Recovering minerals and finding new uses for leftover materials is technically possible, but implementing these solutions at scale faces economic and regulatory barriers, as well as safety requirements. The challenge also involves reducing the volumes generated from the design stage of mining operations.
How far are we really from a mining industry that generates no tailings requiring storage in disposal facilities?
Technologies to recover water, extract minerals and turn this waste into new materials already exist. The problem is that the solutions with the greatest potential to reduce final disposal are precisely those facing the greatest difficulties in operating at an industrial scale.
Chile generates between 700 million and one billion tonnes of tailings each year and has accumulated approximately 6.5 billion cubic meters of this waste, according to the Center for Research in Sustainable Mining (CiMS JRI). “Given the scale and variability of the tailings generated in Chile, it is unrealistic to think that a single solution will solve the problem.
We need a combination of technologies that complement one another and respond to the characteristics of each material and operation,” says Millaray Hernández, General Manager of CiMS.
From recovery to transformation
The path toward “zero tailings” begins with recovering the water used in mineral processing. This involves thickening technologies, which concentrate solids and allow some of the water to be recirculated into the production process, as well as dewatering and filtration technologies, which further reduce the material’s moisture content before disposal.
The next step is to make use of the solids. Secondary mining seeks to recover copper, iron and other valuable elements contained in tailings, while reuse and valorization technologies aim to find new uses for them, ranging from filling underground mine voids, or backfilling, to manufacturing construction materials.
According to an analysis presented by CiMS at Tailings 2026, combining water recovery technologies with the reuse of tailings as mine backfill could reduce the proportion of the initial mass requiring final disposal from 41% to 28%. The calculation includes both the solids and the water contained in the tailings.
Although the reduction is significant, it remains far from achieving zero tailings. “The main gap is that these technologies—reuse, valorization and secondary mining—have not reached the scale needed for industrial implementation, whether because of a lack of
resources or infrastructure, and especially because we still need mining companies to allow us to test these solutions under actual operating conditions,” Hernández says.
CiMS is seeking to close some of these gaps through a Corfo technology program that develops solutions to recover valuable elements and transform tailings into new materials, although these still require validation at a larger scale.
The economic equation
The fact that a technology can recover minerals or reuse tailings does not necessarily mean that implementing it is profitable. According to Andrés González, Head of Mining Industry Analysis at Plusmining, the decision depends both on the value that can be obtained from these materials and on the costs avoided by reducing conventional disposal.
“A mining company would need to see that the net present value of reusing, valorizing or reprocessing its tailings exceeds that of continuing with conventional disposal, taking risks and future costs into account,” he says.
Higher metal prices, more efficient recovery technologies or new markets for derived materials could improve this equation. It may also be economically advantageous if the reduction makes it possible to avoid building a new tailings storage facility, postpone its expansion or reduce the closure and post-closure costs of these facilities.
Chile already has industrial applications for recovering minerals from tailings. For example, Minera Valle Central recovered approximately 29,000 tonnes of copper and two million pounds of molybdenum in 2024 from El Teniente’s tailings. In Atacama, CMP’s Magnetite Plant recovers iron from Minera Candelaria’s copper tailings, with 24.8 million tonnes of tailings reprocessed in 2025, according to its sustainability report.
Both examples demonstrate that value can be recovered at an industrial scale, although this does not necessarily reduce the volumes requiring final disposal by the same proportion.
“Tailings are produced in enormous volumes, while their commercial value per tonne tends to be relatively low. Therefore, valorization must be competitive not only in technological terms, but also in processing, transportation, demand and scale,” González adds.
But another difficulty emerges here. The cost of further reducing disposal can exceed the benefits obtained. “There is a pattern of rising marginal costs: the first tonnes of tailings may be relatively inexpensive to recover or reuse, but as processing advances, the remaining fractions tend to have lower commercial value, greater technical difficulties or higher processing and transportation costs,” he explains.
Beyond technology
Tailings do not have a uniform composition, which affects their potential for reuse. “Their physical, chemical and mineralogical characteristics can limit their reuse potential and require additional treatment to ensure their stability and environmental safety. Therefore, not all solutions are applicable to every operation,” warns Francisca Rivero, General Manager of the University of Queensland’s Sustainable Minerals Institute International Centre (SMI-Chile).
For Rivero, the challenge also requires incorporating waste reduction into mining projects from the design stage. “Rather than understanding zero tailings as an immediate or universal target, we should see it as a horizon for transformation that drives progressive, measurable and verifiable reductions in the volumes requiring final disposal,” she says.
Tabatha Chávez, Innovation, Data and Research Manager at the International Council on Mining and Metals (ICMM), emphasizes safety. “Anything we say about tailings must begin with safety. Regardless of the technology we are discussing, including those aimed at achieving or approaching zero tailings, the primary objective is to prevent harm to people and the environment,” she says. In this regard, the organization is promoting the Tailings Innovation Initiative, which seeks to overcome the regulatory, financial and collaboratio barriers hindering the industrial adoption of new technologies.
There is also a race against time. According to Hernández, large-scale mining could face storage capacity constraints within the next two decades, while implementing new technologies can take between five and 10 years or more, depending on their complexity. The challenge of zero tailings is to bring solutions to an industrial scale before storage capacity limits operations.
Source: El Mercurio