The court dismissed MACH Energy’s appeal on Wednesday, with Justices Gordon, Edelman and Beech-Jones finding the state’s Independent Planning Commission had failed its duty to consider conditions cutting emissions “to the greatest extent practicable” as state planning policy requires. The failure concerned scope 3 emissions, released when the coal is burned overseas, which make up about 98 percent of the project’s emissions. The commission had set conditions only on the mine’s own emissions. Chief Justice Gageler and Justice Jagot dissented on that point.
The expansion, approved by the commission in 2022, would double the open-cut mine’s output from the currently permitted 10.5 million tonnes a year to 21 million tonnes and extend operations to 2048 near Muswellbrook in the Hunter Valley. It would allow extraction of an additional 406 million tonnes of coal, generating an estimated 870 million tonnes of carbon dioxide, 98 percent of it as scope 3. The current permission runs out this December. The case now returns to the NSW Land and Environment Court, and the approval remains invalid in the meantime.
The challenge was brought by the Denman Aberdeen Muswellbrook Scone Healthy Environment Group, a local residents’ group that lost in the Land and Environment Court before the NSW Court of Appeal ruled the approval unlawful in July 2025. The High Court ruling is binding across the NSW planning system and directly affects 17 coal proposals currently in the pipeline, with advocates calling it a template for other states and future climate litigation. MACH Energy is owned by MACH Energy Australia, a subsidiary of Indonesia’s Salim Group.