Tag Archives: SX-EW

Arizona Sonoran Copper hires Ausenco for Cactus and Parks/Salyer project PFS

Arizona Sonoran Copper Company says it has engaged Ausenco as lead engineer to deliver an integrated prefeasibility study (PFS) at the Cactus and Parks/Salyer project, in Arizona, USA, by early 2024.

The project, on private land, is a brownfields site with in-place infrastructure and is accessible via highway.

Additionally, the company is pleased to announce the appointment of Victor Moraila as Chief Engineer, joining as the company transitions into a US-based copper developer.

Ausenco will initially review the Cactus draft PFS and incorporate into the new re-scoped PFS, which includes Parks/Salyer. The study will explore a simple heap leach operation, targeting a potential of 50,000 tons (45,359 t) per annum of LME Grade A Copper Cathode from an on-site solvent extraction/electrowinning (SX/EW) plant.

Mineralised material will be sourced from four deposits initially, including Stockpile, Cactus East, Parks/Salyer and Cactus West.

Pending a successful metallurgical program with Rio Tinto’s Nuton Technologies, and a subsequent commercial agreement, the company and Ausenco will layer in the primary sulphides as a fifth source of mineralised material for the SX-EW plant.

Back in July, Arizona Sonoran announced it had entered into a one-year exclusivity period with Nuton™, a Rio Tinto Venture that, at its core, is a portfolio of proprietary copper leach related technologies and capability. The sulphide potential is not included in the 2021 Cactus preliminary economic assessment, which contemplated a simple heap leach and SX-EW operation over an 18-year mine life, producing an average of 28,000 t/y of LME Grade A copper cathode.

In addition to its own technical staff, Ausenco will lead a technical consultant team comprised of Samuel Engineering, AGP Mining Consultants, Stantec, MineFill Services, Clear Creek Associates and Call & Nicholas Inc.

As part of the PFS work for the project, the company and Ausenco have agreed to complete trade-off and optimisation studies and detailed mine production scenario analysis, in conjunction with AGP Mining, around the following areas:

  • Mineralised material sources from an open-pit expansion (Cactus West), underground development (Cactus East and Parks/Salyer), and the existing stockpile;
  • Ore handling, storage, and agglomeration;
  • Leach pad design and operation;
  • Acid storage, consumption and handling;
  • Solvent extraction and electro-winning;
  • Existing and new infrastructure (as required);
  • Preliminary design of access roads in coordination with mine access roads;
  • Preliminary design and location of mine support facilities; and
  • Mine and geotechnical design.

A PFS detailing the oxide and enriched mineralised material is projected to take approximately 10 months to complete, with results currently expected in the December quarter of 2023. Based on the results of current metallurgical testing with Nuton, layering in the primary sulphide material into the mine plan would extend delivery into early 2024.

George Ogilvie, ASCU President and CEO, said: “As Arizona Sonoran Copper Company emerges as a mid-tier copper developer, we are thrilled to welcome the depth of experiences of both Victor and Ausenco; each rooted in quality and value-driven projects. Looking forward, Arizona Sonoran Copper Company is bolstering the technical services team, necessary team to deliver domestically produced copper into the US copper supply chain, from the third largest independent copper deposit in the US.”

Freeport furthers its leading copper leaching excellence

Among the new applications, technologies and data analytics Freeport-McMoRan is advancing as part of a plan to improve copper recovery from its leach processes in North and South America is Jetti Resources’ patented catalytic technology, the company has confirmed to IM.

In its December quarter and 2022 annual results, released late last month, the leading copper miner said it believed the leach innovation initiatives it was pursuing provided potential opportunities to produce incremental copper from its large existing leach stockpiles and lower-grade material currently classified as waste.

The company has been exploring the potential for incremental low-cost additions to its production and reserve profile for some time, saying in the latest results release that it had identified opportunities to achieve an annual run rate of 200 MIb/y (90,718 t/y) of copper through these initiatives by the end of 2023.

Freeport has a long history of copper leaching production with its Americas division, which includes assets such as Morenci and Cerro Verde, having developed and implemented industry-leading technologies for leaching of oxide ores.

The company has been pursuing internal and external initiatives to expand this leading position, focusing on traditional ores and sulphide orebodies that have been typically considered difficult to leach, like chalcopyrite.

This is where Jetti’s technology comes in.

The Colorado-based company has developed catalytic technology to allow for the efficient and effective heap and stockpile leach extraction of copper. This bolts onto existing solvent extraction/electrowinning (SX/EW) leaching plants so it can be deployed rapidly with limited capital expenditure and, because it uses no heating or grinding, has low operational costs. In addition, there are huge environmental benefits from using leaching over pyrometallurgy, according to Jetti.

A Freeport spokesperson confirmed to IM that the company was in a trial of the Jetti technology through “a commercial installation” at its Bagdad mine in Arizona, USA. This mine is one of its major leaching test hubs, with the company targeting over 3 MIb/y of incremental copper cathode production from the open-pit copper mine through this work.

