Attached please find a press release on: Rio Tinto announced today that its wholly owned subsidiary, Cloud Peak Energy Inc. (Cloud Peak Energy), has filed a new 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 Rio Tinto Energy America’s (RTEA’s) western U.S. coal assets, is a major producer of coal in the U.S. and in the Powder River Basin, operating two of the five largest coal mines in the region.