The additional reserves came from the key Escarpment deposit of the project, plus a maiden reserve of 4.4Mt for the neighbouring Whareatea West deposit which Bathurst acquired off Galilee Energy in late 2010.

Bathurst said its reserves came from less than 20% of the total Buller project area, while the Whareatea West reserves cover only 40% of the surface area of that block.

The project’s total proved coal reserves are 13.8Mt while 3.5Mt is probable.

Out of the resources, 28.6Mt is measured and all within the South Buller area of the project.

The explorer’s plans to mine the Escarpment deposit have faced a legal challenge from green groups, but the Environment Court aims to settle the dispute through mediation.

Mining at the Escarpment deposit was previously targeting production this quarter at a rate of up to 0.7Mt per annum.

Bathurst aims to ramp up to 2Mtpa from the South Buller areas during the 2012-13 financial year and hit 4Mtpa in the 2014-15 financial year through mining in the North Buller areas of the project.