Online first

The use of stage-wise schemes in the development of deep quarries is one of the ways to increase the economic efficiency of mining a deposit and determining the optimal stage parameters remains an urgent task. Such parameters are stage depth, bench height, block length, etc. However, there is a wide range of values for these parameters. Therefore, to select the optimal values and evaluate the effectiveness of design solutions, it is advisable to use the net present value, which is an international notion. As a result of the analysis of data on deposits, a large number of variable indicators can be identified that presumably affect the efficiency of mining. The article proposes to divide all parameters of the quarry mining into two types: mine engineering and economic. The importance of each of them is determined by the measure of influence on the net present value. Thus, to assess the measure of influence of mining indicators, the average values of each of them are taken, and as a result of the alternating change of one parameter under study, the measure of its influence on the discounted income received is estimated. The results of the analysis of relevant factors, their evaluation and comparative analysis are important indicators that significantly affect the design decisions made and the effectiveness of the investment project.

The Arctic shelf zone is an important research target due to its significant hydrocarbon potential. A study of the physical properties (density, elasticity, elastic anisotropy index, specific acoustic impedance, and porosity) was conducted for core samples from six wells in the South Barents Basin: Admiralteyskaya-1, Krestovaya-1, Ludlovskaya-1, Shtokmanskaya-1, Arkticheskaya-1, and Severo-Kildinskaya-82. The sample collection consists of sandstones, siltstones, and limestones. Core analysis revealed that rocks from non-productive wells (Arkticheskaya-1, Admiralteyskaya-1, and Krestovaya-1), located in the central part of the South Barents Basin and within the Admiralty High, differ in their physical and petrographic properties from rocks in gas and gas-condensate wells (Shtokmanskaya-1, Severo-Kildinskaya-82, and Ludlovskaya-1), located near the boundaries of the South Barents Basin. Core samples from productive wells (Shtokmanskaya-1, Severo-Kildinskaya-82, Ludlovskaya-1) exhibit lower average P-wave velocities, lower specific acoustic impedance, and higher open porosity and/or elastic anisotropy index compared to non-productive wells (Arkticheskaya-1, Admiralteyskaya-1, Krestovaya-1). This combination of petrophysical parameters provides the reservoir properties of rocks prospective for hydrocarbons. The petrographic variation of the reservoir properties of the studied rocks from productive to non-productive wells is associated with a decrease in grain size and a transition from pore-filling cement to thin-film and basal cement. The sandstones from the Shtokmanskaya well have a larger grain size (0.1-0.5 mm), whereas the sandstones from the Arkticheskaya-1 and Krestovaya-1 wells are finer-grained (0.1-0.2 mm). The Shtokmanskaya-1 well is characterized by pore-filling cement, the Arkticheskaya-1 ‒ by thin-film cement, and the Krestovaya-1 ‒ by cement of the basal type. The established physical properties of sedimentary rocks, suitable for the development of productive strata, will allow for the screening out of empty areas at the preliminary stage of analyzing geophysical materials during the search for geological and tectonic structures prospective for hydrocarbon accumulations.

This study investigates unique weathering crust samples from the most altered sections (30-43 m) of the weathering profile within the Souktal Plutonic Complex, Northern Kazakhstan. The samples, obtained from two drill cores, consist of quartz, kaolinite, microcline, muscovite, and plagioclase, as identified through polarized light microscopy and confirmed by X-ray diffraction analysis. Sequential extraction of rare earth elements (REE) was performed using inductively coupled plasma mass spectrometry (ICP-MS) following a two-step leaching procedure with hydroxylamine hydrochloride (0.2 mol NH₂OH·HCl) and sodium hydroxide (1 mol NaOH) solutions. The extraction process effectively recovered REE, indicating their presence in an ion-exchangeable form, with total extraction rates (REE + Sc + Y) ranging from 4.1 to 7.8 ppm. The total light REE content varies from 3.5 to 5.9 ppm, while heavy REE content ranges from 0.2 to 0.7 ppm across all samples. Petrological and geochemical analyses suggest that the studied area represents an ion-adsorption-type REE weathered deposit. These findings enhance the understanding of ionic-adsorbed REE within weathering crusts and highlight the effectiveness of sequential extraction methods for REE determination. Moreover, the study suggests that this area holds promising potential as a future REE ion-adsorption site, contributing to the development of Kazakhstan’s national REE industry.

