Argus Main Returns 1.0 g/t Gold over 93.0 Meters; New Drilling 250 Meters Northeast Intersects 2.6 g/t Gold over 7.3 Meters

Onyx Gold Corp. (TSX-V: ONYX) (OTCQX: ONXGF)  is pleased to report results from 17 drill holes at its 100%-owned Munro-Croesus Project, located 75 km east of Timmins, Ontario. The results extend gold mineralization at both Argus North and Argus Main and identify a new area of mineralization 250 m northeast of Argus Main along the projected Argus Fault corridor.

The most significant result is from Argus North, where hole MC26-274A returned 3.5 g/t gold over 28.1 meters, including 5.3 g/t Au over 17.8 m. Drilling has now intersected Argus North from near surface to more than 700 m vertical depth, and the zone remains open at depth and along strike.

At Argus Main, three (3) deeper holes continued to intersect broad gold mineralization, including 1.0 g/t Au over 93.0 m in hole MC26-324. Approximately 250 m to the northeast, first-pass drilling intersected 2.6 g/t Au over 7.3 m in a previously undrilled area, providing a new target for follow-up.

Highlights from Argus North

• Argus North continues at depth: the zone has now been intersected to more than 700 m vertically and remains open.
• MC26-274A: 3.5 g/t Au over 28.1 m, including 5.3 g/t Au over 17.8 m, including 23.1 g/t Au over 1.0 m and 11.4 g/t Au over 2.0 m
• MC26-271: 3.5 g/t Au over 19.0 m, including 8.3 g/t Au over 6.6 m, including 24.3 g/t Au over 1.0 m

Highlights from Argus Main

• Argus Main is developing as a broad mineralized system: all three holes reported from the current step-out program returned multiple gold intervals, including higher-grade sections within wider envelopes.
• MC26-324: 1.0 g/t Au over 93.0 m, including 2.0 g/t Au over 20.0 m, including 9.8 g/t Au over 1.0 m; plus a separate interval of 0.9 g/t Au over 33.0 m, including 3.0 g/t Au over 6.0 m. Importantly, the hole finished in strong mineralization, returning up to 19.3 g/t Au over 0.7 m in the final four meters and ending in 1.4 g/t Au over the last meter, indicating the system could continue at depth. Follow-up drilling is planned to extend the hole and test for further mineralization.
• MC26-317: 0.8 g/t Au over 98.9 m, including 1.1 g/t Au over 35.8 m and 2.7 g/t Au over 5.9 m

Highlights from New Northeast Target

• The Argus trend is expanding: first-pass drilling 250 m northeast of Argus Main within massive and pillowed mafic flows has intersected gold along the projected Argus Fault corridor, opening a new area for systematic follow-up.
• MC26-316: 2.6 g/t Au over 7.3 m; including 8.8 g/t Au over 1.5 m
• MC26-314: 1.3 g/t Au over 5.7 m; including 2.2 g/t Au over 3.0 m

“Every phase of drilling continues to strengthen our understanding of the Argus Gold System,” said Brock Colterjohn, President & CEO. “Today’s results demonstrate that both Argus North and Argus Main continue to grow with depth while maintaining the broad, continuous style of mineralization that has become characteristic of the system. Just as importantly, our first drill holes completed 250 m northeast of Argus Main intersected gold mineralization, highlighting the broader prospectivity of the Argus Fault corridor beyond the areas we have drilled to date.”

“With four drill rigs operating and more than 110,000 m of drilling planned for this drill program, we remain focused on systematically expanding the known zones while testing additional targets across the corridor. We believe we are still in the early stages of defining the full scale of the Argus Gold System.”

Discussion of Argus North Drill Results

Nine holes tested the west-northwest down-plunge extension of Argus North between approximately 350 and 716 m vertical depth. The drilling continued to intersect the same broad style of altered and mineralized volcanic rocks seen in the shallower part of the zone. Hole MC26-298A is the deepest intersection reported to date and confirms that the mineralized system remains present more than 700 m below surface.

Significant Intervals from Argus North

• 1.1 g/t Au over 29.0 m, in drill hole MC26-268, including
  • 3.1 g/t Au over 6.0 m
• 3.5 g/t Au over 19.0 m, in drill hole MC26-271, including
  • 8.3 g/t Au over 6.6 m, including
    • 24.3 g/t Au over 1.0 m
• 3.5 g/t Au over 28.1 m, in drill hole MC26-274A, including
  • 5.3 g/t Au over 17.8 m, including
    • 23.1 g/t Au over 1.0 m, and including
    • 11.4 g/t Au over 2.0 m
• 2.9 g/t Au over 4.0 m, in drill hole MC26-293A, including
  • 8.1 g/t Au over 1.1 m
• 1.2 g/t Au over 5.0 m, in drill hole MC26-298A (716 m vertical depth), including
  • 2.2 g/t Au over 2.2 m
  • Note – This represents the deepest intersection to date at Argus North. Interval still shows silica/albite alteration with crackle brecciated intervals showing pyrite fracture filling to 3% pyrite.

Drilling continues to focus on extending the zone down plunge to the west-northwest with one drill rig.

Discussion of Argus Main Drill Results

Three holes stepped progressively deeper below previously reported Argus Main drilling. Each hole intersected multiple gold-bearing intervals, including broad zones approaching 100 m in drilled width and narrower higher-grade sections.

