Coal Mining System Research Articles

Enhancing gas drainage and ventilation efficiency in underground coal mines: A hybrid expert decision approach for booster fan prioritization

Expanding mining operations in goaf zones heightens gas production potential, posing challenges in maintaining adequate ventilation within development panels, consequently impacting coal production. Various strategies have been explored to enhance mine ventilation and gas drainage effectiveness. However, deficiencies persist in the proposed ventilation system for the Okaba underground coal mine, prompting this study’s necessity. Addressing these concerns, the study evaluates the feasibility of employing booster fans to mitigate the identified drawbacks. Prioritizing booster fans for airflow distribution in underground mines is a complex decision-making process, requiring an advanced expert system approach. To address this, the study proposes an intuitionistic-based fuzzy TOPSIS (IFT) method for booster fan prioritization in the Okaba mine. Results indicate that booster fan 4 (BF4) ranks highest, followed by booster fan 3 (BF3), consistent with fuzzy TOPSIS findings. Sensitivity analysis supports the predicted importance order, affirming the efficacy of the hybrid expert decision method in selecting a booster fan capable of enhancing the overall efficiency of gas drainage and ventilation systems in underground mines. This study introduces a Hybrid Expert Decision Approach that integrates IFT and traditional fuzzy TOPSIS methodologies. This hybrid approach is particularly novel because it combines the strengths of both methods to prioritize booster fans in underground coal mines.

Application and Prospect of Strapdown Inertial Navigation System in Coal Mining Equipment.

In recent years, with the rapid construction of a safe, clean, efficient and sustainable modern energy system, the intelligence of coal mining has become the inevitable direction of the development of the coal mining industry. The intelligence of coal mining system and equipment is the core of intelligent mining, and the positioning technology of mining equipment is the key to underground intelligent mining. The strapdown inertial navigation system can make up for the shortcomings of traditional GPS positioning systems and laser positioning because of its strong anti-interference, high precision and real-time monitoring, and ability to carry out real-time dynamic positioning of mining equipment in underground coal mines. This paper briefly introduces the basic principle of the strapdown inertial navigation system, analyzes the application of the existing strapdown inertial navigation system in mining equipment, and lists and analyzes the research status of the improvement strategy of the inertial navigation system, such as zero speed correction and integrated navigation technology. Finally, by analyzing the application and future development trend of inertial navigation systems in mining equipment, this paper provides more data and method support for the positioning of mining equipment in the future.

IoT Based Smart Helmet for Coal Mining and Safety Monitoring System

IoT Based Smart Helmet for Coal Mining and Safety Monitoring System

Breaking law of overburden rock and key mining technology for narrow coal pillar working face in isolated island

When conducting retreat mining in segmented coal pillars, the dynamic evolution of stress and overlying strata structure is more complex than conventional working faces due to the influence of adjacent working faces. Understanding and mastering the dynamic evolution patterns of overlying strata structure after retreat mining in segmented coal pillar working faces is essential for guiding the safe recovery of coal pillar resources under similar conditions. Through statistical analysis of the types of residual coal and the mining techniques, the current research status of residual coal mining system in China has been summarized. Based on the safety recovery technology system for multi-type residual coal pillar resources at Zhaogu No.2 Mine, this paper focuses on narrow coal pillar working faces in sections with fully mined-out areas on both sides. By using research methods such as on-site measurement, theoretical analysis, numerical simulation, and engineering experiments, starting from the stress state analysis and evolution law of coal seam mining, the dynamic evolution law of the overlying rock structure of sectional coal pillars has been mastered. On this basis, a stress arch mechanical model of the mining area is constructed, and the working resistance of the support is calculated and determined, ensuring the safe recovery of the working face. The research results show that before the backfilling of the sectional coal pillar working face, the working face is affected by the overlapping mining of the goaf on both sides, presenting a “bimodal” stress distribution pattern, with a stress concentration coefficient between 1.78 and 3.2. After the extraction of segmented coal pillars, stress arches consisting of high-stress zones form along both the strike and dip of the working face. The structural support provided by stress arches undergoes a dynamic evolution process of “formation-development-elevation-stabilization” as the working face advances. Following the instability and rupture of the lower basic roof hinge structure, the stress-bearing structure shifts to the higher basic roof, continuing to provide support for the surrounding rock stress in the mining space of the working face. A stress arch mechanical model for the dip and strike of the mining area is constructed , and the shape characteristics of the overlying rock stress arch in the coal pillar working face is mastered. Based on the stress distribution law and stress arch evolution characteristics of the surrounding rock of the coal pillar working face, the maximum working resistance of the support in the working face is theoretically calculated to be 9153.48kN. Compared with the measured mine pressure data, the selected support effectively ensures the safety production of the working face.

