§873 Blasting and explosives

Summary

Black blasting powder cannot be stored or used underground, and mudcaps (adobes) or other open, unconfined shots must not be fired underground. Explosives and detonators must be kept apart until right before a blast. In underground anthracite mines, open shots like mudcaps can be used only in narrow cases: to start a battery when there is no methane or fire danger and no other way to start it, or to remove loose coal in pitching veins when other ways are too dangerous. A methane test must be done just before those shots, and if methane is 1.0 volume percent or more the shot must wait until it falls below 1.0 volume percent. Only approved explosives, proper-strength electric detonators, and approved blasting devices may be used underground, with noncombustible stemming materials. The agency can allow more than 20 shots or nonapproved explosives for sinking shafts or slopes from the surface in rock under safety controls. Compressed-air blasting is allowed. People must carry explosives and detonators in closed, nonconductive containers in good condition. Transport must use special closed containers on locomotives, belts, shuttle cars, or other designed equipment. Underground supply boxes must be sturdy, have no exposed metal inside, be dry and rock-dusted, and sit at least 25 feet from roadways and power wires (or be placed in rock niches in pitching beds). In work areas, explosives and detonators must be in separate closed containers, out of the blast line, at least 50 feet from the working face and 15 feet from pipelines, power lines, rails, or conveyors (5 feet if stored in rib niches), and the two types must be kept at least 5 feet apart.