 1974; Jacobsen, 1976; Cochrane, et
al., 1979; Parkes, 1982). MSHA recognizes that simple CWP increases the
risk of developing PMF substantially (Cochrane, 1962; Jacobsen, et al.,
1971; McLintock, et al., 1971; Balaan, et al., 1993).
Progressive massive fibrosis (PMF) is associated with decreased
lung function and increased premature mortality (Rasmussen, et al.,
1968; Atuhaire, et al., 1985; Miller and Jacobsen, 1985; Attfield and
Wagner, 1992). Progressive massive fibrosis is also associated with
increases in respiratory symptoms such as chest tightness, cough, and
shortness of breath. Miners with PMF also have an increased risk of
acquiring infections and pulmonary tuberculosis (Petsonk and Attfield,
1994; Yi and Zhang, 1996). Finally, miners with PMF have an increased
risk of right-side heart failure (i.e., cor pulmonale) (Cotes and
Steel, 1987).
b. Other Health Effects. During a medical examination, a miner may
be questioned by his physician about symptoms such as cough, phlegm
production, chest tightness, shortness of breath, and wheezing.
Occupational physicians may also conduct pulmonary function tests using
spirometry or plethysmography. Pulmonary performance may be assessed
via repeated measurements of lung volumes and capacities, such as the
forced expiratory volume in one second (FEV<INF>1</INF>), vital
capacity (VC), forced vital capacity (FVC), residual volume (RV), and
total lung capacity (TLC) (West, 1990; 1992). Changes in lung volumes
and capacities may indicate a loss of the integrity of the lung (i.e.,
respiratory system). More importantly, they can provide information for
diagnosis of diseases affecting the airways and/or elasticity of the
lung (i.e., obstructive vs. restrictive lung disease)(West, 1990;
1992).
The term, chronic obstructive pulmonary disease (COPD), refers to
three disease processes that are often difficult to properly diagnose
and differentiate: chronic bronchitis, emphysema, and asthma (Coggon
and Taylor, 1998; Garshick, et al., 1996; West, 1990; 1992). As
indicated by several studies, the exposure of miners to respirable coal
mine dust place them at increased risk of developing COPD. Furthermore,
COPD may occur in miners with or without the presence of simple CWP or
PMF.
Chronic Obstructive Pulmonary Disease (COPD) is characterized by
airflow limitations, and thus there is a loss of pulmonary function. As
in simple CWP or PMF, a miner with COPD may have a variety of
respiratory symptoms (e.g., shortness of breath, cough, sputum
production, and wheezing) and may be at increased risk of acquiring
infections. Chronic Obstructive Pulmonary Disease is associated with
increased premature mortality (Hansen, et al., 1999; Meijers, et al.,
1997).
Briefly, in chronic bronchitis and in asthma, there is excess
mucous
[[Page 42154]]
secretion in the mid-lower airways (West, 1990; 1992). In contrast,
emphysema is characterized by dilatation (enlargement) of alveoli that
are distal to the terminal bronchioles, which leads to poor gas
exchange (i.e., poor transfer of oxygen and carbon dioxide).
Additionally, there is a breakdown of the interstitium between the
alveoli. These pathological changes may be confirmed upon autopsy. With
asthma, the airflow limitations may be partially or completely
reversible, while they are only partially reversible with chronic
bronchitis and emphysema.
The Mine Safety and Health Administration (MSHA) and the NIOSH
recognize that respiratory symptoms, loss of lung function, and COPD
may impair the ability of a miner to perform his job and may diminish
his quality of life. Additionally, miners having such health effects
are at increased risk of morbidity (e.g., from cardio-pulmonary
disease, infections) and premature mortality.
2. Toxicological Literature
To better understand the human health effects of exposure to
respirable coal mine dust and to more fully characterize the associated
risks, it is important to consider data that have been obtained in
animal based toxicological studies. To date, sub-acute studies (a study
with a duration of 30 days, or less, in which multiple exposures of the
same agent are given) and chronic studies (a study with a duration of
more than 3-months, in which multiple exposures of same agent are
given) attempted to mimic miners' exposures. Inhalation was generally
the route of exposure, although several studies have also employed
instillation techniques (i.e., a method which places a known quantity
of dust into the trachea or bronchi).
Most recent toxicological studies have been short-term studies,
largely focusing on ``lung overload'' (Sipes, 1996; Oberdorster, 1995;
Morrow, 1988, 1992; Witschi, 1990), species-dependent lung responses
(Nikula, et al., 1997a,b; Mauderly, 1996; Lewis, et al., 1989; Moorman,
et al., 1975), and particle size-dependent lung inflammation (Soutar,
et al., 1997). The data have shown that pulmonary clearance of
particles may become impaired, potentially leading to inflammatory and
other cellular responses in the lung. Although overloading has not been
demonstrated in humans, the finding of reduced lung clearance among
retired U.S. coal miners (Freedman and Robinson, 1988) is consistent
with this possibility.
The data from Moorman, et al. (1975), Lewis, et al. (1989), and
Nikula, et al. (1997a,b) are noteworthy for several reasons. First,
these groups of investigators conducted chronic inhalation toxicity
studies (i.e., chronic bioassays). This is important since miners'
exposures also occur via inhalation, and over a working lifetime.
Secondly, the investigators used an exposure concentration of 2.0 mg/
m\3\ in their bioassays. As noted above, this is the current MSHA
standard for respirable coal mine dust. Thirdly, the exposures involved
nonhuman primates, whose responses are thought to closely mimic those
of man. Some of the key findings of these studies included: deposition
of coal dust in the animals' lungs, retention of coal dust in alveolar
tissue, altered lung defense mechanisms, reduced pulmonary airflows,
and hyperinflation of the lungs. One of the shortcomings of these
studies is that complete dose-response relationships were not
developed. However, at higher exposure concentrations, greater effects
may be expected which is a basic tenet of toxicology. Thus, at exposure
concentrations above 2.0 mg/m\3\, MSHA and NIOSH believe that more
severe obstructive lung disease may occur.
3. Epidemiological Literature
Epidemiology studies have consistently demonstrated the serious
health effects of exposure to high levels of respirable coal mine dust
(i.e., above 2.0 mg/m\3\) over a working lifetime.
Table V-1 lists epidemiology studies since 1986 whose results will
be discussed on the basis of the type of observed health effect.
Studies completed even earlier including the early work of Cochrane
(1962), McLintock, et al. (1971), and Jacobsen, et al. (1971)
demonstrated the adverse health effects (e.g., simple CWP, PMF) of
respirable coal mine dust in British coal miners.
Both early and recent studies have shown that the lung is the major
target organ (i.e., organ in which toxic effects occur) when exposure
to respirable coal mine dust occurs. As seen in Table V-1, numerous
studies of miners have been conducted. Recent U.S. studies were
conducted using data from one or more of the first four rounds of the
National Study of Coal Workers' Pneumoconiosis (NSCWP), and have
provided extensive data on miners' health. Many of these studies
demonstrated that miners are at increased risk of multiple, concurrent
respiratory ailments (Attfield and Seixas, 1995; Kuempel, et al., 1997;
Meijers, et al., 1997; Seixas, et al., 1992).
Table V-1.--Respirable Coal Mine Dust Epidemiological Studies, by
Reported Outcomes From 1986 to Present
------------------------------------------------------------------------
Studies Reported outcomes
------------------------------------------------------------------------
Meijers, et al.,1997................ PMF, CWP, COPD, LLF
Maclaren, et al.,1989............... PMF, CWP, LLF, RS
Kuempel*, et al.,1995............... PMF, CWP, COPD
Bourgkard et al.,1998............... PMF, CWP, LLF
Kuempel*, et al.,1997
Love, et al.,1997
Love, et al.,1992
Attfield and Morring*,1992b......... PMF, CWP
Attfield and Seixas*, 1995
Hodous and Attfield*, 1990
Hurley and Jacobsen, 1986
Hurley and Maclaren, 1987
Hurley, et al., 1987
Starzynski, et al., 1996
Yi and Zhang, 1996
Wang, et al.,1997................... CWP, LLF
Goodwin and Attfield*, 1998......... CWP
Morfeld, et al., 1997
[[Page 42155]]
Marine, et al.,1988................. COPD, LLF, RS
Seixas*, et al., 1993
Soutar and Hurley, 1986
Carta, et al.,1996.................. LLF, RS
Henneberger and Attfield*, 1997
Henneberger and Attfield*, 1996
Seixas*, et al., 1992
Attfield and Hodous*, 1992.......... LLF
Lewis, et al., 1996
------------------------------------------------------------------------
COPD: Chronic obstructive pulmonary disease
CWP: Simple coal workers' pneumoconiosis
LLF: Loss of lung function
PMF: Progressive massive fibrosis
RS: Respiratory symptoms
*: Studies of U.S. Miners Who Participated in the National Study of Coal
Workers' Pneumoconiosis (NSCWP)
a. Simple Coal Workers' Pneumoconiosis (Simple CWP) and Progressive
Massive Fibrosis (PMF). Studies following Cochrane (1962) and McLintock
et al. (1971) have confirmed that the risk of PMF increases with
increasing category of simple CWP (Hurley and Jacobsen, 1986; Hurley,
et al., 1987; Hurley and Maclaren, 1988; Hodous and Attfield, 1990).
However, the risk of PMF was greater than previously predicted among
miners with simple CWP category 1 or without simple CWP (i.e., category
0) (Hurley, et al., 1987). The risk of PMF increased with increasing
cumulative exposure, regardless of the initial category of simple CWP
(Hurley, et al., 1987), indicating that reducing dust exposures is a
more effective means of reducing the risk of PMF than reliance on
detection of simple CWP.
Attfield and Seixas (1995) have demonstrated a relationship between
cumulative exposure to respirable coal mine dust and predicted
prevalence of pneumoconiosis (i.e., simple CWP, PMF). They studied a
group of approximately 3,200 men who worked in underground bituminous
coal mines. The U.S. miners and ex-miners had participated in Round 1
(1970-1972) or Round 2 (1972-1975) of the NSCWP and were examined again
between 1985 and 1988. Chest x-rays were read to determine the number
of cases of simple CWP and PMF. Dust exposure estimates were generated
from measurements of dust concentrations as well as from work history.
A logistic (or logit) regression model was used to estimate prevalence
of simple CWP and PMF. In this statistical analysis, proportions are
transformed to natural logarithmic values, i.e., y = ln [p/(1-p),
before a linear model is fit to the data (Armitage, 1977). The logistic
model assumes that the data have a binomial distribution (e.g.,
presence or absence of PMF) for a given set of covariate values (e.g.,
age, coal rank, dust exposure, pack-years of smoking). Using logistic
modeling, relationships were developed between cumulative dust exposure
and prevalence of simple CWP (category 1+, category 2+) and PMF. These
relationships were the key strengths of the Attfield and Seixas study
and serve as the basis for the Quantitative Risk Assessment of this
rule.
The recent paper of Kuempel, et al. (1997) has provided a detailed
discussion and quantitative presentation of excess risks associated
with respirable coal dust exposures. Their study was based upon results
from previous studies of some 9,000 underground coal miners who
participated in the NSCWP (Attfield and Morring, 1992b; Attfield and
Seixas, 1995). Kuempel, et al. estimated excess (exposure-attributable)
prevalence of simple CWP and PMF (i.e., number of cases of disease
present in a population at a specified time, divided by the number of
persons in the population at that specified time). Point estimates of
excess risk of PMF ranged from 1/1000 to 167/1000 among miners exposed
at the current MSHA standard for respirable coal mine dust. These
estimates were based upon dust exposure that occurred over a miner's
working lifetime (e.g., 8 hours per day, 5 days a week, 50 weeks per
year, over a period of 45 years). Actual occupational lifetime exposure
may be more, due to extended work shifts and work weeks. The point
estimates of PMF presented by Kuempel, et al. (1997) were related to
coal rank, where higher estimates (e.g., 167/1000) were obtained for
high-rank coal (anthracite coal) and somewhat lower estimates were
obtained for medium/low rank bituminous coal (e.g., 21/1000). Within
each coal rank, the estimates of simple CWP cases were at least twice
as high as those for PMF (e.g., 167/1000 PMF vs. 380/1000 simple
CWP<gr-thn-eq>1).
The data of Attfield and Seixas (1995) and Kuempel, et al. (1995;
1997) were consistent with previous data of Attfield and Morring
(1992b) who reported relationships between estimated dust exposure and
predicted prevalence of simple CWP or PMF. They also noted that
exposure-response relationships were steeper for higher ranks of coal
such as anthracite, and concluded that the risks for anthracite miners
appeared to be greater than for miners exposed to lower rank coal dust.
Attfield and Morring (1992b) used similar methods as described above
(i.e., logistic modeling), but included miners from Round 1 of the
NSCWP (1969-1971); thus representing an earlier time point in the NSCWP
when the respirable coal mine dust concentrations were much higher than
they are today.
Recently, Goodwin and Attfield (1998) reported that there were
concerns regarding methodological inconsistencies across surveys given
during the four rounds of the NSCWP. In particular, they noted the
discordance in classification of simple CWP and PMF among readers of
chest films. Despite potential discordance, Goodwin and Attfield (1998)
have confirmed previous findings of a decline in simple CWP prevalence
from 1969 to 1988. Yet, these analyses also demonstrated that simple
CWP has not been eliminated. The Round 4 prevalence rates were 3.9
percent for simple CWP category 1 and higher, and 0.9 percent for
category 2 and higher. This illustrates the need for continued efforts
to reduce dust exposures.
Given the current system for monitoring exposures and identifying
overexposures in the U.S., miners are at
[[Page 42156]]
increased risk of developing simple CWP and PMF from a working lifetime
exposure to respirable coal mine dust (Kuempel, et al. 1997, 1995;
Attfield and Seixas, 1995; Goodwin and Attfield, 1998; Attfield and
Morring, 1992b). Whenever overexposures (i.e., excursions above the
applicable standard) occur, the long-term mean exposure of miners may
be increased, thereby causing an upward shift on the exposure-response
curve. Such a shift then places these overexposed coal miners at
increased risk of developing and dying prematurely from simple CWP and
PMF.
The Attfield and Seixas epidemiological study (1995) is the most
appropriate to use in estimating the benefit of reduction of
overexposures. The authors applied scientific rigor to the collection,
categorization, and analyses of the radiographic evidence for the group
of 3,194 underground bituminous coal miners who participated in Round
4, 1985-1988, of the National Study of Coal Workers' Pneumoconiosis
(NSCWP); this study population excludes 86 miners for whom there was
missing exposure data or unreadable x-rays. Radiologic evidence was
carefully collected and analyzed by multiple independent, NIOSH
certified B readers to identify stages of simple CWP and PMF. In the
targeted population of 5,557 miners, the participating miners (3,280)
were similar to the non-participants (2,277) with regard to age at the
first medical examination and prevalence of simple CWP category 1 or
greater. The non-participants had worked slightly longer, yet had lower
prevalence of simple CWP category 2 or greater, than the participants.
This study describes the differences among current miners and ex-miners
(health-related or job-related) in the relationships between the
estimated cumulative exposure to respirable coal mine dust and
prevalence of simple CWP category 1 or greater. Such data and
relationships were not available in other U.S. studies and non-U.S.
studies.
A potential limitation in the U.S. studies is the possible bias in
the exposure data, which has been the subject of several studies (Boden
and Gold, 1984; Seixas et al., 1991; Attfield and Hearl, 1996). An
advantage of the Attfield and Seixas 1995 study (and the earlier
studies based on the same data set) is that the larger mines included
in these epidemiological studies were shown to have exposure data with
relatively small bias (Attfield and Hearl, 1996). Another limitation in
exposure data used in the U.S. studies is that the airborne dust
concentrations used to estimate individual miners' cumulative exposures
to respirable coal mine dust were based on average concentrations
within job category (these average values were combined with data of
each individual miner's duration employed in a given job). The earlier
U.S. exposure-response studies of miners participating in the first
medical survey of the NSCWP (Attfield and Morring, 1992b; Attfield and
Hodous, 1992; Kuempel, et al., 1995) relied primarily on exposure
measurements from a dust sampling survey during 1968-1969 to estimate
miners' exposures before 1970 (Attfield and Morring, 1992a). An
advantage of the Attfield and Seixas 1995 study is that, in addition to
the pre-1970 exposure estimates, more detailed exposure data were
available to estimate miners' exposures from 1970 to 1987, during which
the mean airborne concentrations were stratified by mine, job, and year
(Seixas, et al., 1991).
The most complete exposure data available are those for coal miners
in the United Kingdom (Hurley, et al., 1987; Hurley and Maclaren, 1987;
Soutar and Hurley, 1986; Marine, et al., 1988; Maclaren, et al., 1989).
These studies include medical examinations and individual estimates of
exposure for more than 50,000 miners for up to 30 years. The U.S.
studies are consistent with these U.K. studies in demonstrating the
risks of developing occupational respiratory diseases from exposure to
respirable coal mine dust. These risks increase with increasing
exposure concentration and duration, and with exposure to dust of
higher ranked coal. The quantitative assessment of risk and associated
benefits were based on the Attfield and Seixas (1995) study because, in
addition to the advantages described above, it best represents the
recent conditions experienced by miners in the U.S. This quantitative
assessment follows in Section VI. The international studies provide an
important basis for comparison with the U.S. findings, and several of
the recent international studies are described in detail here.
Bourgkard, et al. (1998) conducted a 4-year study of a group of
French coal miners who were employed in underground and surface mines.
The investigators examined the prognostic role of cumulative dust
exposure, smoking patterns, respiratory symptoms, lung CT scans, and
lung function indices for chest x-ray worsening and evolution to simple
CWP and PMF. Bourgkard, et al. (1998), through selection of a younger
worker population (i.e., 35-48 years old at start of study), attempted
to focus on the early stages of simple CWP. In essence, they hoped to
identify those miners who needed to be relocated to less dusty
workplaces or who needed to be clinically monitored. Bourgkard, et al.
(1998) concluded that there was an association between cumulative dust
exposure and what was termed chest x-ray ``worsening'' (i.e., increase
in reader-designated category signifying progression of simple CWP).
Their conclusion, however, was based on pooling of the data (i.e.,
three combined groups of miners) who had different cumulative exposures
(i.e., 20, 66 and 85 mg-yr/m\3\).
Love, et al. (1997, 1992) reported on occupational exposures and
the health of British opencast (i.e., surface or strip) coal miners.
They studied a group of approximately 1,200 miners who were employed at
sites in England, Scotland, and Wales. The mean age of the men was 41;
many had worked in the mining industry since the 1970s. To determine
dust exposure levels, full shift personal samples were collected. Most
were respirable dust samples which were collected using Casella
cyclones according to the procedures described by the British Health
and Safety Executive (HSE). Thus exposure determinations would be
comparable to exposure determinations obtained in U.S. surface coal
mines since both measure respirable dust according to the BMRC
criteria.
These investigators found a doubling in the relative risk of
developing profusion of simple CWP category 0/1 for every 10 years of
work in the dustiest jobs in surface mines. These respirable coal dust
exposures were under 1 mg/m\3\. Love, et al. (1992, 1997), like other
investigators, emphasized the need for monitoring and controlling
exposures to respirable coal mine dust, particularly in high risk
operations (e.g., drillers, drivers of bulldozers).
Meijers, et al. (1997) studied Dutch coal miners who were examined
between 1952 and 1963, and who were followed until the end of 1991.
They reported an increased risk of mortality from simple CWP and PMF
among miners who had generally worked underground for 20 or more years.
Their conclusions were based upon dramatic increases in standardized
mortality ratios (SMRs). There were several limitations in this study,
however.
