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Onyx Gold Expands Emerging High-Grade Corridor at Argus Main Drilling Continues to Define Multiple Broad Gold Zones Across the Expanding Argus System Join Onyx’s Exploration and Technical Webinar Today at 10:00am PT/1:00pm ET

Drill Results

Onyx Gold Corp.

405 - 375 Water Street,

Vancouver, BC, V6B 5C6

TSXV: ONYX

OTCQX: ONXGF

May 14th, 2026 NR# 11-2026

Onyx Gold Expands Emerging High-Grade Corridor at Argus Main

Drilling Continues to Define Multiple Broad Gold Zones Across the Expanding

Argus System

Join Onyx’s Exploration and Technical Webinar Today at 10:00am PT/1:00pm ET

Vancouver, BC – May 14th, 2026 – Onyx Gold Corp. (“Onyx” or the " Company") ( TSX-V:

ONYX, OTCQX: ONXGF) is pleased to report new drill results from its fully-funded 110,000-meter

drill program (the “Program”) at the 100%-owned Munro-Croesus Project (“Munro-Croesus” or

the “Project”), located 75 km east of Timmins, Ontario (Figure 4).

Today’s results from 18 drill holes, including two (2) drill holes on the Argus Main Zone (“ Argus

Main”) and 16 drill holes on the Argus North Zone (“ Argus North”), continue to expand gold

mineralization at the Company’s rapidly growing Argus discovery area, where drilling is outlining

a gold system extending over 1.4 kilomet ers (“km”) of strike length and more than 500 met ers

(“m”) vertically. The latest drilling continues to support the Company’s interpretation that

northeast-trending structural corridors are controlling higher-grade gold mineralization across the

Argus Zones, and potentially along multiple kilometers of the Pipestone Fault corridor.

The key results include two (2) additional drill holes from the emerging Argus Main target area,

where drilling continues to define broad zones of gold mineralization containing higher -grade

intervals similar to those seen at Argus North, located approximately 600 metres to the northwest.

These two drill holes follow up on the two discovery holes, MC26 -267 and MC26 -270, which

intersected an Upper and Lower Zone with intercepts of 99.5 m of 1.2 grams per tonne gold

(“g/t Au”) (Lower Zone) in drill hole MC26 -267, and 77.2 m grading 1.3 g/t Au (Lower Zone) in

MC26-270 (See Company news release dated March 31, 2026).

Onyx will be hosting an exploration and technical webinar today, May 14, 2026, at 10:00am PT /

1:00 pm ET to provide an in-depth update on the Company’s ongoing and expanded 110,000 m

drill program at Munro-Croesus, including the results found in this news release.

Online registration and participation details may be found at the following link:

https://my.demio.com/ref/YE0MQWQjKU2lb7y4

Highlights from Argus Main

• 69.9 m grading 0.7 g/t Au (Upper Zone) in drill hole MC26-288, including 16.5 m grading

2.1 g/t Au, and a second deeper intersection of 43.0 m grading 0.3 g/t Au (Middle Zone), and

a third deeper intersection of 58.5 m grading 0.6 g/t Au (Lower Zone), including 12.3 m

grading 1.8 g/t Au

• 126.2 m grading 0.3 g/t Au (Upper Zone) in drill hole MC26-292, including 6.0 m grading 1.2

g/t Au, and a second deeper intersection of 40.7 m grading 1.3 g/t Au (Middle Zone),

including 5.8 m grading 5.8 g/t Au , and a third deeper intersection of 120.2 m grading 0.4

g/t Au (Lower Zone), including 18.5 m grading 1.3 g/t Au

• Three stacked mineralized zones intersected in both drill holes from near -surface to

approximately 400 m depth , with total cumulative downhole widths of 287.1 m of

mineralization in MC26-292 and 171.4 m of mineralization in MC26-288

• The new drill holes extend mineralization a further 40 m northeast from previously reported

discovery holes MC26-267 and MC26-270

• Mineralization at Argus Main appears linked to high-grade surface channel and grab samples

grading between 5.2 g/t Au and 14.7 g/t Au over a 35 x 30 m area

• Argus Main remains open along strike and at depth with one drill rig dedicated to

systematic expansion drilling

Highlights from Argus North Drilling

• 28.0 m grading 1.6 g/t Au (from surface), in drill hole MC25-248, including

o 2.0 m grading 6.5 g/t Au, AND

• 42.0 m grading 1.8 g/t Au, including

o 4.0 m grading 8.0 g/t Au

• 42.0 m grading 1.4 g/t Au (from surface), in drill hole MC25-251, including

o 7.8 m grading 3.5 g/t Au, AND

• 45.9 m grading 1.4 g/t Au, including

o 19.0 m grading 2.6 g/t Au, and including

o 4.0 m grading 7.2 g/t Au

• 48.9 m grading 1.2 g/t Au, in drill hole MC25-238, including

o 2.0 m grading 2.9 g/t Au

• 34.8 m grading 1.2 g/t Au, in drill hole MC26-266, including

o 12.0 m grading 2.4 g/t Au

• Argus North continues to deliver broad zones of gold mineralization from surface to depth,

reinforcing the expansion potential of the zone and the greater Argus mineralized corridor

