Key Highlights

  • BHP (ASX:BHP) is testing a technology that extracts copper from the water left behind at old mine sites.
  • BHP Group (ASX:BHP) has partnered with SiTration, a spin-out from the Massachusetts Institute of Technology, to trial a novel copper-recovery technology at its historic
  • The pilot is structured in two stages.
  • SiTration’s approach is designed to recover critical minerals from dilute and complex material streams that conventional methods struggle to process economically.

BHP (ASX:BHP) is testing a technology that extracts copper from the water left behind at old mine sites. Developed by an MIT spin-out, the pilot in Arizona hints at a future where legacy Assets become new sources of critical minerals, though it remains an early-stage experiment rather than a proven business.

What BHP Is Trialling

BHP Group (ASX:BHP) has partnered with SiTration, a spin-out from the Massachusetts Institute of Technology, to trial a novel copper-recovery technology at its historic Copper Cities site in the Globe-Miami Mining district of Arizona. The two companies announced in August 2026 the launch of two pilot deployments to test SiTration’s technology, which aims to extract copper from legacy mining water, the water left behind at old mine sites, and turn it into a usable product.

The pilot is structured in two stages. An initial small-scale trial, running over about one month, is designed to validate the continuous, autonomous production of copper from the legacy water. A larger deployment planned for later in the year aims to produce up to two tonnes of commercial-scale copper cathodes over a two-month period. Copper Cities is a fitting testbed: it was an active mine that produced close to 400,000 tonnes of copper between the 1950s and early 1980s.

How the Technology Works

SiTration’s approach is designed to recover critical minerals from dilute and complex material streams that conventional methods struggle to process economically. In bench-scale testing using real feedstock from Copper Cities, the company has already demonstrated production of LME Grade A copper, the London Metal Exchange’s benchmark high-purity standard. Notably, these preliminary tests used no chemicals, generated no new waste products, and consumed relatively little energy, below 3 to 4 kilowatt-hours per kilogram of copper recovered.

For a general reader, the appeal is twofold: the process potentially turns a waste stream into a valuable product, and it does so in a way that appears environmentally cleaner than traditional extraction. Both features align with the direction the mining industry is trying to move.

Why It Matters for Copper Supply

The context is copper’s looming Supply challenge. SiTration’s chief executive, Brendan Smith, has argued that the American Southwest holds legacy mining water containing billions of dollars’ worth of copper, and pointed to projections that global copper Demand could grow by around 70 per cent by 2050 to support the build-out of energy infrastructure and data centres. Recovering copper from legacy sources could bolster domestic supply chains while producing metal at the low end of the global cost curve.

This dovetails with BHP’s broader copper strategy. With the company betting heavily on rising copper demand from electrification and artificial intelligence, any technology that could add supply, particularly cheap, low-impact supply from assets BHP already owns, is strategically interesting.

Turning Legacy Assets Into Resources

Perhaps the most intriguing implication is what the pilot suggests about legacy assets. Mining companies hold numerous old or closed sites that carry environmental liabilities and rehabilitation obligations. If technologies like SiTration’s can economically recover metal from the water and waste at such sites, those liabilities could partly transform into resources. BHP’s Legacy Assets team and BHP Ventures are involved precisely to explore this potential, testing the technology under real operating conditions.

The environmental dimension matters here too. Treating mining-impacted water to recover copper could, in principle, address a legacy environmental issue while generating value, a rare win-win if it proves viable at scale.

The Economics and the Caveats

It is important not to get ahead of the evidence. The Copper Cities pilots are exploratory, designed to generate technical and operational insights rather than to declare commercial success. Bench-scale results, however promising, do not guarantee that the process will work economically at industrial scale. The economics of secondary resource recovery depend on recovery rates, throughput, operating costs and copper prices, none of which are yet established for this technology in a commercial setting.

BHP itself has framed the work in measured terms, describing it as an opportunity to evaluate an innovative approach and better understand its potential. That caution is appropriate: this is a pilot, not a proven production method.

Opportunities and Risks

The opportunity is a potentially cheap, low-impact new source of copper that also helps address legacy environmental liabilities, aligned with strong long-term copper demand. The risks are technological and commercial: the process may not scale economically, recovery volumes may prove modest, and pilot success does not assure a viable business. Investors should treat the technology as promising optionality rather than a material near-term Earnings driver.

What Investors Should Watch Next

The immediate signpost is the outcome of the two pilots, particularly whether the larger deployment can produce commercial-scale copper cathodes as planned. Investors may also be watching whether BHP and SiTration extend the collaboration and how the economics look at scale. A key variable will be whether the technology can move from a promising pilot to an economically viable process across BHP’s and the industry’s many legacy sites, at which point what is today a modest experiment could become a genuinely new pillar of low-impact copper supply.

Key Takeaway

BHP’s pilot with SiTration to recover copper from legacy mining water is an intriguing early-stage experiment that could, if it scales, turn environmental liabilities into new sources of critical minerals. Bench-scale results producing LME Grade A copper without chemicals or new waste are promising, and the strategic fit with rising copper demand is clear. But this remains a pilot, not a proven business. For shareholders, the issue to monitor is whether the technology can achieve economic, commercial-scale production, because only then would it become a meaningful contributor for ASX:BHP.