A Brisbane-based mining company has agreed to spend more than $2 million to rehabilitate land in southern Queensland after an investigation into alleged illegal mining.

New Hope Group had been under investigation since 2020 over "alleged unauthorised disturbances" in an area known as West Pit at its New Acland mine near Oakey.

A Qld Department of Environment and Science (DES) spokesperson said the company had applied for the rehabilitation agreement as an alternative to enforcement action.

"The agreement means the habitat will be suitable for koalas and other fauna at its New Acland Coal Mine, 35 kilometres north-west of Toowoomba," the spokesperson said.

Court the alternative

The mine's general manager Dave O'Dwyer said the agreement was an alternative to taking the matter to the courts.

He said its West Pit mining operation had been included in its plans.

"However, the DES disputed this as an accepted form of authorisation," Mr O'Dwyer said.

The agreement also includes plans to set up a wildlife corridor connecting existing known koala populations in the area.

"More than 100 hectares of land will be planted with eucalyptus, paper bark and other refuge trees, designed to significantly boost the local koala population," Mr O'Dwyer said.

Enquiries to end

DES said the deal put an end to extensive enquiries into the matter and would result in about 140 hectares of land for conservation and koala habitat once mining ended at New Acland.

It said it would now finalise the matter and monitor compliance at New Acland Coal Mine.

The company has also committed to reviewing staff skills, training, and its permit to disturb system.

It is currently awaiting approvals from the Queensland government to begin its stage three expansion of the mine.