Phoenix, Arizona — February 26, 2026 — Leads & Copy — Gunnison Copper Corp. announced the results of an updated NI 43-101 Preliminary Economic Assessment (PEA) on its 100%-owned Gunnison Copper Project in the Cochise Mining District, Arizona.
The PEA, which is effective as of February 22, 2026, supersedes the previous PEA released in December 2024. All dollar amounts are in US dollars, and “tons” refer to U.S. short tons.
According to the release, the Gunnison Copper Project is poised to become a significant supplier to the American copper market. At a consensus copper price of $4.60 per pound, the project delivers an after-tax NPV8 of approximately US$2.0 billion, a 23% IRR, and a 3.9 year payback.
The PEA outlines a conventional open pit, heap leach, SX/EW operation producing 99.999% pure copper cathode. This cathode is intended to supply United States energy, data center, manufacturing, and defense supply chains.
The mine plan consists primarily of oxide copper mineralized material with a life of mine material placed on the leach pad of 541 million tons at 0.43% total copper grade, including 25 million tons at 0.85% total copper grade from the Strong & Harris satellite deposit.
The operation will utilize primary crushing on all material and secondary crushing on some material to improve copper recoveries.
Average annual copper cathode production is projected at 174 million pounds (87 thousand tons) for the first 15 years, potentially supplying over 11% of the current United States domestic refined copper metal production from mineralized material. Total copper produced is estimated at 3.2 billion lbs over a 21-year mine life.
The project boasts cash costs of $1.69, sustaining cash costs of $2.00, and all-in sustaining cash costs of $2.06 per pound of copper produced.
High purity limestone overburden, previously treated as waste, is now used to produce a cement co-product, adding $130M NPV8.
The project is expected to have a significant economic impact, creating over 53,000 jobs, $544 million in state and local county taxes, $1.37 billion in federal taxes, and $14.6 billion in total economic output.
Dr. Stephen Twyerould, CEO, stated that the updated PEA underscores the scale and compelling economics of the Gunnison Copper Project, positioning it as a significant future supplier to the American copper market and a key contributor to the domestic supply shortfall. According to Twyerould, 83% of the $692 million increase in NPV8 versus the 2024 preliminary economic assessment study is driven by operational enhancements within the company’s control, including the addition of the high-grade Strong & Harris satellite deposit, material sorting, cement and limestone co-products, and optimization initiatives.
Key changes versus the 2024 PEA include price deck changes beyond the control of management, such as the change in long-term copper price and operating and capital cost escalation from 2024 to 2026, as well as improvements such as mining the high-grade Strong & Harris satellite deposit.
The 2026 PEA NPV8 is $1,952M, an increase of $692M (+55%) from the 2024 PEA NPV8 of $1,260M. The increase is comprised of Price Deck changes of $117M, 17% of the increase, and Non-Price Deck changes of $576M, the remaining 83% of the increase.
The main driver of price deck changes is the increase in long-term consensus copper price from $4.10/lb in the 2024 study to $4.60/lb in the 2026 study.
The Strong & Harris satellite deposit, located only 1.9 miles from the processing plant, adds over 25 Mtons of high-grade material to the leach pad at 0.85% total copper grade to the processing plan over three years (Y11-Y13).
The mineralized Material Sorting equipment uses optical sensors to detect non-mineralized material amongst the crushed material prior to stacking on the leach pad and diverts it to waste.
Samples were collected in 2025 of the alluvium/conglomerate overburden at Gunnison as part of the HVA program. Their strength and geotechnical characters were analyzed and interpreted resulting in steeper pit walls than the previous study in 2024.
Due to reductions in total acid consumption in the 2026 PEA versus the 2024 PEA, the acid plant capacity was reduced by 10%, from 3,000 to 2,700 tons per day of acid production, along with other beneficial design modifications resulted in savings of $73M in initial capex.
Autonomous Haulage Systems (AHS) have become an accepted mining tool for modern mines. The effect of lowering operating costs is greater than the additional capital required for AHS.
In 2025, drilling and lab testing confirmed the limestone overburden on top of the Gunnison Pit to be a very high purity limestone suitable for producing several saleable products. The rail facility included in the capex has a dedicated outbound capacity of 3M tons per year. Given 1M tons of cement will be sold per year, 2M tons of unrefined high grade limestone will also be sold to third parties at a price of $4.80/ton.
The One Big Beautiful Bill Act of 2025 permanently extended the Bonus Depreciation tax rule that permits 100% deduction of tangible property with a recovery period of 20 years or less, and other qualified improvement property, in the year of expenditure.
The initial mining fleet is now assumed to be capital leased with interest only payments during the construction period that increases the NPV, partially offset by a 125 bps higher lease rate premium included in the lease for this feature.
The PEA base case generates an after-tax Net Present Value of approximately $2.0 billion (at a discount rate of 8%) and an Internal Rate of Return (IRR) of 22.7%.
The Gunnison deposit mineral resources are classified in order of increasing geological confidence into Inferred, Indicated, and Measured categories in accordance with the “CIM Definition Standards – For Mineral Resources and Mineral Reserves” and therefore NI 43-101.
The Strong and Harris mineral resources were modeled to reflect the detailed geologic and structural controls on mineralization. Copper, zinc, and silver mineral domains guided by these geological controls, were interpreted on 200-foot spacing along the approximate direction of dip (045° azimuth).
Certain risks and opportunities are associated with the Project, including environmental permitting, title issues, taxation, public/political opposition, or legal impediments to operating this type of mining/processing operation at this location.
Based on the results of this PEA, it is recommended that GCC consider proceeding with a PFS of the open pit project which is expected to take approximately 18 months.
The Project is in Cochise County, Arizona, approximately 65 miles east of Tucson and is held or controlled 100% by GCC through its wholly owned subsidiary Excelsior Mining Arizona, Inc. (GCAZ) and Excelsior Mining Holdings Inc. (GCH).
GCC has a well-developed community engagement plan that has been implemented through numerous public meetings and outreach programs.
Greenstone Royalty: Greenstone Excelsior Holdings L.P. holds a 3.0% gross revenue royalty over the Gunnison Project.
The Gunnison Project is also subject to a Metal Stream Agreement with Triple Flag Mining Finance Bermuda Ltd. that is applicable to all oxide minerals production from the parts of the Project located in the “Stream Area”.
Callinan Royalties Corporation (now a wholly owned subsidiary of Altius Minerals Corporation) holds a gross revenue royalty over the Gunnison Project.
The Gunnison Project was previously designed as a copper in-situ recovery (ISR) mine using solvent extraction-electrowinning (SX-EW) to produce copper cathode.
The Report will be filed on SEDAR+ and on GCC’s website within 45 days of the date of this news release. The Report will consist of a summary of the PEA.
Gunnison Copper Corp. is a multi-asset pure-play copper developer and producer that controls the Cochise Mining District in the Southern Arizona Copper Belt.
For more information on Gunnison, please visit our website at www.GunnisonCopper.com.
Non-IFRS Financial Measures: This press release contains certain non-IFRS financial measures, including Capex, sustaining capital/capex, sustaining costs, EBITDA, C1 cash costs, free cash flow, and AISC.
Cautionary Note Regarding Forward-Looking Statements: Certain statements contained in this release constitute forward-looking information within the meaning of applicable Canadian securities laws.
Source: Gunnison Copper Corp.
