The mine was restarted as a proving ground for Rio Tinto's new method of unlocking low-grade copper deposits. Rio signed a two-year supply pact with Amazon Web Services, a vote of confidence for its Nuton venture, which uses bacteria and acid to extract copper from ore that was previously uneconomical to process. The move by Amazon is the latest example of a technology company rushing to secure the power and critical materials necessary to build and operate artificial-intelligence data centers. The Nuton copper will satisfy only a sliver of Amazon's needs. The biggest data centers each require tens of thousands of metric tons of copper for all the wires, busbars, circuit boards, transformers and other electrical components housed there. The 14,000 metric tons of copper cathode that Rio expects the Arizona Nuton project to yield over four years wouldn't be enough for one of those facilities.
Rio deployed its bioleaching process in the recent restart of a mine east of Tucson and has partnerships to take the technology to several others in the Americas. The idea is to uncork the low-grade ore left behind at old mines and is key to Rio's plans to boost output when new discoveries are harder than ever to bring online and copper demand is surging. [...] "We work at the commodity level to find lower carbon solutions to drive our business growth," said Chris Roe, Amazon's director of worldwide carbon. "That means steel, and that means concrete, and it absolutely means copper with regard to our data centers." Roe said the copper will be routed to companies that produce components for Amazon's data centers. As part of the deal, Amazon is supplying Rio with cloud-computing and data analytics to optimize Nuton's recovery rates and help the miner expand production.
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