30 CFR 57.11058 - Check-in, check-out system.
Each operator of an underground mine shall establish a check-in and check-out system which shall provide an accurate record of persons in the mine. These records shall be kept on the surface in a place chosen to minimize the danger of destruction by fire or other hazards. Every person underground shall carry a positive means of being identified.
Title 30 published on 2013-07-01
no entries appear in the Federal Register after this date.