The objective of this work is to study the material composition of refractory gold-bearing ore, based on the results of which possible methods will be assessed and recommendations will be given for selecting the necessary process solutions. The object of research in this work was a process sample of carbonaceous gold-bearing ore of the Amantaytau deposit (Central Kyzylkum, Uzbekistan). Chemical, granulometric and phase analyzes, as well as a mineralogical study using modern optical and electronic methods were carried out. Phase analysis established that a significant part (56.12 %) of gold is in a refractory form associated with sulfide minerals and carbonaceous components. The revealed textural and structural features and distribution of gold confirm the complex nature of the ore and the need to use combined process flowsheets. The results of laboratory tests showed low efficiency of the gravity method, which is due to the fine dissemination of gold. For further processing, the expediency of using fine grinding, flotation enrichment with subsequent pyrometallurgical or hydrometallurgical processing of concentrates is substantiated. 

This article examines the force factors acting on particles within a rotary mill of proprietary design. The industrial prototype was developed based on the principle of complex dynamic loading of the feed material (including impact combined with abrasion, shear, and other mechanisms), enabling fine and ultra-fine grinding of diverse materials, as well as pneumatic homogenization and mechanical activation. The study seeks to broaden current mathematical models describing two-phase flow dynamics in rotary mills by providing a differentiated numerical analysis of how each force component influences grinding efficiency. It addresses the challenges of modeling grinding processes, proposes simulation approaches for two-phase flows in rotary mills, and presents a refined aerodynamic force model that accounts for particle shape and physical-mechanical properties. Through numerical and simulation-based modeling, the motion behavior of particles with diameters ranging from davg = 10–50 μm was investigated. The findings inform design improvements to the mill’s grinding chamber by enhancing particle collision rates, modifying aerodynamics, and intensifying the overall grinding process. The force values derived from numerical simulations can contribute to the further development of rotary mill designs and grinding technologies for a wide range of materials. The results demonstrate that a comprehensive understanding of particle dynamics within the grinding chamber enables the creation of more effective process models — especially under conditions where grinding kinetics and particle motion can be considered independently.The study was carried out under the grant issued by the Russian Science Foundation No. 23-19-00796 (https://rscf.ru/project/23-19-00796/) using the equipment of the Center for High Technologies based on of the Belgorod State Technological University named after V. G. Shukhov.

This study examines the bacterial-chemical leaching process for extracting nickel, copper, and cobalt from sulfide ore of the Shanuch deposit (Kamchatka), utilizing ultrasonic radiation to enhance the leaching efficiency. For the experiment, ultrasonic vibrations were applied at an intensity of 21.0 W/cm2 and a frequency of 22 kHz, with a total generator power of 400 W. The ultrasonic treatment was conducted for 30 minutes in a flow chamber setup. The results showed significant improvements in metal recovery during bacterialchemical leaching with ultrasonic treatment, achieving 79.42 % recovery for nickel and 72.55 % recovery for cobalt. In contrast, the leaching process without ultrasound resulted in much lower extraction rates — 2.65 times lower for nickel and 2.49 times lower for cobalt. However, the copper extraction remained relatively low at 24.07 %, though ultrasonic treatment enhanced copper extraction by 1.58 times compared to the non-ultrasonic process. Experiments also demonstrated that bacterial-chemical leaching, with an ore pulp solid-to-liquid ratio of 1 : 5 and a bacterial suspension solid-to-liquid ratio of 1 : 7, resulted in polymetallic solutions containing up to 3.59 g/L of nickel, 0.171 g/L of copper, and 0.0984 g/L of cobalt. To further optimize metal recovery, continued research should focus on varying ore pulp and bacterial suspension densities in bacterialchemical leaching, as well as adjusting ultrasonic exposure duration, frequency, and intensity.

This paper discusses the development of an intelligent control system (ICS) designed to optimize the biotechnological processing of gold-bearing sulfide concentrates. The focus is on the fuzzy control of key process parameters such as temperature, slurry pH, and the air flow rate supplied under pressure to the bioreactor module. These parameters are critical for maintaining the appropriate concentration of ferrous iron ions in the slurry, which directly influences the efficiency of the bacterial oxidation (BO) process. The system operates based on real-time sensor data, allowing it to promptly respond to variations and maintain optimal bioreactor conditions. The proposed control system is a sophisticated hierarchical hardware and software structure, incorporating software modules designed for fuzzy control. A rule base for the fuzzy controllers was developed, and a simulation model of the control system was created using the Fuzzy Logic Toolbox in MATLAB. This model not only predicts the system’s behavior under various conditions but also optimizes control parameters to maximize BO efficiency. By employing fuzzy logic for process parameter monitoring and control, the system enhances adaptability to input parameter variations and reduces the impact of external disturbances. Simulation results for temperature control in the bioreactor show a 2.1 % improvement in accuracy with the fuzzy logic con trolsystem, compared to the traditional PID controller. Additionally, the system results in reduced consumption of reagents, such as sulfuric acid and cyanide.