Significant Intervals from Argus Main

• 1.0 g/t Au over 93.0 m, in drill hole MC26-324, including
  • 2.0 g/t Au over 20.0 m, including
    • 9.8 g/t Au over 1.0 m, and
  • 0.9 g/t Au over 33.0 m, including
    • 3.0 g/t Au over 6.0 m, including
• 19.3 g/t Au over 0.7 m
• 0.8 g/t Au over 98.9 m, in drill hole MC26-317 (60m south-south-west of MC26-267), including
  • 1.1 g/t Au over 35.8 m, including
    • 2.7 g/t Au over 5.9 m
• 0.8 g/t Au over 59.9 m, in drill hole MC26-311 (110m south-southwest of MC26-267), including
  • 3.3 g/t Au over 10.3 m, including
    • 14.2 g/t Au over 0.9 m, AND
• 1.9 g/t Au over 11.6 m, including
  • 2.5 g/t Au over 6.8 m, AND
• 0.8 g/t Au over 30.3 m, including
  • 2.9 g/t Au over 5.0 m
  • Note – This represents the deepest intersection to date at Argus Main at approximately 400 m vertical depth.

The Argus Main zone has been defined to surface where high-grade surface channel and grab samples grade between 5.2 g/t Au and 14.7 g/t Au, and to approximately 400 m vertical depth. The style of alteration and mineralization at Argus Main is analogous to Argus North with moderate to strong albite-carb-silica, fracturing with local development of crackle breccia, hosted within mafic variolitic to pillowed volcanics, with 1-3% fine pyrite.

The Argus Main zone remains open along strike and at depth and one drill rig is currently dedicated to systematic expansion drilling along strike, and up and down the plunge of the zone.

Discussion of Northeast Target Drill Results

The five reconnaissance holes completed 250 m northeast of Argus Main tested a previously undrilled part of the projected Argus Fault corridor in a different package of mafic volcanic rocks. Two holes intersected gold over a strike length of approximately 100 m. While early-stage, these results show that mineralization is not limited to only a certain package of volcanic rocks that host the Argus Gold System and provide a clear target for follow-up drilling north and south of the initial intercepts.

Significant Intervals from Northeast Target

• 2.6 g/t Au over 7.3 m, in drill hole MC26-316, including
  • 8.8 g/t Au over 1.5 m
• 1.3 g/t Au over 5.7 m, in drill hole MC26-314, including
  • 2.2 g/t Au over 3.0 m

Ongoing 2026 Program

The Company continues to execute one of the largest fully funded gold exploration programs in the Abitibi, with 188 drill holes totalling ~75,000 m to date. Assays have now been released for 131 drill holes, with approximately 35,000 m remaining to be drilled in 2026.

The primary focus of the Program remains the continued expansion of the Argus Gold System, where drilling has identified two key styles of gold mineralization:

1. Steeply plunging, high-grade gold zones associated with northeast-trending fault corridors (D2 – controlling structures); and
2. Disseminated zones of low- to moderate-grade gold zones which surround and flank the high-grade intervals within the northwest-southeast trending permissive host mafic variolitic and fragmental volcanic rock stratigraphy (D1 – stratiform-style).

The Argus Gold System continues to demonstrate strong continuity of gold mineralization across multiple zones and host lithologies over a total strike length of approximately 1,400 m and a vertical extent exceeding 700 m. The Argus Zones remain open along strike, down-dip, and down-plunge, with mineralization also projecting to the near-surface in multiple locations. The higher-grade zones, such as Argus North and Argus Main, appear as steeply plunging shoots with an apparent periodicity of 400 m along strike within the host mafic variolitic volcanic unit, coinciding with the intersection with key northeast-trending mineralizing structures. These structures remain largely untested across the broader Pipestone corridor, where Onyx controls 8 km of prospective strike length, providing substantial room to test for additional mineralized centres. Management believes the combination of favourable host rocks, large-scale structural preparation, and the emerging high-grade plunging zones highlights the potential for additional discoveries across the Project, and the systematic testing of this corridor remains the primary focus for the Company.

The Company continues to operate four (4) diamond drill rigs with an anticipated end to the 110,000 m program by year end.

A 420 line-kilometre high-resolution drone magnetic survey has been completed over the Argus Gold System and the greater Pipestone corridor. Data processing is underway. Summer fieldwork also includes mapping, sampling and mechanical stripping of selected areas where mineralization is exposed or interpreted to project to surface.

The Company is fully funded with approximately $18 million in cash.

Figure 1 – Plan Map Highlighting Argus Zone Drill Holes Reported in this Release

 Figure 2 – Cross-Section Highlighting Argus Main Drill Holes Reported in this Release – Looking Northeast – 100m window

 Figure 3 – Longitudinal Section Highlighting Drill Holes Reported in this Release – Looking North – 1200 m window

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

Table 1 – Significant Assay Results Reported in this Release

Table 1 (Continued)

Table 1 (Continued)

*All intersections are reported as drilled width; true width is 60-90% of drilled width

A table of all drill collar details and significant assay intersections released to date can be found on the Company website at https://onyxgold.com/projects/munro-croesus-gold/.

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 4). 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 112 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.

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 – one of the most exciting new gold zones emerging in the camp. 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 discovery 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.