About 7.5Mt run-of-mine coal may be extracted using a bord and pillar technique with any potential underground activity able to run in parallel with open cut operations at either Isaac Plains or Isaac Plains East, the company said.

“This underground opportunity would require minimal capital expenditure as it would utilise access from the existing highwall and surplus capacity within our wash plant and rail loadout infrastructure,” Stanmore said.

The company’s updated JORC compliant open-cut reserve for the Isaac Plains Complex increases the total open cut mining life from three years to 10 years based on a steady state production rate of 1.5Mtpa ROM coal.

The output of reserves modelling indicated a seven year average prime strip ratio (bank cubic metres/ROM tonnes) of 11:1, with the first four years at sub 10:1.

Based on contracted overburden removal and mining costs, the improved strip ratio at Isaac Plains East is estimated to result in an average free on board cost reduction of about $A20 per product tonne in the first four years when compared to the existing planned three years of Isaac Plains open cut.

”The company has made strong progress with field activities and ongoing baseline studies which will underpin the submission for the proposed Isaac Plains East Mining Lease,” Stanmore said.

“A top tier environmental consultant and dedicated internal environmental resources continue to manage the submission, which is anticipated to be lodged in the December quarter of 2016. The company is targeting grant of the mining lease within the second half of 2017 with mining to commence shortly thereafter.”