Protecting Wilderness and National Parks

Miner risks cutting key water supply artery

“The recent approval to mine coal under the fragile gravity fed Upper Canal[1] places this critical water supply infrastructure at risk of damage and being shut down,” said Keith Muir, director of the Colong Foundation for Wilderness.

“The Upper Canal provides 20 per cent of Sydney's water and connects Broughtons Pass Weir on the Cataract River with Prospect Reservoir 64 kilometers away.  When completed in 1888 it was considered an engineering marvel because it can supply 680 megalitres of water a day using the force of gravity alone”, Mr Muir said.

“The Upper Canal went off line for some months to repair damage due to longwall mining within the tunnel connecting it with the Broughton's Pass Weir.  More interruptions to this water supply can be expected when the open canal section is mined,” he said. 

“Closing down this key artery limits the flexibility of the entire system to cope with other problems, such as blue-green algae outbreaks, or mechanical failures elsewhere” he said.

“As you can imagine, when the canal drops by over one metre due to coal mining directly underneath it, the slope of the canal bed will be altered.  The metal aqueduct over Simpsons Creek and the nearby sandstone culvert will be damaged by the surface subsidence, said Mr Muir.

“Water flows in the canal will need to be suspended while the canal is rebuilt to its original grade, if that is possible.  The promises by miners to repair damage are often not adequately delivered but this time failure and delays in repairs are more serious”, he said.

“BHP-Billiton received approval to mine last month and has put the security of Sydney's water supplies for its coal supply.  If something goes wrong while the Upper Canal is off line, then Sydney will learn in a drastic way why it is always better to avoid risk when the potential consequences of damage are high”, said Mr Muir.

[1] BHP Billition media release Illawarra Coal's longwall 409 approved 23 November 2007

For more information contact: Keith Muir, (02) 9261 2400 (wk) or 9550 3615 (ah)