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 under the applicable requirements of 30 CFR part 11, 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.
Underground Retorts
053-3 Wyo. Code R. § 57.22315