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ONYX.V ·

Onyx Gold Reports New High-Grade Vein Discovery at Munro-Croesus Project, Timmins, Ontario Hole MC23-132 Intersects 363.0 g/t (10.59 opt) Au over 0.3m Within a Broader Interval of 121.8 g/t (3.55 opt) Au over 0.9m

Drill Results

Onyx Gold Reports New High-Grade Vein

Discovery at Munro-Croesus Project, Timmins,

Ontario

Hole MC23-132 Intersects 363.0 g/t (10.59 opt) Au over 0.3m

Within a Broader Interval of 121.8 g/t (3.55 opt) Au over 0.9m

Vancouver, British Columbia--(Newsfile Corp. - December 6, 2023) -

Onyx Gold Corp. (TSXV: ONYX)

(OTCQX: ONXGF)

("

Onyx

" or the "

Company

") is pleased to announce initial exploration results from

its 2023 Fall drill program in the Timmins gold camp, Ontario. The first assay results have been returned

for drill hole MC23-132, which tested a prospective area 350m (1,148 feet) northwest of the former

Croesus Gold Mine. The Croesus Gold Mine is famous for yielding some of the highest-grade gold

mined in Ontario.

The completed program included ~4,000 meters ("m") of diamond drilling with one drill rig and focused

on targets proximal to the historic high-grade Croesus Gold Mine, and on the new bulk-tonnage-style

Argus Zone discovered in 2022.

Highlight Assay Results for Drill Hole MC23-132 include:

121.8 grams per tonne ("g/t") (3.55 ounces per ton "opt") gold ("Au") over 0.9m

(true

width), including

363.0 g/t (10.59 opt) Au over 0.3m

(true width)

The drill hole intersected a 30-centimeter-wide quartz vein containing

abundant visible gold

that

returned

363 g/t (10.59 opt) Au over 0.3m

, representing the single highest assay in the Company's drill

hole database for the project. The high-grade vein occurs within a broader zone of mineralization

averaging

121.8 g/t (3.55 opt) Au

over 0.9m

and was intersected approximately 60 m vertically below

surface. This new vein discovery represents an entirely new high-grade quartz vein in a geological

setting comparable to the mined-out, bonanza-grade Croesus vein.

"The intersection of multi-ounce gold grades within a completely new vein system parallel to the

renowned Croesus Vein is a direct validation of the team's recent advancements in geological and

structural modeling in the area," said Brock Colterjohn, President & CEO. "The historic Croesus Gold

Mine produced some of the highest-grade gold ever mined in Ontario, with an average head grade of

95.3 g/t (2.78 opt) gold. This new vein underscores the opportunity for additional discoveries within an

established high-grade gold environment. It is an excellent start to Onyx Gold's inaugural drill program in

Ontario."

"The Timmins camp is one of the most prolific gold-producing regions in the world with multiple

operating mines and excess milling capacity. Onyx Gold has established one of the largest land

positions in the camp not owned by a producer. Much of this land package is in prime high-potential

geology with little or no work completed for decades. Our land tenure represents particularly attractive

opportunities for discoveries such as this. This new vein remains open in all directions, and we look

forward to further expanding this high-grade discovery in a winter drill campaign. We are also looking

forward to results from the rest of our fall program which will be reported in due course."

Discussion of Results

A total of five (5) holes (MC23-130 to MC23-134) totaling 872m were completed by the Company in late

October/early November to follow-up north and south of drillhole MC22-92 drilled by the previous

operator, HighGold Mining Inc., which intersected a narrow quartz vein that returned

14.0 g/t Au over 0.6

meters

in a broader interval grading

3.4 g/t Au over 2.6m

(

See HighGold Mining Inc. press release

from March 30, 2022

).

The area was targeted for its similar geological setting to the Croesus Gold Mine

- specifically, the occurrence of a parallel vein to the Croesus Vein within a particular basalt flow unit that

is locally brecciated and enriched in sulfides (the "Croesus Flow").

The Croesus Flow is interpreted to

play an important role in the deposition of exceptionally high concentrations of gold within the Croesus

Vein.

Results have been returned from hole MC23-132, a 25-meter step-out south of MC23-92, which

intersected what is believed to be a new vein in a parallel orientation to the Croesus Vein within the

upper portion of the Croesus Flow.

