Mr. Brock Colterjohn reports

ONYX GOLD EXPANDS MUNRO-CROESUS DRILL PROGRAM TO 110,000 METERS; ADDS FOURTH DRILL RIG

Onyx Gold Corp. has provided an update on its fully financed 2026 exploration program at its 100-per-cent-owned Munro-Croesus project, located 75 kilometres east of Timmins, Ont.

The company has expanded its continuing drill program from 75,000 metres to 110,000 metres and added a fourth drill rig, significantly increasing the pace of drilling across the project. The expanded program is designed to both accelerate growth of the Argus zones and systematically test multiple high-priority targets along the underexplored Pipestone fault and across the broader Munro-Croesus property.

Key program highlights and updates:

• Drill program expanded to 110,000 m, positioning Onyx among the most active gold exploration companies in Canada in 2026;
• Continuing year-round drilling with increased pace following addition of the fourth drill rig, with flexibility to adjust pace as results dictate;
• Of the 110,000-metre drill program, more than 50,000 m (135 holes) have been completed to date (May, 2025, to April 22, 2026), with approximately 60,000 m remaining to be drilled through year-end; 77 drill holes reported to date, with a steady pipeline of results to be released in batches as received;
• Strong treasury (approximately $22-million) with the expanded program fully financed and capacity for further growth;
• Demonstrated lateral and vertical continuity of gold mineralization at the Argus zones to over 1,400 m of strike length and to vertical depths exceeding 500 m from surface;
• Argus zones remain open in all directions, with mineralization projecting toward surface in multiple areas;
• Continuing work continues to define key structural and stratigraphic controls to the gold mineralization with potentially significant exploration implications along the eight kilometres of strike length of the Pipestone fault that Onyx controls and across the greater property;
• A 900-line-kilometre high-resolution drone magnetic survey is set to commence, aimed at refining targets across the Argus zones and the greater Pipestone fault corridor.

"Over the past year, we have rapidly advanced Munro-Croesus from a single discovery into what we now believe is a district-scale property capable of hosting several gold systems of different styles," stated Brock Colterjohn, chief executive officer. "With more than 50,000 metres already drilled and multiple zones demonstrating strong continuity, scale and expansion potential, we are now accelerating aggressively with a fourth drill rig and a 110,000-metre program -- one of the largest drill programs for a gold exploration company in Canada.

"Importantly, we are beginning to see a repeatable structural framework emerge across the Argus zones and along the Pipestone fault, which we believe will significantly improve our ability to systematically target higher-grade mineralization within a broader gold system. At the same time, we are unlocking multiple parallel discovery opportunities across our 109-square-kilometre land package, including high-grade vein targets and underexplored regional corridors.

"With a fully funded program, strong ongoing news flow and multiple catalysts ahead, we believe Munro-Croesus is evolving into one of the most compelling discovery stories in the Timmins camp."

2026 drill target priorities

Onyx's primary objective in 2026 is to continue stepout drilling at the Argus zones to define a gold system with meaningful scale. In parallel, the company has designed multiple work streams targeting different styles of mineralization across the project, each with potential to add meaningful ounces.

Argus zones

Argus North: Since its discovery in April, 2025, Argus North has rapidly evolved into a high-grade zone with over 250 m of strike length and strong vertical continuity from surface to approximately 400-metre depth. The deepest hole to date returned 73.2 m grading 2.4 grams per tonne gold, including 12.0 m grading 5.7 g/t Au and 6.1 m grading 12.4 g/t Au (see Jan. 13, 2026, news release). Coming drilling will focus on stepouts along strike and down plunge to further expand the zone.

Argus Main: Located 100 m south of Argus North, Argus Main represents a 900-metre-by-200-metre near-surface bulk-tonnage gold system with consistent 0.5- to 2.0-gram-per-tonne-gold mineralization and internal higher-grade zones. Recent drilling identified a new northeast-trending high-grade structure similar in characteristics to Argus North located 600 m to the northwest, returning 77.2 m grading 1.3 g/t Au, including 15.0 m grading 4.9 g/t Au (see March 31, 2026, news release). These results support a model where higher-grade zones have an apparent periodicity and can be systematically targeted within a broader bulk-tonnage system. Coming work will focus on expanding these structures and the overall footprint of mineralization.

