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Copper miners are turning to vast waste piles, novel extraction technologies and even bacterial “bugs” in an effort to increase production of the critical mineral that has surged in price.
BHP, Rio Tinto, Freeport-McMoRan and Vale Base Metals are among those researching and deploying new techniques to recover metal from old and disused sites, or from material previously viewed as too difficult to use.
Vicky Peacey, president of the giant Resolution mine being developed by Rio and BHP in Arizona, said extracting the once unrecoverable copper stored in giant waste mounds was the industry’s “holy grail”, while mining group VBM described it as “the next frontier”.
The interest in waste comes as miners race to grow their copper businesses in the context of record prices of more than $13,000 per tonne, which have prompted some of the world’s biggest miners to pursue mergers.
Rio Tinto and Glencore this month confirmed they had resumed talks over a potential deal to create the world’s largest mining company, while Anglo American and Teck Resources agreed a $60bn combination last year.
The highly conductive industrial metal is used in everything from household appliances to cabling, grid infrastructure and the data centres that will power the predicted AI boom. Demand is expected to outstrip supply by a substantial margin in the 2030s at current rates.
That dynamic, combined with accidents that caused disruptions at large mines, has driven the benchmark London copper price to several record highs since October.
While miners are racing to increase production, developing new mines is a hugely expensive and time-consuming process. This has pushed them to explore innovative ways to produce the metal and to squeeze more out of existing operations.
Kathleen Quirk, Freeport chief executive, said the application of new leaching technology could provide about two-thirds of the growth in the company’s US copper production by 2030.
“Now we have technology that allows us to find where the copper is in these stockpiles,” she told the FT. The effect on production of deploying the process at its US sites was “the equivalent of a big new mine”, she explained.
Leaching involves adding an acidic solution to mined material that extracts the copper from the other minerals. The use of such technologies at waste stockpiles and on old low-grade material has become a more appealing prospect as technologies and the economics of the process have improved.
In Arizona, BHP is also looking into whether it can extract copper from tens of thousands of tonnes of waste material stacked in mountainous layers. That could allow old sites to become “an important additional source of copper as demand soars and supply dwindles”, said BHP chief technical officer Johan van Jaarsveld.
Meanwhile, Rio Tinto said in December that it had produced industrial-scale quantities of copper for the first time with an innovative method that uses microorganisms, and which it began developing in the 1990s.
Microbes developed by its Nuton venture and grown in bioreactors are added to piles of crushed ore to accelerate the chemical reactions during leaching and make the process more effective.
Rio Tinto this month said Amazon Web Services would become Nuton’s first customer, with the cloud computing group set to use the copper in its US data centres.
“It’s fascinating what these little bugs or bacteria can do,” said Harald Muller, Nuton chief technology officer. “They’re naturally occurring but have been adapted to our conditions over the last 30 years.”
Katie Jackson, Rio copper chief, said the technology was a potential “game-changer for the industry”, adding that there was “a lot of interest and a lot of desire for this to work”.
In the US, the government has directed agencies to map out domestic mine waste and take steps to make it easier to use. “Critical minerals exist in substantial quantities in mine waste across the nation,” the interior department said in July. “We have the resources within our borders to reduce our dependence on imports.”