Composition Of Ores Research Articles

Study on Impact Crushing Characteristics of Minerals Based on Drop Weight Tests

The degree of difficulty in crushing an ore depends on the composition of the ore itself. Due to different types and compositions of ores, the crushing mechanism of ores during the crushing process is also different. In order to quantitatively analyze the impact crushing characteristics of mineral components in ores, this paper takes pure mineral quartz, pyrrhotite, and pyrite as the research objects and uses the universal drop weight impact crushing test equipment and standard test methods developed by the JK Mineral Research Center of the University of Queensland, Australia, to conduct JK drop weight tests on these three pure mineral samples. The results show that the particle size distribution of impact crushing products is wide, covering all particle sizes from “0” to close to the feed particle size, and the yield distribution of each product particle size is relatively uniform. There are critical values and “energy barrier” effects for the impact-specific crushing energy. The impact-specific crushing energy has a significant impact on the particle size composition and crushing effect of the crushing product, and there is an interactive effect between the impact-specific crushing energy and the feed particle size and mineral type. The impact crushing resistance of the sample can be characterized by using Mohs hardness, impact crushing characteristic parameters, impact crushing resistance level, and the yield limit value t10 of the characteristic crushing particle size. The overall characterization results have good consistency.

Study of spontaneous combustion of the main industrial types of sulphide ores of sulphide- polymetallic deposits of Azerbaijan


 
 
 The article is devoted to the study of the causes and conditions of spontaneous com- bustion of sulphide ores, which may result in endogenous fires that complicate mining operations in mines, causing enormous material damage to the national economy, and often also leading to human casualties. There are several sulphide-polymetallic deposits in Azerbaijan, the reserves of which were approved back in the days of the USSR. Of these, the Filizchay deposit is the most unique in terms of its reserves and ore composition. The development of other deposits adjacent to the Filizchay deposit, separately, is inexpedient because of their small reserves. However, the development of sulphide-polymetallic deposits in Azerbaijan is complicated by the revealed tendency of industrial types of ores to oxidation and spontaneous combustion. In this regard, there was a need for a special study of the chemical activity of sulphide ores and the phenomena accompanying oxidative processes, taking into account the natural features of the deposits in order to obtain the initial parameters necessary for scientifically based technological solutions for their development. Sulphide ores of sulphide -polymetallic deposits of Azerbaijan significantly differ in material composition, conditions of occurrence and mining technical features of their development from the listed deposits, the issues of spontaneous combustion of which have been studied for a long time. Until now, there are no general criteria for assessing the fire hazard of sulphide ores, suitable for any deposit, since the conditions for the occurrence of underground fires at different deposits are different. It is this circumstance that makes it necessary to conduct special studies for each deposit separately. Therefore, the need for a special study of this problem on the example of the conditions of sulphide-polymetallic deposits in Azerbaijan, which are prone to oxidation and spontaneous combustion, is of great importance. Identification of causes and factors affecting spontaneous combustion of sulphide ores, classification of sulphide-polymetallic deposits of Azerbaijan according to the degree of their tendency to spontaneous combustion by analyzing the collected materials, as well as by the results of studies to determine the oxidative activity of sulphide ores. The article presents the results of experimental studies to determine the oxidative activity and spontaneous combustion of sulphide ores of the Katsdag, Filizchay and Katekh deposits, carried out in laboratory conditions by the method of Institute of Mining named after. A.A. Skochinsky, the basis of which is the determination of the oxygen absorption rate constant. It is known that the susceptibility of ore to spontaneous combustion is determined by its oxidizability at low temperatures and depends on a large number of factors. In this regard, the dependence of the total amount of oxygen absorbed by sulphide ores on time has been studied, it has been established that the rate of oxygen absorption by sulphide ores is long-live and slowly fading, but incessant. On the basis of extensive experimental material, a classification of sulphide ores of Azerbaijan according to the degree of tendency to spontaneous combustion according to low-tempera-ture oxidation is proposed, since it is this that forms the basis of the spontaneous combustion process. The classification is also based on differences in textural and structural features and mineralogical composition of ores. Of great interest is also the influence of the size of the free reacting surface of the ore on the oxidation process. Analysis of ore samples shows that for their spontaneous combustion, the most dangerous are its coarse fractions than the dust. The results of the conducted studies allow a scientifically sound approach to planning the sequence of development and designing mines.
 
