Up to 10 coal seams, of which three; the Lower, Middle and Upper seams are considerably thicker than the others, occur in the Telkwa coal measures interbedded with mudstone and lesser amounts of silt- stone and sandstone of the Lower Cretaceous Skeena Group. The lower seam ranges from absent to 2.3 metres in thickness, the middle seam approximately ranges from 0.3 to 1.4 metres in thickness and the upper seam ranges from 0.3 to 1.4 metres absent to 1.8 metres. The coal in general is predominantly dull black, usually well bedded with fine laminae of brittle bright coal. Bands of mudstone are common in the coal giving rise to a high ash content of 10 to 82 per cent. Pyrite is quite common and the coal seams exhibit small scale folding and locally intense shearing. Fixed carbon ranges from 25 to 61.8 per cent (one sample 3.7 per cent), volatile matter 21.9 to 28.3 per cent (one sample 14.3 per cent) sulphur 0.49 to 5.42 per cent (dry basis) and cabrific content 14,460 to 15,067 BTU per pound (one sample 1,137).

The structure consists of a series of parallel folds trending northwest. Folding is locally very tight and overfolding is present in places. Numerous northwest trending normal and reverse faults which are mainly steep dipping to vertical and shear zones are also present. Displacement on the faults appears to be limited.