Code of Federal Regulations Title 43. Public Lands:  Interior § 43.3594.4 Development on leased lands through adjoining mines as part of a mining unit

(a) The only connections between the mine on lands privately owned or controlled and the mine on leased lands shall be the main haulageways, the ventilationways and the escapeways. Substantial concrete frames and fireproof doors that can be closed in an emergency and opened from either side shall be installed in each such connection. Other connections through the boundary pillars shall not be made until both mines are about to be exhausted and abandoned. The authorized officer may waive any of the requirements of this paragraph when it is determined such waiver will not conflict with the regulations in 30 CFR part 57 and will promote maximum recovery of the ore.

(b) Free access for inspection of said connecting mine on lands privately owned or controlled shall be given at any reasonable time to the authorized officer.

(c) If an operator/lessee is operating on a lease through a mine on lands privately owned or controlled does not maintain the mine access in accordance with the safety regulations, operations on the leased lands may be stopped by order of the authorized officer.