Morfeld, et al. (1997) published a recent paper that investigated
the risk of developing simple CWP in German miners and addressed the
occupational exposure limit for respirable coal dust in Germany. Their
study included approximately 5,800 miners who worked underground from
the late
[[Page 42157]]
1970s to mid-1980s. Morfeld, et al. observed increases in relative
risks (RRs) of developing early x-ray changes, category 0/1, that were
exposure-dependent. Relative risks (RRs) increased with higher dust
concentrations.
Starzynski, et al. (1996) conducted a mortality study on a group of
11,224 Polish males diagnosed with silicosis, simple CWP, or PMF
between 1970 and 1985. This cohort was subdivided by occupation into
four subcohorts: coal miners (63%); employees of underground work
enterprises (8%) (i.e., drift cutting and shaft construction jobs);
metallurgical industry and iron, and nonferrous foundry workers (16%);
and refractory materials, china, ceramics and quarry workers. The
investigators found that coal miners had a slight, statistically
significant excess overall mortality (i.e., all causes) as indicated by
a Standardized Mortality Ratio (SMR) of 105 (with a 95% Confidence
Interval (C.I.) of 100-110). Also, excess of deaths from diseases of
the respiratory system among coal miners was nearly four times that of
the referent population (SMR of 383 with a 95% C.I. of 345-424). The
study of Starzynski, et al. (1996) agrees with others that there is
premature mortality among coal miners from simple CWP and PMF.
Unfortunately, there is little or no information presented on miner
work history, exposure assessment (e.g., respirable coal mine dust,
silica), and mine environment (e.g., coal rank(s), underground vs.
surface mining).
Yi and Zhang (1996) conducted a study to measure the progression
from simple CWP to PMF or death among a cohort of 2,738 miners with
simple CWP who were employed at the Huai-Bei coal mine in China.
Relative risks (i.e., RRs) were calculated for progression from simple
CWP category 1 to simple CWP category 3 and for progression from simple
CWP category 3 to death. Their results demonstrated that miners with
simple CWP category 1 are at risk of developing simple CWP category 2
and simple CWP category 3 (e.g., RRs of 1.101 and 2.360, respectively).
They also found that miners with PMF had a decreased life expectancy.
Other risk factors for development of PMF included long-term work
underground, and drilling. This study was limited by a lack of exposure
assessment, estimation of miner smoking histories, and use of a
radiological classification system that differs from that of the ILO.
Hurley and Maclaren (1987) studied British coal miners who were
examined between 1953 and 1978, over 5-year intervals. They have shown
that exposure to respirable coal dust increases the risks of developing
simple CWP and of progressing to PMF. As seen in their data analysis,
these responses were dependent upon dust concentration and coal rank.
That is, greater responses were seen at higher dust concentrations and
with higher rank coal (i.e., increasing per cent carbon. The
investigators also noted that estimated risks were unaffected by
changes in the proportion of miners with simple CWP who transferred
jobs. The authors concluded that ``limiting exposure to respirable coal
dust is the only reliable way of limiting the risks of radiological
changes to miners.''
b. Other Health Effects. As noted in Table V-1, there were 16
studies in which the loss of lung function (LLF) was examined in coal
miners. Six of these studies also included an evaluation of respiratory
symptoms (RS) in the miners. There were five studies describing chronic
obstructive pulmonary disease (COPD) in miners.
Henneberger and Attfield (1997; 1996), Kuempel, et al. (1997),
Seixas, et al. (1993), Attfield and Hodous (1992), and Seixas, et al.
(1992) evaluated data from pulmonary function tests and standardized
questionnaires to miners in the NSCWP. A common finding in their
studies was an increase in respiratory symptoms such as cough,
shortness of breath, and wheezing. The symptoms were dependent upon the
dust concentration to which the miners had been exposed, with more
pronounced symptoms occurring after long-term exposures to higher
exposure levels. These studies also demonstrated that a loss of lung
function occurred among miners.
Attfield and Hodous (1992) studied U.S. miners who had spent 18
years underground (on average) and who participated in Round 1 (1969-
1971) of the NSCWP. They observed that greater reductions in pulmonary
function were associated with exposure to higher ranks of coal (i.e.,
anthracite vs. bituminous vs. lignite). Using linear regression models,
Kuempel et al., (1997) predicted the excess (exposure attributable)
prevalence of lung function decrements among miners with cumulative
exposures to respirable coal mine dust of 2 mg/m\3\ for 45 years (i.e.,
90 mg-yr/m\3\). The excess prevalence estimated were 315 and 139 cases
per thousand for forced expiratory volume in one second
(FEV<INF>1</INF>) of 80% and 65% of predicted normal values,
respectively, among never-smoking miners (a sub-group of 977 NSCWP
participants studied in Seixas et al., 1993). Such reductions in
(FEV<INF>1</INF> are clinically significant; (FEV<INF>1</INF> 80% (of
predicted normal values) is a measure that is used to determine
ventilatory defects (American Thoracic Society, 1991). Three recent
studies found impaired (FEV<INF>1</INF> to be a predictor of increased
pre-mature mortality (Weiss, et al., 1995; Meijers, et al., 1997;
Hansen et al., 1999).
Seixas, et al. (1993) conducted an analyses of 977 underground coal
miners who began working in or after 1970 and were participants of both
NSCWP Round 2 (1972-1975) and Round 4 (1985-1988). They found a rapid
loss of lung function in miners and further declines in lung function
with continuing exposure to coal mine dust. Collectively these studies
have shown that the prevalence of decreased lung function was
proportional to cumulative exposure. That is, with exposure to higher
coal dust levels over a working lifetime, there were more miners who
experienced a loss of lung function. Also, the types of respiratory
symptoms and patterns of pulmonary function decrements observed by both
Attfield and Hodous (1992) Seixas, et al. (1992;1993) are
characteristic of COPD.
The U.S. findings on respiratory symptoms and loss of lung function
in miners have agreed with those of previous British studies by Marine,
et al. (1988) and Soutar and Hurley (1986). Marine, et al. (1988)
analyzed data from British coal miners and focused their attention on
respiratory conditions other than simple CWP and PMF. In particular,
they examined the Forced Expiratory Volume in one second
(FEV<INF>1</INF>) among smoking and nonsmoking miners and, on the basis
of reported respiratory symptoms, identified those miners with
bronchitis. Using these data, logistic regression models were used to
estimate the prevalence of chronic bronchitis and loss of lung
function. Marine, et al. concluded that both exposure to respirable
coal mine dust and smoking independently cause decrements in lung
function; their contributions to COPD appeared to be additive in coal
miners.
Soutar and Hurley (1986) examined the relationship between dust
exposure and lung function in British coal miners and ex-miners. The
men who were studied were employed in coal mines in the 1950s and were
followed up and examined 22 years later. These miners and ex-miners
were categorized as smokers, ex-smokers, or nonsmokers. The Forced
Expiratory Volume in one second (FEV<INF>1</INF>), the Forced Vital
Capacity (FVC), and the (FEV<INF>1</INF>/FVC) ratios decreased in all
study groups and these reductions in lung function were inversely
proportional to dust exposure. Thus, Soutar and Hurley concluded that
exposure to respirable coal mine dust can cause severe respiratory
[[Page 42158]]
impairment, even without the presence of simple CWP or PMF. They
speculated that the pathology of coal dust-induced lung disease differs
from that induced by smoking.
Recent studies from China (Wang, et al., 1997) and the European
community (Bourgkard, et al., 1998; Carta, et al., 1996; Lewis, S., et
al., 1996) have also supported the British and U.S. findings which
demonstrated the correlation between occupational exposure to coal dust
and respiratory symptoms and loss of lung function in miners.
Wang, et al. (1997) examined lung function in underground coal
miners and other workers from several other factories in Chongqing,
China. For their study, information was obtained on exposure duration,
results of radiographic tests, and smoking history. Pulmonary function
tests were performed, providing the Forced Expiratory Volume in one
second (FEV<INF>1</INF>), the Forced Vital Capacity (FVC), and
(FEV<INF>1</INF>/FVC) data. Additionally, the diffusing capacity for
carbon monoxide (DL<INF>CO</INF>) was measured. This is an indicator of
diffusion impairment at the ``blood-gas barrier'' which may occur, for
example, when this barrier becomes thickened (West, 1990; 1992). Wang,
et al. (1997) found that there was impairment of pulmonary function
among the coal miners and they had evidence of obstructive disease.
Like other studies, such effects were observed among coal miners even
in the absence of simple CWP. Pulmonary function was further decreased
when simple CWP was present. This study did not provide exposure
measurements and there was no consideration of exposure-response
relationships. Also, silica exposures and their potential effects were
not examined in the underground coal miners.
As noted above, Bourgkard, et al. (1998) was interested in the
earlier stages of simple CWP (i.e., Categories 0/1 and 1/0) and the
prognostic role of cumulative dust exposure, smoking patterns,
respiratory symptoms, lung CT scans, and lung function indices for
chest x-ray worsening and evolution to simple CWP category 1/1 or
higher. Over a 4-year period, they studied French coal miners who were
employed in underground and surface mines. Bourgkard, et al. (1998)
found that, at the first medical examination, the ratio of the Forced
Expiratory Volume in one second (FEV<INF>1</INF>) to the Forced Vital
Capacity (FVC) (i.e., (FEV<INF>1</INF>/FVC) and other airflows
determined from a forced expiration (West, 1990; 1992) were lower among
miners who later developed simple CWP category 1/1 or higher. These
miners also experienced more wheezing at the first medical examination.
Thus, the results of their study suggested that lung function changes
may serve as an early indicator of miners who are at increased risk of
developing simple CWP and PMF and who should be monitored more closely.
Carta, et al. (1996) have examined the role of dust exposure on the
prevalence of respiratory symptoms and loss of lung function in a group
of young Italian coal miners (i.e., mean age at hire 28.9 years, mean
age at first survey 31.2 years). These miners worked underground and
were exposed to lignite (i.e., low rank coal) which had a 5-7% sulfur
content. They were followed for a period of 11 years, from 1983 and
1993. Carta, et al. (1996) found few abnormalities on miner chest x-
rays taken throughout the 11-year study. However, there was an
increased prevalence of respiratory symptoms and loss of lung function.
This was particularly noteworthy since dust exposures were often below
1.0 mg/m\3\; the cumulative dust exposure for the whole cohort was 6.7
mg-yr/m\3\ after the first survey. Thus, Carta, et al. (1996)
demonstrated that miners experience respiratory effects of exposure to
dust generated from a lower rank coal and at lower concentrations. They
have recommended yearly measurements of lung function for miners.
Lewis, et al. (1996) studied a group of British miners, many of
whom entered the coal industry in the 1970s. Based upon chest x-rays,
the miners had no evidence of simple CWP or PMF. The objective of this
study was to determine whether coal mining (i.e., exposure to
respirable coal mine dust) is an independent risk factor for impairment
of lung function. Lewis, et al. (1996) found that there was a loss of
lung function in miners (smokers and nonsmokers), particularly among
miners who were under approximately 55 years of age. For miners who
smoked, there was a greater loss of lung function than in nonsmoking
miners with the same level of exposure to respirable coal mine dust.
Above age 55, the loss of lung function was similar for miners and
their controls, although all smokers continued to exhibit a greater
loss of lung function than nonsmokers. Lewis, et al. (1996) concluded
that the deficits in lung function may occur in the absence of simple
CWP and PMF, and independent from the effects of smoking.
There have been two recent mortality studies that have demonstrated
a relationship between exposure to respirable coal mine dust and
development of COPD. This association was reported by Kuempel, et al.
(1995) in the U.S., and by Meijers, et al. (1997) in the Netherlands.
These two groups of investigators have reported that occupationally-
induced COPD (e.g., chronic bronchitis, emphysema) can occur in miners,
with or without the presence of simple CWP or PMF. They also found that
the risk of premature mortality from COPD was elevated among miners and
could be separated from the effects of smoking and age.
Kuempel, et al. (1995) found an increase in relative risk (RR) of
premature mortality from COPD among U.S. coal miners who participated
in the NSCWP from 1969 through 1971. In their data analysis, the
exposure-response relationship was evaluated using the Cox proportional
hazards model. This model assumes that the hazard ratio between
nonexposed and exposed groups does not significantly change with time.
When fitting a curve to the data (e.g., log-linear), cumulative
exposure was expressed as a categorical or continuous variable. Due to
model limitations (e.g., less statistical power, influence of category
scheme, use of lowest exposure group for comparisons vs. use of non-
exposed group), Kuempel, et al. (1995) believed that the exposure data
should be expressed as a continuous variable. If, for example, the
cumulative exposure was 90 mg-yr/m\3\ (i.e., 2 mg/m\3\ for 45 years),
then the relative risk of mortality from chronic bronchitis or
emphysema was 7.67. Kuempel, et al. (1995) also showed that relative
risk decreased with lower cumulative exposures (i.e., below 90 mg-yr/
m\3\) and increased with higher cumulative exposures (i.e., above 90
mg-yr/m\3\). Thus, these investigators demonstrated a statistically
significant exposure-response relationship for COPD.
Meijers, et al. (1997) have shown, among Dutch miners, reductions
in lung volumes and capacities are good predictors of the increased
risk of premature mortality from COPD. For example, a diminished forced
expiratory volume in one second (FEV<INF>1</INF>) or a diminished ratio
of the FEV<INF>1</INF> to the forced vital capacity \10\ (FVC) (i.e.,
FEV<INF>1</INF>/FVC) upon medical examination was associated with a
significantly increased standardized mortality ratio (SMR) for COPD
(322 and 212, respectively). In other words, miners with diminished
lung capacity based on FEV<INF>1</INF> were two to three times more
likely to die prematurely due to COPD than miners who had normal lung
function. In contrast, SMRs for COPD were not
[[Page 42159]]
significantly increased in miners with normal lung volumes and
capacities. These data support prior conclusions of Seixas, et al.
(1992, 1993) and Attfield and Hodous (1992) based on morbidity studies.
---------------------------------------------------------------------------
\10\ Forced vital capacity (FVC) is the total volume of gas that
can be exhaled with a forced expiration after a full inspiration;
The vital capacity measured with a FVC may be less than that
measured with a slower exhalation (West, 1992).
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VI. Quantitative Risk Assessment
As mentioned previously, in addition to this proposed notice of
rulemaking, today's Federal Register contains another NPRM,
Determination of Concentration of Respirable Coal Mine Dust, RIN 1219-
AB18. In combination, these rules present MSHA's strengthened plan to
meet the Mine Act's requirement that a miner's exposure to respirable
coal mine dust be at or below the applicable standard on each and every
shift. MSHA's improved program to eliminate overexposures on each and
every shift includes the simultaneous implementation of an improved
tool to identify overexposures (i.e., inspectors use of single, full-
shift samples for noncompliance determinations) and this proposed
regulation, requiring operators to verify ventilation plans in
underground coal mines.
Having reviewed the reported health effects associated with
exposure to coal mine dust, we have evaluated the evidence to determine
whether the current regulatory strategy can be improved. The criteria
for this evaluation is established by the Mine Act under section
101(a)(6)(A) [30 U.S.C. 811(a)(6)(A)] which provides that:
The Secretary, in promulgating mandatory standards dealing with
toxic materials or harmful physical agents under this subsection,
shall set standards which most adequately assure on the basis of the
best available evidence that no miner will suffer material
impairment of health or functional capacity even if such miner has
regular exposure to the hazards dealt with by such standard for the
period of his working life.
Based on Court interpretations of similar language under the
Occupational Safety and Health Act, there are three questions that must
be addressed: (1) Whether health effects associated with the current
pattern of overexposures on individual shifts constitute a material
impairment to miner health or functional capacity; (2) whether the
current pattern of overexposures on individual shifts places miners at
a significant risk of incurring any of these material impairments; and
(3) whether the proposed rules would substantially reduce those risks.
The criteria for evaluating the health effects evidence do not
require scientific certainty. The need to evaluate risk does not mean
that an agency is placed into a ``mathematical straightjacket.'' See
Industrial Union Department, AFL-CIO v. American Petroleum Institute,
448 U.S. 607, 100 S.Ct 2844 (1980), otherwise known as the ``Benzene''
decision. When regulating on the edge of scientific knowledge,
certainty may not be possible and,
so long as they are supported by a body of reputable scientific
thought, the Agency is free to use conservative assumptions in
interpreting the data * * * risking error on the side of
overprotection rather than underprotection (Id at 656).
The statutory criteria for evaluating the health evidence do not
require MSHA and NIOSH to wait for absolute certainty and precision.
MSHA and NIOSH are required to use the ``best available evidence''
(section 101(a)(6)(A) of the Mine Act (30 U.S.C. 811(a)(6)(A)).
As explained earlier, MSHA's objective in strengthening the
requirements for verifying the effectiveness of dust control plans, and
in enforcing effective plans through the new enforcement policy
proposed in this notice, is to ensure that no miner is exposed to an
excessive concentration (i.e., a concentration in excess of the
applicable standard) of respirable dust on any individual shift. Annual
inspector samples have demonstrated overexposures on individual shifts
in many mines. Data compiled from the far more frequent, bimonthly,
operator sampling program show that in many mines, the applicable dust
standard is exceeded on a substantial percentage of the production
shifts. This pattern has persisted for many years, and, since
individual shift excursions above the applicable standard are permitted
under the existing program, the same pattern can be expected to
continue over the working lifetime of affected miners--unless an effort
is made to eliminate excess exposures on individual shifts. In this
quantitative risk assessment (QRA), MSHA will demonstrate that reducing
coal mine dust concentrations, over a 45-year occupational lifetime, to
no more than the applicable standard on just that percentage of shifts
showing an excess, thereby lowering the cumulative exposure to
respirable coal mine dust than would otherwise occur, would
significantly reduce the risk of both simple CWP and PMF among miners.
We have estimated the health benefits of the two rules arising from the
elimination of overexposures on all shifts at only those MMUs
exhibiting a pattern of recurrent overexposures on individual
shifts.\11\
---------------------------------------------------------------------------
\11\ By ``exhibiting a pattern of recurrent overexposures,''
MSHA means that, at a 95-percent confidence level, the applicable
standard is exceeded on at least [six] shifts per year. Using a
different definition of ``recurrent pattern of overexposures'' in
these analyses would change the estimate of the reduction in risk
and associated benefits. For example, if the definition were that
four or more DO bimonthly exposure measurements exceeded the
applicable standard, we could state, with 95% confidence, that the
standard was exceeded on at least 20 shifts in a year of 384 shifts.
This would reduce the population for whom we are estimating
benefits, and decrease the estimated number of prevented cases by
19%.
---------------------------------------------------------------------------
Based on 1999 operator data, there were 704 MMUs (out of 1,251
total) at which dust concentrations for the designated occupation (DO)
exceeded the applicable standard on at least two of the sampling shifts
(MSHA, Datafile:Operator.ZIP).\12, 13\ MSHA considers these 704 MMUs,
representing more than one-half of all underground coal miners working
in production areas, to have exhibited a pattern of recurrent
overexposures. Valid operator DO samples were collected on a total of
18,569 shifts at these 704 MMUs, and the applicable standard was
exceeded on 3,977 of these shifts, or 21.4 percent. For this 21.4
percent, the mean excess above the standard, as measured for the DO
only, was 1.04 mg/m\3\.
---------------------------------------------------------------------------
\12, 13\ MSHA estimates an MMU average of 384 production shifts
per year. Since mine operators are required to submit five valid
designated operator (DO) samples to MSHA every two months, there
would typically be 30 valid DO samples--representing 30 of the 384
production shifts--for each MMU that was in operation for the full
year. If dust concentrations on two or more of the sampled shifts
exceeded the standard, then it follows, at a 95-percent confidence
level, that the standard was exceeded on at least [six] shifts over
the full year.
