Mr. John Burzynski reports

OSISKO MINING CORPORATE UPDATE

Osisko Mining Inc. has provided the following corporate update.

Wildfire situation in Eeyou Istchee James Bay

On July 17, Quebec's Ministry of Natural Resources and Forests lifted the access restriction to forests and roads on Crown land in the Eeyou Istchee James Bay area surrounding the Windfall site. To help and support provincial firefighting efforts, the Windfall camp is lodging over 100 firefighters from the Quebec firefighting agency, Societe de Protection des Forets Contre le Feu (SOPFEU), who are using the corporation's facilities as a base to fight regional fires. Windfall will resume underground drilling activities later this week and increase all other regular site activities back to normal levels as the local fire situation continues to improve in the coming weeks.

John Burzynski, chairman and chief executive officer, commented: "The Windfall team has done a fantastic job during the past six weeks -- a difficult and challenging period, working hand in hand and maintaining constant communications with local and provincial authorities to co-ordinate efforts. Their combined efforts helped maintain the Windfall site infrastructure intact. We were very fortunate that the forest fires passed within the immediate vicinity of the camp facilities several times, but did not cause any material damage to Windfall. Our thoughts and those of our joint venture partner Gold Fields remain with those local community members and neighbours who were displaced and those who lost their hunting and fishing cabins in the past month."

Sustainable development report

The corporation published its 2022 sustainable development report on July 18, 2023, which provides a detailed overview of the environmental, social and governance performance and economic contributions in the communities in which it operates. The report is available on the Osisko Mining website in English and French.

Sustainability is anchored in Osisko Mining's business strategy through the health and safety, human resources, environmental, community relations, human rights, and responsible procurement policies. In 2022, Osisko Mining achieved several milestones and made significant organizational progress. In addition, Osisko Mining has strengthened its support for renewable energies through its agreement with Miyuu Kaa for the transmission of hydroelectric power to the Windfall site. The 2022 sustainable development report covers Osisko Mining's activities on its Windfall, Quevillon and Urban Barry projects. It describes its ESG performance from Jan. 1 to Dec. 31, 2022, and provides comparative data from previous years.

Osisko Mining would like to thank employees, first nations, host communities, and financial and government partners, as well as shareholders, for their continued trust and support in its drive toward sustainable development.

Permitting process and the impact and benefit agreement

The Windfall environmental impact assessment review process by the COMEX is following its course, and the corporation is expecting that the Windfall mining group will receive the first round of follow-up questions in the coming months.

In parallel, the corporation expects to finalize the impact and benefit agreement with the Cree First Nation of Waswanipi and the Cree Nation government in 2023.

Receipt of mill shells

The Windfall mining group took delivery of its mill shells last month. All equipment is being stored at a warehouse located in Saint-Gabriel de Brandon, Que., until its final installation at the Windfall project.

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 Mining, who is a qualified person (within the meaning of National Instrument 43-101).

About the Windfall gold deposit

The Windfall gold deposit is located between Val d'Or and Chibougamau in the Abitibi region of Quebec, Canada. The mineral resource estimate on Windfall (with an effective date of June 7, 2022) and the mineral reserve estimate on Windfall (with an effective date of Sept. 1, 2022) are described in the technical report entitled "Feasibility Study for the Windfall Project, Eeyou Istchee James Bay, Quebec, Canada," and dated Jan. 10, 2023 (with an effective date of Nov. 28, 2022). The Windfall resource estimate, assuming a cut-off grade of 3.50 grams per tonne gold, comprises 811,000 tonnes at 11.4 g/t Au (297,000 ounces) in the measured mineral resource category, 10.25 million tonnes at 11.4 g/t Au (3,754,000 ounces) in the indicated mineral resource category and 12,287,000 tonnes at 8.4 g/t Au (3,337,000 ounces) in the inferred mineral resource category. The Windfall reserve estimate, assuming a 3.5 g/t operating, 2.5 g/t incremental and 1.7 g/t development cut-off grade, comprises 12,183,000 tonnes at 8.06 g/t Au (3,159,000 ounces) in the probable mineral reserves category. The key assumptions, limitations and methods used in the FS technical report, including the related Windfall resource estimate and Windfall reserve estimate, are described in the FS technical report, which was prepared in accordance with National Instrument 43-101 (Standards of Disclosure for Mineral Projects). The FS technical report is available on SEDAR under Osisko Mining's issuer profile. The Windfall gold deposit is currently one of the highest-grade resource-stage gold projects in Canada and has world-class scale. Mineralization occurs in three principal areas: Lynx, Main and Underdog. Mineralization is generally composed of subvertical lenses following intrusive porphyry contacts plunging to the northeast. The resources are defined from surface to a depth of 1,600 metres, including the Triple 8 (TP8) zone. The reserves are defined from surface to a depth of 1,100 metres. The deposit remains open along strike and at depth. Mineralization has been identified at surface in some areas and as deep as 2,625 metres in others with significant potential to extend mineralization down plunge and at depth.

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).

We seek Safe Harbor.