Shepherdstown register. [volume] (Shepherdstown, Va. [W. Va.]) 1849-1955, 1902-11-20
Mining Anthracite Coal.

coal consists OF two metnous-strlp-
ping is the process where the coal lies
near the surface of the ground, as it
does in many instances in the anthra-
cite field. The closed work is that
done under ground, or at the bottom
of shaft. Owing to the character of
the deposits, the room and pillar sys-
TEN is employed. When the shaft
cannot be placed so as to reach the
lowest point of the deposit, 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
ladder and two or more for the hoist
ing. a common size OF the hosting
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 sheet iron chutes, ac-
cording as the blind shaft slopes up or
down from the bottom of the shaft
from the surface.
Anthracite is mined with hand ro-
tary drills and black blasting powder.
Dynamite or giant powder is used for
rock work sometimes for driving
gangways and in-some locations Tor
blasting the coal itself, where fire damp
necessitates fameless 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. Fire damp 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 BIZ
luminous coal, and this cost does not
end when the coal is landed at the
surface of the mine. Anthracite as 1t
comes from the mine consists OF Jumps
of various sizes, and intermixed with
these Jumps is a mixture Of rocks.
These Jumps must be broken and
sorted as to size before the anthracite
is ready for the market, since the eco
nomic use Of anthracite requires that
the Jumps must be as near uniform
size as possible and as there is great
er demand for the intermediate sizes,
the larger Jumps must be broken down
to smaller sizes. This elaborate prep
aration greatly increases the cost Of
coal.
Anthracite is prepared for market
in what is known as the coal breaker,
a large building, usually built Of tim
Der, but sometimes of steel and iron.
The coal is broken up by machinery,
consisting Of toothed rolls, after which
it is screened in circular revolving
screens. The slate is picked out by
hand by boys and old men, who cit
along the chutes through which the
screened coal passes. AS far as possi-
ible the work of sorting sizes and pick
ing out impurities is done by machin-
cry. the general plan is TO sort the
coal over inclined bars, then to pass
what goes through the bars over re-
volving or shaking screens, while what
goes through goes directly to the load
ing bins, or else is broken up into
smaller sizes by rolls and then sepa-
rated into the various sizes by screens.
The capacity Of the average breaker is
from two to three thousand tons OF
Goa! a day.
The tendency Of recent years has
been to use more Of the smaller sizes
of anthracite, and consequently the
breaking has been done with this end
in view.
That there is limit to the supply
of anthracite in this country is recog-
nized by all authorities. The extent
of the anthracite field is but $500
square miles. It is located in the State
of Pennsylvania and broadly speaking
is bounded on the west by the Susque-
hama river, on the north by the north
branch fthe same rlver, on the east
by the Delaware and Lehigh rivers,
these three rivers forming the drain
age outlet for the region. According
to Lesley, these beds Of anthracite coal
were originally bituminous in charac-
ter and were deposited at the came
time as the bituminous coal Of Western
and Central Pennsylvania, aud were
subsequently, changed TO their anthra-
cite character by some process Of met
amorpbism. The original contents Of
the anthracite coal deposits have been
estimated to be 19,5078 872.325 tons.
The annual capacity Of the mines is
.o.;,...e5 t, he At 0OO O00 while the