Published in the August 2006 American Longwall Magazine
There is absolutely no way to miss Massey Energy's Elk Run Coal complex: with nearly 18 miles of beltline, much of it outside the portal, the overland conveyors stretch and lace through three southern West Virginia towns and arrive at a two preparation plants, Marfork and Chess Processing. This drift mine is no sleeping lion - it is wide awake and everyone knows it.
Longwall production ceased after 10 years at Massey's Upper Big Branch, and the August 15 commencement at Massey's Logan's Fork longwall was perfectly timed to ensure a smooth transition and no loss of production momentum. Massey executives admit the longwall is not intended to be a long-term addition to its line-up, but rather a "pinch hitter" of sorts in the company's strategic planning as it moves through its ninth decade of existence.
The longwall equipment from Upper Big Branch (UBB) was transported to resume duties at Logan's Fork, which has planned panel width of 1000 feet and length range of 6300-8000ft. While Massey's new operation balances out the production scales for the company, plans for its long-term future will be considered.
According to vice president and chief operating officer Chris Adkins, it then could be back to UBB or a new start-up at one of two other company properties, Indiana Creek or Mammoth. He notes that the final decision will be driven by the market at that time as well as the direction that makes the most financial sense.
Adkins cited the diverse reserve holdings Massey Energy has as the main reason the freedom exists for it to move with the market. "We've been able to carve out mining areas and say 'This would be a good longwall'," he said.
Logan's Fork was such a decision. The Elk Run Coal complex mines from two seams (Powellton and Eagle), not uncommon for the central Appalachia area, and the former will serve as home to the Joy 7LS-1 AC shearer.
The shearer boasts a 62-inch drum diameter and installed power of 4160 volts, including a 700hp ranging arm. The accompanying Longwall Associates face conveyor features an 890mm pan and 42mm chain that runs at 343fpm. Three Joy 1000hp motors round out the powerful, compact package.
Cutting and seam heights at identical 72in makes it not only comfortable for workers to travel about, but is another key efficiency factor for the newest longwall on Massey's log. In general, Adkins said, the coal height runs between 60in and 72in mine-wide but it holds that horizon of about 72in.
The coal seams of central and southern West Virginia, the majority of what encompasses central Appalachia, are nothing if not vast and diverse. In the case of Logan's Fork, the Powellton seam is overlain by a shale layer ranging in width from 4-20ft. Above that is 30-60ft of sandstone, both typical of the area's geology. Also common to the mountainous area is the mine's depth of cover, which is 700-1000ft.
The face, which is estimated to retreat 36ft per day and produce 1.5 million tons in its first year of operations, is expected to produce up to 5500 tons per hour. That rate, said Adkins, will easily be handled by the belts.
Like many other operations in that area of central Appalachia, gas is an issue but it is one rectified through liberation and ventilation methods. "We liberate about 80,000cfm per day," said Adkins, adding that seam degasification has so far not been performed and two fans will be put into place to neutralize it. Its ventilation circuit centers around keeping positive pressure on the gob through a push-and-pull system that extends to the farthest reaches of the complex.
The first longwall move for Logan's Fork was one of a rare scope for any operation, involving the transport of equipment some 14 miles from the UBB face. A 500t crane was brought in to move all of the 176 Joy shields, each with a 1280t yield and weighing in at 26-32t apiece. Each 42-88in working range unit was dropped down a ventilation hole to shorten transport time, increase efficiency and reduce the potential for incident.
When the first panel move does take place, Adkins said the time window will be measured from past experiences. "We measure longwall moves from the time you start taking your last cut before bolting the face; depending on conditions, they generally take seven to ten days." At that time, workers will use 8-10ft cable bolts to secure the longwall face.
The development sections at Logan's Fork are also moving along via room and pillar method using Joy 12-12 continuous miners and 10SC shuttle cars. Four gate headings have been driven and two panels were developed in advance of the longwall move from UBB. The pillars of these sections, which measure 105ft by 90ft, are developed on 48in belts with a 2000tph rating; output is mined in these areas at an average 500-600ft each day.
Roof control is achieved with Jennmar 6ft torque tension bolts, spaced at 4ft with 8ft to 10ft cable bolts in every row. To reduce rib rolls and control draw rock for the safety of the workers and belt, the operation also uses mesh on headgate entries.
Once coal is cut from the mine's face and active development sections, the output begins its journey to the preparation plant on a Continental Conveyor system at 5500tph. The beam stage loader and crusher equipment were also produced by Joy.
The heart of this complex, its success and its continued efficiency is thanks to a "Glory Hole", a 10ft diameter vertical lowering tube drilled between the two seams (Eagle and Powellton) that enables coal to drop 190ft to an established belt system. Adkins said it was a welcome addition to the mine and, given its complex logistics, made financial and economic sense and became a great solution to an obstacle which may have stopped other operations in their tracks.
With the significant amount of conveyor footage...click here to read on.
