30 CFR § 75.313
Main mine fan stoppage with persons underground.
(a) If a main mine fan stops while anyone is underground and the
ventilating quantity provided by the fan is not maintained by a back-up fan
(1) Electrically powered equipment in each working section shall be
(2) Other mechanized equipment in each working section shall be shut
(3) Everyone shall be withdrawn from the working sections and areas
where mechanized mining equipment is being installed or removed.
(b) If ventilation is restored within 15 minutes after a main mine fan
stops, certified persons shall examine for methane in the working places and
in other areas where methane is likely to accumulate before work is resumed
and before equipment is energized or restarted in these areas.
(c) If ventilation is not restored within 15 minutes after a main mine
(c) Everyone shall be withdrawn from the mine;
(2) Underground electric power circuits shall be deenergized. However,
circuits necessary to withdraw persons from the mine need not be deenergized
if located in areas or haulageways where methane is not likely to migrate to
or accumulate. These circuits shall be deenergized as persons are withdrawn;
(3) Mechanized equipment not located on working sections shall be shut
off. However, mechanized equipment necessary to withdraw persons from the
mine need not be shut off if located in areas where methane is not likely to
migrate to or accumulate.
(d) When ventilation is restored--
(i) No one other than designated certified examiners shall enter
any underground area of the mine until an examination is conducted as
described in §75.360(b)
through (e) and the
area has been determined to be safe. Designated certified examiners shall
enter the underground area of the mine from which miners have been withdrawn
only after the fan has operated for at least 15 minutes unless a longer
period of time is specified in the approved ventilation plan.
(ii) Underground power circuits shall not be energized and
nonpermissible mechanized equipment shall not be started or operated in an
area until an examination is conducted as described in §75.360(b)
through (e) and the area has been determined to be safe,
except that designated certified examiners may use nonpermissible
transportation equipment in intake airways to facilitate the making of the
(2) If ventilation is restored to the mine before miners reach the
surface, the miners may return to underground working areas only after an
examination of the areas is made by a certified person and the areas are
determined to be safe.
(e) Any atmospheric monitoring system operated during fan stoppages shall be intrinsically safe.
(f) Any electrical refuge alternative components exposed to the
mine atmosphere shall be approved as intrinsically safe for use during
fan stoppages. Any electrical refuge alternative components located
inside the refuge alternative shall be either approved as intrinsically
safe or approved as permissible for use during fan stoppages.