Coal Mining Enterprises Research Articles

Comprehensive assessment of factors affecting the operational reliability of low-voltage asynchronous electric motors of a coal mining complex

THE RELEVANCE of this study lies in solving the problem of reliable functioning of elements of energy systems and ensuring their effective operation during open-pit mining. The paper presents a methodological approach that allows us to assess the level of reliability of low-voltage asynchronous electric motors in a coal mine with complex mining, geological and climatic conditions of production. THE PURPOSE of the work is to quantify the operational factors affecting the service life of an asynchronous electric motor with a short-circuited rotor. Attention is focused on how influencing factors, different in physical basis, among which electrical parameters are highlighted – the coefficient of voltage asymmetry in the reverse sequence, the coefficients of harmonic voltage components and environmental parameters – temperature, air humidity and dustiness, affect the dynamics of changes in the service life of an asynchronous electric motor. Asynchronous electric motors used at one of the enterprises of JSC SUEK in the Trans-Baikal Territory are considered as an object of research. METHODS. The main tool for the implementation of research tasks is computer modeling based on the Matlab software package. RESULTS. The studies were performed on an asynchronous electric motor with a short-circuited rotor with Ph = 3 kW, rated speed 1500 rpm. The simulation of the operating mode of the electric motor under study was performed by changing the experimental parameters: the values of the total coefficient of harmonic voltage components (KU) – from 4 to 12% with a range of 2%; the values of the voltage asymmetry coefficient in the reverse sequence (K2U) – from 0 to 4% with a range of 1%; the ambient temperature (∆Tокr) – from -30°C to +30°C with a range of 10°C; air humidity values (Vc) – 20% and 60%; dust thermal conductivity coefficient values (Kт) – 0,12 and 0,28. Based on the obtained research results, diagrams are constructed that clearly illustrate the dynamics of changes in the service life of an asynchronous electric motor depending on the combination of influencing factors. CONCLUSION. The trends in solving the issues of reliable functioning of a coal mining enterprise with the presence of asynchronous electric motors and ensuring their efficient operation are the most priority, mainly focused on maintaining the stability of technological processes and maintaining the production volumes of a coal mining enterprise. The stability of the electric motor to certain influencing factors is estimated and their critical values are established. Recommendations on the use of asynchronous electric motors are formulated, taking into account their operating conditions.

Research on High-Frequency Isolated NPC Three-Level Inverter for Frequency Conversion and Speed Regulation

Mining frequency converters are the primary means for achieving variable frequency speed regulation of electromechanical equipment in coal mines, offering energy-saving benefits for coal mining enterprises. The common power supply method involves converting high voltage to low voltage using power frequency transformers before supplying equipment. However, this integration of power frequency transformers with supply devices occupies significant space, making it unsuitable for confined underground environments. Additionally, they suffer from poor output waveform quality and high harmonic content. To tackle these challenges, this paper presents a three-stage topology for high-frequency isolated frequency conversion and speed regulation, utilizing three-phase uncontrolled rectification, a single active isolated DC/DC converter, and an NPC three-level inverter. The control strategies for each stage are discussed in detail. Simulations and experimental results confirm the validity and feasibility of the proposed design, demonstrating enhanced stability and dynamic performance of the three-stage high-frequency isolated frequency converter.

Research on the mechanism of human-machine security collaboration of miners considering automation trust

Safety in the coal mining industry is a long-standing issue. With the implementation of intelligent construction in coal mines, humans–machine collaboration is critical to accident prevention. We investigate the psychological dynamics among miners during intelligent construction by developing distinct evolutionary game models for miner security collaboration mechanisms, while also considering the level of trust in automation. We explore the impact of changes in automation trust on the human–machine security collaboration behaviour among miners as well as the regulatory strategies adopted by coal mining enterprises. Evidently, the current level of automation trust among miners is insufficient to ensure safety, and the safety management systems of coal mining enterprises are yet to reach a stable state. Examination of the relevant parameters using specific examples reveals that the optimal range for the level of automation trust among miners lies between 0.7 and 0.9, indicating a favourable coal mine safety production system. These conclusions provide a scientific foundation for effectively enhancing safety management in the context of intelligent construction in coal mines.

Association between urinary mixture metal levels and olfactory function in coal miners.