The quartz vein was intersected from 83.0-83.3 meters downhole

within sulfidic pillowed Croesus Flow and returned the highest-grade interval on the property to date of

363.0 g/t Au over 0.3m

(true width) within a broader structural zone averaging

121.8 g/t Au over 0.9m

(true width). The quartz vein is characterized by massive, white-grey quartz with abundant fine-grained

aggregates of visible gold throughout and in and along the margins of pyrite grains.

The quartz contains

coarse, disseminated, and fracture-filling pyrite and trace, fine-grained sphalerite, and arsenopyrite as

shown in

Plate 1.

The

363.0 g/t Au

assay was obtained by gold gravimetric analysis (Au-GRA22) at the

ALS Canada lab in North Vancouver.

A gold screen analysis (Au-SCR21) was also performed and

returned a total gold value of

342.0 g/t Au

.

Between 1915 and 1936, the Croesus Mine, produced 14,854 ounces of gold mined from 5,333 tons

with an average grade of 2.78 opt Au (

95.3 g/t Au

) as reported by the Ontario Department of Mines in

1951.

Note - this production number did not include the ore that was mined and shipped in packing

crates directly to the Royal Canadian Mint.

Five (5) gold samples purchased by the Ontario Bureau of

Mines for exhibition purposes and now in possession of the Royal Ontario Museum in Toronto, Ontario

weigh 85 pounds collectively and contain 480.7 ounces of gold or

11,310 oz gold per ton (387,727

g/tonne

). The Croesus Vein and the new vein are parallel northeast-striking, east-southeast-dipping

shear veins that contain abundant visible gold where they intersect the permissive host lithology

(Croesus Flow). This highlights the opportunity to discover additional parallel high-grade veins within the

Croesus Flow.

Drill hole locations for the holes reported herein are shown in

Figures 2 and 3.

Assay results for the

other four holes to test the target area are currently pending.

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 1

).

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 from 2020-2023 has unified the patchwork of patented and

unpatented mining claims surrounding the Croesus Gold Mine into one coherent package (

Figure 1

)

and enhanced the exploration potential of the Project.

The Project covers 70 km

2

(27 mi

2

) 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. that contains an Indicated Resource of 3.38

Moz at 0.93 g/t Au and an Inferred Resource of 157 koz at 0.85 g/t Au, and the Tower Gold Project being

developed by Moneta Gold Inc. that contains an open pit Indicated Resource of 4.46 Moz at 0.92 g/t Au

and an Inferred Resource of 8.29 Moz at 1.09 g/t Au

1

.

Figure 1 - Location of Munro-Croesus Gold Project, Ontario

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/9800/189987_5808417534ddb99d_002full.jpg

Figure 2 - Plan Map of Croesus Mine Area Drill Holes

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/9800/189987_5808417534ddb99d_003full.jpg

Figure 3 - Cross-section of New Vein Discovery in Drill Hole MC23-132

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/9800/189987_5808417534ddb99d_004full.jpg

Plate 1 - Photo of Abundant Visible Gold in Drill Hole MC23-132

To view an enhanced version of this graphic, please visit:

https://images.newsfilecorp.com/files/9800/189987_5808417534ddb99d_005full.jpg

Q4-2023 Ontario Drill Program

The Company successfully completed its planned fall drill program on December 2

nd

with 4,078 meters

drilled in 19 holes.

Approximately half of the drilling budget was focused on expansion drilling at the

Argus Zone located on the western side of the Property, with the remaining half of the drilling budget

focused on follow-up holes at targets proximal to the historic high-grade Croesus Gold Mine.

Assay

results from the fall program are currently pending and will be released in due course.

About the Timmins Area Gold Properties

Onyx owns 100% of each of its three Timmins properties.

The Munro-Croesus Gold Project is located

approximately 75 kilometers (47 miles) east of Timmins, proximal to the Porcupine-Destor and

Pipestone Faults, and approximately two kilometers (1.2 miles) northwest and along trend of Mayfair

Gold Corp.'s multi-million ounce Fenn-Gib gold deposit. Mining occurred intermittently at Munro-Croesus

between 1915 and 1936.

The Golden Mile 140 square kilometer (54 square miles) property is located

nine kilometers (5.6 miles) northeast of Newmont's multi-million-ounce Hoyle Pond deposit in Timmins.

The Timmins South (Golden Perimeter) 187 square kilometers (72 square miles) property is located to

the south and southeast of Timmins and surrounds the Shaw dome structure.

