A failed Queensland energy company has been found guilty of causing serious environmental harm by polluting the Darling Downs with hazardous contaminants despite warnings from scientists.

Linc Energy has been on trial for weeks at Brisbane district court, where the jury was told that toxic gas leaked from its operations between 2007 and 2013.

The company was charged with five counts of wilfully and unlawfully causing environmental harm.

During the trial, the court heard Linc operated four underground coal gasification (UCG) sites in Chinchilla, where it burnt coal underground at very high temperatures to create gas.

Its operations left water polluted to the point it was unfit for stock to consume.

Scientists and workers warned about gases bubbling from the ground but the company kept operating.

Crown prosecutor Ralph Devlin QC said the Linc CEO, Peter Bond, was aware of guidelines to safely manage UCG operations but had never directed staff to follow mandated practices.

“Bond prioritised Linc’s commercial interests over the requirements of operating its mining activity in an environmentally safe manner,” Devlin said. “Linc did nothing to stop, mitigate or rehabilitate the state of affairs that Linc itself had caused.”

The damage was done, in part, by Linc injecting air into the ground as part of the UCG process.

That created and enlarged fractures.

Linc tried to concrete surface cracks and use wells to control pressure but it did not sufficiently reduce risks or damage, the court was told.

Scientists who visited the site gave evidence during the trial and on Monday Linc was convicted of all five charges.

Sentencing has been listed for 11 May.