May 14, 2012

OSISKO PROVIDES UPDATE ON CANADIAN MALARTIC

(Montreal, May 14, 2012) Osisko Mining Corporation (the "Company" or "Osisko") (OSK: TSX, EWX: Deutsche Boerse) herein provides an update from the preliminary assessment of fire damage incurred last week at the Canadian Malartic Mill and preliminary time estimates of the recommencement of production.

Civil engineering inspections have been conducted on the mill floor and roof areas affected by the fire, and safety concerns in the area of the Number 4 cyclone bank have been addressed. Clean-up and repair work has commenced.

A 600 tonne capacity mobile crane has been brought to site, and the Number 4 cyclone bank is being removed from the building and should be expedited tonight for refurbishing. Combined with the existing inventory of spare parts at the mine and work being carried out by suppliers, Osisko believes the Number 4 cyclone bank can be rehabilitated to working state in the near term.

SAG mill, ball mill and crusher wear steel is being replaced concurrently with work on the cyclone, work which was previously scheduled for the mid-May maintenance shut down but is proceeding ahead of schedule because of the fire-related shut down.

Osisko currently believes production will be able to resume in the near term using the three undamaged cyclone banks at a reduced throughput. Exact timing of the restart of production should be available later this week, as well as an estimate on the delay time needed to re-establish service of the Number 4 cyclone.

Insurance company representatives have been to site and the evaluation and claim process is following normal course. Initial advance payment on the claim is scheduled to be received within 10 to 15 days.

Mining activity in the pit has continued uninterrupted, and was not affected by last week's fire.

Osisko would like to reassure stakeholders that all steps and measures are being taken to return Canadian Malartic to production in a safe and timely manner, and that the company is using this unscheduled downtime to best advantage while efforts to reestablish production continue.

Secondary Crusher and Pebble Crusher

It has also been confirmed that the adjustment ring for the second FLSmidth XL2000 cone crusher has been safely loaded in Brazil and is now preparing for shipment on a dedicated vessel destined for Trois-Rivieres, Quebec where it will undergo three weeks of machining and tooling on arrival. The other main components of the second FLSmidth XL2000 cone crusher are currently in transit via rail from Halifax to Malartic.

The components of the new pebble crusher purchased from FLSmidth (noted in last Friday's press release) will be shipped this week via land transport from Northern United States to Malartic.

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 Project in Northern Ontario.

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, consequence of this incident on operations at Canadian Malartic operations. Although Osisko believes the expectations expressed in such forward-looking statements are based on reasonable assumptions, including, without limitation, that all technical, economical and financial conditions will be met in order to warrant further development of its Hammond Reef project and that the diligent ongoing optimizing of its operations at the Canadian Malartic mine including the installation of the secondary crushing circuit will be achieved and will, accordingly, improve its operating performance, 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.

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