Document Type

Journal Article

Faculty

Faculty of Health, Engineering and Science

School

School of Natural Sciences/Mine Water and Environment Research Centre

RAS ID

16275

Comments

This article was originally published as: Mccullough, C. D., Marchand, G., & Unseld, J. (2013). Mine closure of pit lakes as terminal sinks: best available practice when options are limited?. Mine Water and the Environment, 32(4), 302-313. The final publication is available at Springer via here

Abstract

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

Access Rights

free_to_read

Share

 
COinS