Osisko Resumes Operations at Windfall

TORONTO, May 15, 2020 - Osisko Mining Inc. (OSK:TSX. "Osisko" or the "Corporation") announced today that in accordance with permission from the Government of Quebec to resume exploration activities, and in close collaboration with the Cree First Nation of Waswanipi and the Cree Nation Government, a path has been identified for the resumption of operations at its 100% owned Windfall gold project located in the Abitibi greenstone belt, Urban Township, Eeyou Istchee James Bay, Qu?bec. The collaboration builds on a long standing positive relationship which has allowed the Cree Nation and Osisko to address difficult subjects during these challenging times and provides for mutual support in ensuring the safety of community members and the work force of Osisko Mining Inc.

The initial group of employees and contractors have returned to the Windfall site, and drilling operations with six rigs will recommence this weekend. Additional drills and workers will progressively return to work over the course of the coming weeks, with operations expected to return to full capacity by late June. The health and safety of Osisko's workforce, their families and the communities in which we operate remains the number one priority for Osisko. Osisko is committed to fully supporting safety measures recommended by the Quebec Public Health Expertise and Reference Centre and by the CNESST for our workforce, families and communities. Osisko thanks our workforce, partners and all stakeholders for their understanding and support, and looks forward to a safe and measured approach to the return to work.

About Osisko Mining Inc.
Osisko is a mineral exploration company focused on the acquisition, exploration, and development of precious metal resource properties in Canada. Osisko holds a 100% interest in the high-grade Windfall Lake gold deposit located between Val-d'Or and Chibougamau in Qu?bec and holds a 100% undivided interest in a large area of claims in the surrounding the Urban Barry area and nearby Qu?villon area (over 2,700 square kilometres).

Cautionary Note Regarding Forward-Looking Information
This news release contains "forward-looking information" within the meaning of the applicable Canadian securities legislation that is based on expectations, estimates, projections and interpretations as at the date of this news release. The information in this news release about the Windfall Lake gold deposit being one of the highest grade resource-stage gold projects in Canada; the term of any Government order, or of the suspension of operations described therein; mineralization; the potential to extend mineralization up and down-plunge and at depth at the Windfall Lake gold deposit; the ability to realize upon any mineralization in a manner that is economic; the ability to complete any proposed exploration activities and the results of such activities, including the continuity or extension of any mineralization; and any other information herein that is not a historical fact may be "forward-looking information". Any statement that involves discussions with respect to predictions, expectations, interpretations, beliefs, plans, projections, objectives, assumptions, future events or performance (often but not always using phrases such as "expects", or "does not expect", "is expected", "interpreted", "management's view", "anticipates" or "does not anticipate", "plans", "budget", "scheduled", "forecasts", "estimates", "believes" or "intends" or variations of such words and phrases or stating that certain actions, events or results "may" or "could", "would", "might" or "will" be taken to occur or be achieved) are not statements of historical fact and may be forward-looking information and are intended to identify forward- looking information. This forward-looking information is based on reasonable assumptions and estimates of management of the Corporation at the time such assumptions and estimates were made, and involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of Osisko to be materially different from any future results, performance or achievements expressed or implied by such forward-looking information. Such factors include, among others, risks relating to the terms and duration of any government orders suspending or limiting operations that are applicable to Osisko; the responses of relevant governments to the COVID-19 outbreak and the effectiveness of such responses; the ability of exploration activities (including drill results) to accurately predict mineralization; errors in management's geological modelling; the ability of Osisko to complete further exploration activities, including drilling; property interests in the Windfall Lake gold project; the ability of the Corporation to obtain required approvals and complete transactions on terms announced; the results of exploration activities; risks relating to mining activities; the global economic climate; metal prices; dilution; environmental risks; and community and non-governmental actions. Although the forward-looking information contained in this news release is based upon what management believes, or believed at the time, to be reasonable assumptions. Osisko cannot assure shareholders and prospective purchasers of securities of the Corporation that actual results will be consistent with such forward-looking information, as there may be other factors that cause results not to be as anticipated, estimated or intended, and neither Osisko nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information, Osisko does not undertake, and assumes no obligation, to update or revise any such forward-looking statements or forward-looking information contained herein to reflect new events or circumstances, except as may be required by law.

For further information please contact:
John Burzynski
President and Chief Executive Officer
Telephone: (416) 363-8653