---------------------------------------------------------------------------
These results are based on a large number of shifts (an average of
approximately 26 at each of the 704 MMUs). Therefore, assuming
representative operating conditions on these shifts, the results can be
extrapolated to all production shifts, including those that were not
sampled, at these same 704 MMUs. With 99-percent confidence, the
overall percentage of production shifts on which the DO sample exceeded
the standard was between 20.6 percent and 22.2 percent for 1999. At the
same confidence level, again assuming representative operating
conditions, the overall mean excess on noncompliant shifts at these
MMUs was between 0.96 mg/m\3\ and 1.12 mg/m\3\. If operators tend to
reduce production and/or increase dust controls on sampled shifts (as
some commenters to the previous single, full-shift sample rulemaking
and the Dust Advisory Committee have alleged) then the true values
could be
[[Page 42160]]
higher than the upper endpoints of these 99-percent confidence
intervals.
In 1998, MSHA attempted to enforce compliance on individual shifts.
Therefore, to compare the 1999 pattern of excess exposures on
individual shifts to that of previous years under the current
enforcement policy, MSHA examined the regular bimonthly DO sample data
submitted to MSHA by mine operators in the eight years from 1990
through 1997. The same three parameters were considered as discussed
above for 1997: (1) The percentage of MMUs exhibiting a pattern of
recurrent overexposures, as indicated by at least two of the valid
measurements above the applicable standard in a given year; (2) for
those and only those MMUs exhibiting recurrent overexposures, the
overall percentage of production shifts on which the DO was
overexposed, as estimated by the percentage of valid measurements above
the applicable standard; and (3) for the MMUs identified as exhibiting
recurrent overexposures, the mean excess above the applicable standard,
as calculated for just those valid measurements that exceeded the
applicable standard in a given year.
Although MSHA found minor differences between individual years,
there was no statistically significant upward or downward trend in any
of these three parameters over the 1990-1997 time period (see Table VI-
1). In 1999, however, there was a significant decrease in the average
excess above the applicable standard (Parameter #3) for MMUs exhibiting
recurrent overexposures. MSHA attributes this decrease to two important
changes in the Agency's inspection program, beginning near the end of
1998. These changes, which both resulted in increased inspector
presence, were: (1) An increase in the frequency of MSHA dust sampling
at underground coal mines; and (2) initiation of monthly spot
inspections at mines that were experiencing difficulty in maintaining
consistent compliance with the applicable dust standard.
Table VI-1.--1990-1997, Distribution of Parameters of Annual Overexposure to Respirable Coal Mine Dust
----------------------------------------------------------------------------------------------------------------
Parameter #1 Parameter #2 Parameter #3
1990-1997 (percent) (percent) (mg/m\3\)
----------------------------------------------------------------------------------------------------------------
Number of Years................................................. 8 8 8
Median.......................................................... 52.6 20.5 1.23
Mean (Standard Error)........................................... 50.9 20.6 1.25
(1.62) (0.32) (0.020)
----------------------------------------------------------------------------------------------------------------
Parameter #1: Percentage of MMUs exhibiting a pattern of recurrent overexposures.
Parameter #2: For those MMUs exhibiting a pattern of recurrent overexposures, the percentage of production
shifts on which the DO was overexposed.
Parameter #3: For those MMUs exhibiting a pattern of recurrent overexposures, the mean excess above the
applicable standard among valid DO measurements that exceeded the applicable standard.
MSHA invites public comment on whether these three parameters,
based on operators' 1999 samples, under-represent or over-represent the
frequency and/or magnitude of excessive dust concentrations on all
individual shifts--including those that are not sampled. These data
suggest that, unless changes are made to enforce the dust standard on
every shift, the same average pattern of overexposures observed in 1999
will persist into the future. Therefore, we conclude that without the
proposed changes:
<bullet> Approximately 56 percent of all MMUs would continue to
have a pattern of recurrent overexposures on individual shifts;
<bullet> At those MMUs with recurrent overexposures, full shift
average respirable dust concentrations for the DO would continue to
exceed the applicable standards on about 21 percent of all production
shifts;
<bullet> Among those shifts on which DO exposure exceeds the
applicable standards, the mean excess for the DO would continue to be
approximately 1.0 mg/m\3\.
If all overexposures on individual shifts are eliminated, the
reduction in total respirable coal mine dust inhaled by a miner over a
working lifetime will depend on the following factors: the average
volume of air inhaled on each shift that would otherwise have exceeded
the applicable standard, the degree of reduction in respirable dust
concentration in the air inhaled on such shifts, and the number of such
shifts per working lifetime. If a miner inhales ten cubic meters of air
on a shift (U.S. EPA, 1980), reducing the respirable dust concentration
in that air by 1.0 mg/m\3\ would result in 10 mg less dust inhaled on
that shift alone. Assuming the miner works 240 shifts per year, then
reducing inhaled respirable dust by an average of 10 mg on 21 percent
of the shifts would reduce the total dust inhaled by 504 mg per year,
or nearly 22,700 mg over a 45-year working lifetime:
1.0 mg per m\3\ of inhaled air
x 10 m\3\ inhaled air per shift
x 50.4 affected shifts (i.e., 21% of 240) per work year
x 45 work years per working lifetime
= 22,680 mg less dust inhaled per working lifetime.
The Secretaries invite comments on the health benefits expected
from reducing the total coal mine dust inhaled over a working lifetime
by this amount.
In Section V, the strengths and weaknesses of various
epidemiological studies were presented, supporting the selection of
Attfield and Seixas (1995) as the study that provides the best
available estimate of material health impairment with respect to CWP
and PMF. Two of the distinguishing qualities of this study are the
dose-response relationship over a miners' lifetime and the fact that
these data best represent the recent conditions experienced by miners
in the U.S. Using this relationship it is possible to evaluate the
impact on risk of both simple CWP and PMF expected from bringing dust
concentrations down to or below the applicable standard on every shift.
This is the only contemporary epidemiological study of CWP and PMF
providing such a relationship.
Attfield and Seixas used two or three B readers to identify the
profusion of opacities using the ILO classification scheme. If three
readings were available, the median value was used. If two readings
were available, the higher of the two ILO categories was recorded.
Eighty radiographs were eliminated because only one reading was
available. The most inclusive category of CWP 1<SUP>+</SUP> includes
simple CWP, categories 1, 2, 3, as well as PMF. Category CWP
2<SUP>+</SUP> does not include simple CWP, category 1, but does include
the more severe simple
[[Page 42161]]
CWP categories, 2 and 3, as well as PMF. The third category used in
their report was PMF, denoting any category of large opacities.
Attfield and Seixas (1995) provided logistic regression models for
the prevalence for CWP 1<SUP>+</SUP>, CWP 2<SUP>+</SUP> and PMF as a
function of cumulative dust exposure, expressed as the product of dust
concentration measured in the mine atmosphere and duration of exposure
at that concentration. These models can be used to estimate the impact
on miners' risk of both simple CWP and PMF of reducing lifetime
accumulated exposure by eliminating excessive exposures on a given
percentage of individual shifts.
At the MMUs being considered (those exhibiting a pattern of
recurrent overexposures), bringing dust concentrations down to no more
than the applicable standard on each and every production shift would
reduce DO exposures on the affected shifts by an average of 1.04 mg/
m\3\. Assuming this average reduction applies to only 21 percent of the
shifts, the effect would be to reduce cumulative exposure, for each
miner exposed at or above the DO level, by 0.22 mg-yr/m\3\ over the
course of a working year (i.e., 21 percent of shifts in one year, times
1.04 mg/m\3\ per shift). Therefore, over a 45-year working lifetime,
the benefit to each affected miner would, on average, amount to a
reduction in accumulated exposure of approximately 10 mg-yr/m\3\ (i.e.,
45 years times 0.22 mg-yr/m\3\ per year). If, as some miners have
testified, operator dust samples submitted to MSHA tend to under-
represent either the frequency or magnitude (or both) of individual
full shift excursions above the applicable standard, then eliminating
such excursions would provide a lifetime reduction of even more than 10
mg-yr/m\3\ for each exposed miner.
The Attfield and Seixas models predict the prevalence of CWP
1<SUP>+</SUP>, CWP 2<SUP>+</SUP>, and PMF for miners who have
accumulated a given amount of exposure, expressed in units of mg-yr/
m\3\, by the time they attain a specified age. Benefits of reducing
cumulative exposure can be estimated by calculating the difference
between predictions with and without the reduction. For example,
suppose a miner begins work at age 20 and retires at age 65. By the
year of retirement, that miner is expected to accumulate nearly 10 mg-
yr/m\3\ less exposure if individual shift excursions are eliminated.
For 65-year-old miners, reducing accumulated dust exposure by a total
of 10 mg-yr/m\3\ reduces the predicted prevalence of CWP 1<SUP>+</SUP>
by at least 11 per thousand (See Table VI-2).
This 11 per thousand, however, applies only to miners of age 65.
The Attfield and Seixas models provide different predictions for each
year of age that a miner attains. The predicted benefit turns out to be
smaller for younger miners and larger for older miners. This is partly
because younger miners will have accumulated less exposure reduction
from the proposed changes, and partly because the Attfield and Seixas
models depend directly on age as well as on cumulative exposure. The
health effects of recurrent overexposures can occur long after the
overexposures occurred. Even after a miner retires and is no longer
exposed to respirable coal mine dust, the extra risk attributable to an
extra 10 mg-year/m\3\, accumulated earlier, continues to increase with
age. Consequently, the benefit to be gained from eliminating individual
shift excursions also continues to increase after a miner is no longer
exposed. For example, assuming no additional exposure after age 65, the
predicted reduction in average prevalence of CWP1<SUP>+</SUP> increases
from 12 per thousand at age 65 to 17 per thousand at age 70.
Presumably, the increasingly greater predicted reduced risk of disease
after age 65 is due to the latent effects of the reduction in earlier
exposure.
To project the benefits of the two rules expected from eliminating
overexposures on individual shifts, MSHA applied the Attfield and
Seixas models to a hypothetical population of miners who, on average,
begin working at age 20 and retire at age 65, assuming different
lifetimes. The risks for three different ages have been presented to
show a range of risk depending on the lifetime: 65, 73, and 80 years.
During the 45 ``working years'' between 20 and 65, the lifetime benefit
accumulates at a rate of 0.22 mg-yr/m\3\ of reduced exposure per year,
reaching a maximum of about 10 mg-yr/m\3\ at age 65. Between ages 65
and 80, the accumulated reduction in dust exposure remains at an
estimated average of 10 mg-yr/m\3\, but the benefit in terms of both
simple CWP and PMF risk continues to increase, as explained previously.
The expected lifetime for all American males conditional on their
having reached 20 years of age, is 73 years (calculated from: U.S.
Census March 1997, Table 18; U.S. Census March 1997, Table 119).\14\ On
average, the best estimate of the lifetime benefit to exposed miners is
expressed by the reduction in prevalence of disease at age 73. Carrying
out the calculation at a 73-year average lifetime, MSHA expects that,
at the MMUs under consideration, bringing dust concentrations down to
no more than the applicable standard on each shift will:
---------------------------------------------------------------------------
\14\ Since females have a greater life expantancy than males,
expected benefits would increase if the production of female miners
were to increase substantially in the future.
---------------------------------------------------------------------------
<bullet> Reduce the combined risk of simple CWP and PMF by at least
18 cases per 1000 affected DO miners; \15\
---------------------------------------------------------------------------
\15\ ``affected DO miners'' include all miners who work at the
56-percent of MMUs under consideration and who are exposed to dust
concentrations similar to the DO over a 45-year working lifetime.
---------------------------------------------------------------------------
<bullet> Reduce the combined risk of simple CWP (category 2 and 3)
and PMF by at least 9.8 cases per 1000 affected DO miners;
<bullet> Reduce the risk of PMF by at least 5.1 cases per 1000
affected DO miners.
Presented in the first row of Table VI-2 are the average reductions
in risk for simple CWP and PMF combined, and PMF alone, over an
occupational lifetime, among affected DO miners who live to ages 65,
73, and 80, who have worked at an MMU exhibiting a pattern of recurrent
overexposures. Across health outcomes, the benefit due to the predicted
reduction in cumulative exposure to respirable coal mine dust, through
limiting miners' exposure to no more than the applicable standard on
each and every shift, increases with age.
When the dust concentration measured for the DO exceeds the
applicable standard, measurements for at least some of the other miners
may also exceed the standard on the same shift, though usually by a
lesser amount. Furthermore, although the DO represents the occupation
most likely to receive the highest exposure, other miners working in
the same MMU may be exposed to even higher concentrations than the DO
on some shifts. Therefore, in addition to the affected DO miners, there
is a population of other affected miners who are also expected to
experience a significant reduction in risk as a result of eliminating
overexposures on their individual shifts.
To estimate how many miners other than the DO would be
substantially affected, MSHA examined the results from all valid dust
samples collected by MSHA inspectors in underground MMUs during 1999
(MSHA, Data file: Inspctor.zip). Within each MMU, the inspector
typically takes one full-shift sample on the DO and, on the same shift,
four or more additional samples representing other occupations. On 896
shifts, at a total of 450 distinct MMUs, the DO measurement exceeded
the applicable standard and there were at least four valid measurements
for other
[[Page 42162]]
occupations available for comparison. There was an average of 1.2 non-
DO measurements in excess of the standard on shifts for which the DO
measurement exceeded the standard.\16\ For non-DO measurements that
exceeded the standard on the same shift as a DO measurement, the mean
excess above the standard was approximately 0.8 mg/m\3\.\17\
---------------------------------------------------------------------------
\16\ With 95-percent confidence, on shifts for which the DO
measurement exceeds the standard, the mean number of other
occupational measurements also exceeding the standard is at least
1.11.
\17\ With 95-percent confidence, the mean excess is at least
0.72 mg/m\3\.
---------------------------------------------------------------------------
Combining these results with the 21-percent rate of excessive
exposures observed for the DO on individual shifts, it is reasonable to
infer that, at the MMUs under consideration, an average of 1.2 other
miners, in addition to the one classified as DO, is overexposed on at
least 21 percent of all production shifts. Over the course of a working
year, the reduction in exposure expected for these other miners is 0.17
mg-yr/m\3\ (i.e., 21 percent of one year, times 0.8 mg/m\3\).
To assess the reduction in risk expected from eliminating all
single-shift exposures for faceworkers experiencing lower exposures
than the DO, MSHA again applied the Attfield and Seixas models to
miners who begin working at age 20, retire at age 65, assuming various
lifetimes: 65, 73, and 80 years. This time, however, the resulting
decrease in predicted prevalence was multiplied by 1.2/7=0.171, to
reflect the fact that the assumed rate of overexposure applies, on
average, to about 17 percent of the faceworkers not classified as the
DO.\18\
---------------------------------------------------------------------------
\18\ There are an estimated 7 non-DO miners for each DO miner,
and an average of 1.2 of these 7 miners are overexposed.
---------------------------------------------------------------------------
In the second row of Table VI-2, we see that over an occupational
lifetime, the beneficial average reduction in risk for simple CWP and
PMF combined, and for PMF alone, increases with age. However, the
magnitude of the risk reduction is smaller for the affected non-DOs
than the affected DOs. This is expected because the estimated
probability that a non-DO will be overexposed on a given shift is only
17 percent of the corresponding probability for the DO. Based on this
calculation for the MMUs under consideration, the predicted reduction
in risk for faceworkers other than the DO who live an expected lifetime
of 73 years is at least: 2.3 fewer cases of PMF or simple CWP per
thousand affected miners; 1.3 fewer cases of PMF or simple CWP,
categories 2 or 3, per thousand affected miners; and 0.7 fewer cases of
PMF per thousand affected miners.
Various data, assumptions and caveats were used to conduct the
quantitative risk assessment and benefits analyses. Therefore, we
request any information which would enable us to conduct more accurate
analyses of the estimated health benefits of the single, full-shift
sample rule and plan verification rule, both individually and in
combination.
Table VI-2.--By Age, Average Reduction in Risk of Occupational Respiratory Disease per 1,000 Affected
Underground Coal Miners Expected To Result From Implementation of Single, Full-Shift Sample and Plan
Verification
----------------------------------------------------------------------------------------------------------------
Reduction in risk of occupational respiratory disease per 1,000 affected miners
--------------------------------------------------------------------------------
Simple CWP,\a\ Simple CWP (categories 2 PMF
(categories 1, 2 or 3) or or 3) or PMF --------------------------
Type of miner PMF \b\ --------------------------- Age
--------------------------- Age --------------------------
Age ---------------------------
--------------------------- 65 73 80
65 73 80 65 73 80
----------------------------------------------------------------------------------------------------------------
Affected Designated Occupation 11.0 18.0 25.0 3.7 9.8 21.0 1.8 5.1 12.0
Miners \c\....................
Affected Non-Designated 1.4 2.3 3.3 0.5 1.3 2.7 0.2 0.7 1.5
Occupation Miners \d\.........
----------------------------------------------------------------------------------------------------------------
\a\ Simple CWP: Simple coal workers' pneumoconiosis.
\b\ PMF: Progressive massive fibrosis.
\c\ Affected Designated Occupation (DO) Miners: Includes all miners who work at the 56-percent of the Mechanized
Mining Units under consideration and who are exposed to dust concentrations similar to the DO, over a 45-year
occupational lifetime.
\d\ Affected Non-Designated Occupation (Non-DO) Miners: Includes all underground faceworkers under consideration
who are not classified as the DO.
VII. Significance of Risk
The criteria for evaluating the evidence to determine whether these
proposed standards improve the regulatory strategy for controlling
exposures to respirable coal mine dust are established by the Mine Act
pursuant to section 101(a)(6)(A) (30 U.S.C. 811(a)(6)(A))which provides
that:
The Secretary, in promulgating mandatory standards dealing with
toxic materials or harmful physical agents under this subsection,
shall set standards which most adequately assure on the basis of the
best available evidence that no miner will suffer material
impairment of health or functional capacity even if such miner has
regular exposure to the hazards dealt with by such standard for the
period of his working life.
Based on Court interpretations of similar language under the
Occupational Safety and Health Act, there are three questions that must
be addressed: (1) Whether health effects associated with the current
pattern of overexposures on individual shifts constitute a material
impairment to miner health or functional capacity; (2) whether the
current pattern of overexposures on individual shifts places miners at
a significant risk of incurring any of these material impairments; and
(3) whether the proposed rules would substantially reduce those risks.
The statutory criteria for evaluating the health evidence do not
require MSHA to wait for absolute certainty and precision. MSHA is
required to use the ``best available evidence'' (section 101(a)(6)(A)
of the Mine Act (30 U.S.C. 811(a)(6)(A)). The need to evaluate risk
does not mean that an agency is placed into a ``mathematical
straightjacket.'' See Industrial Union Department, AFL-CIO v. American
Petroleum Institute, 448 U.S. 607, 100 S.Ct 2844 (1980), otherwise
known as the ``Benzene'' decision. When regulating on the edge of
scientific knowledge, certainty may not be possible and,
so long as they are supported by a body of reputable scientific
thought, the Agency is free to use conservative assumptions in
interpreting the data . . . risking error on the
[[Page 42163]]
side of overprotection rather than underprotection (Id at 656).
We have taken steps in our quantitative risk assessment to conduct
a balanced analysis using available data. Some of our assumptions were
conservative, others were not.\19\
---------------------------------------------------------------------------
\19\ Following terminology used in the Benzene Decision, a
``conservative'' assumption is one that results in more protection
for miners than a less conservative assumption. Therefore, estimated
benefits are greater under assumptions that are ``conservative'' in
this sense.
---------------------------------------------------------------------------
In identifying the number and percentage of MMUs exhibiting a
pattern of recurrent overexposures on individual shifts we chose to
include only those MMUs with two or more 1999-operator bimonthly
samples in excess of the applicable standard, rather than the
population of MMUs with any overexposures.\20\ Also, the Quantitative
Risk Assessment estimates of reduction in risk are averages across MMUs
exhibiting a pattern of recurrent overexposures. For those miners who
work at mines exhibiting a pattern of recurrent overexposures which
differs from the one applied in the Quantitative Risk Assessment, their
reduction in risk would be more than or less than the expected average,
depending on whether or not their overexposures are at a higher or
lower than average rate and intensity.
