A mine contractor was fined $15,000 for a pollution incident while working on South32's Appin coal operation in April, the Environment Protection Authority has said.
Abergeldie Contractors Pty Ltd, a civil engineer based in St Marys in western Sydney, was working on the mine's ventilation and acces improvement project.
The contractor had built a sediment basin to help manage discharge into the environment but when a "dewatering pump" was left unattended, muddy water was pumped into Foot Onslow Creek, which flows into the Neapean River near Menangle.
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The EPA said a silt boom was deployed and muddy deposits were seen about 50m downstream.
While the incident happened in April the EPA only revealed it this week. It said this was because when the incident occurred there was no risk to human health and there was a small contained risk to the environment.
"Clean-up actions by the mine were taken in a timely and responsible manner," the EPA said.
The incident did not happen in the drinking water catchment.
NSW EPA director Adam Gilligan said the EPA expects construction sites to be properly managed to protect the local environments and waterways.
"We have issued a fine for an alleged discharge of turbid water and mud from Endeavour Coal's Appin Mine Ventilation and Access Project to a nearby creek," he said.
"The continued pumping meant mud at the base of the pond was pumped into Foot Onslow Creek.
"The EPA oversaw an effective clean-up operation in the impacted part of the Creek with minimal environmental impact.
"This serves as a reminder to businesses to ensure that works that could impact on the environment are supervised closely to prevent pollution and that appropriate environmental controls are in place."
To report a water pollution incident, contact the EPA Environment Line on 131 555.
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