Rio Tinto has produced the first copper from the Johnson Camp mine in Arizona using its Nuton Technology, marking a pivotal step forward in the development of this innovative copper processing technology, the company said.
fter more than 30 years of research and development, the first copper cathode using Rio Tinto’s proprietary bioleaching technology, which relies on microorganisms grown on site, was produced at Gunnison Copper’s Johnson Camp mine last month. The deployment involves the design and delivery of a technology package for a heap leach pad targeting production of approximately 30,000 tonnes of refined copper over a four-year demonstration period. Rio Tinto is engaging with several potential customers in the U.S. to support the domestic copper supply chain.
Rio Tinto Copper Chief Executive Katie Jackson said: “This is a breakthrough achievement for our Nuton technology, which is proving that cleaner, faster, and more efficient copper production is possible at an industrial scale. In an industry where projects typically take about 18 years to move from concept to production, Nuton has now proven its ability to do this in just 18 months. According to Jackson, Nuton has designed a modular system deployed as a technology package integrating biology, chemistry, engineering, and digital tools, allowing it to be rapidly scaled and tailored to different ore bodies, unlocking resources that have historically been considered uneconomic or challenging. „We are actively partnering on projects in North and South America to assess the potential for future deployment at additional sites in the coming years”, Jackson said.
Nuton relies on naturally occurring microorganisms to extract copper from primary sulphide ores, which are traditionally difficult to process. These microbes, grown at large scale in Nuton’s proprietary bioreactors, accelerate the oxidation of minerals in the crushed ore heap, generating heat and enabling copper to dissolve into a leach solution, which is then processed into 99.99% pure copper cathode.
Significantly, processing copper ore with Nuton eliminates the need for concentration, smelting and refining, shortening supply chains and delivering copper cathode at the mine gate. It achieves recovery rates of up to 85% from primary sulphides, the most abundant copper bearing ores in the world.
Nuton can also extend mine life and maximize resource use
According to Rio Tinto, Nuton can also extend mine life and maximize resource use by extracting value from ores that would otherwise be classified as waste, increasing yield and revenue at both new and existing mines. Its environmental performance is expected to exceed conventional copper processing technologies, with up to 80% less water usage and up to 60% lower carbon emissions than the traditional concentrator route.
At Johnson Camp, Nuton aims to produce copper with the lowest carbon footprint in the U.S. Through the purchase of 134,000 Green-e Energy certified renewable energy certificates, Nuton ensures 100% of the site’s electricity is matched by renewable sources. The copper produced is anticipated to have a mine-to-metal carbon footprint of 0.82-kilogram CO₂-e per kilogram copper, the lowest in the U.S. and substantially lower than the projected 2026 global average of 3.4 kilograms CO₂-e per kilogram among operating copper mines. Additionally, water intensity is anticipated to be 71 litres per kilogram copper, compared to the global average industry estimate of ~130 litres per kilogram of copper production.
The next phase will focus on validating long-term technical performance. This includes multi-year testing, independent third-party verification, and internal review by Rio Tinto to ensure consistent recovery rates and environmental performance.
Source: Rio Tinto
