Backfilling technology is not always used by mining enterprises, which is conditioned by technological and economic factors, such as the need for high mining rates and costs for the technological processes of transporting backfill materials from the daylight surface to the mined-out space. This concerns the underground mining of hard coal, which is a strategic energy resource, in the mines of Ukraine. This paper aims to study the effect of leaving the waste bottom rocks in the mined-out space of the longwall face without their drawing to the earth’s surface on the geomechanical state of the rocks surrounding the longwall face. The geomechanical assessment of the stress state of the rock mass surrounding the longwall face, when leaving the waste rocks from the seam bottom rocks in the mined-out space, is performed by the finite element method using the Ansys software package. A geomechanical model has been developed and substantiated, which adequately reflects the mining-geological conditions for seam mining within the extraction site, the actual structure and properties of the coal-bearing rock stratum, the parameters of the longwall face and the modified powered support for the processes of leaving the rocks in the mined-out space. The values and patterns have been determined of the decrease in the stress intensity concentrations in the coal-bearing roof mass in the frontal bearing pressure zone and destressing zone with an increase in the ratio of the rock pack thickness to the extracting seam thickness. The relative indicators of the load on the powered support section and the lowering of its roof have been determined by the ratio of the thickness of the rock pack formed in the mined-out space to the extracting seam thickness. The proposed mining method is of significant commercial and research interest for owners of coal mines developing thin coal seams because environmental costs for placing waste on the surface are reduced, and the energy potential of coal is increased due to the separation of waste rocks from coal in underground conditions. The need for a cycle of beneficiation of mined mass is eliminated and the geomechanical conditions of coal mining processes are improved. © 2022 by the authors.

The study investigates the concentration of chemical elements in biological tissues (placenta and blood) of women from the Akmola region, Kazakhstan to assess the impact of environmental pollution on maternal and newborn health. The research conducted from 2018 to 2021 involved 67 placental and umbilical cord blood samples collected from women in four Akmola districts. The study utilized instrumental neutron activation analysis and electronic microscopy to determine the concentration of 28 chemical elements. Statistical methods were applied to analyze the distribution, including the mean values, standard deviations, and frequency distribution curves. Significant variability in chemical element concentrations was observed across samples, with notable differences in rare earth elements and heavy metals. Elements such as sodium (Na), calcium (Ca), and chromium (Cr) displayed high variation. The study identified a strong environmental influence on the accumulation of toxic elements in the placenta and blood. The accumulation of chemical elements in biological tissues was heterogeneous, influenced by natural and anthropogenic factors. Blood was found to be more sensitive to environmental contamination compared to the placenta, indicating the need for enhanced environmental health monitoring in the region. © 2025 The authors.

Corporate social responsibility affects the financial efficiency of the company, but this influence is most significant under certain environmental conditions, demonstrating a tendency to improve the situation in macroeconomics. However, the very mechanism of such influence remains unexplored. For the practical application of corporate social responsibility for the company’s benefit, it is important to connect corporate social responsibility indicators, environmental parameters with financial metrics. The research purpose is to justify the concept of adaptive management of corporate social responsibility for quasi-public sector companies in the context of macroeconomics changing factors. Research methodology: general scientific methods of cognition: comparison, analysis and synthesis, as well as system-situational, dialectical, abstract-theoretical, structural-functional, and systemic. The study hypothesized that by introducing the impact of the quality of CSR management on the financial performance of a quasi-public sector company, it is possible to provide a high gross domestic product growth rate. The concept of corporate social responsibility management for companies in the quasi-public sector has been developed. It was stated that the largest numerical values of the coefficients for 2018 and 2019 are more than 0.7 units. It was during those years, in accordance with the research results, that low (less than 6 %) inflation and a high GDP growth rate (more than 5 %) took place. Using the concept will make it possible to implement a systematic approach in the management of corporate social responsibility and ensure the conditions for achieving goals in the company of the quasi-public sector © 2022. Authors. This is an open access article under the Creative Commons CC BY license