Bagdad has a 77,100 t/d concentrator that produces copper and molybdenum concentrate, an SX/EW plant that can produce approximately 6 MIb/y of copper cathode from solution generated by low-grade stockpile leaching, and a pressure-leach plant to process molybdenum concentrate.

The spokesperson added: “There is potential to expand production via the treatment of additional stockpiles at Bagdad in the future based on results.”

The use of Jetti’s technology is one of several leaching initiatives the company is pursuing – some with outside vendors, some using its own technology and some with joint venture partners.

All of these are focused on not only adding low-cost production to Freeport’s large production base, but also achieving a lower carbon footprint.

Jetti, which Freeport is an investor in, has been conducting a carbon footprint study and Life Cycle Assessment (LCA) of its technology, with the LCA including analyses of typical copper mining operations without Jetti’s technology and a mining operation with Jetti’s technology installed. The LCA is being conducted in conformance with the ISO 14040/44 standard and will be critically reviewed by an independent expert.

Jetti Resources has developed catalytic technology to allow for the efficient and effective heap and stockpile leach extraction of copper

Jetti has also committed to starting to track water usage and waste at all its operations and sites, which includes the installation it has at Capstone Copper’s Pinto Valley operation, also in Arizona.

At Capstone’s operation, Jetti technology is being used extensively as part of a plan to recover up to 350 MIb of cathode copper over the next two decades from historic and new mineralised waste piles.

Teck Resources has also taken an interest in Jetti’s technology having signed an agreement for the evaluation of the solution at a number of Teck’s assets with potential copper resources outside of existing mine plans. BHP, through its BHP Ventures arm, is also an investor in Jetti.

As to Freeport’s wider leaching plans, it said it was looking to use data analytics to provide new insights to drive additional value, while new applications to retain the heat in the stockpiles were “yielding results”.

The company has assessed that it has some 38,000 MIb of contained copper in leach stockpiles deemed “unrecoverable” by traditional leach methods. Of this amount, about 50% is from the massive Morenci mine, which already has leaching production capacity of 900 MIb/y of copper.

Asiamet engages BGRIMM for SX-EW plant engineering and procurement work at BKM

Asiamet Resources Limited says it has signed a Memorandum of Understanding (MoU) with BGRIMM Technology Group (BGRIMM) in relation to the engineering and procurement of the solvent extraction and electrowinning (SX-EW) plant for the BKM copper project processing facility in Indonesia.

BGRIMM is a leading Chinese engineering, procurement and construction (EPC) group providing services to the mining industry worldwide.

The MoU will see the two companies, alongside Asiamet’s consulting engineer, NewPro Consulting & Engineering Services Pty Ltd, work on the detailed design information for all equipment packages that BGRIMM has provided cost estimates for as part of the current BKM copper project feasibility study update.

BGRIMM will also complete a detailed cost estimate for an EPC Technical Supervision scope of work for the project’s SX-EW processing plant, which will be used in the FS update capital cost estimate. Upon successful completion of this update and a positive final investment decision by the Asiamet Board, the company will engage with BGRIMM on the provision of a complete engineering and procurement service contract for the SX-EW plant. This will include the supply of all necessary equipment for the SX-EW plant and coordination with suppliers of materials from within Indonesia.

Asiamet will also work with BGRIMM to develop the technical construction supervision requirements for the SX-EW plant when moving into the execution phase as well as commissioning services as required.

The SX-EW plant is a critical component of the BKM processing facility as it delivers the processes of metal purification and copper metal production, Asiamet said. It can be considered a discrete facility with well-defined battery limits, therefore is suitable for delivering as an engineering and procurement package.

Darryn McClelland, Asiamet CEO, added: “BGRIMM have already assisted our engineering consultants NewPro with various equipment pricing used in the FS update capital expenditure estimate as well as costs for executing the engineering and procurement services necessary for delivery of the SX-EW plant.

“Capital cost is a critical component of the feasibility of the BKM copper project and working with BGRIMM is one of a number of opportunities we have taken to help control cost and mitigate the inflationary backdrop seen in 2022. BGRIMM have a strong track record of delivering cost effective engineering and designs for SX-EW plants of the size we are proposing for the BKM copper project and we are very keen to tap into this experience. Asiamet looks forward to developing a strong working relationship with BGRIMM through involvement in the development of the BKM copper project, along with future development opportunities that are likely to arise from the broader KSK Contract of Work.

“Final discrete elements for the delivery of the updated Feasibility Study are nearing completion and we look forward to delivering on this in the near term and critically presenting a project with overall robust economics and attractive cashflow generation.”

A 2022 feasibility study on BKM outlined a maximum 4.5 Mt/y treatment rate from a nine-year heap leach SX-EW operation.

