Tailings are the materials left over after the extraction of valuable minerals from ore. They are stored using several methods based on site-specific conditions, environmental considerations, and safety requirements which include:
- Conventional Tailings Ponds: Tailings mixed with water form a slurry that is pumped into engineered ponds or impoundments contained by earthen dams. These dams can be raised progressively to accommodate increasing tailings volumes. Water decants from the tailings and is often recycled back to the processing plant. This method is widely used but poses risks related to seepage and dam stability.
- Dry Stacking: Tailings are filtered to remove most of the water, creating a dry, stackable material. These tailings are then compacted into stable piles without the need for dams, minimizing water usage and environmental risks.
- Paste Tailings: Tailings are thickened to a paste-like consistency before storage. This reduces water content, helps stabilize the material, and lowers risks of oxidation and seepage.
- In-Pit Storage: Tailings are deposited back into mined-out open pits or underground mine workings, which can reduce environmental footprints and may also help stabilize the pit walls.
- Co-Disposal: Combining fine tailings with coarser waste rock in waste piles can improve stability and reduce environmental impacts(Sankaran, 2025).
When the last ounce of ore is extracted, what’s left behind is an enormous volume of waste. So, how do mining companies safely store billions of tons of this material for decades, if not centuries?
Reference:
Sankaran, M. (2025, January 18). 5 Sustainable Strategies for Managing Tailings Ponds in Mining. KETOS. https://ketos.co/5-sustainable-strategies-for-managing-tailings-ponds-in-mining-operations
