Osisko Reports Record Monthly Throughput at Canadian Malartic

Production of 36,440 Ounces of Gold in Month of October

MONTREAL, QUEBEC -- (Marketwire) -- 11/12/12 -- Osisko Mining Corporation (the "Company" or "Osisko") (TSX: OSK) (FRANKFURT: EWX) is pleased to report that it has achieved a record monthly throughput at its flagship Canadian Malartic Mine in the month of October. The mill processed a new record of 1,530,195 tonnes in the month of October, producing 36,440 ounces of gold in the month. Production statistics for October are listed below:

- Monthly gold production of 36,440 ounces
- Record monthly mill throughput of 1,530,195 tonnes
- Record average daily throughput (based on 31 days of operation) of 49,361 tonnes per day
- Average grade milled of 0.833 g/t Au
- Average recovery of 88.9%


November Throughput Preview

Crushing and milling throughputs have continued to improve towards and beyond design rates in the early part of November. Canadian Malartic's nameplate throughput target of 55,000 tonnes per day was consistently exceeded over the first four days of November, with another new record one-day processing rate of 58,476 tonnes being achieved on November 4th. Average mill throughput in the first eight days of the current month averaged 52,853 tonnes per day. Installation of the second pebble crusher is currently planned for the next scheduled mill maintenance shut-down in December or January.


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.

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 continued improvement of milling throughputs and the timely installation of the second pebble crusher at the Canadian Malartic Mine. 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 continue to improve milling throughputs at Canadian Malartic and allow for timely installation of the additional pebble crusher, 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, results of exploration and development activities, 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.



Contact

John Burzynski
Vice-President Corporate Development
(416) 363-8653

Sylvie Prud'homme
Director of Investor Relations
(514) 735-7131
Toll Free: 1-888-674-7563
www.osisko.com