What are the key risks associated with tailings storage facilities?

Tailings storage facilities (TSFs) are among the largest engineered structures on Earth, yet they remain one of the most critical failure points in the mining industry. Designed to contain the voluminous by-products of mineral extraction, these structures represent a complex intersection of geotechnical engineering, environmental science, and public safety. they pose significant risks to human life, ecosystems, and infrastructure. Let’s explore the various risks associated with mining TSFs.

Geotechnical failure mechanisms

TSF failures commonly result from static or seismic liquefaction, overtopping, and foundation instability. Upstream construction methods show significant associations with static liquefaction (21%) and seismic liquefaction (19%) (Menezes et al., 2025). Static liquefaction, where saturated tailings lose strength suddenly, was responsible for the 2019 Brumadinho disaster in Brazil, which claimed 272 lives (Massignan et al., 2025). Earthquakes represent another critical trigger, with 21% of seismic liquefaction failures occurring in very high seismic risk zones (Menezes et al., 2025).

Climate-exacerbated risks

Climate change intensifies TSF instability through multiple pathways. Increased precipitation and flooding generate seepage and overtopping failures, while extreme temperatures accelerate permafrost degradation in cold regions, weakening structural foundations (Eze et al., 2025). The 2015 Fundão dam failure in Brazil, triggered by intense rainfall, released 60 million cubic meters of tailings, devastating river systems and coastal ecosystems (Lopes et al., 2025).

Environmental contamination

TSF failures release toxic metals including arsenic, lead, copper, and zinc into surrounding environments. Studies in Ecuador documented arsenic, copper, lead, selenium, and zinc exceeding maximum permissible limits across multiple tailings dams, with six of eight facilities presenting severe contamination risk (Salgado-Almeida et al., 2024). Contaminants persist in sediments for years post-failure, serving as long-term pollution reservoirs (Lopes et al., 2025).

Long-term geochemical degradation

Geochemical processes such as sulfide mineral oxidation can alter tailings properties over decades to centuries, increasing permeability and reducing shear strength (MEND, 2025). These time-dependent changes compromise post-closure stability, creating risks that extend far beyond operational periods.

The risks associated with tailings storage facilities are complex, interconnected, and often magnified by time and external environmental pressures. Geotechnical failures, exacerbated by seismic activity and outdated construction methods, continue to claim lives, while climate change introduces new and unpredictable stressors that challenge existing design standards.

References

Eze, K. N., Shorunke, M. O., Ilesanmi, O. O., Anosike, C. U., Ezeanowai, U. H., & Adekunle, O. H. (2025). Sustainability in management for unsaturated mine tailings dams amidst climate change. Discover Geoscience, 3(1), 112. https://doi.org/10.1007/s44288-025-00222-6

Lopes, T. O. M., Silveira, C. R. da, Araujo da Silva, J., Guedes, T., Tavella, R. A., Rola, R. C., Marques, J. A., Vieira, C. E. D., Bianchini, A., & Martins, C. de M. G. (2025). A six-year ecotoxicological assessment of the Doce river and coastal marine areas impacted by the Fundão tailings dam failure, Brazil. Environmental Pollution, 371, 125897. https://doi.org/10.1016/j.envpol.2025.125897

Massignan, R. S., Siqueira-Gay, J., & Sánchez, L. E. (2025). Setting a Comprehensive Bow-Tie Framework for Disaster Risk Analysis of Mine Tailings Storage Facilities. Risk Analysis, 45(12), 4604–4618. https://doi.org/10.1111/risa.70137

MEND | Phase I Summary Report: Geochemical Processes of Geotechnical Significance. (n.d.). Retrieved March 26, 2026, from https://mend-nedem.org/mend-report/phase-i-summary-report-geochemical-processes-of-geotechnical-significance/#exec-summary

Menezes, D. A. de, Matos, J. M. V., Lima, H. M. de, & Santos, T. B. dos. (2025). A data-driven approach linking the credible failure modes for tailings storage facilities risk assessment supported by decision tree assessment. Soils and Rocks, (2). https://www.soilsandrocks.com/sr-2026-011825

Salgado-Almeida, B., Briones-Escalante, A., Falquez-Torres, D., Filián-Haz, K., Guzmán-Martínez, F., Escobar-Segovia, K., Peña-Carpio, E., & Jiménez-Oyola, S. (2024). Assessment of Environmental Pollution and Risks Associated with Tailing Dams in a Historical Gold Mining Area of Ecuador. Resources, 13(8), 105. https://doi.org/10.3390/resources13080105