The scientific journal “Mining Bulletin of Uzbekistan” publishes research results in the fields of mining engineering, geology, mineral resource extraction, mineral processing, metallurgy, rock geomechanics, and the application of digital technologies in the mining industry. The journal includes research articles, analytical reviews, and innovative studies prepared by national and international scholars and specialists. ISSN: 2181-7383 DOI: 10.70769/2181-7383.MBU
Navoiy davlat konchilik va texnologiyalar universiteti
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HYDROMETALLURGICAL PROCESSING OF EAF DUST: ZINC EXTRACTION AND RECYCLING IRON RESIDUE IN STEELMAKING
Electric arc steel smelting furnace dust (EAP dust) is one of the most problematic waste in modern metallurgy from an ecological and technological point of view due to its high dispersity, high content of zinc, lead, and other associated elements. In recent years, as a result of the increase in the share of zinc-containing secondary raw materials in the metal charge, the amount of this dust has also increased. In this study, a hydrometallurgical method of complex processing of PE PE dust based on sulfuric acid leaching was considered. A spent sulfuric acid electrolyte containing H2SO4 (120-160 g/l) and Zn (30-50 g/l) was used as the solvent reagent. The leaching process was carried out at a temperature of 60-65 °C, in a solid-liquid ratio of 1:6, for 120-240 minutes. The research results showed that zinc-containing phases accelerate the dissolution kinetics, reduce energy consumption, and provide the possibility of effective extraction of zinc from the solution and subsequent obtaining the cathode metal by electrolysis. In addition, it has been substantiated that the iron-containing residue formed after leaching can be re-turned to the steelmaking process as a charge additive. The proposed technology is a resource-saving, energy-efficient, and environmentally friendly alternative to traditional pyrometallurgical methods of processing EAP dust. This approach serves the implementation of the principles of a circular economy through the processing of metallurgical waste, the restoration of zinc, and the return of iron components to production.
Copyright (c) 2026 Ilhamov, M.A., Munosibov, Sh.M., Matkarimov, S.T., Maksudov, S.A. (Muallif) https://creativecommons.org/licenses/by/4.0
APPLICATION OF THERMOKINETIC MODELS FOR PREDICTING THE STRUCTURE AND PROPERTIES OF SHAFT GEARS
This article presents a comprehensive study of the kinetics of phase transformations occurring during the heat treatment of large gear shafts made of 34KhN3MA structural alloy steel. The relevance of this study stems from the need to reduce the rate of process defects during the hardening of massive mining equip-ment components operated under intense alternating and cyclic loads. Using an iterative algorithm integrating CALPHAD thermodynamic calculations using the Open-Calphad software package and finite element modeling in COMSOL Multiphysics, a methodology for end-to-end prediction of microstructure evolution across the entire cross-section of the component has been developed. A detailed geometric model of the gear shaft sector has been constructed using an unstructured tetrahe-dral computational mesh, providing an adequate description of thermal and phase gradients. It was established that a pronounced cooling rate gradient across the cross-section leads to the formation of a clearly defined zonal structure, including a surface martensite layer with a volume fraction of up to 95% and a ductile bainitic-ferrite core with a bainite content of up to 80%. Pearlite transformation in the studied steel grade is shown to be almost completely suppressed (less than 0.5%) due to complex alloying with nickel and molybdenum. Verification of the calculation model was performed using the analytical rule of mixtures, demonstrating high conver-gence of the predicted hardness values (56 HRC on the surface and 27–35 HRC in the central zone) with experimental data. Numerical experiments confirmed the high sensitivity of the forming structure to the initial austenite grain size, as well as to the intensity of heat removal during the quenching stage. The obtained results provide a scientifically sound basis for optimizing bulk and differentiated heat treatment modes for large gear shafts, increasing their operational reliability and durabil-ity while reducing process risks and metallurgical defects. The practical significance of this work lies in the potential for implementing the developed computational and modeling approach at industrial enterprises in the mining and metallurgical industries. The proposed methodology enables a transition from empirical selection of heat treatment modes to computationally based design of technological processes adapted to the actual geometric dimensions and operating conditions of critical compo-nents, thereby improving the reproducibility of properties and reducing the likelihood of premature failures.
