Menangle Sand and Soil Ltd has been fined $15,000 after overflow from a dam that holds turbid or muddy water allegedly discharged into the Nepean River.
The NSW Environment Protection Authority (EPA) fined the quarry after the pollution was discovered.
The quarry on Menangle Road holds an Environment Protection Licence to operate sand and soil extraction which involves the 'washing' of the extracted sand, however the licence does not permit the discharge of any muddy water.
The EPA alleges that turbid water was discharged from a dam at the quarry into the Nepean River, near the Menangle Road river crossing, between June 3 and 5 this year.
EPA director of regulatory operations Giselle Howard said that while the environmental risk was assessed as low, the quarry was not licenced to discharge any turbid water.
"EPA inspections on June 5 did not identify any obvious impact to aquatic life but there may have been short term impacts in localised parts of the river from the alleged pollution," she said.
"The quarry operator has admitted the incident and said it was caused by a communication breakdown which left a pump running, allowing a dam to overfill, which discharged into the Nepean River.
"The quarry has now installed enhanced technology to prevent any recurrence, including a new pumping procedure, a dam level indicator and electrical float switch."
Penalty notices are one of a number of tools the EPA can use to achieve environmental compliance including formal warnings, official cautions, licence conditions, notices and directions and prosecutions.
In this instance the EPA issued a penalty notice. The notice recipient may pay the penalty notice, seek a review or elect to have the matter determined by a court.
For more information about the EPA's regulatory tools, visit: www.epa.nsw.gov.au/legislation/prosguid.htm.
The Advertiser has reached out to the Menangle Quarry for comment.