Antofagasta readies primary sulphide leaching technology options

The ability to leach primary copper sulphides has, on many occasions, proved a hurdle too much, with conceptual work in the laboratory or pilot scale falling down on sub-economic or volatile recovery rates when working out in the field.

This problem tends to result in one of two things: new capital-intensive concentrators are brought into process these sulphides, or brownfield oxide operations are drafted up that prolong existing leaching operations for a few more years when – hopefully – copper prices are higher.

Antofagasta has come up with an alternative option that leverages chloride-based reagents and 20-years of knowledge leaching secondary sulphides.

Called Cuprochlor®-T, the proprietary process has undergone five years of intense development leading to the point that the company is now open to talking about its potential.

It leverages off the first iteration of leaching technology Antofagasta devised for secondary sulphides – Cuprochlor.

Cuprochlor, which is now working at the Michilla mine in Chile (which Antofagasta sold in 2016), effectively binds together the particles of mineral – particularly fine in the case of Michilla – into a porous but manageable material that can then be heap leached. The agglomeration is achieved by mixing the mineral and leach solution with chloride salts and sulphuric acid, which react to form a plaster-like paste.

Over the years, the process has been refined, going on to consistently deliver recovery rates of around 90%.

Sitting on an expansive base of primary sulphide resources – mainly chalcopyrite – and the success of Cuprochlor, Antofagasta, around five years ago, began a series of tests, adjusting variables such as temperature, reagent concentrations and particle size to see if the chloride leaching process could be adapted for the treatment of primary sulphides.

Temperature proved to be one of the keys, with tests showing that by elevating the temperature of the heap to around 30°C, Cuprochlor-T was able to stimulate the required chemical reaction for recovering copper from primary sulphides such as chalcopyrite.

Another key differentiator between the two chloride leaching technologies is the “reagent recipe” and particle size distribution (PSD), Alan Muchnik, VP Strategy & Innovation for Antofagasta, told IM.

“Providing a constant temperature throughout the process is very important, but the real innovation is the approach we have used,” he said. “It involves a combination of factors, including, among others, the recipe for reagent concentrations and the required PSD.”

While not wanting to reveal the ‘secret sauce’, Muchnik said the PSD consideration goes beyond the usual P80 industry reference point.

It is this balance that has landed the company with recoveries of over 70% after approximately 200 days of leaching on the heap in test work.

Muchnik expanded on this: “The Cuprochlor-T process, in simple terms, involves leaching in a chloride environment – where there are no passivation layer bonds. This allows for the copper, iron and chloride ions to react, which, at a controlled temperature, results in the economic production of copper.”

This is through three stages:

  • First up is an agglomeration stage where the necessary reagents are added and are left to rest at a constant aeration and temperature;
  • Second, the ore is irrigated intermittently with continued aeration, also maintained at a constant temperature; and
  • Finally, after 200 days, the ore completes the leaching cycle and allows the company to obtain recoveries of 70% copper or more.

What started with laboratory testing and progressed to pilot testing and a “semi-industrial” test on several different heaps at Centinela has recently concluded with an industrial test of over 40,000 t of primary sulphide material averaging 0.4% Cu – containing more than 90% chalcopyrite – that, using the same process outlined by Muchnik, showed consistent recoveries of over 70%, he said.

Alan Muchnik, VP Strategy & Innovation for Antofagasta

Asked if the company is eyeing even higher recoveries that can compete with the levels Cuprochlor is achieving on secondary sulphides, Muchnik said it was all about an economic tradeoff.

“It may be possible to hit such a percentage [as Cuprochlor], but that is not the aim or expectation with the kinetics we are currently seeing in Cuprochlor-T,” he said. “There is always a tradeoff between the length of irrigation time, the PSD and the recoveries, all of which are related to capital costs, operating costs and the payback associated with the process.”

The Antofagasta planning and operations teams have now got their hands on the Cuprochlor-T ‘licence’ and will be busy outlining potential deployments for consideration in the company’s annual planning cycles.

There are some obvious places to start.

The Zaldívar open-pit, heap-leach copper mine, 175 km southeast of Antofagasta, is currently in the process of transitioning to chloride leaching operations with Cuprochlor.

The project, which includes an upgrade of the SX plant and the construction of new reagent facilities and additional washing ponds for controlling chlorine levels, was completed in January 2022 and is now being commissioned. It is set to boost copper recoveries by approximately 10 percentage points, increasing production at Zaldívar by around 10,000–15,000 t/y over the remaining life of mine.

“In addition to transitioning to chloride leaching with Cuprochlor for secondary sulphides, we are currently progressing studies for the primary sulphide orebody that currently lies below the Zaldívar reserves to prove if Cuprochlor-T leaching can work,” Muchnik said. “Within our resource base, there are approximately 460 Mt of primary sulphide resources declared here.”

Both Centinela and Antucoya have primary sulphide resources and existing heap leach and SX-EW facilities that would fit the Cuprochlor-T blueprint too.

