Drilling intersects 311 feet grading 1.39% copper and 2.29% zinc; flotation testing evaluates potential sulfide processing options, including by-product metal recovery

Gunnison Copper Corp. (NYSE American: GUNN) (TSX: GCU) (OTCQB: GCUMF) (FSE: 3XS0) an American copper producer headquartered in Phoenix, Arizona, is pleased to announce initial assay results from its ongoing 2026-2027 drilling program at the flagship Gunnison Copper Project and its high-grade Strong & Harris satellite deposit in southern Arizona. Results include a significant high-grade copper-zinc-silver massive sulfide intersection at Strong & Harris, alongside continued advancement of the Company’s robust metallurgical testing program. The results of SHM-2 confirm the high-grade mineralization in the resource model and highlight the potential for additional high-grade mineralization within the broader Gunnison district as the Company advances technical studies.

Highlights

• High-grade massive sulfide intersection at Strong & Harris: Drill hole SHM-2 intersected 40 feet grading 5.15% copper, 11.99% zinc and 16.38 g/t silver (approximately 0.53 oz/t) within a broader mineralized interval of 311 feet grading 1.39% copper and 2.29% zinc, confirming a high-grade zone represented in the existing resource model.
• Broad copper mineralization at the Gunnison Project: Drill hole NSM-18 intersected 790.3 feet grading 0.46% copper, while NSM-22 intersected 738.3 feet grading 0.43% copper.
• Drilling program advancing: A total of 27,953 feet of drilling across 25 holes has been completed at Gunnison and Strong & Harris as part of the planned approximately 138,000-foot, 120-hole program.
• Comprehensive metallurgical program underway: Testing across seven laboratories is evaluating heap leaching, sulfide leaching, material sorting, flotation and solvent extraction to support process optimization and the ongoing technical report.

Craig Hallworth, President and CEO of Gunnison Copper, commented:

“These initial drilling results reinforce the significant potential of our Gunnison district, particularly at Strong & Harris, where we have confirmed the high-grade copper-zinc-silver mineralization in our resource model, including 40 feet grading over 5.1% copper and 12.0% zinc. Our drilling and metallurgical programs are building the technical understanding needed to evaluate how this mineralization could contribute to Gunnison’s development.”

“Our next priority is to understand how best to recover that metal. Flotation testing is evaluating a potential concentrator route for sulfide material, including opportunities to recover zinc and silver alongside copper, while our heap-leach program continues to advance the flagship Gunnison Project oxide copper. By advancing these initiatives in parallel, we are positioning Gunnison to become a major source of American copper production.”

Strong & Harris – High-Grade Copper-Zinc-Silver Mineralization

Drilling at Strong & Harris has intersected significant copper-zinc mineralization, including a high-grade massive sulfide interval in hole SHM-2, confirming a high-grade zone represented in the existing resource model.

Hole SHM-2 returned 311 feet grading 1.39% copper, 2.29% zinc and 6.41 g/t silver, including 40 feet grading 5.15% copper, 11.99% zinc and 16.38 g/t silver.

Additional drilling in SHM-1 and SHM-3 intersected copper-zinc mineralization, providing further information for the Company’s ongoing technical evaluation of the deposit.

Figure 1: Drill Core from SHM2-1 (586 to 588 feet)

 Figure 2: Drill Core from SHM2-1 (588 to 590 feet) 

Drilling Results

The Company’s ongoing drilling program is designed to support resource definition, metallurgical characterization, expansion and exploration across the Gunnison Project and Strong & Harris deposit.

Table 1: Selected Drill Results

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Estimated true thicknesses are calculated using drill-hole orientation and interpreted formation dip. Drill intervals are reported as downhole lengths

Evaluation of a Potential Concentrator Processing Route

In parallel with heap-leach optimization, the Company is conducting flotation testing at FLSmidth to evaluate a potential concentrator processing route for sulfide mineralization at Gunnison and Strong & Harris, including the high-grade copper-zinc-silver mineralization intersected in SHM-2. This work will assess the potential to recover sulfide copper and zinc into saleable concentrates and silver as a payable byproduct with processing into finished metal intended to be performed in the United States.

The flotation program addresses sulfide processing options, while material-sorting and heap-leach testing evaluate the planned leach processing route. Reported assay grades do not establish metallurgical recoveries, concentrate quality, byproduct payability or suitability for heap leaching. Further test work and technical and economic evaluation are required to determine whether a concentrator could form part of a future development plan.

2026-2027 Drilling Program Progress

Gunnison continues to advance its planned ~138,000-foot drilling program across the Gunnison Project and Strong & Harris deposit, comprising resource, metallurgical, expansion and exploration drilling.

To date, the Company has completed ~28,000 feet across 25 drill holes, representing approximately 20% of the total planned footage.

Table 2: Gunnison Drilling Progress

Table 3: Strong & Harris Drilling Progress

Table 4: 2026-2027 Drill Plan Progress

Table 5: Drill Hole Locations and Orientations

Sampling, Analytical Methods and QA/QC

All samples are prepared from manually split or sawn PQ core sections on site in Arizona. Split drill core samples are then sent to independent laboratory ALS Global in Reno, Nevada for Total Copper and Sequential Copper analyses. Standards, blanks, and duplicate assays are included at regular intervals in each sample batch submitted from the field as part of an ongoing Quality Assurance/Quality Control Program. Pulps and sample rejects are stored by Gunnison for future reference.

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 main pit Measured and Indicated Mineral Resource containing over 846 million tons with a total copper grade of 0.33% containing 5.19 billion pounds of copper (Measured Mineral Resource of 192 million tons at 0.37% containing 1.42 billion pounds of copper and Indicated Mineral Resource of 655 million tons at 0.31% containing 3.77 billion pounds of copper).

The Strong & Harris satellite deposit, located approximately 1.9 miles from the Gunnison processing facilities, is also included in the mine plan and hosts an Inferred Mineral Resource of 76 million tons grading 0.49% total copper (0.32% CuOx) at a 0.07% cutoff, 0.56% zinc and 0.12 oz/ton silver, containing approximately 740 million pounds of copper, including 483 million pounds of oxide copper, as well as zinc (856 million pounds) and silver (9.0 million ounces).

A preliminary economic assessment was completed in March 2026 for the Gunnison Project yielding robust economics including an NPV8% of $2 billion, IRR of 22.5%, and payback period of 3.9 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.

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

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

For additional information on the Gunnison Project please refer to the technical report titled “Gunnison Project NI 43-101 Technical Report, Preliminary Economic Assessment, Cochise County, Arizona, USA” with an effective date of March 18, 2026 filed on SEDAR+ at www.sedarplus.ca.

For additional information on the Johnson Camp Mine please refer to the technical report titled “Johnson Camp Mine NI 43-101 Technical Report, Cochise County, Arizona, USA” with an effective date of March 18, 2026 filed on SEDAR+ at www.sedarplus.ca.

Dr. Roland Goodgame, Senior VP of Project Development of the Company is a Qualified Person as defined by NI 43-101. Dr. Goodgame has reviewed and approved the technical information contained in this news release.

Dr. Goodgame has reviewed and verified technical data disclosed in this news release and has not detected any significant QA/QC issues during review of the data and is not aware of any sampling, recovery or other factors that could materially affect the accuracy or reliability of the drilling data referred to herein. The verification of data underlying the disclosed information includes reviewing compiled assay data; QA-QC performance of blank samples, duplicates and certified reference materials; and grade calculation formulas.