Highlights
- A comprehensive study reveals mine tailings as a significant untapped source of rare earth elements, with recovery potential of 36-78%.
- Tailings valorisation offers a sustainable approach to expanding rare earth supply without new mining operations, potentially cutting carbon emissions.
- Global REE demand is expected to exceed 305,000 tons by 2025, making tailings reprocessing a critical strategy for supply chain resilience.
A sweeping new review published in the Journal of Cleaner Production (Vol. 520, August 2025) shines a spotlight on a rarely tapped goldmine in the critical minerals race: mine tailings. Led by Dr. Réka Hajdu-Rahkama (opens in a new tab) and Dr. Päivi Kinnunen (opens in a new tab) of Finland’s VTT Technical Research Centre (opens in a new tab), the study systematically charts the hidden potential of rare earth element (REE) recovery from the vast waste streams of global mining.
As global demand for rare earths—especially neodymium, praseodymium, and dysprosium—soars with electric vehicle and wind turbine growth, the researchers argue that tailings—the byproducts of mining—represent the second-largest REE resource globally, and a key to supply chain resilience.
Study Design
The team reviewed over a decade of international literature and case studies on REE-bearing tailings from iron, phosphate, uranium, gold, and rare earth mines, integrating geochemical, environmental, and economic datasets. They examined both conventional and biological recovery methods, environmental risks, and commercial efforts underway in Europe, North America, and Australia.
Key Findings:
- REE recovery rates from traditional mines average only 36–78%, leaving substantial value in tailings.
Tailings from mines like Bayan Obo (China), Mountain Pass (U.S.), and LKAB (Sweden) may contain REE grades as high as the original ore.* Novel bioleaching and biosorption methods are well-suited to low-grade tailings, offering lower chemical use and energy demands.
- Tailings valorisation can cut carbon emissions and reduce environmental risks from radioactive or toxic waste.
Implications
For investors, miners, and policymakers, the message is clear: tailings are not waste—they’re a future resource. With global REE demand expected to exceed 305,000 tons by 2025, tailings reprocessing offers a way to expand supply without new pits, major permitting hurdles, or long lead times. Projects like LKAB’s in Sweden and Prospech’s in Finland are already moving forward.
Limitations
Tailings are heterogeneous and often low in REE concentration. Recovery costs depend on mineralogy, contaminant management, and technology development. Few tailings recovery operations have yet been proven at commercial scale.
Conclusion
As the U.S. and its allies look to de-risk rare earth supply chains from Chinese control, tailings valorisation could become a strategic pillar. But realizing this vision requires investment in advanced processing, public-private coordination, and a mindset shift: from waste management to resource recovery.
CitationHajdu-Rahkama, R., & Kinnunen, P. (2025). Tailings valorisation: Opportunities to secure rare earth supply and make mining environmentally more sustainable. Journal of Cleaner Production, 520, 146147. https://doi.org/10.1016/j.jclepro.2025.146147 (opens in a new tab)
Rare Earth Exchanges™
Any quantitative data results for REE concentrations in iron ore mine tailings?