The mining sector stands at a crossroads. On one side lies an unprecedented opportunity: the transition to clean energy technologies, electric vehicles and digital infrastructure is driving a surge in demand for critical metals like copper, lithium, nickel, cobalt and graphite. The International Energy Agency projects that the combined market value of these minerals will more than double to $770 billion by 2040 in its net zero scenario.
On the other side lies one of the industry’s greatest challenges: tailings. Declining ore grades mean that more rock must be mined and processed to recover the same unit of metal, generating larger volumes of tailings than ever before. A 2023 study published in “Resources, Conservation and Recycling” projects mining waste volumes will rise steeply by 2050, with copper alone set to produce billions of tons of tailings annually.
Water and tailings are inextricably linked. Ore processing requires large volumes of water, while tailings storage generates losses through evaporation and seepage. In many jurisdictions, water scarcity is already severe, and communities are increasingly unwilling to accept operations that dominate supplies or jeopardize them through contamination.
Following tailings dam failures at Mount Polley (Canada, 2014), Samarco (Brazil, 2015) and Brumadinho (Brazil, 2019), loss of life and environmental devastation prompted widespread regulatory reform. Public awareness of these risks is high and trust in the sector is fragile.
At the MIT-hosted Global Summit on Mine Tailings Innovation in September 2024, convened with the International Council on Mining and Metals (ICMM), experts concluded that rethinking tailings is not optional. “Tailings are a risk and a constraint to meeting future minerals demand,” the whitepaper summarizing the event warned.
Satish Rao, managing director at Clareo and co-author of the paper, told E&MJ: “Tailings are front and center in societal opposition to new mining projects. Communities increasingly see tailings as the line in the sand for whether a project gets approved.”
In the whitepaper, Rao and his co-author, Grant Caffery – director, Australia at Clareo, set out a continuum of approaches in tailings management, from incremental improvements such as dewatering to radical options such as in-situ recovery, that can help mining companies form a technology roadmap toward zero waste. This article explores some of those pathways and their feasibility.
Incremental vs. Transformative Change
For decades, progress in tailings storage has been dominated by incremental technological improvements and strategies. These range from installing filters and adopting thickened or paste tailings systems, to introducing dry stacking, where climate permits. Each reduces risk, but the fundamental paradigm — grinding vast quantities of ore and storing the waste in large impoundments — remains.
“There’s a continuum of approaches,” Rao explained. “Some, like new leaching technologies, have clear economic incentives and are attracting venture funding. Others, like in-situ recovery, still need regulatory guidance and proof of scalability.”
Caffery stressed that economics should be the biggest driver of progress in this area. “It’s economically beneficial to get rid of tailings,” he said. Grinding 99.5% of material to get 0.5% of the good stuff is an inefficient way to mine.”
This reframing — tailings not as an unavoidable by-product but as inefficiency — has resonated with innovators. For example, new chalcopyrite leaching approaches promise to unlock lower-grade resources in the near term, while simultaneously reducing tailings volumes.
Yet the leap to transformative change is daunting. Reimagining concentrators to eliminate fine grinding or replacing conventional processing entirely with in-situ methods, requires not just new technologies but new mindsets.
Rao offered the example of Rio Tinto’s Jadar project in Serbia. Despite proposing to use filtered tailings and dry stacking, community opposition remained fierce. “That project is proof that, in some cases, incremental isn’t enough,” he said. “Communities are increasingly demanding, not just safer tailings storage methods, but less or even none at all.”
Crises can also accelerate transformation. After multiple tailings disasters in Brazil, Vale committed to eliminating conventional wet tailings disposal at its iron-ore operations, pledging that the massive Carajás complex will be water-free by 2027. The scale of this shift demonstrates that rapid change is possible when industry focus aligns with societal pressure.
“Radical innovation is always a bridge too far — until you’re standing on that bridge,” noted Caffery. “That’s when industry makes the leap.”
The current geopolitical and related supply crisis in critical minerals, required in applications such as consumer electronics, medical devices, renewable energy and fighter jets, offers another tantalizing opportunity. A study by researchers at the Colorado School of Mines, estimated the quantities of critical minerals being mined and processed every year at U.S. mines, but not recovered. Instead, these end up as discarded tailings. The analysis, reported in Science, found that unrecovered byproducts from U.S. mines could meet demand for 68 out of 70 critical minerals.
Could the mining sector and its stakeholders utilize the current critical minerals crisis to address long standing challenges regarding tailings? To answer this question, a detailed analysis of the minerals in waste streams is needed, along with investments in recovery technologies, and policy and regulatory support.