Anthropogenic processes drive spatiotemporal variability of sulfate in groundwater from a multi-aquifer system: Dilution caused by mine drainage

The water quality evolution of surface and groundwater caused by mining activities and mine drainage is a grave public concern worldwide. To explore the effect of mine drainage on sulfate evolution, a multi-aquifer system in a typical coal mine in Northwest China was investigated using multi-isotopes (δ34SSO4, δ18OSO4, δD, and δ18Owater) and Positive Matrix Factorization (PMF) model. Before mining, the Jurassic aquifer was dominated by gypsum dissolution, accompanied by cation exchange and bacterial sulfate reduction, and the phreatic aquifers and surface water were dominated by carbonate dissolution. Significant increase in sulfate in phreatic aquifers due to mine drainage during the early stages of coal mining. However, in contrast to common mining activities that result in sulfate contamination from pyrite oxidation, mine drainage in this mining area resulted in accelerated groundwater flow and enhanced hydraulic connections between the phreatic and confined aquifers. Dilution caused by the altered groundwater flow system controlled the evolution of sulphate, leading to different degrees of sulfate decrease in all aquifers and surface water. As the hydrogeochemical characteristic of Jurassic aquifer evolved toward phreatic aquifer, this factor should be considered to avoid misjudgment in determining the source of mine water intrusion. The study reveals the hydrogeochemical evolution induced by mine drainage, which could benefit to the management of groundwater resources in mining areas.

Application and Research of Microseismic Monitoring System and Hydraulic Fracturing Technology in Coal Mines

In order to improve the effectiveness of coal mine gas control and enhance the level of coal mine safety production, the application of a microseismic monitoring system and hydraulic fracturing technology in coal mines was studied. Applying hydraulic fracturing technology to coal mine gas treatment, firstly, the geological structure and gas concentration in the mining area are detected using the radio tunnel perspective method and infrared differential absorption method. Then, the relevant parameters of hydraulic fracturing are determined, and finally, hydraulic fracturing technology is implemented. Microseismic monitoring technology is used to monitor the cracks formed during hydraulic fracturing construction and evaluate the fracturing effect. The instantaneous energy envelope is obtained from the microseismic data of each detection channel after stacking and Hilbert transform static correction. A microseismic in-phase inversion positioning objective function based on travel time residuals is constructed, and under the constraints of polarization analysis, the optimal solution is obtained through search iteration to complete microseismic in-phase inversion positioning. Experimental results have shown that after applying this method to coal mine gas control, the gas concentration decreases below the execution standard, achieving good control effects. Under microseismic monitoring in coal mines, the hydraulic fracturing effect can be effectively and reasonably evaluated, and the safety production level of coal mines can be improved.

A Constraint Adaptive Multi-Tasking Differential Evolution Algorithm: Designed for Dispatch of Integrated Energy System in Coal Mine

A Constraint Adaptive Multi-Tasking Differential Evolution Algorithm: Designed for Dispatch of Integrated Energy System in Coal Mine

Optimizing coal mine planning and design for sustainable development in the context of mass exploitation of coal deposits

Sustainable mining practices is a concept that embeds the principles of sustainable development into the whole mine life-cycle, from exploration, extraction and processing through to mine closure. The optimization of coal mine planning and the developing a standardized design for its sustainable development is very challenging and requires more effort. The present research attempts to address the conditions of sustainability and necessary measures for sustainable development, thereby providing appropriate solutions for each stage of mining operation besides expressing the necessity of sustainable development integration at different stages of mining life cycle (MLC). The approach of systems engineering is essential to assist the sustainability goals which are integrated with the expected results. Hence a method depending more on systems engineering principles and optimization can be incorporated to attain better results. Several socio-environmental factors associated with sustainability depends on the geographic condition and few mining engineering considerations such as mine location, topography, coal seam characteristics and so on. These systems engineering approach can be further enhanced by incorporating tools like Geographic Information System (GIS), which provides more accuracy and precision of the geographic conditions of the site identified for the coal mining plan. In order to begin this way of approach towards the sustainability development and mining planning, the appropriate optimization parameters should be identified. The outcome of these optimization parameters can be also achieved by optimizing coal mining system models.

