In EPC927 the target seams are a part of the Late Permian Rangal Coal Measures. The top of the Rangal Coal Measures is typically marked by the transition from carbonaceous sediments to the younger fluvial sequence of green coloured, non-carbonaceous siltstones and lithic sandstones of Mesozoic age, part of the Rewan Group. The Rangals dip to the west off the flank of the Comet Ridge towards the Denison Trough.

Underlying the Rangal Coal Measures is the Upper Permian Burngrove Formation which comprises light blue-green coloured sandstones, greenish grey siltstones and mudstones, and banded coal seams which are frequently interbedded with light brown coloured tuffs and tuffaceous mudstones.

In EPC927 Tertiary aged sediments unconformably overlie Permian and Triassic strata and generally consist of multicoloured claystones and quartzose sandstones with bands of ironstone and silcrete.