O3 Mining Inc. (TSX-V: OIII) (OTCQX: OIIIF) is pleased to announce that it has received results from its 1,368 metre drilling campaign on the Hygrade Fold area (North-West of Kierens pit), within the Marban Alliance project, in Val-d’Or, Québec, Canada.

Highlights:

• 33.3 g/t Au over 3.4 metres in hole O3MA-23-507 at a vertical depth of 138 metres, including 218.0 g/t over 0.5 metres on Zone 341
• Zone 341 now intersects high-grade intervals within four O3 Mining drill holes and remains open at depth
• 10.8 g/t Au over 2.2 metres in hole O3MA-23-494 at a vertical depth of 277 metres, including 31.6 g/t over 0.7 metres on Orion 10
• Orion 10 remains open for 300 metres along plunge

O3 Mining’s President and Chief Executive Officer, Mr. José Vizquerra commented: “These new high-grade intercepts from our 2023 winter drill program demonstrate the potential of finding high-grade shoots even at shallow depths within the Marban Alliance project. Located between the recently-released Malartic H resource area and the Marban Alliance pre-feasibility study resource area, the Hygrade Fold area delivers encouraging results”.

The 2023 winter drill campaign on the Hygrade Fold area covered three gold zones: 341, Orion 8, and Orion 10. The campaign on Zone 341 consisted of three follow-up drill holes from an intercept in hole O3MA-22-341 which returned 5.7 g/t Au over 7.6 metres (See news release of O3 Mining dated September 13, 2022 and entitled “O3 Mining Intersects 20.5 g/t Au over 2.2 Metres Including 73.5 g/t Au over 0.6 Metres at Hygrade Fold, Marban Engineering”). Holes were drilled approximately 40 metres apart and successfully expanded the high-grade mineralized zone up-dip and towards the east, with two out of three holes intersecting high-grade intervals (see Table 1).

On Orion, three holes were drilled to test the accuracy of the historical mining stope 3D model on Orion 8 and whether mineralization remains in the walls of the stopes. Hole O3MA-23-499 indicates that 4.2 metres of mineralized material at 2.2 g/t Au remains below the historical mining stope. One hole, O3MA-23-494, was extended beyond the Orion 8 deposit to reach the Orion 10 Zone at depth. This hole returned a high-grade intercept of 10.8 g/t Au over 2.2 metres showing the potential to expand the Orion 10 zone at depth (see Table 2).

Table 1: Near Surface Drill Hole Intercepts. Only intercepts above 5.0 g/t Au*metres are reported, cut-off 0.3 g/t Au and above 200 metres from surface.

Table 2: Deeper Drill Hole Intercepts. Only intercepts above 5.0 g/t Au*metres are reported, cut-off 1.0 g/t Au and below 200 metres from surface.

Figure 1: Marban Alliance Project Map

Figure 2: Location of significant intercepts at Hygrade Fold

About the Hygrade Fold Area

The Hygrade Fold area is located North-West of the Kierens pit, to the west of the area relating to the pre-feasibility study on the Marban Alliance project, and south of the Malartic H deposit. It contains several gold deposits and occurrences including Malartic Hygrade, Orion 8, Orion 10 and Zone 341. The mineralization is related to quartz and quartz-carbonate veining within mafic and ultramafic flows and locally spatially related to small intrusions.

Historical production was recorded from Malartic Hygrade and the Orion 8. Epoch, tonnages and grades of historical production are reported in Table 3.

Table 3: Historical production within the Hygrade Fold area

The 2023 winter drilling program at the Hygrade Fold area consisted of six drill holes totaling 1,368 metres. The parameters are listed in Table 4 for the entire program. All assay results have been received.

Table 4: Technical parameters of holes of the 2023 campaign at Hygrade Fold.

Qualified Persons

The scientific and technical content of this news release has been prepared, reviewed and approved by Mr. Sébastien Vigneau (OGQ #993), Principal Geologist of O3 Mining, who is a “qualified person” within the meaning of National Instrument 43-101 – Standards of Disclosure for Mineral Projects.

Quality Assurance/Quality Control

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.

About O3 Mining Inc.

O3 Mining Inc. 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 and expertise of a team of industry leaders as it grows towards becoming 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 (62,000 hectares) in Québec. O3 Mining trades on the TSX Venture Exchange and OTC Markets. The Corporation is focused on delivering superior returns to its shareholders and long-term benefits to its stakeholders.