Open Cut » Environment
The Centre for Sustainable Mine Lakes (CSML) was formed in 2002 in response to an urgent need for environmental and social science required for underpinning the closure of open cut mines, and for the identification and evaluation of sustainable beneficial end uses of mine sites following closure.
The mission of CSML is to foster the creation of mine lakes of value to the community, environment and economy through quality research, education and training, and to provide solutions for important mine closure questions that confront mining companies throughout Australia and in many other countries.
CSML’s initial vision was to be nationally and internationally recognised for the quality of its research applied to mine lakes and to contribute to an industry that will, where possible, leave mine lakes that add value to the community. While the initial emphasis of the CSML research and education program was on the sustainable closure of mine lakes, this focus later changed to encompass issues and opportunities relating to the closure of mine sites in general.
The successful Centre of Excellence funding submission to establish CSML was developed in close consultation with the Australian Coal Association Research Program (ACARP). Funding approval for a contribution from ACARP of $150,000pa for three years (later adjusted to four years) was granted in June 2002. This commitment provided support for the establishment of the Centre through contributing to the funding of four projects within the CSML research plan, and to the management and administration of the Centre. The four projects supported by ACARP project C11053 along with an outline of their significant research outcomes follows:
Prediction of long term water quality in acidic mine lakes, with and without remediation (Project 1)
An existing numerical model that had been developed for the prediction of algal blooms in drinking water reservoirs (DYRESM-CAEDYM) was extended to include ecological parameters and applied to the prediction of evolution of water quality of a mine lake in Collie, WA. The model was groundtruthed and found to accurately predict spatial and temporal water quality parameters in the lake. The new model includes user-defined aqueous species, calculation of aqueous speciation, gas phase and mineral equilibrium. Importantly, it also includes descriptions of sediment diagenetic processes. This is a new tool for investigating the impact of suggested mine lake remediation strategies, such as addition of organic carbon and/or nutrients and is now available for analysis of in-lake controls on water quality, particularly pH.
Mine lake remediation strategies (Project 2)
The efficacy of treatment of adverse water quality in old and new acidic mine lakes using biological remediation approaches was trialled in Collie, WA. A conceptual model of the ideal passive remediation system was scoped-out based on the results of the approaches trialled to treat acid mine drainage in the lakes. The system is currently on trial at the City of Stirling’s Spoonbill Lakes which have low pH ~2 waters derived from acid sulphate soil contaminated groundwater. An in-lake remediation trial to clean up toxic and acidic mine water at the Collinsville Coal Project (Xstrata Pty Ltd), North Queensland, using sewage and green waste, has also commenced following the project’s results. Both projects show positive initial results, with the Xstrata initial results leading to Collinsville winning the Ergon Energy Tidy Towns 2006 Award for Environmental Innovation.
Mine lake water quality assessment using bioassays and chemical analyses (Project 3)
Acute and chronic bioassays have been developed using the freshwater microalga Chlorella protothecoides, the rotifer Brachionus calyciflorus and the water flea Daphnia magna and used in a range of applications including the assessment of water quality conditions of mine lakes and a wetland treatment system, the efficacy of treatment methods for remediating acidity and metal contamination in mine lake water, and an analysis of the major causes of adverse water quality in Collie mine lakes.
Construction and evaluation of fluidised limestone bed treatment system (Project 4)
An innovative fluidised limestone reactor (FLR) used to raise the pH of off-take acidified mine lake water from pH 3 to pH 6.5 has been developed and a semi-commercial scale prototype tested at the Griffin mine site. This technology is now being proposed for use in treating acidic leachates at a mine site in Queensland and acid water resulting from acid sulphate soils in WA, as well as producing water that is suitable for aquaculture and horticulture enterprises.