ONYX.V · 2025-10-07 12:00:00

Onyx Gold Defines Gold Mineralization Right at Surface at Argus North Channel samples up to 5.0 g/t Au over 4.0 m within 2.0 g/t Au over 21.3 m and step-out drilling up to 5.0 g/t Au over 8.6 m within 1.8 g/t Au over 37.8 m confirm the potential for a near-

Drill Results Exploration Programs

Onyx Gold Defines Gold Mineralization Right

at Surface at Argus North

Channel samples up to 5.0 g/t Au over 4.0 m within 2.0 g/t Au

over 21.3 m and step-out drilling up to 5.0 g/t Au over 8.6 m

within 1.8 g/t Au over 37.8 m confirm the potential for a near-

surface, road-accessible gold discovery

Vancouver, British Columbia--(Newsfile Corp. - October 7, 2025) -

Onyx Gold Corp.

(TSXV: ONYX)

(OTCQX: ONXGF)

Onyx

" or the "

Company

") is pleased to announce surface channel sampling and

drill results from the Company's ongoing 25,000 metre drill program (the "

Program

') at its 100% owned

Munro-Croesus Project ("

Munro-Croesus

" or the "

Project

"), located 75 km east of Timmins, Ontario.

Results are reported today for four (4) shallow step-out holes and a series of sawn channel samples of

new outcrop exposed by mechanical stripping near previously reported drill hole MC25-180 (

see

Company news release dated July 23, 2025

) which returned

4.0 meters ("m") of 5.9 grams per

tonne gold ("g/t Au") within 50.4 meters of 1.9 g/t Au

starting at 6.1 m downhole. Collectively, the

new results outline a significant zone of gold mineralization that comes right to surface, located just two

kilometres off Highway 101 (

Figures 1

Highlights

Drill Holes

60.8 m grading 1.2 g/t Au

, in drill hole MC25-200, including

3.0 m grading 5.9 g/t Au

37.8 m grading 1.8 g/t Au

, in drill hole MC25-202, including

8.6 m grading 5.0 g/t Au

37.5 m grading 1.2 g/t Au

, in drill hole MC25-204, including

10.2 m grading 2.4 g/t Au

Channel Samples

10.7 m grading 0.6 g/t Au

, including

3.1 m grading 7.4 g/t Au

, within, in Channel A

8.9 m grading 0.9 g/t Au

, including

2.8 m grading 1.6 g/t Au

, within in Channel B

21.3 m grading 2.0 g/t Au

, including

4.0 m grading 5.0 g/t Au,

within in Channel C

15.5 m grading 1.6 g/t Au

, including

6.5 m grading 2.8 g/t Au

, within in Channel D

7.4 m grading 4.9 g/t Au

, including

3.9 m grading 8.4 g/t Au

, within in Channel E

3.4 m grading 1.8 g/t Au

, including

1.0 m grading 4.0 g/t Au

, within in Channel F

7.4 m grading 4.9 g/t Au

, including

3.9 m grading 8.4 g/t Au

, within in Channel G

15.4 m grading 2.2 g/t Au

, including

2.0 m grading 8.4 g/t Au

, within in Channel H

Surface sampling and ongoing step-out drilling at Argus North continues to demonstrate

wide

intervals of promising gold mineralization over >100 meters of strike length

and

from

surface to >350 meters vertically

The Company has

completed 64 drill holes

(assays announced for 18 holes to date) completing

approximately 20,000 m

(80%) of the expanded 25,000 m Program.

"Argus North continues to deliver wide intervals of gold mineralization right from surface, just two

kilometres off the highway — a rare and highly attractive combination in the Timmins camp," said Brock

Colterjohn, President & CEO of Onyx Gold. "These results reinforce the potential for Argus North to

evolve into a significant, road-accessible gold system and, with the majority of assays from our fully

funded 25,000 metre program still pending, we are steadily building a clearer picture of the opportunity.

With the recent closing of our $20 million bought-deal financing and the upcoming close of our upsized

$6.4 million non-brokered financing with strategic investors, Onyx is well financed to maintain strong

news flow and advance exploration through 2026."

Discussion of 2025 Argus North Near-Surface Results

The Argus North Zone is located on the western half of the Munro-Croesus Project, approximately 150

metres north of the regional Pipestone Fault, a major structural corridor that hosts several significant gold

deposits in the Timmins camp. Discovery hole MC24-163, reported earlier this year, 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

). Argus North lies roughly 100 metres north of the east-

west trending Argus Main Zone, which represents a separate 750 m x 200 m near-surface bulk-tonnage

gold target (e.g., 1.0 g/t Au over 63.3 m and 0.5 g/t Au over 136 m).

Gold mineralization at Argus North is distinguished by broad zones (50 m to over 100 m) of +1 g/t Au

mineralization containing multiple continuous higher-grade sub-intervals. Notable recent high-grade

intercepts include

17.0 m grading 5.3 g/t Au

in hole MC25-168,

18.7 m grading 5.2 g/t Au

in MC25-

171,

5.2 m grading 5.1 g/t Au

and

6.6 m grading 4.2 g/t Au

in MC25-178,

4.0 m grading 6.6 g/t Au

in MC25-179,

4.0 m grading 5.9 g/t Au

in MC25-180, and

4.0 m grading 4.6 g/t Au

in MC25-177. For

context, intercepts of this grade and thickness, in addition to the broad zones of +1 g/t Au mineralization,

compare favorably with those reported from other major gold deposits in the Timmins camp,

underscoring the potential significance of Argus North as a material new gold discovery in the district.

Geologically, the high-grade sub-intervals are closely associated with zones of strong albitization and

silicification, pyritic stringers, and localized porphyritic intrusions within variolitic basalt and volcanic

breccias. This combination of alteration and structural preparation is interpreted to be a key control on

gold deposition. Drilling to date demonstrates excellent vertical continuity of mineralization, traced from

surface to over 350 meters depth, with the system remaining open along strike, down-dip and down-

plunge.

Mechanized stripping and power washing at Argus North over a 15 m by 80 m area has now exposed an

alternating stratigraphic sequence of massive, variolitic, fragmental, and pillowed basalts intruded by two

feldspar porphyry dykes. Mineralization is hosted primarily within fragmental basalt units which represent

the main lithology of the stripped area, and correlates well with observations from drill core. The

mineralization is broadly disseminated pyrite within the fragmental basalts, with higher Au grades

associated with 2-5% disseminated and stringer pyrite, strong albite alteration, and locally feldspar

porphyry dykes.

One hundred and seventy-four (174) individual channel samples averaging 1 m in length were collected

in total from 11 channels crosscutting main structures and volcanic stratigraphy.

Details of the channel sample lines reported in this news release are shown in

Figures 1

and

Table 1

Details for drill hole assay reported in this news release are shown in

Figures 2 and 3

and

Table 2

Results for a fourth hole, MC25-203, are still pending.

The Company has completed 64 drill holes (assays announced for 18 holes to date) completing

approximately 20,000 m (80%) of the expanded and fully funded $10 M, 25,000 m Program.

Figure 1 - Plan Map Highlighting Argus North Zone Channel Samples Reported in this Release