A rural community group is going head-to-head with a mining giant, launching a class action alleging dust from Australia's biggest gold and copper operation has poisoned neighbouring farmland and waterways.
Cadia Community Sustainability Network's lawsuit alleges Newmont's mine, near Orange in central western NSW, has exposed neighbours to a "toxic trifecta" of air, land and water pollution.
Arsenic, heavy metals and PFAS have been found on private properties close to the mine, which the class action alleges are toxic and injurious to human health and the environment.
Nearby landholders and farmers have reported plumes of dust rising from the mine’s tailings facility after a dam wall collapse in 2018.
More recently the community has reported foamy contamination in the Belubula River, which irrigates properties and is a habitat for protected native species.
The legal claim says lab tests have shown the presence of heavy metals and PFAS in the water, allegedly originating from the mine’s ore processing facilities and the tailings dam.
The organisation's lawyer Oliver Gayner said the action group formed after the community was told the dust plumes were steam.
They have since tested rainwater tanks, roofs, dams, bore water, rivers, creeks, their livestock and their own blood for toxins.
"What they found is toxic heavy metals, including arsenic, lead, chromium and nickel at unsafe levels," Mr Gayner told reporters at a property that looks over the mine site at Burnt Yards.
"They found the dust is mechanically crushed and contains crystalline silicon, which is known to be harmful to human lungs."
A statement from Newmont said the company would not comment on specifics as the case was before court, but that it took its obligations seriously and was committed to environmental stewardship.
A 2025 NSW Health investigation found no definitive evidence of health impacts from heavy metal exposure, while recent long-term monitoring has found air quality was "good to fair" and within acceptable limits.
Farmer Frances Retallack said those reports would not withstand legal scrutiny.
"We are not about shutting the mine, we are about forcing change in mining," Ms Retallack said.
"We cannot, as a state, allow this to happen at every mining site that is proposed ... we are on the brink of an absolute disaster."
In 2025, the NSW Land and Environment Court ordered Newmont Mining’s Cadia Holdings to pay more than $400,000 in fines for three dust emissions offences between late 2021 and mid-2023.
The state's Environment Protection Authority entered into an enforceable undertaking with the company in December, dictating it pay more than $300,000 for equipment to support the government’s rural dust monitoring network.
It also had to pay $25,000 for the authority’s investigative and legal costs over two dust emissions incidents in 2022, after a separate prosecution was discontinued.
The locals' class action against Cadia Holdings was filed in the NSW Supreme Court on Monday and is set down for first directions on March 23.
