Four main coal intervals occur in the Lower Cretaceous Lower Gething Formation of the Bullhead Group. The lowest 30 to 35 metres above the Cadomin Formation (Bullhead Group) averages coal 1.5 metres in thickness with a maximum of 2.2 metres in the southwest and thins towards the northwest and southeast. The second zone, 115 to 120 metres above the Cadomin Formation, or Grizzly seam, may total 10 to 12 metres thick, however individual intervals are normally less than 4 metres. Thickness appears to vary laterally with occasional washouts. The Pump zone lies 30 to 35 metres above the Grizzly seam and varies in thickness from 4 to 6 metres, of which approximately 3 metres is coal. Variations in thickness and lithological characteristics are common in this zone. The topmost coal zone "B", 215 to 220 metres above the Cadomin Formation, contains an upper and lower component. The total coal thickness (1.5 to 2.5 metres) is separated by 10 to 12 metres of mudstone. The Gething Formation in the area is divisible into three parts with a total thickness of 400 to 450 metres.

The Lower Gething Formation is composed of sandstones, siltstones, mudstones, carbonaceous mudstones, the principal coal zones and conglomerates. The overlying Middle Gething Formation contains distinctive brackish/marine very fine-grained sandstone/ siltstone and calcareous mudstone. The Upper Gething Formation is 8 metres thick and comprises calcareous sandstones and thin mudstones, and only occurs in isolated areas as a result of erosion.

The Merrick, Jilg and Triangle prospects were all part of the British Petroleum Exploration's Sukunka North project area on the west side of the Sukunka River south of Burnt River, in 1979 (Coal Assessment Report 671). The Sukunka North block is a synclinorium whose axis trends northwest and which is faulted by several thrust faults. The Jilg project lies on the northeast flank of Mount Jilg, north of Rocky Creek and south of Burnt River.

A major thrust fault separates the area into a northern half incorporating the Gates Formation (Fort St. John Group) and younger strata, while the southern segment is underlain by the Gething Formation and older strata. Fault throw is at least 350 metres. Other west dipping thrust faults occur with throws of 10 to 60 metres.