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Longwell mining proves successful for North Fork coal operation By Ta:asBH 8al~a elan Wrrya The introduction of longwall mining in the United States follow- ing World War II has revolution- ized the coal industry. Although longwall mining was practiced on a very small scale in he U.S. in the late 1800s and eazly 1900s,[he process did not take told until the 1950s. Interest in longwall mining was ~enewed after World War II by the possibilities of using the German- ieveloped plow (or planer) and 'panzer," or armored face convey- tr. The plow is pulled across the :oalface while riding on a base that tides under the conveyor. It shaves rif two to four inches of coal that pills onto the conveyor. In 1952, Eastern Gas and Fuel \ssociates, with support from the J.S. Bureau of Mines, tested long- vall mining with a plow and face onveyor at the Statesbury mine, ear Beckley, W.Va., to learn if his type of equipment could be sed to extract American coal. The test was successful and the quipment was used in three other longwall operations between ]952 and 1958. The longwall technique is rela- tively new in the North Fork. Mountain Coal's West Elk mine in- stalled the system in June 1992. It became operational the following month. In March of this year, the Ener- gy Information Administration, an independent statistical and analyti- cal agency within the Department of Energy, published a 60-page book on longwall mining, available through the Government Printing Office. This interesting book gives in- sights into the development of longwall mining in this country, and compares it with traditional mining methods. Excerpts from this publication are included in this article, along -with statistics supplied by West Elk Mine. By 1993, longwall mining ac- counted for 40 percent. of the na- tion's underground coal production - up from 27 percent in 1983. Ta- bor productivity at longwall mines more than doubled between 1983 and 1993. The longwall system has greatly increased productivity at West Elk Mine at Somerset. In February of this year, Mountain Coal pur- chased afull-page ad in the Delta County /ndependentto congratu- late its employees for their safety record and their productivity in 1994. The ad said, "We mined and shipped over 4.1 million tons of high quality, low sulfur coal [o customers in Colorado, Nevada, Texas, Missouri, Tennessee, Illi- nois and Japan. We established two coal production world records for the most tons produced by a long- wall operation in a single shift: 21,387 tons in 10 hours, 18,487 tons in eight hours. We also estab- lished new West Elk Mine mile- stones: 48,475 tons produced in a single day, 455,110 tons produced in a single month, 411,332 tons shipped in a single month." DiFFERENCFS EXPLAmVED Longwell mining is one of two basic methods of underground coal mining. The other is room-and-pil- lar mining, historically the method used in the Uttited States. In roon and-pillar mining, "rooms" are ea coveted, and pillars of coal are le. in place between the.rooms to suI port the mine roof. In contras longwall mining involves the e+ sentially complete extraction of th coal contained in a lazge rectangt lar block or "panel" of coal, an the roof in the mined-out area is al lowed to collapse. The sequence of operations i longwall mining is basically sim ple, the EIA reports. A rectangula longwall panel, averaging pearl; 800 feet wide, 7,000 feet long and seven feet' high, is "blocked out by excavating passageways atount its perimeter using room-and-pitta mining. Excavation of the coal in tht panel is an almost continuous op erasion. Working under the stee canopies of hydraulic, movablt roof supports, a coal cutting ma chine runs bay~C and forth along tht 800-foot face, taking a cut ranging anywhere from a few inches to ? I/2 feet deep during each pass. See Longwell mining, Pege 1: 1, n+raem< a tapoa cos rats. Dan Wln b Eaykshea YFCupkp aaYx camels wry wlre iESE DIAGRAMS ,TAKEN FROM THE Department of Energy's book ~ Longwell Mining, show the basic differences between underground ping systems. On the left is the typical room-and-pillar meshed, the most common way to mine coal underground. The longwall method, illus- trated on the right, is used to mine large blocks of coal where the bed is relatively flat and thick e. eon Hoar 1OSar4 eravrar