Research on mine ventilation network solution and collaborative control technology

With the development of intelligent ventilation system in domestic coal mines, the demand for ventilation network solving software is becoming more and more intense. Aiming at the problem that the traditional ventilation network solution algorithm is difficult to meet the increasingly complex ventilation system solution needs of domestic mines, and the lack of functions of the collaborative control of ventilation equipment and facilities, this paper uses theoretical analysis combined with mine reality to study the relevant theories and algorithms in the field of ventilation network solution and collaborative control at home and abroad, and optimizes the network solution and collaborative control related algorithms such as iterative calculation of ventilation network, identification and stability analysis of angle-linked wind network, natural wind pressure calculation, local fan collaborative control, and collaborative control of damper and wind window. Provide theoretical guidance for future network solution software development.

A novel index for shearer system resilience in underground coal mines based on the operational environment

The use of resilience during the mining period by guaranteeing the safety and performance of the systems greatly helps the managers and engineers with their decision-making and designing different systems. During the last two decades, various studies have been conducted in this regard. However, the analysis of underground coal mining systems’ resilience has been rarely addressed by these studies. The present study aims to provide a quantitative index for resilience in the environment of underground coal mining operations based on the risk factors. To do so, in a case study of Tabas Mechanized Coal Mine, the Failure of shearer data and the stoppages caused by it (for 2 years and a half, from March 2017 to June 2019) were studied to analyze the system’s resilience. Then, the experts were surveyed. After collecting and categorizing the data, the data analysis calculations were done for indicators of reliability, maintainability, supportability, organizational resilience, PHM system efficiency, and economic resilience. Finally, a new quantitative index named the “Shearer System Resilience Index” was introduced. The results indicated that resilience is reduced over time. They also shows that in order to improve resilience, project managers should pay more attention to these indicators, especially the indicators of maintainability, and organizational resilience. Therefore, regarding the scope of the data investigated in the current study, the use of Failure of Shearer data-based risk factors and experts’ opinions for the analysis of resilience in the case study is strongly recommended.

Coal mine roof accident causation modeling and system reliability research based on directed weighted network

Coal mine roof accidents have frequently caused massive casualties and economic losses. To understand the mechanism of roof accidents, 205 roof accidents in China from 2013 to 2022 were selected, and a total of 44 accident causal factors were identified, including the human-material-environment-supervisory and the final causal factor, and each causation chain was analyzed. Accordingly, a complex network is used to construct a causation network model for roof accidents, and the structural characteristics of the network are analyzed to obtain the key causal factors and important inter-causal relationships. Combined with the robustness analysis, three different intentional attacks are selected, and it is found that the proposed three methods significantly reduce the network efficiency compared with the random attack, and the deliberate attack based on the degree ranking has the best effect, which indicates that the developed method can effectively identify the causes of accidents. This study provides an important basis for the decision-making of coal mine roof accident prevention and reveals the difficulties of accident prevention, and also provides ideas and references for the study of accident mechanism and the construction of accident causation network model using complex networks.

Design and optimization of intelligent ventilation system in coal mine

With the continuous development of the coal industry, coal mine safety and environmental protection have gradually become the focus of important attention. The design and optimization of mine ventilation systems is a key factor in ensuring air quality and safety in the working area. In order to improve the application level of automation and intelligent equipment of mine ventilation system, under the existing conditions of mine, the design significance and goal of mine intelligent ventilation system are taken as the starting point, and the design and application effects are analyzed. By optimizing the layout of ventilation routes, increasing the number of sensors, building an intelligent ventilation system, optimizing the ventilation scheme in the main production scenarios such as coal face, driving face and opening up main roadway in the daily production process of the mine, realizing rapid wind regulation and wind counteraction when disasters occur, and using air flow short circuit to form protective measures, effectively avoiding the expansion of disasters and accidents. At the same time, remote automatic control of ventilation facilities and equipment is carried out to effectively improve the optimal utilization of air supply, avoid the phenomenon of insufficient air supply and waste of air volume, and improve the intelligent level of mine ventilation system.

