Iowa County democrat. [volume] (Mineral Point, Wis.) 1877-1938, 1902-08-07
COAL CUTTING BY MACHINERY,
The TWO General Types of Machines.
Now In Use.

Casters Magazine,-The two gen
eral types of coal cutting machines
in most common use in the mines of
the United States may be classed
under the heads of pick or punch
ing" machines. and the Chain breast
although few "longwall" machines
are in successful use in some Of the
thin seams of the western states.
The method of mining in America is
usually some adoption of the pillar
and-room" or "stalland-piIlar' sys-
tenn and most of the iongwall ma
chimes made in the United States are
shipped to Europe, where that system
OF mining is generally practced.
There are in the United States,
seven extensive manufacturing es-
t. ishments making a specially of
coal mining machinery. Three of
these make pick machines and four
manufacture chain cutting machines,
These types of mining machines have
been brought to such degree of
efficiency that, it is safe to say, there
are comparatively few bituminOus
coal mines, operated upon an extern
sive scale. that could not with adyan-
tage be equipped with mining ma
chimes. There is but ono adverse
condition that has not been success
! fully surmounted and that is the in
| Clination of the vein when the dip
exceeds II or Is degrees, Some Of
| the pick machines have been used in
mines where the inclination was as
much as % degrees; but the work
was slow and difficult, and it was
only from the fact that the price of
| labor was high that the machine was
able to compete with it. The trouble
does not lie so much in the actual
cutting but in the difficulty of NOV
! ing the machines from place to place.
! Manufacturers do not care to run
| the risk of failing, and prefer not to
| install machines where the dip eX-
I ceeds, say, II degrees. BY the use of
self-propelling trucks it has been
| found possible to use chain machines
! in mines having this amount of in
clination from the HORIZONTAL but
! that is about the maximum. The
self-propelling truck also enables the
chain machines to be used in mines
where the seam is so thin that II
would be otherwise impossible to
draw the machine or move it up to
! the face of coal, as neither horses
nor mules could go into the room I'M
! less some of the floor we're taken up
or the top taken down
All of the pick machines in success.
rul operation at the present time are
driven by compressed air, although
C.e company claims to have develop
ed an DISQUALIFICATION pick ma
chine which has overcome the me
chanical difficulties heretofore efneC-
j .e against the use of any other
than an air-driven pick machine.
Most of the chain machines and all
rf the few lODgwall machines in
American use employ electricity as a
motive power In some of the long.
wall machines of British make com
pressed ali supplies the power. In
some mines where gas is present in
dangerous proportions, and is apt TO
be exploded by an electric spark, or
where other conditions are against
electric installation, chain machines
operated by compressed air are in
use One of the principal objections
offered to the use Of air cor a chain
machine Is the low temperature pro
duced about the legs Of the operative
by the expanding air from the ex-
haust This cold is sufficient to cover
the exhaust pipe with frost and to
produce rheumatism in the miners
legs