Tag Archives: tailings

Draslovka to bring glycine leaching expertise to OZ Minerals TAD incubator

Draslovka Holding a.s., a Czech family-owned global leader in cyanide-based specialty chemicals, says its glycine leaching technology has been selected to be part of the OZ Minerals’ Think & Act Differently (TAD) incubator and Waste-to-Value Challenge.

The latter challenge, announced back in December, sees Rio Tinto and Boliden working in collaboration with OZ Minerals to eliminate, minimise, reuse or find new value in mine tailings and ultimately reduce the global carbon footprint of the mining industry. Draslovka said: “The Waste-to-Value Challenge aims to unlock innovative technologies for managing tailings, helping the mining industry to reduce risk while extracting more of the materials the world needs from what was previously regarded as waste for the energy transition at large. Benefits that the initiative hopes to deliver include lower emissions and reduced waste.”

Draslovka offers a range of sustainable solutions to the global mining industry, and its glycine leaching technology (branded as its GlyLeach™ and GlyCat™ processes) represents the best environmentally-friendly alternative to traditional acid and cyanide leaching, according to the company. Due to its selectivity over gangue minerals and the recyclability of glycine, its use enables the recovery of both base and precious metals from lower-grade resources like tailings. This leads to a more sustainable production process and improved economics that are desperately needed to close the looming critical metal supply deficit.

Ivor Bryan, Draslovka’s Mining Innovation Director, said: “I am proud that Draslovka has been invited to participate in the Waste-to-Value Challenge with forward looking companies that understand the need to reimagine solutions for the mining industry. This aligns with our ambition to become the leading supplier for innovative and sustainable solutions for the wider mining industry.”

Speaking to IM on the sidelines of the recent Resourcing Tomorrow conference, in London, Bryan said the company was embarking on around 10 projects in the mining space, which will prove up the 3,500 hours of testing that has been conducted at MPS’ facilities in Perth, Western Australia.

Anglo American ushering in a new era of tailings disposal with Hydraulic Dewatered Stacking tech

While the El Soldado copper operation in Chile may be one of Anglo American’s smaller assets, it has a big part to play as one of the company’s FutureSmart Mining™ hubs, piloting some of its innovative mining and processing technologies, according to Phil Newman, Anglo American’s Head of Innovation.

Including in this innovative technology bracket is Anglo American’s patented Hydraulic Dewatered Stacking (HDS) technology.

Newman explained: “Mineral processing operations commonly use large amounts of water for the recovery of valuable minerals. This ultimately results in the production of large volumes of wet tailings which are disposed in conventional tailings storage facilities. If not safely constructed and maintained, they pose a major risk to communities and the environment. Eliminating these facilities is a key objective for a safe and sustainable mining industry.”

With 75% of Anglo American’s assets globally located in water-constrained areas, the company must reduce its dependence on water and it is working on technologies to help it achieve closed loop operations with respect to water, according to Newman. HDS is a key enabler of its FutureSmart Mining innovation-led approach to mining and a major step towards moving the company closer to water-less mining and reducing its footprint.

HDS demonstrates a new way to safely dispose of mining by-products and accelerates Anglo American’s progress towards the end of wet tailings storage. Ultimately, it allows the company to reclaim and reuse water, its most precious and undervalued resource, and create stable, dry, economically viable land long after mining ends.

The adoption of coarse particle recovery (CPR), another valuable FutureSmart Mining technology, was instrumental in the development of HDS, according to Newman. “It allows larger-size particles of material to be processed, reducing the need for grinding to a smaller size, thereby lowering energy consumption,” he said. “It also makes it easier for us to capture and drain water during the processing phase and recycle it.”

HDS targets the geotechnical and water recovery performance of filtered tailings but without the carbon footprint, Newman claims. Laboratory and proof of concept testing has proved the robustness of fines-free sand as a filtering medium – promising a safe, dewatered facility with the possibility of re-purposing otherwise sterilised land within months of closure. Through effective and permanent desaturation of the tailings, the geotechnical safety of the facility can be enhanced and deliver stability in excess of new Global Industry Standard on Tailings Management (GISTM) standards.

Anglo American has embarked on an ambitious demonstration of this technology, having built a bespoke 250,000 cu.m capacity HDS tailings facility at its El Soldado copper mine in Chile. The sand transportation and placement system was commissioned in August and tailings placement commenced at the start of November.

