tailings

Tailings are the materials left over after ore has been processed to extract valuable minerals. They typically consist of a fine, water-saturated slurry of ground rock and residual processing reagents, and their composition depends on the ore and the chemicals used in processing. Tailings are usually stored in tailings storage facilities (TSFs), which are embankment or valley-fill structures designed to hold solids and process water. Operations often involve pumping slurry to the TSF and maintaining water cover to minimize dust and control seepage. Closure and post-closure management are common parts of tailings facility planning.

Environmental and safety considerations are central to tailings management. Inadequate containment or deterioration of facilities can lead to contaminated water, acid mine drainage, or release of metals and cyanide used in some processing streams. Tailings dams and impoundments have experienced catastrophic failures, with notable incidents including Mount Polley in Canada (2014), Mariana in Brazil (2015), and Brumadinho in Brazil (2019). These events underscore the importance of robust design, monitoring, maintenance, and independent oversight.

Strategies to mitigate risks include adopting dry-stacking or filtered tailings where feasible, improved monitoring of seepage and structural integrity, water management to reduce stored volumes, and thorough closure planning. Reprocessing tailings to recover remaining metals and using tailings as backfill or construction material are examples of extending value and reducing surface footprint. Globally, tailings management is governed by industry standards, regulatory requirements, and increasingly stringent risk-based practices aimed at protecting water resources, ecosystems, and communities.