Rio Tinto’s Nuton technology produces first copper

Rio Tinto has successfully produced its first copper using its Nuton technology at the Johnson Camp mine in Arizona and, according to the company, has thereby taken a decisive step in the development of this efficient and environmentally friendly copper processing technology.

Following more than 30 years of research and development, the first copper cathode was produced last month at Gunnison Copper’s Johnson Camp Mine using the bioleaching technology developed by Rio Tinto, which is based on microorganisms cultivated on site. The project involves the development and supply of a technology package for a heap leaching plant, which is expected to produce around 30,000 tonnes of refined copper over a four-year demonstration period. Rio Tinto is working with several potential customers in the US to support the domestic copper supply chain.
Katie Jackson, Chief Executive of Rio Tinto Copper, said: “This is a groundbreaking achievement for our Nuton technology, proving that cleaner, faster and more efficient copper production on an industrial scale is possible. In an industry where projects typically take around 18 years to progress from concept to production, Nuton has now demonstrated that this can be achieved in just 18 months. Nuton has developed a modular system that is deployed as a technology package, integrating biology, chemistry, engineering and digital tools. According to Rio Tinto, this allows it to be scaled up rapidly and adapted to different ore bodies, thereby enabling the development of resources that were previously considered uneconomic or difficult to mine. “We are actively involved in projects in North and South America to assess the potential for future deployment at further sites in the coming years,” said Jackson.
The technology utilises naturally occurring microorganisms to extract copper from primary sulphide ores, which are traditionally difficult to process. These microbes, which are cultivated on a large scale in Nuton’s proprietary bioreactors, accelerate the oxidation of the minerals in the crushed ore pile, generate heat and enable the copper to dissolve into a leachate, which is then processed into 99.99 per cent pure copper cathodes.
Processing copper ore using Nuton eliminates the need for concentration, smelting and refining, thereby shortening supply chains and enabling copper cathodes to be delivered directly from the mine site. According to the company, the process achieves recoveries of up to 85 per cent from primary sulphides, the most common type of copper-bearing ore worldwide.

Nuton extends mine life and maximises resource utilisation

Nuton can also extend mine life and maximise resource utilisation by extracting value from ores that would otherwise be classified as waste, thereby increasing output and revenue at both new and existing mines. Rio Tinto expects the environmental performance of Nuton technology to surpass that of conventional copper processing technologies, with up to 80 per cent less water consumption and up to 60 per cent fewer CO₂ emissions than the traditional concentrator route.
The next phase of Nuton will focus on validating its long-term technical performance. This will involve multi-year trials, independent third-party audits and internal audits by Rio Tinto to ensure consistent recovery rates and environmental performance.
Source: Rio Tinto