 

On the gold content in the antimony and mercury mineralization in Priamurye

The data on the geological and structural position, composition of metasomatites, ores, and gold content of antimony and mercury deposits and occurrences of the Priamursky gold-bearing area are presented. It was established that the ores of many of them contain native gold, whose concentration reaches commercial values. Some of the gold-bearing antimony and mercury deposits serve as sources of the formation of gold placers. By the composition of ores, near-ore metasomatites and samples of native gold, the analogues of these deposits and occurrences are the famous gold deposits of Yakutia - Sarylakh of the gold-antimony formation and Kyuchus of the gold-mercury formation. It is recommended to audit a number of mercury and antimony deposits and occurrences in the Priamursky province for gold. As a result, it is expected to identify deposits of gold-antimony and gold-and-mercury formation. In addition, occurrences of antimony and mercury may be indicative of the presence of gold-sulfide formation deposits in the bedrock, similar to a large deposit Mayskoye (Chukotka).

Ore composition and native gold characteristics of an ore occurrence in Eastern Transbaikalia

The article deals with the characteristics of the ores of an ore occurrence of the Munginsky cluster located on the western flank of one of the commercial fields of Eastern Transbaikalia. The ores of this promising ore occurrence are underexplored, especially in the technological aspect, which served the basis for studying their composition and characterizing native gold as their main commercial component. The composition of ores and altered rocks was studied by the following methods: atomic emission spectral quantitative analysis, X-ray fluorescence, as well as phase atomic absorption and atomic emission analysis with inductively coupled plasma ICP-AES. The mass fraction of total and organic carbon was determined in the Central Fire Assay Laboratory of JSC Pokrovsky Rudnik, Blagoveshchensk. The proportion of carbonate carbon dioxide was determined by the method of titrimetric determination of carbon dioxide. The content of gold was given according to the data of assay melting, the content of silver – according to the data of atomic absorption analysis. Petrographic and mineragraphic studies were carried out using an optical microscope Olympus BX-51. The mineral composition of the ore sample was also estimated based on the results of X-ray diffraction analysis. The quantitative mineral composition was studied on the crushed material of the original ore with a particle size of -2 mm using the microscopic study data of transparent and polished thin sections on a microscope Nikon Eclipse LV 100 POL. The content of iron hydroxides was determined from the weight difference after the sample was treated with a 10 % oxalic acid solution in a water bath. Comparison of the results obtained on the ore occurrence with the materials on the ore composition of the closest deposit located in 30 km demonstrates that on the one hand they are similar and uniform, and on the other hand they feature some differences. Their common parameters include a rather high degree of sulfide content of ores and similar chemical and mineral composition with the predominance of arsenopyrite, an increased role of bismuth as well as the predominance of fine gold and its similar morphological characteristics. This fact allows to consider the ore occurrence under investigation as an integral part of a single ore system of the closest deposit.

Substantiation of New Reagent Compositions for the Effective Extraction of Rhenium in the Processing of Complex Molybdenum Ores

Modern trends in technological improvement for producing high-quality rhenium-containing molybdenum concentrates are aimed at developing environmentally friendly solutions com-pared to traditional ones, involving a reduction in consumption or complete replacement of toxic substances and the use of plant reagents and microorganisms and make it possible to eliminate energy-intensive processes of steaming and roasting. It is known that up to 25%–30% of Mo, Cu and Re goes to rough flotation tailings and is lost in wastes. Those losses are a consequence of the ore composition variability, chalcopyrite–molybdenite ratio, an increase in the proportion between primary copper sulfide and finely disseminated molybdenite and the recovery of floating pyrite. High rates of valuable metal recovery into bulk concentrate can be achieved by using new compositions of flotation reagents that selectively change the hydrophobic properties of the target minerals. The application of new reagent compositions, including novel chemicals—dithiopyrylmethane (DTM), composite reagent (CR) and conventional butyl xanthate (ButX)—was theoretically and experimentally substantiated for the effective rhenium extraction in the processing of hard-to-beneficiate complex molybdenum ores. It is identified that DTM forms a complex DTM–Re compound and chemically adsorbed on rhenium-containing molybdenite providing an increase in Re recovery into the bulk Cu–Mo–Re concentrate by 17%, reducing by two times the loss of rhenium with flotation tailings, and the subsequent 97.6% Re extraction of the molybdenum concentrate by autoclave leaching.

