Except as provided in § 77.1909-1 , only permissible explosives and permissible shot-firing units shall be used in sinking shafts and slopes.
30 C.F.R. §77.1909
Except as provided in § 77.1909-1 , only permissible explosives and permissible shot-firing units shall be used in sinking shafts and slopes.
30 C.F.R. §77.1909