Copyright (c) 2026 Egamberdiyev, I.P., Saibov, M.F. (Muallif) https://creativecommons.org/licenses/by/4.0
WAYS TO INCREASE THE RELIABILITY OF HIGH-CAPACITY BAT-TERY BATTERIES
This article presents a systematic and comprehensive analysis of modern scientific and technological approaches aimed at ensuring the reliability, safety, and long-term operational stability of high-capacity lithium-ion batteries. Within the scope of the study, the main degradation mechanisms occurring during battery operation are thoroughly investigated, with particular emphasis on physicochemical processes taking place at the electrode–electrolyte interfaces. The poten-tial for controlling interfacial processes by enhancing the chemical and mechanical stability of protective layers (SEI and CEI) formed on the anode and cathode sur-faces is analyzed. Special attention is paid to optimizing the nanostructured architecture of electrode materials in order to improve ion and electron transport, reduce internal mechanical stresses, and limit deformation arising during cyclic charge–discharge processes. The effectiveness of functional additives that suppress electro-lyte decomposition reactions and enhance stability under high-voltage conditions and sharp temperature fluctuations is evaluated. The article also examines in detail the impact of materials designed for efficient thermal management, active monitoring and diagnostic systems, as well as structural solutions aimed at minimizing heat losses, on battery safety and operational stability. The potential for reducing internal resistance, increasing power and energy density, and improving overall energy efficiency through the use of advanced highly conductive layers and innovative functional materials is scientifically substantiated. The integration of these technologi-cal and materials-science approaches enables a significant improvement in the cyclic stability of lithium-ion batteries, slows down chemical and thermal degradation processes, strengthens safety criteria, and substantially extends battery service life. This study provides a systematic analysis of the key factors affecting battery reliability and proposes effective scientific and technological solutions to mitigate their adverse effects. The main objective of the research is to identify the most prom-ising technological approaches and scientific solutions for achieving stable, safe, and long-term operation of high-capacity lithium-ion batteries under real operating conditions.
Copyright (c) 2026 Murodov, X.Sh., Bozarova, M.B. (Muallif) https://creativecommons.org/licenses/by/4.0
RESEARCH ON THE FUNCTIONAL SCHEME OF ENERGY CON-SUMPTION AND PRODUCTIVITY OF A CONE CRUSHER IN THE MIN-ING INDUSTRY
In industry and construction, ore crushing is one of the most important and costly processes in mineral processing. The quality of its control determines the level of energy consumption not only of mineral processing, but also of subsequent stages, especially in crushing processes, which are the most energy-intensive in the entire production. The size of the crushed ore significantly affects the power consumption of the crushing mills in the subsequent stage. Since the primary crush-ing of the ore is carried out using cone crushers, and its energy consumption process is characterized by a large number of parameters. The cone crusher is a multi-input multi-output system, and since the relationship between the physical and chemical properties of the ore and the crushers is very complex, it is very important to have a description of the multi-factor functional scheme of the steady state of the cone crusher for its quality control.
integrated measurement and control system
Copyright (c) 2026 Mavlonov, J.A., Olimov, J.S. (Muallif) https://creativecommons.org/licenses/by/4.0
SCIENTIFIC JUSTIFICATION OF THE RELATIONSHIP BETWEEN TRANSFORMER VIBRATION ACCELERATION AND ITS REMAINING USEFUL LIFE
From a scientific point of view, the article reveals how dangerous the mechanical vibration that occurs during the operation of oil-fired power trans-formers really is. From a scientific point of view, the article reveals how dangerous the mechanical vibration that occurs during the operation of oil-fired power trans-formers really is. Vibration is not just a "noise" or an external sign - it is considered as a source of serious degradation, which gradually corrodes the mechanical resource of the equipment, reducing its service life. The article clearly lists the causes of head vibration: dynamic impacts caused by a time–unstable electromagnet-ic field, strong electrodynamic shocks during short circuits, shifts and relaxation accumulated in the magnetic circuit and lead blocks during prolonged operation, as well as external mechanical