Exposure to occupational metallic mixtures has a potential impact on olfactory function. However, research evidence is limited on the potential impact of exposure to metallic mixtures and olfactory dysfunction. Furthermore, the coal dust generated contains multiple various metals during coal mining, and no study yet has focus on the olfactory dysfunction of coal miners. In this study, we evaluate the association between urinary metallic mixtures and olfactory function in coal miners, while also exploring the potential applicability of plasma olfactory marker protein (OMP) as a biomarker for assessing olfaction. From July to October 2023, coal workers from seven different coal mining enterprises were recruited for the survey when they come for the employee health checkup. Ultimately, 376 participants were met the inclusion criteria and, respectively, determined with the concentrations of urine (16 metals) and plasma (OMP). Meanwhile, applying UPSIT to access their olfactory function. Binary logistic regression and restricted cubic spline (RCS) model were used to estimate the association of individual metals with olfactory function. Bayesian kernel machine regression (BKMR) and Quantile g-computation (QG-C) regression were employed to assess the overall association between metal mixtures and olfactory function and identify the major contributing elements. In a single-metal model, two metals in urine were found to be significantly associated with olfactory function. RCS analysis further revealed that the association between Iron (Fe) and olfactory function was linear, while Lead (Pb) exhibited a non-linear. The BKMR model demonstrated a significant positive association between metal mixture concentration and olfactory function. Combined QG-C regression analysis suggested that metals Cr, Fe, Se, Sb, and Pb could impact the performance of the olfactory test (UPSIT), with Pb being identified as the most influential contributor. The correlation between plasma OMP protein levels and urinary metal concentrations was weak. Multiple metals are associated with olfactory function in the coal miners. A significant positive association was observed between metal mixture concentrations and olfactory function, with Pb being the most important contributor. In this study, plasma OMP has not been demonstrated to serve as a biomarker for olfactory function.

Evaluation of Possibilities for Effective Accounts Receivable Management in Coal Mining Enterprises

Evaluation of Possibilities for Effective Accounts Receivable Management in Coal Mining Enterprises

The Multi-level Hierarchical Structure Analysis of Influencing Factors of Coal Mine Managers' Blame Avoidance Behavior

BackgroundIn the Chinese coal industry, widespread blame avoidance behavior (BAB) greatly impacts coal mine accidents. Therefore, it is necessary to stop the BAB of coal mine managers and raise the management level of coal mine enterprises for the safe development of Chinese coal industry. MethodsBased on the semi-structured interviews and questionnaire surveys (20 middle-level managers in coal mines), this paper used the Grounded Theory and Nvivo Software qualitative research methodology to open, spindle, and selectively encode the interview data. Then, an index system of factors influencing BAB of coal mine managers was constructed. The influence degree, affected degree, centrality degree, cause degree of each influencing factor were calculated and the hierarchical model of influencing factors of BAB of coal mine managers was established by the DEMATEL-ISM method which is a decision support tool used to evaluate and analyze the interdependencies between influencing factors. ResultsIndex system of factors influencing BAB of coal mine managers included four levels and 12 influencing factors: individual, organizational, institutional environmental, and situational factors. The hierarchical model identified eight causal factors and four consequential factors, of which safety management (15.355), work attitude (14.380), and work group performance (14.281) in the top three of the centrality rankings are the key factors affecting the avoidance behavior of coal mine managers; A 3-level multilevel structure was constructed to reflect the interactions among the factors influencing the BAB of coal mine managers in terms of direct, indirect, and root causes, and corresponding improvement measures were proposed. ConclusionThis study offers a theoretical complement and practical guidance for stopping BAB of coal mine managers.