---------------------------------------------------------------------------
\20\ By ``exhibiting a pattern of recurrent overexposures,''
means that, at a 95-percent confidence level, the applicable
standard is exceeded on at least six shifts per year.
---------------------------------------------------------------------------
Another important decision impacting choice in this risk assessment
involves the use of the traditional coal miner work schedule of 48-
weeks per year. Many of today's miners work longer hours per day,
month, and year than the traditional work schedule. These longer work
hours increase miners' cumulative exposure to respirable coal mine dust
beyond the parameters of exposure used in our estimates of risk. Even
so, to the extent that a proportion of miners may have a more limited
work schedule (and occupational exposure), either in number of years,
weeks per year, or hours per week, their expected benefit would have to
be adjusted downward, all other variables being constant.
Also, because of heavy, physical work, some miners may work at
ventilatory rates in excess of the above-cited 10 cubic meters per 8-
hour shift; an estimate of this ventilatory rate is 13.5 cubic meters
per 8-hour shift (ICRP, 1994). The sub-population of miners with higher
breathing rates would inhale more respirable coal mine dust than would
otherwise occur given the same environmental exposures, thereby
increasing their risks for the development of simple CWP and PMF.
In the QRA, to estimate average reduction in exposure, we chose the
best available data sets: 1999 operator bimonthly samples for DOs and
NDOs, respectively. Currently, both operator bimonthly and inspector
samples \21\ may be taken on production shifts that may not reflect
typical production levels. \22\ Although other factors may mediate the
amount of airborne respirable dust such as, ventilation and water
sprays, on average, higher production is correlated with increased
quantities of airborne respirable coal mine dust (Webster, et al.,
1990; Haney, et al., 1993; O'Green, et al., 1994). Some previous
commenters and the Dust Advisory Committee have alleged that operators
tend to reduce production and/or increase dust controls on sampled
shifts. To the extent that our values underestimate the true reduction
in respirable coal mine dust exposures, we have underestimated the
benefits of these rules.
---------------------------------------------------------------------------
\21\ Valid MSHA inspector samples require production to be at
least 60-percent of the average production for the last 30-days.
Valid operator bimonthly samples must be taken on a normal
production shift (i.e., a production shift during which the amount
of material produced in an MMU is at least 56 percent of the average
production reported for the last set of five valid samples) (30 CFR
70.101).
\22\ Therefore assuming representative operating conditions on
these shifts, in our QRA the results were extrapolated to all
production shifts, including those that were not sampled, at those
same 704 MMUs.
---------------------------------------------------------------------------
Based on MSHA's and NIOSH's experience and expertise, and previous
comments, we believe the production levels observed on sampling shifts
are indeed lower than typical (See discussion in Benefits section). We
also believe at some MMUs, more engineering controls at higher levels
of efficacy are used during sampling shifts than on the majority of
shifts (See discussion in Benefits section). Thus, it is reasonable to
conclude that the number of MMUs exhibiting a pattern of recurrent
overexposures is greater than the 704 captured in this Quantitative
Risk Assessment. Furthermore, the severity and rate of overexposures to
respirable coal mine dust among the 704 MMUs exhibiting a pattern of
recurrent overexposures are probably also greater than we have
estimated. We have derived our best estimate of the reduced risk using
the best available data. Yet due to limitations in the data, we believe
that we have underestimated the magnitude and frequency of typical
respirable coal mine exposures. To the extent that our values
underestimate the true reduction in respirable coal mine dust
exposures, we have underestimated the benefits of these rules.
Other aspects of our risk assessment methodology reflect more
conservative choices including the selection of an occupational
lifetime of 45-years. Various factors may affect the consistency of the
type and duration of jobs miners hold and hence their associated
cumulative exposure levels. For example, some miners who lose their
jobs upon mine closure are employed by other mines, sometimes in less-
exposed jobs. Some miners may chose to move from job to job over their
careers at underground coal mines, sometimes preferring positions away
from the mining face. Moreover, if the trend of increasing
mechanization continues, there will be fewer miners, and for some of
them, their occupational lifetimes will be shorter.
For reasons already explained, we believe these choices are
appropriate for this risk assessment. We also recognize that use of the
most conservative approach at every step of the risk assessment
analysis could produce mathematical risk estimates which, because of
the additive effect of multiple conservative assumptions, may overstate
the likely risk. We believe this QRA for simple CWP and PMF strikes a
reasonable balance based on available data. To the extent that we may
have underestimated the magnitude of overexposures which would be
prevented, we believe the actual benefits to be greater than we have
estimated.
It should be noted that reductions in the prevalence of simple CWP
and PMF attributable to eliminating individual shift overexposures are
not expected to materialize immediately after the overexposures have
been substantially reduced or eliminated. Because these diseases
typically arise after many years of cumulative exposure, allowing for a
period of latency, the beneficial effects of reducing exposures are
expected to become evident only after a sufficient time has passed that
the reduction in cumulative exposure could have its effect. The total
realized benefits would not be fully evident until after the youngest
of today's underground coal miners retire.
VIII. Feasibility Issues
Section 101(a)(6)(A) of the Mine Act (30 U.S.C. 811(a)(6)(A))
requires the Secretary of Labor to set standards which most adequately
assure, on the basis of the best available evidence, that no miner will
suffer material impairment of health or functional capacity even if
such miner has regular exposure to such hazards dealt with by
[[Page 42164]]
such standard over his or her working lifetime. Standards promulgated
under this section must be based upon research, demonstrations,
experiments, and such other information as may be appropriate. MSHA, in
setting health standards, is required to achieve the highest degree of
health and safety protection for the miner, and must consider the
latest available scientific data in the field, the feasibility of the
standards, and experience gained under this and other health and safety
laws.
In relation to promulgating health standards, the legislative
history of the Mine Act states that:
* * * This section further provides that ``other
considerations'' in the setting of health standards are ``the latest
available scientific data in this field, the feasibility of the
standards, and experience gained under this and other health and
safety laws.'' While feasibility of the standard may be taken into
consideration with respect to engineering controls, this factor
should have a substantially less significant role. Thus, the
Secretary may appropriately consider the state of the engineering
art in industry at the time the standard is promulgated.
* * * * *
Similarly, information on the economic impact of a health standard
which is provided to the Secretary of Labor at a hearing or during
the public comment period, may be given weight by the Secretary. In
adopting the language of section 102(a)(5)(A), the Committee wishes
to emphasize that it rejects the view that cost benefit ratios alone
may be the basis for depriving miners of the health protection which
the law was intended to insure.
S. Rep. No. 95-181, at 21-22 (1977), reprinted in 1977 U.S.C.C.A.N.
3421-22.
In American Textile Manufacturers' Institute v. Donovan, 452 U.S.
490, 508-509 (1981), the Supreme Court defined the word ``feasible'' as
``capable of being done, executed, or effected.'' The Court further
stated, however, that a standard would not be considered economically
feasible if an entire industry's competitive structure were threatened.
In promulgating standards, hard and precise predictions from agencies
regarding feasibility are not required.
A. Technological Feasibility
MSHA believes that the plan verification rule would be
technologically feasible for the mining industry. An agency must show
that modern technology has at least conceived some industrial
strategies or devices that are likely to be capable of meeting the
standard, and which industry is generally capable of adopting. American
Iron and Steel Institute v. OSHA, (AISI-II) 939 F.2d 975, 980 (D.C.
Cir. 1991); American Iron and Steel Institute v. OSHA, (AISI-I) 577
F.2d 825 (3d Cir. 1978) at 832-835; and Industrial Union Dep't., AFL-
CIO v. Hodgson, 499 F.2d 467, 478 (D.C. Cir. 1974).
In designing the plan verification rule, MSHA has taken into
account its experience and those of the operators to ensure that the
rule provides additional protection from occupational exposure to
respirable coal mine dust using current compliance technology (while
encouraging technological improvements). For this reason, MSHA believes
the proposed plan verification rule is technologically feasible. MSHA
requires mine operators to utilize all feasible engineering or
environmental controls, which are specified in the mine ventilation
plan, to maintain concentrations of respirable dust in the work
environment of MMUs at or below the applicable dust standard. Mine
operators therefore would not be required to implement engineering or
environmental controls that were not technologically feasible.
Based on its vast experience in the sampling of respirable dust
levels in the MMU work environment, MSHA believes that technology is
currently available to control respirable dust to levels at or below
the applicable level at MMUs employing continuous and conventional
methods of mining. However, MSHA recognizes that, unlike other mining
systems, longwall MMUs may have acute dust problems caused by the face-
ventilation airstream carrying the shearer-generated face dust over the
miners working downwind along the face. In these high-production
longwall MMUs, improvements in dust control technology have not kept
pace with increases in production technology. For this reason, the
proposed plan verification rule would allow longwall operators who have
trouble in meeting MSHA's respirable dust standard and who have
exhausted all feasible engineering and environmental controls to use
administrative controls or loose-fitting powered air-purifying
respirators (PAPRs), until other feasible controls become available.
B. Economic Feasibility
The plan verification rule would clearly be economically feasible
for the underground coal mining industry since the underground coal
mining industry would derive net compliance cost savings of
approximately $2.04 million yearly from the proposed plan verification
rule. (Although implementing the plan verification rule would cost
about $4.75 million yearly, there would be the following offsetting
yearly savings: $2.19 million from reduced mine operator citations
based on results from inspector single, full-shift samples and
associated abatement sampling, $1.61 million from reduced mine operator
citations on results from operators' bi-monthly samples and associated
abatement sampling, $2.73 million from the elimination of operator bi-
monthly sampling, and $0.27 million from reduced payouts by mine
operators for Black Lung cases.) Underground coal mine operators would
also obtain a yearly cost savings of approximately $0.42 million in
reduced penalty costs associated with the reduction in mine operator
citations arising from the proposed plan verification rule. The
proposed plan verification rule would therefore provide a total yearly
cost savings of about $2.46 million to the underground coal mining
industry.
IX. Regulatory Impact Analysis
MSHA's improved program to eliminate overexposures on each and
every shift includes (1) the simultaneous implementation of the use of
inspector single, full-shift respirable coal mine dust samples to
identify overexposures more effectively in both underground and surface
coal mines (single, full-shift sample), and (2) in underground coal
mines, verified ventilation plans to maintain miners' respirable dust
exposure at or below the applicable standard on each and every shift
(plan verification). The single, full-shift sample NPRM is published
elsewhere in today's Federal Register. This part of the preamble
reviews several impact analyses which MSHA is required to provide in
connection with the proposed plan verification rulemaking. Since
single, full-shift sample and plan verification are complementary NPRMs
intended to be promulgated at the same time, the detailed presentation
of assumptions and estimates for each are available in the same
Preliminary Regulatory Economic Analysis (PREA)(MSHA, January 2000).
Assumptions for the requirements of the plan verification rule are
based upon information provided by MSHA technical personnel. We
encourage the mining community to provide detailed comments in this
regard to ensure that plan verification cost assumptions and estimates
are as accurate as possible.
A. Costs and Benefits: Executive Order 12866
In accordance with Executive Order 12866, we have prepared a
detailed PREA of the estimated costs and benefits associated with the
proposed rule for the underground coal mining sector. We have fulfilled
this
[[Page 42165]]
requirement for the proposed rule and determined that this rulemaking
is not a significant regulatory action. The key findings of the PREA
are summarized below.
1. Compliance Costs
The proposed plan verification rule would provide yearly net
compliance cost savings to underground coal mine operators of about
$2.04 million. Although implementing the proposed rule would cost about
$4.75 million yearly, there would be offsetting yearly savings of:
$2.19 million from reduced mine operator citations issued based on MSHA
inspectors' single, full-shift sample results and the elimination of
associated underground operator abatement sampling; $1.61 million from
reduced mine operator citations issued based on bi-monthly sampling
results and the elimination of associated underground operator
abatement sampling; $2.73 million resulting from underground operators
no longer having to perform bi-monthly operator sampling; and $0.27
million from reduced payouts by mine operators for Black Lung cases.
Table IX-1 summarizes the estimated net compliance costs by
provision for underground coal mines, for the following three mine size
categories: (1) those employing fewer than 20 workers; (2) those
employing between 20 and 500 workers; and (3) those employing more than
500 workers.
In addition to these estimated compliance costs, mine operators
would derive yearly penalty cost reductions of about $0.4 million (See
Table IX-1(a)). Penalty costs conventionally are not considered to be a
cost of a rule (and, in fact, are clearly not a compliance cost) but
merely a transfer payment from a party violating a rule to the
government. Therefore, the penalty costs are not included as part of
the compliance costs of the proposed plan verification rule. These
penalty costs are relevant, however, in determining the economic
feasibility of the proposed plan verification rule.
The derivation of the above cost figures are presented in Chapter
IV of the PREA that accompanies this rule.
[[Page 42166]]
Table IX-1.--PV Cost Summary for Underground Coal Mine Operators*
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
20 Emp. <gr-thn-eq>20 Emp. <ls-thn-eq>500 >500 Emp. Total
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
Detail Adj. first Annualized Annual Yearly Adj. first Annualized Annual Yearly Adj. first Annualized Annual Yearly Adj. first Annualized Annual Yearly
year costs costs costs costs \a\ year costs costs costs costs \a\ Year costs costs costs Costs \a\ year costs costs costs costs \a\
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
UNDERGROUND COAL MINES
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
PV Rule:
Compliance Costs....................................... $1,013,905 $70,973 $346,688 $417,661 $7,599,324 $566,960 $3,285,067 $3,852,027 $749,927 $58,653 $420,105 $478,758 $9,363,156 $696,586 $4,051,860 $4,748,446
Reduced Inspector Citations \b\........................ $234,374 $16,406 -$534,712 -$518,306 $746,981 $52,289 -$1,658,063 -$1,605,774 $33,603 $2,352 -$71,301 -$68,949 $1,014,958 $71,047 -$2,264,076 -$2,193,029
Reduced Operator Citations \c\......................... $106,512 $7,456 -$247,790 -$240,334 $596,040 $41,723 -$1,334,380 -$1,292,657 $39,325 $2,753 -$76,901 -$74,148 $741,877 $51,932 -$1,659,071 -$1,607,139
Eliminate Bi-Mo.--Sampling............................. $0 $0 -$556,538 -$556,530 $0 $0 -$2,057,540 -$2,057,540 $0 $0 -$113,712 -$113,712 $0 $0 -$2,727,790 -$2,727,790
Black Lung Savings..................................... $0 $0 -$32,570 -$32,570 $0 $0 -$217,896 -$217,896 $0 $0 -$15,196 -$15,196 $0 $0 -$265,662 -$265,662
Net PV Rule................................................ $1,354,791 $94,835 -$1,024,922 -$930,345 $8,942,345 $660,972 -$1,982,812 -$1,321,840 $822,855 $63,758 $142,995 $206,753 $11,119,991 $819,565 -$2,864,739 -$2,045,174
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
*Data from Preliminary Regulatory Economic Analysis Table IV-16, Table IV-63, Table IV-81, Table IV-100, Table IV-105, and Table IV-106. Note that these costs do not include penalty costs, which are shown in Table IX-1(a) in this document.
\a\ Yearly costs equals annualized costs plus annual costs.
\b\ Reduced costs related to: (1) Reduction in citations issued based on MSHA inspector sample results due to better mine ventilation plans arising from PV rule, and (2) reduction in abatement sampling and associated costs due to elimination of bi-monthly operator
sampling.
\c\ Reduced costs related to: (1) Reduction in citations issued based on operator sample results due to better mine ventilation plans arising from the PV rule, and (2) reduction in abatement sampling and associated costs due to elimination of operator bi-monthly sampling.
[[Page 42167]]
Table IX-1(A).--PV Annual Penalty Cost Summary *
[Yearly penalties]
----------------------------------------------------------------------------------------------------------------
<gr-thn-eq>20
Detail 20 Emp. Emp. <ls-thn- >500 Emp. Total
eq>500
----------------------------------------------------------------------------------------------------------------
Underground Coal Mines
----------------------------------------------------------------------------------------------------------------
PV Rule:
Reduced Inspector Citations................. -$28,468 -$202,334 -$5,263 -$236,065
Reduced Operator Citations.................. -13,309 -160,956 -4,960 -179,225
¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬¬
Total PV Rule Reduction......................... -41,777 -363,290 -10,223 -415,290
----------------------------------------------------------------------------------------------------------------
\*\ Data from Preliminary Regulatory Economic Analysis Table IV-16(a), Table IV-82, and Table IV-101.
2. Benefits
Occupational exposure to excessive levels of respirable coal mine
dust imposes significant health risks. These include the following
adverse health outcomes: simple coal worker's pneumoconiosis (simple
CWP), progressive massive fibrosis (PMF), silicosis, and chronic
obstructive pulmonary disease (COPD) (e.g., asthma, chronic bronchitis,
emphysema) (See the Health Effects section for details). Cumulative
exposure to respirable coal mine dust is the main determinant in the
development of both simple CWP and PMF although other factors such as
the percentage of quartz in the respirable dust and the type of coal
also affect the risk of miners developing simple CWP and PMF (Jacobsen,
et al., 1977; Hurley, et al., 1987; Kuempel, et al., 1995; Attfield and
Morring, 1992; Attfield and Seixas, 1995). The true magnitude of
occupationally induced simple CWP and PMF among today's coal miners is
unknown, although prevalence estimates are available from various
surveillance systems. For example, from 1970 to 1995, the prevalence of
simple CWP and PMF among miners, based on the operator sponsored x-ray
program, dropped from 11 percent to 3 percent (MSHA, Internal Chart,
1998). Also, later rounds of the National Study for Coal Worker's
Pneumoconiosis consistently demonstrated, through prevalence rates in
the range of 2.9--3.9 percent, that simple CWP and PMF have not been
eliminated.
Through the joint promulgation of single, full-shift sample and
plan verification rules, miners would be further protected from the
debilitating effects of occupational respiratory disease by limiting
their exposures to respirable coal mine dust to no more than the
applicable standard on each and every shift.\23\ Reducing respirable
coal mine dust concentrations over a 45-year occupational lifetime to
no more than the applicable standard on just that percentage of shifts
showing an excess would lower the cumulative exposure, thereby
significantly reducing the risk of both simple CWP and PMF among
miners. We have estimated the health benefits of the two rules arising
from the elimination of overexposures on all shifts at only those MMUs
exhibiting a pattern of recurrent overexposures on individual shifts.
---------------------------------------------------------------------------
\23\ For details, see Quantitative Risk Assessment and
Significance of Risk sections.
---------------------------------------------------------------------------
Based on 1999 operator data, there were 704 MMUs (out of 1,251) at
which regular (not abatement) designated occupational (DO) samples
exceeded the applicable standard on at least two of the sampling shifts
reported in 1999 (MSHA, Data file:Operator.ZIP). MSHA considers these
704 MMUs, representing more than one-half of all underground coal
miners working in production areas, to have exhibited a pattern of
recurrent overexposures. Based on valid DO operator samples were
collected on a total of 18,569 shifts at these 704 MMUs; the applicable
standard was exceeded on 3,977 of these shifts or 21.4 percent.
At the MMUs being considered (those exhibiting a pattern of
recurrent overexposures),\24\ bringing dust concentrations down to no
more than the applicable standard on each and every production shift
would reduce DO exposures on the affected shifts by an average of 1.04
mg/m\3\. Assuming this average reduction applies to only 21 percent of
the shifts, the effect would be to reduce cumulative exposure, for each
miner exposed at or above the DO level, by 0.22 mg-yr/m\3\ over the
course of a working year (i.e., 21 percent of shifts in one year times
1.04 mg/m\3\ per shift). Therefore, over a 45-year working lifetime,
the benefit to each affected DO miner would, on average, amount to a
reduction in accumulated exposure of approximately 10 mg-yr/m\3\ (i.e.,
45 years times 0.22 mg-yr/m\3\ per year). If, as some miners have
testified, operator dust samples submitted to MSHA tend to under-
represent either the frequency or magnitude (or both) of individual
full-shift excursions above the applicable standard, then eliminating
such excursions would provide a lifetime reduction of even more than 10
mg-yr/m\3\ for each exposed miner.
