Category: Silver / Gold

Osisko Intersects 258 Metres Averaging 2.13 g/t Gold at Barnat

Osisko Mining Corporation ("Osisko") (TSX: OSK)(FRANKFURT: EWX) is pleased to announce new results from the definition drill program currently under way at South Barnat, a separate gold mineralized zone located approximately 1200 metres northeast of the center of the Canadian Malartic deposit. Significant results include 3.22 g/t Au over 83.5 metres (BA08-3039) and 2.13 g/t Au over 258.5 metres (BA08-3061). Higher grade intercepts include 12.49 g/t Au over 4.0 metres (BA08-3048) and 10.43 g/t Au over 4.9 metres in hole BA08-3049. Results from twenty-two new holes are tabled below:


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Hole No.      Section      From (m)       To (m)    Length (m)      Au g/t
BA08-3035        300E        134.6        146.5          11.9         2.30
And                          212.7        256.6          43.9         1.78
including                    212.7        214.0           1.3        18.05
BA08-3036        250E        141.3        165.0          23.7         1.75
And                          183.0        222.0          39.0         2.26
And                          293.0        300.0           7.0         6.61
BA08-3039        550E         37.5        121.0          83.5         3.22
including                     61.5         63.0           1.5        44.90
And                          149.5        186.5          37.0         0.98
And                          214.0        296.5          82.5         0.76
BA08-3043        150E        251.0        335.7          84.7         1.01
BA08-3045        500E        297.5        317.0          19.5         2.45
BA08-3046        500E        119.5        145.0          25.5         1.96
BA08-3047        550E         89.9        108.5          18.6         1.41
BA08-3048        550E         41.0         70.5          29.5         0.99
And                          100.0        144.0          44.0         2.93
including                    135.5        139.5           4.0        12.49
BA08-3049        550E         30.1         35.0           4.9        10.43
And                           93.5        108.0          14.5         1.93
BA08-3051        100E         73.5        131.5          58.0         2.69
including                     79.5         81.0           1.5        43.70
BA08-3052        050E         96.4        107.9          11.5         4.57
And                          251.5        271.0          19.5         1.14
BA08-3053        050E         94.0        129.5          35.5         0.57
BA08-3054        450E         63.8         79.2          15.4         3.05
And                          177.0        246.6          77.6         1.96
including                    177.0        177.9           0.9        55.60
BA08-3055        450E         65.0        110.5          45.5         1.42
And                          274.0        280.3           6.3         2.91
BA08-3056        500E         83.9        145.5          61.6         1.73
And                          186.6        197.5          10.9         3.49
BA08-3057        500E         22.0         44.5          22.5         1.45
BA08-3058        100E         17.5         51.5         34.00         2.81
And                          149.0        164.0          15.0         3.74
BA08-3059        050E         20.0         56.5          36.5         1.37
BA08-3060        000E         31.0         50.0          19.0         1.50
And                          122.5        141.5          19.0         1.03
BA08-3061        700E        141.0        399.5         258.5         2.13
including                    190.5        193.0           2.5        15.90
including                    378.7        379.7           1.0        19.75
BA08-3062        100E         93.0        158.5          65.5         0.73
BA08-3063        100E         65.5        118.0          52.5         2.01
including                     98.0         99.0           1.0        22.40
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Drill hole BA08-3041 was lost in a fault gouge. Drill holes BA08-3044 and BA08-3050 penetrated historic mine workings and did not intersect significant mineralization. Drill holes BA08-3046 and BA08-3048 intercepted historic mine workings and did not reach the intended target depths. Drill hole BA08-3061 was a steeply inclined hole (83 degrees) designed to test the vertical extent of the mineralized system on section 700E. Assays for drill hole BA08-3061 between 0 and 103 metres are pending. Assay results from further holes at South Barnat are also pending.

The definition drill program is focused on an 850 metre-long grid oriented northwest-southeast with drill sections spaced 50 metres apart. All holes on this grid are inclined 45 to 75 degrees to the northeast or southwest. True widths of the mineralized intersections reported above are 40 to 70 percent of the drilled intersections.

Drilling to date suggests that the minimum strike length of the South Barnat Zone is 850 metres with a true width between 20 and 160 metres. The mineralized zone is open along strike to the southeast, where it merges with the old East Malartic Mine. It extends to a minimum depth of 250 metres in the southeastern portion, where the system is still open at depth. Drill hole BA08-3061 suggests the system may extend as deep as 400 metres below surface. Estimated depth in the northwestern third of the deposit is 130 to 200 metres.

Mineralization in the South Barnat Zone is located to the north and south of the old Barnat and East Malartic mine workings, largely along the southern edge of the Cadillac fault. The gold mineralization comprises multiple subvertical, tabular subzones hosted both in silicified greywackes of the Pontiac Group south of the fault contact and in schistose, carbonated and biotitic ultramafic rocks north of the fault contact. Porphyry dykes on both sides of the fault contain disseminated mineralization as well as late quartz veins containing visible gold. Gold mineralization in the South Barnat Zone likely extends to the east along the north and south walls of the past-producing East Malartic mine.

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 weighted averages were calculated using a minimum of 0.50 g/t Au over successive maximum intervals of 20 metres with no upper cut-off of individual assays. Intersected drifts or lost core within mineralized intersections were incorporated as blank intervals.

Osisko Mining Corp. is currently evaluating the Canadian Malartic gold deposit and adjacent areas for a large-scale open pit, bulk-tonnage mining operation. The Company is well-funded with approximately $145 million on hand and is carrying out an aggressive definition drilling and exploration campaign. An updated NI 43-101 compliant, Measured and Indicated resource estimate on the main Canadian Malartic gold deposit was released on September 8, 2008 and will be filed on SEDAR by mid-October. This updated resource estimate did not include the South Barnat Zone nor any other mineralized zone located outside the main deposit that is currently being evaluated by Osisko.

Mr. Robert Wares, P. Geo. and Executive Vice-President of Osisko, is the Qualified Person responsible for the technical information reported in this news release.

Contacts: Osisko Mining Corporation John Burzynski Vice-President Corporate Development 514-735-7131 www.osisko.com Daniel Boase Investor Relations 416-742-5600 Toll Free: 1-866-580-8891

SOURCE: Osisko Mining Corporation

http://www.osisko.com