Mining and Process Solutions is developing a range of novel leaching
technologies based on glycine. (Photo: Draslovka)

The company has calculated that under a 1.5°C accelerated energy transition scenario, 9.7 million metric tons (mt) of new copper supply is needed over 10 years from projects yet to be sanctioned — the equivalent to nearly a third of current refined consumption — if the industry is to meet the climate targets set out in the Paris Agreement.

Approximately 17 million mt of annual copper production is currently in the project pipeline — nearly double the volume required to limit warming to 1.5°C. However, Wood Mackenzie warns that many of these projects have not been developed due to poor economics, and even those that can offer an attractive return on investment have other political, social and environmental hurdles to overcome.

Developing viable solutions to extract complex, lower grade deposits that have traditionally been thought of as uneconomic or unfeasible to process at scale, all with a minimal environmental and social footprint, will be key to mitigating a shortfall in supply. The urgency is real, and technology and equipment providers are teaming up with researchers and mining companies to accelerate testing and adoption.

The result has been a flurry of funding and project announcements over the past 12 months. Jetti Resources, which has developed a breakthrough leaching technology for primary copper sulphide ores, announced in October 2022 that it had raised $100 million in its Series D financing. The funds will be used to continue rapid deployment of the technology at large copper mines.

Jetti signed an agreement with Teck Resources earlier in the year to evaluate the technology’s applicability at “a number of assets with potential copper resources outside of existing mine plans.” The technology integrates seamlessly with existing leach circuits to recover copper trapped in ore which the companies said was “previously not considered for traditional processing.” Teck has also made an investment in Jetti to support testing and further deployment of the technology at its sites.

Finding New Value Through Leaching
Mining and Process Solutions (MPS), a subsidiary of Draslovka, is also developing novel leaching technologies based on glycine. The company is focused on turning waste into value by unlocking low-grade copper ores, particularly those where traditional leaching is prohibited due to environmental or social sensitivities, carbonate- hosted copper oxides that can’t be effectively leached with acid, legacy tailings containing residual valuable metals or cleaning tails from flotation operations.

There is a significant opportunity to fast-track new
copper projects and to find value in materials that
are currently considered to be ‘waste.’
(Photo: Draslovka)

In the short term, Bryan believes that the greatest opportunity, both from a financial and an environmental, social and governance (ESG) perspective, are wasteto- value opportunities. “But longer term, we see that mines are going to be deeper, there will be higher virgin rock temperatures and stresses and a shift towards mechanized and automated mining operations,” he said. “There is an opportunity to introduce ESG-friendly leaching systems accelerated by heat — known as in-mine leaching — where rock is mined and leached underground. Rather than expending energy to bring low-value material to the surface, only a highly concentrated solution or interim product is brought to the surface for extraction and refining. Eventually, there is even the potential for in-situ leaching whereby people don’t have to go underground or use toxic reagents.”

Glycine is an amino acid — one of the building blocks of life — it’s harmless (even edible) and sold over the counter in pharmacies worldwide as a high purity product but also in bulk. It’s also a selective lixiviant and can be used to leach valuable metals, including base metals such as copper and nickel, and precious metals such as gold, silver and palladium. It doesn’t take into solution elements such as iron, aluminum, magnesium and silicon which can make purification and extraction of metals from solution difficult from traditional acid processes and, because the reaction is a complexing one rather than chemical, the glycine itself is not consumed. Theoretically it can be reused over and over, as it stays in the aqueous phase although in practice there will be some losses depending on water management and recovery practices.

“Recycling of reagents provides the opportunity for operators to reduce their costs quite significantly,” said Bryan. “The selectivity can be manipulated through a range of different conditions like pH and dissolved oxygen. Major applications today are in gold, copper, nickel, and cobalt, and more recently we’ve also done work on platinum group metals (PGMs) and poly-metal concentrates. The work on concentrates is considered an alternative to smelting. The premise being that it mitigates the need to transport the concentrate long distances overseas to smelters, driving down greenhouse gas (GHG) emissions significantly and helping to improve supply chain security for a critical metal by producing it domestically.”

Bryan continued: “There are also lots of copper deposits worldwide that contain gold. The flotation process is usually configured to maximize copper recovery and, in doing so, a lot of the gold is sent to tailings. The traditional way to recover that would be using cyanide but, due to residual copper present, cyanide consumptions tend to be really high. With Glycine Leaching technology there is a chance to recover residual gold from both fresh and legacy tailings and create a new stream of value for the mine.” MPS has two heap leach demonstrations coming up in Q1 2023. One is for a carbonate-hosted (limestone) copper oxide deposit in Africa which has been undeveloped thus far due to the economic limitations associated with high acid consumption through traditional acid heap leaching recovery methods.

“We also have an agreement with a very large copper operation in Chile to test the viability of Glycine Leaching on both gold and copper recovery from wastes previously leached,” Bryan explained. “The test work that we’ve done at our partners laboratory in Santiago Chile, has shown we can recover very high proportions of the gold and remanent copper. There are about 300 million mt of material available, and we’re just weeks away from starting a 500-mt trial heap leach there.” MPS is also turning its attention to nickel and cobalt recovery. “We’ve got a very full product development pipeline, strongly supported by our new owners Draslovka who have a vision to introduce solutions that will reimagine the way we supply critical and precious metals to the world,” said Bryan.

“We’ve got a big project underway in Australia with the Future Battery Industries Cooperative Research Center (FBI CRC) which is funded partly by the Australian Government and mining, engineering and supplier companies. We hope to have a viable demonstration ready as part of that in mid-2023. The technology has the potential to be hugely disruptive in the nickel space, particularly for recovery of metal from tailings both freshly produced and legacy tailings left in tailings dams.”

