Osisko publica resultados de Sta Catarina

The Santa Catarina property includes two adjacent blocks, Carneiro and Braco, covering 1,831 ha located in an area with well developed infrastructure within Santa Catarina State, southern Brazil. Three main gold occurrences were confirmed by the due diligence sampling: Carneiro 1, Italiano and Braco 1. Results obtained from the sampling range from less than 5ppb Au to over 76 g/t Au. A total of 284 samples were collected, 67 samples returning values greater than 1 g/t Au. The latter include 21 samples with values greater than 10 g/t Au (including repeat samples), results of which are listed below:

Sample Number  Showing     Results (g/t Au)   Comments
                        (50g-FA) (50g-FA grav)
---------------------------------------------------------------------
MCA-101       Carneiro    34.02         29.45 5m panel sample
                          16.14         14.18 5m repeat panel sample
                           9.59         10.34 5m repeat panel sample

MCA-140       Carneiro    23.56         24.59 5m chip sample
MCA-145       Carneiro    10.41         11.37 5m panel sample,
                                               hanging wall

MCA-207       Italiano    18.28         20.68 chip sample (boulder)
MCA-236       Italiano    76.56         76.80 chip sample (boulder)
MCA-237       Italiano    48.60         54.93 chip sample (boulder)

MCA-53         Braco 1    19.18         21.16 panel sample
                          24.43         25.14 repeat panel sample
                          17.89         18.63 repeat panel sample

MCA-57         Braco 1    13.56         12.53 panel sample
                          21.75         20.14 repeat panel sample
                          14.59         15.89 repeat panel sample

MCA-62         Braco 1    18.51         17.47 panel sample
                          14.80         18.56 repeat panel sample
                          10.00         10.75 repeat panel sample

MCA-203        Braco 1    21.30         17.26 chip sample (boulder)
MCA-254        Braco 1    27.02         30.00 chip sample (boulder)
MCA-292        Braco 1    57.74         49.31 panel sample
MCA 293        Braco 1    22.79         22.88 panel sample

The principal showing on the Carneiro Block (Carneiro 1) is an E-W striking, shear-hosted quartz-sulfide vein system which outcrops intermittently for approximately 240 meters along the shear zone. The mineralized zone is up to 8 meters in width and averages 1.8 meters in true width. Previous sampling of the widest observed section returned 8m @ 12.0 g/t Au (Osisko press release, January 21, 2004).

Additional positive results were obtained on the Carneiro Block at the Italiano showing, located approximately 2 kilometers west along strike from the Carneiro 1 showing. Paucity of outcrop at Italiano restricted sampling to subcrop and loose boulders. Sampling of boulders of quartz-sulfide veins hosted by sericitized granite returned values of up to 76.80 g/t Au (see table above).

The Braco 1 showing is located approximately 6 km southeast from Carneiro 1 on the adjacent Braco Block. Mineralization is associated with sheeted quartz veins and quartz stockworks in subvertical E-W shear zones within a hydrothermally altered granitoid. The granitoid body was mapped over a strike length of 630 meters during the due diligence program.

Quartz veining and sheared altered host rock from the three principal showings were sampled using panel, chip-panel and grab sampling. On the Carneiro Block, samples were collected using 5 meter-long panels with 0.5m to 2m widths depending on vein thickness. Panels in the host rock material averaged 1m width. On the Braco Block (where exposure is more limited), panel samples were collected by systematically chip sampling available outcrop areas of variable dimensions, averaging 1m x 1m.

Samples were prepared and analyzed by BSI Inspectorate, a global commodity inspection and analysis company with offices in 110 countries. Sample preparation was conducted by BSI in Goiania, Brazil and analyses were performed at a BSI laboratory located in Sparks, Nevada. Samples were analyzed using two methods: standard 50g-FA and 50g-FA with gravimetric finish. Areas of high grade gold mineralization reported in previous work were sampled in triplicate to test for reproducibility.

Osisko and their joint-venture partner Amazonia Mineracao Ltda plan to conclude the Santa Catarina agreement in the coming month and will carry out an aggressive work program including drilling on the main mineralized areas confirmed by the due diligence program. The corridor between the Carneiro 1 and Italiano showings will also be the focus of detailed investigation.

Based on disappointing results from due diligence work on the Barro Alto property, located in Goias State, Osisko has decided not to proceed with additional work on that property.

Amazonia Mineracao Ltda is a privately held Brazilian based exploration and mining company, which has joint ownership of the high-grade Sertao gold mine, currently producing at a rate of 72,000 opy. Osisko Exploration Ltd. is a Canadian-based gold exploration company with a highly experienced international resource management team, focused on building shareholder value through the acquisition of low-cost, near-term development projects in Canada and Brazil. Robert Wares, P. Geo. and President of Osisko Exploration, is the Qualified Person responsible for the preparation of this news release.