Энергосбережение и оценка энергоэффективности угледобывающего предприятия

The article is devoted to consideration of issues related to assessing the energy efficiency of a coal mining enterprise. Coal mining enterprises are characterized by a large volume of energy intensive ore mining operations. The article presents possible ways of energy saving in the mining industry. During the research, a system of energy efficiency indicators for coal mining enterprises is presented. Materials and methods. The article proposes a system of indicators for coal enterprises based on existing methods and approaches to assessing energy efficiency. Energy consumption dependence graphs, benchmarking, and pinch analysis are considered as a starting point. Results. The study presents a system of energy efficiency indicators for coal mining enterprises. The proposed system has several levels. The existing methods and approaches for assessing this important indicator for industrial enterprises in the coal industry as a whole are considered. The author’s approach to formalizing the system of energy efficiency indicators for coal mining enterprises is proposed. The significance of energy audit as a key assessment measure is indicated and its stages are highlighted. The influencing factors determining energy costs and their reduction for a coal mining enterprise are systematized, barriers preventing the practical implementation of energy saving measures are analyzed. Discussion. The proposed metrics system provides a comprehensive framework for assessing the energy efficiency of coal mining enterprises at various levels. Its flexibility allows it to be applied to the analysis of individual equipment units, production processes, and overall enterprise performance. Its multi-level approach provides a detailed understanding of energy consumption, which allows for informed decision-making to optimize operations. At the equipment level, the metrics system evaluates the energy consumption and efficiency of individual machines and devices. At the production process level, the metrics system analyzes the energy consumption and efficiency of various stages of coal mining. At the enterprise level, the metrics system provides a comprehensive assessment of overall energy efficiency. It takes into account energy consumption at all levels and allows enterprises to compare their performance with each other and with industry benchmarks. Conclusion. Energy efficiency assessment of a coal mining enterprise allows to understand how and where energy is used, where its use can be improved, and how to reduce its costs. To conduct an energy efficiency assessment, the article proposes a system of indicators, highlighting the features of an energy audit. The main advantage of the proposed system of indicators is that it covers a wide range of energy consumption indicators, which are carefully selected and located at different levels of detail. In general, a balanced approach to the level of detail and generalization in the system of indicators provides flexibility in adapting indicators to specific research questions and helps to interpret the results in the context of structural differences between energy systems. Resume. Overall, the proposed metrics system offers a comprehensive approach to analyzing the energy efficiency of coal mining enterprises, covering all levels of operations. Its use allows enterprises to improve energy efficiency, reduce operating costs, and contribute to a more sustainable coal mining industry. Suggestions for practical applications and directions for future research. The use and implementation of the developed system at a coal mining company allows it to improve energy efficiency, reduce operating costs and contribute to a more sustainable coal mining industry.

Visualization Method on The Cognition and Decision-Making of Core Personnel in Coal Mines: Basis for Strategic Plan

This research analyzed the application of visualization methods and systems in core positions in four coal mining enterprises with a long history, as well as their impact on the cognitive load and decision-making behavior performance of core employees. It explored their achievements in process reengineering and system optimization, analyzed their impact on safety production, production costs, and profitability, and shaped core business and competitive advantages to achieve corporate strategy. The research recognized that， firstly, the scope of visualization methods and systems was clear, the structure was orderly, and the implementation was appropriate, laying the foundation for subsequent research. Secondly, the visualization methods have a positive impact on employee cognitive load, decision-making behavior, and performance, and can promote information and knowledge dissemination. Visualization methods transmit the impact on core employees to process optimization and system transformation, thereby achieving visual control of risk sources and reducing safety accident rates. Thirdly, coal mining enterprises face challenges in high-dimensional visualization research and development, system integration, privacy protection, data security, as well as adapting to future business development and talent teams. And proposed a strategic plan to address these challenges. At the end of the paper, suggestions were made for the application of visualization methods in coal mining enterprises.

Оценка хозяйственных рисков при реализации технологий угледобычи в современных условиях недропользования

