Osisko Mining Corporation
TSX : OSK
FRANKFURT : EWX

Osisko Mining Corporation

March 01, 2005 17:27 ET

Osisko Commences Malartic Drill Program


NEWS RELEASE TRANSMITTED BY CCNMatthews

FOR: OSISKO EXPLORATION LTD.

TSX VENTURE SYMBOL: OSK

MARCH 1, 2005 - 17:27 ET

Osisko Commences Malartic Drill Program

MONTREAL, QUEBEC--(CCNMatthews - March 1, 2005) - Osisko Exploration
Ltd. (TSX VENTURE:OSK) (Deutsche Boerse:EWX) is pleased to announce that
a diamond drill program on its 100% owned Canadian Malartic property
will begin during the week of March 7, 2005. The Canadian Malartic
property has a reported historical resource of over 500,000 ounces gold
contained within five near-surface deposits (see November 23, 2004 press
release). The first phase of drilling will focus on the F zone,
containing a historical resource (pre 43-101) of 2,039,018 metric tonnes
@ 1.78 g/t Au (116,875 oz. gold).

Recently completed compilation of available data has revealed that the
historical resource estimate on the F zone was limited to the central
portion of the deposit, where drill data was most dense. The resource
calculation was based on data spread over a strike length of 210 meters,
a width of 40 to 120 meters and a maximum depth of 105 meters.
Interpretation of available geological information and previous drill
data indicates that this near-surface mineralized zone extends over a
strike length of 410 meters. Furthermore, the core of the deposit
appears to extend to a vertical depth of 120 to 150 meters.

Osisko management believes that the previous estimate was very
conservative and is confident that new drilling will ultimately lead to
a significant increase in the F zone gold resource. The upcoming
minimum 2000 meter drill program will test the core of the deposit along
most of its strike length, to a depth of 130 to 180 meters. The program
will include selected twin holes for verification of historical
intersections as well as infill holes along certain sections of the
deposit.

The Canadian Malartic property is located in the heart of the prolific
Abitibi region of Quebec and includes the former Canadian Malartic Mine,
which produced over 1 million ounces of gold at an average grade of 3.37
g/t Au between the years 1935 - 1965. Historical production in the
Malartic camp from 1935 to 1979 (Canadian Malartic and the adjacent
Barnat-Sladen and East Malartic Mines) totaled over 5 million ounces
(figures obtained from public data base of the Ministere des Ressources
Naturelles du Quebec). The Canadian Malartic property has excellent
infrastructure and is located on highway 117, near the town of Malartic
and 26 kilometers west of Val d'Or, Quebec. The East Malartic mill,
inactive since 2002, is located 2.5 km to the east of the property.

Mr. Robert Wares, P. Geo., is the Qualified Person responsible for the
preparation of this news release.

-30-

Contact Information