Osisko Mining Inc. provided an update from the ongoing drill program at its 50% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Quebec. The 2023 drilling campaign primarily targeted infill areas. Since the start of the year, over 95,000 metres have been drilled by 8 underground rigs focused on the Lynx segment of the deposit.

Highlights from the 2023 drill program are presented below and include 320 intercepts from 248 drill holes and 1 wedge. These highlights are intercepts with a metal factor (grams*meters) greater than 20. The intercepts are all located within the defined mineral resource estimate ("MRE") blocks as described in Osisko's feasibility study on Windfall.

and have targeted upgrading inferred mineral resources to measured or indicated mineral resources or indicated minerals resources to measured mineral resources as applicable. The 1-kilogram screen assay method is selected by the geologist when samples contain coarse gold or present a higher percentage of pyrite than surrounding intervals. Selected samples are also analyzed for multi-elements, including silver, using a Four Acid Digestion-ICP-MS method at ALS Laboratories.

Drill program design, Quality Assurance/Quality Control ("QA/QC") and interpretation of results is performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices. Standards and blanks are included with every 20 samples for QA/QC purposes by the Corporation as well as the lab. 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) (the "Windfall Resource Estimate") and the mineral re serve estimate on Windfall. The Windfall Reserve Estimate, assuming a cut-off grade of 3.50 g/t Au, comprises 811,000 tonnes at 11.4 g/t Au (297,000 ounces) in the measured mineral resource category, 10,250,000 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.