Crushed stone is widely used as a versatile aggregate in construction. The growing demand for high-quality aggregates underscores the importance of assessing the strength properties of both the rock and the crushed product during exploration and subsurface studies. Understanding how processing affects these properties is crucial for optimizing crushed aggregate production. This study aims to investigate the shape characteristics of crushed stone particles and evaluate their influence on the physical and mechanical properties of the final  product. The findings indicate that different stages of gabbrodolerite processing significantly impact its properties. Specific particle shapes were found to improve the strength characteristics of the crushed stone, providing new insights into the effects of crushing processes. An improvement in the quality characteristics of gabbrodolerite after primary crushing with a JC 1600 crusher was observed when compared to the original samples (post-explosive fracturing). The key particle shape characteristic, the flakiness index, was reduced by 2 to 2.5 times after the third stage of processing with the HP4 A and Barmac B9100SE crushers. Crushed stone subjected to three stages of crushing exhibited improved strength, as evidenced by reduced mass loss when establishing crushability decreased of 1.5 to 2 times, losses by micro-Deval decreased on the average by 2.4 %. Simulations of particle wear demonstrated changes in shape, with an increase in roundness and a reduction in surface roughness and flatness, while elongation remained nearly unchanged. A study of the physical and mechanical properties and shape characteristics of crushed stone has revealed certain patterns that indicate which types of stone are best suited for different construction tasks. The research was funded by the federal budget to fulfill the state assignment for the Institute of Geology of the Karelian Research Center of the Russian Academy of Sciences.

This article commemorates Sergey Efimovich Andreev, a distinguished scientist and pioneer in industrial management, who served as a professor at the Leningrad Mining Institute and was honored for his contributions to science and technology. During the 1920s and 1930s, he played a pivotal role in establishing and advancing the mineral processing industry in the USSR. Throughout his career, S. E. Andreev dedicated himself to mining science, technology and education, shaping the minds of hundreds of highly qualified mining engineers at the Leningrad Mining Institute. His scientific legacy remains influential today, particularly for his theoretical advancements in mineral processing. Notably, S. E. Andreev’s contributions extended beyond academia as he successfully bridged scientific theory with practical industrial applications. From 1922 to 1930, he co-founded and led the pioneering Russian research institute of Mekhanobr alongside esteemed professor G. O. Chechott, focusing on mineral processing research and training of researchers and industry specialists. Despite his profound impact, Professor Sergei Efimovich Andreev’s biography has surprisingly not been thoroughly explored in historical research until now. This publication seeks to rectify this oversight, ensuring that his significant contributions to both science and industry receive their rightful recognition.

Plant performance reports contain calculated data for processing plant indicators that cannot be directly measured and are widely used in industrial environments. This article discusses two available calculation options: compilation of a system of balance equations based on the relevant product testing data, and development of a mass balance equation based on the relevant weighing results. The quality of any plant performance data depends on the errors in establishing the known quantities included in the equations. In the first option, these include sampling errors for the ore, concentrate, and tailings, as well as ore amenability errors; in the second option, these are weighing errors for the ore and concentrates, as well as errors in establishing the masses of products in containers included in the performance data calculation scope. The most suitable performance data calculation option is selected depending on the magnitude and ratio of these errors specific to a particular processing plant. The two options are equivalent for a plant with high ore amenability and a simple system of balance equations (two to three equations) without a thickener in the calculation scope. For plants with low amenability and a more complex system of equations, the second option (a mass balance of the weighed products) is preferable. Only the second option should be used for plants with ore amenability indices of less than 2; with or without dry concentrate mass weighing in a thickener (for dry processes), it is advisable to use the second option at all plants. The relative random error formulas for the plant performance data calculation options allow selecting the applicable option for other situations beyond those discussed in the article.The study was supported by the Ministry of Science and Higher Education of the Russian Federation (No. 0833-2023-0004) under the state assignment for the Ural State Mining University.

