Arch Coal Inc a Delaware corporation was organized in 1969. The Company is a coal producer in the United States. The Company's business segments are based on the coal producing basis in which the Company operates. Its operating segments include the Powder River Basin segment, with operations in Wyoming and the Appalachia segment. These geographically distinct areas are characterized by geology, coal transportation routes to consumers, regulatory environments and coal quality. The Powder River Basin is segment, with operations in Wyoming; and the Appalachia (APP) segment, with operations in West Virginia, Kentucky, Maryland and Virginia. The Powder River Basin is segment: The Company acquired the coal assets of Atlantic Richfield Company, which it refer to as ARCO. This acquisition included the Black Thunder and Coal Creek mines in the Powder River Basin of Wyoming, the West Elk mine in Colorado and a 65% interest in Canyon Fuel Company, which operated three mines in Utah. The Appalachia region is further divided into north, central and southern regions. Central Appalachia includes eastern Kentucky, Tennessee, Virginia and southern West Virginia. Northern Appalachia includes Maryland, Ohio, Pennsylvania and northern West Virginia. Southern Appalachia covers Alabama. The Company's underground mines are typically operated using one or both of two different techniques: longwall mining and room-and-pillar mining. Longwall mining involves using mechanical shearers to extract coal from long rectangular blocks of medium to thick seams. Room-and-pillar mining is effective for small blocks of thin coal seams. It sells all of its coal to power plants, steel mills and industrial facilities. The Company's sales, marketing and trading force is mainly based in St. Louis, Missouri and consists of sales and trading personnel, transportation and distribution personnel, quality control personnel and contract administration personnel. Its main domestic competitors include Alpha Natural Resources, Inc., Cloud Peak Energy, CONSOL Energy Inc., Patriot Coal Corporation, Peabody Energy Corp. and Walter Energy, Inc. Federal, state and local authorities regulate the U.S. coal mining industry with respect to matters such as employee health and safety and the environment, including protection of air quality, water quality, wetlands, special status species of plants and animals, land uses, cultural and historic properties and other environmental resources identified during the permitting process.