Геохимические особенности Ag-Au рудопроявления Кыплатап (центральная Чукотка)

The article considers the geochemical features of unconventional mineralization in secondary quartzite’s of the Kyplatap ore occurrence, located on the southeastern flank of the volcanic dome structure (VDS) of the same name, complicating the Palyavaam-Pykarvaam volcanotectonic depression (VTD) in the Chaun zone of the Central Chukotka sector of the Okhotsk-Chukotka volcanic Belt (OChVB). The Kyplatap VDS was formed due to the intrusion into the Late Cretaceous Alkaquun volcanites of a large laccolith-like subvolcanic body composed of rhyolite-trachyriolite-trachydacites. Based on the geochemical studies of the Kyplatap ore occurrence, the authors compiled a representative database of geochemical data, including the results of analyses of express-RFA, PKSA and XSA with coordinates and composition of ores and rocks. Correlation analysis of the database showed a positive relationship between Au and Ag, as well as Sb for ore mineralization, and a negative correlation of these elements with the association of the rock group of elements (Ti, Y, Zr, Nb and Yb) that were removed during ore formation. The authors also distinguished the second rock group of elements (K, Ga, Sn, Ba, V, W, Pb, Sc, La and B), characterized by medium and weak correlation of the first group of elements. They calculated the coefficients of enrichment and deficiency of ore-forming elements for the samples taken within the ore zones of the Kyplatap ore occurrence. The extreme enrichment group includes elements Au, Ag, Sb, Bi, As, the average contents of which are 100 times or more, and the minimum concentrations are at least 2-10 times higher than the average contents in the upper crust. The normal enrichment group includes elements S, Sn, Cu, Zn, Mn, Mo and Pb, the average contents of which are 2-10 times, and the maximum concentrations are 5-100 times higher than the average concentrations of the upper crust. The obtained values of the enrichment coefficients indicate a sufficiently intensive metensomatoses and ore formation within the Kyplatap ore occurrence.

Geology and ore composition studies of Dulaan khar uul poly metal deposit

Dulaan khar uul deposit is situated in the NW of the Deluun-Sagsay metallogenic zone, identified within Devonian rift-like structure of Western Mongolia. As for geologic settings, it consists of Devonian Baast uul, Otog formation bimodal volcanic, sedimentary, tufogenic rock units and spatially and genetically interrelated subvolcanic units. The poly metal mineralization develops lenses, layers and vein-like bodies within NE-SW-directed quartz-sericite metasomatite zones extending 700m in length and 300m in width. As a result of geological survey there are identified totally five ore bodies and three of which (id no. I, II-1 and II) are exposed at the surface while the ore bodies no. III and IV are concealed. The ore body no. I continues 600m in extension and dips into the west with an angle of 48-72o. As well, along the dip it extends up to 210m and ranges from 1.33m to 12.2m in width; the oxidation zone is approx.50m in thickness. The ore body no. II contains most of the ore resources and marginally converges into the depth of 50-100m. It also shapes like lenses with dipping angle of 36-87o to the west and occurs in 600m in length extension along strike and extends 350m along dip; the thickness ranges between 0.5m and 18.0m. The ore body no. II-1 exists between the ore bodies no. I and II and is 350m in extension along strike direction and up to 300m along dipping. This vein-like body extends with dipping angle of 51-73o; the thickness ranges from 0.5m to 19.3m. The ore body no. III is concealed in the depth interval of 150-200m below the surface, extends 600m along strike with the thickness of 10.94m. It dips toward the NW with dipping angles of 45-70o as split veins and plates. The ore body no. IV is in 350m in strike length extension and 80m along dipping. The thickness is between 1.15m and 18.3m. The mineral composition of the deposit ore is characterized by mainly sphalerite and galena with pyrite, slight amount of chalcopyrite, occasionally tennantite, marcasite, ilmenite, cerussite, smithsonite, hematite, malachite, arsenopyrite, siderite, gold etc. Two types of sphalerite are identified: (Zn, Fe)S, marmanite with iron and (ZnS) native zin sulfide cleiophane.