Data is being collected in real time on water balance, moisture content and consolidation, according to Newman, who said, by the end of the year, the company will be able to understand the degree to which tailings consolidation and dewatering is accelerated through the adoption of HDS.

“Our early results are already promising,” he said. “We have already measured water recovery at more than 80% (our initial target), and dewatering is continuing with up to 85% water recovery a possibility.”

Commencing the second layer of the sand drainage channel at the El Soldado trial, both Cell A and B have tailings with Cell A consolidated in less than two weeks

The trial will continue over the coming months with the second layer of the main sand berm being installed this month, followed by further tailings deposition.

Beyond the financial and environmental benefits, there is significant potential for the mining industry to leverage HDS to shift public perception on mining waste, according to Newman.

“Anglo American is keen to partner with other mining companies to accelerate the development and learning of this new technology and is open to synergistic licensing opportunities,” he added.

“We believe HDS could demonstrate that tailings can move from a risk which needs to be managed, to a safe, water-generating asset that, on completion, can deliver value-generating land to the perpetual benefit of our communities. By ushering in a new era of tailings disposal we are demonstrating how we are re-imagining mining to improve people’s lives.”

OZ Minerals, Boliden and Rio Tinto to collaborate on tailings initiative

OZ Minerals, Boliden and Rio Tinto have agreed to collaborate to unlock new and innovative technologies for managing tailings, helping the mining industry to further reduce risk while extracting the materials the world needs for the energy transition from what was previously regarded as ‘waste’, they say.

Under the umbrella of the Think & Act Differently (TAD) incubator initiative, the three companies will fund and support innovators who are working to reimagine mining and processing to eliminate, minimise, reuse or find value in mine tailings. The three companies will also collaborate on other selected innovations to pursue improved productivity while delivering benefits such as lower emissions and reduced waste.

The collaboration will support innovators by providing materials, funding, technical guidance and the potential for field trials at mine operations, the companies said. Innovators will retain ownership of their intellectual property rights, with a licence to use those rights granted to the companies that support them.

Michelle Ash, OZ Minerals’ Technology Executive, said: “We can accelerate technology much faster by working together and this is an example of how the industry can collaborate to support technology development. We hope this way of working and supporting innovators provides a model that can be replicated because accelerated technology development is likely to have a positive impact on our industry and society.”

Joanna Lindahl, Boliden Mines’ Sustainability Director, added: “By collaboration on generic challenges for the mining industry in a pre-competitive setting we will be able to make progress faster and more resource efficient. For the inventors and startup companies in the TAD incubator, it is also an excellent opportunity to get insights and business understanding from several different mining companies. We are very much looking forward for this collaboration and hope to find new opportunities to strengthen the industry in the future.”

Mark Davies, Chief Technical Officer for Rio Tinto, said: “It isn’t very often that competitors come together to collaborate on industry-critical work. One such area historically has been health, safety and environment, where we learned that sharing leading practices boosts our collective performance. We think collaborating on tailings management capability improvement could have a similar, industry-wide impact. We’re excited to be partnering with Boliden and OZ Minerals through the TAD program.”

The Think & Act Differently program, powered by OZ Minerals, works towards building an ecosystem of partners who will explore and accelerate themes that prioritise social and environmental responsibility for the development of the modern mine, the company says.

Photo courtesy of Exact Consulting

Rio Tinto’s Nuton ready to leverage its leaching R&D legacy

More than a few companies and technology providers claim to have solved the primary copper sulphide leaching conundrum, but only one has close to 30 years of R&D and the Rio Tinto name behind it.

Rio, through its Nuton venture, is the latest to table a solution to treat primary copper sulphides such as chalcopyrite, having introduced the company to the sector earlier this year in an attempt at growing the miner’s copper business.

At its centre is a portfolio of proprietary copper leach related technologies and capability that, Nuton says, offer the potential to economically unlock known low-grade copper sulphide resources, copper bearing waste and tailings, and achieve higher copper recoveries on oxide and transitional material. This allows for a significantly increased copper production outcome, according to the company.

One of the key differentiators of Nuton is the potential to deliver leading environmental performance, including more efficient water usage, lower carbon emissions and the ability to reclaim mine sites by reprocessing mine waste, it claims.