From Dewatering to In-situ Recovery
The Clareo whitepaper outlines five pathways that together form a roadmap toward zero waste. These are as follows:
1. Optimize recovery: Maximizing recovery from tailings is an immediate opportunity. Reprocessing can extract metals overlooked during initial processing, including critical minerals, like scandium and rare earths. In Sweden, LKAB and Boliden are pioneering industrial symbiosis through the creation of a circular business park that will valorize tailings. Water recovery is equally vital. Dewatering through advanced filtration, cycloning, or chemical additives not only improves stability but reclaims scarce water for reuse.
2. Eliminate waste early: Rejecting waste before it enters the concentrator reduces energy and water usage as well as tailings volumes. Ore sorting and grade engineering approaches pioneered by CRC ORE exemplify this. Precision mining technologies — drawing on methods developed in oil and gas, like directional drilling — could one day bring only ore, not waste, to the surface.
3. Process everything: Emerging technologies aim to derive value from the entire rock. Molten oxide electrolysis, for example, can convert mixed materials directly into metal using renewable electricity. Supercritical CO2 fluids and biomining microbes promise selective extraction without grinding.
4. Transform leaching: Heap leaching has long been used for copper and gold, but some chalcopyrite ores remain stubborn due to passivation layers. New reagents, oxidants, catalysts and microbial cocktails are breaking down these barriers. “We’re close to unlocking the benefits of leaching in a massive way,” Rao said. “Success here would revolutionize copper processing by bypassing concentrators entirely.”
5. In-situ recovery: Perhaps the most radical approach, in-situ recovery injects lixiviants into orebodies and pumps pregnant solutions back to surface. While promising, challenges remain, namely ensuring ore permeability, controlling solution flow and navigating unclear regulations. Still, the prize — mining without waste rock or tailings — is compelling.
Caffery envisioned the future: “A copper mine of the future could be nothing more than a few wells in the ground, like a shale oil field. No moving material, no tailings, fully automated.”
Brownfield vs. Greenfield Opportunities
While both greenfield and brownfield projects present opportunities for improvements in tailings management practices, greenfield projects allow companies to design for alternative tailings strategies from the outset and hence, optimize — both from a technical and economic perspective — for more radical strategies. For example, processing circuits can integrate coarse particle flotation (CPF), bulk ore sorting, or tailings filtration without retrofitting challenges, and flowsheets can be configured for minimal water and energy usage.
However, the past decade has seen the mining industry shift its focus away from early-stage exploration towards brownfield projects and expansions — according to S&P Global, 70% of new copper production that came online between 1990 and 2023 originated from deposits discovered during the 1990s.
While the scope for change at these projects is less transformative, their sheer volume means that the greatest opportunities for industry wide improvements in tailings practices arguably lie in these projects.
“Copper discoveries in particular are going to come almost entirely from brownfields in the future,” said Caffery. “If you’re bolting technologies onto existing concentrators, it’s very hard to integrate strategies, such as dry stack tailings, but there are always improvements that can be made. On the other hand, if you’re building a new concentrator as part of an expansion, miners can think about optimizing the whole system.”
Rao stressed the need for holistic business cases: “Mining companies can’t view tailings in isolation,” he said. “They need to account for production efficiency, OPEX savings, closure liabilities, water savings and social license. Only then do the economics become compelling.”
This integrated view is crucial, particularly as many brownfield mines face declining grades. Companies may need to expand concentrators or shift underground, creating windows of opportunity to adopt new technologies.
Caffery suggested thinking in terms of “khaki-field” projects — hybrids between brownfield and greenfield. “These are expansions where miners can fence off new concentrators or leach pads, and design them differently, even if the legacy plant remains conventional,” he explained.
Terraflowing dewatering technology offers flexible thickening solutions for better water recovery. (Photo: Weir)
Overcoming Economies of Scale
The trend towards greater throughputs at concentrators means that the quantity of tailings being produced is increasing. From an engineering perspective, mines can build bigger pipelines and pumping stations to manage this, but, in many instances, this will only exacerbate existing logistical challenges and oversight requirements.
Erik Vlot, global tailings process director at Weir, spoke to this. “Tailings dams are rising, which means operators need to make decisions around what to do with their diminishing capacity,” he told E&MJ. “Depending on the site, there will be constraints within which these decisions have to be made (i.e. regulatory requirements, space etc). These decisions also inevitably involve challenges around oversight; for instance, there are important geotechnical and environmental considerations that must be taken into account.”
Mines can, in theory, continue to build larger tailings storage facilities (TSFs) and pumping systems, but at some point, it’s prudent to ask whether this approach is in the best interest of stakeholders. As Vlot pointed out: economies of scale do have a ceiling.
