The impact on the Great Barrier Reef of extending coal-mining operations in NSW - some 1500km away - is the subject of a brewing Federal Court battle.
Environmentalists are challenging a decision by federal minister Tanya Plibersek's office not to take into account the impact of continued mining in the Hunter Valley on the reef, a ruling they say is contrary to law.
A proposal is currently being considered to extend the life of two coal mines in the upper Hunter by up to 25 years under a joint venture between Glencore and Yancoal known as the Hunter Valley Operations Continuation Project.
A delegate for Plibersek, Kate Gowland, ruled in 2023 that the Environment Department was not required to consider potential impacts of the project on the Great Barrier Reef because by her assessment it would not be affected.
Because the project was unlikely to have an impact on the reef, it was not subject to provisions under federal laws.
But in an application to the Federal Court, viewed by AAP on Tuesday, lawyers from the Environmental Defenders Office argued Gowland had failed in her legal duty as delegate for the minister.
The application, made on behalf of the Hunter Environmental Lobby, asked the court to overturn the decision by Plibersek's office and have the matter reconsidered.
The mines' extension would lead to the extraction of up to an extra 400 million tonnes of coal and cause roughly a further 1.15 billion tonnes of greenhouse gases to be released into the atmosphere.
A report by Queensland University of Technology professor Michael Bode that was raised in a submission to the department forecast the resulting emissions would destroy 1000 hectares of reef.
Hunter Valley Operations (HVO) general manager Dave Foster said the issue of the project's impact on the reef and minister's obligations would be for a court to decide.
"There is strong demand for HVO's coal through to 2050 from some of Australia's key trading and security partner nations to ensure their medium term energy security," he said.
"With other mines closing, a need for responsibly mined coal for a number of years to come, and plans to transition our region's economy with equivalent new jobs still in their infancy, HVO's proposal makes sense."
Environmental lobby spokeswoman Jan Davis described the reef as the "canary in the coal mine", saying it will be one of the first ecosystems to collapse as a result of continued burning of fossil fuels.
In 2023, the Federal Court dismissed a similar application brought by the Environment Council of Central Queensland against Plibersek over the consideration of the impact on natural wonders like the Great Barrier Reef from separate coal-mining projects.
A spokeswoman for Plibersek said the minister was unable to comment due to the matter being before the court.