In a rationalisation of its extensive exploration acreage formerly held in the upper South-east of South Australia for the purpose of coal exploration, Western Mining Corp. (WMC) has partially relinquished most of the ground that it previously...
In a rationalisation of its extensive exploration acreage formerly held in the upper South-east of South Australia for the purpose of coal exploration, Western Mining Corp. (WMC) has partially relinquished most of the ground that it previously held except for the portion which contains the Kingston coal deposit. Within the now relinquished licence portions, which together cover a total area of ~8600 square km, exploratory test drilling of 129 [not 123] rotary mud vertical open holes totalling 16,231 m, including 2 m of core drilling, evaluated the coal and oil shale potential of the lower Tertiary Dilwyn Formation and the coal potential of the basal Cretaceous unit of the Otway Group. Records are presented of encountering 8 Cretaceous coal seams up to 1.0 m thick that were intersected over hole depths ranging from 170 - 330 m, while 26 shallower Tertiary coal seams up to 6.4 m thick were intersected at between 47 and 156 m depths. 70% of the Tertiary seams are 1 m or less in thickness. For these shallower seams, the minimum overburden to coal thickness ratio is 17. Their oil shale yield of liquid paraffinic hydrocarbons as obtained by retorting ranges from 1 to 9 litres/tonne (7 samples, dry basis). 56 selected downhole samples of carbonaceous sediments were collected from 19 of the drillholes and examined palynologically to determine the sediments' biostratigraphic ages and to infer their environments of deposition. Probable Permian sediments were encountered in 11 holes, six of the holes being located near Kingston SE. In another hole, SE11, that was collared 23 km south-east of Naracoorte, muddy siltstones and sandstones lying below 106 m depth were dated from palynological determinations. It has been concluded by WMC that the coal seams found are not economic, due to them being too deep and thin. In other work, 23 bottomhole bedrock drill cuttings samples were selected for assaying from the various types of basement rocks as penetrated in 55 of the WMC exploratory holes, that were mainly identified as Kanmantoo Group equivalents or Ordovician granites and granite rhyolites. No anomalous base metal values were detected. A portion of the subject surrendered multi-licence area has subsequently been been retained by WMC under a newly issued licence (EL 1093 Blackford) that was granted on 20/12/1982.
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