To assess the possibility of selective disintegration and reduction of overgrinding of hard-to-reproduce ores, optical microscopic and X-ray microtomographic studies were carried out and quantitative characteristics of morphological parameters of disseminated and rich cuprous ore samples from Norilsk-type Oktyabrsky deposit were identified. Among quantitative morphological parameters the most informative are area, perimeter, edge roughness, sphericity, elongation and average grain spacing for disseminated copper-nickel ores; area, perimeter, edge roughness and elongation for rich cuprous ores. The studied parameters are characterized by increased values and dispersion in ore zones, which is especially important for fine-grained ores, which are difficult to diagnose by optical methods. Three-dimensional modelling of the internal structure of sulphide mineralisation samples was carried out using computed X-ray microtomography, which allows observation of quantitative parameters of grains, aggregates and their distribution in the total rock volume and interrelationship with each other. The evaluation of rock pore space by computer microtomography made it possible to compare the results obtained with the strength characteristics of rocks and ores, including those on different types of crushers. The obtained quantitative characteristics of structural-textural parameters and analysis of grain size distribution of ore minerals allow us to evaluate the possibility of applying selective crushing at various stages of ore preparation
The article presents structural and geotectonic features of Iturup Island, the largest island in the Greater Kuril Ridge, a unique natural site, which can be considered as a geological reference. The structural and geotectonic analysis carried out on the basis of a comprehensive study of the new Earth remote sensing data, maps of anomalous geophysical geophysical fields, and other geological and geophysical materials using modern modelling methods made it possible for the first time to identify or clarify the location of previously discovered discontinuous faults, typify them and determine the kinematics, as well as to establish a more reliable spatial relationship of the identified structures with magmatism with the stages of the geological development of the region. The constructed diagram of the density distribution of the zones with increased tectonic fracturing shows a significant correlation between the distribution of minerals and weakened areas of the Earth's crust and can be used as an alternative method for predicting minerals in the study region, especially in remote and hard-to-reach areas. The presented approach can be extended to the other islands of the Greater Kuril Ridge, thereby bringing research geologists closer to obtaining the answers to questions about the features of the geotectonic structure and evolution of the island arc. The use of customized software products significantly speeds up the process of interpreting a large array of geological and geophysical data.
In the southern part of the Khur area, there is faults system with predominantly North-West strike. This network of tectonic disturbances is one of the most important fault systems in Central Iran which crosses Paleozoic metamorphic rocks, Cretaceous limestones, and Eocene volcanic rocks. Interpretation of satellite imagery ETM+ (Enhanced Thematic Mapper plus, Landsat) and field observations showed the presence of left-lateral shifts along with fault system. This formed the structure of the branch faults at the northeast end of the main fault. Another feature associated with shear dislocations is the rotation of blocks in the northeastern and southwestern segments of the area under study. There are several basins and positive structures within the area such as a series of uplifts and thrusts, indicating the presence of compressional and extensional tectonics. Another part of the work is devoted to the study of the correlation between active faults and earthquakes. Processing of satellite images, field observations, records of micro-earthquakes within a radius of 17 km made it possible to analyze the earthquakes parameters and the position of tectonic disturbances, and, as a result, confirm the presence of active faults in the region. In addition, we have identified three successive stages of the Khur area tectonics: rifting, contraction, change of convergence and uplift direction.
University museums are a group of educational museums of various specializations that are created to support the educational process, serve as a scientific research base for the academic teaching staff and students, and contribute to the knowledge development, transfer, and popularization. The foundation of the scientific and educational tourism cluster on the basis of the two world oldest mining museums and universities will make it possible to create a modern multifunctional structure with a high degree of interdisciplinarity. New forms of cluster interaction will include elements of various industries and fields of knowledge and guarantee not only economic benefits, but also fulfil an important role in the social relations development. The present stage of cluster development is focused on the creation of multifunctional structures characterized by the high interdisciplinary specialization. Special attention should be paid to a combination of the above-listed spheres, for example, the creation of a scientific and educational tourism cluster based on university museums.