---------------------------------------------------------------------------
\24\ MSHA estimates an MMU average of 384 production shifts per
year. Since miner operators are required to submit five valid
designated operator (DO samples to MSHA every two months, there
would typically be 30 valid DO samples--for each MMU that was in
operation for the full year. If dust concentrations on two or more
of the sampled shifts exceed the standard, then it follows, at a 95-
percent confidence level, that the standard was exceeded on at least
six shifts over the full year.
---------------------------------------------------------------------------
When the dust concentration measured for the DO exceeds the
applicable standard, measurements for at least some of the other miners
working in the same MMU may also exceed the standard on the same shift,
though usually by a smaller amount. Furthermore, although the DO
represents the occupation most likely to receive the highest exposure,
other miners working in the same MMU may be exposed to even higher
concentrations than the DO on some shifts. Therefore, in addition to
the affected DO miners, there is a population of other affected miners
who are also expected to experience a significant reduction in risk as
a result of eliminating overexposures on their individual shifts.
To estimate how many miners other than the DO would be
substantially affected, MSHA examined the results from all valid dust
samples collected by MSHA inspectors in underground MMUs during 1999
(MSHA, Data file: Inspctor.zip). Within each MMU, the inspector
typically takes one full-shift sample on the DO and, on the same shift,
four or more additional samples representing other occupations. On 896
shifts, at a total of 450 distinct MMUs, the DO measurement exceeded
the applicable standard and there were at least three valid
measurements for other occupations available for comparison. There was
an average of 1.2 non-DO
[[Page 42168]]
measurements in excess of the standard on shifts for which the DO
measurement exceeded the standard.\25\ For non-DO measurements that
exceeded the standard on the same shift as a DO measurement, the mean
excess above the standard was approximately (0.8 mg/m\3\).\26\
---------------------------------------------------------------------------
\25\ With 95-percent confidence, on shifts for which the DO
measurement exceeds the standard, the mean number of other
occupational measurements also exceeding the standard is at least
1.11.
\26\ With 95-percent confidence, the mean excess is at least
0.72 mg/m \3\.
---------------------------------------------------------------------------
Combining these results with the 21-percent rate of excessive
exposures observed for the DO on individual shifts, it is reasonable to
infer that, at the MMUs under consideration, an average of 1.2 other
miners, in addition to the one classified as DO, is overexposed on at
least 21 percent of all production shifts. Over the course of a working
year, the reduction in exposure expected for these affected non-
designated occupational (NDO) miners, is 0.17 mg-yr/m\3\ (i.e., 21
percent of one year, times 0.8 mg/m\3\).
The expected lifetime for all American males, conditional on their
having reached 20 years of age, is 73 years (U.S. Census March 1997,
Table 18; U.S. Census March 1997, Table 119).\27\ On average, the best
estimate of the lifetime benefit to exposed miners is expressed by the
reduction in prevalence of disease at age 73. To project the reduction
in risk of simple CWP and PMF among affected DOs and NDOs, MSHA applied
its best estimate of dose response to a hypothetical cohort of
underground coal miners who work on an MMU exhibiting a pattern of
recurrent overexposure, and who, on average, begin working at age 20,
retire at age 65, and live to age 73.\28\ Strengths and weaknesses of
various epidemiological studies were presented in the Health Effects
section supporting the selection of Attfield and Seixas (1995) as the
study that provides the best available estimate of material impairment
with respect to simple CWP and PMF. Two of the distinguishing qualities
of Attfield and Seixas (1995) are the dose-response relationship over a
miner's lifetime and the fact that these data best represent the recent
conditions experienced by miners in the U.S. Using this relationship,
it is possible to evaluate the impact on risk of both simple CWP and
PMF expected from bringing respirable coal mine dust concentrations
down to or below the applicable standard on every shift. This is the
only contemporary epidemiological study of simple CWP and PMF providing
such a relationship.
---------------------------------------------------------------------------
\27\ Since females have a greater life expectancy than males,
the expected benefits would increase if the proportion of female
miners were to increase substantially in the future.
\28\ If a different definition of ``exhibiting a recurrent
pattern of overexposures'' were used in these analyses, the estimate
of the reduction in risk and associated benefits would be different.
For example, if the criterion were that four or more DO bimonthly
exposure measurements exceeded the applicable standard, we could
state, with 95% confidence, that the standard was exceeded on at
least 20 shifts in a year of 384 shifts. Using four as the criterion
would reduce the population for whom we are estimating benefits, and
decrease the estimated number of prevented cases by 19%.
---------------------------------------------------------------------------
To estimate the benefits (i.e., number of cases of simple CWP and
PMF prevented) of single, full-shift sample and plan verification
combined, we applied these estimates of risk reduction to the estimated
sub-populations of affected miners. As of February 12, 1999, there were
984 producing MMUs;\29\ applying the pattern of recurrent overexposures
among MMUs as identified in the Quantitative Risk Assessment, 56
percent, by mine size, we estimate there to be 552 affected MMUs (MSHA
Table, November 18, 1999; MSHA Table, February 12, 1999). Based on
MSHA's experience, we would expect one DO and seven NDOs for each shift
of production at each MMU. Therefore, among underground coal miners
working on an MMU, we estimate 12.5% to be designated occupational
miners and 87.5% to be non-designated occupational miners.
---------------------------------------------------------------------------
\29\ Nine hundred and eighty-four refers to the number of MMUs
operating on February 12, 1999. The 1,443 number mentioned
previously refers to all MMUs in operation at any time in 1999.
---------------------------------------------------------------------------
The benefits that will accrue to coal miners exposed to respirable
coal mine dust and to mine operators, and ultimately to society at
large, are substantial and take a number of forms. These proposed rules
would reduce a significant health risk to underground coal miners,
reducing the potential for illnesses and premature death and their
attendant costs to miners, their employers, their families, and
society.
The joint promulgation of these rules should realize a positive
economic impact on the Department of Labor's (DOL's) Black Lung Program
and relatedly on mine operators. The Black Lung Program compensates
eligible miners, and their survivors under the Black Lung Benefits Act.
This program provides monthly payments and medical benefits (diagnostic
and treatment) to miners who are found to be totally disabled by black
lung disease, including cases of PMF and simple CWP. In 1986, DOL's
Employment Standards Administration reported that 12% of approved cases
of Black Lung Program were identified as cases of PMF based on chest
radiographs, while sixty-four percent had simple CWP based on chest
radiographs. For miners who stopped working in coal mines after 1969
and for whom the DOL can establish that the miner worked for the same
operator for at least one calendar year, and that miner had at least
125 working days in that year, that operator is financially responsible
for the miner's Black Lung benefit payment. If a responsible operator
cannot be identified for an eligible miner, benefit payments are made
by the Black Lung Disability Trust Fund. To the extent that these rules
reduce overexposures to respirable coal mine dust, there should be
fewer Black Lung Program cases. Therefore, over time, the associated
financial outlay by responsible operators through either insurance
premiums or direct payments of Black Lung benefits should be lower than
would otherwise occur. The financial impact could be substantial see
discussion in Chapter IV, of the PREA. In 1980, the Black Lung Program
estimated average lifetime pay-outs for responsible operators for
married miners of about $248,700 dollars, assuming a 7 percent annual
rate increase (ESA, 1980). In fiscal year 1999, 443 claims for Black
Lung Benefits were accepted as new cases; sixty-six percent (293) are
the financial responsibility of coal mine operators (Peed, 2000).
Table IX-2 presents the estimated number of cases of simple CWP and
PMF that would be prevented among the 56 percent of MMUs exhibiting a
pattern of recurrent overexposures. For all categories of simple CWP
and PMF combined, we estimate 37 fewer of these cases, among affected
miners, than would otherwise occur without the promulgation of single,
full-shift sample and plan verification rules. Eleven of these cases
would be the most severe form of coal miners pneumoconiosis, PMF, and
as such this benefit could be interpreted as prevented premature deaths
due to occupational exposure to respirable coal mine dust. Since simple
CWP predisposes the development of PMF, it is important that it also be
prevented (Balaan, et al., 1993).
As discussed in the Significance of Risk sections, MSHA believes
this QRA for simple CWP and PMF strikes a reasonable balance based on
available data. Yet, our estimates likely understate the true impact of
these rules since our analyses are restricted to a sub-population of
affected miners, those working at MMUs exhibiting a pattern of
recurrent overexposures, not the broader population of coal miners who
will benefit from these rules. Furthermore, to estimate the average
[[Page 42169]]
overexposure which would be prevented, MSHA had to use data collected
for compliance purposes which may not represent typical environmental
conditions.
The degree to which the exposure level of respirable coal mine dust
on sampling shifts may not be representative of typical exposure levels
is affected by the following factors:
(1) There exists a positive relationship between coal production
and generation of respirable coal mine dust;
(2) Current sampling procedures permit sampling measurements to be
taken at the mid-range of the distribution of level of production--
sampling measurements must be taken on shifts with production at least
60% of the average production during the last 30 days and at least 50%
of average production for the last valid set of bimonthly samples for
inspector and operator samples, respectively;
(3) Miners have reported and MSHA data have demonstrated lower
levels of production on sampling shifts versus non-sampling shifts
(MSHA, September 1993);
(4) On some sampling shifts, miners have reported that more
engineering controls may be used than on other shifts, thus reducing
the measured amount of respirable coal mine dust;
(5) MSHA analyses have demonstrated, even when controlling for
production, in mines with fewer than 125 employees, on continuous
mining MMUs, respirable coal mine dust exposures were much higher
during the unannounced Spot Inspection Program (SIP) sampling shifts
than on shifts operators sampled--this is consistent with the effect of
increasing engineering controls on shifts during which bimonthly
samples are conducted compared to the level of use of engineering
controls used on shifts for which the operator does not expect sampling
to be conducted given the same production level (Denk, 1993);
(6) Across mine size, designated area samples have been found to be
larger for shifts on which unannounced compliance sampling occurred
compared to operator sampling shifts-- in one study they differed by at
least a factor of 40 percent in large mines and 100 percent in the
smallest mines (ibid. p 211-212); and
(7) Existing MSHA technical information indicates that some
reduction in production levels occurs during some sampling periods on
longwalls (Denk, 1990).
Therefore, at a bare minimum, over an occupational lifetime (45-
years) for miners who live to age 73 who worked at MMUs exhibiting a
pattern of recurrent overexposures, we estimate at least 37 fewer cases
of pneumoconiosis (simple coal workers pneumoconiosis (CWP) and
progressive massive fibrosis (PMF)) than would otherwise occur without
the promulgation of these rules.
Our current quantitative estimate of benefits demonstrates and
qualitative discussions punctuate that these rules will have a
significant positive impact on the health of our Nation's coal miners
when promulgated. Yet, due to the limitations on these data, we believe
our benefit estimate may understate the number of cases of simple CWP
and PMF which would be prevented over an occupational lifetime.
MSHA believes that cases of simple CWP and PMF would also be
prevented among other types of underground miners, such as roofbolters
working in designated areas (DA). Based on MSHA experience it is
reasonable to expect roofbolter DA's pattern of overexposures for
respirable coal mine dust to be similar to that for miners with the
highest exposure on an MMU. If so, we would expect 13 additional cases
of simple CWP and PMF to be prevented. Affected DAs include DAs who
work at the 56 percent of the MMUs under consideration who are exposed
to dust concentrations similar to the DO, over a 45-year occupational
lifetime (MSHA Table, November 18, 1999; MSHA Table, February 12,
1999).
Although the effect cannot readily be quantified, to the extent
that these rules would also reduce the cumulative exposure to
respirable coal mine dust among some miners working in those MMUs not
exhibiting overexposures, it is reasonable to expect that we would
observe an incremental benefit among that sub-population of coal
miners. Moreover, to the extent that the cumulative dust exposure is
reduced for miners working in the ``out by'' areas, away from the
mining face (i.e., MMU) where coal is extracted from the coal seam,
they too may realize occupational health benefits due to the
simultaneous promulgation of these proposals. Therefore, our best
estimate of 37 prevented cases of simple CWP and PMF, combined, among
all affected miners likely underestimates the true benefit realized by
the coal mining workforce through the reduction of overexposures to no
more than the applicable standard on each shift.
Clearly PMF is associated with premature death. Since simple CWP
may evolve to PMF, even after occupational exposure has ceased, it has
the propensity to become a life threatening illness. By reducing the
total number of simple CWP and PMF cases among affected miners from 259
to 222, over 45 years, these standards, at a minimum, are projected to
prevent an average of four cases of simple CWP and PMF for each 5-year
interval.\30\
---------------------------------------------------------------------------
\30\ Applying an estimated prevalence rate of 3.0 percent to the
estimated population of affected miners (8,640) results in an
estimate of 259 cases of simple CWP and PMF.
---------------------------------------------------------------------------
For all those reasons previously identified, MSHA believes that its
estimate of 37 prevented cases of simple CWP and PMF over a 45 year
working life understates the true number of cases of simple CWP and PMF
which would be prevented. This belief is further supported by the fact
that during the past few years, the Black Lung Benefits Program has
been approving roughly 400 claims each year. These claims come from
individuals whose exposure for the most part came after the current
standard of 2.0 was established in 1972. Thus, we believe the
consistent annual approval by the Black Lung Benefits Program, of
hundreds of new cases of simple CWP and PMF per year, supports our
belief that the true lifetime occupational health benefits of the
proposed rules are higher than we have estimated. Even assuming that
the number of new claims would decline in future years simply due to
the continuing decline in the number of coal miners, MSHA expects that
assuring that future exposures are maintained below the 2.0 exposure
limit will reduce the number of new cases of simple CWP and PMF by
considerably more than 1 per year.
In addition to the prevention of simple CWP and PMF, each of the
8,640 affected miners at MMUs exhibiting a pattern of recurrent
overexposures will realize some health benefit by limiting his or her
cumulative exposure to respirable coal mine dust to no more than the
applicable standard on each and every shift.
The expected number of prevented cases of simple CWP and PMF would
not be realized for some time even after the pattern of overexposures
has been minimized or eliminated. This is due, in part, to the
latency--that is, the disease does not develop immediately after
exposure--of the development of simple CWP and PMF and the pre-existing
occupational exposure histories of members of the current coal mining
workforce. Our estimated benefit is based on the estimated number of
underground coal miners working at the mine face, 17,280. If the size
of this workforce significantly changed in the future and the projected
pattern of prevented overexposures remained the same, the number of
cases of prevented
[[Page 42170]]
simple CWP and PMF would need to be adjusted to account for the change.
Various data, assumptions and caveats were used to conduct the
quantitative risk assessment, significance of risk discussion, and
benefits analyses. Therefore, we request any information which would
enable us to conduct more accurate analyses of the estimated health
benefits of the single, full-shift sample rule and plan verification
rule, both individually, and in combination.
Table IX-2.--Over a Working Lifetime Among Affected Miners, Estimated Number of Cases of CWP \a\ and PMF \b\
Prevented Due to the Implementation of Single, Full-Shift Sample and Plan Verification
----------------------------------------------------------------------------------------------------------------
Simple CWP categories Simple CWP categories PMF
1, 2, 3 or PMF 2 or 3 or PMF -----------------------
Type of Miner Affected ------------------------------------------------
Miners, n= Reduction Prevented Reduction Prevented Reduction Prevented
in risk cases, n= in risk cases, n= in risk Cases, n=
----------------------------------------------\c\---------------------\c\---------------------\c\---------------
Affected Designated 1,080 18/1000 19.4 9.8/1000 10.6 5.1/1000 5.5
Occupational Miners \d\....
Affected Non-Designated 7,560 2.3/1000 17.4 1.3/1000 9.8 0.7/1000 5.3
Occupational Miners \e\....
Total............... 8,640 NA 37 NA 20 NA 11
----------------------------------------------------------------------------------------------------------------
\a\ Simple CWP: Simple coal workers' pneumoconiosis.
\b\ PMF: Progressive massive fibrosis.
\c\ Reduction in risk per 1,000 affected miners, over a 45-year working lifetime.
\d\ Affected Designated Occupation (DO) Miners: Includes all miners who work at the 56-percent of the Mechanized
Mining Units under consideration and who are exposed to dust concentrations similar to the DO, over a 45-year
occupational lifetime.
\e\ Affected Non-Designated Occupation (Non-DO) Miners: Includes all underground faceworkers under consideration
who are not classified as the DO.
B. Regulatory Flexibility Certification and Initial Regulatory
Flexibility Analysis
The Regulatory Flexibility Act requires MSHA to conduct an analysis
of the effects of the proposed plan verification rule on small
entities. That analysis is summarized here; a copy of the full analysis
is included in Chapter V of our PREA in support of the proposed single,
full-shift sample and plan verification rules. We encourage the mining
community to provide comments on this analysis.
The Small Business Administration generally considers a small
entity in the mining industry to be one with 500 or fewer workers. MSHA
has traditionally defined a small mine to be one with fewer than 20
workers, and has focused special attention on the problems experienced
by such mines in implementing safety and health rules. Accordingly, we
have separately analyzed the impact of the joint notice proposed rule
both on mines with 500 or fewer workers and on those with fewer than 20
workers.
Pursuant to the Regulatory Flexibility Act, MSHA must determine
whether the costs of the joint notice proposed rule constitute a
``significant impact on a substantial number of small entities.''
Pursuant to the Regulatory Flexibility Act, if an Agency determines
that a proposed rule would not have such an impact, it must publish a
``certification'' to that effect. In such a case, no additional
analysis is required (5 U.S.C. Sec. 605). In evaluating whether
certification is appropriate, MSHA utilized a ``screening test,''
comparing the costs of the proposed plan verification rule to the
revenues of the affected coal sector. If the estimated costs are less
than 1 percent of revenues for the affected entities, or they are
negative (that is, they provide a cost savings), then the rule is
assumed not to have a significant impact on small mine operators.
Table IX-3 compares, for small underground coal mines (using both
MSHA's and SBA's definition), MSHA's estimated total annual compliance
costs of the proposed plan verification rule to estimated annual
revenues.
Table IX-3 shows that under either MSHA's or SBA's definition of a
small mine, the proposed plan verification rule would provide a net
cost savings to small underground coal mines. As a result, MSHA is
certifying that the proposed plan verification rule for underground
coal mines would not have a ``significant impact on a substantial
number of small entities,'' and has performed no further analyses.
Table IX-3.--Estimated Yearly Costs of Proposed Plan Verification Rule Relative to Yearly Revenues for
Underground Coal Mines
[Dollars in thousands]
----------------------------------------------------------------------------------------------------------------
Underground Costs as
Mine size Proposed rule coal mine percentage of
net costs <SUP>a</SUP> revenues <SUP>b</SUP> revenues
----------------------------------------------------------------------------------------------------------------
20 employees................................................... ($930.1) $249,418 (0.4%)
500 employees <SUP>c</SUP>................................................ ($1,251.9) $6,883,339 (0.03%)
----------------------------------------------------------------------------------------------------------------
<SUP>a</SUP> Estimated yearly costs are composed of ``adjusted'' first year costs that have been annualized plus annual
costs.
<SUP>b</SUP> Data for revenues derived from: U.S. Department of Labor, Mine Safety and Health Administration, Office of
Standards, Regulations, and Variances, based on 1997 Final MIS data (quarter 1-quarter 4), CM441, cycle 1997/
184; and U.S. Department of Energy, Energy Information Administration, Annual Energy Review 1998, DOE/EIA-
0384(98), July 1999, p 203.
<SUP>c</SUP> Includes mines with fewer than 20 employees.
