High Court Blocks a 22-Year Extension of the Mount Pleasant Coal Mine
Australia's High Court has blocked a 22-year coal mine extension after a Hunter Valley community group argued planners ignored emissions from burning the coal overseas.
A Hunter Valley community group won Australia's first climate case in the country's top court
On 7 October 2026 the High Court of Australia dismissed an appeal by MACH Energy and left standing a finding that approval of the Mount Pleasant coal expansion was invalid. The mine is an open-cut pit in the Hunter Valley, north of Sydney. MACH wanted to keep it running until 2048 — 22 years past the current end date — and to extract an additional 406 million tons of coal. The Guardian reported the expansion would have doubled output to 21 million tonnes a year.
The case was brought by the Denman Aberdeen Muswellbrook Scone Healthy Environment Group. Wendy Wales, a retired science teacher and the group's president, has described it as a refusal to pretend that coal burned overseas has nothing to do with droughts, fires and floods at home. Positive News also named retired teacher Tony Lonergan among the people who took the fight on after state planners approved the project in 2022.
Scope 3 emissions — the gases from burning the exported coal — were 98 percent of the project's predicted greenhouse gases. The Independent Planning Commission did not impose conditions aimed at minimising those emissions. A majority of the High Court held that the commission was required, under clause 2.20 of the state's resources planning policy, to consider conditions that would minimise greenhouse gas emissions to the greatest extent practicable, and that it had not done so. The court was split. The Guardian reported a 3-2 decision. It is the first climate case Australia's highest court has decided.
Lead lawyer Anita O'Hart said the ruling will be applied by courts and planning authorities across Australia. MACH Energy said it accepts the decision and will keep pursuing options to continue the operation. The current approval still runs toward December 2026. This is not a permanent lock on the pit. It is a ruling that the last approval was unlawful because the climate conditions were never properly considered.
Key Facts
- Judgment: 7 October 2026, [2026] HCA 35
- Extension sought: to 2048, about 22 years, plus 406 million additional tons
- Reported expanded output: 21 million tonnes a year
- Scope 3 share of project emissions: 98 percent
- First climate case decided by the High Court of Australia
- Community plaintiff: Denman Aberdeen Muswellbrook Scone Healthy Environment Group
- Sources: High Court judgment summary, Reuters, The Guardian
Why This Matters
Most climate arguments stall on pledges. This one turned on a statutory duty planners already had: consider how to cut emissions as far as practicable, including the coal the buyer burns. A small residents' group forced that duty into the country's top court. If the precedent holds, the next fossil-fuel application in New South Wales cannot wave away overseas combustion as someone else's problem.
What We Don't Know Yet
- Whether MACH can win a fresh approval that does consider scope 3 conditions
- How other Australian states will treat a New South Wales planning clause
- Whether the mine stops in December 2026 or finds another lawful path
- The judgment does not ban coal. It invalidates this approval