Onyx Gold Drills 2.4 g/t Gold Over 73.2 Meters Including 12.4 g/t Gold Over 6.4 Meters in Deepest Intersection to Date at Argus North, Munro-Croesus Project Increase in Higher-Grade Assays Observed as System is Tracked to Depth with

January 13^th, 2025 NR# 02-2026

NEWS RELEASE

Onyx Gold Drills 2.4 g/t Gold Over 73.2 Meters Including 12.4 g/t Gold Over 6.4 Meters in Deepest Intersection to Date at Argus North, Munro-Croesus Project

Increase in Higher-Grade Assays Observed as System is Tracked to Depth with Seven Samples Assaying >20 g/t in Holes MC25-242 and 243, Including Up to 133.7 g/t Gold over 0.9 Meters

Vancouver, BC – January 13^th, 2026 – Onyx Gold Corp. (“Onyx” or the "Company") (TSX-V: ONYX, OTCQX: ONXGF) is pleased to announce additional drill results from the Company’s ongoing drill program (the “Program”) at its 100%-owned Munro-Croesus Project (“Munro- Croesus” or the “Project”), located 75 km east of Timmins, Ontario (Figure 4). Today’s results are for eight (8) drill holes at the Argus North Zone (“Argus North”), highlighted by drill holes, MC25-242 and MC25-243, which are oriented perpendicular to northeast-trending structures that are interpreted to focus higher-grade mineralization.

Drill Highlights

• Drill hole MC25-243 intersected 37.6 meters (“m”) grading 1.1 grams per tonne gold (“g/t Au) and a new second deeper intersection of 73.2 m grading 2.4 g/t Au that expands the thick zone of >2 g/t Au Argus North mineralization 50m along strike and to depth, and, more importantly, confirms the presence of strong mineralization west of a

north-south fault, opening-up significant down-plunge expansion potential.

• High-grade sub-intervals within the 73.2 m intersection in drill hole MC25-243 include:
  • 12.0 m grading 5.7 g/t Au, including 3.0 m grading 17.7 g/t Au, and
  • 6.1 m grading 12.4 g/t Au, including 2.5 m grading 21.2 g/t Au.
• Drill hole MC25-242 intersected two separate high-grade intervals that include:
  • 1.8 m grading 67.3 g/t Au, including 0.9 m grading 133.7 g/t Au, and
  • 25.7 m grading 5.0 g/t Au, including 10.4 m grading 9.3 g/t Au, including 0.8 m

grading 33.3 g/t Au.

• Abundant visible gold (“VG”) was observed within the high-grade intervals in drill hole MC25-242 that returned 133.7 g/t Au over 0.9 m from 227.2-228.1 m and between 259.0- 259.8m that returned 10.8 g/t Au over 0.8 m.
• An increase in higher-grade assays has been observed as the system has been tracked to depth with seven (7) individual samples assaying >20 g/t Au in holes MC25-242 (three assays > 20 g/t Au) and MC25-243 (four assays > 20 g/t Au).
• Ongoing drilling at the Argus North, Main and West discoveries has defined broad zones of gold mineralization over a total strike length of 900 m and from surface to >400 m vertically. All the Argus Zones remain open along strike, down-dip, and down-plunge.
• The Company has completed 100 drill holes to date, totalling >35,000 m as part of its 75,000 m Phase I/II/III drill program. Assays have now been announced for 61 holes.
• With $27 million in the treasury, the Company remains fully funded to continue advancing its 2026 exploration programs.

“Our latest results significantly expand the Argus North Zone and represent some of the strongest grades we have drilled yet, highlighting the increased potential for continuous high-grade mineralization at Argus North,” stated Brock Colterjohn, CEO. “We are particularly encouraged to document thick zones of strong mineralization west of the north-south fault, which clearly demonstrates the system is alive and well to the west and suggests grades increasing at depth. We are excited to continue testing the Argus North gold system to the west and down-plunge.”

“The higher-grade sub-intervals above 10 g/t Au are the most numerous we have intersected to date and the more abundant visible gold indicates we are intersecting a more fertile part of the system,” said Conor McKinley, Vice President of Exploration, “These results show that mineralization is becoming more predictable and repeatable as our geological model continues to improve. As we continue to step out on this new mineralization, we will evaluate if and how it is related to the Argus West discovery 160 meters to the southwest.”

Discussion of Argus North Drill Results

The Argus North Zone is located on the western half of the Munro-Croesus Project, approximately 150 m north of the regional Pipestone Fault, a major structural corridor that hosts several significant gold deposits in the Timmins camp. The discovery hole at Argus North, MC24-163, reported in April 2025, returned 69.6 m grading 3.4 g/t Au, including 34.5 m grading 5.4 g/t Au and 9.5 m grading 13.9 g/t Au (see Company news release dated April 10, 2025).

