Maximising water recovery and tailings management

Water plays a critical role in critical mining processes such as flotation and leaching, enabling the production of high purity concentrates for marketable products.

However, the quality and availability of water significantly influence both the performance and cost of mining operations.

While some mines use high-salinity water, it can negatively impact recovery rates and require specialised materials to handle the corrosive environment.

For most operations, water availability and cost are pivotal to the viability of a mine, with much of the water used in separation processes ends up in tailings, often stored in wet impoundments, which can pose significant safety and environmental risks if failures occur.

Recovering and recycling process water not only reduces the dependence on fresh water but also minimises water volumes in tailings storage facilities (TSFs).

This enhances TSF safety, bolsters sustainability efforts, and lowers the environmental footprint of mining.

FLSmidth, a global mining technology leader since 1882, provides comprehensive flowsheet solutions for copper, gold, zinc, iron and lithium operations amongst others.

Its offerings include crushing, screening, separation, pumping, dewatering and tailings management technologies.

“We focus on improving tailings and upstream technologies to enhance dewatering and recovery,” FLSmidth’s tailings solutions director Ken Rahal said.

One solution is filtered tailings technology, which extracts water from tailings to achieve solids content of 75-90 per cent or more, enabling significant water reclamation.

This reduces water costs, minimises TSF footprints, and cuts closure expenses at the end of a mine’s life.

FLSmidth’s EcoTails system further combines filtered tailings with waste rock, forming GeoWaste, a stable material suited for dry stacking in seismically active regions.

Thickening innovations also contribute to enhanced water recovery, with FLSmidth’s high-rate, high-density, and Deep Cone thickeners, equipped with spiral rake blades and computational fluid dynamics-optimised feedwells like E-Volute, improve underflow density and reduce short-circuiting effects.

An Australian gold mine partnered with FLSmidth to minimise freshwater usage while maintaining recycled water quality.

Using the E-DUC autodilution system and E-Volute feedwell, the mine increased underflow density by 15 per cent, reduced water to tailings by 46 per cent and achieved 80 per cent water recycling.

“As every site is unique, we work with clients to tailor solutions for optimal water recovery,” Rahal said.