Rio Tinto (NYSE, LSE, ASX: RIO) venture partner Nuton has produced the first copper using its unique sulfide bioleaching technology at Gunnison Copper’s (TSX: GCU) Johnson Camp Mine (JCM) in Arizona last month. This milestone is part of a four-year demonstration period at JCM, which uses the mine’s heap leach pad to produce approximately 30,000 tonnes of refined copper. JCM is located about 105 km east of Tucson. Rio Tinto Copper CEO Katie Jackson stated this breakthrough proves cleaner, faster, and more efficient industrial-scale copper production is feasible—Nuton’s tech moves from concept to production in just 18 months, versus the industry average of around 18 years.

The achievement follows three months after Gunnison produced its first copper cathode at JCM, making the mine the United States’ newest red metal producer. Nuton’s first cathode results from over 30 years of research and development; the firm began collaboration with Gunnison’s predecessor Excelsior Mining at the site in 2023. On Thursday morning in Toronto, Gunnison shares gained 2.7% to C$0.38 apiece, with a market capitalization of C$146.4 million ($105 million).

Nuton’s technology leverages natural microorganisms cultivated in proprietary bioreactors to extract copper from sulfide ores—typically challenging to process. These microbes accelerate mineral oxidation in the heap leach pad, generating heat that dissolves copper into a leach solution, which is then processed into 99.99% pure cathode. Key advantages include up to 85% recovery rates, elimination of milling, tailings, smelting, and refining steps—shortening supply chains and delivering cathode directly at the mine. It re...