COMPARISON OF THE MINERALOGY AND GEOCHEMISTRY OF THE KEROSENE CREEK MEMBER, RUNDLE AND STUART OIL-SHALE DEPOSITS, QUEENSLAND, AUSTRALIA

The contiguous Rundle and Stuart oil shale deposits of Queensland, Australia, contain resources equivalent to more than 5·109 bbl of shale oil. Characterisation of these Tertiary oil shales is important in selecting suitable processing technology. Detailed stratigraphic analysis at two locations revealed significant variations in ore type over the most prospective Kerosene Creek Member in both the Rundle and Stuart deposits. The stratigraphy, geochemistry and mineralogy are comparable with differences mainly attributed to location relative to the edge of the lake during deposition. Ore-type samples were analysed for major and trace elements relevant to processing. Mineralogical compositions were determined by chemical analyses, X-ray diffractometry and electron microprobe analysis. The major ore types were not clearly discriminated by chemical composition or mineralogy. Minerals which most effect processing of the oil shales included smectite, kaolinite, calcite, pyrite and siderite-type minerals. Carbonate mineralogy proved particularly variable and dependent upon depositional environment. Calcite, magnesian calcite, dolomite and a wide range of manganoan and magnesian siderites are observed. Siderite appears to be formed under very shallow lacustrine conditions. © 1990.