Secondary minerals of Fe, Pb, Cu in sulfide-containing tailings: sequence of formation, electrochemical reactions and physico-chemical model (Talmovskie Sands, Salaire, Russia)

The results of studies of the composition and form of secondary minerals Fe, Pb, Cu, formed under contrasting physico-chemical conditions of the accumulated tailings from the enrichment of barite-polymetallic ores of the Salair ore field, are presented. The complex mineral composition of ores (pyrite, chalcopyrite, sphalerite, galena, fahlore) and long-term processes of chemical weathering of the substance contributed to the formation of monomineral and zonal secondary rims and fillings of the intergranular space, which were identified using modern research methods. Plumbojarosite, anglesite, cerussite, and iron hydroxides predominate among them; pyromorphite, ginsdalite, and covellite occur less frequently. The method of thermodynamic modeling was used to solve the inverse problem - the restoration of the composition of solutions that led to a change in the associations of secondary minerals. The nature of the ongoing processes can be characterized not only by chemical interactions, but also by electrochemical reactions in the systems under consideration, where various mineral components act as galvanic pairs, which, in combination with the physico-chemical parameters of the medium (pH, Eh, ionic composition of solutions ), leads to stepwise or incomplete oxidation of the original minerals with subsequent selective deposition of secondary compounds.

Process Mineralogy Automatic Detection System in Research of a Gold Polymetallic Mine

Automatic process mineralogy detection system has been widely used in beneficiation process parameters detection, cause finding, and defect diagnosis in concentrators. A gold ore composition in Shandong is more complex, and recovery is difficult. To clarify the ore properties, mineral composition, main minerals, embedded characteristics, and monomer dissociation characteristics, the scanning electron microscope, BPMA, and energy spectrometer are used for the ore sample process mineralogy research to provide a reliable basis for the study of the selection process. The research shows that the main valuable elements in the ore are gold and copper, copper and gold symbiotic ore. Meanwhile, the gold, copper, and iron-containing minerals are closely embedded, pyrite and magnetite are the main minerals for sulfur recovery, and magnetite and limonite are the main minerals for producing iron concentrate. Automatic process mineralogy has played an important role in determining the selectability research and beneficiation process of the polymetallic gold ore.

Геохимические особенности и зональность залежи Филизчайского колчеданно-полиметаллического месторождения (южный склон Большого Кавказа)

The article discusses the geochemical features and zoning of the ore deposit of the Filizchay deposit on the southern slope of the Greater Caucasus. The spatial distribution of valuable (Cu, Zn, Pb) components, their sum, as well as the distribution of Ag, which have a high content for the Filizchay deposit, are considered. A field model was built on the basis of the Leapfrog GEO program. In order to quantify zoning, the index of geochemical zoning was calculated based on the ratios of the concentrations of elements accumulated in the upper part of the ore deposit (Zn, Pb, Ag) and elements accumulated in the lower part of the deposit (Cu, Co, Mn). It has been established that in the Azerbaijan part of the southern slope of the Greater Caucasus, as we move from the northwest to the southeast, there is a regional ore zonality, expressed in the change of chalcopyrite-pyrrhotite ores by sulfide-polymetallic ones, as a result of which there is a decrease in the concentration of copper and, accordingly, an increase in the amount of zinc and especially lead. According to the degree of intensity of manifestation of zinc, lead and silver mineralization in the deposit, two parts can be distinguished: the western one is richer, where almost all the maxima are concentrated, and the eastern one is poorer, which accounts for most of the minima. Additional exploration work is recommended in the eastern part. The distribution of elements in individual wells established a clear zoning in terms of the thick ness of the ore deposit, manifested in a regular change in the mineral and chemical composition of ores from a lying to a hanging side. This leads to the accumulation of copper, cobalt, tin and manganese in the foot, and the concentration of zinc, lead, cadmium, thallium, mercury, antimony, etc. in the hanging side of the ore deposit.

