The Democratic advocate. [volume] (Westminster, Md.) 1865-1972, 1902-11-01
Mining Anthracite Coal.
From the Washington STAR.

1
The process of mining anthracite coal
consists of two methods stripping and
closed work. Stripping is the process
where the coal lies near the surface of the
ground, as it does in many instances in the
anthracite field. The closed work is that
done under ground, or at the bottom of a
shaft. Owing to the character of the de-
posits, the room and pillar system is en-
ployed. When the.shaft cannot be placed
SO as to reach the lowest point of the de-
posit, the coal below is reached by inside
or blind shafts or inside slopes. These
shafts, which are sometimes sunk to depth
of 1000 feet, usually have several COM
partments, one for the pumpway and lad
der and two or more for the hosting. A
common size of the hoisting compartments
is seven by twelve feet. The coal is
brought to the bottom of the shaft from
the inside or blind shafts by means of small
cars, and in some instances sheetiron chutes,
according as the blind shaft slopes up or
down from the bottom of the shaft from
the surface.
Anthracite is mined with hand rotary
drills and by black blasting powder. Dy-
Mantle or giant powder is used for rock
work, sometimes for driving gangways and
in some locations for blasting the coal it
self, where fire damp necessitates fame
less explosive. The mines are ventilated
by rotary FANS The law requires that
each miner shall be supplied with at least
200 cubic feet of air minute. Firedamp
is prevalent in many of the anthracite
shafts, necessitating the use of safety lamps
by miners
The cost of mining anthracite coal is
greater than the cost of mining bituminous
coal, and this cost does not end when the
coal is landed at the surface of the mine.
Anthracite as it comes from the mine con-
sists of Jumps of various sizes and inter-
mixed with these Jumps is mixture OF
rocks. These Jumps must be broken and
sorted as to size before the anthracite Is
ready for the market, since the economic
use of anthracite requires that the Jumps
must be of as near uniform size as possible,
and, as there is greater demand for the
intermediate sizes, the larger Jumps must
be broken down to smaller sizes. This
elaborate preparation greatly increases the
cost of coal.
Anthracite is prepared for market in
what is known as the coal breaker, a large
bnilding, usually built of timber but some
times of steel and iron The coal is bro
ken up by machinery, consisting Of tooth
rolls, after which it is screened, in circular
revolving screens. The slate is picked out
by hand by boys and old men, who sit
along the chutes through which the screen
ed coal passes As far as possible the
work of soorting sizes and picking out i'm
purities is done by machinery. The gen.
eral plan is to sort the coal over inclined
bars, then to pass what goes through the
bars over revolving or shaking screens,
while what goes through goes directly to
the loading bins, or else is broken up into
smaller sizes by rolls and then separated
into the various sizes by screens. The
capacity of the average breaker is from
two to three thousand tons Of coal day.
The tendency of recent years has been
to use more of the smaller sizes of anthra-
cite, and consequently the breaking has
been done with this end in view.
Many estimates are given as to the cost
of mining and marketing anthracite Here
is one from Anthracite Coal Operators
letter, which refers particularly to the
smaller sizes of anthracite Mining and
preparation, Sl25 ton; transportation
to New York, 81. 35 ton, making total
of S2. 60 ton.
That there is a limit to the supply of
anthracite in this country is recognized by
all authorities. The extent Of the anthra-
cite field is but $500 square miles. 1t is
located in the State of Pennsylvania and,
broadly speaking, is bounded on the west
by the Susquehanna river, on the north by
the north branch of the same river, on the
east by the Delaware and Lehigh rivers,
these three rivers forming the drainage
outlet for the region. The valleys con-
tanning the deposits generally run from
north to south. The greatest length OF
any of these valleys is l20 miles, while the
width is perhaps 30 miles. According to
Lesley, these beds of anthracite coal were
originally bituminous in character and were
deposited at the same time as the bituml
nous coal of Western and Central Penn
sylvania, and were subsequently changed
to their anthracite character by some pro-
cess Of metamorphism. The original con-
tents of the anthracite coal deposits have
been estimated to be 19, 507, 872, 325 TONS
The annual capacity of the mines is esti-
mated to be 67, 600, 900, while the market
will take less than $4,000, 900 tons. 1t
is estimated that there is 500, 900, 900
invested in the anthracite industry, with an
annual profit of from S85, 600, 600 to
800, 600, 900, added to by freight traffic
net earnings of $40, 600, 900 a year.
His Dog, Moreover.