The Indianapolis journal. [volume] (Indianapolis [Ind.]) 1867-1904, 1902-10-15
MINING ANTHRACITE.
How Hard Coal Is Taken Out and
Prepared for Use.

Washington Evening Star.
The process OF mining anthracite coal
consists of two misunderstanding and
closed work. Stripping is the process where
the coal lies near the surface of the ground,
as 1T does in many instances in the anthra-
cite field. The closed work is that done
underground. 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 blind
Shafts, or inside slopes. These shafts,
which sometimes sunk to a depth of
1000 feet, usually have several compart-
ments. one for the pumpway and ladder
and two or more for the hosting.
common size Of the hosting compartments
is seven by twelve feet The coal is brought
to the bottom or the shaft from the inside
or blind shafts by means or small cars, ana
in some instances sheet-iron chutes, accord
ing to the inclination of the shaft, accord
ing 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
work, sometimes for driving gangways and
in some locations for blasting the coal
itself, where fire damp necessitates flame
less explosive. The mines are ventilated
by rotary fans. The law requires that eacn
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 1t 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 Jumps
must be of as near uniform size as possible pre-
intermediate sizes the larger Jumps must
be broken down to smaller sizes. ms
elaborate preparation greatly increases the
Anthracite is prepared for market in what
is known as the coal breaker, large
building usually built Of timber, but some
times of steel and iron. The coal Is broken
up by machinery, consisting of toothed
rolls, after which il 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 screened coal
passes. AS far possible the work or sort
ing sizes and picking out impurities is done
by machinery The general plan is to sort
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 aver
age breaker is from two to three thou-
sand tons Of coal 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.
Many estimates are given as TO the cost
of mining and marketing anthracite. Here
is one from the Anthracite Coal Operators
Association letter, which refers particular
ly to the smaller sizes OF anthracite: Min
ing and preparation, 81 Is per ton; trans
pOrtatfon to New YORK, $l.Z5, making a
total of $3.50 per ton.
That there Is a limit to the supply Of an
thracite in this country is recognized by all
authorities. The extent of the anthracite
field is but 1900 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 contain
ing the deposits generally run from north
to south. The greatest length of any OF
these valleys is 12o miles. while the width
| is perhaps thirty miles. According to
Lesley, these beds of anthracite coal were
originally bitumnous in character, and
were deposited at the same time as the
bituminous coal of western and central
changed to their anthracite character by
some process of metamorphsm. The origf-
nal contents of the anthracite coal de-
posits have been estimated to be 19507,-
| S72.325 tons. The annual capacity of these
mines Is estimated to be 67.000, 900, while
| the market will take less than $4,000, 90f
| tons. 1t is estimated that there is $780,
100000 invested in the anthracite Industry
| with an annual profit Of from $Ss.000.0t0 to
| $100 000, 900, added to by freight traffic net
| earnings of $40,000,0Q0 a year.