Reports of the Inspectors of Mines of the anthracite coal regions of ...

INSPECTORS OF MLNES. 63
Yextilation of Mines.
The gravity of the subject of correctly ventilating collieries that generate
fire-darap gas, and noxious air and deleterious vapors recommends itself to
the thinking public for a thorough practical solution. Tliere needs be a
more vigorous stand taken for destroying its influence than has been the
case heretofore, as the drift and tunnel collieries are yielding to slope and
shaft development, and consequently fire-damp gas becomes more and more
increased, and far more diflicalt for removal, chiefly owing to the great
depth and tlie sj'stem of working the mine in lifts and counter-lifts that it
is next to impossible to keep these large excavations clear of stand gas,
impure air and powder smoke after the first round of shots are fired off in
the morning. To depend upon the action of a 20-horse power exhaust fan
to execute the work of ventilating a large mine is simply out of the question
to do so safely. The owners of collieries to avail themselves of the
benefit of a steam fan generally do so for the purpose of supplying fresh
air to their miners, but it is impossible for the single fan to supply fresh air
and expel the noxious gases that pervade every conceivable aperture in a
mine.
Although tlie velocity of the air currents may appear satisfactory in
quantity their condition may be so loaded with fire-damp and noxious gases
that the safety and health of the men may be endangered, and even the
safety-lamp may not be much of a security when used in such rapid currents
of vitiated air. The discharge of shots will displace the fire-damp that may
be held back by the passing current, and thus become mingled with it in
its exit outward, where it ma}' come in contact with the lamps and explode.
Every mine boss is aware of this circumstance, and does what he can to
prevent explosions, while he cannot control the large volumes of deleterious
air in circ^ilation.
The safe remedy then would be in this event is to erect two separate fans,
one of which to be located at a point as near the working places as could
be, and all the fresh air introduced for ventilating the working places to be
controled by the action of this fan ; while the other suction fan should be
situated at a locality that would reverse the air currents in the old abandoned
or idle works and expel it therefrom ; both these air currents to be
made so distinct from each other in their courses that the inlet air could
not possibly come in contact with the outlet air, and in this manner the
most dangerous mine could be made comparatively safe for men to work in.
The cost of securing a colliery in this manner is but trifling in comparison
to the great good that wou-ld be realized by the operation of the outlet fan.
In collieries that are well ventilated good and intelligent miners are always
in full supply, while in badly ventilated collieries the case is the reverse.
We had 42 fire-damp explosions in the district collieries during the year,
while eleven of these explosions occurred at one colliery, and where the
velocity and volume of air that had been kept in circulation would apparently
be sufiicient to effect a correct ventihition, but the fault rested in the
fact that all the accumulated gases and the inlet air circulated in the same
current on its intake and exit to the outcast fan. The strong currents of
air circulating in the air passages in a mine will check back the gases that
pervade the still open crevices and idle goafs, in the same manner that
strong currents of water would hold back small streams or stagnant pools,
so in like manner is the gases pent up until the space becomes overcharged,
and then it will mingle with the passing current and be carried along with
it. The miner may not be aware of this enemy being in proximity to his
lamp, where he selected a location for its greater security. But some cause
may arise to. necessitate its removal, it may be the miner may light his pipe