impacts such as impacts during transportation, shaking of the ground or nearby. sources of vibration.Tatiana clearly lists the causes of head vibration: dynamic impacts caused by a time–unstable electromagnetic field, strong electrodynamic shocks during short circuits, shifts and relaxation accumu-lated in the magnetic circuit and lead blocks during prolonged operation, as well as external mechanical impacts such as impacts during transportation, shaking of the ground or nearby. sources of vibration. In the experiments, vibration acceleration was expressed through a sinusoidal model and measured with high-resolution accelerometers. Based on this, the effective acceleration value was determined, as well as the frequency spectrum. When calculating mechanical stresses, the theory of light was applied, and the highest normal and cutting stresses were found in the tube elements.Based on this, the effective acceleration value was deter-mined, as well as the frequency spectrum. When calculating mechanical stresses, the effective acceleration value was used, as well as the frequency spectrum. When calculating mechanical stresses, the theory of light was applied, and the highest normal and cutting stresses were found in the tube elements. These stresses were then linked by empirical links describing the depletion behavior, and “transformed" into the number of depletion cycles. On the other hand, the total damage was estimated using the linear loss accumulation rule, that is, the total wear effect summed up for each load contribution. On the practical side, using the example of a real transformer with a capacity of 20 MVA, calculations were performed for various levels of vibration accelerations (from light to powerful). On the practical side, using the example of a real transformer with a capacity of 20 MVA, calculations were performed for various levels of vibration accelerations (from light to powerful). The result is obvious: as the vibration on the other side increases dramatically, calculations were performed for various levels of vibration accelerations (from light to powerful) using the example of a real transformer with a capacity of 20 MVA. The result is obvious: as vibration increases, mechanical stresses increase dramatical-ly, the fatigue threshold decreases, and the service life is significantly shortened. This dependence is reliably confirmed by numerical tables and graphs. In the end, it was found that the phenomenon of vibration is one of the main factors that “eat up” the real mechanical life of the transformer. On the other hand, the proposed mathematical model and calculation method are recommended as a convenient, scientifically based diagnostic tool for real-time monitoring, preliminary assessment of the remaining service life and planning preventive repairs.
Copyright (c) 2026 Ataullayev, N.O., Tog‘aymurodov, S.Z. (Muallif) https://creativecommons.org/licenses/by/4.0
INTENSIFICATION OF CONTACT HEAT EXCHANGE IN A VORTEX APPARATUS TO IMPROVE THE EFFICIENCY OF WET GAS CLEANING
The article presents the results of a comprehensive experimental study on the intensification of contact heat transfer during the direct interaction of hot water and air flows in a vortex-type apparatus. The relevance of the research is determined by the increasing demand for improved energy efficiency, reduced operat-ing costs, and enhanced environmental safety of thermal and gas-cleaning systems, as well as the transition of industry toward sustainable development principles. The objective of the study is to establish quantitative relationships between hydrodynamic parameters, liquid-to-gas mass flow ratios, swirl intensity, and their influ-ence on the heat transfer coefficient, thermal capacity, and overall efficiency of the apparatus. An experimental setup with tangential injection of both gas and liquid phases was developed and implemented to ensure the formation of a stable vortex regime, an expanded interfacial contact surface, and a high level of turbulence. The experimental data were processed using the Nusselt and Reynolds similarity criteria, together with heat balance equations accounting for evaporation, condensation, and changes in air moisture content. Experiments were carried out over a wide range of Reynolds numbers and L/G ratios, allowing stable heat transfer patterns to be identified. It was established that increasing the gas Reynolds number from 45,360 to 97,253 results in a rise of the Nusselt number from 2,300 to 15,700. Higher irrigation density intensifies heat transfer due to enhanced liquid dispersion and enlargement of the interfacial area. The obtained results can be applied in the design and modernization of energy-efficient vortex heat exchangers and wet gas-cleaning systems.
