Rio Tinto Energy chief executive Harry Kenyon-Slaney said even if a successful outcome could be delivered through the legal system, it would take months and come too late to avoid impacts on production and jobs at Mount Thorley Warkworth mine.

“We are committed to doing everything we can to avoid the loss of production and associated jobs for our workforce of 1300 people at Mount Thorley Warkworth mine, and that is why we are proceeding with this appeal,” Kenyon-Slaney said.

“However, we’ve already spent close to four years trying to secure approval for this mine extension and it is unlikely the legal system can deliver an outcome in time to avoid impacts on Mount Thorley Warkworth.”

The case is being supported by a cross appeal lodged by the NSW planning minister Brad Hazzard.

If the appeal is successful, the most likely outcome would be returning to the Land and Environment Court to have the relevant point re-heard, potentially by the same judge.

The appeal is being heard on a relatively narrow scope, confined to points of law. This excludes any further consideration being given to the merit of the judgement made by Land and Environment Court Chief Justice Brian Preston.

“The legal blow we were dealt in April is now forcing us to operate in a reduced footprint which impacts productivity and drives up costs. If this continues, it will be impossible to maintain production levels at the mine which in turn means fewer jobs,” Kenyon-Slaney said.

“We are continuing to review the situation at Mount Thorley Warkworth mine with an aim to protect production and jobs as much as we can.

“The workers at this mine are doing everything within their power to combat the challenging environment confronting the Australian coal industry.

“They are delivering outstanding production in a bid to keep the operation profitable and it would be very sad to see their jobs taken away by the Land and Environment Court’s decision.”

Kenyon-Slaney said the Chief Justice Preston’s judgement had a number of errors, such as finding the offsets package for Warkworth Sands Woodlands was unacceptable because “there is no current example of a recognised area of Warkworth Sands Woodlands Endangered Ecological Community, which has been created by rehabilitation from derived grassland”

Images presented during the trial showed areas accepted by the Environmental Defenders Office’s expert Stephen Bell as high and medium-quality Warkworth Sands Woodlands had grown back after mining with no more rehabilitation than fencing and removal of cattle, Kenyon-Slaney said.

He also refuted the finding in the judgement that “20 properties are so badly noise-affected that the owners are given an entitlement to have their properties acquired at the outset of the project”

The owner of only one residence would obtain the right to require acquisition due to the Warkworth Extension alone. The other 19 owners referenced by the Chief Justice already hold voluntary acquisition rights due to impacts from several mines, he said.

“This is the first time an approval to continue the path of an existing, open-cut mine has been overturned by a New South Wales court and it has raised to unacceptable levels the approvals risk facing mining companies looking to invest in this state,” Kenyon-Slaney said.

“How can companies have the confidence to proceed with multi-billion dollar investments that take decades to deliver returns if the decisions of the Planning Minister, the independent Planning Assessment Commission and the government departments charged with assessing whether projects should be approved can simply be over-ruled at the end of the process?

“The Land and Environment Court decided to overrule the decisions made by these authorities not because of any errors in law or procedure made by them, but because it disagreed with the outcome of a rigorous planning process that determined the mine extension was in the overall public interest.”