IPC lies within the Permo-Triassic Bowen Basin. The Bowen Basin consists of 10 kilometre (km) thick sequences of volcanic, shallow marine and terrestrial sediments and is categorised back-arc to foreland basin.

The general stratigraphy of IPC includes (oldest to youngest)
- Lower-Permian Reids Dome Beds;
- Lower-Upper Permian Back Creek Group;
- Upper Permian Blackwater Group, and Rewan group.

Coal seams occur within the Rangal Coal Measures which are Late Permian in age. These seams dip gently to the east at approximately 5 degrees.

The coal seams found within the Rangal Coal Measuresare the Leichhardt, Leichhardt Upper and Leichhardt Lower, and Vermont.

The seams have a cumulative thickness of approximately 7-10 m across the deposit.

The Vermont seam was not included in the resource estimate due to the lack of geological information. The results at hand indicate the coal to be of poorer quality.

The depth limit of potential open-cut mining varies based on multiple and variable inputs. Presently the limit of open-cut mining is likely to occur between 100 to 150m (depth from surface). If underground mining were to take place, a minimum mining thickness of 1.5m would be required. As such a minimum seam mining thickness was applied to depths >150m, thereby excluding any seams <1.5m thickness from the resource estimate.

Absolute depth of resource was a maximum of 330m from topography.

The mining methodology considered for this estimate is:

• a combination of cast, doze, dragline or truck & excavator to move waste into the adjacent strip or dump. The strip width selected is nominally 55m at IPM and 50m at IPE.
• Drilling and blasting (D&B) of the in situ waste.
• A maximum horizon of 50m of waste is allocated to the dragline.
• Remaining waste is removed by truck and excavator.
• Coal mining using excavators and rear dump trucks haul the coal to the Isaac Plains Complex Coal Preparation Plant (IPC CHPP) for washing.
• Parting > 0.3m thick is stripped separately.

The coal from IPE has been successfully processed through the Isaac Plains CHPP since 2018. Washability simulations from exploration cores show that the remainder of the IPE deposit is similar in character and is therefore very unlikely to have any processing limitations.