Onyx Gold Corp. (TSX-V: ONYX) (OTCQX: ONXGF)  is pleased to report assay results from 31 additional drill holes at the Argus Gold System and along the Pipestone Fault corridor at its 100%-owned Munro-Croesus Project, located 75 kilometers east of Timmins, Ontario. (Figure 4).

Drilling has now encountered gold at multiple locations across an approximately 2.6-kilometer trend at Argus. In addition to more strong results from Argus Main, first-pass drilling at Big Break, 700 meters southeast of Argus Main, and JM, a further 500 meters southeast, have identified new gold-bearing areas beyond the approximately 1.4-kilometer Argus Gold System footprint previously outlined. These are separate mineralized targets, with extensive ground between them still requiring follow-up.

Highlights

• Argus Main – Drill hole MC26-343 intersected 0.7 g/t gold over 166.0 meters, including 1.6 g/t Au over 21.7 m and 2.2 g/t Au over 9.9 m, reinforcing the scale of mineralization and potential for higher-grade zones.

• Big Break – First-pass drilling approximately 700 m southeast of Argus Main returned
  0.6 g/t Au over 22.0 m in MC26-291 and 0.9 g/t Au over 11.0 m in MC26-295, testing a structurally disrupted magnetic-low anomaly within the same favourable volcanic sequence hosting Argus.

• JM – MC26-350 returned 18.8 g/t Au over 2.3 m, including 25.1 g/t Au over 1.2 m; MC26-330A returned 1.4 g/t Au over 10.4 m. Both holes were drilled in the JM area, approximately 1.2 km southeast of Argus Main.

• Gold mineralization has now been identified at multiple locations along an approximately 2.6 km trend associated with the Pipestone Fault, supporting further exploration for additional zones. Onyx controls approximately 8 km of prospective strike, of which approximately 4 km has been drill tested. This leaves significant portions of the corridor available for target generation and first-pass testing.

• Significant drill results remain to be reported – Approximately 91% of the 110,000 m program is complete, but results have been released for only 146 of 264 completed holes (55%). Four rigs remain active, with approximately 10,000 m of drilling remaining.

“These results are expanding our view of the broader discovery potential at Munro-Croesus, well beyond the original Argus discovery area,” said Brock Colterjohn, President and CEO of Onyx Gold. “At Argus Main, we continue to intersect broad zones of gold mineralization containing multiple higher-grade intervals. What is particularly encouraging is that first-pass drilling at Big Break and JM has now identified gold up to 1.2 kilometers southeast of Argus Main, within the same favourable volcanic sequence. While these new areas are still at an early stage, the results suggest that the geological conditions associated with gold mineralization at Argus may be repeated elsewhere along the Pipestone corridor. With approximately eight kilometers of prospective strike under Onyx control, we have a significant opportunity to apply our evolving geological model to a much larger area. Our focus remains on expanding the established Argus zones while systematically exploring for additional gold-bearing centres along the trend.”

Discussion of Argus Gold System and Pipestone Drill Results

Argus Main Drill Results

Three drill holes reported today are part of the ongoing test of the plunging higher-grade zone on the eastern margin of Argus Main and following up on recent strong drilling results including 1.7 g/t Au over 67.0 m, including 13.2 g/t Au over 6.0 m, in drill hole MC26-340 (see Company news release dated August 19). The drilling is part of the Company’s overall strategy to define and expand the known zones at Argus Main and Argus North (See Figures 1/2/3). Highlights include:

• MC26-343: 0.7 g/t Au over 166.0 m, including
  • 1.6 g/t Au over 21.7 m, including
    • 5.8 g/t Au over 3.0 m, and including

• 1.3 g/t Au over 20.7 m, including
  • 5.4 g/t Au over 2.9 m, and including

• 2.2 g/t Au over 9.9 m, including
  • 5.6 g/t Au over 2.9 m, including
    • 12.9 g/t Au over 0.7 m

• MC26-311EXT: 0.7 g/t Au over 20.7 m, including
  • 1.2 g/t Au over 10.0 m, including
    • 2.0 g/t Au over 4.0 m

Argus Main has been tested from near surface to approximately 400 m vertical depth and remains open along strike and at depth. The mineralized zone displays characteristics also observed at Argus North, including variolitic to pillowed mafic volcanic host rocks, albite-carbonate-silica alteration, fracturing and localized crackle brecciation accompanied by fine-grained pyrite. The multiple higher-grade intervals in MC26-343 reinforce the importance of defining structural controls and potential plunging zones within the broader mineralized envelope.

