§864 Combustible Materials and Rock Dusting

Summary

Keep active underground work areas and electrical equipment free of coal dust, loose coal, and other things that can burn. If mining makes too much dust, miners must use water, water with a wetting agent, or another equally effective method approved by the Secretary or an authorized person to control it. In places within 40 feet of the working face, water or approved methods must be applied to the ribs, roof, and floor to cut down dust spread and reduce explosion risk. All underground areas must be covered with rock dust up to 40 feet of working faces (and in crosscuts under 40 feet), unless the dust is too wet, already has enough nonburnable material, the area is unsafe or inaccessible, or an authorized person allows an exception that won’t create a hazard. Rock dust must be applied to roof, floor, and sides so the combined incombustible content is at least 65% (80% in return aircourses). If methane is in the ventilating air, raise the 65% requirement by 1.0% for each 0.1% methane and the 80% requirement by 0.4% for each 0.1% methane. The rules about water methods and rock dusting do not apply to underground anthracite mines.