ST. LOUIS (September 16, 2008) - Arch Coal, Inc. (NYSE:ACI) today announced that it again earned a spot on the 2008 InformationWeek 500 list. This marks the third consecutive year that Arch Coal has been ranked as one of the most innovative companies by InformationWeek. The 2008 InformationWeek 500 companies were revealed on September 15, 2008 at a gala awards ceremony held during the annual conference at the St. Regis Resort in Monarch Beach, Calif.

"Real business needs drive our technological innovation at Arch Coal," said Chairman and CEO Steven F. Leer. "We are pleased to be listed among highly respected companies who set the benchmark for innovative business technology strategies and solutions."

Arch Coal is the only coal producer among this year's InformationWeek 500.

"For 20 years, the InformationWeek 500 has honored the most innovative users of business technology," said InformationWeek Editor-in-Chief Rob Preston. "Year after year, InformationWeek 500 companies harness technology to improve efficiency, boost productivity, drive revenue, and establish a competitive advantage. We applaud this year's winners, and the CIOs and other executives whose ingenuity and risk taking are at the center of business technology innovation."

InformationWeek has identified and honored the nation's most innovative users of information technology with its annual listing, and has tracked the technology, strategies, investments and administrative practices of America's best-known companies. The list is unique among corporate rankings because it spotlights the power of innovation in information technology, rather than simply identifying the biggest IT spenders. Additional details on the InformationWeek 500 can be found online at www.informationweek.com/iw500/.

St. Louis-based Arch Coal is one of the nation's largest coal producers, with 2007 revenues of $2.4 billion. Through its national network of mines, Arch Coal provides the fuel for approximately 6% of the electricity generated in the United States. Arch has amassed numerous national and international awards for the innovative use of new technologies, including Business Week's Web Smart 50 and CIO's Bold 100.