ST. LOUIS (August 31, 2006) – Arch Coal, Inc. (NYSE:ACI) today announced that it has achieved the ranks of the InformationWeek 500 list for its strategic use of advanced information technologies. The top 2006 InformationWeek 500 companies will be revealed at a gala awards ceremony on September 11 in Rancho Mirage, Calif.

"It is rewarding to receive public recognition for taking a progressive approach in our business practices," said Michael T. Abbene, Arch's vice president and chief information officer. "Our goal is to continually identify and harness new technologies to improve our interaction with our customers, vendors and employees."

Arch Coal earned a spot on the 2006 InformationWeek 500 list for its leadership in e-commerce process improvements and key strategic efforts, most notably the launch of a new employee portal – Arch@Work – earlier this year. The Arch@Work site provides every employee with a unique user experience, featuring customizable settings and online collaboration.

"It took more than a year to conceptualize, design, populate, test and launch our employee portal," said Abbene. "The investment is paying off. Now we're providing online solutions to employees' everyday work demands – and that creates efficiencies." According to WebTrends, traffic on the Arch@Work portal has outpaced Arch Coal's previous intranet by 300% in length per visit.

This marks the 18th year that InformationWeek has identified and honored the nation's most innovative users of information technology with its annual listing. 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 at www.informationweek.com/iw500/.

"The InformationWeek 500 honors today's leading companies who set the benchmark for business technology strategies and projects," said InformationWeek Publishing Director Fritz Nelson. "The companies on our list are some of the most innovative users of technology."

St. Louis-based Arch Coal is the nation's second largest coal producer, with 2005 revenues of $2.5 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.