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United States Department of Labor


RIN: 1219-AB76

Publication ID: Fall 2010

Title: Maintenance of Incombustible Content of Rock Dust in Underground Coal Mines

Abstract: The Mine Safety and Health Administration (MSHA) issued an emergency temporary standard (ETS) under section 101(b) of the Federal Mine Safety and Health Act of 1977 in response to the grave danger that miners in underground bituminous coal mines face when accumulations of coal dust are not made inert. MSHA concluded from investigations of mine explosions and other reports that immediate action was necessary to protect miners. Accumulations of coal dust can ignite, resulting in an explosion, or after an explosion, it can propagate, increasing the severity of the explosion. The ETS requires mine operators to increase the incombustible content of combined coal dust, rock dust, and other dust to at least 80 percent in underground areas of bituminous mines. The ETS further requires that the incombustible content of such combined dust be raised 0.4 percent for each 0.1 percent of methane present. The ETS strengthens the protection for miners by reducing the potential for a coal mine explosion.

Agency: Department of Labor(DOL)

Priority: Other Significant

RIN Status: First time published in the Unified Agenda

Agenda Stage of Rulemaking: Proposed Rule Stage

Major: No

Unfunded Mandates: No

CFR Citation: 30 CFR sec 75.403 (To search for a specific CFR, visit the Code of Federal Regulations.)

Legal Authority: 30 USC 811, 864

Legal Deadline: None

Statement of Need: MSHA determined that a revised standard for "Maintenance of Incombustible Content of Rock Dust" is necessary to immediately protect underground coal miners from hazards of coal dust explosions. This determination is based on: (1) MSHA's accident investigation reports of mine explosions in intake air courses that involved coal dust (Dubaniewicz 2009); (2) the National Institute for Occupational Safety and Health's Report of Investigations 9679 (Cashdollar et al. 2010), "Recommendations for a New Rock Dusting Standard to Prevent Coal Dust Explosions in Intake Airways"; and (3) MSHA's experience and data.

Summary of the Legal Basis: Promulgation of this standard is authorized by section 101(b) of the Federal Mine Safety and Health Act of 1977.

Alternatives: MSHA will consider revisions to the ETS, based on public comments received during the rulemaking process.

Anticipated Costs and Benefits: MSHA estimates that the ETS would result in approximately $22.0 million in yearly costs for the underground bituminous coal mining industry. The ETS provides additional safety protection for miners in underground bituminous coal mines from the explosion hazard of coal and other dusts. MSHA estimates that, on average, the ETS would prevent approximately 1.5 deaths every year and would prevent one additional injury about every 4 years.

Risks: Based on NIOSH's data and recommendations, and MSHA's data and experience, the Secretary determined that miners are exposed to grave danger in areas of underground bituminous coal mines that are not properly and sufficiently rock dusted in accordance with the requirements in this ETS.




FR Cite

Emergency Temporary Standard


75 FR 57849













Comment Period End



Final Action



Regulatory Flexibility Analysis Required: No

Government Levels Affected: None

Small Entities Affected: No

Federalism: No

Included in the Regulatory Plan: Yes

RIN Information URL:

Public Comment URL:

RIN Data Printed in the FR: No

Agency Contact:
Patricia W. Silvey
Director, Office of Standards, Regulations, and Variances
Department of Labor
Mine Safety and Health Administration
Room 631, 1100 Wilson Boulevard, Room 2350,
Arlington, VA 22209-3939
Phone:202 693-9440
Fax:202 693-9441