Introduction. This paper presents research in the field of methodology of assessment and monitoring of associated under ground coalmining risks in order to level their impact on the resulting technical and economic indicators of production and economic activities in modern conditions of subsoiluse. The functioning of technological systems of coal mining enterprises at the present stage of subsurface use occurs in a highly dynamic and highly variable functional environment with a fair degree of uncertainty, which is generated by a significant variety of parameters and characteristics of the initial mining, geological and mining engineering environment, which, in turn, generates the emergence of various groups and risk factors for subsurface use. The established procedures and methods of risk forecasting currently do not give satisfactory results due to the globalization of world markets and high volatility of prices for coal products. Leveling the negative degree of influence of the risk component on the resulting indicators – indicators of technical and economic activity can be achieved through the introduction of an operational system for assessing and monitoring various groups of risk factors. Materials and methods. For the purpose of evaluation, it is proposed to use the methodological and methodological foundations of the method called “vector norms”, which involves the use of Affine space, the constituent areas of compromises and the introduction of utility estimates. A complete model representation of the assessment and monitoring of the impact of various risk factors of subsurface use, taking into account their clustering and ranking, is presented. The algorithmic support of this method is reduced to the following components-iterations: 1. Formation of criteria-based assessment matrices of various factors of subsurface use risk groups. 2. Assignment of optima to evaluation criteria. 3. In order to ensure the legality of the use and implementation of mathematical procedures and operations, the reduction of multi-dimensional evaluation criteria to a relative form, taking into account the assigned optima. 4. Formation of the objective function of the “norm of the vector” (integral indicator) and the development of a procedure for selecting the optimal option. Since the use of the methodological and methodological foundations of the method called “vector norms” allows us to form quantitative estimates of the presented factors-types of risk of subsurface use, this makes it possible to implement the clustering procedure or ranking of a selected set of coal mining enterprises in conjunction with existing risk areas. Results. Quite high values of correlation coefficients were obtained with a significant closeness of the relationship of inversely proportional dependencies of generalizing integral indicators of the degree of risk and the level of achievement of planned indicators and development of production capacity with the level of operational profitability from the conduct of production and economic activities of coal mining enterprises with a directly proportional dependence on the operating costs of mining 1t of coal. Discussion. Сomplete model representation of the assessment and monitoring of the impact of various risk factors of subsurface use, taking into account their clustering and ranking, is presented. As a practical component of the research, variable series of areas of integral degree of risk in the functional environment of Kuzbass coal mines are presented. The use of software modules for correlation and regression analysis, taking into account three-year retrospective dynamics, made it possible to establish the legality and objectivity of the proposed methodological apparatus for integrated risk assessment of the implementation of coal mining technologies in modern conditions of subsurface use. Conclusion. The results of the implementation of the theoretical components of the methodology and model representations of the developed conceptual foundations for the integrated risk assessment of the implementation of coal mining technologies in modern conditions of subsurface use, taking into account five-year retrospective dynamics, showed that in the Kuznetsk basin there was a steady tendency to reduce the cluster of coal mines, which is characterized by high risks of carrying out production and economic activities in the presence of a disproportion of resource potential (the emergent part). The accompanying processes of formation of this trend are manifested in a quantitative increase in the functional units of the rating cluster of group 2B with an average resource potential and inherent moderate risk. It is within this cluster that strategies for prioritizing investments for the development and renewal of technological systems and structures of coal mining are being formed, since only they are able to provide the fastest possible return on invested funds. Resume. The article presents the results of research in the field of methodology for assessing and monitoring the risks associated with underground coal mining in order to level out their impact on the resulting technical and economic indicators of production and economic activity in modern conditions of subsoil use. The research results can be useful in the implementation of coal mining technology in modern conditions of subsoil use.

Coal in the 21st century: Industry transformation and transition justice in the phaseout of coal-as-fuel and the phase-in of coal as multi-asset resource platforms

The coal industry is enjoying long-term investments in new coal-fired power generation even as coal mining and production have been declining. Recent conflict in Europe has disrupted energy supplies and reinvigorated coal use. The duration of the retrenchment to coal may be short lived, but the end point of “short lived” remains uncertain. The present state of the coal industry and the investment community that underpins its growth obviates any meaningful acceleration in coal's phaseout as a core fuel resource. However, coal can be recast as a catalyst for achieving clean energy and economy futures. This can be done by seeing coal hydrocarbon deposits and byproducts of coal processing as long-term multi-asset resource platforms (MARPS), which integrate multiple new revenue streams on coal lands other than just mining coal as a fuel. New value comes from repurposing and leveraging mining lands, harvesting minor and trace elements from coal, and creating new revenue from harvesting hydrogen and carbon materials from coal bed methane, raw coal, coal tailings, and fly ash residues. We make the case that Coal Mining Enterprise (CME) value can be enhanced by ending the use of coal-as-fuel and creating new value streams serving existing and emerging markets by fully assessing, evaluating, and utilizing the portfolio of natural resources that are collocated within a typical coalfield. Coal sector investors tend not to see undervaluation in coal assets because CMEs focus predominantly on mining, processing, and shipping coal-as-fuel for electricity production and industrial processes. Formulating and asking the correct questions about how much value is being left on the table may bring innovation into a new frontier of coal as multi-asset resource platforms. Co-benefits of the approach include job creation across many viable emerging markets where “refining” coal is a competitive source of factor inputs. Moreover, it aids governments in aggressive support of coal industry transformations, through which lasting coal transition justice can be achieved. Ironically, despite all the technological and market uncertainties, coal in the 21st century can be, and should be, a critical success factor in achieving clean energy and economy futures.

