Wheaton Precious Metals (WPM)

[NYBob]

Silverstone Completes Arrangement With Silver Wheaton

VANCOUVER, BRITISH COLUMBIA -- (Marketwire) -- 05/21/09 -- Silverstone Resources Corp. ("Silverstone") (TSX VENTURE: SST) is pleased to announce the closing of the previously announced acquisition of Silverstone by Silver Wheaton Corp. ("Silver Wheaton") by way of plan of arrangement under the Business Corporations Act (British Columbia) (the "Arrangement"). The Arrangement was approved by the shareholders of Silverstone on May 19, 2009 and the Supreme Court of British Columbia on May 20, 2009.

Pursuant to the Arrangement, Silver Wheaton acquired all of the issued and outstanding common shares of Silverstone at an exchange ratio of 0.185 of a Silver Wheaton common share for each Silverstone common share. Silverstone's shares will be delisted from the TSX Venture Exchange effective at the close of trading on or about May 25, 2009. In connection with the Arrangement, each of the directors and officers of Silverstone resigned effective May 21, 2009.

Silverstone, through its transfer agent, has mailed instructions to Silverstone's shareholders informing them of the procedure to tender their shares for the share consideration payable under the Arrangement. A copy of the letter of transmittal has also been filed under Silverstone's profile on SEDAR at www.sedar.com.

Further details regarding the terms of the Arrangement are set out in Silverstone's management information circular dated April 16, 2009, which is available on SEDAR at the address above.

Contacts:

Silver Wheaton Corp.

Brad Kopp

Director, Investor Relations

1-800-380-8687

Email: [e-mail]

Website: www.silverwheaton.com