Mining could drain Queensland aquifer

The State’s largest aquifer could be emptied by mining activity, warns a new report.
By AAP and AG Staff September 3, 2010 Reading Time: < 1

A STUDY HAS FOUND Queensland’s largest freshwater aquifer is at serious risk of being drained as a direct result of coal seam gas (CSG) extraction.

The Condamine Alluvium, which extends 3,600 sq. km from Ellangowan to Macalister, north of Dalby, is the main source of fresh water for Dalby, Pittsworth, Millmerran and Macalister and the surrounding farming region.

A report by independent hydrogeologist John Hillier said the aquifer was hydraulically connected to the Walloon coal measures, which the Queensland government is allowing to be dewatered for coal seam gas production.

Falling water levels

The Walloon coal measures are a key supply source for CSG, which at least eight major players plan to turn into liquefied natural gas (LNG) for export. The government has estimated the market for the LNG could reach about 43 million tonnes a year.

Members of farm industry group Central Downs Irrigators, who commissioned the report, are concerned about the impacts of CSG development. John found in his report that water could drain from the Condamine Alluvium alongside falling water levels in the Walloon coal measures following CSG development.

“Because of the very real likelihood of movement of groundwater from the alluvium to the coal measures, more data is required to allow the calculation of the volumes that could be involved,” he says in the report.

The Central Downs Irrigators have called for a moratorium on CSG development in the area, until more work can be done on the environmental impact. Spokesman Johannes Roellgen says irrigators had already seen big cuts in their water allocations in recent years and had cooperated with the government. “But any risk of allowing the alluvium to be drained from the bottom by mining activities is unsustainable and unjust,” he adds.