Conservation groups are calling for a moratorium on a swarm of Centennial Coal proposals that would reintroduce mine waste discharges to the upper Coxs River catchment as current management is overwhelmed. You can help by writing a short e-letter to Premier Chris Minns.
A strategic approach to Centennial Coal’s and Energy Australia’s proposals in the Gardens of Stone region is required to protect the public interest in drinking water and the environment. Previous efforts to stop pollution have greatly improved the outcome.
Unstable waste management
Centennial Coal’s Springvale mine is joined at the hip to Energy Australia’s Mt Piper Power Station near Lithgow. Not only does Springvale supply coal, both it, and its Angus Place sister mine, supply gigalitres of coolant water.
As this plant’s baseload power supply has declined with green energy reform, this mutualistic relationship has become unstable. Centennial now produces vastly more mine wastewater than the power plant needs, and Centennial’s solution is to discharge increasing volumes of wastewater into Sydney’s water supply.
Sydney has some of the best drinking water in the World, and the platypus in the World Heritage Area also need clean water to find food with its electrosensitive beak. The Department of Planning, however, believes that a salinity 940EC is suitable, as an upper limit for drinking water discharges. This awful standard is twice as salty as Adelaide’s water taken from the Murray River.
Centennial claims a beneficial environmental outcome because the Coxs River headwaters are badly impacted by salt leaching from the Mt Piper ash emplacement. The salt in the emplacement is from a water treatment plant that was supposed to stop this pollution, but salt is leaking into the waterway. This incompetent waste management is Centennial’s excuse for more pollution. Mine water discharges must be cleansed to a condition equivalent to the streams that once flowed off Newnes Plateau at a salinity level of 30EC. Energy Australia must stop the leakage of mineral salts from the Mt Piper waste emplacement. The required waste management is part of cost of coal-fired power, as the polluter must pay. If the industry can’t ensure Sydney enjoys some of the best drinking water in the world, it has no social licence.
More waste
Through March 2025 Centennial Coal and Energy Australia discharged 18.5ML/day of partially treated mine waste into Sydney’s drinking water supplies without a pollution licence from the EPA. The Independent Planning Commission (IPC) then approved a temporary transfer of polluted water to a dam that discharges into Sydney’s drinking water supply. This administrative band-aid enables the 30-year-old Piper power plant to be patched up during a two-month shut down, but these repairs won’t solve the waste management problem.
Past reactive decision making led to many gigalitres of mine waste being stored in the Angus Place mine. Centennial wants to pump out that waste and restart the mine. So, in addition to 42ML/day of mine waste problem Centennial and EnergyAustralia have now, they proposed to add another 10ML/day. That’s a waste flow of over 50ML/day, greater than that of upper Coxs River, to give a comparison.
Centennial’s solution is to send it down river, but this plan of diluted mine waste is not a palatable solution. Angus Place mine should instead be rehabilitated and let its gigalitres of waste rest in peace.