Recent legal successes most notably last month's recommendation in the Queensland Land Court against the approval of Clive Palmer's proposal for a $6.5 billion thermal coal mine in the Galilee Basin in Central Queensland is but one example of the mounting legal challenges to coal and gas projects being developed or expanded.

Traditional owners have also mounted a number of legal challenges against these developments.

Given this background, an Upper Hunter environment group has commenced legal action to stop a massive expansion of Mount Pleasant coal mine near Muswellbrook.

The expansion, approved by the NSW Independent Planning Commission (IPC) in September would make Mount Pleasant the biggest open-cut coal mine in NSW and poses a serious threat to human health, biodiversity and the climate.

Denman Aberdeen Muswellbrook Scone Healthy Environment Group (DAMSHEG) is a local community organisation concerned about the environmental, social and economic impacts of continuing and prolonging coal mining in the Upper Hunter.

"Muswellbrook already has the worst air quality in NSW," DAMSHEG President Wendy Wales said. "Allowing Mount Pleasant to become the biggest open-cut coal mine in the state, directly upwind of town, is only going to make this dangerous health problem worse.

"It's not just the health impacts - this project is wrong on so many levels. Mach Energy is planning to dig up 444Mt of coal that will add more than 870 million tonnes of CO2 to the atmosphere.

"We simply can't afford to do that - climate change is already running away on us. Surely, we have learned something from the catastrophic heatwaves, droughts, fires and floods in recent years, here and across the world.

"Scientists recently found a new species of lizard on the project site - the Hunter Valley Delma. The mine expansion could push this unique animal to extinction before we have even learnt anything about it. The Muswellbrook region and the Liverpool, Plains are its only known habitat.

"Any way you look at it, this project is a bad idea. We think the Independent Planning Commission made a serious mistake when it approved this mine expansion, so we are taking the matter to the Land and Environment Court."

DAMSHEG is being represented by the Environmental Defenders Office.

EDO Managing Lawyer Kirsty Ruddock said: "DAMSHEG will argue that the IPC made errors in failing to consider the impacts of the scope 3 emissions from the mine on the environment and social and economic impacts in the local area including on air quality.

"The group is arguing the commission failed to consider the impacts of the scope 3 emissions from the project on the world's carbon budget."

Mount Pleasant coal mine is also subject to a S10 application under the Federal Aboriginal and Torres Strait Islander Heritage Protection Act 1984 made by the Plains Clan of the Wonnarua People (PCWP) following the the IPC decision to approve the expansion plans.

PCWP spokesman Scott Franks said the IPC has approved a mine expansion covering land we know is home to 3500 cultural sites.

A similar claim made by the PCWP in 2020 covering the Ravensworth Estate is still awaiting a decision from the Federal Minister for Environment Tanya Plibersek.

The Federal Minister Tanya Plibersek has also been asked to reassess a number of fossil fuel approvals including Mount Pleasant.

The action relies on a provision of the Environment Protection and Biodiversity Conservation Act, section 78A, which allows a person to request the minister reconsider a decision on a project when a "matter of national environmental significance" is set as a "controlling provision".