[[Page 42171]]
X. Other Statutory Requirements
A. Plain Language
We (MSHA) wrote appropriate portions of this proposed rule in the
more personal style advocated by the President's Memorandum on ``plain
language.'' ``Plain language'' encourages the use of personal pronouns
(we and you); sentences in the active voice; a greater use of headings,
lists, and questions, as well as charts, figures, and tables.
In this proposed rule, ``you'' refers to production-operators and
independent contractors because they have the primary responsibility
for compliance with MSHA regulations. In addition, we recognize and
appreciate the value of comments, ideas, and suggestions from labor
organizations, industry associations, and other parties who have an
interest in health and safety training for miners.
We would appreciate comments and suggestions from all parties on
this proposed rule and on our use of ``plain language.'' How could we
improve the clarity of this style?
B. Unfunded Mandates Reform Act of 1995
For purposes of the Unfunded Mandates Reform Act of 1995, this rule
does not include any Federal mandate that may result in increased
expenditures by State, local, and tribal governments, or increased
expenditures by the private sector of more than $100 million.
C. Paperwork Reduction Act of 1995
The proposed plan verification rule contains information
collections which are subject to review by the Office of Management and
Budget (OMB) under the Paperwork Reduction Act of 1995 (PRA95). The
proposed rule has first year burden hours (those that occur only in the
first year) and, annual burden hours which occur in the first year and
every year thereafter.
How some types of burden hours and costs were handled requires
explanation. In a few cases, the proposed plan verification rule
imposes burden hours and costs that would be the same every year,
beginning with the first year that the rule takes effect. These are
``annual'' burden hours and costs, as traditionally defined.
In most cases, however, the proposed plan verification rule imposes
burden hours and costs which would be the same each year starting with
the second year the proposed rule is in effect, but whose first year
burden hours and costs would be different. MSHA transformed these first
year burden hours and costs and annual burden hours and costs starting
in Year 2 into adjusted first year burden hours and costs (first year
burden hours and costs minus an amount equal to annual burden hours and
costs starting with Year 2 after the rule takes effect) and true annual
burden hours and costs starting in Year 1 after the rule takes
effect.\31\
---------------------------------------------------------------------------
\31\ A hypothetical example might help to explain this
procedure. Suppose that compliance costs are $2,000 the first year
and $400 each year thereafter. The adjustment procedure simply
splits first year compliance costs into two parts: (1) $400, for the
first year of annual costs; and (2) the residual $1,600.
Consequently, adjusted first year costs would be $1,600 and annual
costs (starting in year 1) would be $400.
---------------------------------------------------------------------------
First Year Burden Hours
In the first year the plan verification rule is in effect, there
would be a total net burden hour savings, for underground coal mine
operators, of 44,750, which is composed of 7,912 first year burden
hours (from Table X-1) and 52,662 annual burden hour savings (from
Table X-2). The 44,750 net burden hour savings have associated cost
savings of $847,236, which is composed of $360,820 of adjusted first
year costs (from Table X-1) and $1,208,056 of annual cost savings (from
Table X-2).
Annual Burden Hours in Second Year and Every Year Thereafter
There would be a total net annual burden hour savings, for
underground coal mine operators, in the second year the proposed plan
verification rule is in effect and every year thereafter of 52,662,
which has associated cost savings of approximately $1.21 million
annually (from Table X-2). These net burden hours and costs include
annual burden hour and cost savings due to: reduced mine operator
citations based on MSHA inspectors' single, full-shift sample results
and the elimination of associated operator abatement sampling; reduced
mine operator citations issued based on bi-monthly sampling results and
the elimination of associated operator abatement sampling; and savings
from operators no longer having to perform bi-monthly operator
sampling.
[[Page 42172]]
Table X-1.--Summary of PV Proposed Rule First Year Paperwork Burden Hours and Related Costs That Occur Only in the First Year*
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
20 emp. <gr-thn-eq>20 emp. <ls-thn-eq>500 >500 emp. Total
-----------------------------------------------------------------------------------------------------------------------------------------------------------
Adjusted Adjusted Adjusted adjusted
Detail Adjusted Adjusted first year Adjusted Adjusted first year Adusted Adjusted first year Adjusted Adjusted first year
first year first year costs first year first year costs first year first year costs first year first year costs
hours costs annualized hours costs annualized hours costs annualized hours costs annualized
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
UNDERGROUND COAL MINES
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
PV Rule:
Increase........................ 1,359 $61,059 $4,274 6,140 $280,581 $20,372 398 $18,425 $1,399 7,897 $360,065 $26,045
Reduced Inspector Citations \a\. 3 $151 $11 6 $302 $21 0 $0 $0 9 $453 $32
Reducted Operator citations \b\. 3 $151 $11 3 $151 $11 0 $0 0 6 $302 $22
Elimination of Bi-Mo. Sampling.. 0 $0 $0 0 $0 $0 0 $0 $0 0 $0 $0
Net PV Rule......................... 1,365 $61,361 $4,296 6,149 $281,034 $20,404 398 $18,425 $1,399 7,912 $360,820 $26,099
------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
* Source: Preliminary Regulatory Economic Analysis Tables VII-32, VII-43, and VII-53.
\a\ Related to reduced citations issued based on inspector sample results due to better mine ventilation plans arising from the PV rule.
\b\ Related to reduced citations issued based on operator sample results due to better mine ventilation plans arising from the PV rule.
[[Page 42173]]
Table X-2.--Summary of Annual Paperwork Burden Hours and Related Costs That Occur in the First Year and Every Year Thereafter *
--------------------------------------------------------------------------------------------------------------------------------------------------------
20 emp. <gr-thn-eq>20 emp. <ls- >500 emp. Total
-------------------------- thn-eq>500 ------------------------------------------------------
Detail --------------------------
Annual Annual Annual Annual Annual Annual Annual Annual costs
hours costs hours costs hours costs hours
--------------------------------------------------------------------------------------------------------------------------------------------------------
UNDERGROUND COAL MINES
--------------------------------------------------------------------------------------------------------------------------------------------------------
PV Rule:
Increase............................................................................................................................................
Reduced Inspector Citations \a\.....................................................................................................................
Reduced Operator Citations \b\......................................................................................................................
Elimination of Bi-Mo. Sampling......................................................................................................................
Net PV Rule.............................................................................................................................................
--------------------------------------------------------------------------------------------------------------------------------------------------------
\*\ Source: Preliminary Regulatory Economic Analysis Tables VII-7, VII-33, VII-43, VII-53, and VII-57.
\a\ Reduction related to: (1) Reduced citations issued based on inspector sample results due to better mine ventilation plans arising from the PV rule
and (2) reduced abatement sampling and associated costs due to the elimination of bi-monthly operator sampling.
\b\ Reduction related to: (1) Reduced citations issued based on operator sample results due to better mine ventilation plans arising from the PV rule
and (2) reduced abatement sampling and associated costs due to the elimination of bi-monthly operator sampling.
We invite public comments and are particularly interested in
comments which:
1. Evaluate whether the proposed collection of information
(presented here and in the PREA for the proposed single, full-shift
sample and plan verification rules) is necessary for the proper
performance of the functions of MSHA, including whether the information
will have practical utility;
2. Evaluate the accuracy of our estimate of the burden of the
proposed collection of information, including the validity of the
methodology and assumptions used;
3. Enhance the quality, utility, and clarity of the information to
be collected; and
4. Minimize the burden of the collection of information on
respondents, including through the use of appropriate automated,
electronic, mechanical, or other technological collection techniques or
other forms of information technology, e.g., permitting electronic
submissions of responses.
We have submitted a copy of this proposed rule to OMB for its
review and approval of these information collections. Interested
persons are requested to send comments regarding this information
collection, including suggestions for reducing this burden, to the
Office of Information and Regulatory Affairs, OMB New Executive Office
Building, 725 17th St., NW, Rm. 10235, Washington, DC 20503, Attn: Desk
Officer for MSHA. Submit written comments on the information collection
not later than September 5, 2000.
Our paperwork submission summarized above is explained in detail in
the PREA. The PREA includes the estimated costs and assumptions for
each proposed paperwork requirement related to this proposed rule. A
copy of the PREA is available from us. These paperwork requirements
have been submitted to the Office of Management and Budget for review
under section 3504(h) of the Paperwork Reduction Act of 1995.
Respondents are not required to respond to any collection of
information unless it displays a current valid OMB control number.
D. National Environmental Protection Act
The National Environmental Policy Act (NEPA) of 1969 requires each
Federal agency to consider the environmental effects of proposed
actions and to prepare an Environmental Impact Statement on major
actions significantly affecting the quality of the human environment.
We have reviewed the proposed standard in accordance with the
requirements of the NEPA (42 U.S.C. 4321 et seq.), the regulation of
the Council on Environmental Quality (40 CFR part 1500), and the
Department of Labor's NEPA procedures (29 CFR part 11). As a result of
this review, we have preliminarily determined that this proposed
standard will have no significant environmental impact.
Commenters are encouraged to submit their comments on this
determination.
E. Executive Order 12630 (Governmental Actions and Interference with
Constitutionally Protected Property Rights)
This proposed rule is not subject to Executive Order 12630,
Governmental Actions and Interference with Constitutionally Protected
Property Rights, because it does not involve implementation of a policy
with takings implications.
F. Executive Order 12988 (Civil Justice)
The Agency has reviewed Executive Order 12988, Civil Justice
Reform, and determined that this rulemaking will not unduly burden the
Federal court system. The regulation has been written so as to provide
a clear legal standard for affected conduct, and has been reviewed
carefully to eliminate drafting errors and ambiguities.
G. Executive Order 13045: Protection of Children from Environmental
Health Risks and Safety Risks
In accordance with Executive Order 13045, protection of children
from environmental health risks and safety risks, we have evaluated the
environmental health or safety effects of the proposed rule on
children. The Agency has determined that this proposal would not have
an adverse impact on children.
H. Executive Order 13084 (Consultation and Coordination With Indian
Tribal Governments)
We certify that this proposed rule does not impose substantial
direct compliance costs on Indian tribal governments.
I. Executive Order 13132 (Federalism)
We have reviewed this rule in accordance with Executive Order 13132
regarding federalism, and have determined that it does not have
``federalism implications.'' The rule does not ``have substantial
direct effects on the States, on the relationship between the national
government and the States, or on the distribution of
[[Page 42174]]
power and responsibilities among the various levels of government.''
XI. Public Hearings
MSHA plans to hold public hearings on the proposed rule. The
hearings will be held in Prestonsburg, Kentucky (Jenny Wiley, State
Resort Park); Morgantown, West Virginia; and Salt Lake City, Utah. The
hearing dates, times, and specific locations will be announced by a
separate document in the Federal Register. The hearings will be held
under Section 101 of the Federal Mine Safety and Health Act of 1977.
Appendix A--Derivation of the Critical Values
All measurements of respirable dust concentration are subject to
potential sampling and analytical errors. Because of such errors, a
measurement may fall slightly below the verification limit even when
the true concentration of respirable coal mine dust or crystalline
silica does not. Therefore, to ensure that the verification limits
have actually been met, it is necessary to provide for a margin of
error in each measurement. The critical values provide this margin
of error. When valid measurements do not exceed the appropriate
critical values, we can be confident that the verification limits
have not been exceeded at the sampled locations.
To explain how the verification limits were derived, it is
helpful to define some symbolic notation. Let X represent a
measurement, and let <greek-m> represent the true value of whatever
quantity is being measured--i.e., the full shift average
concentration, at a specific sampling location, of either respirable
coal mine dust or respirable crystalline silica dust. The difference
between X and <greek-m> is the measurement error and is denoted by
<greek-e>. X = <greek-m> + <greek-e>.
In accordance with standard statistical and industrial hygiene
practice, <greek-e> (but not <greek-m>) is assumed to be normally
distributed. Since the approved sampling and analytical methods for
measuring concentrations of respirable coal mine dust and respirable
silica dust are both statistically unbiased, <greek-e> has a mean
value of zero and a degree of variability represented by its
standard deviation, denoted by <greek-s><greek-e>. The ratio of
<greek-s><greek-e> to <greek-m> is called the measurement
coefficient of variation (CV) due to sampling and analytical
errors.\1\ The CV relates entirely to variability due to measurement
errors and not at all to variability in actual dust concentrations.
---------------------------------------------------------------------------
\1\ In some publications, this ratio is called the relative
standard deviation (RSD). It is sometimes also denoted by
CV<INF>total</INF>, where ``total'' refers to all sources of
potential sampling and analytical error but does not cover
variability in <greek-m> itself.
---------------------------------------------------------------------------
For respirable coal mine dust, the value of CV used in
calculating critical values was chosen to be consistent with the
value proposed at <greek-m> = 2.0 mg/m\3\ in the Coal Mine
Respirable Dust Standard Noncompliance Determinations Notice, (63 FR
5700, February 3, 1998):
[GRAPHIC] [TIFF OMITTED] TP43AD00.000
The 7-percent term in this formula accounts for uncertainty due to
potential weighing error, and the two 5-percent terms account for
differences between individual cyclones and for variability in the
exact volume of air pumped through the filter during a 480-minute
shift.
For respirable silica dust, the value of CV used in calculating
critical values is:
[GRAPHIC] [TIFF OMITTED] TP43AD00.001
The 5.3-percent term in this formula accounts for imprecision in the
Infrared (Infrared Spectrophotometer or IR) measurement of
crystalline silica mass deposited on the filter, the 4.2-percent
term represents variability in air volume, and the final 5.6-percent
term accounts for uncertainty due to variability between individual
cyclones, given the size distribution of crystalline silica dust
encountered in mining environments (Bartley, November 1999).
Each critical value (c) was calculated to provide a confidence
level of at least 95 percent that the ventilation plan was effective
in preventing dust concentrations from exceeding the verification
limits. Using a confidence coefficient of 1.645, based on the
standard normal probability distribution, knowledge of the CV makes
it possible to calculate a 1-tailed, 95-percent upper confidence
limit (UCL) for <greek-m>, given a single measurement X. The UCL is
X<t-bullet>(1 + 1.645<t-bullet>CV). When X <ls-thn-eq> c, the UCL
for <greek-m> is less than or equal to the verification limit. When
X > c, the UCL for <greek-m> exceeds the verification limit.
For example, suppose X = 1.71 mg/m\3\ respirable dust. Then the
UCL for <greek-m> would be 1.71<t-bullet>(1 + (10% of 1.645)) = 1.99
mg/m\3\, which is less than the verification limit for respirable
coal mine dust. If, however, X = 1.72 mg/m\3\, then the UCL for
<greek-m> would be 1.72<t-bullet>1.1645 mg/m\3\, which slightly
exceeds the verification limit. Similarly, for respirable
crystalline silica dust, the UCL for <greek-m> is 87<t-bullet>(1 +
(9% of 1.645)) = 99.9 <greek-m>g/m\3\ when X = 87 <greek-m>g/m\3\
and slightly above the verification limit of 100 <greek-m>g/m\3\
when X = 88 <greek-m>g/m\3\.
If more than one measurement is available, then the confidence
coefficient changes to reflect multiplication of the tail
probabilities for independent measurement errors. When n
measurements are available, the objective is to calculate a critical
value (c) such that if each of the n measurements is <ls-thn-eq> c,
then the 1-tailed 95-percent UCL for <greek-m> is <ls-thn-eq> the
verification limit. Since the product of the n individual tail
probabilities must equal 0.05, the appropriate 1-tail probability
for each measurement individually is the n\th\ root of 0.05.
For example, if n = 3, then the appropriate 1-tail probability
for each measurement is the cube root of 0.05, or 0.3684. The
standard normal confidence coefficient corresponding to this tail
probability is 0.336. Therefore, when all three measurements have
the same value (X), the UCL is X<t-bullet>(1+0.336<t-bullet>CV).
Substituting the appropriate CV estimate, the UCL is
X<t-bullet>1.0336 for coal mine dust or X<t-bullet>1.0302 for
crystalline silica. Consequently, to obtain the critical value, the
verification limit is first divided by 1.0336 (coal mine dust) or
1.0302 (crystalline silica dust) and then truncated to the desired
number of decimal digits. This yields 1.93 mg/m\3\ for coal mine
dust and 97 <greek-m>g/m\3\ for respirable crystalline silica dust.
The confidence coefficients used to establish critical values by
this method are as follows:
n--Confidence Coefficient
1 1.645
2 0.760
3 0.336
4 0.068
For n > 4, the confidence coefficient is less than 0.068.
It should be noted that although the critical value calculated
for n <gr-thn-eq> 4 is slightly below the verification limit for
both types of dust, for simplicity it was set equal to the
verification limit as a close approximation.
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XII. Regulatory Text
List of Subjects
30 CFR part 70
Coal, Mine safety and health, Underground coal mines, Respirable
dust.
30 CFR part 75
Coal, Mine safety and health, Underground coal mines, Ventilation.
30 CFR part 90
Coal, Mine safety and health.
Dated: June 20, 2000.
J. Davitt McAteer,
Assistant Secretary for Mine Safety and Health.
Accordingly, it is proposed to amend Chapter I of Title 30 of the
Code of Federal Regulations as follows:
PART 70--MANDATORY HEALTH STANDARDS--UNDERGROUND COAL MINES
1. The authority citation for part 70 continues to read as follows:
Authority: 30 U.S.C. 811, 813(h), 957 and 961, unless otherwise
noted.
2. Section 70.2 is revised to read as follows:
Subpart A--General
Sec.
70.2 Definitions.
Subpart A--General
Sec. 70.2 Definitions.
(a) Act means the Federal Mine Safety and Health Act of 1977,
Public Law 91-173, as amended by Public Law 95-164, 30 U.S.C. 801 et.
seq.
(b) Active workings means any place in a coal mine where miners are
normally required to work or travel.
(c) Concentration means an 8-hour MRE equivalent measure of the
amount of respirable dust per unit volume of air. The concentration of
respirable dust is determined in two steps. First, divide the weight of
dust in milligrams collected on the filter of an approved sampling
device by 480 minutes times the sampler flow rate. Second, multiply
that concentration by a constant factor prescribed by the Secretary for
the approved sampling device used. The product is the equivalent
concentration as measured with an MRE instrument.
(d) Critical value means the highest full shift dust concentration
measurement that MSHA will accept in approving a mine ventilation plan
or interim plan.
(e) Designated area (DA) means an area of a mine identified by the
operator under Sec. 75.371(t) of this title and approved by the
District Manager, or identified by the Secretary. Each DA will be
identified by a four-digit identification number assigned by MSHA.
(f) Designated occupation (DO) means the occupation or work
location on a mechanized mining unit that has been determined by
results of respirable dust samples to have the greatest respirable dust
concentration.
(g) District Manager means the manager of the Coal Mine Safety and
Health District in which the mine is located.
(h) Dust control parameters means the engineering or environmental
controls, maintenance procedures, and any other requirements specified
in each ventilation plan that are being used on the mechanized mining
unit and throughout the mine to control the level of respirable coal
mine dust and respirable quartz dust in the work environment.
(i) Engineering or environmental controls means any method to
control the level of respirable coal mine dust and quartz dust in the
work environment by either reducing dust generation or by suppressing,
diluting, capturing or diverting the dust being generated during the
mining process. It does not include powered, air-purifying respirators
(PAPRs) or any other type of personal protection equipment.
(j) Full shift means an entire work shift including travel time but
excluding, for purposes of bimonthly sampling only, any time in excess
of 480 minutes.
[[Page 42178]]
(k) Interim ventilation plan means a ventilation plan for a
longwall operation under which operators are allowed to use PAPRs or
verifiable administrative controls.
(l) Longwall face means a working place in a coal mine where coal
is extracted from the exposed face or seam using the longwall method of
mining.
(m) Longwall mining section means the area of the coal mine
employing longwall mining, from the loading point of the section up to
and including the longwall face. The loading point is also included.
