RIO Rio2 Limited New

Rio Alto Mining Limited ("Rio Alto") (TSX VENTURE: RIO)(OTCQX: RIOAF)(BVLAC: RIO)(DBFrankfurt: MS2) is pleased to announce that has closed the first tranche of its previously announced private placement of common shares for gross proceeds of C$12,812,646 (US$12,583,849). At this closing a total of 7,626,575 common shares were sold at the issue price of C$1.68 (US$1.65) per share. Kallpa Securities S.A.B. ("Kallpa") of Lima, Peru acts as Rio Alto's agent for the South American portion of private placement. One or more additional tranches of the private placement are anticipated to be completed this week for aggregate gross proceeds of up to C$20 million.

Of the net proceeds of the private placement, $10 million will be used by Rio Alto to develop La Arena Gold Oxide Project in Peru and for related working capital requirements with the balance to be used by Rio Alto to partially exercise its option under the Option and Earn-in Purchase Agreement dated June 15, 2009 to acquire shares of La Arena S.A., the owner of La Arena Project, and to conduct exploration activities on other areas of La Arena Project.

The common shares issued at this closing of the private placement are subject to a statutory resale restriction period of four months and a day expiring on March 31, 2011. The completion of the private placement is subject to final approval from the TSX Venture Exchange.

In connection with the first tranche of the private placement, Rio Alto will pay Kallpa a cash fee of US$739,000 and also pay finders' fees of C$145,000.

To learn more about Rio Alto Mining Limited, please visit: www.rioaltomining.com or Rio Alto's SEDAR profile at www.sedar.com.

ON BEHALF OF THE BOARD OF RIO ALTO MINING LIMITED

Anthony Hawkshaw, Director and Chief Financial Officer

Forward Looking Statements

Certain statements contained herein constitute forward-looking statements, including the expected amount of and use of proceeds and timing of the closing of a private placement of the Shares and for the development of the La Arena Gold Oxide Project. Rio Alto believes the expectations reflected in these forward looking statements are reasonable but no assurance can be given that these expectations will prove to be correct and such forward-looking statements in this press release should not be unduly relied upon. Closing of the private placement could be delayed if Rio Alto cannot obtain necessary regulatory approvals within anticipated timelines and will not be completed unless certain conditions customary for transactions of this sort are satisfied. Forward looking statements included in this press release are made as of the date of this press release and Rio Alto disclaims any intention or obligation to update or revise any forward-looking statements, whether as a result of new information, future events or otherwise, except as expressly required by applicable securities legislation.

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.

Contacts: Rio Alto Mining Limited Anthony Hawkshaw CFO & Director +1 604 628 1401 or +511 625 9900 tonyh@rioaltomining.com Rio Alto Mining Limited Alejandra Gomez Investor Relations 604.628.1401 866.393.4493 (FAX) alejandrag@rioaltomining.com www.rioaltomining.com