Rio Alto Mining Limited
TSX VENTURE : RIO
FRANKFURT : MS2
BVLAC : RIO

Rio Alto Mining Limited

March 22, 2010 12:08 ET

Rio Alto Mining Limited: TSX Venture Exchange Approves Application to Extend the Expiry Date of Outstanding Warrants

CALGARY, ALBERTA--(Marketwire - March 22, 2010) - Rio Alto Mining Limited ("Rio Alto") (TSX VENTURE:RIO)(BVLAC:RIO)(DBFrankfurt:MS2) announces that further to its news release issued on March 17, 2010, the TSX Venture Exchange has approved Rio Alto's application to extend the expiry date of 6,420,750 warrants (the "Warrants") with a exercise price of $1.30 per common share to December 31, 2010. The extension of the term of the Warrants is effective immediately. All other terms of the Warrants remain the same. For further information on the original issuance of the Warrants and a subsequent amendment, please refer to the press releases of Rio Alto dated July 3, 2007 and January 6, 2009 filed on SEDAR.

Warrant holders are advised that replacement Warrant certificates will not be issued and that the original Warrant certificates must be presented to Rio Alto in order to effect the exercise or transfer of such Warrants.

Rio Alto Mining Limited is focused on developing the La Arena Gold Oxide Project by the end of 2010 to become the next company in Peru to bring a gold project into production and to use cash flow from production to further develop its assets in Peru and Mexico.

This news release may contain certain forward-looking information. All statements included herein, other than statements of historical fact, is forward-looking information and such information involves various risks and uncertainties. There can be no assurance that such information will prove to be accurate, and actual results and future events could differ materially from those anticipated in such information. A description of assumptions used to develop such forward-looking information and a description of risk factors that may cause actual results to differ materially from forward-looking information can be found in Rio Alto's disclosure documents on the SEDAR website at www.sedar.com. Rio Alto does not undertake to update any forward-looking information except in accordance with applicable securities laws.

To learn more about Rio Alto Mining Limited, please visit: www.rioaltomining.com

ON BEHALF OF THE BOARD OF
RIO ALTO MINING LIMITED

Feisal Somji, B.Sc., MBA
President and Chief Executive Officer

Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts the responsibility for the adequacy or accuracy of this release.

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