Rio Tinto announces the filing of a Registration Statement by Cloud Peak Energy Inc. for a proposed Initial Public Offering

Rio Tinto announces the filing of a Registration Statement by Cloud Peak Energy Inc. for a proposed Initial Public Offering

Rio Tinto announces the filing of a Registration Statement by Cloud Peak Energy Inc. for a proposed Initial Public Offering

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.

The joint book-running managers for the offering are Credit Suisse Securities (USA) LLC,
Morgan Stanley & Co. Incorporated and RBC Capital Markets Corporation.

The offering of common stock will be made only by means of a prospectus. When
available, a copy of the preliminary prospectus relating to this offering may be obtained
from Credit Suisse Prospectus Department, One Madison Avenue, New York, NY 10010,
phone: (800) 221-1037; Morgan Stanley & Co. Incorporated, Prospectus Department,
180 Varick Street 2/F, New York, NY 10014, phone: (866) 718-1649; or RBC Capital
Markets Corporation, Equity Syndicate, Three World Financial Center, 200 Vesey Street,
8th Floor, New York, NY 10281-8098, phone: (212) 428-6670.

A registration statement relating to these securities has been filed with the SEC but has
not yet become effective. These securities may not be sold, nor may offers to buy be
accepted, prior to the time the registration statement becomes effective.

This news release shall not constitute an offer to sell or the solicitation of an offer to buy,
nor shall there be any sales of these securities in any state in which such offer,
solicitation or sale would be unlawful prior to registration or qualification under the
securities laws of any such state or jurisdiction.