Mr. John Burzynski reports

OSISKO MINING SIGNS BINDING LETTER AGREEMENT WITH BONTERRA RESOURCES FOR EXPLORATION EARN-IN AND JOINT VENTURE ON URBAN-BARRY PROPERTIES

Osisko Mining Inc. has entered into a binding letter of agreement with Bonterra Resources Inc. for a 70-per-cent exploration earn-in and joint venture on all of the Urban-Barry properties held by Bonterra (hosting the Gladiator and Barry deposits), in addition to the adjoining Duke and Lac Barry properties, all located in Quebec's Eeyou Istchee James Bay region. The Duke property is currently 70 per cent owned by Bonterra and 30 per cent owned by Osisko, and the Lac Barry property is currently 85 per cent owned by Bonterra and 15 per cent owned by Gold Royalties Corp. The properties total 496 claims over 22,508 hectares.

Under the binding letter of agreement, Osisko has agreed to pay Bonterra an initial upfront payment of $1-million in cash (payable within one business day of the signing of the binding letter of agreement) and an additional $4-million in cash upon the parties entering into the definitive agreement. Under the exploration earn-in, Osisko has agreed to finance $30-million in work expenditures over a three-year period to earn a 70-per-cent undivided interest in the properties, in accordance with annual work expenditures $10-million in each year (which can be prepaid at Osisko's option).

After completion of the exploration earn-in, Osisko and Bonterra have agreed to form a joint venture entity or contractual joint venture in such form as the parties may agree, each acting reasonably, taking into consideration any tax and other factors relevant to the parties.

During the exploration earn-in, and upon and following the formation of the joint venture, Osisko will be the operator of the properties. Upon completion of the exploration earn-in and the formation of the joint venture, Osisko and Bonterra will form a management committee to provide direction to the operator on exploration programs for the Urban-Barry properties.

Osisko and Bonterra have agreed to negotiate in good faith, settle and enter into definitive documentation providing for the exploration earn-in as soon as practicable following the date hereof, subject to the satisfaction of certain customary conditions precedent.

Osisko may withdraw from the exploration earn-in at any time upon written notice to Bonterra. In the event of an election to withdraw from the exploration earn-in, Osisko will forfeit all rights and interests in the properties with no further liability, and the definitive documentation shall be immediately terminated upon such election.

About the Urban-Barry properties

Barry deposit

The Barry deposit is a shear-hosted gold deposit with multiple parallel, subvertical shear zones and a second set of veins dipping 25 degrees to 60 degrees to the southeast. The gold mineralization consists of disseminated sulphides within the shear zones and the veins with local visible gold. The Barry deposit has been delineated over 1.4 kilometres along strike and 700 metres vertical, and the deposit remains open for expansion.

SLR Consulting (Canada) completed a mineral resource estimate for Bonterra on the Barry deposit for both open-pit and underground scenarios. The combined open-pit and underground mineral resource estimate for the Barry deposit is: (i) measured mineral resources of 2,076,000 tonnes at 3.04 grams per tonne (g/t) gold (Au) for 203,000 ounces (oz) Au; (ii) indicated mineral resources of 3,023,000 tonnes at 5.01 g/t Au for 487,000 oz Au; and (iii) inferred mineral resources of 4,379,000 tonnes at 4.89 g/t Au for 689,000 oz Au. The Barry mineral resource estimate is supported by the technical report (as defined herein).

Gladiator deposit

Gold mineralization at the Gladiator deposit is hosted within sheared veins of quartz-carbonate composition, with sericite, chlorite, tourmaline with pyrite, chalcopyrite, sphalerite, galena and visible gold. The veins are divided into four groupings. The Gladiator deposit has been outlined by diamond drilling to a strike length of 1,600 metres and depth of 1,100 metres.

SLR Consulting (Canada) completed a mineral resource estimate for Bonterra on the Gladiator deposit. The mineral resource estimate for the Gladiator deposit is: (i) indicated mineral resources of 1,413,000 tonnes at 8.61 g/t Au for 391,000 oz Au; and (ii) inferred mineral resources of 4,174,000 t at 7.37 g/t Au for 989,000 oz Au. The Gladiator mineral resource estimate is supported by the technical report.

Duke property

The Duke property consists of 81 strategic mineral claims totalling 3,590 hectares adjacent to the Gladiator deposit. The Duke property mineralization is associated with multiple subparallel, moderately dipping to subvertical, shear-hosted quartz-carbonate-chlorite veins and stockworks with minor pyrite, and gold trending northeast to east-west, hosted within intermediate to mafic volcanics and tuffs with local felsic intrusions. Bonterra and Osisko have a 70-per-cent and 30-per-cent interest, respectively, in the Duke property.

Technical report

The mineral resource estimates for the Barry and Gladiator deposits are supported by the technical report entitled "Technical report on the Gladiator and Moroy deposits and the Bachelor mine, and preliminary economic assessment on the Barry deposit, Northwestern Quebec, Canada, report for NI 43-101," dated July 25, 2022 (with an effective date of June 1, 2022), prepared for Bonterra by SLR Consulting (Canada). Reference should be made to the full text of the technical report for the assumptions, qualifications and limitations set forth therein, a copy of which is available on SEDAR+ under Bonterra's issuer profile.

Qualified person

The scientific and technical content in this news release has been reviewed and approved by Mathieu Savard, PGeo (OGQ No. 510), president of Osisko, who is a qualified person as defined by National Instrument 43-101 -- Standards of Disclosure for Mineral Projects.

About Osisko Mining Inc.

Osisko Mining is a mineral exploration company focused on the acquisition, exploration and development of precious metal resource properties in Canada. Osisko Mining holds a 50-per-cent interest in the high-grade Windfall gold deposit located between Val d'Or and Chibougamau in Quebec, and holds a 50-per-cent interest in a large area of claims in the surrounding Urban-Barry area and nearby Quevillon area (over 2,300 square kilometres).

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