WRIGHT, Wyo. (September 12, 2005) – Arch Coal, Inc. (NYSE: ACI) today announced that Thunder Basin Coal Company's Black Thunder mine received the 2005 Industry Reclamation and Wildlife Stewardship Award for its cooperative stewardship in the tri-national investigation of ferruginous hawk migration.

The Wyoming Game and Fish Department recognized Black Thunder Mine for its voluntary and proactive efforts to investigate ferruginous hawk migration for future habitat protection at the Hunting and Fishing Heritage Expo awards and sponsors banquet in Casper on Sept. 10.

"Stewardship is an integral part of coal mining, and we're proud that the employees at Black Thunder mine have achieved statewide recognition for their outstanding research efforts," says Kenneth Cochran, president of Arch Coal's Thunder Basin Coal Company. "Our efforts to conserve the ferruginous hawk in Wyoming have been very successful, and very rewarding."

The ferruginous hawk is found throughout western North America. They breed in the U.S. and Canada and winter in the U.S. and Mexico. In addition to Arch Coal, partners of the North American ferruginous hawk project include the Nature Conservancy, Canadian Wildlife Service, USDA Forest Service, and Commission for Environmental Cooperation. More information on the project can be found at www.ferruginoushawk.org.

Black Thunder mine, the program's first industry partner, supports conservation of the ferruginous hawk by reclaiming native grasslands, creating nest sites and encouraging prey species, such as the prairie dog and rabbit. Since 2003, the mine has provided personnel as well as financial support to trap and track migratory movements of ferruginous hawks through the use of small GPS transmitters, including a hawk that nested on Black Thunder's reclaimed land.

Arch Coal's Thunder Basin Coal Company oversees 26,000 acres of land in Wyoming, with roughly 15 percent in permanent reclamation. Black Thunder mine employs more than 850 people and produces nearly 10 percent of the nation's annual coal supply.

Arch Coal is the nation's second largest coal producer and mines low-sulfur coal exclusively. Through its subsidiary operations in Wyoming, West Virginia, Kentucky, Virginia, Colorado and Utah, Arch provides the fuel for approximately 7 percent of the electricity generated in the United States.