The chrysotile industry in the Russian Federation has managed to adapt to modern challenges, minimize its production risks, convert from single product manufacture to producing a diversified range of products, and successfully reorient its sales markets. This article discusses resource conservation and integrated development of natural mineral reserves using the example of gabbro-diabase rock processing. At the Bazhenov chrysotile deposit developed by Uralasbest PJSC, this approach led to a reduction in the environmental load and lower dumping and reclamation costs. Melting gabbro-diabase from the Bazhenov deposit enables the industry to manufacture a new product: mineral wool, an effective fireproof heat and sound insulating material for the construction industry. The proven technology for manufacturing mineral wool thermal insulation boards has been identified as the most cost-effective. The thermal insulation materials plant of Uralasbest PJSC uses mineral wool boards to produce unique hydroponic substrate, which is widely used in agriculture for growing vegetables, fruits, legumes, ornamental and flower crops. Its high water retention capacity is achieved by including a mixture of polyethylene glycol, a moisture-retaining component, into the composition of the mineral wool instead of a hydrophobic oil emulsion. An integrated approach to utilizing mineral resources has also been successfully implemented at another production facility of Uralasbest PJSC, for manufacturing fractionated crushed stone for road construction. The company’s many years of experience have demonstrated that increasingly integrated processing of natural mineral raw materials provides undeniable new opportunities for the enterprise to generate additional profit by introducing new types of products.

Laboratory studies have been completed to identify proper processing methods for the ore of the Altyn-Zhylga deposit in Kyrgyzstan. In terms of its main components, the ore rates as sulfide gold- and silver-bearing ore, with copper as the associated valuable component. Valuable minerals are intergrown with the host rock in fine interpenetrations, contributing to refractory qualities of the ore. The average gold content in the ore sample was 5.29 g/t, with 23.15 g/t of silver. Given the high losses of valuable components with gravity and flotation tailings, the recommended ore treatment methods for gold recovery were based on combinations of flotation and cyanidation, gravity concentration (table concentration, centrifugal concentration) and cyanidation. Cyanidation of flotation tailings rendered processing waste (cyanidation cakes) with a lower gold content of 0.2 g/t, which in turn improved the total Au recovery. Gold loss with the cyanidation cakes totaled 3.0 %. The tests demonstrated total gold recoveries of 83.5–86.7 % for the flotation + cyanidation technology and of 88.7–90.1 % for the gravity concentration + cyanidation technology. A rational analysis was carried out to identify the mineral form enabling gold and silver losses in flotation tailings. The analysis has shown that non-recoverable gold is distributed evenly among the mineral components and has a subtle and close connection with them. The complete chemical analysis data clearly demonstrate that the contents of valuable components (copper, gold, and silver) in the resulting gravity and flotation concentrates meet the applicable requirements and that these concentrates may be sent to non-ferrous metallurgy plants for processing.

This article presents the results of technological laboratory studies aimed at assessing the feasibility of using gravity concentration methods to isolate nepheline concentrate from apatite flotation tailings obtained in the processing of ores from the Khibiny deposits. The material composition features identified for a sample of this material and the final processing products suggests that gravity concentration of the initial feed is facilitated by separating titanite particles, pyroxenes, and amphiboles into the heavy fraction and nepheline into the light fraction. Effective gravity concentration of the initial feed is hindered by the small difference in densities between the valuable mineral and the waste rock, as well as by the presence of feldspars and a number of other rock-forming minerals in the feed, with densities comparable to or lower than the density of nepheline. A series of technological experiments have confirmed the fundamental feasibility of using the processing methods considered to obtain nepheline concentrate. It has been established that it is difficult to obtain a high-grade concentrate from the feed using gravity concentration methods exclusively. Various gravity concentration options, based on spiral separation, have been proposed for obtaining crude nepheline concentrate from apatite flotation tailings. These produce a concentrate with a mass fraction of Al2O3 of 25.2–25.8 % and a total recovery of 75.8–77.9 %. The standard grade for this concentrate may then be ensured through final treatment by flotation methods. Implementation of the proposed process solutions using resourcesaving gravity concentrate methods will improve nepheline flotation feed grades while simultaneously reducing the flotation time. This will contribute to stable yields of high-grade nepheline concentrates from low-grade refractory mineral raw materials of variable compositions.