| Summary: | From available records and data of colliery product samples, an area within the Witbank and Highveld coalfields was selected for this study. The petrographic and elemental nature of the coal seams have been derived from the relationship between the volatile natter content and the calorific value, both expressed on a dry ash-free basis (Snyman et al, 1983; Barnard, 1987). These derived values were complemented by ash_ analyses of colliery product samples, paleotopographic data and seam thickness. These data provided information on the paleoenvironmental conditions during peat accumulation and deposition. Computerized subsurface mapping techniques were applied to record various chemical and petrographic parameters. The existence of major channel complexes culminating in outwash streams towards the south is postulated. During the formation of the basal seams these trunk channels were up to 6 km wide and trended generally from east to west and from north to south along loT.v gradients. The channels follow topographical lows and skirt topographical highs. The vegetationstabilized channels aggraded upwards at a rate consistent with peat accumulation. The channels were fed by melt-water which originated from the northwards receding glacial ice-cap. Low energy currents led to the wide lateral distribution of autochthonous coal seams. The channels led to the transportation and redeposition of inertodetrinitric material of hypautochthonous origin. The coal seams associated with channel areas are generally thinner and the resultant coals are usually inertinite-rich. These coals have a brittle character and tend to become more shaley towards the south. A close relationship was established between the mineral matter characteristics and coal type of the No. 2 Seam. The inertinite-rich coals within the major channel areas contain mineral matter which is richer in acidic minerals. These minerals are quartz, normative rutile and kaolinite. Coals which formed in interchannel areas and swamps have generally higher vitrinite ...
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