Australian critical minerals developer Cobalt Blue Holdings Ltd. and startup Regeneration Enterprises want to change the mining industry's attitude toward legacy assets, which Rio Tinto Group has called its biggest liability.

The partners are working on technology to allow re-treating tailings to extract more metals and mitigate environmental impacts of past mining. They argue it should become a larger focus in meeting green technologies' increasing demand for critical minerals in the coming decades.

Regeneration was created in November 2021 when Rio Tinto partnered with Washington, DC-based nonprofit RESOLVE and committed to investing $2 million in extracting valuable minerals and metals from mine tailings, waste rock and water. Earnings will be reinvested in habitat restoration and closure activities. Regeneration also plans to create and trade biodiversity and carbon credits through the rehabilitation of land.

The global mining industry produces an estimated 100 billion metric tons per year of waste that, when managed badly, creates environmental and safety risks and ongoing liabilities long after mines close, according to a November 2023 report by the Australian government.

Cobalt Blue, which has been doing test work on Australian and Canadian tailings sites since launching in 2021, signed a memorandum of understanding with Regeneration on March 27 to convert mine waste into metals vital to the energy transition.

Helen Degeling, who leads Cobalt Blue Holdings' waste streams project. Source: Cobalt Blue Holdings.

Mine closure was Rio Tinto's biggest liability in 2020 at $13.3 billion, according to a 2021 presentation, and this figure grew to $17.2 billion at the end of 2023. Cobalt Blue's patented minerals processing technology for treating pyrite will be used to help extract value from these sites. The new partnership is "critical," Nicolau Barros, Regeneration's senior director of engineering and site solutions, told S&P Global Commodity Insights.

"As an industry, we don't do mine closure and rehabilitation very well, and behind the scenes I've had many conversations with others saying it's a real gap in our industry," Helen Degeling, Cobalt Blue's project acquisition manager, told Commodity Insights.

"Everybody just puts their mine on care and maintenance or tries to sell it so they're not stuck with that liability," said Degeling, who leads Cobalt Blue's waste streams project.

Innovation as business

Australia has "tens of thousands of inactive and unrehabilitated mine sites but only 15 examples of repurposed mined land," the November 2023 government report said.

"That legacy then ends up in the hands of the taxpayer when sites are abandoned," Degeling said. "But many of these sites still contain valuable metals as well as other raw materials that can be used in other industries. Our opportunity lies in not only extracting the remaining value but also in removing the harmful acid-forming minerals to reduce the remaining risk to the environment and cost of ongoing management of the site."

Thus, Regeneration's biggest innovation is its business model, according to Barros.

"We're looking to re-mine, reprocess and ultimately bring critical metals to market to primarily promote restoration and uplift socioeconomic aspects of the communities in the vicinity, including traditional owners," Barros said. "That makes Regeneration unique to what others are doing in the industry, and how we partner with companies like Cobalt Blue."

Nicolau Barros, senior director of engineering and site solutions at Regeneration Enterprises. Source: Regeneration Enterprises.

"Cobalt Blue's technology enables the opportunity to treat the residual pyrite in mining waste materials that could be a source of acid to natural bodies of water. And then you have the opportunity to extract cobalt with it just as you would have opportunities to extract other metals as well," Barros said.

Barros was formerly the manager of Rio's mine closure studies and ran operations planning for BHP Group Ltd.

"With Rio Tinto as a catalytic founding partner, we've had the opportunity to look into their list of legacy assets to see where we can apply our model and where we can develop a particular business with the Regeneration banner," Barros said. "Cobalt Blue's technology would then be in that mix, along with other technology partners, as enablers in terms of specifically what technologies would be required to re-mine, reprocess and extract the metal in a way that we can actually promote the restoration, along with [the associated] local socioeconomic uplift."

Rio Tinto strategy

For Rio Tinto, whose closure division manages over 90 legacy assets in nine countries and 28 tailings storage facilities, Regeneration will "provide an environment to trial new technologies and drive collaborative research into innovative solutions to contamination problems which could guide the broader industry," according to a 2021 presentation.

As a foundation investor in Regeneration, Rio Tinto welcomed Regeneration's partnership with Cobalt Blue, a Rio Tinto spokesperson said in an email interview.

"We continue to work with Regeneration Enterprises to identify other potential opportunities. This work includes progressing assays from recent drilling at a former copper site in McGill, Nevada, and assessing ecological restoration opportunities there, as well as trials elsewhere on recovering critical minerals from waste," the spokesperson said.