The company volunteered this information to the Federal government despite it receiving approval beforehand because of changes to the EPBC Act in regard to water tables.

“Not taking the proposed action would result in the closure of the Kestrel mine, the loss of significant capital invested in the mine, employment and royalties,” Rio said in its submission.

“There are no alternatives to taking the proposed action. This is because the proposed action contains an economic resource located in a fixed location. Accessing this resource from an existing mine avoids the need to construct new surface infrastructure (for example coal handling and preparation plant, buildings, stockpiles) and avoids new surface disturbance for this infrastructure.”

Rio is seeking a mining lease for the Kestrel extension, which is expected it to produce about 5.7 million tonnes a year over the next 20 years.

A spokesman for Rio told International Coal News: “We are confident approval will be granted for this procedural step to allow the next phase of mining at Kestrel, which has been operating since 1999.

“Our planned mining activities in this area have been extensively studied and are well understood, having already been considered by the Commonwealth government under the EPBC Act on two previous occasions.

“We have voluntarily referred this application again due to more recent changes in the EPBC Act.”

The Kestrel longwall mine produced 2.16Mt of hard coking coal in the 2014 calendar year.

Rio’s third quarter hard coking coal production was 12% lower than the second quarter due to a scheduled longwall changeover at the high-performing Kestrel mine.

Production from Kestrel declined from 752,000t in the June quarter to 429,000t in the September quarter.