30 CFR §75.1600
Verified against eCFR.gov as of June 20, 2026View official text on eCFR.gov ↗
Telephone service or equivalent two-way communication facilities, approved by the Secretary or his authorized representative, shall be provided between the surface and each landing of main shafts and slopes and between the surface and each working section of any coal mine that is more than 100 feet from a portal.