High Court blocks the Mount Pleasant coal extension and counts the overseas burn

Australia's High Court on Wednesday dismissed MACH Energy's appeal and left in place a decision blocking a two-decade extension of the Mount Pleasant coal mine in the Hunter Valley. The mine is due to stop digging in December. The company wanted to run it until 2048 and to double output, which would have meant another 406 million tons of coal. The court ordered the company to pay costs. It is the first climate case the High Court has decided.

The legal point is narrower than the headline. New South Wales' Independent Planning Commission approved a path for the project in 2022 that the Denman Aberdeen Muswellbrook Scone Healthy Environment Group later challenged. The commission, the court found, had failed to consider conditions that would cut the project's greenhouse gases as far as practicable. Justice James Edelman put the arithmetic in the reasons: scope 3 emissions, the coal burned by customers after it leaves the site, made up 98 percent of the project's greenhouse gases. The commission had focused on the 2 percent produced at the mine and had not dealt with the rest.

That split is the part other fossil-fuel files in New South Wales will have to read. Scope 1 and 2 are the diesel, the electricity and the methane at the pit. Scope 3 is the coal in a boiler in Japan, South Korea or somewhere else, which is where almost all of the carbon from an export mine sits. Planning law in the state has often treated that burn as someone else's ledger. Edelman's line removes that comfort for this class of decision. A consent authority that writes reasons about 2 percent, and is silent on conditions for the 98, has not done the job the statute asked of it.

MACH Energy's commercial problem is the December clock. Without the extension, Mount Pleasant stops when the current consent ends. An extra 406 million tons is not a marginal seam. It is a second life for the pit, and it is the volume the company took to the High Court. The dismissal with costs ends that appeal. It does not, by itself, rewrite every coal consent in the Hunter. It tells the Independent Planning Commission, and any court below it, that a reason which ignores the overseas burn is open to challenge.

Wendy Wales, a retired science teacher and president of the community group, said after the ruling that the court had rejected the idea that coal could be dug, shipped and burned with the consequences treated as someone else's. Anita O'Hart, for the group's side, called it a historic ruling in Australian environmental law and said planning authorities could not ignore the chain from a project's emissions to local climate harm. Both statements are advocacy. The binding text is Edelman's: the commission failed, in its reasons, to consider conditions that would minimise emissions to the greatest extent practicable, because it looked only at 2 percent.

The mine sits northwest of Sydney, in a valley that already has a long wall of open-cut coal. Ravensworth and the other Hunter pits are the physical context. Mount Pleasant's extension would have added, on the community group's account carried by ABC, roughly twice Australia's annual greenhouse-gas total once the coal was burned. That comparison depends on how the national inventory is counted, and it is an advocate's framing of scope 3. The court did not need that comparison. It needed the 98-to-2 split, and it used it.

What happens next is a consent problem, not a new mine plan. The commission can be asked to decide again, this time with reasons that actually address the overseas burn and any condition that might limit it. A condition that bites on scope 3 is hard to draft: the miner does not own the boiler. The court has not told the commission to refuse coal. It has told it that a file which pretends the coal is not burned is not a lawful file. For MACH Energy, December is close, and the appeal route to the High Court is now closed.