Data are presented on the results of X-Ray structural and thermal analyses, data from chemical and microscopic studies of serpentines of chrysotile Mg3Si2O5(OH)4 – pecoraite Ni3Si2O5(OH)4 series from the silicate nickel deposits in the Urals. Nomenclature is updated of the studied serpentines following the regulations of the International Mineralogic Association. It is demonstrated that the studied minerals are the chief ore minerals in serpentinite zones of nickel fields. Issues are reviewed of formation of serpentines of the chrysotile-pecoraite series in conjunction with hydrothermal processes. It is suggested the two-tier structure of the Ural supergene nickel fields, where supergene upper tier has "roots" in the form of hydrothermal lower tier, which significantly expands the area of the search for new fields and opens great opportunities in this ancient district of ore.
The article encompasses new data on geochemistry of dunites forming the Svetloborsky and Nizhnetagilsky ultramafic massifs of the Ural Platinum Belt. Petrogenesis of both massifs is discussed based on their interpretation. The research establishes that both massifs are petro-chemical equivalents of alpinotype complexes and zonal massifs, but at the same time they have their own particularities. Thus, dunites of the Svetloborsky massif are enriched in almost all rare elements compared to the Nizhnetagilsky massif that may be caused by their redistribution during subsequent processes due to intrusion of mafic dykes.
Possibility of the natural electric field formation in conditions of the lateritic weathering crust of the ultra basic rocks in presence of extended in depth magnetite bearing bodies is proved. Theoretical curves of concentration of the dissolved oxygen and oxidized forms of magnetite are obtained. It is enough satisfied coincidence with the experimental data.
Contents of platinum group elements (PGE), gold and silver in oxide-silicate nickel ores of the Buruktal, Ufalei and Elov supergene nickel deposits are determined in relation to their ophiolitic dunite-harzburgite bedrock.
Platinum mineralization in Svetly Bor massif is represented by two promising mineral assemblages: chromite-platinum and platinum-type dunite. Body platinum of chromites lie within the fields of small-and medium-grained dunite central part of the array. Spinel epigenetic vein platinum chromites of Svetly Bor clinopyroxenite-dunite massif have some geochemical features such as high iron content, low chromium and titanium. Changing the chemical composition of the constituent minerals chromites is the result of processes of serpentinization of dunites host and is accompanied by the emergence of new mineral phases. Noble metal mineralization is represented by fine of up to 50 microns, mostly idiomorphic grains isoferroplatinum, tetraferroplatinum, osmiridium.
Chromitites of Nizhni Tagil massif veins in length from a few centimeters to several meters. The contents of rare earth elements in the platinum-veined chromitites characterized by reduced compared with the enclosing dunite values. In quantitative terms, is dominated by light rare earth elements. The positive correlation between the rare-earth elements and platinum group metals in the samples with normal contents. High and extremely high content of PGE in the chromite-platinum ores Nizhni Tagil massif are not accompanied by a significant increase in the concentrations of REE.
Isotope ratio 87Sr/86Sr was determined for the first time for the Ufalei and Sakhara supergene nickel deposits. The average obtained 87Sr/86Sr ratio in the Sakhara deposit (0,70838) is higher then in the Ufalei deposit (0,70697). In both deposits 87Sr/86Sr ratio increases from low-altered serpentinite rocks of the lower part of the deposits (0,70583 and 0,70687) to exogenous iron-oxide rocks of the upper part of the deposits (0,70917 and 0,71004).
Weathering processes and infiltration metasomatic processes in the weathering crusts hyperbasite arrays have a positive effect on the accumulation of rare earth elements. The content of rare earth elements is steadily increasing bottom-up on the profile of weathering. Metasomatic upper profile characterized by a high content of rare earth elements, which leads to the appearance of rare earth elements phosphate mineral phase – xenotime found in this laterite for the first time. The composition of the rare earth elements in incorporating their metasomatic and minerals demonstrates chondritic distribution.
