Onyx Gold Corp. announced gold results for the initial six drill holes from its ongoing, fully funded 3,000-meter ("m") Spring Drill Program (the "Program") at its Munro-Croesus Project ("Munro-Croesus" or the "Project") in the Timmins gold camp, Ontario. All six drill holes were completed at the recently discovered GM Vein, located 350 m from the past-producing Croesus Gold Mine, which yielded some of Ontario's highest-grade gold ever mined.

Drill results are provided in Table 1 and include: At the GM Vein, the first six drill holes have returned very encouraging results at an average vertical depth of 55 m, with visible gold observed in four of the six holes reported (MC24- 43/144/147/148). The GM Vein remains open for expansion. MC24-147, a follow-up hole completed down-dip from Hole MC23-132 (121.8 grams per tonne ("g/t") gold ("Au") over 0.9 m - See Company press release dated December 6, 2023), returned 26.09 g/t Au over 1.0 m, including 51.27 g/t Au over 0.5 m. MC24-143, a follow-up hole completed up-dip from Hole MC23-132, returned 7.39 g/t Au over 1.6 m in hole MC24-143, including 19.46 g/t Au over 0.4 m. A total of 16 short holes have now been completed across three 10m step-out fences on the near- surface GM Vein discovery.

Assay results for the remaining 10 drillholes will be released on an ongoing basis pending review and compliance with Company QA/QC protocols. The diamond drill rig has been moved to the bulk-tonnage Argus Zone located three kilometers west of the GM Vein. Approximately half of the program's meterage will be dedicated to expanding the Argus Zone beyond its current strike length of 525 m and 200-m thickness.

Highlighted Assay Results for GM Vein: 26.09 g/t Au over 1.0 m in hole MC24-147, including 51.27 g/t Au over 0.5 m; 7.39 g/t Au over 1.6 meters in hole MC24-143, including 9.46 g/t Au over 0.4 m; and 5.00 g/t Au over 1.3 meters in hole MC24-144, including 11.98 g/t Au over 0.3 m. The GM Vein was discovered in the 2023 fall drill program when drill hole MC23-132 intersected a 30-centimeter wide quartz vein with abundant visible gold that returned 363 g/t Au over 0.3 m. This intersection represents the single highest assay in the Company's drill hole database for the Project. The high-grade vein occurs within a broader zone of mineralization averaging 121.8 g/t Au over 0.9 m and was intersected approximately 60 m vertically below surface. This discovery represents an entirely new bonanza-grade quartz vein in a geological setting comparable to the mined-out, very high-grade Croesus vein, located 350 m to the southeast, along the prospective Croesus pillowed mafic flow.

Results reported are from the first six holes (MC24-143 to 148) drilled on 5-to-10-m spaced centres along 320 Azimuth on the same cross-section as hole MC24-132. All six holes intersected the quartz-carbonate vein, which was anticipated as either a discrete vein or a broader vein zone over 0.3-to-2.0-m widths. Visible gold was observed in four of six holes and appears to be associated with thin black wavy stylolites within the vein.

Highlights include 26.09 g/t Au over 1.0 m, in hole MC24-147, including 51.27 g/t Au over 0.5 m, 7.39 g/t Au over 1.6 m, in hole MC24-143, including 19.46 g/t Au over 0.4 m, and 5.00 g/t Au over 1.3 m, in hole MC24-144, including 11.98 g/t Au over 0.3 m. Discussion of the 2024 Spring Drill Program: The 3,000-m Program will see approximately 50% of the drilling allocated to the GM Vein to: expand the known high-grade gold mineralization around drill hole MC23-132 by determining a potential plunge control on the gold "shoots"; identify new, repeated "shoots" by targeting the GM Vein along strike; and test for a carbonaceous, sulfidic "flow top" breccia at the stratigraphic top of the unique Croesus. Flow along strike from the GM Vein discovery. This distinctive breccia hosts the higher-grade portion of the Croesus Vein and represents an attractive reducing environment for gold deposition.

The remaining 50% of the meterage will be dedicated to the Argus Zone, three kilometers west-northwest of the past-producing Croesus Gold Mine and immediately north of the Pipestone Fault. It is a broad zone of near-surface gold mineralization within the influence of the regional gold-bearing Pipestone Fault. The objective of planned drilling in the Argus Zone is to: follow up with 50-m step-out holes on the best intersection from the fall 2023 drilling (0.96 g/t Au over 27.6 m in drill hole MC23-140; expand the Argus Zone beyond the current strike length of 525 m and 200-m thickness through a series of 100-m step-out holes to the west towards the convergence of the Argus Zone with the regional Pipestone Fault; and test the continuity of the Argus Zone to the west in an area of structural complexity with a coincident airborne magnetic low and define the interpreted late cross-faulting that is expected to offset the Argus Zone and Pipestone Fault towards the south.

The Program is estimated to take six weeks to complete. To maximize sample sizes, all drilling in the GM Vein target will be completed with HQ-sized core. Drilling in the Argus Zone will be completed with NQ-sized core, as in previous drill programs. Assay results will be released on an ongoing basis pending review and meeting Company quality assurance and quality control protocols.