Modern distributed production (manufacturing) as an important part of the future Ukrainian nationally rooted industry

The purpose of this paper is to propose a variant for the development of a part of the national industry, which would be free from the problems of large investments and threats of unprofitability against the background of innovations. Before the full-scale war, which began in 2022, Ukrainian industry was an offspring and a powerful part of the Soviet heavy industry, mainly of the third technological order. Now, the enterprises that were powerful generators of the national economy GDP are to a greater extent located in the temporarily occupied or front-line territory. Industrial regions suffered significant damage to the production base and infrastructure facilities. The post-war restoration of the domestic industry requires large capital investments, which the national economy is not capable of. In addition, there is a limitation on the duration of investment projects due to the rapid development of modern technologies. According to experts, any project whose implementation exceeds 3 years is risky. In addition, there is a Marxian tendency of the rate of profit to decrease, due to a change in the capital structure, in particular, a decrease in labor expenses. Modern processes of mechanization of production, increase of innovative components (computerization, Internet of things, digitalization, etc.) increase the risks of unprofitability. The authors give an example of the closure of coal mining enterprises in European countries against the background of scientific and technical progress. At the same time, based on the analysis of literary sources, the trend of the spread of the DIY 4.0 phenomenon (from Do It Yourself) was revealed – the use of the most modern technological elements for the manufacture of products designed to meet the manufacturers' own needs. Especially in the USA, the Maker Movement, which is a new culture of industrial activity, is developing. The article substantiates that the technological base of DIY 4.0 and the culture of the Maker Movement are the foundation of the new distributed manufacturing, free from the "curse" of mass investment and unprofitable innovation. It is distributed manufacturing that is able to fundamentally change the quality picture and structure of industry, to ensure the national rooting of industrial production.

Performance Analysis and Optimization of Solar-Coupled Mine Water-Source Heat Pump Combined Heating and Cooling System

To address the energy consumption issue in mining area buildings, this paper proposed a solar-coupled mine water-source heat pump combined heating and cooling (SMWHP-CHC) system, taking the employee dormitory building group of a coal mining enterprise in Tongchuan City, China, as a case study. The system utilizes renewable solar energy and waste heat recovered from mine water as composite heat sources, and utilizes the cold energy in mine water as a cooling source to meet the demands for space heating, space cooling, and annual domestic hot water of the building in a sustainable manner. The simulation model of the system was established by TRNSYS to analyze the system’s annual operational performance. The results indicated that the system exhibited a positive energy efficiency and environmental performance under different operating conditions. The heating coefficients of the performance of the system (COPsys) during the space heating season and transition season were 3.54 and 18.6, and the cooling energy efficiency ratio of the system (EERsys) was 3.79. In addition, aiming to minimize the annual cost of the system, multiple crucial device parameters were synchronously optimized employing the PSO-HJ hybrid optimization algorithm through the GenOpt 2 software. The annual cost of the optimized system was reduced by 8.82%, and the investment cost was significantly reduced, while the performance was also improved. This study can provide theoretical support for the sustainable engineering application of the SMWHP-CHC system in mining area buildings.

Promoting Sustainable Coal Gas Development: Microscopic Seepage Mechanism of Natural Fractured Coal Based on 3D-CT Reconstruction

Green mining is an effective way to achieve sustainable development in the coal industry. Preventing coal and gas outburst dynamic disasters are essential for ensuring sustainable and safe mining. The numerous microscopic pores within the coal serve as the primary storage space for gas, making it critical to explore the structural distribution and seepage characteristics to reveal the disaster mechanism. Under mining stress, gas within the micropores of the coal migrates outward through cracks, with these cracks exerting a significant control effect on gas migration. Therefore, this study focuses on utilizing natural fractured coal bodies as research objects, employing a micro-CT imaging system to conduct scanning tests and digital core technology to reconstruct sample pore and fracture structures in three dimensions, and characterizing the pores, cracks, skeleton structure, and connectivity. A representative elementary volume (REV) containing macro cracks was selected to establish an equivalent model of the pore network, and a seepage simulation analysis was performed using the visualization software. Revealing the seepage characteristics of fractured coal mass from a microscopic perspective. The research results can provide guidance for gas drainage and dynamic disaster early warning in deep coal mines, thus facilitating the sustainable development of coal mining enterprises.

