Jetti Resources’ technology could help unlock millions of tonnes of copper from tailings

A new technology by Jetti Resources that can be used to extract copper from mine waste could be a “game-changer” for the copper industry, says Mike Outwin, Jetti’s CEO and co-founder.

“The technology enables the recovery of copper trapped in primary sulphide ore usually discarded as waste by miners because of the low copper yields generated from conventional processing methods,” Outwin said in an interview. 

Capstone Mining (TSX: CS) is the first company to validate the effectiveness of Jetti’s technology on a commercial scale at its Pinto Valley open-pit copper mine in Arizona. 

Japan’s Mitsubishi, through its Mineral Resources Group, has supported the commercialization of the technology since 2019 and holds an undisclosed stake in the company. Earlier this month it increased its ownership in the company and invested US$50 million, which also included funds from first time investors BHP Ventures, Freeport-McMoRan (NYSE: FCX), and global investment firm Orion Resources Partners.

Mitsubishi will “provide our expertise in business creation, marketing, finance, and technology and collaborate to expand the deployment of Jetti’s technology across the industry,” Takashi Hirose, general manager of Mitsubishi’s Mineral Resources Group, wrote in an email to The Northern Miner. 

“Jetti’s technology has the potential to make a significant contribution to more efficient development and conservation of the world’s limited copper resources,” Hirose noted. “Our investment was made to both secure a stable supply of copper and to contribute to MC’s efforts in addressing the problem of diminishing natural resources.” 

The success at Capstone’s Pinto Valley has “deepened our confidence in Jetti’s technology, and we are impressed with the great performance of Jetti’s management team,” he added.

Following the latest financing, Jetti has now raised more than US$100 million for the development and deployment of the technology. 

“We’re looking forward to pursuing opportunities within our partners’ portfolios of copper assets to deliver additional copper to the markets and value to our investors,” Outwin said.  

Last year Jetti strengthened its board and management team, bringing on Chip Goodyear, the former CEO of BHP(NYSE: BHP; LSE: BHP; ASX: BHP), and Trevor Reid, the former CFO of Anglo-Swiss mining company Xstrata, which was acquired by Glencore (LSE: GLEN) in 2013. 

Capstone Mining first deployed the catalytic technology in mid-2019 in an effort to enhance copper recovery from the leach operation at Pinto Valley.  

Last year, the company reported a doubling of copper cathode production per area irrigated, a key metric for tracking the performance of its leaching operation, since the technology was implemented at the mine’s solvent extraction and electrowinning (SX-EW) plant. 

“We were very excited by the results as it means we can now generate value from material previously considered waste,” Jerrold Annett, Capstone’s senior vice president, strategy and capital markets, said in an interview. “We have historic stockpiles potentially containing over a billion pounds of copper. So, there is huge potential to improve the competitiveness of Pinto Valley.” 

Another “big win for us,” Annett said, is the ability to produce a finished cathode product with a 99.99% copper content on site. By comparison, copper concentrates from the site’s mill may only contain around 25% copper, he said, and are currently sent by Capstone for refining at smelters that are often some distance from the site.

In 1981, Pinto Valley started producing copper cathode from stockpiled material below the mill’s cut-off grade that had accumulated since the early 1970s. By the early 2000s, annual cathode production averaged approximately 16 million pounds.  

Since then, however, annual production has fallen to around four million lb. of copper due to reduced leach recovery from the chalcopyrite mined at the operation.    

Capstone’s use of the catalytic leach technology was an extension of its existing PV3 optimization study, which focused on several low-capex, high-impact projects to increase the net present value of the operation.

Jetti’s technology could enable existing SX-EW operations to process mineralised material previously considered too low-grade to be processed economically, reinvigorating aging mining operations while also providing an alternative to the development of brownfield sites.

“A key aim of PV3 was to generate strong cash flow from the site’s underutilized 25 million pounds per year SX-EW plant, which is currently operating at around 20% capacity,” Annett said.

The company plans to increase copper cathode production from its SX-EW facility to around 300-350 million lb. of copper over the mine’s remaining 19-year mine life, and given the commercial demonstration of the technology, Capstone intends to significantly expand leaching activity at the facility, targeting the estimated 280-300 million tonnes of historic stockpile and the estimated 175-185 million tonnes of high-grade waste that will be deposited at Pinto Valley over the rest of its operational life.

“There is also potential to increase the mill cut-off grade to bolster copper concentrate production, which would also increase the amount of high-grade waste available for leaching,” said Annett. 

