Cook Mine is in the southern part of the Bowen Basin, and lies on the eastern limb of the Comet Anticline. The strata dips gently, usually <5 degrees to the east, striking slightly east of north.
The upper part of the stratigraphy consists of the Rewan Fm., which is predominantly a grey/green claystone varying in thickness from 80 m to 200 m. The coal bearing Rangal Coal Measures unconformably underlie the Rewan Formation. The upper section of the Rangal Coal Measures consists of four seams interbedded with lithic sandstone, siltstone and carbonaceous claystone strata.
The Rangal Coal Measures contain five main seams (in stratigraphic order from shallowest to deepest): Aries, Castor, Pollux (Argo), Orion and Pisces seams. The main target for underground mining is the Argo seam (4.7 m thick), which is currently being mined.
The depths of the Aries seam (top coal) vary from 110-130 m in the western area to 220-230 m in the eastern area. The thickness of the Aries seam is generally between 1-1.5 m. The Aries Lower Seam (ARL) is not continuous and shows an average thickness of 0.6 m. Where present, it occurs from 1 m to 4 m below the Aries Seam (AR).
The Castor seam is between 10 m and 20 m below the Aries Seam. The Castor average thickness is 2.5-3 m but can locally decrease to 0.5 m or increase to 4 m due to faulting.
Approximately 15 m below the Castor seam is the Argo Rider (AGR). This coaly mudstone band, which gener ........
