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30 THE COAL TRADE BULLETIN.
OUTLINES OF MINE VENTILATION.*
By WILLIAM CLIFFORD,
President of the Clifford Fan Works, Jeannette, Pa.
By the outlines of ventilation, we mean the
broad practice of the art as applied to produce a
safe and sanitary atmosphere in the underground
workings of a coal mine. We do not propose to
treat of gases met with in a coal mine, or of the
principles which underlie the laws of ventilation,
as these are well known and have been fully set
forth in text books and transactions of our mining
institutes.
Whenever man is removed from his natural
habitat, the open air. the change must be met by
some artificial means. We ventilate our houses
and public buildings, because if we failed to do
so, the noxious carbonic acid gas, CO,„ generated
by our breath and the burning of fuel for light
and heat, would soon deprive us of vital energy,
and from persistent deprivation of fresh air, and
closeness of space, sleep and death would ensue.
In mines (particularly coal mines) explosive,
poisonous and irrespirable gases are thrown off,
and it is the province of ventilation to remove,
or to dilute so as to render harmless, these gases.
The principal gases met with in coal mines are
CO, and CH,; CO and H.S are found occasionally,
the former given off by mine fires and the latter
resulting from the imperfect combustion of powder.
Little difficulty seems to have been experienced
for want of ventilation in early drift workings,
which were mere primitive burrowings along a
narrow fringe of outcrop, but towards the end of
the Seventeenth century, shafts became common
in the Midland counties of England. It was to
such shafts that the earliest device for giving
rise to a wind, by means of a water fall, was
applied. The water was allowed to run over the
edge of a large bucket, or to fall on a flat surface,
so as to split it up into numerous small
streams, or ducts, before it fell down the shaft.
•From proceedings of the Engineers Society of Western Pennsylvania.
Paper rend June 3), 1905.
Plan of Ventilating Furnace, Eppleton Colliery, Durham.
This created a feeble wind in the diiection of the
falling water, supplying the vital air for the
breathing of men and animals employed below.
The next step was the fire pan, or basket, consisting
of an iron crate suspended at one end of
a chain, the other end being fastened to the barrel
of a windlass at the top of the shaft. This
flre basket, being lowered to near the bottom of
the shaft, the air above it was heated, the change
of density causing it to rise and set up circulation
which continued so long as the fire was kept
burning. The feeble current thus set up was
suitable only for small mines. In sinking shafts
a bellows worked by hand and delivering air into
a tube, reacning nearly down to the bottom of the
shaft, was used.
Later the fire pan. or basket, gave place to a
furnace fixed near the bottom of the shaft, by
which a continuous and greatly increased volume
o. air was obtained. The evolution of the mine
furnace is a most interesting subject, its latest
form being designed to rarify large volumes of air
with great regularity. Many furnaces in deep
shafts produced over 100.000 cubic feet of air per
minute and some of them much more. That at
the Oaks colliery, at the time of the disastrous
explosion in December, 1866. moved 157,000 cubic
feet of air per minute, while at Hatton colliery.
county of Durham. England. 208,000 cubic feet of
air per minute were moved by three furnaces
placed at the bottom of the shaft 300 yards deep.
The most remarkable example of furnace ven­
tilation, the writer believes, still in operation, is
at Murton colliery, Durham. England. The shaft
is 498 yards deep. The volume of air passed is
aboil. 500.000 cubic feet per minute. To rarify
this vast volume, three furnaces of huge dimensions
are used, and twenty-seven boilers used for
generating steam for hauling, pumping and other
purposes, throw their heated products of combus