Muchnik said: “One of the technology attractions of Cuprochlor-T is the ability to use otherwise idle leach pad and SX-EW capacity. That it is the scale limitation at our current operations, but the technology can be gradually deployed within a plant that is already adapted for chloride leaching, phasing this in during the life of mine to fit requirements.

“It provides an ongoing adoption process option rather than an immediate infrastructure project that sees an operation shift from oxide leaching to a different kind of heap leaching in one go.”

The advent of Cuprochlor-T does not mean the company will completely drop potential concentration projects, Muchnik clarified, highlighting the second concentrator project currently subject to a feasibility study at Centinela.

In addition to the capital and operating cost benefits that would come with Cuprochlor-T over the concentration route, there is likely to be a sustainability benefit.

“It’s only an indicative reference as each case is different, but you would expect the energy consumption associated with Cuprochlor-T leaching and SX-EW treatment to be less than half of the normal route of copper concentration and SX-EW,” Muchnik said.

In this respect, it is a favourable consideration for Antofagasta’s long-term carbon-neutral goals.

While each potential Cuprochlor-T implementation will have to go through corresponding project studies, Muchnik was confident in predicting that new copper from Cuprochlor-T would be produced this decade.

With five years of substantial testing under its belt, not many metallurgists would bet against him.

Atalaya Mining approves construction of E-LIX-backed processing plant at Riotinto

Atalaya Mining has, following a feasibility study, approved the construction of the first phase of an industrial-scale plant using the E-LIX System to produce high value copper and zinc metals from the complex sulphide concentrates sourced from Proyecto Riotinto (pictured) in Spain.

Following its announcement on October 28, 2020, Atalaya concluded the study, which evaluated the technical and economic viability of producing cathodes from complex sulphide concentrates by applying E-LIX, a new, patented electrochemical extraction process developed and owned by Lain Technologies Ltd.

Relative to conventional flotation techniques, the value creation potential of E-LIX offers a unique opportunity for Atalaya, it said. As a result – and as previously disclosed – the company secured certain terms of exclusivity with Lain Tech for the use of E-LIX within the Iberian Pyrite Belt.

The E-LIX plant will dissolve the valuable metals contained within the concentrates. The test work and system design allows for the dissolution of chalcopyrite while avoiding the passivation of particles. After copper or other metals are brought into solution, they can be recovered by conventional precipitation or solvent extraction followed by electrowinning (SX-EW).

Phase I plant capacity has been designed to produce between 3,000-10,000 t of copper or zinc metal per year depending on the ratio of copper to zinc in the concentrate feed.

The estimated capex for Phase I is €12 million ($13.6 million) and the design allows for unlimited capacity expansion through the addition of multiple lines in parallel. Atalaya will start the construction of the plant in the coming weeks and it is expected to be operational in 2022, including commissioning.

The decision to approve and construct the Phase I industrial-sized plant follows over six years of evaluation and de-risking work including continuous tests at the laboratory, a small pilot plant and finally a semi-industrial pilot plant, Atalaya explained.

A semi-industrial E-LIX pilot plant was constructed in late 2019 and has operated during 2020 and 2021, despite the challenges of the COVID-19 outbreak. The results of the pilot tests were included in the feasibility study and successive optimisation work. The long run continuous tests demonstrated the feasibility of leaching complex polymetallic concentrates with global recoveries of over 95% for copper and zinc while producing clean metal precipitates and/or high purity metals.

Atalaya said the use of the E-LIX System has shown the potential to unlock the significant value from the polymetallic sulphides contained within Atalaya’s mineral resources, including:

  • The polymetallic deposits of San Dionisio, San Antonio, Masa Valverde and Majadales, all of which are located in the Iberian Pyrite Belt and within trucking distance of Proyecto Riotinto’s  15 Mt/y processing facility;
  • The significant contained metal within these historical drilled resources from San Dionisio and Masa Valverde contain over 1.1 Mt of copper, 2.4 Mt of zinc, 1.7 Moz of gold, over 110 Moz of silver as well as additional lead resources. These figures are in addition to the over 1 Mt of copper reserve at Proyecto Riotinto’s Cerro Colorado orebody and at Proyecto Touro; and
  • Historical applications of differential flotation within the Iberian Pyrite Belt in Spain and Portugal have typically resulted in recoveries of 60-80% into concentrates for complex copper-zinc polymetallic sulphides, with even lower recoveries historically reported for lead, silver and gold. The use of hydrometallurgical systems, such as E-LIX, has demonstrated that base metal recoveries of over 90% can be achieved.

E-LIX is, Atalaya said, also expected to reduce Atalaya’s carbon footprint. By producing high-purity metals on-site, Atalaya can reduce the transportation costs associated with delivering concentrates to smelters, avoid treatment and refining charges associated with converting concentrates into metal and eliminate penalties associated with deleterious elements often contained within concentrates produced in the Iberian Pyrite Belt and elsewhere. The E-LIX plant is also expected to use the renewable energy that will be produced by Proyecto Riotinto’s planned solar plant.

