Citing danger to the nation’s coal miners, the U.S. Mine Safety and Health Administration (MSHA) has published an emergency temporary standard (ETS) that revises the existing federal standard on maintenance of incombustible content of rock dust. The ETS was announced September 21, 2010, after the agency reviewed accident investigation reports of mine explosions in intake air courses that involved coal dust and a recent National Institute for Occupational Safety and Health report titled “Recommendations for a New Rock Dusting Standard to Prevent Coal Dust Explosions in Intake Airways.” In addition to the ETS, MSHA is also issuing a program information bulletin that provides guidance on the new standard.

The ETS revises the existing standard by requiring mine operators to increase the total incombustible content of the combined coal dust, rock dust and other dust from 65 to 80 percent in all accessible areas of underground bituminous mines and an additional 0.4 percent for each 0.1 percent of methane where the gas is present in any ventilating current. Although the ETS is effective September 23, 2010, mine operators have until October 7 to comply for newly mined areas and until November 22 for all other areas. The agency cites the Federal Mine Safety and Health Act of 1977, as amended, for its authority to issue the ETS.