(n) Material produced means coal and/or any other substance
extracted by a mechanized mining unit during any production shift.
(o) Mechanized mining unit (MMU) means a unit of mining equipment
including hand loading equipment used for the production of material;
or a specialized unit which utilizes mining equipment other than
specified in Sec. 70.206 for the production of material. MSHA assigns
each MMU a four digit identification number. The MMU retains the
identification number regardless of where the unit relocates within the
mine. When two sets of mining equipment are provided in a series of
working places and only one production crew is employed at any given
time on either set of mining equipment, the two sets of equipment are
identified as a single MMU. When two or more MMUs are simultaneously
engaged in the production of material within the same working section,
each such MMU is identified separately.
(p) MRE means the Mining Research Establishment of the National
Coal Board, London, England.
(q) MRE instrument means the gravimetric dust sampler with a four
channel horizontal elutriator developed by the Mining Research
Establishment of the National Coal Board, London, England.
(r) MSHA means the Mine Safety and Health Administration of the
Department of Labor.
(s) Powered, air-purifying respirator (PAPR) means a type of loose-
fitting helmet respirator with a visor that uses a blower to force the
ambient air through air-purifying elements to deliver filtered air into
the miner's breathing area.
(t) Production shift means:
(1) With regard to a mechanized mining unit, a shift during which
material is produced, or
(2) With regard to a designated area of a mine, a shift during
which material is produced and routine day-to-day activities are
occurring in the designated area.
(u) Provisional ventilation plan means a ventilation plan which has
been approved by the District Manager pending verification by MSHA of
the effectiveness of the plan's dust control parameters.
(v) Quartz means crystalline silicon dioxide (SiO<INF>2</INF>) as
measured by MSHA's Analytical Method P-7: Infrared Determination of
Quartz in Respirable Coal Mine Dust.
(w) Respirable dust means dust collected with a sampling device
approved by the Secretary and the Secretary of Health and Human
Services in accordance with part 74 (Coal Mine Dust Personal Sampler
Units) of this title. Sampling device approvals issued by the Secretary
of the Interior and Secretary of Health, Education, and Welfare are
continued in effect.
(x) Secretary means the Secretary of Labor or delegate.
(y) Verifiable administrative control means any work practice that
can significantly reduce daily exposure to respirable dust hazards by
altering the way in which work is performed and which:
(1) Can be reviewed to confirm its proper implementation,
(2) Is clearly understood by miners, and
(3) Can be applied consistently over time.
(z) Verification limits means 2.0 mg/m\3\ of respirable coal mine
dust and 100 <greek-m>g/m\3\ of respirable quartz dust (MRE-equivalent
concentrations) measured over a full shift.
(aa) Verification production level (VPL) means the tenth highest
production level recorded in the most recent thirty production shifts.
(bb) Verification sample means a valid sample taken on a full shift
during which the amount of material produced is at or above the VPL and
using only the engineering or environmental controls and other measures
included in the ventilation plan, at levels not exceeding 115% of the
quantities specified in the plan.
3. Subpart B is revised to read as follows:
Subpart B--Dust Standards
70.100 What are the respirable dust standards when quartz is not
present?
70.101 What is the respirable dust standard when quartz is present?
Subpart B--Dust Standards
Authority: 30 U.S.C. 811 and 813(h).
Sec. 70.100 What are the respirable dust standards when quartz is not
present?
When quartz is not present:
(a) Each operator shall continuously maintain the average
concentration of respirable dust in the mine atmosphere during each
shift to which each miner in the active workings of each mine is
exposed at or below 2.0 milligrams of respirable dust per cubic meter
of air as measured with an approved sampling device and in terms of an
equivalent concentration determined in accordance with Sec. 70.2(c).
(b) Each operator shall continuously maintain the average
concentration of respirable dust within 200 feet outby the working
faces of each section in the intake airways at or below 1.0 milligrams
of respirable dust per cubic meter of air as measured with an approved
sampling device and in terms of an equivalent concentration determined
in accordance with Sec. 70.2(c).
Sec. 70.101 What is the respirable dust standard when quartz is
present?
When the respirable dust in the mine atmosphere of the active
workings contains more than 5 percent quartz as determined by samples
taken by the Secretary, the operator shall continuously maintain the
average concentration of respirable dust in the mine atmosphere during
each shift to which each miner in the active workings is exposed at or
below a concentration of respirable dust, expressed in milligrams per
cubic meter of air as measured with an approved sampling device and in
terms of an equivalent concentration determined in accordance with
Sec. 70.2(c), computed by dividing the percent of quartz into the
number 10.
Example: The respirable dust associated with a mechanized mining
unit or a designated area in a mine contains quartz in the amount of
20%. Therefore, the average concentration of respirable dust in the
mine atmosphere associated with that mechanized mining unit or
designated area shall be continuously maintained at or below 0.5
milligrams of respirable dust per cubic meter of air (10/20=0.5 mg/m\3\
).
4. Subpart C is revised to read as follows:
[[Page 42179]]
Subpart C--Verification of Underground Coal Mine Ventilation Plan
Effectiveness; Use of Approved Powered, Air-Purifying Respirators;
Use of Verifiable Administrative Controls; Actions Necessary When
in Violation of Respirable Dust Standard; and Status Change Reports
Verification of Underground Coal Mine Ventilation Plan Effectiveness
70.201 Who must have a verified ventilation plan?
70.202 What is a verified ventilation plan?
70.203 What will trigger the plan verification process?
70.204 When will MSHA conduct verification sampling?
70.205 What must I (the operator) do to comply with this standard?
70.206 Who will MSHA sample and where will MSHA place the sampling
device(s) when conducting verification sampling?
70.207 How many shifts will MSHA sample to verify my ventilation
plan?
70.208 What if 30 shifts of production data are not available to
establish the verification production level (VPL)?
70.209 When will MSHA approve my ventilation plan?
70.210 What must I (the operator) do if a verification sample
exceeds either verification limit?
70.211 What if verification samples continue to exceed either
verification limit even though I (the operator) believe all feasible
engineer and environmental controls are in place?
Use of Approved Powered, Air-Purifying Respirators
70.212 For my longwall operation, what must I (the operator) do in
order to use approved PAPRs to supplement engineering or
environmental controls?
70.213 For my longwall operation, when will MSHA approve my interim
ventilation plan incorporating a PAPR respiratory protection
program?
70.214 For my longwall operation, under what circumstances may I
(the operator) continue to use PAPRs to supplement engineering or
environmental controls?
70.215 What if an MSHA DO sample exceeds the applicable dust
standard, or an MSHA sample for a miner required to wear a PAPR
exceeds twice the applicable dust standard?
Use of Verifiable Administrative Controls
70.216 For my longwall operation, what must I (the operator) do in
order to use verifiable administrative controls to supplement
engineering or environmental controls?
70.217 For my longwall operation, when will MSHA approve my interim
ventilation plan incorporating verifiable administrative controls?
70.218 For my longwall operation with an approved interim
ventilation plan, what must I (the operator) do if an MSHA sample
exceeds the applicable dust standard?
Actions Necessary When in Violation of Respirable Dust Standards
70.219 What must I (the operator) do if I am cited for exceeding
the applicable dust standard?
Information to Be Posted on the Mine Bulletin Board
70.220 What information must I (the operator) post on the mine
bulletin board?
Status Change Reports
70.221 What action must I (the operator) take if the operational
status of my mine, MMU, or DA changes?
Subpart C--Verification of Underground Coal Mine Ventilation Plan
Effectiveness; Use of Approved Powered, Air-Purifying Respirators;
Use of Verifiable Administrative Controls; Actions Necessary When
in Violation of Respirable Dust Standard; and Status Change Reports
Authority: 30 U.S.C. 811, 813(h), and 957.
Verification of Underground Coal Mine Ventilation Plan
Effectiveness
Sec. 70.201 Who must have a verified ventilation plan?
All underground coal mine operators must have a verified
ventilation plan.
Sec. 70.202 What is a verified ventilation plan?
A verified ventilation plan is a plan that has been demonstrated as
effective, at a high level of confidence, in maintaining the
concentration of respirable coal mine dust and quartz dust in each MMU
at or below 2.0 mg/m\3\ and 100 <greek-m>g/m\3\, respectively. This
demonstration is based on MSHA verification samples.
Sec. 70.203 What will trigger the plan verification process?
MSHA will initiate the plan verification process when:
(a) You submit a new ventilation plan under Sec. 75.370 or you
amend a previously approved ventilation plan under Sec. 75.371(f); or
(b) The District Manager requires you to change the ventilation
plan after determining that your dust control parameters no longer
effectively control the concentration of respirable dust in the working
environment of an MMU under the current mining conditions; or
(c) You propose revisions to a previously verified ventilation plan
and the District Manager determines that the proposed revisions may
cause the plan to be inadequate.
Sec. 70.204 When will MSHA conduct verification sampling?
The District Manager will notify you of the schedule for
verification sampling after granting provisional approval of your
ventilation plan. Before you receive provisional approval, however, you
may be required to change your plan if the District Manager determines
that your dust control parameters are inadequate or unsuitable for the
current mining conditions.
Sec. 70.205 What must I (the operator) do to comply with this
standard?
To comply with this standard, at the time the District Manager
notifies you that MSHA will conduct verification sampling you must:
(a) Set your operating conditions so as to mine at or above the VPL
and use only the dust control parameters and other measures listed in
your plan on the date scheduled for verification sampling;
(b) For each MMU to be sampled, make available records of the
amount of material produced each shift during the previous six-month
period as prescribed in Sec. 75.370(h);
(c) Provide the additional information described under
Sec. 75.371(f); and
(d) Notify the District Manager if you cannot meet the conditions
described in paragraph (a) on the scheduled date.
Sec. 70.206 Who will MSHA sample and where will MSHA place the
sampling device(s) when conducting verification sampling?
(a) MSHA will sample the environment of:
(1) The designated occupation (DO); roofbolter operators; longwall
jack setters; and
(2) Any other occupation designated by the District Manager.
(b) Unless otherwise directed by the District Manager, MSHA will
take DO samples by placing the sampling device(s) in the following
locations:
(1) Conventional section using cutting machine--on the cutting
machine operator or on the cutting machine within 36 inches inby the
normal working position;
(2) Conventional section shooting off the solid--on the loading
machine operator or on the loading machine within 36 inches inby the
normal working position;
(3) Continuous mining section other than auger-type--on the
continuous mining machine operator or on the continuous mining machine
within 36 inches inby the normal working position;
(4) Continuous mining machine; auger-type--on the jacksetter who
works nearest the working face on the return air side of the continuous
mining machine or at a location that represents the maximum
concentration of dust to which the miner is exposed;
[[Page 42180]]
(5) Scoop section using cutting machine--on the cutting machine
operator or on the cutting machine within 36 inches inby the normal
working position;
(6) Scoop section shooting off the solid--on the coal drill
operator or on the coal drill within 36 inches inby the normal working
position;
(7) Longwall section--on the miner who works nearest the return air
side of the longwall working face or along the working face on the
return side within 48 inches of the corner;
(8) Hand loading section with a cutting machine--on the cutting
machine operator or on the cutting machine within 36 inches inby the
normal working position;
(9) Hand loading section shooting off the solid--on the hand loader
exposed to the greatest dust concentration or at a location that
represents the maximum concentration of dust to which the miner is
exposed; and
(10) Anthracite mine sections--on the hand loader exposed to the
greatest dust concentration or at a location that represents the
maximum concentration of dust to which the miner is exposed.
Sec. 70.207 How many shifts will MSHA sample to verify my ventilation
plan?
MSHA can approve your ventilation plan based on only one shift of
sampling, provided all the samples taken on that shift meet the
criteria for a verification sample and none of them exceed the critical
values for a single shift specified in Secs. 70.209 and 70.213. We will
sample additional shifts if one verification sample exceeds the
specified critical values, or if any of the samples taken do not meet
the criteria for a verification sample.
Sec. 70.208 What if 30 shifts of production data are not available to
establish the verification production level (VPL)?
If you do not have 30 shifts of production data to establish a VPL,
the VPL will be the minimum production level attained on a shift that
was sampled to verify the plan's effectiveness. This production level
must be incorporated into the ventilation plan that is ultimately
approved by the District Manager.
Sec. 70.209 When will MSHA approve my ventilation plan?
MSHA will approve your ventilation plan when:
(a) None of the verification samples exceed the following critical
values for respirable coal mine dust and quartz dust:
(1) For respirable coal mine dust, the critical value is:
(i) 1.71 mg/m\3\ if samples are collected for only one shift;
(ii) 1.85 mg/m\3\ if samples are collected for two shifts;
(iii)1.93 mg/m\3\ if samples are collected for three shifts; and
(iv) 2.0 mg/m\3\ if samples are collected for four or more shifts.
(2) For respirable quartz dust, the critical value is:
(i) 87 ``<greek-m>g/m\3\ if samples are collected for only one
shift;
(ii) 93 ``<greek-m>g/m\3\ if samples are collected for two shifts;
(iii) 97 ``<greek-m>g/m\3\ if samples are collected for three
shifts; and
(iv) 100 ``<greek-m>g/m\3\ if samples are collected for four or
more shifts.
(b) You adjust your plan, if necessary, to include all the dust
control parameters that were in effect during verification sampling.
Sec. 70.210 What must I (the operator) do if a verification sample
exceeds either verification limit?
If a verification sample exceeds either verification limit, you
must:
(a) Immediately take corrective action to lower the concentration
of respirable dust in the work environment of the affected occupation
or location to a level no greater than the applicable verification
limit;
(b) Make approved respiratory equipment available to affected
miners following the procedures in Sec. 70.300; and
(c) Within 5 days of receiving results of verification sampling,
submit changes in your dust control parameters and any other corrective
actions you implemented to the District Manager for review. The
District Manager will notify you if your ventilation plan is
provisionally approved under Sec. 70.210 (c).
(1) If your ventilation plan is provisionally approved, the
District Manager will notify you when MSHA will start verification
sampling over again, or continue verification sampling.
(2) If your ventilation plan is not provisionally approved, the
District Manager will require you to make additional changes in your
plan parameters. Once you have made all required changes to your plan
parameters, you will receive provisional approval of your ventilation
plan. Then, the District Manager will notify you when MSHA will start
verification sampling over again, or continue verification sampling
from the point at which it stopped.
Sec. 70.211 What if verification samples continue to exceed either
verification limit even though I (the operator) believe all feasible
engineering and environmental controls are in place?
If verification samples continue to exceed the verification limit
and you believe all feasible engineering and environmental controls are
in place, then:
(a) If the ventilation plan being verified is for an MMU that uses
a mining system other than longwall mining, MSHA may suggest additional
controls for you to implement.
(b) If the MMU employs a longwall mining system, MSHA may suggest
additional controls for you to implement; and, you may request in
writing that the Administrator for Coal Mine Safety and Health
determine whether or not you are using all feasible engineering or
environmental controls to reduce concentrations of respirable dust to
as low a level as possible; and
(c) If MSHA determines that you are using all feasible engineering
or environmental on your longwall, based on its assessment of the
suitability of available control measures to your particular MMU, MSHA
will notify you that you may use either powered, air-purifying
respirators (PAPRs) approved under 42 CFR 84, or verifiable
administrative controls on an interim basis to supplement the
engineering or environmental controls you have implemented to achieve
compliance, until additional feasible engineering or environmental
controls become available. If you use these supplements, the DO would
be changed from the 060 to the 044 occupation.
Use of Approved Powered, Air-Purifying Respirators
Sec. 70.212 For my longwall operation, what must I (the operator) do
in order to use approved PAPRs to supplement engineering or
environmental controls?
In order to use PAPRs to supplement engineering or environmental
controls, you must:
(a) Submit a revised ventilation plan to the District Manager
within 5 days of receiving notification allowing you to supplement the
engineering or environmental controls on your longwall for compliance
purposes. Your plan must include feasible engineering or environmental
controls capable of maintaining concentrations of respirable dust in
the environment of:
(1) The DO (Occ 044--longwall operator or the occupation selected
by the District Manager) at or below the verification limits; and
(2) Any miner working downwind of the DO, who is required to wear a
PAPR,
[[Page 42181]]
at or below two times the verification limits.
(b) Incorporate in your plan a respiratory protection program for
the use of PAPRs following the procedures specified in Sec. 72.710.
MSHA's District Manager may require you to make modifications to your
respiratory protection program before granting provisional approval;
(c) Obtain provisional approval of your ventilation plan from the
District Manager;
(d) Have MSHA verify your plan's effectiveness by sampling the
environment of the DO (Occ 044--longwall operator) or other occupation
directed by the District Manager and those miners working downwind of
the DO who are required to wear approved PAPRs on the longwall face
following the verification sampling procedures in Secs. 70.205 and
70.206;
(e) Maintain and monitor compliance with the revised ventilation
plan; and
(f) Continue to look for improvements that you can make and
implement feasible solutions when they become available that would
maintain the environment of the miners required to wear PAPRs at or
below the verification limits.
Sec. 70.213 For my longwall operation, when will MSHA approve my
interim ventilation plan incorporating a PAPR respiratory protection
program?
MSHA will approve your interim ventilation plan when:
(a) None of the verification samples for the DO exceed the critical
values for respirable coal mine dust and quartz dust specified in
Sec. 70.209;
(b) None of the verification samples for the miners working
downwind of the DO, who are required to wear approved PAPRs, exceed the
following critical values for respirable coal mine dust and quartz
dust:
(1) For respirable coal mine dust, the value is:
(i) 3.54 mg/m\3\ if samples are collected for only one shift;
(ii) 3.77 mg/m\3\ if samples are collected for two shifts;
(iii)3.89 mg/m\3\ if samples are collected for three shifts;
(iv) 4.0 mg/m\3\ if samples are collected for four or more shifts.
(2) For respirable quartz dust, the value is:
(i) 174 <greek-m>g/m \3\ if samples are collected for only one
shift;
(ii) 187 <greek-m>g/m \3\ if samples are collected for two shifts;
(iii) 194 <greek-m>g/m \3\ if samples are collected for three
shifts;
(iv) 200 <greek-m>g/m \3\ if samples are collected for four or more
shifts; and
(c) You adjust your plan, if necessary, to include all the dust
control parameters that were in effect during verification sampling.
Sec. 70.214 For my longwall operation, under what circumstances may I
(the operator) continue to use PAPRs to supplement engineering or
environmental controls?
You may continue to use approved PAPRs for compliance purposes
under the following conditions:
(a) You implement and maintain all feasible engineering or
environmental controls on each shift;
(b) You implement and maintain the PAPR respiratory protection
program as approved by the District Manager;
(c) No MSHA DO sample exceeds the applicable dust standards, and no
MSHA sample for any miner working downwind of the DO and required to
wear a PAPR exceeds two times the applicable dust standards; and
(d) You continue to look for improvements that you can make and
implement feasible solutions when they become available that would
maintain the environment of the miners required to wear PAPRs at or
below the verification limits.
Sec. 70.215 What if an MSHA DO sample exceeds the applicable dust
standard, or an MSHA sample for a miner required to wear a PAPR exceeds
twice the applicable dust standard?
If an MSHA DO sample exceeds the dust standard you must:
(a) Promptly review your dust control procedures to determine the
cause of the high dust concentration levels and take appropriate action
to prevent similar occurrences in the future;
(b) Promptly review the continued effectiveness of your approved
PAPR respiratory protection program; and
(c) If necessary, make changes to your dust control parameters and
submit them to the District Manager for review and approval.
Use of Verifiable Administrative Controls
Sec. 70.216 For my longwall operation, what must I (the operator) do
in order to use verifiable administrative controls to supplement
engineering or environmental controls?
