coal trade bulletin - Clpdigital.org

48 THE COAL TRADE BULLETIN.
The width over all the machine is 5 feet, length
17 feet, with an 8-foot cutter bar, and height of 5
feet 6 inches.
It has been found that by cutting the coal seam
in the center, it requires only two small shots for
the top, and two for the bottom bench which lessens
the danger of damaging the roof, and practically
eliminates blown-out shots. The machine has
been the means at this mine of giving a cleaner
product of coai, more rapid cutting of coal at less
expense per ton, and a good deal safer method of
mining coal.
The entries of these mines are driven 10 feet and
the rooms 15 feet in width. The operation of
the machine is as follows: when the machine,
which is self-propelled, is moved into the room.
The machine is then started, and the machine
pulled towards the face, forcing the cutter bar into
the coal to a depth of about 8 feet. When the
cutter bar has been reached the full depth of the
coal, the feed rope is attached to an extension arm
which is securely bolted to the lower part of the
truck, the rope being taken around a sheave, and
the end of the rope fastened to the machine proper.
With this hitching the cutter bar is swung across
the face, the speed of the cutter bar being about
32% inches per minute, at the extreme end of
the cutter bar. The cue across the face is completed
when the cutter bar stands at an angle of
about 20 degrees to the left of the track, where
the cutter bar is again automatically locked. The
feed rope is then carried to the machine over the
proper sheave wheels, and attached to a jack pipe
set about 20 to 30 feet from the face between the
track and the left-hand rib.
The feed is then started, and the machine with
truck is pulled back, cutting the left-hand rib,
as the machine is pulled from the face. When
the cutter bar is clear of the rib, it is swung into
Jeffrey Turret Coal Cutter C utting at the Face of a Coal Seam
an anchor 2% inches in diameter is first drilled a central position to the track, the machine low­
in the coal under the band to be cut and about ered, and the self-propelling gear thrown in. The
in line with the left hand rail. An anchor is machine is then ready to be propelled to the next
fitted into this hole, and the feed rope attached. working place.
The machine is then turned on the turret by hand
toward the right hand rib, making an angle of
about 15 degrees with the track, where it automatically
locks the cutter bar in position.
The cutting is done in the shale at the bottom
of the band, with the bottom nose of the bits cutting
into the coal about % inch, which causes the
shale to fall down in the kerf, after which it is
cleaned out and loaded in cars and hauled out of
the mine. This insures an absolutely clean product
of coal.
Some idea of the performance of this machine
can be obtained when it is considered that a 15foot
place can be cut in 11 minutes from the time
the machine enters the room until it is ready to