Osisko Mining Corporation

Osisko Mining Corporation
Clifton Star Resources Inc.

Clifton Star Resources Inc.

September 13, 2010 14:59 ET

Osisko and Clifton Star Intersect 42 Metres Averaging 3.78 g/t Au at Duparquet

MONTREAL, QUEBEC--(Marketwire - Sept. 13, 2010) - Osisko Mining Corporation ("Osisko") (TSX:OSK)(FRANKFURT:EWX) and Clifton Star Resources Inc ("Clifton") (TSX VENTURE:CFO)(FRANKFURT:C3T) are pleased to announce results from thirty-seven additional holes from the 2010 drill program at the Duparquet Project, located in the Abitibi region of Quebec. Significant intersections from the new drill holes from the Beattie property include 42.0 metres averaging 3.78 g/t Au (BD10-228), 35.9 metres averaging 2.11 g/t Au (BD10-242) and 70.5 metres averaging 1.32 g/t Au (BD10-245). Assay results are summarized in the table below.

Drilling is focused on three properties: Beattie, Donchester (eastern extension of Beattie) and Duquesne for an overall 2010 drilling campaign of 122,000 metres. The current Phase I drill program comprises 67,500 metres of drilling on the Beattie property, currently 98 percent complete with 202 out of 206 holes. A Phase Two drilling program of 20,000 metres is 100 percent complete on the Duquesne property, and a Phase Three program of 33,000 metres is 80 percent complete on the Donchester Property. The property-wide drill program is progressing on schedule with 5 drills currently on site.

Beattie Property

Hole No. Section Az./dip From (m) To (m) Length (m) Au g/t
BD10-222 631000E N/60 8.0 30.5 22.5 1.35
And     162.3 171.1 8.8 2.31
BD10-224 630700E S/60 89.0 107.0 18.0 2.06
And     155.9 163.5 7.6 1.82
BD10-226 630600E S/45 52.7 63.5 10.8 1.85
And     120.3 127.7 7.4 2.13
BD10-228 629900E N/60 27.0 69.0 42.0 3.78
including     58.5 61.5 3.0 15.95
BD10-229 629900E S/73 72.3 83.0 10.7 1.26
BD10-230 630300E S/65 141.0 172.5 31.5 0.75
BD10-231 630300E S/51 237.5 257.0 19.5 1.29
BD10-232 631100E N/60 310.0 313.7 3.7 5.27
BD10-233 631100E N/68 93.5 98.1 4.6 4.40
And     223.0 228.8 5.8 1.76
And     301.1 305.8 4.7 3.35
BD10-241 630200E N/60 236.0 246.5 10.5 3.85
BD10-242 630400E N/60 188.0 223.9 35.9 2.11
BD10-244 630500E S/60 349.5 363.0 13.5 1.48
BD10-245 630300E S/60 285.5 356.0 70.5 1.32

Drill holes BD10-221, BD10-223, BD10-225, BD10-227, BD10-235 to BD10-238 and BD10-240 did not intersect significant mineralization. These holes tested the core of the syenite porphyry intrusion, margins to underground stopes, or alternatively surrounding basalts and sediments, all separate from the known mineralized zones. Results for holes D10-169, BD10-186, BD10-188, BD10-194, BD10-210, BD10-234, BD10-239 and BD10-243 are pending.

Duquesne Property

Over the past two months, the drill program at Duquesne has been concentrating on extending the Nipissing Zone as well as the Main Zone to the east of the Duquesne underground workings. Recent drilling results on the Main Zone are as follows:

Hole No. Section Zone From (m) To (m) Length (m) Au g/t
DQ10-47 645200E Main 71.0 72.0 1.0 13.15
DQ10-48 645250E Main 32.9 39.1 6.2 1.35
DQ10-52 645450E Main 27.0 46.5 19.5 4.22
including     33.0 34.5 1.5 21.40
DQ10-53 645500E Main 55.5 57.0 1.5 5.18
DQ10-61 645600E Main 346.5 361.7 15.2 2.60
including     360.0 361.7 1.7 15.20
DQ10-62 645350E Main 123.0 124.0 1.0 9.34
DQ10-63 645850E Main 42.2 48.6 6.4 4.47
DQ10-64 645900E Main 222.0 227.2 5.2 2.01
DQ10-67 645450E Main 381.2 383.0 1.8 5.63
DQ10-68 645400E Main 279.0 284.0 5.0 1.05
DQ10-72 646000E Main 287.4 297.1 9.7 1.65
DQ10-76 645750E Main 96.0 107.0 11.0 5.81
including     98.0 100.0 2.0 17.7

Drill holes DQ10-43, DQ10-45, DQ10-49, DQ10-50, DQ10-51, DQ10-54 to DQ10-60, DQ10-65, DQ10-66, DQ10-69 to DQ10-71, DQ10-74 and DQ10-75 did not intersect significant mineralization. Assays for drill hole DQ10-73 are pending.

Osisko has the right to acquire a 50% interest in the Duparquet project in consideration for (1) total exploration expenditures of $70 million from 2010 to 2013, and (2) extending loans to Clifton to fund option payments on the property of $8.5 million for 24 months and $22.5 million for 36 months. These loans would carry interest at 5% and can be converted into stock at Clifton's choice. Osisko had also extended a $6 million credit line to Clifton, to be drawn prior to January 1, 2010, which was not utilized.

All NQ core assays reported above were obtained by standard 50 g fire assaying-AA finish or gravimetric finish at ALS Chemex laboratories in Val d'Or, Quebec. Reported drill core weighted averages were calculated using a minimum of 0.60 g/t Au over successive maximum intervals of 20 metres with an upper cut-off of 30 g/t Au where indicated. Intersected drifts or lost core within mineralized intersections were incorporated as blank intervals. The true widths are estimated at approximately 50% to 75% of the core lengths reported above.

Osisko follows strict QA-QC protocol measures in keeping with industry standards and regulatory reporting requirements. Mr. Robert Wares, P. Geo. and Executive Vice-President 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 including the sampling, analytical and test data underlying the technical information.

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 and Clifton (collectively the "Parties") expect 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 commencement of commercial production. Although the Parties believe 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 the Duparquet Project, 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, the Parties' 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 Clifton's most recent Management Discussion and Analysis filed on SEDAR, which also provide additional general assumptions in connection with these statements. The Parties caution that the foregoing list of important factors is not exhaustive. Investors and others who base themselves on the Parties' forward-looking statements should carefully consider the above factors as well as the uncertainties they represent and the risk they entail. The Parties believe 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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