Noise Exposure Levels

To prevent hearing loss in miners, MSHA has established various caps on noise exposure levels at mine sites. These caps are important because they help miners and operators recognize acceptable levels of noise exposure and determine what actions to take in the event of hazardous noise exposure:

• The action level is a sound level of 85 dBA within an eight-hour period.
• The permissible exposure level (PEL) is a sound level of 90 dBA within an eight-hour period.
• The dual hearing protection level is a sound level of 105 dBA within an eight-hour period.

According to 30 CFR 62.120 and 62.130, any miner whose noise exposure equals or exceeds the action level or permissible exposure level must be enrolled in a hearing conservation program (HCP).

If a miner's noise exposure exceeds the dual hearing protection level during any work shift, 30 CFR 62.140 requires employers to provide and ensure the concurrent use of both plug-type and muff-type hearing protectors, in addition to the actions required for noise exposures that exceed the PEL.

Miners should never be exposed to noise levels exceeding 115 dBA, even with hearing protection devices in place.

To learn more about MSHA Part 48 training requirements visit our MSHA Part 48 Subpart B Surface Mining Online Training web page.