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 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 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 shareholder value through the discovery

process, careful allocation of capital, and environmentally/socially responsible mineral exploration.

Qualified Person and Quality Assurance

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.

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, VP of Corporate Communications

Phone:

1-604-629-1165

or North American toll-free

1-855-629-1165

Email:

[email protected]

or

[email protected]

.

Website:

www.onyxgold.com

Twitter :

@OnyxGoldCorp

1. Fenn-Gib Gold Project and Tower Gold Project mineral resources compiled from public sources and are provided for general information purposes.

Readers are cautioned that the Company has no interest in or right to acquire any interest in adjacent properties and they are not indicative of

mineral deposits on the Company's properties or any potential exploration thereof.

Additional Notes:

Starting azimuth, dip and final length (Azimuth/-Dip/Length) for the drillholes reported today are noted as

follows: MC23-132 (300/45/126).

Samples of drill core were cut by a diamond blade rock saw, with half of the cut core placed in individual

sealed polyurethane bags and half placed back in the original core box for permanent storage. Sample

lengths typically vary from a minimum 0.2-meter interval to a maximum 1.5-meter interval, with an

average 0.5 to 1.0-meter sample length.

Drill core samples were delivered by truck in sealed woven

plastic bags to ALS Geochemistry laboratory facility in Timmins, Ontario for sample preparation with

final analysis at ALS Geochemistry Analytical Lab facility in North Vancouver, BC.

ALS Geochemistry

operate meeting all requirements of International Standards ISO/IEC 17025:2017 and ISO 9001:2015.

Gold is determined by fire-assay fusion of a 50-gram sub-sample with atomic absorption spectroscopy

(AAS).

Samples that return values >10 ppm gold from fire assay and AAS are determined by using fire

assay and a gravimetric finish. Various metals including silver, gold, copper, lead and zinc are analyzed

by inductively-coupled plasma (ICP) atomic emission spectroscopy, following multi-acid digestion.

The

elements copper, lead and zinc are determined by ore grade assay for samples that return values

>10,000 ppm by ICP analysis.

Silver is determined by ore-grade assay for samples that return >100

ppm. All ALS Geochemistry sites operate under a single Global Geochemistry Quality Manual that

complies with ISO/IEC 17025:2017. ALS Geochemistry follows the quality management and operational

guidelines set out in the international standards ISO/IEC 17025 - "General Requirement for the

Competence of Testing and Calibration Laboratories" and ISO 9001 - "Quality Management Systems".

The Company maintains a robust QA/QC program that includes the collection and analysis of duplicate

samples and the insertion of blanks and standards (certified reference material).

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.

Forward looking information: This news release includes certain "forward-looking information" within

the meaning of Canadian securities legislation and "forward-looking statements" within the meaning

of the United States Private Securities Litigation Reform Act of 1995 (collectively "forward looking

statements").

Forward-looking statements include predictions, projections, and forecasts and are often, but not

always, identified by the use of words such as "seek", "anticipate", "believe", "plan", "estimate",

"forecast", "expect", "potential", "project", "target", "schedule", "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 Company's planned

exploration programs and drill programs and potential significance of results including the new high-

grade vein structure at the Munro Croesus property described above, are forward-looking statements

that involve various risks and uncertainties. There can be no assurance that such statements will

prove to be accurate and actual results and future events could differ materially from those anticipated

in such statements. Forward-looking statements are based on a number of material factors and

assumptions. Important factors that could cause actual results to differ materially from Company's

expectations include actual exploration results, changes in project parameters as plans continue to

be refined, results of future resource estimates, future metal prices, availability of capital, and

financing on acceptable terms, general economic, market or business conditions, uninsured risks,

regulatory changes, defects in title, availability of personnel, materials, and equipment on a timely

basis, accidents or equipment breakdowns, delays in receiving government approvals, unanticipated

environmental impacts on operations and costs to remedy same, and other exploration or other risks

detailed herein and from time to time in the filings made by the Company with securities regulators.

Although the Company has attempted to identify important factors that could cause actual actions,

events, or results to differ from those described in forward-looking statements, there may be other

factors that cause such actions, events, or results to differ materially from those anticipated. There can

be no assurance that forward-looking statements will prove to be accurate, and accordingly readers

are cautioned not to place undue reliance on forward-looking statements.

To view the source version of this press release, please visit

https://www.newsfilecorp.com/release/189987