SA has approved trials of a controversial mining technology that is banned in other states.

Leigh Creek Energy this week announced it has received final approval from the South Australia’s Energy and Mining Minister for a three-month trial of underground coal gasification (UCG) at the old Leigh Creek mine site.

UCG, otherwise known as ‘in situ gasification’, involves setting fire to underground coal and extracting the gases.

The Queensland Government banned UCG in 2016 and after Linc Energy caused serious environmental harm.

Linc Energy was charged with five counts of wilfully and unlawfully causing environmental harm between 2007 and 2013 at Chinchilla and was fined $4.5 million.

It was described at the time as the worst contamination event in the state's history.

Conservation SA chief Craig Wilkins said the environment body is “outraged”.

“UCG has been banned interstate and right around the world because of the damage it causes,” Mr Wilkins said.

“We simply do not believe the assurances from the company that they have finally worked out how to do it safely.

“The same claims were made by Linc Energy at Chinchilla in Queensland just before they caused such widespread devastation there. Why should we take the risk here?”

Leigh Creek Energy executive chairman Justyn Peters says it is a proven technology.

An independent assessment found “the scenario at Leigh Creek is vastly different to that at Chinchilla, in terms of geology and operations”.

“The State Government's environmental approval for this project came on the back of an expert independent assessment report developed to summarise potential issues and environmental risks associated with the Leigh Creek Energy trial, and how they will be managed,” Mr Peters said.

He said the trial would show that UCG can be a viable gas production technology in the future.

Traditional owners say that with coal having been mined at the site for over 12 years up until 2015, now is a time for it to rest.

“We're very concerned because people live in that area and it's time for healing of the site, not any more destruction,” Adnyamathanha traditional owner Vince Coulthard said.

“It's going to pollute that whole area and poison it — that's our concern.”

Energy and Mining Minister Dan Van Holst Pellekaan the short-term pilot plant would be run in a very controlled and temporary situation.

“After the pilot plant is completed, all consultation with local people with regard to the environment, with regard to cultural issues, with regard to every issue that exists starts again,” he said.