Big Break Drill Results

Big Break is located approximately 700 m southeast of Argus Main, where magnetic data indicate a possible northeast-trending break within the favourable mafic volcanic package. (Figures 1 and 2). The setting was selected because the coincidence of favourable host rocks, structural complexity and a magnetic-low response resembles geological features being investigated at Argus North. The inferred fault geometry remains to be confirmed by additional geological work.

Twelve holes are reported from first-pass drilling at Big Break. Several returned gold-bearing intervals that warrant follow-up testing, including:

• MC26-291: 0.6 g/t Au over 22.0 m, including
  • 1.4 g/t Au over 5.0 m

• MC26-295: 0.9 g/t Au over 11.0 m, including
  • 4.6 g/t Au over 2.0 m

JM and JM Variolitics Drill Results

JM is approximately 500 m southeast of Big Break near the upper contact of the same favourable volcanic sequence. The historic JM showing occurs in variolitic volcanic rocks with silicification, sericite and iron-carbonate alteration, accompanied by pyrite and arsenopyrite. Historical surface sampling returned up to 15.0 g/t Au in waste rock and 11.0 g/t Au from a pit wall.

The current program tested a different location south of the historic showing where new geological and magnetic information suggest an interpreted northeast-trending structure. The objective was to assess whether the combination of favourable host stratigraphy and structurally prepared rocks associated with Argus could occur farther southeast along the Pipestone corridor.

Twelve drill holes are reported today with highlights including:

• MC26-350: 18.8 g/t Au over 2.3 m, associated with a lamprophyre dike cutting mafic variolitic basalt, including
  • 25.2 g/t Au over 1.2 m

• MC26-330A: 1.4 g/t Au over 10.4 m, including
  • 2.0 g/t Au over 5.4 m, including
    • 6.0 g/t Au over 0.7 m

Complete significant assay results are provided in Table 1 and shown in Figures 1/2/3.

Updated collar coordinates for all drill holes reported to date can be found on the Company’s website here.

The Argus-Pipestone Trend – A Larger Gold Discovery Opportunity

The Argus Gold System is an emerging, large-scale gold system comprising multiple zones of mineralization immediately north of the regional Pipestone Fault. The currently recognized zones include Argus Main, Argus North and Argus West, with additional exploration targets including Big Break and JM currently being drill tested across the broader structural Pipestone and Argus Fault corridors. Drilling to date has demonstrated gold mineralization across approximately 2.6 km of strike and more than 700 m vertically.

At Argus North and Argus Main, drilling has defined broad zones of disseminated gold mineralization containing steeply plunging, higher-grade zones associated with northeast-trending structures and favourable volcanic stratigraphy. These higher-grade zones appear to have a periodicity along the broader mineralized trend, providing a geological framework for targeting additional zones across the Argus Gold System.

Onyx controls approximately 8 km of prospective strike along the Pipestone Fault corridor. Only 4 km (50%) of the Pipestone Fault has been drilled by the Company to date. This leaves significant portions of the corridor available for target generation and first-pass testing.

Elsewhere at Munro-Croesus, the separate interpreted Argus Fault corridor extends for approximately 16 km, including the sediment-hosted Flipper area approximately 3 km south of Argus (see Company news release dated October 5, 2026). The two corridors create distinct opportunities to explore for additional gold-bearing centres across the Property.

