The mining industry is under mounting pressure to find an alternative approach to managing tailings – the residue left over after the target component has been extracted.
As efforts grow around implementing renewable energy and electric vehicle fleets, miners are tasked with extracting more metals than ever. But with tailings dam failures piling up and environmental, social, and governance (ESG) priorities becoming critical to survival, the pressure to manage tailings more safely and sustainably is constantly on the rise.
While developing safer management strategies and practices remains a key focus in the industry, many miners are looking at tailings recovery and beneficial reuse opportunities as an alternative to storage. As a leader in waste transformation, FEECO continues to be a valuable resource for those looking to reuse or recover their tailings through feasibility testing and process development services.
Factors Influencing Tailings Management
Several factors are culminating in an ever-tightening squeeze on the mining industry and how it handles its leftover waste:
More Metals = More Tailings
The reality of just how metal-intensive a low-carbon economy is going to be continues to set in; from zinc and aluminum, to copper and nickel, renewable energy technologies and vehicle electrification demand much greater quantities of metals than prior technologies.
Add to that changing infrastructure and the economic rise of developing countries, and the world is in need of a serious amount of metals. But the more metals we mine, the more tailings we produce, and with aging tailings ponds already a problem, a pressing need to find a better approach is imminent.
Declining Ore Grades & Resources
The need to mine more metals is a compounding problem for tailings; not only does more mining yield increased tailings, but the more we mine, the more we exhaust high-grade ore resources.
Declining ore grades mean miners have to mine higher quantities of material to obtain the same quantity of the target component, yielding even more tailings in the process.
In the case of some materials, resources are already running thin, and geopolitical and social concerns add to already-challenging circumstances.
Mounting Tailings Failures
The most pressing reason for finding a better way to manage tailings is the rising occurrence and catastrophic consequences of tailings dam failures. The most recent catastrophic breach occurred in 2019 at the Brumadinho Mine in Brazil; the collapse devastated the surrounding community and took the lives of nearly 300 people, making global headlines and inciting demand for change.
Earlier this year, the Responsible Mining Foundation released a statement citing data gathered in response to the Brumadinho disaster stating that up to one third of the world’s current tailings storage facilities (TSF) are compromised and in need of urgent attention.
Changes in Tailings Management Underway
The Brumadinho failure ultimately became a catalyst for long-overdue change in the industry. The disaster prompted a wave of initiatives, including a global push to create a first-of-its-kind public registry of tailings storage facilities.
Tailings facilities and their owners have come under a microscope, with every aspect of these facilities, from permitting and design, to monitoring and even post-closure, being scrutinized and held to a higher standard.
The Global Industry Standard on Tailings Management, a conglomeration of the International Council on Mining & Metals (ICMM), the United Nations Environment Program (UNEP), and Principles for Responsible Investment (PRI), also came to fruition in 2020. The group hopes to improve tailings management to the point of zero harm to people and the environment through a framework of industry-wide guidance.
The Mining Association of Canada also recently updated their guidelines for tailings management, holding Canadian miners to a higher standard.
Tailings Recovery and Reuse
Properly managing existing and new tailings facilities throughout their entire lifecycle is a crucial and undeniably important step in reaching the zero-harm goal, but simply managing tailings overlooks their value as a potential resource; these “wastes” could serve as a source of the metals (and other materials) our changing world so desperately needs.
Tailings still contain a small amount of the target component, be it gold, copper, or otherwise, in addition to other economically valuable materials such as alumina, zinc, iron, nickel, and more. Constantly advancing technologies in extraction, paired with the higher demand for materials, has made tailings an increasingly attractive resource.
Many old tailings piles, for example, were previously considered too low-grade to economically mine with the technology available at the time, but with today’s technology, are now being considered anew.
Many tailings hold potential for beneficial reuse applications as well, such as in construction materials and even soil amendments.
Tailings Recovery & Reuse Process Development Testing
Development around such applications is constantly underway as miners look at ways to recover what they can and reuse what they can’t. BHP is currently hosting a contest to develop a business model around reusing their copper tailings. And last year, Vale opened a pilot plant to transform tailings from one of their iron ore mines into construction products, to name a few.
FEECO has been actively involved in a number of efforts to recover or reuse tailings through feasibility testing and process development services in the FEECO Innovation Center. The facility boasts several different types of batch- and pilot-scale equipment spanning agglomeration, drying, and high-temperature thermal processing to help companies evaluate potential recovery and reuse processes.
Many types of tailings hold value that is simply not accessible in their existing form, but by agglomerating, drying, or thermally processing them, their value is unearthed.
Fly ash, for example, can be pelletized into an effective lightweight aggregate. Similarly, bauxite tailings (red mud) are a rich source of several metals, including rare earths. Many companies are exploring the extraction of such metals with the use of a rotary kiln. The opportunity to recover and reuse tailings holds significant and diverse potential and would also contribute to the goal of a circular economy.
Conclusion
The mining industry is under increasing pressure from all angles to better manage tailings. This, along with the growing demand for metals, is pushing the industry to look at tailings as a resource instead of a waste, with many opportunities on the horizon.
FEECO’s testing and process development services have been and continue to be a key resource for evaluating recovery and reuse opportunities, and designing the equipment needed to bring the operation to commercial scale. For more information on our process development services or custom equipment, contact us today!