Column test work at Rio Tinto’s R&D centre in Bundoora, Melbourne

Adam Burley, Rio Tinto’s Nuton venture lead, said at the core of Nuton is an elevated temperature bioleaching process that can, in the right thermochemical conditions, deliver “peak” copper recovery from primary sulphides such as chalcopyrite.

“Taking advantage of naturally-occurring processes, we have nurtured a culture of microorganisms that establish and thrive in those optimised conditions,” he told IM. “The elevated temperatures are generated by the work of the bacteria; under the base case, we don’t need to heat the heap from external sources, which can often be financially and environmentally costly.”

This leaching core is enhanced by a range of “additives” and expertise that can, for example, deal with high precipitation and cold weather climates.

Having assembled and extensively tested this portfolio, Nuton and Burley are confident enough to state expectations of delivering greater than 80% copper recoveries from chalcopyrite ore with its process.

“This is, from our understanding, some way above the next best leaching technologies available,” Burley said.

The testing behind such numbers is extensive, dating back to 1994 when the company carried out its pilot heap leach operation and developed its initial predictive modelling capabilities at the Kennecott copper mine in Utah, USA.

“Since that time, we’ve conducted hundreds of column tests across tens of orebodies,” Burley said. “We have run columns at a range of scales – a metre high to 10 metres high – and a range of diameters – from tens of centimetres to 5-metre diameter cribs. Some of those range from tens of kilograms to 300 tonnes – large scale with a lot of instrumentation.”

Combining this body of work with a 70,000 t leaching trial the company carried out at Kennecott from 2012 to 2014, Nuton has been able to calibrate its computational fluid dynamic models to accurately predict a range of inputs and outputs for leaching suitability.

“We are left in a position today where we have a high degree of confidence in being able to evaluate the suitability of different ore types and Nuton’s leach response fairly quickly,” Burley said.

This has led to the company going out to market, partnering with companies that own deposits that pass the Nuton thresholds.

The company has signed deals with Lion Copper and Gold Corp, and Arizona Sonoran Copper Company to test out the technology on Lion’s copper assets in Mason Valley, Nevada, and Arizona Sonoran’s Cactus Mine and Parks/Salyer projects, in Arizona.

It has also more recently agreed a pact with McEwen Copper on the Los Azules project in Argentina.

These assets, agreements and potential leaching applications are all different – covering former operating mines and greenfield assets; earn-ins, exclusivity periods and equity stakes; and oxides and sulphides.

“We recognise that due to the high variability of copper deposits and mine waste that one size doesn’t fit all,” Burley said. “A single technology solution is unlikely to perform well at every site.

“Our approach is to work with our partners to understand site-specific characteristics, such as the mineralogy of the available ore and waste, designing a tailored approach by selecting the most applicable technology configuration from within the Nuton portfolio.”

And, according to Burley, these current and future agreements could see Nuton operate the equipment and plant associated with the Nuton process.

“In many cases, we envisage supporting our partners with an end-to-end process, including engineering, build out and operating the gear,” he said.

The test site at Kennecott being prepared and lined ready for the rock to be leached

While the sulphide copper recovery numbers are likely to take the headlines, Burley was able to point out several key differentiators from other leaching solutions targeting minerals such as chalcopyrite.

“Those recovery numbers are a step change, as opposed to an incremental improvement,” he said. “That gives us a lot more optionality in terms of the cutoff grade of the material we can process economically.”

And, with that higher resource utilisation, comes less waste and an overall higher process efficiency, meaning, under certain conditions, Nuton can compete with a pre-existing processing route such as a concentrator, Burley says.

“In some cases, in a greenfield setting, we could see a better economic and environmental outcome than a concentrator, particularly given no tailings or smelting is required, and you could have a finished product produced in country.”

He continued: “Our focus on ESG and our ability to process waste due to that low cutoff grade is one of the key differentiators that opens a whole set of use cases in the legacy mine domain too. Being able to restore and reclaim mine sites by reprocessing waste is very attractive.”

The eventual aim, according to Burley, is to deliver carbon-neutral copper from the Nuton process, yet Rio estimates it can already deliver 0.4 tonnes of CO2 equivalent for Scope 1 and 2 emissions per tonne of Nuton copper produced, compared with a global average of 5.2 tonnes of CO2 equivalent as per standard, conventional primary copper production.

