Mine Closure of Pit Lakes as Terminal Sinks: Best Available Practice When Options are Limited?

摘要: In an arid climate, pit lake evaporation rates can exceed influx rates, causing the to function as a hydraulic terminal sink, with water levels in remaining below surrounding groundwater levels. We present case studies from Western Australia for two mines nearing closure. At first site, modelling indicates that waste dump covers potentially acid forming (PAF) material would not be successful over long term (1,000 years or more). The second site is study where PAF management limited by current rock location and suitable cover materials. Pit balance using Goldsim software indicated both lakes sinks if backfilled above long-term equilibrium Poor quality will likely develop evapoconcentration increases contaminant concentrations, providing potential threat local wildlife. Even so, best opportunity limit risk of migration protect regional environments may backfill intentionally produce sink lake.