The strategy is to advance the established Argus mineralized zones while systematically evaluating Big Break, JM and other prospective structural intersections along the Pipestone and Argus Fault corridors. Mapping, magnetic interpretation, targeted step-outs and drill fences will be used to refine the orientation of mineralization, establish whether better-grade zones repeat, and rank the next tests along the corridor. The pace and priority of future drilling will be guided by additional geological and assay results.

Update on 2026 Exploration Program

The Company continues to execute its fully funded 110,000 m exploration program at Munro-Croesus, with 264 drill holes totalling approximately 100,000 m (91%) completed to date.

Assays have been released for 146 drill holes, representing approximately 55% of holes completed, with approximately 10,000 m remaining to be drilled. Four diamond drill rigs are currently operating at the Project.

Drilling will continue on two fronts: (1) expanding the established Argus Main and North zones, including higher-grade plunging targets; and (2) defining the orientation, extent and potential repetitions of gold mineralization at Big Break, JM and additional structural targets along the Pipestone corridor. Geological mapping, high-resolution magnetics and targeted drill fences will guide priorities, with step-out programs adjusted as new results are received.

The Company anticipates completing the 110,000 m program by year-end and is fully funded with approximately $9 million in cash.

Figure 1 – Plan Map of Argus Zone Drill Results

 Figure 2 – High-resolution UAV Magnetics Highlighting the Pipestone Fault Corridor with Recent Argus Drill Results

 Figure 3 – Cross Section of Argus Main Drill Results

Figure 4 – Location of the Munro-Croesus Gold Project, Ontario

Table 1 – Significant Assay Results Reported in this Release

Table 1 – Significant Assay Results Reported in this Release (Continued)

Table 1 – Significant Assay Results Reported in this Release (Continued)

The Munro-Croesus Project

The Munro-Croesus Project is located along Highway 101 in the heart of the Abitibi greenstone belt, Canada’s premier gold mining jurisdiction (Figure 3). This large, 100%-owned land package includes the past-producing Croesus Gold Mine, which yielded some of the highest-grade gold ever mined in Ontario. Extensive land consolidation since 2020 has unified the patchwork of patented and unpatented mining claims surrounding the Croesus Gold Mine into one coherent package and enhanced the project’s exploration potential.

The Project covers 114 km² of highly prospective geology within the influence of major gold-bearing structural breaks. Bulk-tonnage gold deposits located in the immediate region include the Fenn-Gib gold project being developed by Mayfair Gold Corp., and the Tower Gold Project being developed by STLLR Gold Inc.

Qualified Person

Ian Cunningham-Dunlop, P.Eng., Executive Vice President of Onyx Gold Corp. and a Qualified Person as defined by National Instrument 43-101, has reviewed and approved the scientific and technical information contained in this news release.

About Onyx Gold

Onyx Gold Corp. is a Canadian exploration company focused on unlocking district-scale gold opportunities in two of the country’s most prolific and proven mining jurisdictions – Timmins, Ontario, and Yukon Territory.

In the Timmins Gold Camp, Onyx controls an extensive portfolio anchored by the Munro-Croesus Property, host to the historic high-grade Croesus Mine and site of the Company’s recent Argus North discovery. Complementing Munro-Croesus are two large, early-stage projects – Golden Mile, a 140 km² property situated just 9 km from Discovery Silver’s multi-million-ounce Hoyle Pond Mine, and Timmins South, a 187 km² land package strategically positioned around the Shaw Dome structure, offering exceptional discovery potential.

Beyond Ontario, Onyx holds a commanding land position across four properties in Yukon’s Selwyn Basin, an area rapidly gaining recognition for new gold discoveries and growing exploration investment. The Company’s King Tut Property sits approximately 50 km south of Snowline Gold’s Valley deposit and adjacent to Fireweed Metals’ MacPass property.

Led by an experienced team with a strong track record of discovery, development, and value creation, Onyx Gold is well-funded and committed to delivering shareholder value through disciplined exploration, strategic growth, and responsible resource development.