Gunnison Copper (TSX: GCU; NYSE-A: GUNN) has confirmed a high-grade copper-zinc zone at its Strong & Harris deposit in Arizona as it tests whether a concentrator could add another processing option to its development plans.
Drill hole SHM-2 cut 94.8 metres grading 1.39% copper and 2.29% zinc from 160 metres depth, the company said Tuesday. That included 12.2 metres of 5.15% copper, 11.99% zinc and 16.38 grams silver per tonne from 175.6 metres
“Our next priority is to understand how best to recover that metal,” CEO Craig Hallworth said Tuesday.
The drilling confirms mineralization already represented in the resource model. Flotation tests will assess whether sulphide material can yield saleable copper and zinc concentrates, with silver as a payable byproduct. Recoveries and economics must be established before a concentrator could enter a development plan.
Processing options
The Gunnison project lies about 100 km east of Tucson. Its March preliminary economic assessment envisaged open-pit mining and heap leaching, followed by solvent extraction and electrowinning to produce finished copper cathode. The study includes inferred resources, and its economic conclusions remain preliminary.
Strong & Harris held 69 million inferred tonnes at 0.49% copper, 0.56% zinc and about 4.1 grams silver as of Jan. 23, containing about 335,700 tonnes copper, 388,100 tonnes zinc and 9 million oz. silver, according to the March technical study.
Gunnison estimates the true thickness of the 94.8-metre intersection at 82.1 metres and the richer 12.2-metre interval at 10.5 metres.
The company already produces copper at nearby Johnson Camp, where it is demonstrating Rio Tinto’s (NYSE, LSE, ASX: RIO) Nuton leaching technology. Nuton agreed in September to pay Gunnison $8 million (C$11.3 million) after the partners expanded the plan to mine additional material during the 2027–2029 demonstration period.
Gunnison shares fell 1.3% to C38.5¢ apiece Tuesday morning in Toronto, valuing the company at about C$198 million ($141 million). The stock has traded between 27.5¢ and 70¢ apiece over the past year.
