Maintenance of Incombustible Content of Rock Dust in Underground Coal Mines

The Mine Safety and Health Administration (MSHA) is issuing 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 has concluded, from investigations of mine explosions and other reports, that immediate action is necessary to protect miners. Accumulations of coal dust can ignite, resulting in an explosion, or after an explosion, they can intensify flame propagation, increasing the severity of explosions. 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 coal 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 protections for miners by reducing the potential for a coal mine explosion and reducing the severity of explosions should they occur.