The article is devoted to the actively developing area of wastewater treatment – Constructed Floating Wetlands (CFW, floating bioplatforms). The paper explores the creation history and operational experience of CFW in Russia and abroad. It describes the designs and preferred compositions of substrates and plants for creating phytomodules, paying special attention to the use of natural minerals and the selection of local macrophyte plant species. The CFW technology is suitable for treating various types of wastewater, including inorganic effluents from mining enterprises. The research examines the results of applying phytotechnology for wastewater treatment for pollutants (total nitrogen and phosphorus, organic matter, suspended particles, heavy metals, sulphates, boron, etc.). The article shows successful practices of using CFW for acidic drainage effluents, which are the most challenging for phytotechnology application. The study identifies key factors affecting pollutant removal efficiency – water depth, flow rate, coverage area, aeration, and temperature. The research presents methods to enhance the depth of water treatment at low temperatures. It also notes the positive impact of floating bioplatforms on the condition of water bodies where they are located. The study provides cost estimates for applying CFW technology for wastewater treatment and gives recommendations based on the experience of implementing the technology at a settling pond of a mining enterprise in the Murmansk Region.

Migmatized gneisses of the Chupa paragneiss Formation in the Belomorian Mobile Belt (BMB) of the Fennoscandian Shield have been studied, and the conditions of partial melting during high-grade metamorphism of the rocks were determined. The melting temperatures and pressures, the amount and composition of the melt formed during the anatexis of gneisses in a closed system, were assessed through direct thermodynamic computer modeling of mineral formation and the construction of pseudosections in pressure-temperature coordinates. The mineral formation calculations are based on the principle of Gibbs energy minimization and were performed using the PERPLE_X software package. The bulk compositions of the migmatized rocks from the Chupa Formation, previously classified and grouped based on their major components, were used for the calculations. It is shown that water-saturated partial melting of compositionally diverse gneisses produces granitic or granodiorite-tonalitic melts within a temperature range of 680-730 °C at moderate to moderately high pressures. The study reveals that the key factor controlling the appearance of kyanite in the investigated rocks is a high Al₂O₃/CaO ratio (at least 5:1) in the protolith, combined with a total alkali content (Na₂O + K₂O) exceeding CaO. According the Chemical Index of Alteration (CIA), the protoliths of the gneisses contained detrital material of varying sedimentary maturity. The source rocks were likely weakly to moderately weathered. U-Pb ID-TIMS dating of monazite from two samples of garnet-kyanite-biotite migmatite (whole-rock analysis) indicates Paleoproterozoic migmatization of the Chupa gneisses at 1854 ± 5 Ma. This phase of Paleoproterozoic endogenic activity is widely recorded in the BMB and may be associated with the formation of the Lapland-Kola or Svecofennian orogens, located to the northeast and southwest of the belt, respectively.

Fluorine‑containing wastewater is one of the main problems of the mining and processing industries. Mining, dressing, and sulphuric acid digestion of apatite concentrate – all these processes are accompanied by the generation of vast amounts of wastewater with elevated fluoride content, which pose a serious threat to the environment. Conventional methods do not always allow achieving the required discharge standards, which in turn necessitates the search for alternative reagents. The main objective of this work is to assess the possibility of using waste from the mining and smelting sector (phosphochalk, magnesia scrap, dust from gas cleaning units) as precipitating reagents for the first stage of fluoride ion removal, followed by tertiary treatment with complex titanium‑containing coagulants. We conducted experiments to select reagents and their dosages, the use of which will allow achieving the lowest residual fluoride concentrations in water. We found that using calcium/magnesium hydroxides does not allow meeting the standards for residual fluoride anion content. To achieve maximum precipitation efficiency, a 30 % excess of precipitating reagents is required. The study confirms that large‑volume mineral waste can serve as precipitating reagents for fluoride ion, with treatment efficiencies of 94 % for phosphochalk, 90 % for magnesia refractory scrap, and 99 % for gas cleaning units. We proved the effectiveness of complex titanium‑containing coagulants for water defluorination in comparison with conventional coagulants (aluminium oxychloride/aluminium sulphate). The use of a complex reagent not only significantly reduces coagulant consumption and minimizes residual fluoride anion content, but also substantially intensifies precipitation (by 1.5-1.75 times) and filtration of coagulation sludges (by 1.25-1.5 times). The developed conceptual diagram for wastewater defluorination using large‑volume waste and complex titanium‑containing reagents allows significantly reducing the level of negative environmental impact and taking a step towards implementing the circular economy concept.