Tectogenesis as a factor influencing the stability of rock masses of the Northern iron ore district of the Kryvbas


 
 
 In the Northern iron-ore district of the Kryvbas basin, mining of deposits of poor magnetic ores is underway in two quarries – Pervomaiskyi and Hannivsky. Oftentimes, their mine contours contain low-valuable or unusable magnetite-silicaceous quarzites of containing ferrous and slate horizons. As a result, excavated ore mass contains ores and partly containing rocks of various mineral and chemical compositions and physical and technical properties. This caused diversity (15 mineral kinds) of the compositions of ores mined from the both deposits. Variability of mineral compositions of ores and rocks is due to manifesta- tions of numerous geological processes such as sedimentation, metamorphism, tectogenesis, metasomatism, supergene, etc. Various mineralogical, geochemical courses of the processes resulted in variability in physical, technical characteristics of ores and containing rocks, and this, in turn, caused various stability of rock masses during drilling-explosive works and mining. Stability of pit walls of the quarries of iron-ore deposits of the Kryvyi Rih basin is a sharp issue for mining enterprises. Solutions to those issues have been analyzed in various aspects. A number of factors take effects on the indicator of stability of rock masses within deposits, particularly mineralogical, geochemical, tectonic, etc. This paper looks at the influence of the tectonic factor specifically, which actively manifests within the Pervomayskyi and Hannivskyi deposits as fractures, breccias, mylonite of ores and rocks. During the surveys, there were designated tectonically altered kinds of ores and rocks within the both deposits, which take effects on seismic stability of pit walls of the both quarries, and also we put areas with various tectonic intensities on schematic maps. For this purpose, we used geological methods of study (selection of samples, mapping), mineralogical (determining quantitative proportions of minerals, texture, structure of ores and rocks). The study provides the data of mineralogical estimates of tectonically altered types of ores and rocks of productive layers of the Pervomaiskyi and Hannivskyi deposits of the Kryvyi Rih basin. We charted maps with areas of various manifestations of tectonic changes within productive layers of the both deposits.
 
 

Geological structure and gold prospectivity of the Shamansky ore cluster of the Altai-Sayan folded region (Republic of Khakassia)

In this work, we consider the geological settings, mineralogical composition and age of rocks and ores, as well as regularities in the formation of gold mineralization of the Shamansky ore cluster, which is one of the most prospective ore clusters in the Altai-Sayan mineragenic province. It is shown that the cluster has a complex fold-block structure. The rocks are characterized by intense folded and discontinuous dislocations. We identified the area of the reatest deformations, where the known prospective signs of gold mineralization are concentrated. Two morphological types of gold-sulfidequartz ores have been distinguished: veins and pyritequartz-sericite-ankerite metasomatite. We characterized the composition of gold and its morphological features. Sulfur isotope data of sulfides from gold-bearing quartz veins predominantly have values of δ34S from +3.7 to+6.5 ‰ that indicate their hydrothermal-sedimentary origin. 40Ar/39Ar isotope-geochronological data on sericite from gold-bearing quartz shows the age of 359.5 ± 5.5 Ma testifying to the Late Devonian-Early Carboniferous stage of the formation of gold-sulfide-quartz veins. A comparison of geological, metallogenic, mineralogical-geochemical and isotope-geochronological data allowed us to conclude that the gold mineralization of the Shamansky cluster belongs to the orogenic type. According to the model of formation, gold mineralization occurred in three stages: ore-preparation islandarc (540-520 Ma), main ore orogenic-1 accretion-collisional (510-450 Ma), and additional ore orogenic-2 transpressional-collisional (380-345 Ma).

