Stillwater Mining Company Announces Offering of Convertible Senior Notes

BILLINGS, MT–(Marketwire – October 11, 2012) – STILLWATER MINING COMPANY (NYSE: SWC) (TSX: SWC.U) (the “Company”) announced today that it intends to offer $300 million aggregate principal amount of convertible senior notes due 2032 (the “notes”), subject to market and other conditions. The Company expects to grant the underwriters of the notes a 30-day over-allotment option to purchase up to an additional $45 million aggregate principal amount of the notes (subject to certain limitations), solely to cover over-allotments.

The notes will pay interest semi-annually and will be convertible, under certain circumstances and during certain periods, into cash, shares of the Company’s common stock or a combination thereof, at the Company’s election, based on a conversion rate to be determined. If the price of the Company’s common stock exceeds the base conversion price during specified periods applicable to conversion, holders will receive additional shares of the Company’s common stock upon conversion, as determined based on the incremental share factor. The interest rate, base conversion rate, base conversion price, incremental share factor and other terms of the notes will be determined at the time of pricing of the offering.

The Company intends to use the net proceeds from the offering to repay amounts that may come due under the Company’s outstanding 1.875% convertible debentures in March 2013, and any additional proceeds may be used for general corporate purposes.

Credit Suisse Securities (USA) LLC and Wells Fargo Securities, LLC are acting as joint book-running managers for the offering, which is being made pursuant to an effective shelf registration statement (including a prospectus and related preliminary prospectus supplement for the offering).

Before you invest, you should read the base prospectus in such shelf registration statement, the related preliminary prospectus supplement for the offering and other documents the Company has filed with the Securities and Exchange Commission (the “SEC”) for more complete information about the Company and the offering. The offering will be made only by means of a prospectus supplement and accompanying base prospectus. When available, copies of the prospectus supplement and accompanying base prospectus relating to the offering may be obtained by contacting Credit Suisse Securities (USA) LLC at One Madison Avenue, New York, NY 10010, Attn: Prospectus Department, e-mail: newyork.prospectus@credit-suisse.com or at (800) 221-1037 or Wells Fargo Securities, LLC at 375 Park Avenue, New York, NY 10152, Attn: Equity Syndicate Department, e-mail: cmclientsupport@wellsfargo.com or at (800) 326-5897. Alternatively, investors may get these documents for free by visiting EDGAR on the SEC website at http://www.sec.gov/.

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

About Stillwater

Stillwater Mining Company is the only U.S. producer of palladium and platinum and is the largest primary producer of platinum group metals outside of South Africa and the Russian Federation. The Company’s shares are traded on the New York Stock Exchange under the symbol SWC and on the Toronto Stock Exchange under the symbol SWC.U.