Challenge: Hypersaline groundwater in mining regions 

 

Hypersaline groundwater is a ubiquitous feature of the hydrologic setting in many inland regions, and is commonly used in mining and mineral processing operations, generating saline waste streams with site-specific management challenges, including:

 

• Brine effluent, some pre-treated for water recovery and volume reduction but mostly discharged into the dams of tailings storage facilities

• Neutralised brine streams from ore acid leaching circuits, some pre-concentrated in evaporation ponds for volume reduction at significant capital outlay (due to low evaporation rates), but mostly discharged into the dams of tailings storage facilities.

• Hypersaline groundwater inflow to underground mines that is pumped and stored in unused mine pits, but with increasing salinity, eventually requires conventional management approaches such as managed aquifer recharge, discharge to salt pans, or evaporative volume reduction in large evaporation ponds, all of which are costly and increasingly being considered unsustainable.

• Reject brine from coastal desalination plants, operated by miners for freshwater supply, the bulk of which is presently discharged to the ocean with minor or no pre-treatment.