Copyright (c) 2026 Ahmatov, A.A. (Muallif) https://creativecommons.org/licenses/by/4.0
INTEGRAL THERMOKINETIC MODELING OF STRUCTURAL HETEROGENEITY AND SERVICE LIFE OF LARGE-SIZE STEEL 34KhN3MA SHAFT GEARS
This work presents a comprehensive study of the evolution of the microstructure and mechanical properties of large-scale shaft gears during heat treatment. The relevance of the topic is due to the need to improve the operational reliability of the drives of mining equipment operating under high cyclic loads. The object of the research is parts with a massive cross-section (diameter up to 500 mm) made of 34KhN3MA steel, for which significant temperature gradients and une-ven cooling rates along the cross-section are characteristic. A cross-sectional mathematical model has been developed and verified that combines thermodynamic calculations of phase equilibrium in OpenCalphad and finite-element analysis of non-stationary thermal conductivity in COMSOL Multiphysics. The kinetics of overcooling austenite decomposition during continuous cooling were described using the modified JMAK equation and Sheil's additivity principle. The model takes into account the thermal effect of the phase transition (recalescence) and the transformation-induced plasticity effect (TRIP), which made it possible to predict the critical points of decay with high accuracy. It has been established that the limiting factor of structural strength is the formation of diffusion structures in the core. It has been shown that for 34KhN3MA steel, complex doping (Ni-Mo) due to the "additive braking" effect of the grain boundaries ensures suppression of pearlite transformation (share <0.5%) even in the thermal center of the shaft. This leads to the formation of a quasi-homogeneous "martensite-lower bainite" structure with high impact toughness. Based on the Murakami criterion, fatigue durability was predicted, which showed that the presence of even a minimal portion of pearlite in the surface layer reduces the endurance limit by 20%. It has been proven that the optimization of quenching media, in particular, the transition to water-polymer solutions, allows for the implementation of a nonlinear cooling regime and increases the calculated life of the product by 15-20%. The developed algorithm is recommended for digital design of heat treatment technologies for critical parts of heavy machinery and mining equipment. Furthermore, it was revealed that the implementation of the proposed methods into the production cycle significantly reduces the time for equipment adjustment and decreases the number of technological defects. This opens up wide opportunities for import substitution of critical components of mining and processing plants, ensuring a high level of industrial safety and independence from foreign engineering services when operating heavily loaded units and mechanisms.
Copyright (c) 2026 Saibov, M.F., Ulug‘ov, G'.D., Ashurov, X.X. (Muallif) https://creativecommons.org/licenses/by/4.0
ANALYSIS OF THE THEORETICAL FOUNDATIONS OF CORONA DIS-CHARGE PHENOMENA AND ENERGY LOSSES IN HIGH-VOLTAGE POWER TRANSMISSION LINES
*]:pointer-events-auto R6Vx5W_threadScrollVars scroll-mb-[calc(var(--scroll-root-safe-area-inset-bottom,0px)+var(--thread-response-height))] scroll-mt-[calc(var(--header-height)+min(200px,max(70px,20svh)))]" dir="auto" data-turn-id="request-WEB:ea0abfb9-3e93-43fd-a98f-b6bfdadb22b7-18" data-turn-id-container="request-WEB:ea0abfb9-3e93-43fd-a98f-b6bfdadb22b7-18" data-testid="conversation-turn-38" data-turn="assistant"> This paper investigates the corona discharge phenomenon occurring in high-voltage transmission lines and the associated power and electrical energy losses based on modern monitoring technologies. The main objective of the study is to develop a scientifically grounded monitoring approach for accurately assessing the operational condition of overhead high-voltage transmission lines and evaluating energy losses caused by corona discharge. The influence of electric field intensity, voltage level, load conditions, and environmental factors on the corona process was examined through theoretical and experimental investigations. The research employed system analysis, mathematical modeling of electromagnetic processes, experimental measurements, and statistical data processing methods. The results revealed the relationship between corona losses and load losses as a function of voltage level and enabled the development of evaluation criteria for selecting the optimal operating voltage of transmission lines. Monitoring results demonstrate the potential for reducing energy losses and improving the operational efficiency of high-voltage power networks. The scientific novelty of the study lies in the proposed integrated approach for real-time monitoring of corona discharge and the evaluation of energy losses through the integration of monitoring data with theoretical models. The obtained results have significant scientific and practical value for the design and operation of electric power systems, improving diagnostic reliability, predicting emergency conditions, and implementing intelligent monitoring and adaptive control systems within digital power networks.