“Operators need to think about whether they want one large tailings pumping system, for example, or multiple smaller systems. It’s important to always keep in mind the operational scenarios and design the systems accordingly,” he said.
With a single pumping system, reliability issues could require the system to be shutdown which would halt production. But if an operation has multiple smaller systems and there are reliability issues with one, or even when scheduled maintenance needs to be performed, it will still have some pumping capacity, which would mean less downtime.
“This then provides operators with greater flexibility,” said Vlot. “For instance, if a system is sized for one flow and the pipeline needs to operate at between, say, 70-100% capacity to maintain velocity, it’s not difficult to envisage a situation in which the mine might have to run its thickeners empty. This is obviously inefficient and energy intensive, and that’s why it’s important to keep in mind the operational scenarios and design the systems accordingly.”
Weir is advancing digital mining with smarter monitoring, process optimization, and full mining value chain visibility. (Photo: Weir)
Practical Solutions for Today and Tomorrow
Weir is working hard to develop tailings flowsheets that incorporate new technologies and management strategies, both at the incremental and more radical end of the change continuum.
“This approach means that we’re taking a more holistic approach. For instance, rather than focusing solely on handling tailings flow as one big volume, we’re looking at separating out the different size fractions, which then allows operators to handle them in different ways,” said Vlot. “The operator can apply cycloning or screening technology to dewater the tailings, which can remove the coarser fractions. This has benefits in terms of reducing the load on the thickener, while also allowing them to reduce the size of their pipeline.”
Another solution that miners are increasingly thinking about and starting to implement is CPF technology. Vlot explained that with an existing SAG — ball mill — pebble crushing circuit (SABC), introducing CPF reduces the load on the comminution circuit, because it reduces the amount of material that needs to be finely ground. This allows mines to run their plants at the same or improved recovery (if they can capture valuable metals that might have been lost in conventional flotation at a coarse grind size), but at a higher throughput, while also producing a coarser tailings stream.
“When designing and developing any solution there are always going to be trade-offs that need to be considered and that’s no different for CPF,” he told E&MJ. “It does represent a significant capital investment, and in brownfield projects, it must fit within the existing footprint. So, these things always need to be assessed on a case-by-case basis.”
CPF also requires additional water, which can be recovered, but that needs to be investigated during the feasibility stage. Similarly, there are additional energy requirements, so all these factors — and more — need to be weighed against the increased throughput. That said, in most instances CPF can deliver operational benefits and Vlot believes it will be more widely implemented in the future.
“There’s growing consensus across the mining industry that there needs to be changes in the way that tailings are handled,” he said. “As a result, Weir is involved in some exciting projects that could really help make some significant progress in reducing tailings’ environmental burden. For instance, in South America, we’re working on various studies with partners to investigate how to get a fines-free product that is suitable for alternative TSF disposal scenarios.”
In Australia, Weir is also conducting test work with its Terraflowing dewatering technology to explore alternative approaches to thickening as a way of recovering more water. It’s an approach that the team expects to provide more flexible flowsheets, particularly for those operating in arid regions.
In August 2025, Weir also signed a strategic cooperation agreement with MINEXXT, Inc., to integrate advanced thickening technologies into its technology portfolio. Early projects are already underway in Australia and Kazakhstan, combining Weir’s global reach with MINEXXT’s specialized expertise.
“The value of this cooperation agreement lies in having access to world-class thickening technology,” said Vlot. “Thickening will remain important as part of tailings flowsheets and the challenge around thickening of fines and ultra fines can be addressed with MINEXXT patented feedwell technology.
“Collaboration is at the heart of what we do. If there are products or solutions that aren’t part of our portfolio, then we’ll work with partners to ensure we can provide the best solutions to our customer based on their needs and requirements. We’ve done this with Eriez, too, and it’s a partnership that benefits everyone.”
Mindset and Collaboration Define the Path Ahead
Despite significant technical progress in tailings handling and storage, some cultural and structural barriers remain. Mine operators tend to prioritize proven technologies and flowsheet designs over innovation. Once a plant is built, it typically operates for decades with minimal changes.
“Mindset is the biggest challenge that the industry faces in tailings management,” said Caffery. “The industry is built on ‘build it big, build it to last.’ But what if we built to change? Modular, adaptable concentrators would allow us to bolt on new technologies as they mature.”
Rao stressed the importance of collaboration and knowledge-sharing in overcoming current challenges. “When a pilot fails, the learnings often stay siloed. If we shared them more broadly, the whole industry would move faster,” he told E&MJ.