Gold mineralization at Argus North is distinguished by both broad zones (50 m to over 100 m) of +1 g/t Au mineralization containing multiple continuous higher-grade sub-intervals. The highergrade sub-intervals are closely associated with zones of strong albitization and silicification, pyritic stringers, and localized porphyritic intrusions within variolitic basalt and volcanic breccias cut by dominant steeply dipping, northeast-trending faults and associated fractures. This combination of alteration and structural preparation is interpreted to be a key control on gold deposition.

Results reported today include those from eight (8) infill and step-out drill holes completed at the Argus North as described below.

Western Extension

Two drill holes, MC25-242 and MC25-243, on the same cross-section were part of the Company’s current strategy of northwesterly-directed holes drilled perpendicular to the apparent northeasttrending structural corridor at Argus North.

Drill hole MC25-243 returned a very encouraging intersection of 37.6 m grading 1.1 g/t Au and a new second deeper intersection of 73.2 m grading 2.4 g/t Au. The lower zone now expands the Argus North Zone by more than 50 m to 225 m strike length and > 400 m vertical depth and likely represents a minor fault offset of Argus North across the late, north-south trending Barton Creek Fault. Highlights include:

• 1.8 m grading 67.3 g/t Au, in drill hole MC25-242, including
  • 0.9 m grading 133.7 g/t Au, and
• 25.7 m grading 5.0 g/t Au, including
  • 10.4 m grading 9.3 g/t Au, including
    • 0.8 m grading 33.3 g/t Au
• 72.8 m grading 0.8 g/t Au, in drill hole MC25-243, including
  • 37.6 m grading 1.1 g/t Au, including
    • 3.1 m grading 3.7 g/t Au, and
• 73.2 m grading 2.4 g/t Au, including
  • 12.0 m grading 5.7 g/t Au, including
    • 3.0 m grading 17.7 g/t Au, and
  • 6.1 m grading 12.4 g/t Au, including
    • 2.5 m grading 21.2 g/t Au

Abundant VG was observed within the high-grade intervals in drill hole MC25-242 that returned 133.7 g/t Au over 0.9 m from 227.2-228.1 m (Plate 1) and 10.2 g/t Au over 0.8 m from 259.0- 259.8m (Plate 2). The VG appears associated with albite-silica-carbonate-pyrite vein breccia and flow breccia within variolitic basalt.

Three drill holes, MC25-201/205/208, were drilled earlier in the program from north to south to target the same area, 100m west of the discovery hole MC24-163, and appear to have drilled beneath the higher-grade plunge of the Argus North Zone and returned anomalous gold values.

2) Down-Dip Extension

Three drill holes, MC25-206/207/209, were drilled 120-150 m below the Argus North discovery hole MC24-163 to infill and extend mineralization down-dip and returned encouraging results in drill holes MC25-209 and MC25-207 as follows:

• 16.4 m grading 2.6 g/t Au, in drill hole MC25-209, including
  • 8.9 m grading 4.5 g/t Au, including
    • 3.0 m grading 9.6 g/t Au
• 21.0 m grading 0.7 g/t Au, in drill hole MC25-207, including
  • 2.0 m grading 3.6 g/t Au

Summary of Argus North Results

Drilling to date at Argus North and Argus Main continues to demonstrate excellent vertical continuity of gold mineralization over a total strike length of 900 m and to over 400 m vertical depth. The higher-grade gold mineralization appears to plunge west-northwest (68 degrees towards 289 degrees azimuth) based on drill hole assays and structural modelling (Figures 1/2/3).

The Argus North Zone remains open along strike, down-dip, and down-plunge, and the opportunity to expand the zone through ongoing drilling is considered excellent.

Details for drill hole assays reported in this news release are shown in Figures 1/2/3 and in Table 1.

Update on 2026 Winter Drill Program at Munro-Croesus

The Company resumed its 75,000-m Phase I/II/III drill program (the “Program”) at Munro-Croesus in early January to continue following up on encouraging gold intersections from its Argus North and West discoveries, as well as testing several high-value regional targets.

The Company has completed 100 drill holes to date, totalling >35,000 m with assays announced for 61 holes.

Plate 1 – Patches of Visible Gold within Albite-Silica-Carbonate-Pyrite Flow Breccia in Variolitic Basalt in Drill Hole MC25-242 at 227.7m down-hole.

Plate 2 – Patches of Visible Gold within Albite-Silica-Carbonate-Pyrite Vein Breccia in Variolitic Basalt Flow in Drill Hole MC25-242 at 259.5m down-hole.

Table 1 – Significant Assay Results from the Latest Drilling Completed at the Argus North Zone

*Intersections are reported as drilled width; true width is unknown.

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

Figure 2 – Longitudinal-Section Highlighting Argus North Zone Drill Holes Reported in this Release

Figure 3 – Cross-Section Highlighting Argus North Zone Drill Holes Reported in this Release – Looking Northeast

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