Dr. Stephen Twyerould reports

GUNNISON COPPER ANNOUNCES THAT RIO TINTO'S NUTON TECHNOLOGY PRODUCES FIRST COPPER

Rio Tinto has successfully produced the first copper from Gunnison Copper Corp.'s Johnson Camp mine in Arizona using its Nuton technology, marking a pivotal step forward in the development of this innovative copper processing technology.

After more than 30 years of research and development, the first copper cathode using Rio Tinto's proprietary bioleaching technology, which relies on microorganisms grown on site, was produced at Gunnison Copper's Johnson camp mine last month. The deployment involves the design and delivery of a technology package for a heap-leach pad targeting production of approximately 30,0001 tonnes of refined copper over a four-year demonstration period. Rio Tinto is engaging with several potential customers in the United States to support the domestic copper supply chain.

Rio Tinto Copper chief executive Katie Jackson said: "This is a breakthrough achievement for our Nuton technology, which is proving that cleaner, faster and more efficient copper production is possible at an industrial scale. In an industry where projects typically take about 18 years to move from concept to production, Nuton has now proven its ability to do this in just 18 months.

"Nuton has designed a modular system deployed as a technology package integrating biology, chemistry, engineering and digital tools, allowing it to be rapidly scaled and tailored to different orebodies, unlocking resources that have historically been considered uneconomic or challenging. We are actively partnering on projects in North and South America to assess the potential for future deployment at additional sites in the coming years."

Nuton relies on naturally occurring micro-organisms to extract copper from primary sulphide materials, which are traditionally difficult to process. These microbes, grown at large scale in Nuton's proprietary bioreactors, accelerate the oxidation of minerals in the crushed material heap, generating heat and enabling copper to dissolve into a leach solution, which is then processed into 99.99-per-cent-pure copper cathode.

Significantly, processing copper material with Nuton eliminates the need for concentration, smelting and refining, shortening supply chains and delivering copper cathode at the mine gate. It achieves recovery rates of up to 85 per cent from primary sulphides, the most abundant copper-bearing materials in the world.

Nuton can also extend mine life and maximize resource use by extracting value from mineralized materials that would otherwise be classified as waste, increasing yield and revenue at both new and existing mines. Its environmental performance is expected to exceed conventional copper processing technologies, with up to 80 per cent less water usage and up to 60 per cent lower carbon emissions than the traditional concentrator route.

At Johnson Camp, Nuton aims to produce copper with the lowest carbon footprint in the United States. Through the purchase of 134,000 Green-e Energy-certified renewable energy certificates, Nuton ensures 100 per cent of the site's electricity is matched by renewable sources. The copper produced is anticipated to have a mine-to-metal carbon footprint of 0.82 kilogram CO2e (carbon dioxide equivalent) per kilogram copper, the lowest in the United States and substantially lower than the projected 2026 global average of 3.4 kilograms CO2e per kilogram among operating copper mines. Additionally, water intensity is anticipated to be 71 litres per kilogram copper, compared with the global average industry estimate of approximately 130 litres per kilogram of copper production.

Gunnison Copper chief executive officer and president Dr. Stephen Twyerould said: "The first production of Nuton copper at Johnson Camp is the culmination of exceptional teamwork between Gunnison Copper and Rio Tinto's Nuton team. Achieving this level of performance in such a short time frame shows what is possible when innovation, operational excellence and a shared vision come together. With Nuton copper now entering the U.S. supply chain, this milestone underscores the critical role we can play in strengthening domestic access to cleaner, low-carbon copper."

While this milestone confirms Nuton's engineering and operational viability, the next phase will focus on validating long-term technical performance. This includes multiyear testing, independent third party verification and internal review by Rio Tinto to ensure consistent recovery rates and environmental performance.

About Gunnison Copper Corp.

Gunnison Copper is a multiasset pure play copper developer and producer that controls the Cochise mining district, containing 12 known deposits within an eight-kilometre economic radius, in the Southern Arizona copper belt.

Its flagship asset, the Gunnison copper project, has a measured and indicated mineral resource containing over 831.6 million tons with a total copper grade of 0.31 per cent (measured mineral resource of 191.3 million tons at 0.37 per cent and indicated mineral resource of 640.2 million tons at 0.29 per cent) and a preliminary economic assessment (PEA) yielding robust economics, including a net present value (discounted at 8 per cent) of $1.3-billion, an internal rate of return of 20.9 per cent and a payback period of 4.1 years. It is being developed as a conventional operation with open-pit mining, heap leach and an SX/EW (solvent extraction/electrowinning) refinery to produce finished copper cathode on site with direct rail link.

The PEA is preliminary in nature and includes inferred mineral resources that are considered too speculative geologically to have the economic considerations applied to them that would enable them to be categorized as mineral reserves. There is no certainty that the conclusions reached in the PEA will be realized. Mineral resources that are not mineral reserves do not have demonstrated economic viability.

In addition, Gunnison's Johnson Camp asset, which is now in production, is fully financed by Nuton LLC, a Rio Tinto venture, with a production capacity of up to 25 million pounds of finished copper cathode annually.

Other significant deposits controlled by Gunnison in the district, with potential to be economic satellite feeder deposits for Gunnison project infrastructure, include Strong and Harris, South Star, and eight other deposits.

For additional information on the Gunnison project, including the PEA and mineral resource estimate, please refer to the company's technical report entitled "Gunnison Project NI 43-101 Technical Report Preliminary Economic Assessment," dated effective Nov. 1, 2024, and available on SEDAR+.

Dr. Twyerould, a fellow of AusIMM and president and chief executive officer of the company, is a qualified person as defined by National Instrument 43-101. Dr. Twyerould has reviewed and is responsible for the technical information contained in this news release.

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