MINERALOGY OF THE ALLOWER GOLD DEPOSIT OF THE R. ZASLONKA (GORNAYA SHORIIA)

Abstract

Link for citation: Pshenichkin A.Ya., Gavrilov R.Yu. Mineralogy of placer gold deposit of the r. Zaslonka (Gornaya Shoria). Bulletin of the Tomsk Polytechnic University. Geo Аssets Engineering, 2023, vol. 334, no. 5, рр.129-137. In Rus. The relevance of the work is caused by the need to replenish the mineral resource base of gold on the basis of comprehensive information obtained recently using a modern analytical base. Purpose: to study the mineralogical composition of samples of the placer deposit of the river Zaslonka (Gornaya Shoria). Methods: mineralogical studies, crystal morphology, X-ray spectral analysis, scanning electron microscopy. Object: samples of concentrates from the alluvial gold deposit of the Zaslonka river (Gornaya Shoria). Results. The authors carried out the study of the mineralogical composition, including the morphology of gold particles, samples of black concentrates on the MBS-10 binocular microscope and OLYMPUS SZX10 stereomicroscope, and slags after gold melting during the preparation of doré alloy on a Hitachi S-3400N scanning electron microscope. Photomicrographs of various types of gold particles and other minerals were taken. As a result of the research, it was found that the vast majority of gold particles belong to very small (68,71 %), as well as to small (14,69 %) and thin (12,47 %) size classes. Gold concentrates, after enrichment on a flotation table, are weakly radioactive due, apparently, to a thin dissemination of Th-U-containing minerals, which is confirmed by the study of slags on an electron microscope after melting gold during the production of doré alloy, where uranothorite, zircon and gold are found in the form of granular spherules. There are, apparently, three sources of gold entering the placer: 1) gold in the «shirt», covered with dark gray, almost black dense films, which is older gold and probably has a more distant source of drift; 2) gold of medium degree of roundness – flattened and lumpy golden-, dull-yellow and silvery-yellow in color, the sources of formation of which were medium-temperature and medium-distant quartz veins of the area; 3) unrounded golden-yellow gold, formed from nearby quartz weakly gold-bearing veins. The poor mineralogical composition of concentrates (and the almost absence of oxidized sulfide minerals, except for pyrite) indicates the presence of low-sulfide medium-temperature quartz veins with a low content of fine gold in primary ores.