ST. LOUIS (August 20, 2009) - Arch Coal, Inc. (NYSE:ACI) today announced that it has received antitrust clearance from the Federal Trade Commission ("FTC") in connection with the company's pending acquisition of Rio Tinto's Jacobs Ranch mine in the Powder River Basin of Wyoming.

"We are very pleased to be moving one step closer to completing the acquisition of Jacobs Ranch," said Steven F. Leer, Arch's chairman and chief executive officer. "We are now working swiftly to finalize our due diligence on the transaction and to meet all necessary conditions required for closing."

Arch expects the transaction to close within the next six weeks.

"We are confident this acquisition will create significant benefits for our company, our customers and our shareholders," added Leer. "We believe the integration of Jacobs Ranch into our existing Black Thunder mine will further enhance our world-class operations in the PRB, the nation's largest and fastest growing coal supply region."

St. Louis-based Arch Coal is one of the largest U.S. coal producers, with revenues of $3.0 billion in 2008. Through its national network of mines, Arch supplies cleaner-burning, low-sulfur coal to U.S. power producers to fuel roughly 6 percent of the nation's electricity. The company also ships coal to domestic and international steel manufacturers as well as international power producers.

Forward-Looking Statements: This press release contains "forward-looking statements" - that is, statements related to future, not past, events. In this context, forward-looking statements often address our expected future business and financial performance, and often contain words such as "expects," "anticipates," "intends," "plans," "believes," "seeks," or "will." Forward-looking statements by their nature address matters that are, to different degrees, uncertain. For us, particular uncertainties arise from changes in the demand for our coal by the domestic electric generation industry; from legislation and regulations relating to the Clean Air Act and other environmental initiatives; from operational, geological, permit, labor and weather-related factors; from fluctuations in the amount of cash we generate from operations; from future integration of acquired businesses; and from numerous other matters of national, regional and global scale, including those of a political, economic, business, competitive or regulatory nature. These uncertainties may cause our actual future results to be materially different than those expressed in our forward-looking statements. We do not undertake to update our forward-looking statements, whether as a result of new information, future events or otherwise, except as may be required by law. For a description of some of the risks and uncertainties that may affect our future results, you should see the risk factors described from time to time in the reports we file with the Securities and Exchange Commission.