Geological features and genesis of the Dyusembay Central (Sayakhat) ore deposit

The article considers the geological features and ore composition of the Dyusembay Central (Sayakhat) leadzinc deposit in the Karsakpai metallogenic complex in the Central Kazakhstan. Historically, the complex was considered industrially significant in terms of iron ores, rather than of lead, zinc, and copper. It is shown that the ore deposit is composed of tuffaceous, silty-sandstone, carbonaceous-terrigenous (ore-hosting), terrigenous, and volcanogenic rocks assigned to the lower subformation of the Zhilandysai Formation of the Upper Proterozoic. The subvolcanic rocks identified and outlined in the area of the ore deposit belong to vent volcanic facies and are represented by felsic automagmatic breccias. All the rock complexes developed within the deposit have undergone multiple alterations: the regional, postvolcanic, contact, and hydrothermal (near-ore) ones. Commercial ores are represented by veinlet-disseminated sulfide mineralization in carbonaceous mudstones and silty sandstones, regionally and metasomatically altered to varying degrees. The ore bodies are composed of heterogeneous mineral assemblages corresponding to various stages and phases of the ore formation. The composition and structural and textural features of the ores reflect the long and complicated history of their formation. It is concluded that this ore deposit belongs to a new formational type of veinlet-disseminated stratified lead-zinc deposits localized in black shale sequences, with a significant role of volcanic activity and regional metamorphism, and is a remobilized SEDEX-type ore deposit.

Study of gold-bearing ore bonification ability

The paper presents the study results on the gold benification and increase of gold extraction in the flotation cycle of ore from the Vasilkovsky deposit. The composition of the initial ores was studied. Based on mineralogical, XRF, chemical assay, atomic absorption, X-ray phase and rational analyses the following types of gold were identified: fine gold; gold associated with sulfides in chalcopyrite, pyrite and arsenopyrite; and fine-disseminated gold in silicates. It was established that the ore belongs to the gold-quartz and gold-sulfide types with free and cyanided gold. Our results allow us to optimize the ore flotation reagent mode and the crushing size class. Butyl xanthate was used as a collector; C7, aeroflot, was used as a foaming agent; sodium sulfide (Na2S) was used as a sulfidizer; dispersion mode was additionally applied. It was established that an increased pH value of the initial pulp up to 9,0 is required to boost the efficiency of flotation beneficiation. The gold extraction in the concentrate is 82,49 %. This experiment and mineralogical analysis of flotation tailings has established the optimal fineness of the fractions for flotation (0,1 +- 0,071 mm) as well as the inexpediency of additional milling, due to the fine free and quartz-embedded gold that does not pass into the concentrate during the subsequent flotation. The mineral analysis of the flotation products showed that the main sulfide mineral of the concentrates is arsenopyrite; pyrite and chalcopyrite. Flotation tailings contain host vein rock. Gold found in flotation tailings samples has round and oval shape, which is inefficient for flotation.

Extraction of Low-Dimensional Structures of Noble and Rare Metals from Carbonaceous Ores Using Low-Temperature and Energy Impacts at Succeeding Stages of Raw Material Transformation

The possibility of extraction of metals from ores of different genesis, containing low-dimensional structures of rare and noble metals, increases their commodity value and, in a deficit for some types of metals, leads to the need to search and develop new nature-like technologies, which can be used to extract from ores of different genesis almost all valuable noble, rare earth and nonferrous metals regardless of their concentration. This article presents the results of studying the processes of comminution and flotation to extract low-dimensional structures of noble and rare metals from carbonaceous ores using low-temperature and energy impacts at successive stages of the ores’ transformation. With the use of modern mineralogical, physical and chemical methods of research of composition, structure and properties of ores, the initial samples, concentrates and tailings after enrichment were studied. During the study, it was established that the difficulty of extraction of strategic metals from carbonaceous hard-enriched ores consists in fine dissemination of valuable components in concentrator minerals, mutual penetration of ore mineralization into each other and into rock-forming minerals, and in proximity of physical, chemical and technological properties of minerals, which complicates selective extraction of valuable components in concentrates. Also, difficulties in enrichment are associated with high flotation activity of waste rock, which significantly reduces the quality of concentrates.

