Drilling Successfully Identified High Grade At Munro-Croesus Project

VANCOUVER - Onyx Gold Corp. reported on gold results for the next 14 drill holes from its ongoing, fully funded 3,000-meter Spring Drill Program at its Munro-Croesus Project in the Timmins gold camp, Ontario. The 14 drill holes completed at the new GM Vein, located 350 meters (m) from the past-producing Croesus Gold Mine, which yielded some of Ontario's highest-grade gold ever mined. Drilling continues to intersect encouraging results from the GM Vein at an average vertical depth of 50-60 m with visible gold observed in four of the 14 holes (MC24-152/154/156/162). Drilling has now defined a higher-grade shoot plunging to the southwest and the GM Vein remains open for expansion in all directions.

Significant assay intersections include: 1) MC24-154, a follow-up hole completed 10 m southwest from Hole MC23-132 (121.8 grams per tonne (g/t) gold (Au) 0.9 m, returned 52.06 g/t Au over 0.5 m within a broader zone of 26.52 g/t Au over 1.0 m. 2) MC24-151, a follow-up hole completed 10 m northeast from Hole MC23-132, returned 20.44 g/t Au over 0.4 m within a broader zone of 10.97 g/t Au over 0.8 m. 3) MC24-152, a follow-up hole completed 20 m up-dip from Hole MC24-151, returned 32.31 g/t Au over 0.3 m within a broader zone of 7.68 g/t Au over 1.4 m. 4) MC24-156, a follow-up hole completed 5 m up-dip from Hole MC24-154, returned 15.52 g/t Au over 0.4 m.

A total of 20 holes totaling 1,713 m were drilled on the GM Vein in March and April 2024. Seventeen (17) short drill holes (MC24-143 to MC24-159) were completed across the GM Vein on three 10 meter-spaced drill fences. Two additional holes (MC24-160 and MC24-162) were completed 30 m down-plunge and 30 m up-plunge from the three main fences of holes. One hole, MC24-161, was drilled to the northeast to test for the prospective carbonaceous, sulfidic "flow top" breccia, which hosts the higher-grade portion of the Croesus Vein, 350 m to the southeast.

84% of drill holes (16 of 19 holes drilled to date) intersected mineralization greater than 0.5 g/t Au. Ten drill holes intersected mineralization over 10 g/t Au. The diamond drill rig is now testing the bulk-tonnage Argus Zone located three kilometers west of the GM Vein. The remaining program meterage will be dedicated to expanding the Argus Zone beyond its current strike length of 525 m and 200 m thickness. Given the encouraging results, the Program has been upsized by 10% to 3,300 m and will wind up shortly. Assay results will be released on an ongoing basis pending review and compliance with Company QA/QC protocols.

"We are very encouraged with the results from this year's spring program so far," said Brock Colterjohn, President & CEO. "Our drilling efforts have successfully defined a higher-grade shoot, and the GM Vein remains open for expansion in all directions. We look forward to further expanding this high-grade lens and exploring for similarly plunging zones with future drill programs.

We are now drilling over at the bulk-tonnage Argus zone target, with the objective of extending the zone further to the west. We've expanded the program by 10% to 3,300 meters, reflecting the positive results and our confidence in the project's prospects. Our commanding land position and wealth of opportunities for new discoveries provides the potential for Onyx to become the go-to explorer in the Timmins Camp. We are looking forward to reporting further assays as they become available."