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An eight-year research project by Curtin University of Technology and the University of Melbourne has shed light on how areas impacted by mining can be made safe for human use.
Curtin’s Associate Professor Ron Watkins, Director of the WA School of Mines Environmental Inorganic Geochemistry Group (EIGG), said the project undertaken for Stawell Gold Mine, Victoria showed that planting the correct types of vegetation on tailings dams could be an effective way to store mine waste and enable the land to be used productively in future.
Mine tailings ― the fine residue from the processing of ore ― normally occupy the largest area of the mine site.
“Mining is vital to Australia’s future, but we must work to ensure that it is sustainable and that environmental impacts are minimal,” he said.
“Mine tailings frequently contain sulphide minerals that produce acidic drainage if exposed to air and water.
“A standard approach is to isolate tailings by covering them with an impermeable material, such as clay and topsoil, but this can be expensive and severely limits the utility of the land after mine closure.
“Our research has shown that in many cases the impermeable cover is unnecessary and can be replaced by a shallow soil developed directly upon the sulphide-bearing tailings.
“Such an approach can ensure that acid drainage does not develop, while allowing the land to be used for a productive purpose, such as the growing of eucalypt trees for essential oils and firewood and the creation of native seed farms.”
Both of these ideas have been trialled at Stawell in country Victoria.
The Curtin and University of Melbourne team established a research program at Stawell Gold Mine in 2002 to test the viability of the use of shallow covers as a cost-effective means of storing mine tailings and providing economically sustainable end-use for tailings dams.
Curtin EIGG Adjunct Fellow and University of Melbourne Research Fellow, Dr Augustine Doronila, said the project had been successful with the trees growing more than 12 metres in eight years.
“The test site has shown that the tailings dams at many gold mines can be successfully stabilised and revegetated, making them safe for human use,” he said.
“By transpiring away excess moisture, the trees will stabilise the tailings and aid in reducing the formation of acidic drainage.
“This method is a model for how the tailings at Stawell can be dealt with, and is also a model for similar gold mines across Australia and elsewhere in the world.”
The Stawell Gold Mine has been in operation on and off since 1859. During its recent mine life, around 20 million tonnes of waste tailings have been produced which are stored in a tailings dam occupying about 100 hectares at the mine.
The project was commissioned by the operators of Stawell Gold Mine and conducted independently by researchers from Curtin and the University of Melbourne.
Contact:
Associate Professor Ron Watkins; Director; EIGG
Tel: 08 9266 3577; R.Watkins@curtin.edu.au
Dr Augustine Doronila, Adjunct Fellow; EIGG/University of Melbourne
Tel: 03 8344 6813; Email: adoro@unimelb.edu.au
