Osisko Mining Corporation
TSX : OSK
FRANKFURT : EWX

Osisko Mining Corporation
Clifton Star Resources Inc.
TSX VENTURE : CFO

Clifton Star Resources Inc.

December 11, 2009 10:31 ET

Osisko and Clifton Star Complete Joint Venture Agreement on Duparquet Project

MONTREAL, QUEBEC--(Marketwire - Dec. 11, 2009) - Osisko Mining Corporation ("Osisko") (TSX:OSK)(FRANKFURT:EWX) and Clifton Star Resources ("Clifton") (TSX VENTURE:CFO)(FRANKFURT:C3T) are pleased to announce that they have finalized an Agreement to enter into a Joint Venture on the Duparquet Project announced on November 16, 2009.

Under the terms of the Agreement, Osisko will earn a 50% interest in the Joint Venture by investing $70 million over a 4-year period, including a firm commitment of $15 million in 2010. Osisko will act as operator of the Joint Venture during the earn-in period and thereafter as long as Osisko holds a minimum 50% interest in the Joint Venture.

Osisko has also agreed to advance up to $31 million to Clifton to fund its option payments to the underlying property vendors. These advances are repayable within 24 months after disbursements, bear an annual interest rate of 5%, and are unsecured.

Osisko will also make an unsecured loan to Clifton for a principal amount of $6 million on or before January 1, 2010 for general corporate purposes. This loan will also bear interest at the rate of 5% per annum, have a term of 12 months from the date of advance, and will be evidenced by a promissory note. Clifton, at its sole option, may elect at any time to convert the entire amount of principal and interest owing under such loan into common shares of Clifton at a conversion price per share of $3.12, provided such conversion is subject to prior approval of applicable regulatory agencies and stock exchanges. The promissory note shall provide for the customary anti-dilution and conversion rights protection for the lender.

The coming into force of the Agreement remains subject to the approval of the stock exchange.

Mr. Sean Roosen, President and Chief Executive Officer of Osisko commented on the transaction: "We look forward to initiating an intensive exploration program on the Duparquet Project. We believe the project offers excellent potential for the definition of additional porphyry-hosted gold resources, and we are confident in our ability to build on the previously identified resources."

Mr. Harry Miller, President and Chief Executive Officer of Clifton Star commented: "We are pleased to conclude this Joint Venture Agreement, and are excited about getting Osisko's exploration and technical teams at Duparquet. Shareholders of both Clifton Star and Osisko should be in for an exciting year ahead."

About the Duparquet Project

The Duparquet Project is located in the Abitibi region of Quebec, approximately 90 km northwest of Osisko's Canadian Malartic Project. It comprises two large property blocks that cover approximately 8 kilometres of strike length along the prolific Porcupine Destor Fault Zone, which has historically produced over 80 million ounces of gold. The properties host former producing underground gold mines (including the Beattie, Donchester and Duquesne mines which, collectively, produced over 1.5 million ounces of gold from 1933 - 1991) and two deposits with known gold resources (Central Duparquet and Dumico).

Clifton recently filed a NI 43-101 compliant report based on new drilling at Beattie and Donchester which outlines significant gold resources on the property (see Clifton press release dated September 8, 2009).

About Clifton Star

Clifton Star Resources, Inc. is a junior gold exploration company focused on developing its Duparquet and Destor Township gold properties located in northwestern Quebec. Historically, Quebec ranks as one of the most supportive mining jurisdictions in the world.

About Osisko

Osisko Mining Corporation is currently developing the Canadian Malartic gold deposit and adjacent mineralized zones into a large-scale open pit, bulk-tonnage mining operation. The Company is well-funded with $825 M in cash resources and is carrying out an aggressive mine development, reserve definition and exploration campaign. The Canadian Malartic deposit currently represents one the biggest gold reserves in Canada for a single deposit, and is still growing through ongoing drilling on new mineralized zones. Current reserves for the Canadian Malartic property are 6.28 million ounces with 183.3 Mt @ 1.07 g/t Au (proven reserves: 5.16 Mt @ 1.14 g/t Au, probable reserves: 178.2 Mt @ 1.06 g/t Au).

Cautionary Notes Concerning Estimates of Mineral Resources
This news release uses the terms measured, indicated and inferred resources as a relative measure of the level of confidence in the resource estimate. Readers are cautioned that mineral resources are not economic mineral reserves and that the economic viability of resources that are not mineral reserves has not been demonstrated. In addition, inferred resources are considered too geologically speculative to have any economic considerations applied to them. It cannot be assumed that all or any part of an inferred mineral resource will ever be upgraded to a higher category. Under Canadian rules, estimates of inferred mineral resources may not form the basis of feasibility or pre-feasibility studies or economic studies except for Preliminary Assessment as defined under NI 43-101. Readers are cautioned not to assume that that further work on the stated resources will lead to mineral reserves that can be mined economically.

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 the Corporation 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. Although the Corporation 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 put the Canadian Malartic Project into commercial production, 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 mill production personnel, results of exploration and development activities, the Corporation'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 the Corporation's most recent Annual Information Form filed on SEDAR, which also provides additional general assumptions in connection with these statements. The Corporation cautions that the foregoing list of important factors is not exhaustive. Investors and others who base themselves on the Corporation's forward-looking statements should carefully consider the above factors as well as the uncertainties they represent and the risk they entail. The Corporation 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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