Alberto Lavandeira, Atalaya CEO, said: “The E-LIX System offers Atalaya a unique opportunity to unlock significant value from its portfolio of deposits that contain complex polymetallic mineralisation. Atalaya has worked together with Lain Technologies for many years in order to test, refine and demonstrate the E-LIX process, providing the company with confidence in its potential. In addition to enhancing recoveries, E-LIX will eliminate penalties associated with deleterious elements and reduce the costs of transportation and energy, thereby improving the company’s carbon footprint.”

Lifezone hydromet tech blueprint puts Kabanga Nickel in pole refining position

Kabanga Nickel is ready to put its ‘money where its technology is’ in the pursuit of production from a highly prospective nickel-copper-cobalt asset in Tanzania, according to Keith Liddell, Executive Chairman.

Having been granted access to a project that has had more than $290 million spent on it by previous owners such as Barrick Gold and Glencore between 2005 and 2014, including 587,000 m of drilling, the company is coming at the Kabanga project with a fresh set of eyes and a plan that aligns with the government’s in-country beneficiation requirements.

The outcome of this previous investment is an in-situ mineral resource of 58 Mt at 2.62% Ni, containing more than 1.52 Mt of nickel, 190,000 t of copper and 120,000 t of cobalt. This resource is in the process of being updated with the latest modelling software.

The Barrick-Glencore joint venture also outlined a mine plan in a draft feasibility study that looked to recover 49.3 Mt of ore at 2.69% nickel equivalent from the two primary orebodies – North and Tembo. Again, Kabanga is re-evaluating this strategy, having identified several opportunities to enhance project outcomes including a development plan that facilitates higher production rates and access to high-grade ore earlier in the mining schedule.

Yet, the biggest departure from the previous plans for Kabanga is the “mine to metal” concept that Liddell and Dr Mike Adams, Senior Vice President: Processing & Refining, have been marketing.

This is part of the reason why the Tanzanian Government signed a binding framework agreement with Kabanga Nickel earlier this year that resulted in a joint venture company called Tembo Nickel Corp (owned 84% by Kabanga Nickel and 16% by the Government of Tanzania) to undertake mining, processing and refining to Class 1 nickel with cobalt and copper co-products near the asset.

Unlike the plethora of smelter plans being drawn up in the likes of Indonesia and the Philippines – two other countries attempting to keep more ‘metal value’ in-country – Kabanga’s plan hinges on a hydrometallurgical refining route.

This isn’t a carbon copy of the high pressure acid leaching (HPAL) technology the industry is used to hearing about – most of the time for the wrong reasons. The hydrometallurgy Kabanga is talking about is more in keeping with the process Vale uses at Long Harbour in Canada, Adams pointed out.

“There’s hydrometallurgy and then there’s hydrometallurgy,” he told IM. “HPAL is incredibly different to the Lifezone hydrometallurgy we are proposing at Kabanga, which is dealing with sulphide concentrates. Our process is effectively 17% of the HPAL carbon footprint; HPAL has a much higher carbon footprint than smelting, let alone what we are proposing.

“Our technology comes with lower temperatures and pressures, and the materials of construction are nowhere near as exotic as HPAL. It is more economic and more environmentally friendly than both HPAL and smelting.”

The ‘Lifezone’ Adams mentioned is Lifezone Limited, a technology and development company established by Liddell to exclusively own and develop the patented rights to the Kell Process – a unique hydrometallurgical process. Although devised to treat platinum group metals and refractory gold ores without smelting or the use of cyanide, and with major energy savings, cost benefits and a significantly reduced environmental impact (CO2 and SO2) over conventional technologies, the Kabanga team is keen to draw from Lifezone’s experiences when it comes to devising the refining plan in Tanzania.

They and much of the South African platinum industry are looking at developments at Sedibelo Platinum’s Pilanesberg Platinum Mines (PPM) operation on the Bushveld Complex where a 110,000 t/y beneficiation plant employing the Kell Process is currently being constructed. This plant has the capacity to produce 320,000 oz/y of platinum group metals at the refinery end, with seven refined metal products set to be produced on site.

If Sedibelo, which Liddell is a shareholder of, can achieve such a feat, it will become the first South African PGM operation producing refined PGM, gold and base metal products on site. At the same time, this metal production would come with some 82% less energy consumption and the associated significant reduction in carbon emissions, plus improved recoveries and lower operating costs, than conventional off-site PGM smelting.

But, back to Tanzania, where the aim is to deploy hydromet technology with a specifically designed flowsheet to leach and refine the base metals. End products from the Kabanga refinery will be Class 1 nickel and cobalt metals with >99.95% purity readily saleable to customers worldwide, as well as A-grade copper cathode for the Tanzanian market, according to the company.

