Empty conveyances shall be operated at least one round trip before hoisting persons after any repairs.
30 C.F.R. §77.1405
Sec. 101, Federal Mine Safety and Health Act of 1977, Pub. L. 91-173 as amended by Pub. L. 95-164 , 91 Stat. 1291 (30 U.S.C. 811 )