30 C.F.R. § 62.120
Action level
If during any work shift a miner's noise exposure equals or exceeds the action level the mine operator must enroll the miner in a hearing conservation program that complies with § 62.150 of this part.
If during any work shift a miner's noise exposure equals or exceeds the action level the mine operator must enroll the miner in a hearing conservation program that complies with § 62.150 of this part.