Away from the technical elements, the “partnership” business model Nuton uses also stands out.

Nuton testing up and running at Kennecott (from previously mentioned trials)

“The approach is to work with our partners and assess the value case at specific sites, agreeing a commercial framework that works for everyone,” Burley said. “We are quite open minded as to what that might look like – it could be ownership and equity participation to royalty and licensing type arrangements.

“So, there is the financial strength Rio brings, as well as the deep technical expertise.”

These elements are clearly beneficial to any of Rio’s fellow mining companies that have projects with copper sulphides or those that will be transitioning to sulphide processing in the future, yet a lot of the progress made with these technologies was tied to the development of Rio’s own project, La Granja.

“In that case, part of the resource contains high arsenic and arsenic-related mineralogy,” Burley said of La Granja. “That was the trigger really for a concerted effort to look at an alternative to a concentrate and processing route. We made quite a number of Nuton breakthroughs in our study of that deposit.”

La Granja has been in Rio’s portfolio since winning the right to develop it in 2005, but is not currently in the development pipeline.

Asked if other assets within the company’s portfolio are potential Nuton candidates, Burley answered: “The potential exists to deploy Nuton within the Rio Tinto copper portfolio. We are currently evaluating a number of internal deployment options across our assets and joint ventures, but we also recognise the full value potential of Nuton – environmental and social, as well as financial – lies outside of the Rio Tinto portfolio.

“To capture the full size of prize that Nuton offers, we need to go out to market, which is what we have been doing pretty aggressively throughout the year and will continue to do going forward.”

The ICMM addresses mine tailings reduction ambition with new roadmap and initiative

Today, the International Council on Minerals and Metals (ICMM) has published a Tailings Reduction Roadmap which, it says, lays out innovative approaches and solutions capable of significantly reducing tailings from the mine life cycle, as part of a broader Tailings Innovation Initiative.

The initiative brings together a third of the global mining and metals industry to collaborate with technology innovators, including suppliers and academia, to accelerate technology for reducing tailings waste and to explore the potential to eliminate it in the long term, the ICMM says.

The Tailings Reduction Roadmap sets out short- and long-term technology options. These include mature solutions that can be implemented in the short term, such as coarse particle flotation technology to enhance the recovery of coarser particles of ore that have traditionally been seen as waste, and solutions with the potential to reduce tailings in more significant quantities, but that will require further development over the next 10-15 years, such as higher precision mining and artificial intelligence.

Developed through a series of engagements between technology suppliers, innovators and ICMM members, the roadmap offers strategic direction to the mining industry on how to accelerate the development and adoption of technologies to reduce tailings, the ICMM says. It addresses technological challenges, such as testing new technology on a different range of ore characteristics, as well as enabling factors, including business case and regulatory requirements, in parallel.

ICMM members are already piloting technologies laid out in the roadmap that match their commodities and site characteristics, so that learnings can be applied to solutions that can be scaled up to benefit the whole industry.

Rohitesh Dhawan, CEO of ICMM, said: “Catastrophic tailings failures in recent years including at South Africa’s Jagersfontein mine just last week have brought into sharp focus the need for urgent action to produce less tailings as we supply the metals and minerals that are critical for the energy transition and sustainable development. If we continue to use traditional production processes, we run the risk of multiplying tailings waste many times over. There is no easy solution, and we will continue to need tailings storage facilities into the future. However, this initiative signals our clear intent to act with urgency and purpose to find ways of minimising or potentially eliminating waste at every stage of the mining cycle.

“Work has already begun, but if we are to match our ambition, we need to work collaboratively in accelerating the types of breakthroughs that can be adopted widely in any existing or future operations around the world. Our ambition is that ICMM’s Tailings Reduction Roadmap and wider Tailings Innovation Initiative will help to identify and accelerate opportunities for wider collaboration and serve as a catalyst for advancing more partnerships between industry and technology innovators on piloting these technologies.”

ATG and Metso Outotec’s tailings-to-fertiliser tech progresses in BHP Tailings Challenge

Auxilium Technology Group (ATG), a start-up connected to the University of Arizona, in collaboration with Metso Outotec, has been announced as one of two finalists in the BHP Tailings Challenge, an international competition to promote the development of new technologies to reuse mine tailings.

