Mining may harm Illawarra's water supply BY BEN CUBBY 10/06/2009 10:11:00 AM The region's drinking water supply in and around the historic Cataract Reservoir is about to be undercut by multi-storey longwall coal mines in a case that will test the NSW Government's willingness to apply its own environmental guidelines.
Packed beneath the pristine reservoir, near Appin, lie tens of millions of tonnes of high-quality coking coal, greatly desired by the Indian steel industry.
Ambitious new plans submitted to the Government from mining corporation, Gujarat NRE, would intensify mining in the area for decades to come, tripling the mine's output.
But cutting out the coal would cause the drinking water catchment, which supplies Sydney and the Illawarra, to crack and tilt due to subsidence, with unknown though almost certainly negative impacts on the water supply.
Government sources said it had no choice but to try to rein in the company in the face of clear evidence of potential damage to the water catchment area.
As well as foreshadowing damage to waterways, the company's intial proposal also conceded that there was a "high level of risk" to Telstra fibre optic cables, electricity and water pipelines and roads in the area.
The company said it was working out what level of environmental damage could be tolerated after being told by the Director-General of the Planning Department that it would take into account recommedations of a landmark inquiry into coal mining.
The independent southern coalfields inquiry last year found that mining was causing serious damage in the water catchment, and the Government should require a reverse onus of proof on companies seeking to mine in sensitive areas.
Longwall mining, in which broad panels of coal a few metres high and hundreds of metres long are bored from the earth, causes ground above to subside. In other examples of multi-level mines in NSW, surfaces above dropped and tilted by as much as 5m in places such as Newstan Colliery near Lake Macquarie.
Gujarat NRE's head of technical services said there was no evidence yet that earlier mining beneath the dam had led to cracking and loss of water, though there could be an element of undetected "microcracking".
"If there will be subsidence of a nature that would cause catastrophic damage to a significant surface feature, then we would consider not extracting that and sterilising coal," said Chris Harvey, Gujarat's head of technical services.
"It's horses for courses - we can't give an exact level (of subsidence) because it depends on the assessment of each surface feature," he said.
Gujarat NRE has hired consultants to prepare a new report on the environmental impacts of the mine expansion.
A spokesman for the planning department said inquiry findings would "form a key part of the department's assessment of these projects."
Environment groups and the NSW Opposition believe that mining under the drinking water supply should be stopped or more closely controlled.
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