This study presents a numerical and experimental investigation of the thermal performance of borehole heat exchangers for ground source heat pump systems. A 3D model was developed for heat and mass transfer in soil and grout, coupled with 1D conductive and convective heat transfer through the pipe and circulating fluid. The model was implemented in COMSOL Multiphysics and validated using thermal response test data obtained from two 50 m-deep boreholes drilled in the Almaty region of Kazakhstan. The root-mean-square deviation between model predictions and TRT data was 0.184°C. The thermal conductivity of the soil (λg = 2.35W/mK) and thermal resistance (Rb = 0.20mK/W) were determined. Simulation results showed that spiral borehole heat exchangers provided the highest heat extraction and reduced drilling depth by 34.6% compared to single U-type. The model aids in optimizing borehole heat exchanger geometry and evaluating material properties for enhanced thermal efficiency. © The Author(s), under exclusive licence to Springer Nature Switzerland AG 2025.

The pressing issue of global warming, coupled with the increasing depletion of fossil fuels, highlights the necessity for sustainable energy solutions. In this context, hydrogen stands out as a viable option, possessing the capacity to revolutionize critical industries, including fuel cells, internal combustion engines, and gas turbines. An effective approach to enhancing numerous chemical and technological processes in liquid and steam–gas mixtures is the establishment of cavitation mixing zones for the reacting components. These zones are produced in specialized reactors that operate on the principles of hydrodynamic effects applied to the reaction medium. The study focused on the design of the cavitation-jet chamber utilizing the k– (Formula presented.) Turbulence Model and Particle Tracing Model. As a result, the influence of the inlet velocity on cavitation formation and the uniformity of mixing was investigated. Ripley’s K-function was used to analyze the results of particle distribution. The influence of the screw on flow turbulence and the uniformity of particles was evaluated. Analysis through the K-function indicated a decrease in uniformity at lower velocities, with noticeable turbulization of the flow occurring at high velocities, which facilitated better mixing. In contrast, without the screw, the flow exhibited a high longitudinal velocity and minimal transverse velocity, limiting particle dispersion to the radius of the nozzle and resulting in inefficient mixing. It was found that the inclusion of the screw not only enhanced particle distribution but also maintained the size of the cavitation zones, thereby improving the overall efficiency of the design.

The article discusses the improvement of methods of tracing transport networks in the context of optimal planning of cities and settlements. It is necessary to provide a systematic approach to planning. The development of the master plan considers the division of the territory into traditional functional zones. Functional zones are modeled in the form of circles and rectangles. Then these zones are divided into separate subsets. Objects located inside functional zones are modeled by points, and objects connecting these points by straight lines. Network tracing is achieved by constructing an orthogonal Steiner network taking into account the weight coefficients of the functional zones. Orthogonal or Euclidean Steiner networks are constructed in subsets. The construction of a network and pedestrian roads inside the functional zones is being carried out. When solving this problem, the calculation of the need for transport is also provided. Optimization of the transport network tracing is as follows: for a given set of points, it is required to determine the number and optimal location of additional points, so that the total length of the network is minimal. The shortest path to the points is determined. Optimization geometric models are an effective and visual means of developing various options for tracing the network between functional zones and within zones. From several network tracing options, a network that meets the pre-set planning requirements is selected. Allows you to analyze and make the right decision in determining the promising direction of development and construction of a city or settlement. © 2023 K. A. Kuspekov.

