Dendrobium coal mine expansion opposite by WaterNSW over drinking water problems in Sydney

Written by Javed Iqbal

The government body tasked with protecting NSW’s drinking water has opposed a coal mine expansion, which it claims threatens Sydney’s second-largest dam.

The NSW Department of Planning is considering a revised plan to expand the Dendrobium coal mine, which was declared State Significant Infrastructure (SSI) in the wake of its rejection by the Independent Planning Commission (IPC).

WaterNSW objected to the original proposal because of its impact on the water supply. The Agency maintained its opposition in its most recent submission on the Environmental Impact Assessment (EIS) of the revised plan.

“The submitted proposal is considered unacceptable to WaterNSW in its current form due to impacts on water volume, water quality and ecological integrity within the special area of ​​the metropolitan area,” it states.

In its latest post, WaterNSW revealed that the mine expansion posed a risk to the stability of Avon Dam, the main water source in the Illawarra region.

“WaterNSW, as owner and operator of the dam, is very concerned that the safety of the dam may be compromised by the proposed long-wall mining operation.

“The differential motion on the dam walls can cause cracks to open in the dam walls.”

The agency said subsidence from longwall mining at the dam was expected to be between 35 and 40 millimeters.

This is eight times higher than the subsidence observed by continuous monitoring from 1970 to 2021.

Graph of mine plan showing reduced longwall activity
WaterNSW says despite the smaller mine plan that the project will still lead to ‘significant’ water losses.(Delivered: South32)

WaterNSW claimed that the impact of longwall mining on the dam had not been assessed by an appropriately qualified dam engineer and the sinking effects in the EIS were “greatly underestimated”.

Debate on the extent of water loss in water

WaterNSW said that despite a 60 percent reduction in the mine footprint, work on the proposed underground mine will still result in the removal of 70 gigaliters of water over the next 17 years.

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Javed Iqbal

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