Omaha daily bee., 1902-11-05
MINING
How Hard Goa is Taken Out and
Prepared for Use.

wv ~
Prepared for Use.
The process of mining anthracite coal,
says the Washington Star, consists. OF two
MISUNDERSTANDING and closed work. Strip
ping Is the process where the coal lies
near the surface OF the ground, as IL does
in many instances in the anthracite field.
The closed work is that done underground,
or at the bottom OF a shaft. Owing to the
character OF the deposits, the room and
pillar system 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 a depth OF 1000 feet. usually have
several compartments, enc for the pumpway
and ladder and two or more for the hoist
ing. A common size OF the hosting COM
partments is 7x12 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-
eording to the inclination of the shaft. ac-
cording as the blind shaft slopes up or down
from the bottom OF the shaft from the sur
face.
Anthracite is mined with hand rotary
drills and by black blasting powder. Dyna-
mite or giant powder is used for rock
| nOuANAtAnNo kalbN ayp ~
in some locations for blasting the coal itself,
where hre damp necessitates a hameless
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 per 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 %bituminous
coal, and this cost does not end when the
coal is landed at the surface of the mine.
Anthracite as Il comes from the mine con-
sists OF Jumps OF various sizes, and inter-
mixed 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 economic
use Of anthracite requires that the lumpA
must be OF as near uniform size as posi-
bic, and as there is a greater demand for
the intermediate sizes the larger Jumps
must be broken down TO smaller sizes.
This elaborate preparation greatly in
creases the cost OF the coal.
Anthracite is prepared for market in
what is known as the coal breaker. a large
building usually bullt OF timber, but some.
times Of steel aud iron. The coal is broken
up by machinery, consisting OF toothed
rolls, after which Il is screened in cir
cular revolving screens. The slate lie
picked out by hand by boys and old men,
who sit along the ehutes through which
the screened coal passes. As far as pos
sible the work of sorting siEes and picking
out impurities Is done by machinery. Til
general plan is TO sort the coal over In
clined bars, then to pass what goes through
the bars over revolving or shaking screens
while what goes through goes directly e
the loading bins. or else Is broken up int
smaller sizes by rolls and then separated
into the various sizes by screens, The ca
paeity Of he Eygfssa breaker is from
1000 10 5000 tons Of coal a day.
The tendency OF recent years has been Il
use more OF the smaller sizes Of anthra