Government scientists have raised concerns over a proposed coal mine expansion by Wollongong Coal, stating it could put Sydney’s drinking water at risk.
Wollongong Coal wants to expand its Russell Vale mine under coastal swamps in the Woronora Platea which makes up the upper catchment area and includes several rivers including Woronora, Cataract and Avon rivers.
The company wants to build seven new longwalls and ramp up coal production to three million tonnes per year over a five year period.
But concerns have been raised by the Independent Expert Scientific Committee which said the mine is very likely to have “significant impacts to water resources”.
In a report prepared for the Federal Government, IESC said it found shortcomings in water modelling undertaken by the company, and recommended the mine plan be altered to avoid swamps in the area, ABC reported.
"The final risk assessment underestimated the overall risk to these swamps," the IESC report said.
It said cumulative impacts would work to put the catchments at greater risk.
"The greatest risks of impacts to water are the cumulative impacts from Longwall 6, the Russell Vale Expansion and the additional proposed mining at Wonga West," IESC said.
"The project assessment documentation is not adequate to accurately assess these cumulative impacts."
The government report echoes similar concerns raised in an evaluation of the mine’s effects conducted last year.
It claims the project would result in ‘‘unacceptable damage to crucial environmental assets’’ in the Woronora Plateau, stating it would damage more than a third of the swamps in the plateau.
Gujarat has proposed to monitor the site, but TEC says the only way to ensure to environment stays intact is to ban mining beneath the area.
‘By the time damage has been detected, it is likely that mining will have been completed, with perhaps more swamps being damaged,’’ the report said.
‘‘It should be concluded that the only viable means of preventing damage to [swamps] is to avoid mining beneath them.’’
The mine expansion is currently waiting for a decision from the Department of Planning and Environment, but in the meantime Wollongong Coal has asked the government to approve a plan to mine 400m of Longwall 6 so it can keep production going at the site.
The DPE has recommended the interim expansion be approved, stating its design provided an appropriate buffer from water sources.
"The Department considers that it is unlikely there would be any significant subsidence-related impacts on most nearby key surface features, including Cataract Reservoir."
The Planning Assessment Commission is now tasked with deciding if it will allow the company to access the 400m of coal.
Wollongong Coal said a number of the issues raised by IESC had been resolved in the approvals process.
"Wollongong Coal has been undertaking increasingly intensive study of the Upland Swamps, in its proposed mining areas, for over five years which has provided a strong understanding of the local swamp characteristics including soil profile, surface and groundwater hydrology, ecology and habitat values," the company said.
"A large number of the issues and potential impacts raised by the IESC were raised by, and subsequently resolved with NSW Government regulators as part of the NSW planning process."
The company has previously warned 300 jobs are at risk unless the government approves the temporary fix to its mining plan.