Last year, ATG was one of 10 companies and academic research groups chosen to move on to the laboratory stage of the BHP Tailings Challenge, from an initial field of 154 applicants from 19 countries. Metso Outotec and ATG signed an agreement to collaborate on this initiative and, in April 2022, BHP chose two finalists, ATG and Americas Tailings Inc, a company that has developed a process to turn mine tailings into fertiliser products.

For the next phase, ATG plans to build a pilot tailings processing plant at the San Xavier Underground Mining Laboratory, owned by University of Arizona. Metso Outotec will contribute with advice on engineering and scale up using Metso Outotec products.

Metso Outotec supported the ATG process design concept by estimating engineering costs and providing Metso Outotec Plant Solutions technology competence. The concept considers pre-designed plant units known as “Process Islands” for almost all the process areas of the future plant, the company said.

Metso Outotec’s approach supported the project from optimal equipment sizing to optimising engineering costs and modularising the plant to meet future capacity requirements.

Mining companies like BHP are eager to find alternatives for the use of tailings, which are costly to store and regulated under environmental laws because they contain pollutants.

After initial cleaning of the tailings, the proposed process includes use of the material as construction aggregate or an insulating “geofoam” that can be sprayed or 3D printed to produce insulating blocks.

Hatch identifies opportunities to cut Australian tailings generation by as much as 30%

A new report from multi-disciplinary engineering, operational and development project, Hatch, estimates Australia’s mining waste can be reduced by 30% using already available technologies.

One of the biggest challenges currently facing the mining industry is managing the volume of tailings generated as minerals mining ramps up to meet the demands of the transition to renewable energy.

Undertaking an in-depth analysis to identify the technologies required to reduce or eliminate tailings of six key commodities (copper, gold, nickel, iron ore, coal and bauxite), Hatch investigated how tailings production would be impacted by applying the key technologies ‘themes’: advanced geometallurgy, ore sorting, advanced sensing and particle sorting, in-situ extraction, and preferential fracturing.

The company’s analysis revealed that technologies available today could reduce tailings by 20-30%, also identifying that, in the next 10-20 years, the integration of these technologies in future projects or expansions could provide an opportunity to reduce tailings by more than 50%.

Managing Director of Australia and Asia at Hatch, Jan Kwak (pictured), says the challenge of reducing tailings is a complex effort that is best solved utilising the innovative capacity of the entire mining supply chain.

“A balanced spread of researchers, METS (mining equipment, technology and services) companies, and operators in the mining industry are actively commercialising technologies,” he said. “Half (50%) of stakeholders identified are METS companies, whose core business is the supply of equipment and services of these technologies, indicating commercialisation is underway. This group was also present across the technologies that our analysis has shown to have higher TRLs (Technology Readiness Levels).”

The TRL ranking system measures the maturity of technologies, whereby Hatch graded technologies from zero (idea stage) to nine (commercial application).

For in-situ mining and preferential fracturing technology themes, there is a larger representation of research organisations and partnerships. This suggests collaboration is required to advance technological development, according to Hatch.

“It is vital that these stakeholders are highly engaged in the tailings reduction challenge in order to achieve the greatest cut through and introduce real change and advancement in the reduction of tailings, which will be needed to support the increase in mining activity while meeting emissions reduction targets,” added Kwak.

Repair, Reuse, Recycle: ERG’s critical minerals reprocessing journey

The Musonoi River Valley in the Katanga region in the Democratic Republic of the Congo (DRC) has, for some decades, been the site of land degradation resulting from inadequate and ineffective tailings and other waste management systems.

The local water system and surrounding land has been subjected to pollution from more than 83.2 Mt of legacy tailings spread over an area 11-km long and up to 2.5-km wide. Additionally, 41.1 Mt of tailings have accumulated at the Kingamyambo Tailings Dam.

Remediating and mitigating this damage is now a primary goal of Eurasian Resources Group’s Metalkol Roan Tailings Reclamation (RTR), a reprocessing facility dedicated to cleaning up the historic tailings left by previous mining operators in the Kolwezi area of the DRC. By reclaiming and reprocessing copper and cobalt tailings in the region, the company says its approach goes beyond ‘do no harm’, actively addressing a history of environmental degradation and pollution.

