ST. LOUIS (September 23, 2005) – The Department of the Interior's Office of Surface Mining (OSM) Director, Jeff Jarrett, has honored one of Arch Coal's (NYSE: ACI) mines for demonstrating the best reclamation practices of the past year.

The 2005 national Director's Award was presented in Washington, D.C. to Arch of Wyoming's Seminoe I mine in Hanna for establishing a diverse and productive grass and shrub community that has enhanced the quality of life among the wildlife population, including big game, raptors and small mammals. Seminoe I was selected from a national pool of reclamation sites across the United States.

"I'm extremely proud of the legacy the former Arch of Wyoming mining operations will leave to the state," said Arch Coal's President and Chief Executive Officer Steven F. Leer. "The employees at Arch of Wyoming earned this top honor thanks to their many years of dedication to reclamation excellence."

This is the second year in a row that an Arch Coal subsidiary has won the highest Excellence in Surface Mining award. "We applaud the men and women of Seminoe I mine for their outstanding accomplishments," said Jarrett. "Arch Coal once again set a benchmark for innovative, successful reclamation."

Wyoming's delegation, including Senator Craig Thomas and his wife Susan, and Senator Mike Enzi and his wife Diana, joined Arch Coal at the award ceremony on Sept. 20. Representative Barbara Cubin planned to attend, but was called to vote on the House floor.

Since the awards program began in 1986, Arch Coal and its subsidiaries have won the coveted Director's Award three times, the National Award twice, as well as the Special 25th Anniversary Award and the Good Neighbor Award. For a more complete list of Arch Coal's recent environmental awards, visit www.archcoal.com/aboutus.asp.

The Department of Interior's Office of Surface Mining (OSM) is the agency responsible for regulating the environmental impacts of coal production. Nominations from coal mine operators are first judged by state mining regulatory agencies, which forward state-level winners to OSM Headquarters for final judging at the national level. A panel of experts from OSM completes the final judging. More information is available at: http://www.osmre.gov/activerules01.htm.

Arch of Wyoming is located in the Carbon Basin of southern Wyoming. In addition to the national Director's Award, the Seminoe I mine also won this year's top environmental award given by the Wyoming Department of Environmental Land Quality. Arch of Wyoming previously earned OSM's National Excellence in Surface Mining Award in 1988 for outstanding achievement and innovative reclamation practices in wildlife habitat enhancement.

St. Louis-based Arch Coal, Inc. is the nation's second largest coal producer and mines low-sulfur coal exclusively. Through its subsidiary operations in West Virginia, Kentucky, Virginia, Wyoming, Colorado and Utah, Arch provides the fuel for approximately 7 percent of the electricity generated in the United States. More information is available at www.archcoal.com.

Editor's Note: Photographs of the reclamation site are available upon request.