Not enough known on CSG: experts

Queensland Country Life
8 Jan 2011

FEDERAL and State water experts are backing calls by landholders for an urgent study of the potential impacts of coal seam gas (CSG) development on the nation’s water resources.

The focus is largely on the potential $35 billion industry in south-east Queensland, where up to 40,000 wells could dot the Surat and Bowen Basins over the next 20 years – and where there have already been water contamination incidents.

Last month, Arrow Energy confirmed benzene, toluene, ethylene and xylene – together known as BTEX – had been found in wells at a Bowen Basin gas site.

In October, BTEX was discovered in eight wells at drill sites run by Origin Energy about 300 kilometres west of Brisbane, while earlier this year a coal gas project near Kingaroy was shut down when benzene and toluene were detected.

While 95 per cent of known reserves are in Queensland, increasing exploration in NSW by companies, including Santos and Metgasco, is expected to uncover more reserves.

Companies are testing for CSG using hydraulic fracturing, known as “fracking”.

Rules regulating this practice, which involves injecting a mix of water, sand and chemicals underground to force gas to the surface, are not clear cut, as specific approval for fracking is not required.

NSW Natural Resources Commissioner, John Williams, has warned there could be potentially catastrophic impacts on State water resources if CSG projects go ahead unchecked.

He supported a call by National Water Commissioner, Chloe Munroe, for a precautionary approach.

The National Water Commission released a position paper earlier this month identifying a variety of risks, saying cumulative impacts were not well understood, and that there could be “substantial consequences”.

“If not adequately managed and regulated, the industry risks significant, long-term and adverse impacts on surface and ground-water systems,” Ms Munroe said.

She said mining should operate under the same rules applied to other water users.

Dr Williams said it was vital that mining and natural resources were integrated before mining activity occurred.

“We need a plan of action to minimise harm to water resources if coal seam gas extraction takes place,” he said.

“We do need to mine, but we need to know where we can do it without harming natural resources, and the best time to do this work is before the development happens so the community knows where it can be harvested without damaging their future and the mining industry has some security.”

He said legislation, including the Mining Act, needed to be brought into line with sustainable development principles.

Dr Williams, a member of the Wentworth Group, said taking CSG should not interfere with the viability of water resources and agricultural land, but there was no process yet to prevent this.

Ms Munroe’s report said extracting large volumes of low-quality water would have an impact on connected surface and groundwater systems.

Dramatic depressurisation of coal seams could reduce pressure to nearby aquifers, reducing flows and causing land subsidence.

A report by JP Morgan said the coal gas seam industry had significant water risks, including a reduction in the water supply to towns and landowners, reduced quality, gas migration to water bores and the safe storage of salt.

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