Copyright (c) 2026 Tovbayev, A.N., Tog'ayev, L.B. (Muallif) https://creativecommons.org/licenses/by/4.0
CHARACTERIZATION OF CALCIUM-RICH STEEL SLAG WITH FLUORINE-BEARING MICRODOMAINS
In this study, steel slag particles were examined by scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS) to clarify how micro-scale morphology relates to local chemical composition. High-magnification secondary-electron images showed that the slag consists predominantly of angular, brittle fragments with sharp edges and irregular particle outlines, which is typical of rapid fracture of heterogeneous, hard phases. Many surfaces exhibited lamellar, stepped, or cleavage-like features, indicating preferential crack propagation along phase boundaries or crystallographic planes. In addition, numerous fine particles were observed adhering to larger fragments and accumulating in surface recesses, suggesting either mechanical attrition during handling/grinding or the presence of weakly bonded secondary phases. The coexistence of smooth, plate-like regions and more granular, porous zones supports the interpretation of a multi-phase material with localized differences in toughness and fracture mechanisms. Elemental characterization was performed using an EDS map-sum spectrum collected from a representative area of the particle surface. The spectrum was dominated by calcium, evidenced by a strong Ca Kα peak, accompanied by oxygen as the second major component, consistent with a matrix rich in Ca-bearing oxides and/or silicates. A noticeable fluorine contribution was also detected, implying the presence of fluoride-containing phases or residual flux-related compounds intro-duced during steelmaking and slag conditioning. Silicon and magnesium appeared as minor constituents, which may reflect limited amounts of silicate phases and Mg-bearing oxides/spinels dispersed within the Ca-rich matrix. Manganese was detected only at trace level, suggesting either dilute substitution in oxide phases or small inclusions below the spatial resolution of the map-sum area.
Copyright (c) 2026 Mardonov, B.T., Sayfidinova, M.X. (Muallif) https://creativecommons.org/licenses/by/4.0
DEVELOPMENT AND STUDY OF A SIMULATION MODEL OF A MILLING MACHINE POSITIONING SYSTEM
Maqolada NF-630 frezalash dastgohining (vertikal-frezalash, CNC bilan jihozlangan yoki NF-630M kabi modifikatsiyalarda) imitatsion modeli ko’rib chiqiladi. Model MATLAB/Simulink dasturida qurilgan bo’lib, X va Y o’qlari pozitsiyalash va konturli ishlov berishda, ya’ni ikkala o’q bir vaqtda harakatlanganda, qanday xatti-harakatlanishini tushunish uchun mo’ljallangan. Asosiy e’tibor elektromexanik haydovchilar (drayvlar)ga qaratilgan, ularda rotorlar va stollar inersiyasi, vintli juftliklar yoki tasmalardagi elastiklik, shuningdek, yopishqoq va quruq ishqalanish va tok, moment, tezliklar hisobga olingan. Model klassik kaskadli tuzilmani amalga oshiradi: ichki tok halqasi, tezlik halqasi va tashqi joylashuv halqasi. Barcha halqalar PID boshqaruvchilardan foydalanadi, ammo tezlik va tezlanish uchun "feedforward" va o’qlar orasidagi vaqt mos kelmasligi va kontur xatosini (trayektoriya aylananing o’rniga ellips yoki "do’nglik" shaklida paydo bo’lishi) kamaytirish uchun oddiy koordinatsiya usullari qo’shilgan. Model turli rejimlarni simulyatsiya qilish imkonini beradi: silliq tezlanish/ sekinlashish, keskin yuk o’zgarishi, turli tezliklar-da aylana interpolatsiyasi, chiziqli o’tish va hatto ba’zi 3D trayektoriyalar. Parametrik tahlil batafsil o’rganilgan: turli boshqaruv halqalarida Kp, Ki, Kd qiymatlarini o’zgartirish, tarmoqli kengligining ta’siri, ishqalanishni kompensatsiya qilish va joylashuv bikrligini pasaytirishni o’rganish. Bu, ayniqsa, samarali feedforward ni joriy etish va joylashuv halqasida proportsional kuchaytirishni haddan tashqari oshirmaslik orqali koeffitsientlarni to’g’ri sozlash imkonini berdi. Natijada, dinamik xatolar sezilarli darajada (hisob-kitoblarga ko’ra 40% dan 60% gacha, trayektoriya va tezlikka qarab) kamaydi. Elastik ulanishlardan kelib chiqqan tebranishlar deyarli yo’qol-di, harakat ancha silliqlashdi va o’rnatish vaqti o’zgarmadi.
