Pennsylvania Statutes Title 52 P.S. Mines and Mining § 690-267. Checking systems

Each bituminous coal mine shall have a check-in and check-out system that will provide positive identification of every individual underground. An accurate record of the individuals in the mine, which shall consist of a written record, a check board, a time clock record or another approved method, shall be kept on the surface in a place that will not be affected in the event of an emergency. The record shall bear a number or name identical to the identification check carried by or fastened to the belt of all individuals going underground.