Osisko Previews Q1 2013 Canadian Malartic Operating Results

MONTREAL, QUEBEC -- (Marketwired) -- 04/09/13 -- Osisko Mining Corporation (the "Company" or "Osisko") (TSX: OSK)(FRANKFURT: EWX) today reports a preview of Canadian Malartic operational results for the quarter ended March 31, 2013.

Q1 Highlights

--  Record gold production of 106,047 ounces

--  Record total tonnage processed of 4,234,001 t

--  Record average daily tonnage processed of 47,044 tpd (based on 90
    calendar days)

--  Record average daily tonnage processed of 48,389 tpd (based on 87.5
    operational days)

--  Record one-month gold production of 42,521 ounces (March)

--  Record one-month tonnage processed of 1,594,608 t (March)

--  Record one-month average tonnage processed of 51,439 tpd (March,
    calendar day)

--  Average recovery of 88 percent

--  Average grade milled of 0.885 g/t Au

About Osisko Mining Corporation

Osisko Mining Corporation operates the Canadian Malartic Gold Mine in Malartic, Quebec and is pursuing exploration on a number of properties, including the Hammond Reef Gold and Upper Beaver projects in Northern Ontario.

Mr. Luc Lessard, Eng., Senior Vice-President and Chief Operating Officer of Osisko, is the Qualified Person who has reviewed this news release and is responsible for the technical information reported herein, including verification of the data disclosed.

Forward-Looking Statements

Certain statements contained in this press release may be deemed "forward-looking statements". All statements in this release, other than statements of historical fact, that address events or developments that Osisko expects to occur, are forward looking statements. Forward looking statements are statements that are not historical facts and are generally, but not always, identified by the words "expects", "plans", "anticipates", "believes", "intends", "estimates", "projects", "potential", "scheduled" and similar expressions, or that events or conditions "will", "would", "may", "could" or "should" occur including, without limitation, continued exploration and development of the Upper Beaver and Hammond Reef projects. Although Osisko believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, including, without limitation, that all technical, economical, regulatory and financial conditions will be met in order to continue exploration and development of the Hammond Reef and Upper Beaver projects, such statements are not guarantees of future performance and actual results may differ materially from those in forward looking statements. Factors that could cause the actual results to differ materially from those in forward-looking statements include gold prices, access to skilled consultants, mining development personnel, results of exploration and development activities, Osisko's limited experience with production and development stage mining operations, uninsured risks, regulatory changes, defects in title, availability of personnel, materials and equipment, timeliness of government approvals, actual performance of facilities, equipment and processes relative to specifications and expectations, unanticipated environmental impacts on operations market prices, continued availability of capital and financing and general economic, market or business conditions. These factors are discussed in greater detail in Osisko's most recent Annual Information Form and in the most recent Management Discussion and Analysis filed on SEDAR, which also provide additional general assumptions in connection with these statements. Osisko cautions that the foregoing list of important factors is not exhaustive. Investors and others who base themselves on forward-looking statements should carefully consider the above factors as well as the uncertainties they represent and the risk they entail. Osisko believes that the expectations reflected in those forward-looking statements are reasonable, but no assurance can be given that these expectations will prove to be correct and such forward-looking statements included in this press release should not be unduly relied upon. These statements speak only as of the date of this press release.

Contacts:

John Burzynski

Vice-President Corporate Development

(416) 363-8653
www.osisko.com


Sylvie Prud'homme

Director of Investor Relations

(514) 735-7131

Toll Free: 1-888-674-7563