Critical Mineral Recovery from Mine Tailings: A Critical Appraisal of Resource Potential, Processing Constraints and Implications for United States Resource Security
Lawrence Sarpong
New Mexico Institute of Mining and Technology, Socorro, NM, USA.
Abass Aliu *
Department of Environment and Sustainability Sciences, University for Development Studies, Tamale, Ghana.
*Author to whom correspondence should be addressed.
Abstract
Mine tailings are increasingly promoted as an accessible domestic source of critical minerals for the United States, on the argument that legacy and active impoundments already contain comminuted material enriched in elements that earlier processing did not target. This review evaluates the strength of that argument. It examines the geological, mineralogical, metallurgical, economic, environmental and institutional evidence bearing on the recovery of critical minerals from tailings, with particular attention to how well the published record supports claims of near-term contribution to national supply security. Literature was identified through structured searching of open scholarly databases and indexes, supplemented by citation searching and by publications of federal scientific agencies, and was appraised for methodological adequacy rather than aggregated. The evidence indicates that the elemental endowment argument is reasonably secure for a small number of element–deposit pairings, notably tellurium in porphyry copper tailings, germanium in sphalerite-bearing zinc wastes, cobalt in pyrrhotite- and pyrite-rich sulphide tailings, and rare earth elements in coal-related wastes and acid mine drainage precipitates. It is considerably weaker for the broader proposition that tailings constitute a large, readily convertible national reserve. Three constraints recur across the literature. Resource estimation in tailings storage facilities remains poorly standardised, so that reported concentrations frequently cannot be converted into defensible tonnages. Recovery performance is dominated by laboratory-scale results, with few independently replicated pilot demonstrations and fewer still at operating scale. Economic viability depends on cost structures, by-product pricing and residue-management obligations that most published assessments treat only partially. Institutional barriers specific to the United States, including ownership and liability at legacy sites, land status and public acceptance, further separate technical feasibility from realised production. Tailings reprocessing is best understood as a targeted, site-selective supplement to primary supply and remediation policy rather than as a substitute for either. Priorities for future work are identified in resource-scale characterisation, transparent pilot reporting and integrated techno-economic and environmental assessment.
Keywords: Mmine tailings, critical minerals, secondary resources, resource security, tailings reprocessing, geometallurgy, mine waste characterisation, United States