Part 4. Mining Industries of California Labor Code >> Division 5. >> Part 4.
In all mines operated in the State where a depth of more than
five hundred feet underground has been reached, a telephone system
shall be established, equipped and maintained by the owners or
lessees of the mine with stations at each working level below the
depth aforesaid, communicating with a station on the surface of the
The failure or refusal of any owner or lessee to install or
maintain such telephone system is a misdemeanor.