In June 2025, Rix's Creek Mine reported a discharge from an uncapped borehole, that was part of a drilling program to better understand the depth of old mines and improve seepage management.
The discharged water flowed overland into a dam and then into Stonequarry Gully, which runs into a tributary of the Hunter River. A submersible pump, normally used to return seepage water from the dam to the mine's water management system, was not operating at the time.
EPA Director Operations, David Gathercole, said the incident could have been avoided with better management.
"Operators are required to have strong systems in place to appropriately manage salty water and avoid pollution incidents," Mr Gathercole said.
"When plant equipment is not operated in a proper and efficient manner, the risk of pollution increases, and unnecessary pressure is placed on the surrounding environment.
"Groundwater from underground coal mining is high in salt and when it enters waterways it can disrupt fish migration and impact aquatic health.
"Even though no serious harm was detected downstream of Stonequarry Gully, the region's waterways were already stressed following severe weather, and poor management only makes matters worse."
Following the incident, Rix's Creek capped the borehole and reinstated operation of the pump to reduce the likelihood of recurrence.
