Self-contained breathing apparatus of a duration to allow for escape from the mine and sufficient in number to equip all persons underground shall be strategically located throughout the mine. Such apparatus shall be approved by MSHA and NIOSH under 42 CFR part 84 and shall be maintained in accordance with manufacturers' specifications. This standard does not apply to double entry mining systems where crosscut intervals do not exceed 250 feet. [52 FR, 24941, July 1, 1987, as amended at 60 FR 30401, June 8, 1995]
Underground Retorts