MONTREAL, QUEBEC–(Marketwired – March 19, 2014) – Osisko Mining Corporation (the “Company” or “Osisko”) (TSX:OSK)(FRANKFURT:EWX) is pleased to report February cash costs per ounce⁽¹⁾ of US$555 (C$613) at its flagship Canadian Malartic mine. Osisko previously announced production of 46,154 ounces of gold with record average daily gold production of 1,648 ounces for the month of February (see Osisko press release dated March 5, 2014).

Statistics for the month of February 2014 are presented below:

• Record average daily gold production of 1,648 ounces
• Production of 46,154 ounces for the month of February
• Monthly mill throughput of 1,492,582 tonnes
• Average daily throughput of 53,307 tonnes per operating day
• Average grade milled of 1.10 g/t Au
• Average recovery of 87.7%

Sean Roosen, President and CEO of Osisko stated: “Canadian Malartic is continuing to prove its strength and its position as a premium world-class mine. Our team is achieving new production records while reducing overall costs. The start of 2014 has seen strong production and decreasing cash costs per ounce⁽¹⁾ as our team continues to concentrate on the optimization of the mine and mill. Results in January and February continue to underscore the tremendous value to all shareholders of our strong free cash flowing asset. I would like to remind shareholders of the unanimous recommendation of Osisko’s Board of Directors to shareholders that you reject Goldcorp’s inadequate hostile offer, and not to tender your shares to their bid.”

Reject the Inadequate Goldcorp Offer

As previously disclosed, the Osisko Board of Directors has unanimously recommended that Osisko shareholders reject the hostile take-over bid initiated by Goldcorp and not tender their Osisko shares to the Goldcorp offer. The Osisko Board determined that the Goldcorp offer fails to adequately compensate Osisko shareholders for, among others things, the strategic value of Osisko’s world-class asset base, the significant upside potential of Osisko’s Canadian Malartic Mine, or the increased risk inherent in Goldcorp common shares. The full basis for the Osisko Board’s recommendation is available in a Directors’ Circular, a copy of which is available online at www.osisko.com.

Shareholders who have questions or who may have already tendered their shares to the Goldcorp Offer and wish to withdraw them, may do so by contacting our Information Agent, Laurel Hill Advisory Group at:

North American Toll Free: 1-877-452-7184

Banks, Brokers or collect calls: 416-304-2011

Email: [email protected]

About Osisko Mining Corporation

Osisko Mining Corporation operates the Canadian Malartic Gold Mine in Malartic, Québec and is pursuing exploration on a number of properties in Ontario and Mexico.

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, the optimization and stabilization of the mine and mill activities, the decrease of costs and increase of gold production, and Osisko’s view on the quality and the potential of its Canadian Malartic asset and on Goldcorp common shares. Although Osisko believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, 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 and construction personnel, Osisko’s limited experience with production and mining operations, uninsured risks, regulatory framework and 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.