Mine Pit Lakes – Their Characterisation, Assessment, Management and Value as Potential Lead Indicators for In-Situ Metal Recovery Opportunities

The Challenge

Mine closure requires assessment and management of the pit lakes that can form in open pit mines after mining ceases. Understanding of the long-term environmental risk posed by these lakes is incomplete, which often hampers the realisation of post-mining reuse opportunities.

Key Findings

Mine pit lake waters continue to evolve for many years after mine closure, posing a significant challenge to the regulation and management of mining legacy sites.

Groundwater chemistry represents the primary control on pit lake water quality at equilibrium, particularly in regards to major ion content, pH, and water salinity.

pH represents a significant influence on metal solubility in lake waters, with mine pit lakes in some sites reaching concentrations compatible with in-situ metal recovery.

Proposed Benefits to WA

This research will help address the environmental legacy of mining in WA and support better planning of, and a reduced environmental footprint for future WA mines. The data generated will assist government and industry in better defining the residual risks of existing pit lakes, and identify opportunities for beneficial post-closure uses.

Keywords: Mine pit lakes, water quality, in-situ recovery, mine closure