Argus West and the Emerging Argus fault: The discovery of Argus West (MC25-213: 21.2 m grading 2.1 g/t Au; see Dec. 3, 2025, news release), located 250 m southwest of Argus North, highlights a newly defined structural corridor associated with the Argus fault, interpreted as a key control on mineralization. This opens a new exploration vector with potential for repetition of Argus-style mineralization to the west. Coming drill activities include testing the continuity of this zone and evaluating the broader structural corridor over several hundred metres of strike length and down to 300 m from surface.

Pipestone fault corridor

Recent structural modelling suggests that similar controlling northeast-trending structures extend across the Argus zones and along the regional Pipestone fault. Onyx controls eight km of strike extent of this highly prospective structural corridor, providing a district-scale exploration opportunity. The 2026 drill program will test multiple parallel and, most importantly, repeating structures along approximately five km of its strike length, targeting both high-grade and bulk-tonnage mineralization.

High-grade vein targets

The eastern portion of the Munro-Croesus property hosts numerous high-grade past-producing underground mines and gold targets associated with secondary structural features extending from Pipestone fault for several kilometres across the property. Following extensive land consolidation, Onyx is now the first company to systematically explore these targets under unified ownership. Key targets include the following.

Historic Croesus mine: Located on the property and three km east of the Argus zones, the Croesus gold mine produced some of the highest-grade gold ever mined in Ontario. Drilling by HighGold Mining in 2020 intersected 0.5 m grading 190.5 g/t Au, including 0.3 m grading 311.0 g/t Au in MC20-43, approximately five m above the old underground workings, and may represent a vein or a splay of the historic Croesus vein. No follow-up drilling has been completed.

GM vein: Discovery of a new blind high-grade vein in 2023 returned 0.3 m grading 363.0 g/t Au within a broader zone of 0.9 m grading 121.8 g/t Au in MC23-132 (see Dec. 6, 2023, news release). This high-grade quartz vein, located 350 m northwest of the past-producing Croesus gold mine, shares the same geological setting and a similar orientation as the historic Croesus vein and was discovered during systematic testing of the favourable Croesus mafic volcanic pillowed flow. The GM vein remains open for expansion in all directions, and its proximity to the historic Croesus gold mine, along with strong geological parallels, suggests the potential for further high-grade discoveries.

C-Zone: Located six km east of the Argus zones, the C-Zone was evaluated by mechanical stripping and channel sampling completed by Onyx Gold in the summer of 2025, and returned the highest-grade channel sample results to date at Munro-Croesus, including 0.62 m grading 124 g/t Au within 2.3 m grading 39.5 g/t Au from the newly exposed veins (see Jan. 6, 2026, news release). The C-Zone remains open along strike and at depth presenting strong potential for expansion through initial drill testing.

These targets provide near-surface, high-grade discovery potential complementary to the broader Argus system.

Regional upside -- underexplored 109-square-kilometre land package

The 109-square-kilometre Munro-Croesus land package remains largely underexplored. Planned drilling will test multiple regional targets both north and south of the Pipestone fault across geological settings analogous to the Argus zones and other gold deposits in the Timmins camp.

Webinar update

Onyx plans to host a webinar in early May with Mr. Colterjohn, president and chief executive officer, and Conor McKinley, vice-president of exploration, to provide a corporate update and outline the expanded 2026 exploration strategy. Further details will follow shortly.

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. This large, 100-per-cent-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 109 square kilometres 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 Corp.

Onyx Gold 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, Ont., 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-square-kilometre property situated just nine km from Discovery Silver's Hoyle Pond mine, and Timmins South, a 187-square-kilometre land package strategically positioned around the Shaw Dome structure, offering considerable 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 record of discovery, development and value creation, Onyx Gold is well financed and committed to delivering shareholder value through disciplined exploration, strategic growth and responsible resource development.

Ian Cunningham-Dunlop, PEng, executive vice-president for Onyx Gold, a qualified person as defined by Canadian National Instrument 43-101, has reviewed and approved the technical information contained in this release.

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