Not only is this different to conventional pyrometallurgical nickel sulphide smelting and refining – which, according to Liddell comes with around 13 t of CO2 emissions per tonne of Class 1 nickel metal, compared with the 4 t of CO2 emissions per tonne of nickel (Nickel Institute industry baseline numbers) with the Lifezone hydrometallurgical route – it also removes the need to transport and export concentrate long distances to European, North American or Asian smelters and refineries for further processing.

Such benefits and plans go some way to answering the questions around how Kabanga is holding a nickel-copper-cobalt asset that many battery metal investors and mining companies would be interested in.

Kabanga Nickel is putting Lifezone’s hydrometallurgy expertise to the test at the project in Tanzania

The majors might not be ready to offer up a plan featuring in-country beneficiation with new technology, but Kabanga and Lifezone are.

“As you know, the industry is very conservative – no-one wants to be first, they want to be second,” Liddell said. “As technology providers, we’re going to be first and second – first with the Kell Process plant in South Africa and second with the hydromet plant at Kabanga.

“We have ownership in those so, in effect, we are putting our money where our technology is. In a conservative industry, you have to do this.”

Liddell is right.

Take battery-electric vehicles or hard-rock cutting technology on the mobile equipment side of the mining business. The OEMs, to gain market traction, had to invest in the technology, build prototypes and mine-ready vehicles and then convince the miners to test them at their sites – most of the risk was held with the tech providers, not the miners.

While Lifezone will have to take on similar technology and financial risks for industry buy-in, all the billed benefits of its hydromet technology fit the mining industry ESG and productivity brief, making it a technology that has applications beyond Kabanga, Tanzania and nickel.

According to the company, it represents an architecture of several well-proven “breakthrough” hydromet process technologies – namely pressure oxidation of sulphide minerals, selective solvent extraction of metals and selective metal absorbents – that realise the value of all waste streams, both in-process and by constructing local, regional and global circular economies.

It comes with higher metal recoveries, lower costs, lower environmental impact, a less complex flowsheet, shorter production pipeline and reduced value lockup for those companies employing it. This means metal production comes sooner, more metal is produced at a lower cost and with a lower footprint and less potentially payable metal is left in the waste stream due to a lack of viable processing options.

The main unit operations at Kabanga are likely to include aqueous pressure oxidation in an autoclave to dissolve the sulphides and remove the base metals; copper refining by SX-EW; iron removal to purify the solution for cobalt and nickel refining; cobalt refining by SX-EW; and nickel refining by SX-EW. This could result in 40,000-50,000 t/y of nickel metal as cathode, powder or briquette, alongside 8,000 t of copper cathode and 3,500 t/y of cobalt cathode or rounds.

The refinery blueprint – designed in a modular manner to bolt on additional process trains, according to Liddell and Adams – could see Tanzania become the multi-metals processing hub it has eyes on, processing material from across East Africa and retaining more value in-country. Down the line, it could align itself even closer with the battery metals sector by producing precursor products that gigafactories are calling out for.

Beyond Kabanga Nickel, Liddell sees potential for applying this hydromet concept at existing smelting operations to lower the footprint and operating cost of operations.

“The hydromet process uses anywhere between one fifth and one third of a smelter’s electricity input,” he explained. “You can replace a 50 MW electric smelter with a 10 MW hydromet plant. At the same time, the process allows refiners to get more metal out of the concentrate. This means the lower energy draw and increased revenues can pay back the money invested in a hydromet plant.”

For operations looking to incorporate more renewables, this reduced power draw is a major selling point.

Similarly, for countries like South Africa looking to retain or grow its metal production blueprint while weaning themselves off coal amid routine power blackouts, the concept stacks up.

“In South Africa, you could end up producing the same amount of metals off a much lower power base, and it’s then much cheaper to green up that electricity,” Liddell said.

The potential is vast, and Kabanga Nickel has an 18-month program currently ahead of it to start development.

This one-and-a-half-year plan follows the recent issue of a mining licence that allows the company to get on the ground – symbolised by the drill rig (pictured above) that is about to start turning on site.

Over this timeframe, the plan is to update the existing feasibility study numbers and bolt a refinery module onto it, explore avenues with metallurgical drilling to boost the concentrate grade and re-work the mine design to access the two orebodies simultaneously. The latter is one of the ways the team could access more value sooner in the production process.

All of this could set the company up to start production from Kabanga in 2024-2025, 1-2 years after the Kell Process goes live at Sedibelo’s operation and in time for a further run up in battery metals demand and, most likely, more governments legislating for in-country beneficiation.

Kabanga Nickel and Lifezone’s plans could end up being a future tried-and-tested blueprint.

Metso Outotec VSFX solvent extraction tech set for Taseko’s Florence Copper Project

Metso Outotec has signed an agreement with Florence Copper Inc, a subsidiary of Taseko Mines Ltd, to supply copper solvent extraction and electrowinning technology for a plant to be built in Arizona, USA.

