WM. PRESTON LANE, JR., GOVERNOR. 1055

that there is another opening having a weak-wall stopping
or explosion doors that would be in direct line with the
forces coming out of the mine if an explosion occurs, such
opening to be not less than 15 feet nor more than 100 feet
from the fan opening. No main fan shall be placed inside
any mine.

(c) Main mine fans shall be installed to permit the
reversal of air flow and, unless the fan is attended con-
stantly, an automatic device to give alarm when the fan
slows down or stops. This device shall be placed so that it
will be seen or heard by a responsible person. The fan of
a gassy mine shall be on a separate power circuit, inde-
pendent of the mine circuit.

(d) Main-fan installations shall be protected from wood
fire, grass fire, and rubbish for at least 100 feet in all
directions, from the fan installations where physical con-
ditions permit.

The fan shall be inspected daily and a record kept of the
inspection, which shall be open for inspection by interested
persons. When the main fan of a gassy mine fails or stops,
immediate action shall be taken to cut off the power and
withdraw the men from the face regions of the mine. If
ventilation is restored in a reasonable time, the face regions
and other places where methane is likely to accumulate
shall be re-examined by certified or capable supervisors,
and if found to be free from explosive gas, power may be
restored and work resumed. If ventilation is not restored
in a reasonable time, all underground employees shall be
removed from the mine.

Main fans shall be operated continuously except when
the mine is shut down with all men out of the mine. In
such event, after the fan has been started, the mine shall
be examined for gas and other hazards and made safe be-
fore men, other than the examiners, are permitted in the
mine.

100. Booster and auxiliary fans (a) After the effective
date of this Act, the installation of booster fans shall not
be permitted, unless after a finding by the Director of the
Bureau of Mines, that such installation is necessary for
the safe operation and proper ventilation of the mine, that
it would not materially increase the hazard of the mine,
and that such conditions and safeguards as he may pre-
scribe will be complied with. In mines where such fans
are now being used, their use may be continued, but they
shall be surrounded with safeguards as follows: