After more than a decade of legal challenges and applications, New Hope Group's New Acland water licence approvals for the mine expansion were finally endorsed by the Department of Regional Development, Manufacturing and Water in March.

Environmental group Oakey Coal Action Alliance this week lodged a fresh challenge in the Queensland Land Court, only a fortnight after the mine was officially opened.

OCAA has also sought undertakings that New Acland Coal cease carrying out operations, including the mining of coal, pending the outcome of the appeal.

"The irreplaceable groundwater that sustains the Darling Downs agricultural region must be protected at all costs," OCAA secretary Paul King said.

"We are seeking to ensure that the impacts to precious groundwater posed by stage 3 are finally properly assessed.

"We have always said the Darling Downs is for farming, not coal mining, and we have no intentions of backing down now."

The mine expansion near Toowoomba in southern Queensland was approved in August 2022.

Groundworks and operations were fast-tracked after the department signed off on water access, with the first shipment of New Acland Mine stage 3 coal to leave the site in October.

However, the Oakey Coal Action Alliance continues to oppose the project, claiming it would be detrimental to local farmers and the environment.

Lawyer Revel Pointon from the Environmental Defenders Office said the appeal would argue the state government and the department made an error in law in approving the water licence.

"We argue the groundwater impacts have still not been properly investigated and are so significant that this application to impact groundwater should have been refused," Ms Pointon said.

"One of the reasons the Land Court originally recommended refusal for this mine expansion was the potential impact to groundwater and the implications of this on future generations."

OCAA remains concerned the mine will deplete groundwater from the aquifers.

New Hope chairman Robert Millner said the new legal challenge would create anxiety for the local community and for the workforce who recently returned to work at the New Acland Mine.

"Less than two weeks ago, New Hope and the local communities around Acland and Oakey celebrated Queensland government Resources Minister (Scott) Stewart officially opening New Acland stage 3 and they have been getting on with the job of resuming operations," Mr Millner said.

"OCAA's new legal challenge will see New Acland stage 3 return to the Land Court for a fourth time and New Acland Coal will be forced to spend yet more time and resources in responding to the 'lawfare' tactics.

"We are hopeful that the Queensland government can see a way to intervene to prevent yet more litigation in the Land Court."

The Department of Regional Development, Manufacturing and Water declined to comment on the latest legal challenge.

Local workers, contractors and local businesses will benefit to the tune of $1billion over the life of the stage 3 mine, according to the company.

The mine's permanent, full-time workforce is forecast to reach 400 employees in the next two years, with 600 workers at the peak of construction.

Australian Associated Press