Temperature and Humidity Monitoring and Communication System for Coal Mine Working based on LoRa

Temperature and Humidity Monitoring and Communication System for Coal Mine Working based on LoRa

Renovation of the retention bunker lining on the example of the Mysłowice-Wesoła coal mine

The scientific article focuses on the analysis, renovation and modernization of the retention bunker No. 4 at the 465 m level in the Mysłowice-Wesoła coal mine complex. This bunker, a key part of the mining infrastructure, has an important function in the coal mining process, accumulating output before its further transport to the surface. During a regular inspection of the bunker, significant damage was found in the form of defects on the lining, caused by the impacts of the output flow. Repair efforts required a comprehensive approach, including the use of rope access techniques (industrial mountaineering) for precise damage assessment and repair. The research and repair work included the installation of rappelling stations, rope access rappelling, non-destructive testing, bolting, concrete encasement of the damage, and other innovative repair techniques. Careful adaptation of operations to underground conditions and precise planning of logistics and repair work were key to successfully restoring the bunker’s stability and functionality. An analysis of the renovation process reveals the comprehensiveness of the measures, covering both the north and south sides of the bunker. The use of bolting, steel mesh, and innovative approaches allowed for the successful repair of damage. The ultimate success of the renovation helped minimize the risk of further damage and restore the integrity of the No. 4 retention bunker. The article also highlights the often-downplayed role of bunker in mining infrastructure, arguing that despite having ready-made longwalls and roadways, the absence of a functional bunker makes a coal mining system incomplete.

Classification and Design of Backfill Coal Mining Systems Based on Typical Engineering Cases

Backfill coal mining technology has drawn widespread attention due to its benefits of “controlling surface deformation and subsidence, reducing mining-induced disturbance in the stope, and recycling solid mine wastes”. However, the backfill coal mining technology is still progressing slowly in China. The geological environment of China’s mining areas is complex and highly diversified, and backfill coal mining is expected to fulfill different goals in a wide range of engineering scenarios. These facts explain the poor reproducibility of backfill coal mining projects. This study reviews the existing backfill coal mining systems in China. Based on findings from a survey of engineering cases, we summarize five types of new backfill coal mining methods classified by deployment style; namely, borehole grouting backfill, roadway backfill, borehole–roadway backfill, in situ backfill, and roadway-in-situ backfill. A total of 15 backfill coal mining methods falling into the above five categories are described. An engineering design workflow for backfill coal mining consisting of five steps is proposed; namely, identifying the targets of backfill, analyzing the feasibility of deploying the backfill system, comparing the engineering quantities of different engineering schemes, estimating the economic efficiency of backfill, and backfill performance tracking and monitoring. Real cases of backfill engineering design are analyzed to inform the fast and reasonable design of backfill strategy for specific working faces in certain coal mines.

Analysis of Acid Mine Drainage Formation Potential on Coal Stratification in Lamuru Area, Bone Regency, South Sulawesi Province

The open-pit mining system in coal mines causes the rocks at the mining site to be exposed to the surface so that water and air will react with rocks directly which will cause the formation of acid mine drainage, diverse morphological coditions with many springs and agricultural fields around the research area have an important role that must be maintained so as not to be polluted or damage agricultural land. The purpose of this study was to analyze the presence of sulfide minerals with sulfur content in coal stratification as the initial potential of acid mine drainage, in the lithology of the study area obtained seven lithological samples on coal stratification including overburden, S-01 (siltstone), S-02 (coal seam 1), S-03 (siltstone), S-04 (claystone), S-05 (coal seam 2), S-06 (sandstone) and S-07 (top soil). The results of the X-ray Diffraction (XRD) analysis detected the presence of pyrite minerals, with the results of the analysis of total sulfur ranging from 0.046 to 4.62%, and the results of the analysis of scanning electron microscope (SEM) obtained anhedral, subhedral and framboidal morphology This type of framboidal pyrite is a very fine crystal, very fast to react with air so that this pyrite is believed to be a trigger for the formation of acid mine drainage.