С усложнением электротехнического оборудования горных предприятий актуализируются разработка и исследование способов повышения надежности технических устройств, входящих в систему электроснабжения. Статья посвящена оценке параметров надежности схем участков цеховых сетей горных предприятий с однотрансформаторными подстанциями 10 и 0,4 кВ и различными способами их резервирования. Цель исследования – проведение оценки параметров надежности различных способов резервирования схем электроснабжения объектов с трансформаторными подстанциями на среднем и низком напряжении (СН и НН) относительно электропотребителей распределительного устройства низкого напряжения горно-добывающих предприятий. Объектом исследования является система электроснабжения цеха вспомогательного производства горно-добывающего предприятия (Кемерово). В работе исследуются параметры надежности участков сети – вероятность безотказной (исправной) работы P(t), вероятность появления отказа Q(t), параметр потока отказов ω_схемы и время наработки на отказ Т_{нар.отк} для следующих вариантов схем: без резервирования; с резервированием на СН; с резервированием на НН; с двойным резервированием (на СН и НН). Данные расчетов показывают, что время наработки на отказ для схемы без резервирования в 2,04 и в 2,11 раз меньше, чем для схем с резервированием на НН и на СН соответственно, и в 2,8 раз меньше, чем для схемы с двойным резервированием. Резервирование является технически и экономически обоснованным методом повышения параметра P(t) системы электроснабжения объекта. Полученные результаты могут быть интегрированы в проектирование систем электроснабжения объектов (для оптимизации структурной схемы и выбора рационального способа резервирования элементов); разработку программ технического обслуживания (для формирования обоснованных регламентов технического обслуживания и ремонтов); создание систем мониторинга надежности (для организации непрерывного контроля текущего состояния оборудования цехов горных предприятий).

The issue of reducing electricity consumption costs is becoming relevant for industrial enterprises, taking into account the growing demand for electricity every year. The electricity consumption of air coolers at a gas processing plant was considered in the framework of this study. The change in ambient temperature (during the day and depending on the season) is the main disturbing factor affecting the performance of air coolers. With such significant seasonal changes in air temperature, its density changes, which causes fluctuations in the power consumed by the electric motor by up to 30 %. The issues of increasing energy efficiency, forecasting and determining the power consumption rate of air coolers, depending on changing external conditions, therefore become important. A methodology has been developed to determine the standard power consumption of air coolers depending on two factors – the ambient temperature and the load of the gas processing plant. A two-factor power-law approximation of the values was carried out due to nonlinear dependencies on plant loading and ambient temperature. The dependence of power consumption on ambient temperature and the loading of the installation on raw materials for any type of air cooler is determined with high accuracy (the root-mean-square error of the calculated and approximating values does not exceed 1 %). The formula for calculating the standard consumption of electric power of the air cooler at the considered installation was determined based on the results of the study. The methodology can be used by employees of gas processing enterprises to determine the standard electricity consumption of air coolers under changing climatic and technological factors.

The main stages within the chemically active history of diamond genesis are proposed, from the upper-mantle chambers to the explosive ejections of diamonds and kimberlite material from cumulative centers to the surface. The paper focuses on the pre-final episode of diamond deposit genesis – the interaction of diamonds with carbonate-silicate kimberlite magmas in a crustal cumulate chamber. Such interactions are possible when the transport of diamonds by these magmas from the depths of the mantle primary chambers to the surface is stopped within crustal rock complexes with a strong roof. The cooling and solidification time of kimberlite melts in such cumulative centers is long enough to cause a significant mass loss of dissolving diamonds. The interaction of carbonate-silicate kimberlite melts with varying carbonate content with natural single-crystal diamonds was studied experimentally at a pressure of 0.15 GPa and a temperature of 1200 °C. Model carbonate, carbonate-fluid, natural kimberlite, and kimberlite-fluid systems were used as solvents. At experimental conditions, the solvents melted, and diamond crystals surface were underwent by dissolution. It was established that etching patterns are recorded on the growth planes, and diamonds lose mass: from 3-4.5 % after 2-hour exposure (the order of kimberlite transport time from the upper-mantle diamond-forming centers to the crustal cumulative centers) to 47.6 % after 10-day exposure (at the crustal cumulative center conditions). The results demonstrate that the dissolving ability of carbonate-silicate transport magmas is a factor that effectively reduces the diamond potential of kimberlite deposits.