Osisko Mining Corporation
TSX : OSK
FRANKFURT : EWX

Osisko Mining Corporation

July 05, 2005 08:00 ET

Osisko Exploration Ltd.: Gold Mineralization Extended at Depth at Canadian Malartic

MONTREAL, QUEBEC--(CCNMatthews - July 5, 2005) - Osisko Exploration Ltd. (TSX VENTURE:OSK)(Deutsche Boerse:EWX) is pleased to announce the results from the first three holes of the Phase Two drill program on its 100%-owned Canadian Malartic gold property, located in the Abitibi region of Quebec. The current program is testing grade and distribution of gold mineralization in the deposit to depths below those that were previously drilled (up to 300 meters depth) in order to confirm the potential for a large bulk-tonnage gold deposit. Results of the first three holes of this program are very encouraging and are tabled below:



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Hole No. From (m) To (m) Length (m) Au g/t

CM05-661 1.4 50.3 48.9 1.29
and 129.0 322.0 193.0 1.22

CM05-664 33.1 50.1 17.0 1.28
and 133.6 258.6 125.0 0.82

CM05-665 29.6 288.6 259.0 1.00
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All holes were drilled vertically at the eastern limit of the F zone, and intersected sediment-hosted mineralization followed by lower grade, porphyry-hosted mineralization at depth. Average gold grades in each rock type are as follows (excluding shallow, sediment-hosted mineralized zones in holes CM05-661 and CM05-664):

Hole CM05-661 (previously reported and deepened in the current drill program) intersected, from a depth of 129.0 meters, 1.93 g/t Au over 102.5 meters in sediments followed by 0.42 g/t Au over 90.5 meters in porphyry;

Hole CM05-664 intersected, from a depth of 133.6 meters, 1.14 g/t Au over 66.4 meters in sediments followed by 0.45 g/t Au over 58.6 meters in porphyry;

Hole CM05-665 intersected, from a depth of 29.0 meters, 1.29 g/t Au over 165.0 meters in sediments followed by 0.49 g/t Au over 94.0 meters in porphyry.

The data now confirm that the F zone is but the near-surface, western extremity of a much larger, contiguous mineralized zone extending at depth. The auriferous zone forms a shell of disseminated mineralization in the upper portion of a diorite porphyry intrusion as well as the overlying altered sediments. Management believes, based on compilation of previous drill data, that the mineralized zone at Canadian Malartic has a strike length of 1200 meters, a width of 350 to 400 meters and a true thickness between 80 meters and as much as 250 meters, as has now been demonstrated by hole CM05-665.

The Phase Two drill program will continue throughout the summer and further assay results will be released as they are received. All reported assays were done by standard 50 g fire assaying-AA finish at ALS Chemex laboratories in Val d'Or, Quebec. Mr. Robert Wares, P. Geo. And President of Osisko, is the Qualified Person responsible for the preparation of this news release.

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