The order, exceeding €20 million ($24 million), has been booked in the Metals’ segment September quarter orders received.

The Metso Outotec delivery includes the modular VSF®X solvent extraction plant and the main process equipment for the electrowinning plant.

“We are very excited to have purchased the key SX/EW process equipment from Metso Outotec, a world leader in mineral processing and hydrometallurgical technologies,” Stuart McDonald, President and CEO of Taseko Mines, says. “The VSFX technology is ideally suited for our Florence Copper Project, which is set to become one of the most energy-efficient and low-carbon copper producers in the world. The modular nature of the equipment will reduce construction time and allow Florence to commence copper production quicker than with other technologies available.”

Back in February, Taseko, having just completed a $400 million bond refinancing and fundraising program, said it was moving forward with developing a commercial operation at its Florence in-situ recovery project.

Jari Ålgars, President of the Metals business area at Metso Outotec, says: “We are looking forward to working with Taseko Mines on the Florence Copper Project. The energy-efficient VSFX solvent extraction plant, which is part of our Planet Positive product range, reduces emissions and is safe to operate. The Florence Copper Project will become an important new reference for Metso Outotec in the US copper market as a supplier of a complete production plant that uses solvent extraction and electrowinning technology for copper recovery.”

Trevali to test out FLSmidth’s Rapid Oxidative Leach tech on Caribou material

Trevali Mining has announced the commencement of a pilot plant testing program using Caribou run-of-mine and milled material at FLSmidth’s Rapid Oxidative Leach (ROL) process testing facility in Salt Lake City, Utah.

The program expands on previous laboratory test work and is aimed at demonstrating the potential to recover zinc, lead, copper, gold and silver as a precipitate or metal and additional zinc and lead from Caribou ore and mill tailings.

The leach test program is targeting an improvement to zinc, lead, copper, gold and silver metal recoveries, the potential to produce a precipitate or metal on site replacing the current ore concentrate that is produced at Caribou – which, if implemented, would lead to savings on transport costs and offsite treatment costs – and the opportunity to process historic mill tailings, which include gold and copper metals, in addition to run of mine ore. The latter would increase revenues and reduce closure liabilities, Trevali said.

Trevali says the use of FLSmidth’s ROL technology also provides the potential to reduce Trevali’s carbon footprint at Caribou and extend Caribou’s mine life and treat lower-grade deposits in the Bathurst camp of Canada.

FLSmidth says ROL leaches 97-99% of copper directly on-site in six to eight hours, from concentrates as low as 5% Cu. In gold, ROL has the potential to unlock the value of undeveloped refractory gold deposits with less than 3 g/t gold head grade, it says.

Unlike other refractory processing techniques, the ROL process uses the application of mechanical energy coupled with oxidation under atmospheric conditions. The process relies on stirred media reactors to accelerate the oxidation of sulphide minerals. This eliminates the need for ultrafine grinding, high temperatures and high pressure which makes it energy saving and very cost-effective, according to the mining OEM.

Trevali said a successful pilot plant test program using ROL may allow Trevali to replace the existing flotation circuit at Caribou with atmospheric leach vessels and potentially an SX/EW train, introducing the possibility of producing base and precious metals on-site and thereby save transport costs and offsite treatment costs.

Conceptual objectives of the program include:

  • Recovery of metals/minerals that are not recoverable using the current technology at Caribou (precious metals and magnetite); and
  • Improved payables/selectivity of the traditional flotation process using new and emerging technologies.

Ricus Grimbeek, President and Chief Executive Officer of Trevali, said: “FLSmidth’s ROL metallurgical technology has the potential to transform the Caribou mine and the wider Bathurst Mining Camp.

“This next phase of the testing program is an essential step in evaluating the suitability and economic viability of a processing solution with the potential to enhance the value of the in-situ material and tailings at Caribou as well as the surrounding deposits in the Bathurst region. The positive results to date support further study and analysis given the potential implications for the Bathurst Mining Camp in general and Trevali in particular.”

Beyond quantifying the ability to recover additional metal values, the objective for the pilot plant test program is to determine the various kinetic factors, mass and energy balance and engineering data to support future engineering on a preliminary economic assessment for potential processing of the Trevali mill feed and mill tailings and produce metal on site.

Continuous pilot plant trials commenced in June 2021 (Phase 1) to tune the pilot plant and provide material for precious metal leach tests in late July, followed by a test program at the Caribou Mine site that is planned for September 2021 (Phase 2). Leach data and results are expected to verify that batch testing results can be achieved in a continuous operation.

Atalaya Mining evaluating Lain Tech’s E-LIX System for copper cathode production

Atalaya Mining has commenced the execution of a feasibility study to evaluate the economic viability of producing cathodes from complex sulphide ores prevalent in the Iberian Pyrite Belt through the application of a new extraction process called the E-LIX System.

