Engineered flow-through closure of an acid pit lake: A case study
Mine Closure 2015 Proceedings
School of Science / Centre for Ecosystem Management
The Lake Kepwari flow-through trial has monitored both lake and river ecology and water quality for two years flow-through, plus one year post-breach monitoring (2012). The flow-through trial involved both the development of a management plan and application of the appropriate licensing framework through the Department of Water state regulatory agency via an operating strategy document. The aim of this document was to establish the suitability of flow-through as a closure strategy. The key conclusion of the three-year flow-through trial is that that social and environmental risk and benefit to the Collie River South Branch (CRSB) and Lake Kepwari are best managed using flow-through as a closure strategy. Lake water quality has been significantly improved through nutrient addition and acidity neutralisation. Improved water quality, particularly in terms of elevated pH and reduced metal/metalloid concentrations, has now significantly reduced the socio-environmental risk of closure of this landform.