Onyx Gold Launches 2025 Exploration Program at King Tut in Yukon’s Eastern Tombstone Belt Program Focuses on Advancing and Expanding the Ra Intrusion Vein Field Discovery to Refine Future Drill Targets
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August 12th, 2025 NR# 031-2025
NEWS RELEASE
Onyx Gold Launches 2025 Exploration Program at King Tut in
Yukon’s Eastern Tombstone Belt
Program Focuses on Advancing and Expanding the Ra Intrusion Vein Field Discovery to
Refine Future Drill Targets
Vancouver, BC – August 12th, 2025 – Onyx Gold Corp. (“Onyx” or the " Company") (TSX-V:
ONYX, OTCQX: ONXGF) is pleased to announce that field crews have mobilized to its King Tut
Property (“King Tut” or the “ Property”) in Yukon’s eastern Tombstone Gold Belt to launch the
Company’s 2025 summer exploration program. Located 40 kilometres north of the North Canol
Road, King Tut lies within one of Yukon’s most prospective and rapidly emerging metals districts,
an area attracting increased attention following several recent discoveries by Snowline Gold and
Fireweed Metals (Figure 1).
The 2025 program will focus on the Ra target (“Ra”), advancing Onyx’s systematic evaluation of
this underexplored, gold-bearing intrusion through detailed mapping and extensive channel and
grab sampling - work designed to pinpoint the most prospective zones for future drilling.
2025 Exploration Program & Ra Intrusion Highlights
• The Ra intrusion, last explored in 1996, hosts widespread, multigenerational, gold-bearing
sheeted quartz veins within a 3 x 2 km exposed granitic body.
• In May 2024, Onyx entered into an option agreement to acquire the Ra Property (formerly
WEAS), consolidating King Tut and providing full control of two mineralized intrusions —
Golden Mask and Ra — located 9 km apart (see news release dated May 9, 2024).
• An initial reconnaissance program by Onyx in July 2024 confirmed an extensive sheeted
vein field at Ra and returned a high -grade surface rock sample grading 25.1 g/t Au
(Figures 2 and 3).
• On August 5 th, 2025, the Company received approval of its Class 1 Notification
(Q2025_0140) from the Mayo Mining District, Yukon Government, authorizing surface
exploration and up to 5,000 metres of diamond drilling from 10 sites across King Tut.
• On August 9 th, 2025, Onyx commenced a fly -camp-based, 21-day field program (the
“Program”) on the Ra target to systematically evaluate its extensive sheeted vein field
through detailed alteration and vein mapping, as well as extensive rock and channel
sampling.
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“We’re excited to return to the Yukon to launch our 2025 field program at King Tut, targeting the
prospective Ra intrusion in the heart of the emerging Tombstone Gold Belt,” said Brock Colterjohn,
President & CEO of Onyx Gold. “Historic work at Ra identified widespread gold -bearing quartz
veins, and our 2024 reconnaissance program returned a standout grab sample of 25 g/t Au. This
season’s expanded program is aimed at building on that success, refining drill targets, and
positioning Onyx to deliver meaningf ul discovery results in a district already making headlines
with major finds from neighbouring explorers.
These are exciting times for Onyx and our shareholders, as we explore in two of Canada’s top
gold jurisdictions - Yukon and Ontario - simultaneously for the first time in our history. We look
forward to reporting results from both in the weeks and months ahead.”
Details of the Ra Target at King Tut and the 2025 Summer Field Program
The King Tut Property is in the heart of an emerging reduced intrusive-related gold district in the
Selwyn Basin , Yukon . Previous fieldwork at King Tut identified two large-scale gold -in-soil
anomalies, Golden Mask and Main Tut, in a comparable geological setting to Snowline Gold’s
Valley deposit, one of the most significant recent new gold discoveries globally, located only 50
km away.
In 2024, field work by the Company focused on follow-up contour and grid soil sampling and rock
sampling at the Golden Mask anomaly, and detailed geological and vein mapping and rock
sampling at the new Ra target . Each of these targets is associated with two separate intrusion-
related gold systems. The work was conducted by a four-person field crew from Archer, Cathro &
Associates (1981) Limited, based in Whitehorse, Yukon, over a 20 -day period in July 2024 and
returned encouraging results from the Ra Target that warrant follow-up in 2025.
Ra Target
The Ra target is located near the center of the Property, and within the hornfelsed aureole on the
southwest margin of a large quartz monzonite/granite stock (Figure 2 ). The Ra target hosts
multigenerational gold-bearing sheeted quartz veins within an exposed, 3 x 2 km granitic intrusion.
Prior drilling intersected 1.0 g/t Au over 21 meters (true width unknown) associated with the
sheeted quartz veins, along with surface grab samples of up to 20.1 g/t Au.
During the 2024 program, the Company focused its work on the Ra sheeted vein fields, collecting
135 rock channel samples and 13 rock grab samples, and conducting detailed mapping of vein
density and intrusive margins (Figure 2 and Figure 3). The area features abundant north-south-
oriented sheeted quartz veins and locally sheeted quartz -arsenopyrite (+/- bismuthinite) veins.
Sampling returned values up to 25.1 g/t Au from sub -cropping vein material, corroborating
historical findings.
Vein density mapping has defined a promising vein field approximately 1,700 x 1,000 meters in
size ( Figure 3). Gold grades appear to be related to vein density and increase towards the
western margin of the intrusion.