The legacy tailings are extracted through hydraulic mining and dredging, reprocessed and then re-deposited into a modern, closely managed and centralised tailings storage facility. This is subject to regular inspection, monitoring and reporting, supported by a dedicated Engineer of Record and an independent laboratory. Currently Metalkol RTR can produce 21,000 t/y of cobalt, which is says is sufficient for three million electric vehicle batteries, alongside around 100,000 t/y of copper, the company says.

ERG also has reprocessing operations outside of Africa, including at Kazchrome in Kazakhstan, which, it says, is the world’s largest high-carbon ferrochrome producer by chrome content.

Established in 2019, ERG Recycling – ERG’s specialised company aiming to become the largest entity to reprocess industrial waste into commercial products in Kazakhstan – has already implemented many projects including the commissioning of a new workshop that reprocesses slag, dust and other fine waste into high-quality briquettes. This program to reprocess Kazchrome’s 14.7 Mt of slag stockpiles has been expanded, now processing over 100,000 t/y of slag.

These operations have been enhanced by the development of new technology. Having completed the first trial in 2020, the Slimes 2 Tailings Reprocessing project at Donskoy GOK has the potential to enhance Kazchrome’s output of chrome concentrate by recovering 55% of the chromium oxide in chrome-oxide bearing tailings using innovative flotation technology, the company says.

In Brazil, at ERG’s integrated project, BAMIN, which produces a premium 67% Fe grade iron ore and is ramping up to become one of the country’s largest standalone iron ore exporters, the company’s transition from an upstream to a downstream tailings model ensured continued compliance with both local regulations and international standards, it said. The group continues to study additional technological enhancements to ensure the construction and operation of a world-class facility.

The environmental benefits of reprocessing projects like these are very significant for the business and critical to local communities, according to the company.

“As more attention rightly turns towards environmental, social and governance (ESG) issues, it is crucial that tailings are dealt with and stored properly,” ERG said. “Aside from preventing significant issues, such as dam collapses, by reprocessing and responsibly storing these tailings, we are reducing local pollution risks more generally, increasing air quality and decreasing the likelihood of leaching toxic substances into surrounding habitats and water systems.”

Given the legacy of environmental degradation and serious consequences it poses, it is also necessary for mining companies to explore novel ways of rehabilitating the environment.

For example, ERG has been working with a team of agronomists from the University of Lubumbashi in the DRC to look into the experimental planting of trees and their growing potential at the Kingamyambo tailings dam.

Looking forward, these operations will support the sustainable development of affordable batteries and other clean energy technologies.

By producing critical raw materials, such as cobalt, without the risk and cost of needing to develop new mining projects, ERG says it can help make electric vehicles and other renewable technologies more accessible, helping facilitating the net-zero transition.

Pictured above is Metalkol RTR, ERG’s reprocessing facility in the DRC: the world’s second largest standalone cobalt producer

EnviroGold highlights sustainable metal reprocessing credentials at Hellyer, Buchans Tailings projects

EnviroGold Global Limited says the precious (gold, silver) and battery metals (copper, zinc, lead) to be produced at the company’s Hellyer Tailings and Buchans Tailings reprocessing projects are expected to show a 96% reduction in greenhouse gas (GHG) intensity per gold-ounce-equivalent produced and an over 80% reduction in energy intensity relative to industry averages for conventional mining.

EnviroGold Global’s circular-economy business model is designed to produce precious, critical and strategic metals while reprocessing mine waste (tailings), which often contain significant quantities of valuable precious, critical and strategic metals.

EnviroGold Global’s analytics-driven approach to project origination and development leverages extensive mine production data, mill production data and geological records to identify tailings sites that are expected to contain significant quantities of residual metals due to refractory mineralogy and/or to the inefficiency of outdated technology used during legacy mining operations. In addition to recovering precious, critical and strategic metals, the company says it remediates the tailings consistent with environmental best practices, thereby reducing the environmental footprint of legacy mining. Further, by eliminating the extractive phase (mining) of metal production, the company expects to reduce the energy intensity of metal production by over 80%.

