Orenburg State University, Orenburg, Russia

G. A. Ponomareva, Associate Professor, Candidate of Geological and Mineralogical Sciences, galy.ponomareva@mail.ru

Black shales are widespread in the world and are promising for the investigation as they are associated with the largest deposits of gold, and sometimes with the increased contents of platinum, palladium and other rare metals. Black shales are related to carbonaceous type. They represent sedimentary rocks. The article describes the studies on determination of platinum and palladium contents of ore at the Kirovskoe and Vasino gold sulphide deposits. The ores of these deposits are associated with Paleozoic black shales of the eastern part of the Orenburg Region in the Ural. The enclosing rock mass of the Kirovskoe gold sulphide ore deposit is the carbonbearing terrigene–carbonate strata of the lower Carboniferous age, as well as the embedded residuum and Jurassic sediments (bleaching clay, clayey gruss-and-rubble debris, coaly and coaly–limy mudstone, mixtite, slide breccia). At the Vasino deposit, the narrow and steeply dipping gold-bearing zones are composed of metasomatic rocks of light porphyritic quartz–carbonate–feldspar composition, as a rule. The zones of residuum are associated with oxidized and semi-oxidized ores. In the test samples of gold sulfide ore, the contents of platinum, palladium, gold and silver were determined by the atomic absorption spectroscopy and using the proprietary patent method. The increased contents of platinum and palladium are found in the test gold sulphide ore. The above-average concentrations of platinum (539 mg/t) and palladium (196 mg/t) are revealed at the Vasino deposit in the Kumak ore province. The values of concentrations of platinum and palladium, as well as their ratios in ore of both deposits point at the ultramafic nature of their distribution. The concentration of platinum, with allowance for the average values, exceeds the concentration of palladium more than by 2 times. The Kirovskoe and Vasino deposits feature the platinum–palladium specialization which is typical of the deposits in different formations in the eastern part of the Orenburg Region.

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