Problems with increasing heavy metal contents in natural waters are becoming a global issue. At the same time, improved methods for water treatment are becoming increasingly important. In this context, natural zeolites can be used to purify polluted water. In this paper, we investigated how the adsorption capacity of natural zeolites can be improved. Natural zeolites from the Shankanay district, Almaty, Kazakhstan, were used as adsorbent material for experiments on improving the water treatment of heavy metals. We found that the adsorption capacity for heavy metals was increased greatly by thermal activation using furnace treatment. The optimal thermal activation condition was about 550 °C for a duration of 2 h. However, the improved adsorption capacity for different heavy metals varied depending on the heat treatment temperature. Adsorption by the heat-treated zeolites at a temperature of 550 °C was 87% for nickel, 99% for copper and cadmium, and 100% for lead. Adsorption by heat-treated zeolites at a temperature of 500 °C was 78% for nickel, 98% for copper, 83% for cadmium, and 88% for lead. The residual concentration of heavy metals in the filtered water did not exceed the maximum permissible concentrations for drinking purposes. In all experiments, intense adsorption took place during the first 10 min representing 35 to 61% of the metal ions in the water. Adsorption properties were verified using adsorption capacity (BET), IR spectroscopy, and scanning electron microscopy. The study shows that modified Shankanay natural zeolites have great potential as a low-cost adsorbent material for purifying water from heavy metals. © 2023 by the authors.

The paper contains the laboratory study results for the flotation processing of gold-containing tailings with the use of the composite reagent (CF). The CF flotation reagent is a microemulsion from a composition of sodium butyl xanthate and reaflot. A gold-containing concentrate was obtained with a gold content of 6,7 g/t with a recovery of 59,71 % in the basic mode. The use of the CF composite flotation reagent increases the gold extraction into the gold-containing concentrate by 3,77 %, as compared with the main collector-sodium butyl xanthate. The con-sumption of CF flotation reagent is reduced by 20 %. © 2022, Faculty of Metallurgy. All rights reserved.

Anthropogenic CO2 emissions are a major driver of climate change, highlighting the urgent need for effective mitigation strategies. Carbon Capture, Utilization, and Storage (CCUS) offers a promising approach, particularly through CO2-enhanced gas recovery (EGR) in shale reservoirs, which enables simultaneous hydrocarbon production and CO2 sequestration. This study employs a numerical simulation model to compare two injection strategies: CO2 flooding and huff-and-puff (H&P). The results indicate that, without accounting for key mechanisms such as adsorption and molecular diffusion, CO2 H&P provides minimal improvement in methane recovery. When adsorption is included, methane recovery increases by 9%, with 14% of the injected CO2 stored over 40 years. Incorporating diffusion enhances recovery by 19%, although with limited storage potential. In contrast, CO2 flooding improves methane production by 26% and retains up to 94% of the injected CO2. Higher storage efficiency is observed in reservoirs with high porosity and low permeability, particularly in nano-scale pore systems. Overall, CO2 H&P may be a viable EGR option when adsorption and diffusion are considered, while CO2 flooding demonstrates greater effectiveness for both enhanced gas recovery and long-term CO2 storage in shale formations. © 2025 by the authors.

The bottom sediment of reservoirs has many functions. Among them, matter sorption is a very important one, and results in many side-effects on the reservoir sediment forming the water–bottom sediment system. As a result, bottom sediment can also be an indicator of anthropogenic water pollution. There is only very little knowledge of this situation in the study area. The main objective was the analysis of heavy metal accumulation in bottom sediment, as well as their ability to migrate throughout the water–bottom sediment system and their spatial distribution in the Kapshagay Reservoir in Kazakhstan. Heavy metal concentrations, in the both water samples and the bottom sediment, were determined using the atomic absorption spectrophotometric method. Surfer software was used to visualize the processes of migration and accumulation. Another objective was the development of model maps of the spatial distribution of metals in the reservoir water area, which indicated significant anthropogenic loads. It is obvious that both the transboundary inflow of the Ili River and the inflow from small rivers in the territory of Kazakhstan are the reasons for the anthropogenic water and sediment load. The results of the spectrometric analysis verify the water pollution in the reservoir, revealing increased concentrations of zinc reaching up to 10.8 µg/L and lead up to 32.7 µg/L, transported by the transboundary runoff of the Ili River and by the small rivers on the left bank into the Kapshagay Reservoir. Sediment concentrations close to the central part and dam zone of the reservoir reached the following values: zinc up to 37.0 mg/kg and lead up to 8.8 mg/kg. The results of this study indicate a significant anthropogenic load of the ecological conditions of the Kapshagay Reservoir. This is discussed and compared with other relevant studies. © 2022 by the authors.