Copyright (c) 2026 Egamberdiyev, I.P., Ochilov, U.Y. (Muallif) https://creativecommons.org/licenses/by/4.0
EFFECT OF CUTTING SPEED ON THE ACCURACY AND SURFACE ROUGHNESS OF CYLINDRICAL GEARS DURING SHAVING
The relationship between the accuracy and surface roughness of the tooth flanks of cylindrical gears and the cutting speed during finishing with a shaving–rolling tool (shaver–roller) was investigated and described mathematically. The goal was to identify patterns governing the formation of flank micro-geometry under different cutting conditions and to develop a predictive model that estimates quality indicators without requiring labor-intensive production-scale trials. The experimental study was conducted on a Vturn-46 CNC lathe using a special two-axis fixture that ensures stable positioning and coordinated relative motion between the tool and the workpiece. The workpieces were spur gears made of 40Kh steel (GOST 4543-71) with parameters m = 3 and z = 24. Initial geometry was generated by gear hobbing, followed by finishing through shaving–rolling. Tests were performed at various cutting speeds, with each regime tested on batches of 10 workpieces to assess reproducibility and reduce the effects of random factors. Surface quality was evaluated based on the accuracy and roughness of the tooth flanks, as well as the microprofile changes relative to cutting speed and feed parameters. The developed mathematical model accurately captures how cutting speed and feed conditions influence micro-geometry formation and shows good agreement with experimental data. It demonstrates that changes in cutting speed cause systematic shifts in contact interaction conditions and plastic deformation behavior in the processing zone, which directly affect roughness levels and the stability of tooth profile formation. The model can be used to select optimal finishing parameters and plan processes more efficiently, reducing the need for extensive full-scale experiments. The results confirm that shaving–rolling can be effectively performed on gen-eral-purpose CNC equipment as an alternative to specialized gear-finishing machines. This method improves accuracy and lowers the surface roughness of the tooth flanks, broadening opportunities for finishing operations in small-batch and repair production environments.. Keywords: cylindrical gears; shaver-roller; cutting speed; precision; roughness; finishing; CNC; 40X steel
Copyright (c) 2026 Mardonov, B.T., Shakulov, B.K., Sayfidinov, O.O. (Muallif) https://creativecommons.org/licenses/by/4.0
CURRENT STATUS AND FUTURE PROSPECTS OF COAL MINING IN PAKISTAN
The coal mining sector in Pakistan is a key contributor towards the socio-economic uplift of the mineral sector, as well as the country's energy needs and social security. Data scarcity related to the mining accidents results in recurring fatalities and injuries, costing lives, money, and time, making the ongoing coal mining operations more risky, expensive, and complex. Research regarding the underlying factors culminating in accidents is indispensable to understanding the subject matter well and overcoming it by devising effective strategies accordingly. Hence, without the provision of relevant data, it becomes impossible to investigate the underlying dynamics, consequences, and remedial measures of mine accidents. Furthermore, the lack of will to adopt technology further adds to the problems of the mining industry. This study aims to present different aspects that directly and indirectly affect the safety of the underground coal mining industry in Pakistan, namely data scarcity, lack of research, and application of technology. In addition, this study presents the predicted situation of the mining sector in the next 30 years in Pakistan based on the exponential triple smoothing method analysis. Moreover, effective strategies are also proposed to overcome potential safety problems in Pakistan's coal mining industry.
safety issues in Pakistan’s mining industry
Copyright (c) 2026 Batool, A., Kumar, S., Shahani, N.M. (Muallif) https://creativecommons.org/licenses/by/4.0
OPPORTUNITIES FOR IMPROVING THE EFFICIENCY OF INTAKE AIR CLEANING IN INTERNAL COMBUSTION ENGINES OF MINING MACHINERY
Under open-pit mining conditions, internal combustion engines operate in environments with a high concentration of abrasive dust, which leads to intensive wear of the cylinder–piston group, power reduction, increased fuel consumption, and a decrease in engine service life. This paper presents a comprehensive analysis of the influence of the particle size distribution and concentration of dust in the intake air on the tribological condition of key engine components, the parame-ters of the oil film, and the operational performance of the power unit. It is shown that particles with sizes of 5–20 μm pose the greatest risk, causing accelerated abrasive wear and deterioration of combustion chamber sealing. Based on theoretical considerations and operational data, the necessity of improving the efficiency of intake air purification is substantiated. A design of a multi-stage combined air filtration system is developed and proposed, including multicyclone pre-cleaning, two-stage electrostatic separation, and final purification using a conventional filter element. The proposed system ensures effective capture of particles within a wide size range (0.1–20 μm) under low aero-dynamic resistance and increases the overall filtration efficiency up to 95%. The implementation of the developed system makes it possible to reduce the wear rate of the cylinder–piston group, extend the service life of both the base filter and the engine as a whole, decrease specific fuel consumption, and improve the operational reliability of mining machines under high-dust conditions.
