America’s Newest Copper Producer Delivers First Revenue Milestone

Gunnison Copper Corp. (TSX: GCU) (OTCQB: GCUMF) (FSE: 3XS0) is pleased to announce the first sales of pure copper cathode from its fully operational Johnson Camp Mine in southeast Arizona, with production capacity of up to 25 million lbs. of copper cathode annually.

On September 15, 2025, Gunnison completed its inaugural copper sales, marking the start of revenue generation following successful commissioning. Gunnison sold a total of 225,371 pounds of finished copper cathode at an average realized copper price of US$4.64 per pound, generating gross proceeds of approximately US$1,046,194.

“This milestone represents the first revenue from Johnson Camp and demonstrates the rapid progress Gunnison has made in delivering value to shareholders since achieving first copper production just weeks ago,” stated Craig Hallworth, Senior Vice President and Chief Financial Officer. “Strong copper prices and increasing production levels position us well as we move towards a potential equity valuation re-rating as a copper producer. We are especially proud that every pound sold is 100% Made-in-America copper, directly supporting our nation as we work together to strengthen our supply chains.”

Key Highlights of First Copper Sales:

• Revenue milestone achieved: First sales total 225,371 lbs. of finished copper cathode, generating over US$1.0 million in gross proceeds.
• Strengthened U.S. supply chain: Sales represent the first Made-in-America copper from JCM delivered into domestic markets.
• Nuton^® Technology: First copper production using Nuton’s bio-leaching technology is expected later this year. Nuton , a venture of Rio Tinto, will be deploying this innovative technoogy at scale for the first time at Johnson Camp.
• Continued growth trajectory: JCM has a nameplate capacity of 25 million pounds of finished copper cathode annually.

Johnson Camp Mine commenced production in the last week of August 2025, ahead of schedule, and with an excellent health and safety record. Copper cathode from JCM is fully produced in the United States, contributing directly to American energy independence, advanced manufacturing, technology, and national defense supply chains.

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Figure 1 – First copper sale being shipped from Johnson Camp Mine.

ABOUT GUNNISON COPPER

Gunnison Copper Corp. is a multi-asset pure-play copper developer and producer that controls the Cochise Mining District (the district), containing 12 known deposits within an 8 km 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% (Measured Mineral Resource of 191.3 million tons at 0.37% and Indicated Mineral Resource of 640.2 million tons at 0.29%), and a preliminary economic assessment yielding robust economics including an NPV8% of $1.3Billion, IRR of 20.9%, and payback period of 4.1 years. It is being developed as a conventional operation with open pit mining, heap leach, and SX/EW 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 funded by Nuton LLC, a Rio Tinto Venture, with a production capacity of up to 25 million lbs of finished copper cathode annually. Copper revenues from Johnson Camp accrue to Nuton LLC until such time as Nuton LLC has received payback of all of its funding for Johnson Camp.

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 November 1, 2024 and available on SEDAR+ at www.sedarplus.ca.

Dr. Stephen Twyerould, Fellow of AUSIMM, President and CEO of the Company is a Qualified Person as defined by NI 43-101. Dr. Twyerould has reviewed and is responsible for the technical information contained in this news release.

For more information on Gunnison, please visit our website at www.GunnisonCopper.com

ABOUT NUTON

Nuton is an innovative venture that aims to help grow Rio Tinto’s copper business. At the core of Nuton is a portfolio of proprietary copper leaching technologies and capability. Nuton has the potential to economically unlock copper from hard-to-leach ores, including primary sulfides and, in doing so, increase domestic production of critical minerals to support the energy transition. Nuton technologies can achieve market-leading recovery rates and boost copper production in new, ongoing and historical operations, increasing resource utilization and maximizing value.

With significantly lower energy and water needs than conventional concentrating and smelting, and the ability to produce copper cathode at the mine site, Nuton offers a reliable source of domestically produced copper, with a short mine-to-metal supply chain and the ambition to set industry-leading ESG credentials.

One of the key differentiators of Nuton is the ambition to produce the world’s lightest environmental footprint copper while having at least one Positive Impact at each of its deployment sites, across its five pillars: water, energy, land, materials and society.