Mining operations face noise-related regulatory requirements from the Mine Safety and Health Administration (MSHA) rather than OSHA for most activities. MSHA’s noise standard — 30 CFR Part 62 — has similarities to OSHA 29 CFR 1910.95 but differs in key provisions. Mining employers, contractors at mine sites, and service providers operating in MSHA-regulated environments need to understand which standard applies to their workers and how the requirements differ. According to CDC/NIOSH, mining workers have among the highest rates of occupational NIHL of any sector, with surface and underground mining both generating significant noise exposure from drilling, blasting, crushing, and hauling.
MSHA vs. OSHA: The Key Differences
| Requirement | MSHA 30 CFR Part 62 | OSHA 29 CFR 1910.95 |
|---|---|---|
| Action level (TWA) | 90 dBA | 85 dBA |
| Permissible Exposure Limit | 90 dBA | 90 dBA |
| Exchange rate | 5 dB | 5 dB |
| Baseline audiogram timing | Within 12 months of first exposure | Within 6 months (or 12 months with mobile van) |
| Annual audiogram requirement | Yes, for miners at or above action level | Yes, for workers at or above action level |
| Professional review | Physician or audiologist required | Physician or audiologist required |
| Hearing protector requirement | Required when exposure above PEL | Required when worker at action level and not enrolled in HCP |
MSHA’s action level of 90 dBA TWA is 5 dB higher than OSHA’s 85 dBA. This means miners can be exposed at 85–89 dBA TWA without triggering MSHA’s mandatory audiometric testing and hearing protector requirements. At these levels, NIOSH considers workers at significant NIHL risk over a career. Mining companies that align their programs to NIOSH criteria (85 dBA TWA) rather than just MSHA minimums provide meaningfully better worker protection and generate stronger WC defense records.
Contractor Jurisdiction at Mine Sites
Contract employees who work regularly at MSHA-regulated mine sites are typically covered by MSHA jurisdiction during their mine site work, not OSHA. This includes maintenance contractors, equipment operators, delivery personnel with regular site access, and service providers. Contractors whose employees work at both mine sites and non-mine facilities may have dual compliance obligations and should confirm jurisdictional coverage for each work context.
Whether your operation is MSHA or OSHA regulated, designing the hearing conservation program to NIOSH’s REL criteria (85 dBA TWA, 3 dB exchange rate) produces better worker protection outcomes and stronger documentation for WC defense. A program designed to NIOSH criteria will always meet both MSHA and OSHA minimum requirements, since NIOSH is more protective.
Frequently Asked Questions
ANSI-Compliant Audiometric Testing for MSHA and OSHA Programs
Soundtrace automated audiometric testing meets ANSI S3.6 and S3.1-1999 standards required by both MSHA 30 CFR Part 62 and OSHA 29 CFR 1910.95 — with licensed audiologist Professional Supervisor review of all results.
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