Gold Mining Tailings as a Sustainable Secondary Resource: Environmental Impacts, Processing Technologies and Metal Recovery. A Review

Gold mining tailings are increasingly recognized as both a major environmental liability and a potentially valuable secondary resource. This review synthesizes peer-reviewed studies and industrial reports published between 2000 and 2026 to evaluate gold tailings from three interconnected perspectives: mineralogical and geochemical characteristics, environmental and social risks, and processing routes for resource recovery and safer disposal. The literature shows that the behavior of gold tailings is governed by gold occurrence form, liberation size, sulfide content, clay fraction, preg-robbing phases, and site-specific constraints such as water availability and storage stability. Environmental hazards are driven mainly by sulfide oxidation, seepage, runoff, dust dispersion, and residual reagent release, which can affect surface water, groundwater, soils, ecosystems, and human health. On the processing side, the most industrially mature approaches remain gravity concentration, flotation, cyanidation, filtered tailings, and paste backfill, while alternative lixiviants and emerging pretreatment routes show promise but still face challenges related to kinetics, reagent regeneration, scale-up, and cost. By integrating tailings classification with a comparative evaluation of recovery efficiency, environmental burden, energy demand, scalability, and technological maturity, this review provides a decision-oriented framework for selecting suitable retreatment and management strategies. The analysis further suggests that future improvements in gold tailings reprocessing will likely arise from the coordinated application of multiple technological and operational innovations rather than from a single breakthrough technology. Progress will depend on the integration of mineralogical characterization, data-driven process optimization, real-time monitoring, and lifecycle-based sustainability assessment within a comprehensive tailings management framework. This approach can facilitate the transformation of gold tailings from environmental liabilities into valuable secondary resources within circular economy systems.