RESOURCES
Uranium-Rich Mine Water
Hundreds of active, inactive and legacy uranium mines worldwide generate water requiring continuous treatment to remove dissolved uranium and associated radionuclides before environmental discharge. Depending on deposit type and hydrogeological conditions, uranium concentrations typically range from 0.1 to 50 mg/L, with some sites exceeding 100 mg/L, while these waters may also contain economically significant concentrations of rare earth elements (Nd, Pr, Dy, Y, Sc), vanadium, molybdenum and other critical metals. A single uranium operation may treat 1–20 million cubic metres of water annually, representing a potential recovery of 1–500 tonnes of uranium per year, depending on water chemistry and treatment volumes. Major opportunities exist across Canada, the United States, Australia, Kazakhstan, Namibia and Europe, where water treatment often continues for decades after mine closure. Selective recovery technologies offer the opportunity to recover uranium together with critical minerals, transforming a long-term environmental liability into a strategic source of critical raw materials while reducing treatment costs and improving water quality.
Tailings & Mineral Processing Residues
A single large or historic tailings facility may contain 20–100 million tonnes of material. At grades of 300–1,000 ppm total rare earth oxides, such a facility could contain approximately 6,000–100,000 tonnes of REOs in place.
Not all of this material would be technically or economically recoverable, and only part would consist of high-value magnet elements. Nevertheless, a facility containing 2,000–5,000 tonnes of recoverable Nd, Pr, Dy and Tb could theoretically offset approximately 7–25% of an illustrative 20,000–30,000-tonne annual magnet-REE supply gap.
The comparison is illustrative rather than a universal reserve estimate. It demonstrates why large legacy tailings assets can become strategically meaningful resources when selective recovery becomes technically viable. Magnet rare-earth demand has already doubled since 2015 and is projected to rise by more than 30% by 2030.
Bauxite Residue (Red Mud)
A major alumina refinery can generate approximately 1–3 million tonnes of bauxite residue annually, with much larger volumes accumulated over decades. Europe alone produces substantial annual residue volumes, and only a small share is currently reused.
Depending on the bauxite source, one million tonnes of residue containing 500–1,500 ppm total REEs could hold approximately 500–1,500 tonnes of rare earth elements. At scandium concentrations of 50–120 ppm, the same material could contain roughly 50–120 tonnes of scandium.
A refinery with a stockpile of 20–50 million tonnes could therefore host tens of thousands of tonnes of total REEs and potentially thousands of tonnes of scandium in place. Even partial recovery could create a major Western source of scandium, yttrium, lanthanum, cerium and neodymium. However, composition differs significantly between refineries, and site-specific sampling is essential. The U.S. Geological Survey notes that some bauxite residues contain potentially valuable REEs, while other deposits show only modest enrichment.
Metallurgical Process Streams
A metallurgical facility processing millions of tonnes of material annually may circulate millions of cubic metres of pregnant solutions, leach liquors and intermediate process streams.
For example, a process stream of 5 million cubic metres annually containing 10–100 mg/L of target metals carries approximately 50–500 tonnes of dissolved material per year. Where even 10–20% consists of valuable rare earths, scandium, gallium or other critical metals, one industrial site could generate a meaningful additional product without creating a new mining operation.
The commercial importance is not only the total in-place resource. These elements are already dissolved, transported and concentrated inside an operating plant, potentially eliminating much of the crushing, grinding and primary leaching required for conventional ore.
COAL ASH STOCKPILES
Coal combustion has generated more than 10 billion tonnes of ash stored in landfills and ash ponds worldwide. These legacy deposits typically contain 200–800 ppm total rare earth elements (TREE), with higher concentrations reported in selected basins.
Coal ash commonly contains neodymium (Nd), praseodymium (Pr), dysprosium (Dy), terbium (Tb), yttrium (Y), lanthanum (La), cerium (Ce), samarium (Sm), europium (Eu) and other rare earth elements essential for permanent magnets, electric vehicles, wind turbines, advanced electronics and defense technologies. In addition to REEs, coal ash may also contain economically significant concentrations of scandium (Sc), gallium (Ga), germanium (Ge), vanadium (V) and, in selected deposits, lithium (Li).
Collectively, global coal ash stockpiles represent a potential resource containing millions of tonnes of rare earth oxides, making them one of the world’s largest unconventional critical mineral resources. Recovery of rare earth elements and other critical minerals from coal ash offers the dual benefit of strengthening domestic supply chains while supporting environmental remediation and land reclamation, attracting growing interest across North America, Europe and Asia.
Geothermal Fluids — Indicative Resource Scale
A commercial geothermal operation may circulate several million cubic metres of fluid each year. At a total target-metal concentration of 1–20 mg/L, one facility could contain approximately 5–100 tonnes of dissolved critical minerals annually, depending on fluid chemistry and production rate.
REE concentrations in geothermal fluids are highly site-specific and are often lower than lithium concentrations. Their strategic potential comes from continuous production: unlike a finite stockpile, the fluid is repeatedly produced through existing wells and surface infrastructure. A portfolio of geothermal assets could therefore support continuous modular recovery rather than a single large mining campaign.
Industrial Recycling Streams — Indicative Resource Scale
Permanent magnets are far richer in magnet rare earths than most natural or industrial residues. NdFeB magnets commonly contain roughly 25–35% rare earth elements by weight, primarily neodymium and praseodymium, with smaller quantities of dysprosium and terbium in some applications.
A recycling facility processing 10,000 tonnes of magnet-bearing material annually could therefore receive approximately 2,500–3,500 tonnes of contained rare earths before losses and dilution. At 70% recovery, this could yield around 1,750–2,450 tonnes annually—potentially equivalent to roughly 6–12% of an illustrative 20,000–30,000-tonne future annual magnet-REE shortfall.
Today, less than 1% of rare earths are recycled globally, while end-of-life vehicles, wind turbines, electronics and industrial motors are expected to create a rapidly expanding feedstock base.