WaterNSW slams plan for Sydney catchment coal mine

“WaterNSW considers that it is possible that surface water losses could be up to double those that have been assessed [by South32, or] in the order of 6-7 gigalitres a year,” it said.

Loading

The expansion plan has secured support from the Planning Department despite the concerns.

“The department has recommended a comprehensive and precautionary suite of conditions to ensure that, if the project is approved, it complies with contemporary criteria and standards, and to effectively minimise, manage or compensate for any impacts,” a spokesman said, adding it had “thoroughly considered” WaterNSW’s long-standing concerns.

A spokesman for South32 said the company took its “environmental responsibilities seriously and we understand the sensitivities of working within the Metropolitan Special Area”.

“The Dendrobium Mine Extension Project has been designed to minimise impacts on the local environment and we are committed to long-term detailed monitoring and mitigation measures before, during and after mining,” he said, adding “we will not mine beneath dams, named watercourses or key stream features”.

South32 also highlighted the project’s economic benefits, including continued employment of as many as 500 people and $714 million in royalties, taxes and rates.

Peter Turner, a mining projects officer with the National Parks Association, said it was “astounding that Planning has urged approval for this brazenly reckless and greed-driven proposal”, despite knowing water losses would likely be permanent given the difficulty of remediating the mine.

“Planning has recommended approval less than a year after falling reservoir levels triggered fast-track planning for expansion of the [Sydney] desalination plant,” Dr Turner said.

Loading

He also noted that WaterNSW’s assessed losses may be conservative given a 2018 study commissioned by the agency had indicated they could be as much as 24 million litres a day.

“If the proposed mining is approved then the net surface water loss caused by mines in the Special Areas could reach 33 to 38 million litres a day, or 13 to 15 per cent the current capacity of desalination plant,” Dr Turner said.

Peter Dupin, a senior hydrogeologist and former WaterNSW mining manager, said WaterNSW’s estimated water losses were “very conservative” based on that 2018 study.

The likely losses would be “a very substantial additional take to an already monumental cumulative reduction in catchment yields for Sydney’s water supply,” Mr Dupin said in a separate submission.

“The extent and severity of impacts which have occurred in the catchments overlying the Dendrobium Mine are extraordinary,” he said. “To my knowledge there has never previously been a deep underground mine over which all the undermined streams and swamps have almost instantaneously and permanently dried.”

The Independent Planning Commission is expected to give its verdict on the expansion plan on January 22.