WASHINGTON, D.C., Oct 18, 2010 -- Arch Coal, Inc. (NYSE: ACI) today announced that the U.S. Department of Interior honored its Coal-Mac, Inc. subsidiary with one of the top national environmental awards of the year.

Coal-Mac was recognized with a 2010 National Award for Excellence in Surface Mining for exhibiting exemplary environmental care for the construction of its Duty Branch overland conveyor belt line and adjacent slurry pumping project. The conveyor transports nearly 3 million tons of coal annually to the rail loadout, eliminating the need for trucking on public roads and reducing the use of diesel fuel. The newly constructed seven mile slurry pipe line includes multi-walled pipe and a fiber optic system that enables real-time monitoring and flow control to help ensure environmental protection.

"Coal-Mac's excellence has earned the respect of the Interior Department and our peers," said Arch's Chairman and CEO Steven F. Leer. "I applaud the employees of Coal-Mac for being recognized for their excellence in environmental stewardship again and again. The enduring results are a testament to their achievement."

Coal-Mac, Inc. is a subsidiary of Arch Coal, Inc. Coal-Mac is located near Holden, W.Va., and employs approximately 300 people. In the past five years, the employees of Coal-Mac have received 11 national and state awards for environmental stewardship, including the U.S. Department of Interior's National Good Neighbor Award.

St. Louis-based Arch Coal is the nation's second largest coal producer. The company's core business is providing U.S. power generators with cleaner-burning, low-sulfur coal for electric generation. Through its national network of mines, Arch supplies the fuel for approximately 8 percent of the electricity generated in the United States. An extensive list of environmental and safety awards is available at http://www.archcoal.com/aboutus/awards.aspx.