News Press Releases

O3 Mining Files Technical Report for Marban Engineering Mineral Resource Estimate Update

V.OIII | April 14, 2022

TSXV:OIII | OTCQX:OIIIF - O3 Mining

TORONTO, April 14, 2022 /PRNewswire/ - O3 Mining Inc. (TSXV: OIII) (OTCQX: OIIIF) ("O3 Mining" or the "Corporation") is pleased to announce that it has filed a technical report in accordance with National Instrument 43-101 – Standards of Disclosure for Mineral Projects to update the mineral resource estimate on its 100% owned Marban Project. The technical report entitled "NI 43-101 Technical Report and Mineral Resource Estimate for Marban Engineering, Val-d'Or, Quebec" with an effective date of February 27, 2022, has been prepared for O3 Mining by Ausenco Engineering Canada Inc. and G Mining Services. The technical report is available on SEDAR (www.sedar.com) under O3 Mining's issuer profile.

O3 Mining's news release dated March 1, 2022 (entitled "O3 Mining Increases M&I Open-Pit Resource by 29% for Marban Engineering") summarizes key results, assumptions and estimates contained in the report. The Corporation is pleased to report there are no material differences between the key results, assumptions and estimates contained in the news release dated March 1, 2022, and the content of the technical report filed today.

About O3 Mining Inc.

O3 Mining Inc., an Osisko Group company, is a gold explorer and mine developer on the road to produce from its highly prospective gold camps in Québec, Canada. O3 Mining benefits from the support, previous mine-building success, and expertise of the Osisko team as it grows towards being a gold producer with several multi-million-ounce deposits in Québec.

O3 Mining is well-capitalized and owns a 100% interest in all its properties (66,000 hectares) in Québec. O3 Mining trades on the TSX Venture Exchange (TSXV: OIII) and OTC Markets (OTCQX: OIIIF). The Corporation is focused on delivering superior returns to its shareholders and long-term benefits to its stakeholders. Further information can be found on our website at https://o3mining.com

Cautionary Note Regarding Mineral Resource Estimate

Readers are cautioned that mineral resources are not mineral reserves and that the economic viability of mineral resources that are not mineral reserves has not been demonstrated. The mineral resource estimate described in this news release may be materially affected by geology, environmental, permitting, legal, title, socio-political, marketing, or other relevant issues. The mineral resource estimate is classified in accordance with the Canadian Institute of Mining, Metallurgy and Petroleum's "CIM Definition Standards on Mineral Resources and Mineral Reserves" incorporated by reference into National Instrument 43-101 – Standards of Disclosure for Mineral Projects. Readers are cautioned not to assume that further work on the stated mineral resources will lead to mineral reserves that can be mined economically.

Neither the TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of this news release. No stock exchange, securities commission or other regulatory authority has approved or disapproved the information contained herein.