Copyright (c) 2026 Djuraev, R.U., Kayumov, U.E. (Muallif) https://creativecommons.org/licenses/by/4.0
JUSTIFICATION OF OPTIONS FOR THE SYSTEM OF OPENING UP CONTOUR RESERVES IN OPEN-PIT AND UNDERGROUND DEVELOPMENT OF ORE DEPOSITS IN MOUNTAIN AREAS
The paper addresses the issues of improving the efficiency of ore deposit development in mountainous regions by substantiating options for accessing contour reserves under open–underground mining conditions. The relevance of the study is driven by the need to involve reserves located beyond the open-pit con-tour in mining under increasingly complex mining and geological as well as mining and technical conditions. Particular attention is paid to analyzing the feasibility of using the open-pit area as the main access element for the development of contour and off-contour reserves. It is shown that the use of the pit space for locating access workings and ore transportation makes it possible to reduce the volume of capital mine workings, shorten the time required to bring reserves into operation, and improve the economic efficiency of combined mining. The study provides a comparative analysis of possible technological access schemes depending on the spatial position of reserves relative to pit elements, their depth of occurrence, and the adopted transportation system. Various options for accessing contour and off-contour reserves using shafts, inclined and horizontal workings, as well as the open-pit area, are developed and systematized. For each option, areas of rational application are identified with due regard to mining and geological conditions, pit parameters, and safety requirements. The obtained results can be applied in the design and optimization of access systems for ore deposits developed by open–underground mining methods in mountainous regions.
Copyright (c) 2026 Misliboev, I.T., Mutavaliev, A.T., Tadjiyev, Sh.T. (Muallif) https://creativecommons.org/licenses/by/4.0
THE EFFECT OF HYDROGEN SULFIDE ON THE IN-SITU LEACHING OF URANIUM FROM CARBONATE–SULFIDE-BEARING ORES
This study investigates the influence of hydrogen sulfide (H₂S) on the in-situ uranium leaching process, with particular emphasis on its role in the reduction of hexavalent uranium to the tetravalent state, as well as the associated technological disruptions and severe equipment corrosion. The objective of the research was to determine the causes of H₂S formation, assess its impact on process stability, and develop effective neutralization methods. The research methodology included sampling of rock materials and productive solutions from production wells at the GTK-2 uranium deposit. Rock-forming and ore minerals were examined using scanning electron microscopy (SEM) and a Nikon ECLIPSE LV100N POL microscope at magnifications ranging from 40× to 1000×. In addition, the causes of hydrogen sulfide formation in the ore environment were investigated. The results showed that the H₂S concentration reached up to 320 mg/L in several production wells, whereas no hydrogen sulfide was detected in others. Productive solutions with elevated H₂S concentrations were analyzed at the Central Physicochemical Laboratory of the Zafarabad Mining Administration. Hydrogen peroxide (H₂O₂) was used to neutralize hydrogen sulfide, achieving a reaction efficiency of approximately 60%, with water and sulfuric acid as the reaction products. The scientific novelty of the study lies in the comprehensive analysis of the reducing effect of H₂S on uranium and the substantiation of hydrogen peroxide application for stabilizing the in-situ leaching process. The obtained results have significant practical importance for reducing corrosion damage, improving process reliability, and minimizing economic losses at uranium mining enterprises.
