South32 up for environment award for fault line water drainage work

The company's subsidiary Illawarra Metallurgical Coal is one of two finalists in the environmental category at the NSW Minerals Council's health, safety, environment and community awards.

It was nominated for research into the Eloura fault line, to analyse its behaviour and determine how it may contribute to risks to the water catchment.

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In particular, the studies have sought to find out if the fault line posed a risk of "connectivity" from the Avon Dam - that is, a gap that the dam could drain through into the mine and beyond.

The Elouera Fault zone is located south of Dendrobium's recent Area 3B, between the completed Longwall 18 and the old Elouera mine (now known was Wongawilli mine and owned by Wollongong Resources).

The study found the fault is unlikely to cause significant risk to the water supply.

"Given its proximity to Lake Avon, a vital drinking water source for the Macarthur and Illawarra region, understanding the fault's nature and potential risks to the water supply was crucial," states the award citation.

"Various methods were employed, including packer testing, downhole geophysics, pumping tests, and sampling at different depths. Tracer testing using salt and fluorescein dye was also conducted, revealing differing hydrogeological conditions at the sites."

The results indicated the fault was unlikely to cause connectivity or risk draining the dam into the mine.

"By improving the understanding of the fault's hydrogeological behaviour, the investigation enhanced confidence in managing potential impacts on the water supply associated with mining operations," the citation said.

"The use of tracers provided valuable insights into fault connectivity and transmissivity, contributing to a comprehensive understanding of potential risks."

Company documents say Elouera is a complex fault comprising three distinct but structurally connected fault zones.

The fault zone is unlikely to be related to the water loss for which IMC has to pay $2.9 million, as it is slightly south of the most recently mined longwall, number 18.

The payment will go towards funding a waterway restoration project in the area. It was agreed on between IMC and the NRAR some years after a complaint was made that the mine had been draining water without a licence over the past five years.

A new regime has now come in which will allow the miner to be licenced to take water in this manner, for a fee, and South32 has lodged an application.