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Outer Rim Exploration Launches Maiden Muon Imaging Survey for Copper Mineralisation with Transatlantic Mining

Exploration Programs

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

Outer Rim Exploration Launches Maiden Muon Imaging Survey for Copper

Mineralisation with Transatlantic Mining

Vancouver, B.C. December 15, 2025 - Transatlantic Mining Corp. (the “Company”)

(TCO:TSX.V) is pleased to announce the company has engaged a maiden technical trial with

Outer Rim Exploration (“ORE”) utilising a new Muon enhanced technique to identify voids

and new mineralisation association at its Monitor Copper Gold project in Idaho USA.

The campaign marks the first North American deployment of ORE’s portable muon

hodoscope for the mining industry. The survey will evaluate the continuity and potential

size of a chalcopyrite-rich copper ore zone and map unmapped historical mine workings

within the area.

The new muon-based tomography system aims to accelerate subsurface mapping and

reduce drilling costs in mineral exploration.

Business and Technical Impact

By imaging both mineralized and void zones, ORE’s data will provide Transatlantic with

valuable insights into orebody geometry and historical mine dimensions. This improved

understanding will support drill planning, future mine planning, cost optimization, and risk

reduction associated with drilling and mine excavation.

“Our goal is to replace guesswork with captured data,” said Jeremy Anderson, CEO and Co-

Founder of Outer Rim Exploration.

Bernie Sostak, CEO of Transatlantic Mining , said, “With a portable detector, we can image

historical underground cavities, and provide clarity that usually takes months of drilling to

achieve. We are also excited to partner with Outer Rim to evaluate the potential extensions

of the known and unknown copper-bearing chalcopyrite mineralization. This collaboration

represents a new frontier in mineral imaging, bringing particle physics to the service of

practical exploration.”

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

Survey Objectives

ORE’s muon hodoscope operates as a fully stand-alone, battery-powered, passive, and

environmentally friendly imaging platform that requires no active radiation source or

drilling. Compact and ruggedized, the system fits within narrow adits and underground

passages or can be deployed on the surface, enabling continuous autonomous scanning

over weeks of operation—even in remote or constrained environments.

The survey will determine whether the chalcopyrite-bearing copper mineralization,

previously observed at widths ranging from 0.3 m width, and looking to extend laterally

along strike and/or vertically. ORE’s detectors will also image subsurface voids to improve

geotechnical understanding and guide future exploration drilling.

Next Steps

Following the campaign, ORE will process the muon data through its proprietary AI-driven

density-mapping pipeline to generate 2D and 3D visualizations of subsurface density

variations. The findings will inform Transatlantic’s exploration strategy and guide future

deployments across additional sites in North America.

About Outer Rim Exploration (ORE)

Outer Rim Exploration Inc. is a deep-tech company pioneering portable muon tomography

systems for subsurface imaging in mining and infrastructure. ORE’s mission is to

revolutionize how humanity explores beneath the surface of the Earth.

https://www.ore.space/

About Transatlantic Mining Corp.

Transatlantic Mining (TSX -V: TCO) is an emerging precious and base metal explorer. The

Company has a focus on converting projects into mines within stable mining jurisdictions.

The Company currently holds property interests including an 80% Joint Venture position on

the Monitor Copper -Gold project in Montana -Idaho (USA) and 100% of the Golden Jubilee

Gold Project with its associated mining rights. The Company also has an extended lease, right

to mine, and purchase arrangement for the Miller Gold Mine in Mon tana, moving towards

100% ownership by way of a payment royalty.

Cautionary Statement Regarding Forward-Looking Statements

This news release contains "forward -looking statements" within the meaning of Canadian

securities legislation. These forward -looking statements include, but are not limited to,

Transatlantic Mining Corp. | Suite 400 | 837 West Hastings Street | Vancouver | Canada

V6C 3N6 T 604-630 7296 | F 604-357 1139| www.transatlanticminingcorp.com

statements regarding the Company's future exploration plans, geophysical programs, and

the potential for mineralization. Forward -looking statements are subject to known and

unknown risks, uncertainties, and other factors that may cause the actual results, level of

activity, performance, or achievements of the Company to be materially different from those

expressed or implied by such forward-looking statements. These factors include, but are not

limited to, risks associated with the exploration and development of mineral properties, the

Company's ability to obtain necessary permits, and the availability of financing. Readers are

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

undertakes no obligation to update or revise any fo rward-looking statements, except as

required by law.

For further information, please contact: Bernie Sostak:

[email protected] , +61 (0) 439 904 044,

Neither the 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.