Osisko Mining Corporation
TSX : OSK
FRANKFURT : EWX

Osisko Mining Corporation
Clifton Star Resources Inc.
TSX VENTURE : CFO
FRANKFURT : C3T

Clifton Star Resources Inc.

June 17, 2010 10:22 ET

Osisko and Clifton Star Report 4.19 G/T Au Over 27.5 Metres at Duparquet

MONTREAL, QUEBEC--(Marketwire - June 17, 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 twenty-two additional holes from the 2010 drill program and extended core sampling program at the Duparquet Project, located in the Abitibi region of Quebec. Drilling and extended sampling on selected holes are focused on three properties: Beattie, Donchester (eastern extension of Beattie) and Duquesne. The current Phase I drill program comprises 65,000 metres of drilling on the Beattie property (of the overall 2010 Duparquet Project drilling campaign planned for 120,000 metres). To date approximately 52,800 metres from Phase I have been completed as 148 holes. New drilling is planned to focus on the Donchester Property. The property-wide drill program is progressing on schedule with 10 drills currently on site. Additional results are expected to be received and released on a regular basis as they become available from the lab.

Significant new intersections from the new drill holes listed below (from the Beattie property) include 27.5 metres averaging 4.19 g/t Au (BD10-115), and 58.2 metres averaging 1.12 g/t Au (BD10-138). Assay results are summarized in the table below:

Beattie-Donchester Properties

  Hole No. Section Az./dip From (m) To (m) Length Au g/t Au g/t
          (m) (uncut) (cut)
BD10-115 630500E N/60 281.5 309.0 27.5 4.16  
               
BD10-119 631300E N/60 365.0 377.1 12.1 4.46  
including     372.6 374.0 1.4 22.50  
               
BD10-122 631300E N/60 57.6 64.0 6.4 2.25  
And     436.5 457.5 21.0 0.66  
               
BD10-123 630900E N/60 56.0 86.0 30.0 1.16  
               
BD10-125 630000E N/60 45.0 56.3 11.3 1.70  
               
BD10-126 630000E N/44 40.3 45.4 5.1 1.78  
And     86.9 104.3 17.4 1.64  
               
BD10-129 631300E N/60 116.0 128.5 12.5 1.31  
And     340.4 348.5 8.1 0.96  
               
BD10-130 631300E N/58 173.0 206.0 33.0 1.71  
including     204.5 206.0 1.5 24.00  
And     275.5 281.5 6.0 2.66  
Hole No. Section Az./dip From (m) To (m) Length Au g/t Au g/t
          (m) (uncut) (cut)
BD10-131 631300E N/60 5.5 35.0 29.5 1.19  
And     117.9 136.0 18.1 2.58  
including     132.9 134.3 1.4 12.85  
And     397.5 431.4 33.9 0.64  
               
BD10-134 630900E N/60 162.0 196.5 34.5 1.25  
               
BD10-136 630600E N/60 210.4 227.0 16.6 1.80  
               
BD10-137 630000E N/60 33.0 53.5 20.5 2.09  
               
BD10-138 630700E N/60 317.0 375.2 58.2 1.12  
               

Drill hole BD10-127 intersected underground mine workings and did not reach its target depth. Holes BD10-120 and BD10-121 were skipped, and holes BD10-124, BD10-127 and BD10-128 did not intersect significant mineralization. Results for holes BD10-132, -133 and -135 are pending.

Duquesne Property

Hole No. Section Zone From (m) To (m) Length (m) Au g/t
DQ10-15* 642050E Nipissing 114.5 117.0 2.5 5.40
             
DQ10-16 642178E Nipissing 47.0 52.5 5.5 1.52
             
DQ10-25 642150E Nipissing 270.0 271.5 1.5 9.81
             
DQ10-26 642225E Nipissing 33.0 42.0 9.0 1.37
And     142.5 144.0 1.5 28.30
             
DQ10-27 642250E Nipissing 84.2 90.6 6.4 1.44
             
DQ10-28 642285E Nipissing 43.5 51.0 7.5 1.71
             
DQ10-29 642286E Nipissing 142.5 147.0 4.5 3.54
             
* Restated from previous press release.

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, and Mr. Fred Archibald, P. Geo. and VP of Exploration for Clifton Star Resources Inc., are the Qualified Persons who have reviewed this news release and are 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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