Making Concentration More Sustainable
Advances are also underway in traditional concentration technologies and flowsheets. One of the main challenges is that this pathway is currently very energy and water intensive, and this compounded by the fact that ore grades are declining. If the industry continues to process copper the way it does today, then it’s going to become even more energy and water intensive. Copper production needs to become more sustainable if the zero-emission mine of the future is to be realized.

High-pressure grinding rolls are becoming more widely used in hard-rock applications because they use
significantly less energy than traditional grinding equipment. (Photo: Weir Minerals)

“We’re primarily focused on the movement of materials — for example, with our Warman slurry pumps, GEHO positive displacement pumps and ESCO ground engaging tools — and helping miners reduce their water usage by optimizing their processes,” he said. “In the next 3-5 years, miners will be increasingly focused on reducing energy and consumables by applying alternative technologies that have already been proven in other plants and processes. For example, high-pressure grinding rolls (HPGRs) are becoming more widely used in hard-rock applications because they use significantly less energy than traditional grinding equipment.”

Aside from the focus on reducing carbon emissions, there is also considerable scope to improve tailings and waste management. What form this takes will be site and region- specific but ensuring the safe and sustainable management of tailings is an increasingly important aspect of maintaining a social license to operate. Lempens added that, in the longer term, more disruptive technologies will be required if the mining industry is to realize its net zero targets.

“Weir Minerals currently offers technologies that provide considerable energy and emission reductions, in some cases, over 30% compared with traditional equipment,” he added. “These are all proven technologies and we’re increasingly seeing them being utilized in new and innovative flowsheets to replace traditional technologies. For example, in comminution, the Enduron HPGR combined with air classifiers and/or vertical stirred milling is delivering enormous sustainability benefits. By adding our coarse particle flotation technology to the beneficiation process these benefits can be expanded even further.”

In arid areas where water is a significant operating cost, eliminating the need for gland water for pumps may improve water efficiency, as well as reducing costs. The Warman Hi-Seal pump shaft seal can free up clean water for other critical uses and enhance the project’s social license to operate. Expeller seals also eliminate the need for the extensive infrastructure required to deliver a controlled supply of clean water to dozens of pumps across a mine site.

Warman MCU pumps are also replacing competitor installations in many locations around the world. For example, at Carmen Copper’s Toledo mine in the Philippines, Warman MCU 300 pumps replaced competitor pumps and improved throatbush wear life by 50% and reduced the frequency of full pump rebuilds by up to 350%. These contributed to a 19% increase in equipment availability with the added benefit of decreasing Carmen Copper’s power consumption.

Lempens told E&MJ: “Miners also need to focus on balancing the energy required to recover water from tailings with the broader factors that contribute to sustainable tailings management. The ideal solution will be different depending on the operation and Weir Minerals works with its customers to work through these challenges. We have a range of offerings like Cavex hydrocyclones and TerraFlowing tailings management solutions that deliver sand product gradings for tailings storage facility (TSF) dam wall construction and pumpable dry tailings disposal.”

Weir Minerals’ current developments are focused on moving less rock, using less energy and water, and minimizing waste while also improving operational resilience with digital technologies. “Within these areas, we have identified several stages of technological development,” said Lempens. “For example, we’re developing technologies that reject non-valuable material as early in the process as possible — dry and wet ore-sorting techniques will play an important role in process optimization. Weir Minerals is also focused on harnessing digital technologies to improve mining operations. Our Synertrex digital ecosystem is paving the way for the future ‘connected’ mine and will provide miners with unrivalled visibility of every aspect of their operations.”

The REFLUX Flotation Cell combines several technologies to achieve superior
flotation performance in maximizing recovery, gas flux, bubble liquid segregation
and product cleaning. (Photo: FLSmidth)

“In comminution, with our recent acquisition of TK Mining, FLSmidth has become the market leader in HPGR technology. Our HPGR Pro enables up to 20% more throughput compared to conventional HPGRs, with less energy consumption and up to 30% longer roller life, supporting our clients to succeed on their ESG targets.” ESG issues are a central force in future flowsheet development, not only for copper but for all minerals, and it’s the environmental portion of this trifecta that is influencing innovation, research, and development most heavily. “For all our clients, their main concerns are related to improving efficiency and productivity and using less energy and water while still maintaining or improving concentrate production,” Pelayo added. “Our aim is to produce more metal using fewer resources to keep the industry’s footprint to an absolute minimum.”

There are many areas within copper concentrator flowsheets which offer the potential for improvement. Pelayo believes that preconcentration and innovative comminution technologies offer some of the greatest impacts. “Comminution is where most energy is consumed in minerals processing and 85% of that energy is lost as heat,” he explained. “So understandably, most OEMs are focusing on energy efficiency in this area. There have been a number of technological breakthroughs recently in fields such as microwave assisted comminution and pre-weakening of mineral ores by high-voltage pulsed energy, but there is still long way to go. We need to think big to create a step change in this industry.”

Pelayo added that high environmental standards are also impacting tailings management practices. Miners are particularly keen to assess the feasibility of dry stack solutions. “We offer a complete solution for tailings,” he added. “Including filters, material handling equipment and we have the resources to develop novel concepts, as we did with ECOTAILS.” Going forward, FLSmidth’s biggest R&D focus is on creating ‘the concentrator of the future,’ and the company is working collaboratively with mining companies, universities, governments and other OEMs to advance this concept. It recently announced agreements and partnerships with AVEVA, Microsoft and, most recently, with ABB to accelerate mine digitization.

Pelayo summarized: “We are living through unprecedent times, and market analysts are already predicting a supply gap for copper through 2023-2032. We need to work together to improve efficiency and productivity, not only in new projects but in current operations too. Only through working together will we be successful.”