Vlot agreed: “While innovation is a popular topic of discussion these days, mining remains a risk-averse sector, so it’s important that OEMs, including Weir, work closely with consultants and engineering firms to encourage adoption by validating more innovative technologies and solutions, and demonstrating that they can deliver quantifiable benefits.”
Scaling the adoption of innovative approaches will also require greater alignment between miners, OEMs, regulators and communities. Social license pressures may ultimately force the pace. “Water and tailings are two sides of the same coin,” Caffery observed. “Communities will no longer accept mines that squander water or risk catastrophic failure.”
Toward Zero-waste Mines
It’s clear that the mining industry can no longer afford to treat tailings as an afterthought. As demand for critical minerals surges, society’s tolerance for waste and risk is shrinking.
Incremental measures — filtration, CPF, dry stacking — offer important improvements today, while transformative approaches — leaching breakthroughs, ore sorting and in-situ recovery — promise a future where tailings could disappear altogether.
That future may seem distant, but progress is accelerating. Vale’s use of dry processing, Rio Tinto’s ore sorting trials and Weir’s innovative partnerships are proof that the industry is capable of significant change when compelled.
Caffery’s vision of a well-field mine without waste may sound futuristic, but the seeds are already being planted. Whether the industry embraces them proactively or waits for the next crisis remains to be seen. What is certain is this: tailings are no longer just a technical challenge. They’re central to mining’s license to operate and grow.
Codelco Advances Talabre Tailings Expansion With Industry-leading Engineering and Equipment
Chile’s state-owned copper giant, Codelco, is pushing forward with its Talabre Thickened Tailings Project (Proyecto Relaves Espesados Talabre or PRET) in the Antofagasta Region, a massive infrastructure effort designed to sustain mining operations at its northern mines while improving environmental performance. This project will replace and extend the existing Talabre tailings dam, which currently receives waste from the Chuquicamata and Ministro Hales operations. As the existing facility nears the end of its operational lifespan, the PRET aims to deliver a modern, efficient, and environmentally responsible solution.
Central to the PRET initiative is a comprehensive engineering package that spans structural design, hydromechanical systems, and digital infrastructure. Global engineering firm, Knight Piésold, has led the conceptual and basic engineering design for the Stage IX raise of the Talabre dam. The expansion will increase the dam crest from approximately 2,493 meters above sea level to around 2,503 m, enabling additional storage capacity for thickened tailings over a 20-year operational horizon.
Knight Piésold’s scope also includes the design of tailings and reclaim water pumping systems, piping and distribution networks, water recirculation infrastructure, and the electrical and automation systems required for integrated control.
Innovative Equipment for Thickened Tailings
To efficiently handle the high-density tailings slurry — with solids concentrations up to 70% — Codelco has turned to TAKRAF Group for critical dewatering infrastructure. In late 2024, TAKRAF was awarded a contract to supply seven 60 m diameter DELKOR High-Density Thickeners, each featuring 14 MNm maximum operating torque drives. These units represent the highest torque thickeners ever delivered by DELKOR, tailored to handle the high-solid tailings from Codelco’s flagship mines.
The package also includes DELKOR shear-thinning systems and auxiliary equipment, designed to improve slurry flow efficiency and water reclamation rates. TAKRAF’s contract encompasses engineering services, onsite technical support during commissioning, and long-term spare parts provisioning, ensuring operational reliability and performance.
These high-performance thickeners should enhance water recovery rates by reclaiming process water for reuse within the concentrator circuits.
Powering Tailings Transport With Weir Group
Complementing the dewatering infrastructure is a robust tailings transport solution supplied by the Weir Group. Under a $54 million contract, Weir is delivering a suite of GEHO positive-displacement and Warman centrifugal pumps capable of transporting thickened tailings across large distances from the Chuquicamata, Ministro Hales and, eventually, Radomiro Tomic mines.
Designed for a throughput exceeding 10,000 dry tons per hour, the pumping system integrates Weir’s NEXT intelligent control platform, which optimizes performance and energy efficiency while reducing maintenance downtime. This marks the single largest GEHO pump order in Weir’s history and showcases the growing demand for advanced, sustainable tailings transport technology.
A Phased, Sustainable Expansion
PRET is expected to enter operation in H1 2027. It is structured in two main phases: phase 1 covers tailings from Chuquicamata and Ministro Hales, while phase 2 will incorporate infrastructure to manage additional volumes from Radomiro Tomic. The project is designed for a lifespan of at least two decades and aligns with Codelco’s environmental commitments, including reductions in particulate emissions, tailings footprint and water consumption.
By integrating high-torque thickeners, advanced pumping solutions, and detailed engineering, Codelco is setting a new standard for tailings storage and reuse in arid, high-altitude environments.