“These latest results continue to demonstrate the growing scale and continuity of the Argus

system and further validate our interpretation that northeast -trending structures are controlling

higher-grade gold mineralization across multiple zones,” stated Br ock Colterjohn, President &

CEO. “What is particularly exciting is that Argus Main is beginning to show characteristics similar

to Argus North, with broad mineralized envelopes containing higher -grade intervals associated

with these structures. With four rigs active and more than 50,000 m still to drill this year, we believe

we are still in the early stages of unlocking the broader potential of the system along the Pipestone

Fault corridor.”

Update on the Argus Zones and the Program

The Company continues to execute one of the largest fully funded gold exploration programs in

the Timmins camp, with 145 drill holes totalling ~60,000 m to date. Assays have now been

released for 95 drill holes, with approximately 50,000 m remaining to be drilled in 2026.

The primary focus of the Program remains the continued expansion of the Argus Zones, where

drilling has identified two key styles of gold mineralization:

1) Steeply plunging, high-grade gold zones associated with northeast-trending fault corridors (D2

– controlling structures); and

2) Disseminated zones of low- to moderate-grade gold zones which surround and flank the high-

grade intervals within the northwest -southeast trending permissive host mafic variolitic and

fragmental volcanic rock stratigraphy (D1 – stratiform-style).

The Argus Zones remain open along strike, down-dip, and down-plunge, with mineralization also

projecting to the near-surface in multiple locations. Notably, the higher-grade zones such as Argus

North and Argus Main show an apparent periodicity of 400 m along strike within the host mafic

variolitic volcanic unit, coinciding with the intersection with northeast -trending mineralizing

structures

Ongoing geological and geophysical work continues to refine the controls on gold mineralization

along the Pipestone Fault corridor, where Onyx controls more than 8 km of strike length in one of

the most prospective yet underexplored portions of the Timmins gold camp.

A 900 line -km high -resolution drone magnetic survey is underway, aimed at refining targets

across the Argus Zones and the greater Pipestone Fault corridor. The Company is f ully funded

with approximately $20 million in cash.

The Geological Setting of the Argus Zones

The Argus Zones are located on the western half of the Munro -Croesus Project, approximately

3 km northwest of the historic Croesus Gold Mine and immediately north of the regional Pipestone

Fault, a major structural corridor host to many of the significant gold deposits in the Timmins camp

(Figure 1). Following a multi-year consolidation effort, Onyx now controls over 8 km of strike

extent of the Pipestone Fault , most of which remains undrilled or has not seen any modern

exploration. Gold mineralization is hosted within volcanic rocks of the Kidd-Munro assemblage

across all Argus Zones.

The Argus North Zone is situated 150 m north of the Pipestone Fault and is distinguished by

both broad zones (50 m to over 100 m) of +1 g/t Au mineralization containing wide zones of higher-

grade mineralization (+5 g/t Au) . The higher -grade sub-intervals are associated with zones of

strong albitization and silicification, pyritic stringers, and localized porphyritic intrusions within

mafic variolitic basalt and volcanic breccias cut by dominant moderate to steeply dipping,

northeast-trending faults and associated fractures. This combination of host lithology, alteration

and structural preparation is interpreted to be a key control on gold deposition. The discovery

hole, MC24-163, was reported last year, and 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).

The Argus Main Zone lies ~100 m south of Argus North and represents a separate, broad east-

west trending, 900 m x 200 m near-surface bulk-tonnage gold target. The best surface expression

of the Argus Main Zone is stripped of overburden and consists of 10 grab and channel samples

grading between 5.2 g/t Au and 14.7 g/t Au , within a 35 x 30 m area. Gold mineralization is

associated with mafic variolitic volcanic flows that are strongly albite - and silica-altered and cut

by east-northeast-trending pyritic veinlets within a broader halo of carbonate alteration and local

development of specular hematite. Highlights from past drilling include 63.3 m grading 1.0 g/t

Au, including 17.4 m grading 2.2 g/t Au in MC24-166 (see Company news release dated June

17, 2024), 62.8 m grading 0.8 g/t Au within 136.0 m grading 0.5 g/t Au in MC22-110 (see

Company news release issued dated May 9, 2022), 59.7 m grading 1.0 g/t Au, including 18.4 m

grading 2.0 g/t Au in MC25-255 (see Company news release issued dated February 18, 2026 )

and 27.6 m grading 1.0 g/t Au in MC23-140, and Figures 1, 2, and 3).

