Chromite-platinum mineralization of clinopyroxenite-dunite massif Zheltaya Sopka, North Ural

The paper presents the new data on platinum group minerals (PGM) and chromite from the Zheltaya Sopka massif, North Urals. Few chromite bodies along with specifc composition of chromite indicate weak ore-forming processes developed in this massif. Minakawaite (RhSb) and chengdeite (Ir3Fe) are found for the frst time in the Uralian Platinum Belt. The PGM assemblage of the Zheltaya Sopka massif is compared with that of the Iov, Yuda, and Sosnovsky dunite massifs of the northern part of the Uralian Platinum Belt. As a result, similar PGM assemblages with domi¬nant minerals of late assemblages are established in dunites of the Zheltaya Sopka massif. Chromites of the massif show no evident chromite-magnetite trend typical of clinopyroxenite-dunite massifs of the Urals and are relatively enriched in Cr2O3 and Al2O3 in comparison with chromite of other UPB massifs.

Platinum and platinoids in the Bolotisty gold-placer deposit (Khabarovsky Krai, Russia)

The article shows the results of studies the platinum mineralization (within the framework of studying the complexity of deposits) in the waste of heavy concentrate in the southeastern flank of the Bolotisty gold-placer deposit, which the located in the Khabarovsky Krai (Russia). The deposit is localized in the “erosion window” among the covers of Miocene basalts and Eocene andesites, where Cretaceous sedimentary, tuffaceous-sedimentary rocks of the basement of the volcano structure, broken through by an Eocene intrusive body of intermediate and basic composition, come to the surface. An abbreviated mineralogical analysis for monofraction of precious metals was carried out for a concentrate fraction weighing 1.813 kg with a grain size of -3.0 + 0.1 mm. Gold and platinum were found - 1.38 mg and 1.08 mg. Platinum has an iron impurity up to 3-5 % Fe and Cu, Ir, Rh impurities are variable. There are plate-like inclusions of native osmium with an admixture of ruthenium in 43 % of the studied platinum grains. There are single inclusions of ehrlichmanite. A large amount of high-temperature dipyramidal quartz, along with magnetite, chromite, tourmaline and other minerals is a characteristic feature of the concentrate and platinum grains of this area.

Remote sensing as a method of predicting PGM mineralization based on the results of the study of the Eastern Sector Bushveld complex

In this paper, a study of the differentiated Bushveld complex (South Africa) is carried out on the basis of remote cosmic and gravimagnetic methods. The article shows the possibility of using Landsat 7 ETM+ multi-zone space imagery and brightness characteristics to predict platinum mineralization in new promising areas. Analysis of the values of the gravitational field showed that in the area under study, platinum mineralization is concentrated in a fairly narrow range of values, which makes it possible to use this data as a search feature. The main conclusions have been formulated and the possibilities of the Landsat 7 ETM + multi-zone space survey to forecast platinum mineralization in new promising areas have been clearly demonstrated. The conducted studies prove the efficiency of the integration of remote (space and geophysical) to improve the approach to prospecting for platinum-coppernickel mineralization.

Platinum metals on the Bam gold ore deposit of the Upper Amur region

The problems of complex extraction of noble metals (Ru, Rh, Pd, Ag, Os, Ir, Pt, Au) during the development of gold-silver deposits have recently acquired increasing practical importance and relevance, due to the clear tendency to exhaust the base of available ores, their concentration of useful components and deterioration of mining processing conditions. The aim of the work was an additional study of platinum mineralization in ore objects at the large Bam gold ore deposit of the Upper Amur region and obtaining estimates of noble metal contents by atomic absorption, electrochemistry and chemical analyzes. It is shown that industrial concentrations for mining are gold and silver, and platinum metals are present at concomitant concentrations and do not reach the values required for cost-effective industrial processing. The revealed peculiarities of the Bam deposit are superposition of high-temperature and low-temperature stages of mineralization of precious metals within the ore columns, which leads to averaging of general geochemical regularities and leveling of characteristic local differences. It is noted that platinum mineralization increases with depth and proximity to the source of volcanic heat, just like the relative sample of gold.

Au-Ag-Pd-Pt mineralization in sedimentary rocks associated with Triassic carbonaceous silicites of Sikhote-Alin

Subject.The paper is devoted to the study of the gold-silver-palladium-platinum mineralization of the streaky systems in the sedimentary rocks associated within the Triassic carbonaceous silicites of the Taukhinsky and Samarkinsky terranes of the Sikhote-Alin.Materials and methods.In the process of investigations we studied the metamorphosed carbonaceous siliceous-clay rocks and systems of the mineralized fractures in the Triassic siliceous-clay and siliceous (including jaspers) rocks of Shirokopadninskaya, Vysokogorskaya and Gornaya areas, as well as in the sandstones (unclarified age) of Gornaya area. The samples for the analytical study were taken with the lump way. To estimate the content of precious metals in the rocks, cut by the systems of the mineralized fractures, we used the fire assay and atomic-absorption methods. The analyses of minerals (in polished sections) have been done using the JXA-5A and JXA8100 microanalysers.Results.The gold-silver-palladium-platinum mineralization in the siliceous and clay-siliceous rocks, as well as in the sandstones is restricted to the systems of the mineralized fractures and by many features are analogous to the precious-metal mineralization of the black-shale formations. It is represented by native forms, disordered solid solutions, and intermetallic compounds of different metals. The specificity of the Au-Ag-Pd-Pt mineralization is a wide distribution of copper gold, Ni-, Cu-, and Pbbearing gold, and Zn-bearing platinum. Native elements and intermetallic compounds, including those of precious metals, are not rarely associated with the organic matter testifying to the active participation of carbon and, probably, hydrogen that provided the high- and ultra-reduction character of the processes of mineral formation.Conclusions.The presence of the mineral forms of different maximum reduced metals is caused by the influence of the organic matter of the Triassic carbonaceous silicites. This consisted in the removal of the most volatile components, and first of all the poorly bound water and hydrocarbons from the carbonaceous rocks through the contact metamorphism related with the injection of the granitoid intrusions of Cretaceous plutonic and volcanoplutonic belts.