CFR › Title 30 › Part 77 › §77.190930 CFR §77.1909Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗Copy linkExcept as provided in § 77.1909-1, only permissible explosives and permissible shot-firing units shall be used in sinking shafts and slopes.