The Argus West Zone is located ~250 m west of Argus North, along the recently delineated

‘Argus Fault’, a key northeast-trending, moderately-to-steeply NW-dipping structure that appears

to play an important role as a locus for gold mineralization. Drill hole MC25-213 returned 21.2 m

grading 2.1 g/t Au (with local visible gold) starting at 9.8 m downhole within strongly albite-altered

mafic variolitic volcanics with a moderate crackle brecciation, and fine -grained disseminated to

fracture-controlled pyrite in the structural hanging wall to the Argus Fault (see Company news

release dated December 3, 2025). Drill hole MC25-199, located a further 180 m to the southwest,

intersected 14.0 m grading 1.0 g/t Au hosted by fine -grained metasedimentary rocks of the

Porcupine Group, in the structural footwall to the Argus Fault.

Discussion of Argus Main Drill Results

Results reported today include those from 18 drill holes, including two (2) additional drill holes

from the new Argus Main target, MC26-288 and MC26 -292, which follow -up on previously

reported assay results in drill holes MC26-267 (4.9 g/t gold over 15.0 meters within 1.3 g/t Au

over 77.2 m) and MC26-270 (2.9 g/t Au over 12.5 m within 1.2 g/t Au over 99.5 m), targeted a

northeast-trending fault in the eastern section of the Argus Main Zone.

The drilling reported today extends the gold mineralization 40m further to the northeast with drill

holes, MC26-288 and MC26-292, collared 50 m apart on the same cross -section, intersecting

three broad zones of gold mineralization located near-surface to 300 m below surface (Figures 1,

2 and 3).

Highlights from Argus Main include:

• 69.9 m grading 0.7 g/t Au (Upper Zone), in drill hole MC26-288, including

o 16.5 m grading 2.1 g/t Au, including

▪ 3.9 m grading 6.0 g/t Au, including

➢ 1.9 m grading 10.1 g/t Au, AND

• 43.0 m grading 0.3 g/t Au (Middle Zone), AND

• 58.5 m grading 0.6 g/t Au (Lower Zone), including

o 12.3 m grading 1.8 g/t Au, including

▪ 6.9 m grading 2.7 g/t Au

• 126.2 m grading 0.3 g/t Au (Upper Zone), in drill hole MC26-292, including

o 6.0 m grading 1.2 g/t Au, AND

• 40.7 m grading 1.3 g/t Au (Middle Zone), including

o 5.8 m grading 5.8 g/t Au, including

▪ 1.0 m grading 15.0 g/t Au, AND

• 120.2 m grading 0.4 g/t Au (Lower Zone), including

o 1.8 m grading 3.7 g/t Au, and including

o 18.5 m grading 1.3 g/t Au, including

▪ 3.0 m grading 4.7 g/t Au

These higher-grade intersections are interpreted to be the depth extension of the h igh-grade

mineralization at surface (10 grab and channel samples grading between 5.2 g/t Au and 14.7 g/t

Au within a 35 x 30 m area).

Details for drill hole assays reported in this news release are shown in Figures 1/2/3 and Table 1.

Discussion of Argus North Drill Results

Sixteen (16) drill holes were completed to infill and step -out along strike, down -dip, and down-

plunge at the Argus North to continue to investigate the potential of the mineralizing system within

the key host mafic variolitic volcanic sequence.

The drill holes were directed to the northwest across the now well-defined northeast-trending

structural corridor over a distance of 300 m and also targeted the west-northwest plunging higher-

grade core of Argus North. Highlights include drill holes MC25 -248 and MC25 -251 which

intersected mineralization at surface followed by a second lower zone, and drill holes MC25-238

and MC26-266 which continue to extend the zone down-plunge to the southwest.