Mine Air Makes Free? Rural Liberty, Materiality, and Agency in Europe’s Long Thirteenth Century

Abstract Mines and miners began to proliferate in Europe from the late twelfth century on, in lockstep with the region’s accelerating economic integration and urbanization. Mining communities were often rural and remote, reflecting landlords’ capacity to attract workers through freedoms that echoed the era’s incentives for urban migration. If, according to the adage, “city air makes free,” so apparently did the mine. Yet the specific affordances of mines’ materiality, and the mobility regimes they fostered, shaped distinct social dynamics. These emerge in their complexity when mining ordinances—a new type of legal subgenre—are explored for their handling of matter and movement. Mining legislation attests that the composition of ores, the underground extension of seams, the quality of available tools, and the behavior of gas, water, and air across different topographies were salient factors over which elites had little control. The raw physical constraints on directing the flow of people and matter into, through, and out of mines thus created a network of subterranean agency that translated under certain conditions into exterranean power.

Features of the mineral composition of ores in the oxidation zone of the Okzhetpes ore field (on the example of the gold mining area “Ore Zone No. 3”)

The discovery of new deposits every year becomes more difficult, since promising areas are located at a relative depth, are characterized by more complex mining and geological conditions and smaller sizes. In addition, these new areas are overlain by younger formations, where intense supergene processes are often developed, which require other more advanced methods of forecasting and estimating hidden positions. The Okzhetpes antiform in the core is composed of carbonate rocks (limestones, dolomites) of the Devonian-Carboniferous age of the structural-material complex (SMC) Murun, and on the wings - overlying terrigenous rocks of the Early Paleozoic. Previously, many studies of the oxidation zone of Western Uzbekistan were considered from the point of view of the search for bauxites, zeolites and other mineral resources. Mineralogical studies of recent years are aimed at assessing the gold content of the oxidation zones. The article considers the materials obtained by the authors in the study of the mineral composition of the ores of the gold ore area "Ore zone No. 3" of the Okzhetpes ore field. The processes of desulphurization, the behavior of finely dispersed gold, which are in the composition of ores, are disclosed. The obtained research results confirm that the predominant part of gold remains in the minerals replacing sulfides (pyrite, arsenopyrite) with the preservation of gold and its characteristic companions in the products of sulfide oxidation (hedrogoethite, goethite and scorodite).

Analysis of the Elemental Composition of Four Bronze Sickles Dated at the Late Bronze Age

The present study presents the analysis of the elemental composition of four bronze sickles, three with hooked handle and one with holes on the handle, two from the deposit at Valea lui Darie, Vaslui county, one from the bronze deposit at Ciorani, and one discovered in a dwelling from the settlement belonging to the Noua culture from Dodești, following systematic archaeological research. The sickles from the Valea lui Darie deposit belong to the Ghermănești type, the Ghermănești variant, the Ciorani sickle to the Ilișești variant of the Ghermănești type, and the Dodești sickle to the Heleșteni type. These types of sickles are characteristic for the Late Bronze Age east of the Carpathians, being chronologically placed between XII – X BC. The elemental composition of the four pieces was identified by employing non-invasive analysis with a mobile spectrometer, Thermo Niton XL3, resulting in a composition of a binary copper-tin alloy (Cu-Sn), to which a number of secondary elements are added: arsenic, antimony, iron, nickel, lead, titanium, and sulphur. In the case of the sickle from Dodești, the percentage of lead is 1.593% which could come from the composition of the copper or tin ores used, given that the percentage should be higher than 2-3% to be considered an intentional addition. Arsenic was also identified in the composition of the four sickles, but in small percentages, > 1%, most likely coming from the composition of the copper ore used. The elemental composition of ancient artefacts enables the establishment of correlations between different types of objects, production areas, raw material resource areas, and distribution patterns. Based on the elemental composition, the four sickles fall into the group of copper objects with arsenic, antimony/antimony, and nickel as the main secondary elements.

