QUESTIONS have been raised around the sustainability and source of water supplies for the Dolphin Tungsten mine as the population in the surrounding Grassy area grows. In particular there are concerns around long-term planning for water demand and the impact on King Island’s unique platypus habitat in Grassy.
G6M general manager Chas Murcott said the mine uses potable (drinking) water and raw process water. “Potable water needs on site are minimal and restricted to office & ablutions use. Impact on Grassy water supply is expected to be minimal,” Mr Murcott said. “My understanding from discussions with TasWater & Stornoway (TasWater’s on island contractor), is that drinking water supply to G6M residents in Grassy town was factored into the water treatment plant plan and current usage is well below capacity.”
A TasWater spokesperson said the Grassy Water Treatment Plant (WTP) sizing made allowance for future use. “This includes allowing for workers who would move into Grassy,” the spokesperson said. “The WTP serves both Grassy and Currie. “In terms of current water demand compared to capacity, demand has been in line with expectations, noting that it was designed with future growth in both towns considered. Not a lot of the future growth has occurred to date, which means the plant has been operating well within its limitations.”
Mr Murcott said there was no impact on Grassy’s town water supply with independent sources available and Upper Grassy Dam water levels being prioritised over Lower Grassy Dam levels. “Process water needs for the plant and mine are to be sourced primarily via shafts into the old flooded Underground mine. Other sources are recycled tailings water and Lower Grassy Dam top up,” he said.
Since the reopening of the mine, G6M has been working to develop its environmental credentials including putting land under covenant for flora, and fauna protection, initiating a feral cat trapping program around the mine site and Grassy Harbour to protect King Island native wildlife and penguins and is also looking at how to further protect the penguin colonies.
The King Island platypus population is an endemic species that has been isolated from other populations since the last Ice Age about 14,000 years ago. “My understanding is that the Upper Grassy Dam is the main location of the King Island platypus. The dam is responsibility of TasWater and is unaffected by the mine. “G6M has a limited water licence to extract water from Lower Grassy Dam but with the exit weir setup and the company philosophy (operating licences), there will always be a minimal water level maintained in this dam.