Engineering Journal of Satbayev University

Geospatial Model for Land Degradation Assessment in the Caspian region based on Integrated Multifactor Indicators

2026-01-19T18:03:35+00:00

Land degradation and desertification are major environmental challenges in the arid Caspian region (Pri-Caspian) of Kazakhstan. This study assesses desertification susceptibility in the Mangystau region using an integrated GIS and remote sensing approach. Four controlling factors were analyzed: distance to active tectonic faults, terrain slope, vegetation cover derived from the Normalized Difference Vegetation Index (NDVI), and soil moisture conditions represented by the Water Requirement Index (WRI). Euclidean distance analysis was used to evaluate tectonic influence, slope gradients were derived from SRTM data, and NDVI and WRI were calculated from Landsat 8 OLI imagery. All factors were reclassified into standardized ordinal classes and integrated using a weighted sum multi-criteria evaluation model to generate a composite desertification susceptibility map. The results indicate strong spatial heterogeneity in degradation conditions. Areas near tectonic faults with steeper slopes, low NDVI, and low WRI values show the highest susceptibility to desertification, while regions with gentle slopes, higher vegetation cover, and better soil moisture exhibit greater environmental stability. The study demonstrates that land degradation in Mangystau is controlled by the combined effects of geological, geomorphological, and ecological factors. The proposed integrated framework provides a reliable tool for desertification assessment and supports sustainable land management in arid and semi-arid environments.

Meta-analysis and systematic review of drone technology in mining and geotechnical engineering

2026-04-29T14:32:22+00:00

Unmanned Aerial Vehicles (UAVs) have revolutionized geotechnical and mining operations by enabling fast, high-resolution, and inexpensive spatial data acquisition, terrain modeling, and monitoring. The current review and meta-analysis integrate observations from over 133 peer-reviewed articles to present a comparison of the accuracy of UAV-based surveying methods, i.e., photogrammetry and LiDAR, and traditional methods such as total stations and terrestrial LiDAR. This study focuses on application of UAVs and drone use in mining and geotechnical engineering in terms of finding stockpile volumes, mining subsidence, mine tailings and dump site, and rock mass identification. UAVs are capable of achieving decent accuracy on a regular basis, as indicated by meta-analysis, if optimized flight parameters, RTK/PPK positioning, and GCPs are utilized. Improved accuracy in UAV LiDAR surveys and balance between visual accuracy and cost-recovery in UAV photogrammetry are feasible. However, error magnitude is dependent on complexity of terrain, flight planning, and meteorology, emphasizing methodical accuracy. Bibliometric analysis indicates exponential publication development per year since 2017 for UAVs, and China once more emerges as the leading contributor with funding, authorship, and research. Keyword and co-authorship network visualization demonstrates increasing adherence to machine learning, 3D reconstruction, and digital twin technologies. SWOT analysis determines UAVs' efficiency of operations, safety benefit, and visual outcome as its major strengths but bottlenecks to data processing, inconsistent accuracy, and difficulties in unfavorable terrain conditions as its weaknesses. Shortages of skills are listed as major weaknesses to extensive deployment. The findings are reinforced by an industry validation survey in which 100% of respondents testified to UAV-improved efficiency and 71% to significant cost savings. There are some concerns regarding the amount of data processing and UAV response in slopes or complex environments. UAVs are transitioning from test equipment to geotechnical equipment of choice, providing real-time actionable information for monitoring, site planning, and hazard analysis. Sensor fusion, artificial intelligence-driven analytics, and normalization of workflow destinies are UAVs to be a major driver of mining digitalization. Future research will focus on underground mapping, automation, and standardization of the regulation to open up the full potential of UAVs across the mining value chain.

Modern aspects of reclamation of coal mines

2026-04-28T14:57:45+00:00

The study aims to identify and systematize the main technical, environmental, and biological factors determining the effectiveness of reclamation of lands disturbed by open-pit coal mining. The research was conducted using documentary analysis and a comparative review of domestic and international practices. Technical and biological reclamation projects for the Severnyi and Vostochnyi coal mines in the Ekibastuz coal basin were analyzed together with published data on the restoration of coal-mining areas in the United States, Mongolia, and Indonesia. The comparison covered engineering preparation of the territory, surface runoff management, erosion prevention, soil and vegetation restoration, environmental monitoring, and the economic feasibility of reclamation solutions. It was established that the two technical reclamation options proposed for the Vostochnyi coal mine differ in the scope and total cost of the planned works. The study showed that flattening the slopes of the Festivalnyi, Konveyernyi, and Prybortovoy external dumps is constrained by the risk of spontaneous combustion of carbonaceous rocks, the location of engineering infrastructure, and the possible expansion of disturbed areas into productive land. Comparison with international experience confirmed the need for long-term monitoring of water quality, backfill stability, vegetation development, and soil-forming processes. It was also found that domestic biological reclamation projects mainly rely on natural revegetation, whereas direct planting and fertilizer application may accelerate the formation of a stable vegetation cover. The main constraints and effectiveness factors associated with the reclamation of large coal mines in Kazakhstan were systematized, and directions for adapting international approaches to the conditions of the Ekibastuz coal basin were identified. The results can be used in the development and revision of reclamation projects that incorporate long-term monitoring, surface runoff control, assessment of soil formation, and active vegetation restoration.

