OSISKO MINING INC. FILES EARLY WARNING REPORT

IN RESPECT OF O3 MINING INC.

Toronto, Ontario (July 14, 2021) – Osisko Mining Inc. (TSX:OSK) (the “Corporation“) announces that it has filed an early warning report in respect of its holdings in O3 Mining Inc. (“O3 Mining“). After giving effect to four trades ending on July 13, 2021, which settled through the facilities of the TSX Venture Exchange, the Corporation acquired an aggregate of 83,400 common shares of O3 Mining (“O3 Shares“), representing approximately 0.12% of the issued and outstanding O3 Shares, for aggregate gross proceeds of $185,309.72 (collectively, the “Acquisitions“).

At the time of the prior early warning report filed by the Corporation in respect of O3 Mining on August 17, 2020 (the “Prior Report“), the Corporation had beneficial ownership of, or control and direction over, 18,277,898 O3 Shares, representing approximately 30.3% of the issued and outstanding O3 Shares on a basic basis (based on there being 60,296,508 O3 Shares issued and outstanding as of the date of the Prior Report).

Since the date of the Prior Report and prior to giving effect to the Acquisitions, O3 Mining issued an aggregate of 7,743,758 O3 Shares, which through no action on the part of the Corporation, resulted in the Corporation’s ownership in O3 Shares being diluted to approximately 26.9% of the issued and outstanding O3 Shares on a basic basis (based on there being 68,040,266 O3 Shares issued and outstanding as of the date hereof and Osisko holding 18,277,898 O3 Shares (as disclosed in the Prior Report)).

Immediately after giving effect to the Acquisitions, Osisko had beneficial ownership of, or control and direction over, 18,361,298 O3 Shares, representing approximately 27.0% of the issued and outstanding O3 Shares on a basic basis (based on there being 68,040,266 O3 Shares issued and outstanding as of the date hereof).

The Corporation acquired the O3 Shares for investment purposes. The Corporation intends to review, on a continuous basis, various factors related to its investment in O3 Mining, and may decide to acquire or dispose of additional securities of O3 Mining as future circumstances may dictate.

This news release is being issued in accordance with National Instrument 62-103 – The Early Warning System and Related Take-Over Bid and Insider Reporting Issues in connection with the filing of an early warning report dated July 14, 2021. The early warning report respecting the Acquisitions has been filed on SEDAR (www.sedar.com) under O3 Mining’s issuer profile. To obtain a copy of the early warning report filed by the Corporation, please contact John Burzynski at (416) 363-8653 or refer to SEDAR (www.sedar.com) under O3 Mining’s issuer profile.

For further information on the Corporation please contact:

John Burzynski
President & Chief Executive Officer
Telephone: (416) 363-8653

The Corporation’s head office is located at 155 University Avenue, Suite 1440, Toronto, Ontario M5H 3B7.