The New South Wales government ignored warnings from its own independent panel that there was insufficient data to approve the expansion of the Dendrobium coalmine near Wollongong,

The government is under fire for approving extra longwalls at the mine without waiting for the panel to complete a much broader study of the impact of mining under Sydney’s water catchment.

Mining had been conditionally approved in 2008, but further regulatory hurdles were placed on the company because of concerns from WaterNSW.

These included establishing a panel of experts to advise the government on specific mining proposals as well as the broader environmental impacts of continued mining near Sydney’s dams.

It now appears the government ignored the advice from the panel on Dendrobium. The advice was released on Monday, following a report in the Sydney Morning Herald saying the new longwalls had been given the green light.

The April advice of just two pages, says: “Longwall 14 should not proceed without confirmation that the expanded monitoring network is being implemented. ... Longwall 15 should not proceed without resubmission of plans reflecting the expanded monitoring network.”

The panel was particularly concerned that the company had not yet submitted the data and monitoring on longwall 13, which would give a clearer picture on subsidence and its impacts.

The government made the decision before the release of another two reports – one on the Dendrobrium mine due on Tuesday and another due later this year, which will explore all the environmental risks and the cumulative impact of multiple mines undercutting the Sydney catchment. A spokesman for the NSW minister for planning, Anthony Roberts, said neither had yet been received.

The mining spokesman for NSW Greens, Jeremy Buckingham, said the government had ignored the “neutral or beneficial test for development in the catchment” because of its addiction to coal.

“We should not be putting a handful of potential jobs ahead of the safety and security of the drinking water for millions of people in Sydney,” he said.

Longwall mining involves digging huge parallel corridors underground along the seam of coal, using a giant excavator that holds up the ceiling above as it works.

As the coal is excavated and the machine moves along the face of the seam, the ceiling of the corridor collapses behind, causing subsidence and potentially fracturing of rock layers that can lead to surface water escaping into the mine below.

WaterNSW, which manages Sydney’s dams, sounded the alarm about mining under the catchments and close to Sydney’s dams earlier this year, after a study of the Dendrobium mine revealed greater impacts from cracking than forecast by the company.



“From WaterNSW’s viewpoint, the single most important consequence ... is that subsidence induced by the Dendrobium mine longwalls is likely to be resulting in significant diversion of surface water which would otherwise contribute to greater Sydney’s water supply,” Water NSW warned earlier this year in a submission.

It also warned of environmental degradation and damage to creeks and swamps. A spokesman for WaterNSW said the agency was somewhat reassured by the additional conditions imposed by the planning department in May, when it approved longwall 16, including improved monitoring of long-term groundwater impacts and more comprehensive reporting of outcomes that approach or exceed predicted thresholds.

“WaterNSW acknowledges recent reforms implemented by the NSW government in line with actions advocated by WaterNSW. This includes a review of subsidence and groundwater analysis used to predict rock-fracturing resulting from longwall mining, and the establishment earlier this year of an independent expert panel to review mining activity proposals.”

“WaterNSW is working with the panel to better understand the extent and nature of impacts which have already occurred at Dendrobium mine, and the risks posed by Longwall 16 and future panels.

A spokesman for South 32, which owns the Dendrobium mine, said the company took its environmental responsibilities seriously.

“We can confirm that world-leading experts on the independent expert panel on mining in Sydney’s drinking water catchment provided their independent examination and assessment of the Dendrobium longwall 16 management plan prior to its endorsement.”

The panel actually said: “Based on the information available to it, the panel does not have any evidence at this stage relating to loss of water that constitutes an exceedance of of the development consent.”

“Based on the information currently available to it, the panel is not in a position to reach a confident conclusion [on future compliance].”

South 32 has applied for planning approval to extend its Dendrobium mine to the north and west to extract at least 40m tonnes of coal and extend mine operations until 2048.

Also in the planning process is a major expansion of Xtrata’s Tahmoor Colliery. Gujarat NRE’s expansion of the Russell Vale mine, near Wollongong, is still on the books. Endeavour Mining has now applied for an exploration licence near Douglas Park, near Campbelltown.e.