In 2023, a 1,692-line kilometer property -wide drone -based magnetic geophysical survey was
flown over the King Tut Property. New processing of this data in 2024 by the Company’s
independent geophysical consultant generated 3D inversion models for both magnetic
susceptibility and magnetic vector inversion. This inversion effectively delineate d the magnetic
structures of King Tut and Golden Mask, providing valuable insights into subsurface geology.
The Company has planned a fly-camp-based 2025 field program on the Ra target to continue to
evaluate the sheeted vein field through detailed alteration and vein mapping, along with extensive
rock and channel sampling. The Program will be carried out by a field crew of up to 8 people from
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Archer, Cathro & Associates (1981) Limited, based in Whitehorse, Yukon, over a 21-day period in
August and September 2025.
Update on Activities on the Munro-Croesus Gold Property, Ontario
The Company has completed 40 drill holes totalling ~12,000 meters to date as part of its fully
funded Phase 1 drill program at the Argus North Zone at its Munro -Croesus property (“Munro-
Croesus”) in Ontario. The drill program continues to focus on step-out drilling along strike on 50-
m to 100-m spaced cross-sections designed to extend the limits of the known Argus North gold
mineralization. Results have been released for only 9 holes in this program to date.
The Company’s Board of Directors recently approved a 150% increase in the size of the drill
program from 10,000 to 25,000 meters based on the strong results to date at Argus North (See
news release dated July 23, 2025). Additional drilling will continue to systematically step out east
and west along the key prospective variolitic basalt flows immediately north of the Pipestone Fault
and to target other high-quality targets over the large 109 km2 Project area.
In addition, the Company has launched bedrock excavation program at Munro-Croesus to expose
the surface projection of Argus North gold mineralization intersected in the top of drill hole MC25-
180 using mechanical stripping to complete detailed mapping and channel sampling of the
outcrop. The Company also plans to complete ground -based induced polarization geophysical
surveying to infill the 200 m spaced gridlines completed in winter of 2021 -2022 over the Argus
Main and Argus North zones.
The TSX Venture Exchange (the “TSXV”) Provides Acceptance of the Previously
Announced Munro Purchase Agreement
The Company also reports that, further to its news release dated June 24, 2025, the TSXV has
provided their approval of the mineral property purchase and sale agreement (the “ Munro
Agreement”) to acquire a 100% interest in the Munro property (the “ Munro Property”). The
Company has the right to acquire the Munro Property by making two staged cash payments over
12 months for a total aggregate consideration of $300,000 and subject to the completion of
satisfactory due diligence, including receipt and review of environmental study results. Up to
$50,000 of such payment is payable, at the Company’s election, in common shares of the
Company. In addition, the Company will also make a one-time bonus cash payment of $500,000
to the vendor or to any nominee of its choice if a mineral resource exceeding 500,000 ounces of
gold in the Measured and Indicated categories is defined on the Munro Property, as reported in a
National Instrument 43-101 – Standards of Disclosure for Mineral Projects technical report, within
a period of 5 years from the closing date.
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Figure 1 - Regional Property Map
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Figure 2 – Property Map – Golden Mask, Ra, and Main Tut Targets
Note - Highlighted historical samples noted herein have not been verified by the Company, but
they provide evidence for the general gold endowment of the claims. Grab samples are selective
in nature and don’t necessarily represent bulk tonnage grades
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Figure 3 – Property Map - Ra Target
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Figure 4 – 2025 Fly Camp Established on August 9th
Figure 5 – Channel Sampling Underway (Left) & High-density Sheeted Veins
(Right)
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About Onyx Gold
Onyx Gold is an exploration company focused on well-established Canadian mining jurisdictions,
with assets in Timmins, Ontario, and Yukon Territory. The Company’s extensive portfolio of quality
gold projects in the greater Timmins gold camp includes the Mu nro-Croesus Gold property,
renowned for its high -grade mineralization, plus two additional earlier -stage large exploration
properties, Golden Mile and Timmins South. The Golden Mile 140 km 2 property is located 9 km
northeast of Discovery Silver’s multi-million-ounce Hoyle Pond deposit in Timmins. The Timmins
South 187 km2 property is located to the south and southeast of Timmins and surrounds the Shaw
dome structure.
Onyx Gold also controls four properties in the Selwyn Basin area of Yukon Territory, 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 sharehold er value through the
discovery process, careful allocation of capital, and environmentally/socially responsible mineral
exploration.
On Behalf of Onyx Gold Corp.
“Brock Colterjohn”
President & CEO
For further information, please visit the Onyx Gold Corp. website at www.onyxgold.com or contact:
Brock Colterjohn, President & CEO
or
Nicole Hoeller, NIKLI Communications – [email protected]
Phone: 1-604-283-3341
Email: [email protected]
Website: www.onyxgold.com
LinkedIn: https://www.linkedin.com/company/onyx-gold-corp
Twitter: https://twitter.com/OnyxGoldCorp
Additional Notes:
Ian Cunningham-Dunlop, P.Eng., Executive Vice President for Onyx Gold Corp. and a qualified
person ("QP") as defined by Canadian National Instrument 43 -101, has reviewed and approved
the technical information contained in this release.
Neither TSX Venture Exchange nor its Regulation Services Provider (as that term is defined in
the policies of the TSX Venture Exchange) accepts responsibility for the adequacy or accuracy of
this release.
Cautionary and Forward-Looking Statements
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“target”, “s chedule”, “budget” and “intend” and statements that an event or result “may”, “will”, “should”, “could” or
“might” occur or be achieved and other similar expressions and includes the negatives thereof. All statements other
than statements of historical fact included in this release, including, without limitation, statements regarding the potential