The Queensland Government late last year transferred nearly $5 million from an environmental assurance fund to the controversial new owners of the Blair Athol coal mine, five months after they bought the mine for a token $1.

The Department of Environment and Science has confirmed to 7.30 it transferred "surplus" funds to the small resource company, TerraCom.

The transfer has angered both environmental groups and the LNP opposition, prompting accusations the company is gaming the system.

Blair Athol was formerly owned by a consortium led by resource giant Rio Tinto, which shut down the operation in 2012 but did not carry out the required land rehabilitation.

The State Government allowed Rio Tinto to offload the mine to TerraCom last May, on the condition Rio paid an environmental financial assurance of nearly $80 million.

The deal was criticised by green groups as insufficient and Environmental Defenders Office Queensland has launched a legal challenge.

Now 7.30 has learnt TerraCom began the process to get access to part of that $80 million just 16 days after taking ownership of the mine.

The Blair Athol coal mine in operation in 2012. ( Supplied: Rio Tinto )

An Environment Department spokesman said TerraCom first submitted an amended plan of operation for the mine on June 1, paving the way for an agreed reduction in the required financial assurance several months later.

"The Queensland Government currently holds $74,941,532 in financial assurance for the Blair Athol coal mine," the spokesman said.

"The surplus financial assurance held by the state was returned to Orion [a wholly owned subsidiary of TerraCom] on October 27."

There is no dispute over the legality of the transfer — as the holder of the environmental authority, TerraCom was deemed to be owner of the $80 million financial assurance even though it was paid by the Rio Tinto consortium.

Queensland Opposition Leader Deb Frecklington said the State Government had made no public announcement about transferring part of a controversial environmental security to a small company that has former Labor politicians Jim Soorley and Craig Wallace on its board.

"There is a culture of secrecy that is rife within this Labor Government," she said.

"Labor only talk about openness and integrity but instead they continually treat Queenslanders like fools."

Lock the Gate spokesman Rick Humphries, a former Rio Tinto adviser on land rehabilitation, said the environment department was allowing TerraCom to game the system at taxpayers' expense.

"They're effectively propping up what is a financially distressed, heavily indebted company," he said.

The Blair Athol coal mine began operating again last August. ( ABC News )

Mr Soorley described this as "typical nonsense from the Greens".

"We had to do a comprehensive change to our plan of operation, and we'd agreed to rehabilitate 50 hectares, which has been done," he said.

"The state was holding $4.7 million that they were no longer entitled to, so they had a responsibility to return that money," he said.

Queensland Resources Council chief executive Ian Macfarlane backed TerraCom.

"It's our understanding the department calculated the appropriate amount of financial assurance, as per the process required under the Queensland regulatory framework for mining," Mr Macfarlane said.

TerraCom recorded a profit after tax of $5.037 million for the last financial year, with the independent auditor finding "significant uncertainty as to whether the consolidate entity will continue as a going concern".

The Blair Athol coal mine recommenced operations last August.

A leaked State Government report in 2016 found a $3.2 billion shortfall in financial assurances for Queensland coal mines.

A 2014 auditor-general's report found the financial assurance held by the state has "historically been insufficient", but that in recent years the Environment Department had made "a concerted effort to increase the amount held and to reduce the gap".