The production of cathodes has the potential to generate cost savings by reducing charges associated with concentrate transportation, treatment and refining, and penalty elements, while also reducing carbon emissions, the company said.

E-LIX System is a newly developed electrochemical extraction process developed and owned by Lain Technologies Ltd, led by Dr Eva Lain, who holds a PhD in Electrochemistry research from the University of Cambridge.

Through the application of singular catalysts and physico-chemical conditions, E-LIX System is able to achieve high metal recoveries under low residence times, by accomplishing rapid reaction rates while overcoming classic surface passivation issues that have typically impaired metal recovery from complex sulphide ores, Atalaya said. E-LIX System is considered to be a more environmentally-friendly process than existing technologies; it generates zero emissions and does not consume water or acid, and runs under mild operating conditions (atmospheric pressure and room temperature).

Patented in 2014 by Lain Tech, the E-LIX System has been developed in collaboration with Atalaya from an initial concept in the laboratory to a fully operational pilot plant located at Proyecto Riotinto, in Spain.

The pilot plant with a capacity of 5 t/d has been running for the past nine months, with only mandatory stoppage owing to COVID-19 restrictions. Leach rates of up to 250 kg/h have been achieved processing copper concentrates, zinc concentrates and blends of different types of sulphides, according to the company. The pilot plant also contains a solvent extraction and electrowinning (SX-EW) section and has successfully produced high purity copper cathodes as a proof of concept.

Excellent leach results with recovery rates well over 90% have been attained, the company said. Fast kinetics for copper and zinc have also been successfully achieved overcoming the well-known passivation problem of leaching primary sulphides.

The pilot plant has demonstrated that the E-LIX System effectively treats the impurity levels typically associated with the complex sulphides present in the pyrite belt that runs through the south of Portugal and Spain and prevalent at Proyecto Riotinto.

During the past five years, Atalaya has provided financial assistance to Lain Tech to develop the E-LIX System and has now reached an agreement with Lain Tech to use its patents, on an exclusive licence basis within the Iberian pyrite belt in Spain and Portugal.

Under the terms of the licence agreement and based on the encouraging operating results at the pilot plant, the company has commissioned a feasibility study to evaluate the construction of an industrial scale plant for the production of a minimum of 10,000 t/y of copper cathode metal. The study at a cost of around €1 million ($1.2 million) will be funded by Atalaya and is expected to be finalised in 2021. The agreement also provides for a profit sharing arrangement between Atalaya and Lain Tech.

“The feasibility study will be based on the results obtained from the pilot plant and aims to confirm the scalability of the E-LIX System and the capital and operating costs of the industrial plant,” Atalaya said. “Should the industrial plant be built, it will be funded and constructed by Atalaya with Lain Tech designing, operating and managing the E-LIX System.”

Atalaya believes that the use of the E-LIX System could potentially be applicable to the large amount of complex sulphide ore inventory present throughout the Iberian pyrite belt, including Atalaya’s mining properties such as Proyecto Riotinto and Proyecto Masa Valverde, it said.

Atalaya CEO, Alberto Lavandeira, said: “We are fortunate to have been given this unique opportunity to work with Dr Eva Lain in the development of the E-LIX System. I believe this system has the potential to play an important role in the economic treatment of many complex orebodies worldwide. We look forward to updating the market on the results of the feasibility study.”

CAML’s Kounrad operation hits copper cathode milestone

Central Asia Metals Ltd (CAML) says, on April 18, the Kounrad copper recovery plant, in Kazakhstan, produced its 100,000th tonne of cathode – a significant milestone for an operation processing material previously deemed as ‘waste’.

CAML’s Kounrad copper resources are within the waste dumps formed during prior mining activities of the Kounrad deposit, which commenced in the 1930s.

The facility recovers copper from the Eastern and Western dumps that accumulated from open-pit mining operations from a period that started in 1936 and ended in 2005. Over time, oxides and low-grade sulphides of copper formed a significant tonnage deposited at the mine site.

Leached metal from the dumps finds its way to the solvent extraction and electrowinning processing plant via a series of storage ponds. At the plant, copper is produced with the final cathode product delivered from the Kounrad site by rail and sea to the end customers, predominantly in Turkey.

Since CAML’s leaching operations began in April 2012, Kounrad has produced 100,000 t of copper cathode at C1 cash costs averaging $0.55/Ib, or $1,212.54/t (2012-2019); has generated gross revenue of $601 million from copper sales (2012-2019); and has supported a Kazakh workforce comprising 323 employees and 86 contractors (2019).

Nigel Robinson, Chief Executive Officer, said: “We are delighted to have reached this significant milestone of producing 100,000 t of copper from Kounrad at costs that are amongst the lowest in the world. We owe a debt of gratitude to the on-site team led by General Director, Pavel Semenchenko, and guided by our Technical Director, Howard Nicholson.”