In order to use administrative controls for longwall operations you
must:
(a) Submit a revised ventilation plan to the District Manager
within 5 days of receiving notification allowing you to supplement the
engineering or environmental controls on your longwall for compliance
purposes. The plan must include the feasible engineering or
environmental controls being used to reduce the concentrations of
respirable dust on your longwall to as low a level as possible, the
verifiable administrative controls to be implemented on the MMU, and a
method for ensuring that the administrative controls are complied with
at all times;
(b) Obtain provisional approval of your ventilation plan from the
District Manager;
(c) Have MSHA verify your plan's effectiveness by sampling all
miners working along the longwall face, including the DO (Occ 044--
longwall operator) or other occupation designated by the District
Manager;
(d) Maintain and monitor compliance with the revised ventilation
plan; and
(e) Continue to look for improvements that you can make and
implement feasible solutions when they become available that would
maintain the environment of the miners required to work downwind of the
DO and whose exposure is being controlled by administrative controls at
or below the verification limits.
Sec. 70.217 For my longwall operation, when will MSHA approve my
interim ventilation plan incorporating verifiable administrative
controls?
MSHA will approve your interim ventilation plan and use of
administrative controls on your longwall when:
(a) None of the verification samples exceed the critical values for
respirable coal mine dust and quartz dust specified in Sec. 70.209; and
(b) Adjust your plan if necessary, to include all the dust control
parameters that were in effect during verification sampling.
Sec. 70.218 For my longwall operation with an approved interim
ventilation plan, what must I (the operator) do if an MSHA sample
exceeds the applicable dust standard?
If an MSHA sample exceeds the dust standard you must:
(a) Promptly review your dust control procedures to determine the
cause of the excessive dust concentration(s) and take appropriate
action to prevent similar occurrences in the future;
(b) Promptly review the continued effectiveness of the
administrative controls in use; and
(c) If necessary, make changes to your dust control parameters and
submit them to the District Manager for review and approval.
[[Page 42182]]
Actions Necessary When in Violation of Respirable Dust Standards
Sec. 70.219 What must I (the operator) do if I am cited for exceeding
the applicable dust standard?
If you are cited for exceeding the dust standard, you must:
(a) Promptly review your dust control procedures to determine the
cause of the excessive dust concentration(s); and
(b) Take corrective action to lower the concentration of respirable
dust to comply with the applicable standard and notify the District
Manager within 24 hours after implementing the corrective action(s).
MSHA will then sample to determine the effectiveness of your abatement
actions or require reverification of your ventilation plan under
proposed Sec. 70.203. If MSHA samples demonstrate:
(1) Compliance--you must incorporate these corrective actions in
your mine ventilation plan. MSHA may re-verify your ventilation plan
after determining that your dust control parameters originally approved
may be ineffective in controlling the concentrations of respirable dust
in the working environment of the MMU under the current mining
conditions.
(2) Noncompliance--the District Manager may revoke approval of your
mine ventilation plan.
Information to Be Posted on the Mine Bulletin Board
Sec. 70.220 What information must I (the operator) post on the mine
bulletin board?
You must post the following information on the mine bulletin board:
(a) All MSHA sample results;
(b) For each MMU, the engineering and environmental controls and
other practices in effect on each shift of the verification process,
along with the associated values of the dust control parameters
measured;
(c) All written notifications from the District Manager regarding
any aspect of the plan verification process.
(d) You may remove the posted verification results after the
District Manager approves the plan. You must post the results of MSHA
respirable dust compliance samples upon receipt for 31 days.
Status Change Reports
Sec. 70.221 What action must I (the operator) take if the operational
status of my mine, MMU, or DA changes?
(a) You must report the change in operational status of the mine,
MMU, or DA to the MSHA District Office or to any other MSHA office
designated by the District Manager. You must report status changes in
writing within 3 working days after the status change has occurred.
(b) Each specific operational status is defined as follows:
(1) Underground mine:
(i) Producing--has at least one mechanized mining unit producing
material.
(ii) Nonproducing--no material is being produced.
(iii) Abandoned--the work of all miners has been terminated and
production activity has ceased.
(2) Mechanized Mining Unit:
(i) Producing--producing material from a working section.
(ii) Nonproducing--temporarily ceased production of material.
(iii) Abandoned--permanently ceased production of material.
(3) Designated Area:
(i) Producing--activity is occurring.
(ii) Nonproducing--activity has ceased.
(iii) Abandoned--the dust generating source has been withdrawn and
activity has ceased.
PART 75--[AMENDED]
6. The authority citation for part 75 continues to read as follows:
Authority: 30 U.S.C. 811.
7. Paragraph (h) of Sec. 75.370 of Subpart D is added to read as
follows:
Sec. 75.370 Mine ventilation plan; submission and approval.
* * * * *
(h) The operator must record the amount of material produced by
each MMU during each production shift, retain the records for six
months, and make the records available to authorized representatives of
the Secretary and the miners' representative.
8. Section 75.371 of Subpart D is amended by revising paragraphs
(f) and (t) to read as follows:
Sec. 75.371 Mine ventilation plan; contents.
* * * * *
(f) Section and face ventilation systems used, including drawings
illustrating how each system is used; and a description of each
different dust suppression system used on equipment on working
sections, including any specific work practices used to minimize the
dust exposure of individual miners, along with information on the
location of the roof bolter(s) during the mining cycle for each
continuous miner section, and the cut sequence for each longwall mining
section. For plans required to be verified pursuant to Sec. 70.201, the
length of each normal production shift, the verification production
level (VPL) as defined in Sec. 70.2, and additional provisions for the
use of powered, air purifying respirators (PAPRs) or verifiable
administrative controls required under Sec. 70.212-215 and Sec. 70.216-
218, respectively, must be included for each working section.
* * * * *
(t) The location of each ``designated area,'' and the respirable
dust measures used at the dust generating sources for these locations.
PART 90--[Amended]
9. The authority citation for part 90 continues to read as follows:
Authority: 30 U.S.C. 811, 813(h).
10. Subpart A is revised to read as follows:
Sec.
90.1 Scope.
90.2 Definitions.
90.3 Part 90 option; notice of eligibility; exercise of option.
Sec. 90.1 Scope.
This part 90 establishes the option of miners who are employed at
underground coal mines or at surface work areas of underground coal
mines and who have evidence of the development of pneumoconiosis to
work in an area of a mine where the average concentration of respirable
dust in the mine atmosphere during each shift is continuously
maintained at or below 1.0 milligrams per cubic meter of air. The rule
sets forth procedures for miners to exercise this option, and
establishes the right of miners to retain their regular rate of pay and
receive wage increases. The rule also sets forth the operator's
obligations. This part 90 is promulgated pursuant to section 101 of the
Act and supercedes section 203(b) of the Act.
Sec. 90.2 Definitions.
(a) Act means the Federal Mine Safety and Health Act of 1977,
Public Law 91-173, as amended by Public Law 95-164, 30 U.S.C. 801 et
seq.
(b) Active workings means any place in a coal mine where miners are
normally required to work or travel.
(c) Concentration means an 8-hour MRE equivalent measure of the
amount respirable dust per unit volume of air. The concentration of
respirable dust is determined in two steps. First, divide the weight of
dust in milligrams collected on the filter of an approved sampling
device by 480 minutes times the sampler flow rate. Second, multiply
that concentration by a constant factor prescribed by the Secretary for
the approved sampling device used. The product is the equivalent
concentration as measured with an MRE instrument.
[[Page 42183]]
(d) District Manager means the manager of the Coal Mine Safety and
Health District in which the mine is located.
(e) Mechanized mining unit (MMU) means:
(1) A unit of mining equipment including hand loading equipment
used for the production of material; or
(2) A specialized unit which utilizes mining equipment other than
specified in Sec. 70.206(c). MSHA assigns each MMU a four digit
identification number. The MMU retains the identification number
regardless of where the unit relocates within the mine. When two sets
of mining equipment are provided in a series of working places and only
one production crew is employed at any given time on either set of
mining equipment, the two sets of equipment are be identified as a
single MMU. When two or more MMUs are simultaneously engaged in the
production of material within the same working section, each such MMU
is identified separately.
(f) MRE means the Mining Research Establishment, of the National
Coal Board, London, England.
(g) MRE instrument means the gravimetric dust sampler with a four
channel horizontal elutriator developed by the Mining Research
Establishment of the National Coal Board, London, England.
(h) MSHA means the Mine Safety and Health Administration of the
Department of Labor.
(i) Normal work duties means duties which the part 90 miner
performs on a routine day-to-day basis in his or her job classification
at a mine.
(j) Part 90 miner means a miner employed at an underground coal
mine or at a surface work area of an underground coal mine who has
exercised the option under the old section 203(b) program (36 FR 20601,
October 27, 1971), or under Sec. 90.3 (part 90 option; notice of
eligibility; exercise of option) of this part to work in an area of a
mine where the average concentration of respirable dust in the mine
atmosphere during each shift to which that miner is exposed is
continuously maintained at or below 1.0 milligrams per cubic meter of
air, and who has not waived these rights.
(k) Quartz means crystalline silicon dioxide (SiO<INF>2</INF>) as
measured by MSHA's Analytical Method P-7: Infrared Determination of
Quartz in Respirable Coal Mine Dust.
(l) Respirable dust means dust collected with a sampling device
approved by the Secretary and the Secretary of Health and Human
Services in accordance with part 74 (Coal Mine Dust Personal Sampler
Units) of this title. Sampling device approvals issued by the Secretary
of the Interior and Secretary of Health, Education, and Welfare are
continued in effect.
(m) Secretary means the Secretary of Labor or a designee.
(n) Secretary of Health and Human Services means Secretary of
Health and Human Services or Secretary of Health, Education, and
Welfare.
(o) Surface work area of an underground coal mine means the surface
areas of land and all structures, facilities, machinery, tools,
equipment, shafts, slopes, excavations, and other property, real or
personal, placed upon or above the surface of such land by any person,
used in, or to be used in, or resulting from, the work of extracting
bituminous coal, lignite, or anthracite from its natural deposits
underground by any means or method, and the work of preparing coal so
extracted, and includes custom coal preparation facilities.
(p) Transfer means any change in the work assignment of a part 90
miner by the operator and includes:
(1) Any change in occupation code of a part 90 miner;
(2) Any movement of a part 90 miner to or from a mechanized mining
unit; or
(3) Any assignment of a part 90 miner to the same occupation in a
different location at a mine.
(q) Underground coal mine means an area of land and all structures,
facilities, machinery, tools, equipment, shafts, slopes, tunnels,
excavations, and other property, real or personal, placed upon, under,
or above the surface of such land by any person, used in, or to be used
in, or resulting from the work of extracting in such area bituminous
coal, lignite, or anthracite from its natural deposits in the earth by
any means or method, and the work of preparing the coal so extracted.
Sec. 90.3 Part 90 option; notice of eligibility; exercise of option.
(a) Any miner employed at an underground coal mine or at a surface
work area of an underground coal mine who, in the judgment of the
Secretary of Health and Human Services, has evidence of the development
of pneumoconiosis based on a chest X-ray, read and classified in the
manner prescribed by the Secretary of Health and Human Services, or
based on other medical examinations shall be afforded the option to
work in an area of a mine where the average concentration of respirable
dust in the mine atmosphere during each shift to which that miner is
exposed is continuously maintained at or below 1.0 milligrams per cubic
meter of air. Each of these miners shall be notified in writing of
eligibility to exercise the option.
(b) Any miner who is a section 203(b) miner on January 31, 1981,
shall be a part 90 miner on February 1, 1981, entitled to full rights
under this part to retention of pay rate, future actual wage increases,
and future work assignment, shift and respirable dust protection.
(c) Any part 90 miner who is transferred to a position at the same
or another coal mine shall remain a part 90 miner entitled to full
rights under this part at the new work assignment.
(d) The option to work in a low dust area of the mine may be
exercised for the first time by any miner employed at an underground
coal mine or at a surface work area of an underground coal mine who was
eligible for the option under the old section 203(b) program (36 FR
20601, October 27, 1971), or is eligible for the option under this part
by signing and dating the Exercise of Option Form and mailing the form
to the Chief, Division of Health, Coal Mine Safety and Health, MSHA,
4015 Wilson Boulevard, Arlington, Virginia 22203.
(e) The option to work in a low dust area of the mine may be re-
exercised by any miner employed at an underground coal mine or at a
surface work area of an underground coal mine who exercised the option
under the old section 203(b).
12. Subpart B is revised to read as follows:
Subpart B--Dust Standards, Rights of Part 90 Miners
Sec.
90.100 Respirable dust standard.
90.101 Respirable dust standard when quartz is present.
90.102 Transfer; notice.
90.103 Compensation.
90.104 Waiver of rights; re-exercise of option.
Subpart B--Dust Standards, Rights of Part 90 Miners
Sec. 90.100 Respirable dust standard.
After the twentieth calendar day following receipt of notification
from MSHA that a part 90 miner is employed at the mine, the operator
shall continuously maintain the average concentration of respirable
dust in the mine atmosphere during each shift to which the part 90
miner in the active workings of the mine is exposed at or below 1.0
milligrams per cubic meter of air.
Sec. 90.101 Respirable dust standard when quartz is present.
When the respirable dust in the mine atmosphere of the active
workings to
[[Page 42184]]
which a part 90 miner is exposed contains more than 5 percent quartz,
the operator shall continuously maintain the average concentration of
respirable dust in the mine atmosphere during each shift to which a
part 90 miner is exposed at or below a concentration of respirable dust
computed by dividing the percent of quartz into the number 10. The
application of the formula shall not result in a respirable dust
standard in excess of 1.0 milligrams per cubic meter of air.
Example: The respirable dust associated with a part 90 miner
contains quartz in the amount of 20%. Therefore, the average
concentration of respirable dust in the mine atmosphere associated
with that part 90 miner shall be continuously maintained at or below
0.5 milligrams of respirable dust per cubic meter of air (10/20=0.5
mg/m\3\).
Sec. 90.102 Transfer; notice.
(a) Whenever a part 90 miner is transferred in order to meet the
respirable dust standard in Sec. 90.100 (Respirable dust standard) or
Sec. 90.101 (Respirable dust standard when quartz is present), the
operator shall transfer the miner to an existing position at the same
coal mine on the same shift or shift rotation on which the miner was
employed immediately before the transfer. The operator may transfer a
part 90 miner to a different coal mine, a newly-created position or a
position on a different shift or shift rotation if the miner agrees in
writing to the transfer.
(b) On or before the twentieth calendar day following receipt of
notification from MSHA that a part 90 miner is employed at the mine,
the operator shall give the District Manager written notice of the
occupation and, if applicable, the mechanized mining unit to which the
part 90 miner will be assigned on the twenty-first calendar day
following receipt of the notification from MSHA.
(c) After the twentieth calendar day following receipt of
notification from MSHA that a part 90 miner is employed at the mine,
the operator shall give the District Manager written notice before any
transfer of a part 90 miner. This notice shall include the scheduled
date of the transfer.
Sec. 90.103 Compensation.
(a) The operator shall compensate each part 90 miner at not less
than the regular rate of pay received by that miner immediately before
exercising the option under Sec. 90.3 (part 90 option; notice of
eligibility; exercise of option).
(b) Whenever a part 90 miner is transferred, the operator shall
compensate the miner at not less than the regular rate of pay received
by that miner immediately before the transfer.
(c) The operator shall compensate each miner who is a section
203(b) miner on January 31, 1981, at not less than the regular rate of
pay that the miner is required to receive under section 203(b) of the
Act immediately before the effective date of this part.
(d) In addition to the compensation required to be paid under
paragraphs (a), (b) and (c) of this section, the operator shall pay
each part 90 miner the actual wage increases that accrue to the
classification to which the miner is assigned.
(e) If a miner is temporarily employed in an occupation other than
his or her regular work classification for two months or more before
exercising the option under Sec. 90.3 (part 90 option; notice of
eligibility; exercise of option), the miner's regular rate of pay for
purposes of paragraph (a) and (b) of this section is the higher of the
temporary or regular rates of pay. If the temporary assignment is for
less than two months, the operator may pay the part 90 miner at his or
her regular work classification rate regardless of the temporary wage
rate.
(f) If a part 90 miner is transferred, and the Secretary
subsequently notifies the miner that notice of the miner's eligibility
to exercise the part 90 option was incorrect, the operator shall retain
the affected miner in the current position to which the miner is
assigned and continue to pay the affected miner the applicable rate of
pay provided in paragraphs (a), (b), (c) and (d) of this section,
until:
(1) The affected miner and operator agree in writing to a position
with pay at not less than the regular rate of pay for that occupation;
or
(2) A position is available at the same coal mine in both the same
occupation and on the same shift on which the miner was employed
immediately before exercising the option under Sec. 90.3 (Part 90
option; notice of eligibility; exercise of option) or under the old
section 203(b) program (36 FR 20601, October 27, 1971).
(i) When such a position is available, the operator shall offer the
available position in writing to the affected miner with pay at not
less than the regular rate of pay for that occupation.
(ii) If the affected miner accepts the available position in
writing, the operator shall implement the miner's reassignment upon
notice of the miner's acceptance. If the miner does not accept the
available position in writing, the miner may be reassigned and
protections under Part 90 shall not apply. Failure by the miner to act
on the written offer of the available position within 15 days after
notice of the offer is received from the operator shall operate as an
election not to accept the available position.
Sec. 90.104 Waiver of rights; re-exercise of option.
(a) A part 90 miner may waive his or her rights and be removed from
MSHA's active list of miners who have rights under part 90 by:
(1) Giving written notification to the Chief, Division of Health,
Coal Mine Safety and Health, MSHA, that the miner waives all rights
under this part;
(2) Applying for and accepting a position in an area of a mine
which the miner knows has an average respirable dust concentration
exceeding 1.0 milligrams per cubic meter of air or the respirable dust
standard established by Sec. 90.101 (Respirable dust standard when
quartz is present); or
(3) Refusing to accept another position offered by the operator at
the same coal mine that meets the requirements of Secs. 90.100, 90.101
and 90.102(a) after MSHA dust sampling shows that the average
respirable dust concentration in his or her present position exceeds
1.0 milligrams per cubic meter of air or the respirable dust standard
established by Sec. 90.101 (Respirable dust standard when quartz is
present).
(b) If rights under part 90 are waived, the miner gives up all
rights under part 90 until the miner re-exercises the option in
accordance with Sec. 90.3(e) (part 90 option; notice of eligibility;
exercise of option).
(c) If rights under part 90 are waived, the miner may re-exercise
the option under this part in accordance with Sec. 90.3(e) (part 90
option; notice of eligibility; exercise of option) at any time.
13. Subpart C is revised to read as follows:
90.201 MSHA respirable dust sample reports; operator status change
reporting requirement.
90.202 Operator status change reports.
Sec. 90.201 MSHA Respirable dust sample reports; Operator status
change reporting requirement.
(a) The Secretary shall provide the operator with a report of the
following data on the MSHA respirable dust samples as soon as
practicable:
(1) The mine identification number;
(2) The mechanized mining unit, if any, within the mine from which
the samples were taken;
(3) The concentration of respirable dust, expressed in milligrams
per cubic meter of air, for each valid sample;
(4) The average concentration of respirable dust, expressed in
milligrams
[[Page 42185]]
per cubic meter of air, for all valid samples;
(5) The occupation code;
(6) The reason for voiding any samples; and,
(7) The Social Security Number of the part 90 miner.
(b) Upon receipt, the operator shall provide a copy of this report
to the part 90 miner. The operator shall not post the original or a
copy of this report on the mine bulletin board.
Sec. 90.202 Operator status change reports.
If there is a change in the status of a part 90 miner (such as
entering a terminated, injured or ill status, or returning to work),
the operator must report the change in the status of the part 90 miner
to the MSHA District Office or to any other MSHA office designated by
the District Manager. Status changes shall be reported in writing
within 3 working days after the status change has occurred.
[FR Doc. 00-16149 Filed 7-6-00; 8:45 am]
BILLING CODE 4510-43-P
