Vancouver, British Columbia--(Newsfile Corp. - December 15, 2025) - Transatlantic Mining Corp. (TSXV: TCO) (the "Company") 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."

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 (TSXV: 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 Montana, moving towards 100% ownership by way of a payment royalty. https://www.transatlanticminingcorp.com/

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, 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 forward-looking statements, except as required by law.

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.

To view the source version of this press release, please visit https://www.newsfilecorp.com/release/278020