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Prior to 1977, it was not mandatory that
highwalls in the U.S. be reclaimed. Hence,
there are considerable highwall reserves that
are readily available for mining. However,
the benches that provide access to these
reserves are quite narrow. This is because
the equipment used for mining prior to 1977 was
much smaller than today’s, and these reserve
areas are located primarily in the coalfields of
the eastern U.S. which are quite mountainous.
Hence, ADDCAR is developing a narrow bench
machine to address this market need/opportunity.
The overall machine length will be radically
reduced from 90 to 45 feet. The
time-tested fundamentals of the ADDCAR
technologies are preserved—just arranged more
compactly and in parallel rather than in a
linear manner.
The central module of the ADDCAR Broad Bench
system is the launch
vehicle. This is the main structure of the
highwall system, housing the electrical and
hydraulic systems, hosting the operator's
compartment and other control functions,
launching the miner into the seam and supporting
the coal handling systems. First, the launch
vehicle is lined up perpendicular to the coal
seam at the desired location. A crawler-mounted
continuous miner
presses into the highwall, cutting the coal and
feeding it onto the unique ADDCAR
conveyor cars,
which are placed at the back of the production
line as the miner advances. This method of
extending the production string means
uninterrupted coal flow. The conveyor cars feed
the coal car-to-car without use of an auger,
which can increase fines. When it reaches the
last conveyor car, the coal dumps off onto a
final conveyor, which sends it to a stacking
conveyor in back of the vehicle. The miner can
drive an entry up to 1,000' into the wall.
Support equipment
includes a stacker conveyor and wheel loader
with forklift attachment. The deck crew remains
under an FOPS canopy; and operators work in
climate-controlled compartments.
This Narrow Bench System has particular appeal
in trench mining applications as well. The
two major benefits are: (1) the reduced length
allows for highwall mining in conjunction with
advancing the box cut because there is space for
the rock and coal trucks to pass behind the
launch vehicle and (2) the overall volume of
rock to be removed is less. |