Northeast Strike Extension

• 28.0 m grading 1.6 g/t Au (from surface), in drill hole MC25-248, including

o 2.0 m grading 6.5 g/t Au, AND

• 42.0 m grading 1.8 g/t Au, drill hole MC25-248, including

o 2.0 m grading 5.2 g/t Au, and including

o 12.0 m grading 4.0 g/t Au, including

▪ 4.0 m grading 8.0 g/t Au

• 42.0 m grading 1.4 g/t Au (from surface), in drill hole MC25-251, including

o 7.5 m grading 1.9 g/t Au, and including

o 7.8 m grading 3.5 g/t Au, AND

• 45.9 m grading 1.4 g/t Au, in drill hole MC25-251, including

o 19.0 m grading 2.6 g/t Au, and including

o 4.0 m grading 7.4 g/t Au

Southwest Strike Extension

• 48.9 m grading 1.2 g/t Au, in drill hole MC25-238, including

o 2.0 m grading 2.9 g/t Au

• 34.8 m grading 1.2 g/t Au, in drill hole MC26-266, including

o 2.4 m grading 3.3 g/t Au, and including

o 12.0 m grading 2.4 g/t Au

• 13.0 m grading 1.7 g/t Au, in drill hole MC26-281, including

o 4.0 m grading 4.5 g/t Au

• 9.2 m grading 2.0 g/t Au, in drill hole MC26-286, including

o 1.2 m grading 8.4 g/t Au

The Argus Zones continue to show excellent lateral and vertical continuity of gold mineralization

within a variety of host lithologies over a total strike length of 1,400 m and a vertical depth of more

than 500 m. The Argus Zones remain open along strike, down -dip, and down -plunge, and the

opportunity to expand the zones through ongoing drilling is considered excellent. There is also an

apparent periodicity to the higher-grade zones of 400 m along strike within the host mafic variolitic

volcanic unit, and the Company is targeting offsets within this unit with associated magnetic lows

along strike to the southeast with one drill rig.

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 (Figure 4). This large, 100%-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 1 12 km2 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.

Table 1 – Significant Assay Results for Argus North Drill Holes Reported in this Release

Target From To Length Au

Drill Hole (m) (m) (m) (g/t)

Argus North

MC25-227 39.5 84.0 44.5 0.7

Including 39.5 56.5 17.0 1.2

Including 39.5 47.0 7.5 2.1

And Including 53.3 54.4 1.1 1.2

And Including 68.5 72.5 4.0 1.3

And 136.0 154.0 18.0 0.2

MC25-229 94.7 145.8 51.1 0.2

Including 102.7 119.7 17.0 0.5

Including 102.7 105.7 3.0 1.3

MC25-231 35.5 66.5 31.0 0.4

Including 41.0 56.0 15.0 0.6

Including 54.0 56.0 2.0 1.9

And Including 65.9 66.5 0.6 2.5

And 123.0 130.5 7.5 0.3

Including 123.0 124.0 1.0 1.1

MC25-236 71.0 71.7 0.7 6.0

And 115.5 124.0 8.5 0.4

Including 115.5 116.5 1.0 1.5

And 166.0 172.0 6.0 0.3

And 217.0 218.0 1.0 1.1

And 239.7 245.0 5.3 0.4

And 263.2 265.5 2.3 0.5

*Intersections are reported as drilled width; true width is 60-90% of drilled width

Table 1 (Continued)

Target From To Length Au

Drill Hole (m) (m) (m) (g/t)

Argus North

MC25-238 148.6 197.5 48.9 1.2

Including 154.5 156.5 2.0 2.9

And Including 175.0 176.0 1.0 4.8

And Including 182.2 184.0 1.8 2.3

And Including 194.4 195.5 1.1 2.8

And 301.5 304.9 3.4 0.7

And 361.0 372.0 11.0 0.3

MC25-248 4.0 32.0 28.0 1.6

Including 4.0 24.1 20.1 2.1

Including 21.0 23.0 2.0 6.5

And 73.0 115.0 42.0 1.8

Including 73.0 75.0 2.0 5.2

And Including 89.0 101.0 12.0 4.0

Including 96.0 100.0 4.0 8.0

And 154.5 155.5 1.0 1.0

MC25-251 2.8 44.8 42.0 1.4

Including 4.0 11.5 7.5 1.9

And Including 37.0 44.8 7.8 3.5

Including 41.0 43.0 2.0 7.1

And 62.0 107.9 45.9 1.4

Including 67.0 70.0 3.0 1.4

And Including 87.0 106.0 19.0 2.6

Including 87.0 91.0 4.0 7.2

Including 89.0 90.0 1.0 11.1

And 121.0 134.5 13.5 0.5

And 256.0 274.5 18.5 0.2

MC25-254 107.0 108.0 1.0 1.7