Capstone is working on an updated study, PV4, which, he said, will include increased use of Jetti’s technology to reduce waste tonnes, increase production, and extend the life of the mine, possibly into the 2050s.

The study is expected to be completed in the second half of 2022. 

Currently, around 70% of the world’s copper resources are bound up in primary sulphide minerals like chalcopyrite, the world’s most abundant copper-bearing mineral.

However, standard leaching techniques, such as heap or run-of-mine leaching with sulphuric acid, used to extract the copper from the chalcopyrite results in a hard, non-reactive coating, which forms around the crystal structures in the mineralised materials. 

“This coating, called the passivation layer, prevents contact between the leaching solution and the surface of the mineral, inhibiting the recovery of copper,” explained Outwin. 

Over the past decade or so, the mining industry has sought to develop a cost-effective method for extracting copper from low-grade sulphide ore. These efforts have typically focused on subjecting the chalcopyrite to high temperatures or crushing it very finely to extract the copper before the passivation layer forms; however, this approach has proved to be expensive and uneconomic at scale.

“As miners usually assign zero percent recovery to the low-grade chalcopyrite, which often makes up a significant component of their mines, our technology could be a game-changer for the copper industry,” said Outwin. “It’s considered the ‘holy grail’ for the industry.” 

Developed in collaboration with the University of British Columbia (UBC), the catalytic leach technology uses a proprietary catalyst that enhances copper recovery from heap leaching of chalcopyrite ore. (Under the partnership with UBC, Jetti holds the global license to deploy the technology.) 

It works by disrupting the metal-sulphur bond in the chalcopyrite and prevents the passivation layer from forming, allowing the copper to be extracted unimpeded. It can also remove the passivation layer if it has already formed, allowing for the re-treatment of previously leached material. 

The technology allows for the efficient and effective heap and stockpile leach extraction of copper trapped in the mineralised material, said Outwin, increasing yields by as much as 300% compared to traditional processes. 

“It also easily integrates with existing SX-EW process infrastructure, and so requires minimal additional upfront capex other than the installation of an on-site catalyst addition facility, resulting in lower unit costs of production,” he said. 

In addition to the potential economic benefits, he added, the technology has significant environmental benefits too. 

By using hydrometallurgical methods, processing plants that use the technology require less power and transportation compared with pyrometallurgy. As a result, Jetti estimates that 40% fewer carbon dioxide emissions and 70% fewer emissions of sulphur oxides and nitrogen oxides are generated, and consume less than half the water of traditional pyrometallurgical methods to produce the same amount of copper.  

“The widespread adoption of the technology by the copper industry could also reverse the decade’s long decline in the use of leaching and SX-EW to produce copper, which has been occurring due to falling reserve quality and lower orebody grades,” said Outwin.  

There are several types of mining operations and deposit categories where the technology could be deployed, he said. 

These include at SX-EW plants with underutilized capacity or mines with mineralised material below cut-off grades, which could allow for the inclusion of stockpiled material in mine plans. The technology could also enable low-grade material processing at greenfield deposits with large amounts of sulphide ore presently considered uneconomic to process. Higher-grade sulphide tailings would also benefit from the technology.  

“It has the potential to extend the life of a mine by allowing waste streams and uneconomic deposits to be turned into valuable assets through the conversion of resources into reserves,” said Outwin. 

According to a study by CRU Group commissioned by Jetti, there is a decade’s worth of copper contained within discarded waste dumps at mines around the world. 

Released in May, the study estimated that nearly 40 million tonnes of copper are currently bound up in tailings. 

As the world transitions to a low-carbon economy, global demand for the red metal, which is crucial to the electrification of the transportation and power systems needed to support this transition, is expected to soar over the coming decades. 

CRU forecasts a significant supply gap emerging from the mid-2020s, which could reach nearly 11 million tonnes annually by 2050 if new supplies don’t come online. 

The consulting company estimates the cumulative total market demand for Jetti’s technology could be about 234 million tonnes of copper by 2050. Were the technology to be applied to 100% of this demand, CRU estimates, the technology could yield a peak production of 7.2 million tonnes of copper per year by 2034, enough to meet most of the forecast supply shortfall.

The study highlights the “huge contribution our technology can make in providing the copper vital for de-carbonizing the world’s economies,” said Outwin. “Furthermore, the technology also enables the production of copper in a cost-effective and environmentally sustainable manner.”   

Jetti currently has a pipeline of 23 projects at various stages of development, including five active pilots and three opportunities transitioning to commercial status, he said. “We’re now in full-blown execution mode and are hard at work scaling up our growth phase.”