Highlights:

• 27 near surface economic intercepts reported today, including:
• 3.7 g/t Au over 11.0 metres in hole O3MA-22-334 from 166.0 metres, 140 metres to the north-west of one of the possible satellite pits identified in the Pre-feasibility study (“PFS”);
• 7.9 g/t Au over 3.2 metres in hole O3MA-22-423 from 39.1 metres, 400 metres to the east-south-east of one of the possible satellite pits identified in the PFS.

“These new results from our 2022 exploration program at Marban Alliance Engineering continue to highlight the potential to increase near-surface resources. In particular, the results published today suggest that with further work it may be possible to demontrate that the three satellite resource pits north of the Marban Alliance main pit could provide a basis to justify a single larger pit and show potential to expand eastward.“ O3 Mining’s President and Chief Executive Officer, Mr. Jose Vizquerra commented: ”

The Norlartic Extension trend has now been drilled over two kilometres at 80 metre spacings down to an average of 250 vertical metres. The dyke swarm hosting the gold mineralization at Norlartic Extension is geologically identical to the one hosting the Norlartic and Kierens mineralization. They correspond to mafic and intermediate fine-grained dykes, which have been successfully traced along the trend and serve as a marker to the mineralized corridor. The PFS resource estimate generated three small pits using historical drill results along the Norlartic Extension trend immediately north of the Marban Alliance pit. The new drill results obtained in that area returned additional significant intercepts, which suggest the possibility that an updated resource estimate could confirm and expand this inferred resource.

The Marban Alliance Dyke mineralization is associated with quartz vein stockwork hosted in felsic dykes. They correspond to a series of zones located in the north-eastern portion of the Marban Alliance pit. The three intercepts reported are located along the north-western extension of those zones or along a stacked zone located further north.

Figure 1 – Marban Alliance Project Surface Map

Figure 2 – Norlartic Extension Significant Intercepts

Table 1: Near Surface Expension Drill Hole Intercepts (only intercepts above 5.0 g/t Au*m are reported, cut-off 0.3 g/t Au and above 300m from surface)

True width determination is currently unknown but is estimated at 65-80% of the reported core length interval for the zones. Assays are uncut except where indicated.

The drilling campaign on Norlartic Extension comprises 56 drill holes totaling 13,692 metres. The parameters are listed in Table 2 for the entire program. Significant intercepts have been published in the last months (Press Release – July 6, 2022, and December 22, 2022) Those drill holes also contain a significant amount of intercepts with grade-thickness values below 5 m*g/t Au.

Table 2: Technical parameters of holes of the 2022 campaign on Norlartic Extension and Marban Alliance Dyke

For full drilling results, please see our website www.o3mining.com.

The scientific and technical content of this news release has been reviewed, prepared and approved by Mr. Sébastien Vigneau (OGQ #993), Principal Geologist, who is a “qualified person” as defined by National Instrument 43-101 – Standards of Disclosure for Mineral Projects (“NI 43-101”).

For further information on the Marban Alliance project, please see the technical report, entitled “NI 43-101 Pre-feasibility Study of the Marban Alliance Engineering Project” and dated October 7, 2022 (with an effective date of September 6, 2022), (the “Marban Alliance PFS”).  Reference should be made to the full text of the Marban Alliance PFS for the assumptions, qualifications and limitations relating to the PFS. The Marban Alliance PFS is available on SEDAR (www.sedar.com) under O3 Mining’s issuer profile.

Mineral resources that are not mineral reserves do not have demonstrated economic viability.

Intercepts occur within geological confines of major zones but have not been correlated to individual vein domains at this time. Half-core samples are shipped to Agat laboratory in Val-d’Or, Québec, and Mississauga, Ontario for assaying. The core is crushed to 75% passing -2 mm (10 mesh), a 250 g split of this material is pulverized to 85% passing 75 microns (200 mesh) and 50 g is analyzed by Fire Assay (FA) with an Atomic Absorption Spectrometry (AAS) finish. Samples assaying >10.0 g/t Au are re-analyzed with a gravimetric finish using a 50 g charge.

Commercial certified standard material and blanks are systematically inserted by O3 Mining’s geologists into the sample chain after every 18 core samples as part of the quality assurance and quality control (“QA/QC”) program. Third-party assays are submitted to other designated laboratories for 5% of mineralized samples. Drill program design, QA/QC, and interpretation of results are performed by qualified persons employing a QA/QC program consistent with NI 43-101 and industry best practices.

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

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. Forward-looking statements including, but are not limited to, statements with respect to planned and ongoing drilling, the significance of drill results, the ability to continue drilling, the impact of drilling on the definition of any resource, the ability to incorporate new drilling in an updated technical report and resource model. 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. Except for statements of historical fact relating to the Corporation, certain information contained herein constitutes forward-looking statements Forward-looking information is based on estimates of management of the Corporation, at the time it was made, involves known and unknown risks, uncertainties and other factors which may cause the actual results, performance or achievements of the companies 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 drill results at Malartic H; the significance of drill results; the ability of drill results to accurately predict mineralization; the ability of the Corporation to produce an updated mineral resource estimate on Malartic in Q2 2023 (or at all); the ability of any material to be mined in a matter that is economic. 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, the parties cannot assure shareholders and prospective purchasers of securities 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 the Corporation nor any other person assumes responsibility for the accuracy and completeness of any such forward-looking information. The Corporation believes that this forward-looking information is based on reasonable assumptions, but no assurance can be given that these expectations will prove to be correct and such forward-looking statements included in this press release should not be unduly relied upon. The Corporation 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. These statements speak only as of the date of this news release.

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SOURCE O3 Mining Inc.