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When easy options run out, industries get inventive. That’s where copper miners find themselves. Faced with vigorous demand, they are increasingly going after material from old sites, or ore once deemed too difficult to use.
Rio Tinto’s new leaching arm, Nuton, is using microorganisms to extract the red metal from ores that are traditionally tough to process, and has signed up Amazon as its first customer. Freeport-McMoRan aims to produce around 363,000 tonnes of copper a year by 2030 from its new leaching initiatives, using either acidic solutions, heat, or a combination of the two to isolate copper. That production alone ranks among the world’s top 20 copper mines.
This invention is the result of necessity. Copper demand is projected to soar, thanks to its use in AI data centres and electricity grids. But traditional sources are dwindling. BHP thinks existing mines will produce 15 per cent less copper in 2035 than they did in 2024, and that the 30 largest undeveloped greenfield projects in the world will add just 5mn tonnes of copper — 18 per cent of current production — by 2035.
Leaching low-grade ore therefore looks more and more attractive. The average marginal copper mine, processing copper in a regular concentrator, breaks even when the copper price is about $8,000 per tonne according to Bernstein Research, compared with $13,000 now on the London Metals Exchange.By contrast, Rio reckons Nuton’s technology is roughly 40 per cent cheaper to run than the processes at conventional mines.
Add in the fact that leaching requires less in the way of upfront capital spending, and waste-based copper miners could break even at about $4,000 per tonne. The cost of Freeport’s leached copper, too, works out at about half of its cost from regular concentrated copper, according to Bernstein calculations. That means miners get a lot of change out of current prices.
Miners didn’t pile into these technologies before, because there was little need while easy-to-reach oxides were still plentiful. Big companies usually prefer to pour their energy into projects that move the needle. Now, though, Goldman Sachs estimates that the process could boost the five biggest copper miners’ production by a combined 1mn tonnes of the metal each year by 2034. That’s only a fifth of the shortfall Goldman expects by 2030, but it is still a sizeable amount.
There is a broader lesson, too, about shortages. Projections about the future availability of commodities, alongside periodic scare stories about how the planet may be forced to do without, tend to ignore just how clever operators can be when forced to squeeze their brain cells — and their piles of rubble — for new ideas.