Mr. Brock Colterjohn reports

ONYX GOLD MOBILIZES DRILL RIG AND OUTLINES TARGETS FOR 10,000-METER TIMMINS SPRING DRILL PROGRAM

Onyx Gold Corp. has planned a 10,000-metre spring drill program at its Timmins, Ont., properties. The primary focus of the program is to follow up on the recently reported Argus North discovery at the company's 100-per-cent-owned Munro-Croesus project, located 75 kilometres east of Timmins, Ont. To date, this new zone of wide high-grade mineralization has been tested by a single drill hole, MC24-163, which intersected 3.4 grams per tonne gold over 69.6 metres, including a high-grade subzone of 13.9 grams per tonne gold over 9.5 metres (see news release dated April 10, 2025).

"The initial results from Argus North point to a potentially significant new zone of high-grade gold mineralization in a proven district," said Brock Colterjohn, president and chief executive officer. "Mineralization at Argus North is open in all directions and our upcoming drill program is designed to rapidly evaluate and expand upon this discovery. A drill rig has just been delivered to site and we are excited to be kicking off the follow-up drill program. Upon close of the recently announced and upsized $11-million financing, the company will have considerable flexibility to expand the size of the drill program to follow up on further success with the drill bit."

Discussion of planned 10,000-metre spring drill program

Immediate follow-up plans include an initial phase 1 program of stepout drilling to extend the Argus North mineralization up dip to surface, downdip to depth, and along strike to both the east and west. Plans include re-entering and extending drill hole MC23-163 to assess the full breadth of the Argus North mineralizing system and drill holes MC23-140 and MC24-164, both of which stopped short of the downdip projection of the Argus North zone.

Phase 1 follow-up drilling is designed on nominal 50-metre-spaced stepouts with the objective of expanding the new discovery while concurrently gaining a better understanding on the zone's orientation, shape and geological controls. Drilling will start on the same cross-section as discovery drill hole MC24-163, followed by fences of similarly spaced holes on cross-sections 50 metres to the east and west. Phase 2 follow-up will include larger stepouts along strike and to depth.

At a larger scale, historical and recent trenching and sampling within the same key prospective mafic variolitic volcanic units and along the Pipestone fault to both the west and east of Argus North and Argus Main suggests multikilometre scale potential along trend completely untested by any drilling to date. A portion of the planned program metreage is designed to target this larger-scale potential, including first-ever drilling in the Argus West area.

In addition to the drilling at Munro Croesus, approximately 1,500 metres of the 10,000-metre program is committed to reconnaissance drilling at the 140-square-kilometre Golden Mile property, targeting a key northern splay of the Pipestone fault approximately 50 kilometres to the west. This drilling will be completed with a separate drill rig to the one that is dedicated to Argus North drilling at Munro Croesus. Golden Mile is located nine kilometres northeast of Discovery Silver's multimillion-ounce Hoyle Pond deposit in Timmins.

Description of the Argus Main zone and Argus North discovery

The Argus Main zone is located three kilometres northwest of the past-producing Croesus gold mine and represents a near-surface, bulk-tonnage target with 0.1 gram per tonne to greater than 2.0 grams per tonne gold over a 750-metre-by-200-metre area. Argus Main is hosted by silica-albite-pyrite-specularite-altered mafic variolitic volcanic rocks situated immediately north of the Pipestone fault, a major structural corridor known to host significant gold deposits, including Mayfair Gold Corp.'s 4.4-million-ounce Fenn-Gib deposit, located just six kilometres away.

Drilling at Argus Main in 2024 returned a highlight of 1.0 gram per tonne gold over 63.0 metres in drill hole MC24-166, including 2.2 grams per tonne gold over 17.4 metres (see the company's news release dated June 17, 2024). Overall drill results to date have shown improving gold grade and mineralized widths as the east-west-trending Argus Main zone is tracked westward.

Argus North is located approximately 100 metres north of the Argus Main trend and approximately 150 to 200 metres vertically below surface. This zone has only been intersected by one drill hole to date, with MC24-163 encountering a 70-metre interval of high-grade mineralization within strongly albite- and silica-altered mafic variolitic volcanics, hosting 3 per cent to 10 per cent fine pyrite stringers, with local visible gold. MC24-163 returned a very encouraging 3.4 grams per tonne gold over 69.6 metres, including 13.9 grams per tonne gold over 9.5 metres, with consistent gold values throughout, highlighting both the continuity and strength of the mineralization in this newly identified area. Argus North is interpreted to be near-vertical and sub-parallel to the east-west-trending Argus Main. Argus North is open in all directions, including to surface.

About the Timmins area gold properties

Onyx Gold owns 100 per cent of each of its three Timmins properties. The Munro-Croesus gold project is located approximately 75 kilometres east of Timmins, proximal to the Porcupine-Destor and Pipestone faults, and approximately two kilometres northwest and along trend of Mayfair Gold's multimillion-ounce Fenn-Gib gold deposit. Mining occurred intermittently at Munro-Croesus between 1915 and 1936. The 140-square-kilometre Golden Mile property is located nine kilometres northeast of Newmont's multimillion-ounce Hoyle Pond deposit in Timmins. The Timmins South 187-square-kilometre property is located to the south and southeast of Timmins and surrounds the Shaw dome structure.

About Onyx Gold Corp.

Onyx Gold is an exploration company focused on well-established Canadian mining jurisdictions, with assets in Timmins, Ont., and Yukon. The company's extensive portfolio of quality gold projects in the greater Timmins gold camp includes the Munro-Croesus gold property, renowned for its high-grade mineralization, plus two additional earlier-stage, large exploration properties, Golden Mile and Timmins South. Onyx Gold also controls four properties in the Selwyn basin area of Yukon, which is currently gaining significance due to recent discoveries in the area. Onyx Gold's experienced board and senior management team are committed to creating shareholder value through the discovery process, careful allocation of capital and environmentally/socially responsible mineral exploration.

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

We seek Safe Harbor.