“Underground production at Mountain Laurel is expected to increase from 1.8 million metric tons (mt) coal in 2007 (development work) to more than 3.6 million mt of clean coal in 2008 thanks to our longwall installation,” said Greg Dotson, mine manager, Mountain Laurel.

Mountain Laurel operates three development sections and now a longwall section in the 1.8- to 2.1-meter Alma coal seam. Since longwall production began, the new equipment has been averaging more than 3,175 mt per shift, almost exactly what was predicted, according to Dotson. “One thing that did pleasantly surprise us was how quickly our production ramped up,” said Dotson. “Our crews were averaging 8 meters of retreat per shift by the beginning of the second week of operation.”

The longwall system comprises 176 automated self-advancing 945-mt shields; a 600-kW 7LS2A shearing machine, together with an UltraTrac 2000 haulage system with 1,000-mm raceway pans and 42-mm flat-link chain driven by a three 745-kW transmission. According to Joy, the armored face conveyor and stageloader have a coal-clearing capacity of 3,628 mt/h and a surge capacity of 4,717 mt/h.

“In the first six months of operation, the Mountain Laurel longwall has produced more than 3.45 million mt raw coal, and retreated the 305-meter long face more than 2,745 meters. “Not too bad for our first panel,” said Jeff Roberts, longwall coordinator, Mountain Laurel.

Upon completion of the current panel this spring, Mountain Laurel will move the longwall to a new panel. “With the introduction of the new electronic control system on the shearer—and in combination with a seasoned longwall crew and experienced maintenance, service and support personnel, we believe the Mountain Laurel longwall is positioned to be a major producer for Arch Coal for the next decade,” said Roberts.