(a)
Refuge alternatives shall be provided with a communications system that consists of—
(1)
A two-way communication facility that is a part of the mine communication system, which can be used from inside the refuge alternative; and
(2)
An additional communication system and other requirements as defined in the communications portion of the operator's approved Emergency Response Plan.
Code of Federal Regulations
[73 FR 80700, Dec. 31, 2008]