Leveraging the framework set forth by the World Resources Institute’s Greenhouse Gas Protocol, EnviroGold Global’s detailed assessments of expected Scope 1 and Scope 2 emissions for the company’s planned operations at the Hellyer Tailings and Buchans Tailings reprocessing projects indicate that the carbon intensity of the gold-equivalent ounces of precious, critical and strategic metals produced by the company will be 96% lower than industry averages for conventional mining. S&P Global Market Intelligence reports that the typical conventional mining operations generated nearly 1 tonne of CO2 per gold ounce produced.

Just last month, EnviroGold Global executed a binding definitive agreement with Hellyer Gold Mines Pty Ltd to reprocess the tailings owned by HGM at its namesake mine in Tasmania, Australia (pictured). Hellyer is owned by NQ Minerals, with the company having a plan to increase its financial year production to 1.5 Mt of tailings reprocessing in 2022, from the estimated 1.4 Mt in 2021. Earlier this month, EnviroGold announced that test work completed to date on its proprietary flowsheet demonstrated gold recovery rates of 83.5% and silver recovery rates of 94.6% from the refractory, volcanogenic massive sulphide tailings at Hellyer.

In 2021, it announced the execution of binding commercial agreements, which saw the Buchans River Delta Reclamation Project added to its portfolio of environmental remediation and asset reclamation projects, saying that it planned to deploy proprietary modular, scalable reclamation technology & systems able to process up to 1,000 t/d of reclaimed tailings to remediate the legacy tailings while removing environmental contaminants and reclaiming valuable commodities at the project.

EnviroGold Global CEO, Dr Mark Thorpe, said: “Whether serving as critical components for batteries, electric vehicles and clean-energy infrastructure, or as a store of value and hedge against inflation, metals have never been more critical to the modern, global circular economy. EnviroGold Global’s Metals Without Mining business model is designed to sustainably satisfy the world’s increasing demand for precious, critical and strategic metals by eliminating the most carbon and energy intensive phases of metal production, creating a win-win for corporate, community and environmental stakeholders.”

The Global Tailings Review reports that the total number of active, inactive and closed tailings storage facilities worldwide exceeds 8,500. The global footprint of tailings exceeds 280,000 Mt with an additional 12,700 Mt produced annually. The value of precious, critical and strategic metals contained in global tailings sites is estimated to exceed $3.4 trillion.

EnviroGold Global’s commercial strategy involves identifying, qualifying and developing tailings reprocessing opportunities, generally targeting tailings sites with at least 6 Mt of tailings and gross recoverable metal value of $124/t of tailings. Tailings sites meeting EnviroGold Global’s internal assessment criteria pass through an advanced screening process, which includes detailed technical/economic modelling incorporating expected recovery rates and site-specific process-level economic analysis.

The company has reviewed over 325 global tailings sites to date and has eight “major projects” in its global tailings reprocessing portfolio. EnviroGold Global expects to commence commercial metal production in 2022 at its Hellyer Tailings reprocessing project. The company will continue to acquire the rights to tailings reprocessing opportunities around the globe and subsequent to achieving commercial metal production at the Hellyer project will leverage strategic operating partnerships to scale up commercial metal production at multiple projects simultaneously.

Gravitas Minerals after iron ore recovery boost with Kalahari Process

Gravitas Minerals is leveraging its Optima Concentrator™ gravity separator to recover iron ore from tailings facilities and provide ‘value from waste’.

Using hindered settling, fluidised bed and autogenous dense medium separation technology to separate iron ore from gangue based on density, the Optima Concentrator has high throughput capacities of up to 40 t/h sq.m. This, the company says, is the ultimate low-footprint, water-only solution for fine iron ore recovery.

The company is using the Optima Concentrator to develop its so-called Kalahari Process™, which produces an iron ore product with a minimum grade of 63% Fe from various iron ore feed sources. The process has seen great success to date by yielding recoveries of up to 80%. In addition, the process is ideally set up for the direct reuse of water by dry stacking of both the product and tailings streams, according to the company.

An agglomeration stage added to the process can also produce fit-for-handling high-grade pellets, the company claimed. Another option would be to market the product as fines concentrate, a norm in the West African and Indian markets.

Gravitas Minerals Director, Tebogo Kale, said: “By utilising the Kalahari Process, iron ore producers can unlock the full potential of their mineral resource. In so doing, they can prolong the lifespan of their tailings’ facilities by up to 50%, reduce the disposal of iron ore tailings and the associated environmental impact, increase their revenues and ultimately boost profits.”