BACTERIAL LEACHING OF BALANCED ORES OF ALBITITE DEPOSITS OF THE UKRAINIAN SHIELD

Prospects for increasing the raw materials resources of uranium ore deposits of the albite formation of the Ingul megablock of the Ukrainian Shield and the possibility of reducing the impact of harmful waste due to the method of bacterial leaching of metals were considered. Mineral-forming systems of uranium-bearing albitites of the Ukrainian Shield have always been considered as monoelement, exclusively uranium objects. However, their out-of-balance ores and tailings contain elevated, up to industrial, concentrations of other metals, which, under conditions of hypergenic processes, pose a potential threat of environmental pollution. In order to determine the possibility of expanding raw materials resources of albite deposits of the Ukrainian Shield due to the use of the method of bacterial leaching of metals, the composition of industrial ores and host rocks was considered. In particular, our data from their mineralogical and geochemical research showed that uranium and five of its companion elements: thorium, vanadium, beryllium, zirconium and lead reach industrial content. At the same time, cobalt, nickel and zinc are characterized by an increased content close to the minimum industrial values. The most promising for bacterial leaching are rocks that contain sulfides. The rocks of the uranium ore albitite formation contain sulfur-containing compounds and, in particular, pyrite, as well as bi- and trivalent iron. We found the highest content of sulfides in albitized rocks (up to 0.82%), ore-free albitites (up to 0.81%), low-ore albitites (up to 0.61%), that is, in rocks accumulated in industrial waste. It is assumed that the use of bacterial leaching methods with the participation of chemolithotrophic microorganisms can be promising for the processing of off-balance ores and will contribute to the expansion of the raw material base of albite deposits of the Ukrainian Shield, due not only to uranium, but also to nickel, cobalt and zinc.

Composition and formation conditions of noble metal ores of the Koykar-Svyatnavolok sill (Republic of Karelia)

The Viksha iron ore deposit is confined to the Koykarsko-Sviatnavolok sill, where as a part of ore bodies, in addition to the main components - iron and titanium, it contains gold, platinum, and palladium. The purpose of this publication is to determine the type and patterns of noble metal mineralization in gabbro-dolerites of the Koykar-Svyatnavolok sill, to consider the mechanisms of accumulation and localization of precious metals in ore bodies. The repeated occurrence in the section of the intrusion of an association of two rock varieties of contrasting composition (high-iron - titanomagnetite gabbro-dolerites, and high-siliceous - granophyres), as well as the revealed petrographic, petrochemical and geochemical regularities, allow us to consider liquid stratification of magmatic melt as a mechanism for the formation of ore titanomagnetite horizons ( segregation). This liquid immiscibility led to the accumulation of noble metals in the high-iron fluidized liquate in accordance with distribution coefficients of nobel metals between silicate and oxide melts and between melt and fluid. The confinement of noble metal mineralization to sulfide, cobaltite-bornite-chalcopyrite accumulations in ore titanomagnetite horizons has been established, which corresponds to the low-sulfide noble metal type of mineralization. Precious metal mineralization is represented by both native mineral forms (arsenides, sulfoarsenides, antimonides and intermetallides of platinum group metals, gold and silver tellurides, electrum, native gold) and isomorphic impurities in bornite and cobaltite. The relationship between the formation of minerals bearing noble metals and the process of chloritization against the background of the transformation of protolith titanomagnetite is shown. A model for the concentration of precious metals from basaltoid melt in several stages is proposed: enrichment of fluidized high-iron ore liquat with precious metals; their accumulation in the residual fluid and in the sulfide liquid during the crystallization of ore liquat; their partial entry into the hydrothermal solution during fluid cooling and hydrothermal metasomatism of earlier crystals. The localization of noble metals occurred as the residual fluid cooled, due to the destruction of complex chloride and sulfide compounds with noble and non-ferrous metals and the crystallization of sulfide-precious metal paragenesis within the ore horizons.