coal trade bulletin - Clpdigital.org

50 THE COAL TRADE BULLETIN.
age ways. The standard dimensions of all entries
are 9 feet wide by 6 feet high, bottom being taken
up or top removed, as necessary, to give proper
height and grade. The grades range from one to
three per cent. The butt or panel entries are
turned at right angles to the main entry, usually
on the double-entry system, or on the single-entry
system, when required by conditions. Rooms are
turned from these butt entries on 50-foot centers,
the standard dimensions giving a 25-foot room and
a 25-foot pillar; although where top is good, the
rooms are carried wider than this. They are
driven to a depth of 300 feet.
The top encountered uniformly in both mines is
a strong, black slate, and the bottom is of firm
fire-clay. All of the coal at the Furnace Run
mines is cut with machines. The entries, narrow
places ancl rooms are
driven hy this
means, and pillars
will eventually be
drawn by the same
method.
A trial of various
types of electric
chain machines resulted
in the adoption
of Sullivan
IRONCLAD continuous
coal cutters, of the
direct current pattern,
cutting to a
depth of 6% feet under the coal, and giving a kerf
or mining 5% inches in height. At the present
time the company has 17 of this pattern in service
in its various mines. The high cutting capacity
of the Sullivan IRONCLAD and its strength
and durability have provided satisfactory speed in
production, as well as economy in repair costs.
The operation of the IRONCLAD machine is illus­
trated by the accompanying series of pictures.
Figure 1 shows the machine on its self-propelling
truck, moving from the heading into the room.
This picture shows the customary method of transporting
all equipment used with the machine on
it when moving.
Figure 2. The machine has been squared with
the right hand rib, and is ready to make the sumping*
or rib cut.
Fig 3. This picture
was taken to
show how the IRON­
CLAD machine is
handled in manipulating
the feed chain
ancl the take-up rig
when an obstruction
is encountered in the
coal, such as a sulphur
ball, spar or
vein. The operator
first throws the body
of the machine forward,
to cut in front
of the obstruction.
Figure 4. This
shows the result of
a. break-down shot after niining with a Sullivan
IRONCLAD coal cutter and indicates how well the
coal shoots, after this machine. It also shows
how bloeky this coal is, and how readily it may
be wedged out and loaded in large lumps, the most
profitable condition for the market.
When the undermining is completed, the loaders
bore holes for blasting to the depth of the niining.
Fig*. 2.
namely, 61/, feet. Two shots are placed in the
entries and three in the room. In the entries the
shots are at each side, about a foot from the rib,
while in the room a center break-down shot is
fired first, followed by the rib shots, which are
placed in the same manner as in the entries. The
holes are bored straight in from the face. Black
powder is used for shooting, the cartridges being