30 CFR 57.4202 - Fire hydrants.
If fire hydrants are part of the mine's firefighting system, the hydrants shall be provided with -
(a) Uniform fittings or readily available adapters for onsite firefighting equipment;
(b) Readily available wrenches or keys to open the valves; and
(c) Readily available adapters capable of connecting hydrant fittings to the hose equipment of any firefighting organization relied upon by the mine.