Characterization of gas hydrate generation in SDS-R141b compounding static system

Characterization of gas hydrate generation in SDS-R141b compounding static system

Application of Free Ball Check Valve Mixed Grouting Device

In recent years, due to the uneven water abundance of the aquifer and the complexity of the underground seepage field, the grouting reconstruction project of coal mining enterprises is more difficult. The previous method is to install a high-pressure ball valve before the grouting pipe connected to the grouting pump is connected to the mixing device, which can be manually adjusted when the number of grouting pumps needs to be changed. However, under certain pressure, the ordinary high-pressure ball valve often fails due to the influence of high-pressure mixed slurry, cement solidification and wear, and the number of grouting pumps cannot be increased or decreased in real time. In order to solve the problem that the mixing device of traditional grouting system is easy to fail by using ordinary high-pressure ball valve, the mixing device of free ball check valve was developed and applied in the process of treating the Ordovician limestone aquifer area on the floor of No.9 coal seam in Xipang Well. The practical results show that the pipeline can be automatically closed when a single grouting pump stops grouting, and there is no need to flush the grouting pipeline with a large amount of water, which can improve the grouting efficiency and quality, and the influence time of single hole section is reduced from 8.25h to 0.34h. The process performance can meet the requirements of efficient grouting.

A Case Study of Accident Analysis and Prevention for Coal Mining Transportation System Based on FTA-BN-PHA in the Context of Smart Mining Process

In the face of the increasing complexity of risk factors in the coal mining transportation system (CMTS) during the process of intelligent transformation, this study proposes a method for analyzing accidents in CMTS based on fault tree analysis (FTA) combined with Bayesian networks (BN) and preliminary hazard analysis (PHA). Firstly, the fault tree model of CMTS was transformed into a risk Bayesian network, and the inference results of the fault tree and Bayesian network were integrated to identify the key risk factors in the transportation system. Subsequently, based on the preliminary hazard analysis of these key risk factors, corresponding rectification measures and a risk control system construction plan are proposed. Finally, a case study was carried out on the X coal mine as a pilot mine to verify the feasibility of the method. The application of this method effectively identifies and evaluates potential risk factors in CMTS, providing a scientific basis for accident prevention. This research holds significant importance for the safety management and decision making of coal mine enterprises during the process of intelligent transformation and is expected to provide strong support for enhancing the safety and reliability of CMTS.

Research on the evaluation of the operating effectiveness of the safety double prevention mechanism of coal mine enterprises based on matter-element extension

Safety production is a crucial guarantee for the country's economic development, and the safety double prevention mechanism is an effective way to realize safety production. In order to improve the operating effectiveness of coal mine enterprises' safety double prevention mechanism, this paper preliminarily constructs the evaluation indicator system for the operating effectiveness of the safety double prevention mechanism of coal mine enterprises based on the accident cases and literature analysis. The questionnaire was designed according to the index system, and the reliability and validity of the recovered data were analyzed. Based on the results of the analysis, the index system for evaluating the operating effectiveness of the safety double prevention mechanism of coal mine enterprises is established. This system comprises five first-level and 30 second‐level indicators for risk hierarchical control, hidden danger investigation and treatment, inspection review and update, employee safety management, and safety guarantee management. Subsequently, this paper utilized the AHP-EWM to empower the evaluation indicators and then constructed the matter-element extension model to evaluate the operating effectiveness of coal mine enterprises' safety double prevention mechanism. Finally, the Y coal mine enterprise is an example of empirical analysis. The results show that the operating effectiveness of the Y coal mine enterprise's safety double prevention mechanism has generally reached a good level. However, some evaluation indicators still have a low evaluation level, which is consistent with the actual situation of the Y coal mine enterprises. Evaluation results verify that this paper's evaluation indicators and model have strong applicability and scientificity.

The impact of identity conflicts among Chinese knowledge-based miners on unsafe behavior: A moderated chain mediation model.