Copyright (c) 2026 Aliqulov, Sh.Sh., Navruzov, T.Y., Xalimov, I.U., Sharopov, Q.R (Muallif) https://creativecommons.org/licenses/by/4.0
NON-CONVENTIONAL HYDROMETALLURGICAL SEPARATION OF IRON, ZINC, AND COPPER FROM COPPER INDUSTRY WASTE
In this study, the possibilities of efficiently separating iron, zinc, and copper from copper smelting slag, which is a waste of the copper industry, using a non-conventional hydrometallurgical method were investigated. The recycling of such wastes is important not only for the recovery of valuable metals but also for reducing their negative impact on the environment. In order to eliminate technological problems that arise during the filtration stage after sulfuric acid leaching of copper smelting slag, the research was carried out in three stages. First, the slag sample was selectively leached with sulfuric acid; in the second stage, the obtained solution was dried; and in the final stage, the resulting solid metal sulfates were selectively leached with water. During the sulfuric acid leaching process, the effects of acid concentration, leaching time, temperature, and stirring speed on the transfer of metals into the solution were comprehensively investigated. The experimental results showed that an acid concentration of 2 M, a leaching time of 120 minutes, a temperature of 90 °C, and a stirring speed of 300 rpm are optimal conditions for metal dissolution. Under these conditions, the degree of metal dissolution into the solution was 89.5% for Cu, 88.7% for Zn, and 59.2% for Fe. The solution obtained after selective leaching was dried at 150 °C for 90 minutes to obtain solid metal sulfates. In the next stage, this product was selectively leached with water, and it was determined that a leaching time of 40 minutes and a temperature of 40 °C are the most favorable conditions for the transfer of metals into the solution.
Copyright (c) 2026 Axmedov, M.S., Yuldoshev, S.M., Azimova, A.B. (Muallif) https://creativecommons.org/licenses/by/4.0
KINETICS AND INFLUENCING FACTORS IN THE CARBOTHERMIC REDUCTION PROCESS OF STEELMAKING DUST
The present paper sets out the findings of a scientific investigation into the kinetics and key influencing factors of the carbothermic reduction process of steelmaking dust. Electric arc furnace dust has been found to contain significant quantities of iron and zinc oxides, which represent valuable secondary raw materials, but which also pose serious environmental risks. The present study focuses on the effects of temperature and content, particle size, gas atmosphere, and reduction time on the reduction kinetics. Carbothermic reduction experiments were conducted within the temperature range of 700–1150°C, with coke serving as the reducing agent. The degree of reduction and metallization was determined through gravimetric and phase analysis. Phase composition and microstructural changes were examined using X-ray diffraction, scanning electron microscopy, and energy-dispersive spectroscopy. The experimental data were analysed using the shrinking core model to identify the rate-controlling steps of the process. The findings suggest that zinc oxide undergoes reduction more rapidly than iron oxides, a phenomenon attributable to its diminished thermodynamic stability and volatilization behaviour. The activation energies and kinetic parameters were calculated based on the Arrhenius equation. The findings provide a scientific basis for the optimisation of carbothermic reduction processes and the improvement of the efficiency of steelmaking dust recycling under industrially relevant conditions.
Copyright (c) 2026 Ilхamov, M.A., Munosibov, Sh.M., Matkarimov, S.T., Karimjonov, B.R. (Muallif) https://creativecommons.org/licenses/by/4.0
INDUSTRIAL APPLICATION OF SODIUM LIGNOSULFONATE IN THE PROCESSING OF CARBONACEOUS GOLD-BEARING CONCENTRATES
At present, the global gold mining industry is facing objective technological challenges caused by the depletion of reserves of easily beneficiated oxidized gold-bearing ores and the increasing proportion of refractory mineral raw materials. Significant processing difficulties arise from the structural and mineralogical heterogeneity of gold, its occurrence in ultrafine and nanoscale forms (1 nm = 10⁻⁹ m), as well as the close association of gold particles with sulfide mineral matrices and carbonaceous components of ores. The presence of naturally occurring active carbon leads to the so-called “preg-robbing” effect, which reduces gold recovery during conventional cyanidation. These factors necessitate the involvement of double- and triple-refractory ores in processing and the development of specialized, scientifically grounded technological solutions.
Copyright (c) 2026 Sanakulov, K., Ergashev, U.A., Karomatov, S.S., Chuliyev, G.F., Farmonov, I.Z. (Muallif) https://creativecommons.org/licenses/by/4.0