Kinetics of reduction of lead chloride and oxychloride with sodium carbonate

2026-03-10T10:57:01+00:00

This study investigates the kinetic behaviour of the reduction reaction between lead chloride (PbCl₂) and lead oxychloride (PbO·PbCl₂) with sodium carbonate in the presence of carbon in a reducing atmosphere. The relevance of this research stems from the need to develop effective technologies for processing lead-containing secondary production dusts and to optimise the composition of sodium-containing fluxes. Thermodynamic evaluation of the reactions using the Outotec HSC Chemistry software package demonstrated that, within the temperature range of 500-1000°C, both reactions exhibit negative ΔG values and high equilibrium constants, indicating their thermodynamic feasibility. Kinetic studies were carried out using thermogravimetric analysis under isothermal conditions in the temperature range of 800-1100°C for the PbCl₂–Na₂CO₃–C system and 500-800°C for the PbO·PbCl₂–Na₂CO₃–C system. It was established that the reductive interaction proceeds via a multistage mechanism with a change in the rate-controlling step as the degree of conversion increases. For the PbO·PbCl₂–Na₂CO₃–C system, the initial stage of the process is satisfactorily described by the first-order reaction equation, indicating the predominance of chemical control; the apparent activation energy at this stage is 33.5 kJ/mol. As the degree of conversion increases, the activation energy rises to 62-80 kJ/mol, which indicates a transition to a regime complicated by diffusion and structural limitations. The PbO·PbCl₂–Na₂CO₃–C system is characterized by higher reactivity and rapid attainment of significant conversion degrees. At moderate conversion levels, the process proceeds predominantly under chemical control (E_a ≈ 43-44 kJ/mol); however, at α ≥ 55%, an increase in activation energy up to 74 kJ/mol is observed, indicating an increasing influence of mass transfer. It is shown that the presence of oxygen in the structure of lead oxychloride significantly affects the kinetic characteristics of the reductive process in sodium-containing flux systems. The obtained results can be used in optimizing technological schemes for processing lead-containing dusts in order to enhance metal recovery and improve the energy efficiency of the process.

Thermodynamic justification of chloride sublimation of nonferrous metals from chalcopyrite-magnetite ore Irisu in the presence of calcium chloride

2026-02-10T12:58:00+00:00

The presence of nonferrous metals, particularly copper, in the chalcopyrite-magnetite ore of the Irisu deposit precludes its use in metallurgical production. This requires preliminary metal extraction. This article presents the results of a study on the extraction of nonferrous metals from Irisu ore by chloride sublimation roasting. The study was conducted using computer thermodynamic modeling and the HSC-10 software package, which is based on the minimum Gibbs free energy principle. Calcium chloride was used as the chlorinating agent. The effects of temperature and pressure on the chloride sublimation of nonferrous metals and the behavior of iron and sulfur during this process were determined. It was established that the interaction of Irisu ore with calcium chloride is accompanied by the formation of gaseous chlorides: AgCl_(g), CoCl_2(g), Cu₂Cl_2(g), Cu₃Cl_3(g), Cu₄Cl_4(g), CuCl_(g), FeCl_2(g), PbCl_(g), PbCl_2(g), ZnCl_2(g). A decrease in pressure from 0.1 to 0.001 bar reduces the temperature of complete chloride sublimation of copper to 683°C, zinc – 597°C, lead – 593°C, silver and cobalt to 700°C. The degree of chloride sublimation of iron at 700°C is only 0.24%. In the cinder, it is present to a greater extent in the form of Fe₃O₄ and to a lesser extent in the form of Fe₂O₃ and FeO. Under these conditions, sulfur is almost completely (99.99%) converted into SO₂. Chloride sublimates formed at 700°C and 0.001 bar contain 33.94% copper, 11.57% lead, 5.98% zinc, 2.88% cobalt, 0.2673% silver and 5.49% iron. In this polymetallic concentrate, compared to the ore, the content of copper, zinc and silver increased by 44.6 times, lead – by 44.5 times, cobalt – by 45.3 times.

Application Practice of L-SX-EW in the Processing of Copper Ores from Kazakhstan Deposits

2026-03-05T12:26:38+00:00

The article provides an analytical review of the current state and development prospects of Leach-Solvent Extraction-Electrowinning (L-SX-EW) technology within the global and domestic copper industries. The study analyzes the mineral resource base of the Republic of Kazakhstan, including major copper deposits in the East and Central regions. Attention is given to solvent extraction flowsheets, the impact of mineralogical composition, and key technological challenges in processing oxidized and mixed copper ores. The paper highlights the historical role of «VNIItsvetmet» in the development of regional hydrometallurgical technologies and research approaches. The work systematizes data on modern technological schemes and principal efficiency factors of the L-SX-EW process, confirming its vital role in maintaining the long-term competitiveness of Kazakhstan’s copper sector.