In the context of smart mine construction, coal mine safety management is imposing stringent requirements on the safety competence of miners. To meet these demands, coal mine enterprises have initiated proactive measures to recruit a new generation of knowledge-based miners who possess high qualifications and specialized backgrounds. This study aims to explore the underlying mechanisms of identity conflict (IC) and its influence on unsafe behavior (USB) among KBMs within the context of China's smart mining initiatives, as well as to identify the role of potential mediating and moderating variables in this relationship. An empirical study was conducted on a sample of 304 KBMs with a college degree or above, selected from multiple coal mines in Shanxi Province, China. Hierarchical regression analysis and the Bootstrap method were employed for data analysis. This model incorporated IC as the antecedent variable and meticulously investigated the mediating effects of role breadth self-efficacy (RBSE) and psychosocial resources (PSR), along with the moderating effect of positive explanatory bias (PEB). The findings indicate a significant positive correlation between IC and USB among KBMs. RBSE and PSR were found to mediate the relationship between IC and USB. Moreover, this mediating effect further influenced the relationship between IC and USB through a chain mediating effect. Additionally, PEB strengthened the positive impact of KBMs' RBSE on PSR. These results provide a broader perspective on the antecedent variables associated with KBMs' USB and provide valuable insights and practical management strategies enhancing the safety management practices within coal mining enterprise.

Evaluation of risk factors affecting the safety of coal mine construction projects using an integrated DEMATEL-ISM approach

Purpose The purpose is to identify and evaluate the safety risk factors in the coal mine construction process.Design/methodology/approach The text mining technique was applied in the stage of safety risk factor identification. The association rules method was used to obtain associations with safety risk factors. Decision-Making Trial and Evaluation Laboratory (DEMATEL) and Interpretative Structural Modeling (ISM) were utilized to evaluate safety risk factors.Findings The results show that 18 safety risk factors are divided into 6 levels. There are 12 risk transmission paths in total. Meanwhile, unsafe behavior and equipment malfunction failure are the direct causes of accidents, and inadequate management system is the basic factor that determines the safety risk status.Research limitations/implications Due to the limitation of the computational matrix workload, this article only categorizes numerous lexical items into 18 factors. Then, the workshop relied on a limited number of experts; thus, the findings may be potentially biased. Next, the accident report lacks a universal standard for compilation, and the use of text mining technique may be further optimized. Finally, since the data are all from China, subsequent cross-country studies should be considered.Social implications The results can help China coal mine project managers to have a clear understanding of safety risks, efficiently carry out risk hazard identification work and take timely measures to cut off the path of transmission with risks identified in this study. This helps reduce the economic losses of coal mining enterprises, thus improving the safety standards of the entire coal mining industry and the national standards for coal mine safety policy formulation.Originality/value Coal mine construction projects are characterized by complexity and difficulties in construction. Current research on the identification and assessment of safety risk factors in coal mine construction is insufficient. This study combines objective and systematic research approaches. The findings contribute to the safety risk management of China coal mine construction projects by providing a basis for the development of safety measures.

Study of carbon materials using X-ray diffraction method, qualitative and quantitative analysis of adsorption

Active carbons are porous industrial adsorbents and carbonaceous materials derived from various organic raw materials and used to treat drinking and waste water. This study aimed to X-ray analyzes the structure of the sorbent based on coal and the efficiency of ion extraction from solutions by this sorbent. The diffraction patterns of the sorbents were obtained on a powder diffractometer. The qualitative and quantitative composition of the sorbents was determined by X-ray fluorescence method. The sorbent surface was imaged using scanning electron microscopy. It was found that the isotherms of the studied systems are satisfactorily described by the Langmuir and Freundlich models. The constants of the Freundlich equation were 0.31, 0.004, and 0.029 for adsorption of iron ions, manganese ions, and nitritions, respectively. The maximum adsorption of Langmuir iron ions was 3.61 mg/g, manganese ions 2.49 mg/g, and nitrite ions 0.33 mg/g. The Gibbs energy during adsorption of iron ions, manganese ions and nitrite ions were −17.93 kJ/mol, −30.5 kJ/mol and −20.5 kJ/mol, respectively. It is shown that effective extraction of ions can occur due to ion exchange and complexation processes for metal ions with active centers on the sorbent surface. Development of the technology of treatment of open-pit and surface wastewater of coal mining enterprises using sorbents based on coal will allow to solve environmental problems of resource-oriented regions and will contribute to the restoration and ecological rehabilitation of water bodies.