We have analysed chemical of nepouites. NiO content in then ranges from 13,00 to 35,18 %, MgO from 18,29 to 44,61 %, i.e. the composition of nepouite corresponds to the composition of Mg-nepouite. General row of chemical element mobility in lizardite – nepouite ores of the Elov supergene nickel deposit is the following: (Mo, Sb, Se, W)20-35 > (Sn, As, Ni)10-20 > (Pb, Be, U)3-7 > (Ti, Ga, Mn)1-3 > (Th, Rb, Si)~1 > (Al, V, Co, Tm, Zn, Mg)0,6-0,9 > (Yb, Ca, Cu)0,4-0,5 > (Sc, Cr, Zr, Sr, Ba, Y, Ta, TR)0,1-0,4 > (Cs, Nb; Ag, Te, Bi, Au)< 0,01-0,1.
The main geochemical barrier in supergene Buruktal nickel deposit is oxygen oxidized barrier in upper ferrous-oxide zone of the deposit. It makes sharp decrease of chemical element migration. Nevertheless, ore mineral concentrations present oft in complex geochemical barriers: absorbed-oxidized, carbonate-reducing and others. Every type of the geochemical barriers is able to concentrate specific association of migrated elements. That reflected on the different values of coefficients of enrichment in different types of Buruktal metasomatites. Oxidized barrier is more effective for elements with different valence (Fe, Mn), and absorbed clay, ferrous-oxide und manganese-oxide barriers are more effective for the main part of microelements.
The article deals with the distribution of groups of trace elements in four selected types of metasomatic rocks and ores in the Elov deposit: chamosite metasomatic rocks and ores, which are three mineral species: a – chamosite, в – clinochlore –brendleyit-chamosite, с – clinochlore-talc-chamosite, goethite metasomatic rocks and ores, nepouite-chrysotile-lizardite metasomatic rocks and ores, and lizardite-chrysotile serpentinites. Also calculated the coefficients of accumulation of trace elements and formulated conclusions about elements are accumulation or elements are weathered of the above types of metasomatic rocks and ores of the Elov deposit.
The article deals with genesis of chamosite zone in Elov supergene nickel deposit after the example of clinochlore-brindleyite-chamosite nickel ore. According to obtained data, isotope ratio 34 S/ 32 S in millerite from these ore type varies from –35,5 to –45,6±0,6 ‰. This value corresponds to sedimentary rocks und testifies surface exogenous genesis of chamosite nickel ores.
Tectonic fractures of meridian spread, masked by block system of neotectonic breaks, play the leading role in structural control of nickel mineralization in supergene nickel deposits in the Urals. The deposits have long-term genesis and polygenic character. They are characterized by intensive tectonic and hydrothermal workup of Paleozoic substrate and block structure with small amplitude of vertical displacement. All of them have a two-floor structure, where upper supergene floor has a «background» of lower hydrothermal floor. This fact considerably increases the field of geological prospecting and searching of new oxide-silicate nickel deposits in the Uralian region.
In the Buruktal supergene nickel deposit, iron oxides possess vertical mineralogical zoning (bottom-up): magnetite-maghemite-goethite-hematite. The main rock- and ore-forming mineral in the iron-oxide zone of the deposit is magnetite, presented by three generations: primary relic magnetite, surviving from ultramafic rocks; secondary magnetite, forming at serpentinization process and neogenic supergene magnetite. Supergene magnetite, like a goethite, is nickel ore mineral, containing about 1 % NiO. Under the complex thermal analysis data, maghemite-magnetite and goethite have two main diagnostic maximums: exothermal effect of magnetite, caused by magnetite oxidation to maghemite in the interval 317‑340 °С, displays maximum at 327 °С («magnetite» point), and endothermic effect of goethite, connected with loss of constitutional water of the mineral and its transition to hematite in the interval 269‑296 °С, displays maximum at 288 °С («goethite» point).
