Rio Tinto Announces the Filing of a Registration Statement by Cloud Peak Energy Inc. for a Proposed Initial Public Offering

Friday, August 8th 2008

Rio Tinto announced today that its wholly owned subsidiary, Cloud Peak Energy Inc., has filed a registration statement on Form S-1 with the United States Securities and Exchange Commission (SEC) in connection with Cloud Peak Energy’s proposed initial public offering (IPO) of its common stock. Cloud Peak Energy, comprised of most of the North American coal assets of Rio Tinto Energy America, is the second largest producer of coal in the U.S. and in the Powder River Basin, operating three of the five largest coal mines in the region.

Rio Tinto expects to make a final decision on whether to pursue a listing of the shares of Cloud Peak Energy or to pursue another form of divestment once these options have been more fully explored.

Rio Tinto is a leading international mining group headquartered in the UK, combining Rio Tinto plc, a London listed company, and Rio Tinto Limited, which is listed on the Australian Securities Exchange.

Rio Tinto’s business is finding, mining, and processing mineral resources. Major products are aluminium, copper, diamonds, energy (coal and uranium), gold, industrial minerals (borax, titanium dioxide, salt, talc) and iron ore. Activities span the world but are strongly represented in Australia and North America with significant businesses in South America, Asia, Europe and southern Africa.