Analysis of drilling vibration characteristics of anchoring system in coal mine

A new type of parallel operation unit for excavating and supporting anchors is proposed to address the issue of imbalanced excavation anchor ratio in coal mines. By equipping a straddle type anchoring drilling rig group, the synchronous parallel and fast operation mode for excavating and supporting anchors is achieved; Consider the problem of poor drilling stability of drill pipes in coal mines due to the coupling vibration between surrounding rock and anchoring equipment. Firstly, taking the multi drilling rig anchoring system as the research object, considering the influence of the equipment itself as an influencing factor on the vibration of the drill pipe, a dynamic model of the system is constructed using Lagrangian equations, and analytical solutions for the vibration displacement of each mass block are obtained; In order to more intuitively represent the vibration process of the drill pipe, Ansys is used to conduct modal analysis on the key components of the anchoring drilling rig system, and obtain the natural frequencies and vibration modes of each order of the key components; Using Adams to solve the rigid flexible coupling dynamic model of the anchoring drilling rig system, the vibration response laws of the drill pipe under different operating states were obtained. Secondly, Abaqus was used to simulate the drilling process of the drill pipe and obtain the vibration response law generated by the interaction between the drill pipe and the surrounding rock; The results indicate that the anchoring equipment has a greater impact on the vibration of the drill pipe, and the surrounding rock has a more stable impact on the vibration of the drill pipe. Due to the short body and large span structure of the anchoring system crossbeam expansion frame, the vibration response of the drill pipe is significantly greater than that of the retracted state of the drilling rig due to being in an unstable cantilever state when the drilling rig is extended. The theoretical reliability of the vibration response law of the drill pipe under different states has been further verified through drilling experiments of the anchoring system prototype. The relevant theories can provide a theoretical basis for the implementation of automatic anchoring technology in the anchoring system.

Mineral extraction and long‐term human capital accumulation

AbstractThis study examines the long‐term impacts of early coal mining on human capital outcomes. Based on coal mines across 260 prefectures in late Qing China (c.1840–1912), we find that early coal mining led to a significant rise in schooling years in 2000. We trace the historical channels and show that the influence of early coal mining has persisted through and helped shape the modernization of China, which includes local industrialization and a complimentary supply of educational infrastructure. These results suggest that in contrast to other grabbing mineral extraction, inclusive coal mining systems benefit long‐term human capital accumulation and economic growth, not mining activity per se.

Positioning Control Strategy of Hydraulic Support Pushing System in Fully Mechanized Coal Face

At present, the hydraulic support pushing system in coal mines usually uses an electrohydraulic directional valve as the control component. However, the existing control methods based on high-speed on–off valve, servo, and proportional control methods are not suitable for solving such problems because of the nonideal characteristics of the electrohydraulic directional valve, such as discrete input values, low switching frequency, and time delay. This paper proposes a positioning control scheme based on online predictive feedback for the control of hydraulic cylinders by electrohydraulic directional valves. In this scheme, the recursive least-squares estimation algorithm with genetic factors is used to identify the required prediction model in real time, and an improved radial basis function network based on generalized growth and shear is used to realize the online fitting of the target trajectory function. The online learning algorithm provides accurate prediction information for the switching control method, and finally, the hydraulic cylinder can be positioned near the target position using the optimal control method. By using the above methods, a well-designed model can be accurately identified, fundamentally solving the problem of control difficulties caused by the nonideal characteristics of the electrohydraulic directional valve. Finally, the effectiveness of the control scheme is verified through simulation analysis and physical experiment research, which proves that the control strategy can realize accurate and fast positioning control for the hydraulic support pushing system of a fully mechanized mining face.

Rethinking the Operation Pattern for Anomaly Detection in Industrial Cyber–Physical Systems

Anomaly detection has been proven to be an efficient way to detect malicious behaviour and cyberattacks in industrial cyber–physical systems (ICPSs). However, most detection models are not entirely adapted to the real world as they require intensive computational resources and labelled data and lack interpretability. This study investigated the traffic behaviour of a real coal mine system and proposed improved features to describe its operation pattern. Based on these features, this work combined the basic deterministic finite automaton (DFA) and normal distribution (ND) models to build an unsupervised anomaly detection model, which uses a hierarchical structure to pursue interpretability. To demonstrate its capability, this model was evaluated on real traffic and seven simulated attack types and further compared with nine state-of-the-art works. The evaluation and comparison results show that the proposed method achieved a 99% F1-score and is efficient in detecting sophisticated attacks. Furthermore, it achieved an average 17% increase in precision and a 12% increase in F1-Score compared to previous works. These results confirm the advantages of the proposed method. The work further suggests that future works should investigate operation pattern features rather than pursuing complex algorithms.