Abstract：The development and utilization of spatial resources in closed mines is an important way and inevitable requirement to promote the transformation and development of old mining areas and the full life cycle development and utilization of coal mines.In order to further improve the efficiency of resource utilization in closed mines， this article takes Longdong Coal Mine as the background， analyzes the current situation of spatial resources in closed mines， and summarizes nine characteristics of mine closure and exit;An analysis was conducted on the shortcomings of the current utilization mode of closure and exit mine resources， with a focus on three aspects： "whether it can be utilized， how to utilize it， and key points of utilization". A development strategy of "overall planning， phased implementation， early start， and rolling development" was proposed， and a "one core， two wings， and multiple points" three-dimensional development and utilization mode of spatial resources in the closure and exit mine was constructed. The research results can provide reference for the research and practice of the development and utilization of spatial resources in closure and exit mines in China.

Caojiatan Coal Mine produces a large amount of coal gangue solid waste in the mining process, and the ground accumulation will cause problems such as waste of land resources and environmental pollution. The comprehensive utilization of coal gangue resources has certain limitations and the utilization rate is not high. To solve the problem, a set of large-scale grouting and filling processes for coal gangue was designed in this paper, and the field application was carried out. The system processed the "more crushing and less grinding" ground crushing and pulping scheme of "three-stage crushing + ball milling", and injected the coal gangue slurry into the falling zone of the underground goaf through the adjacent grouting and filling process, which realized the harmless and large-scale treatment of coal gangue. The process flow of the system included the crushing, pulping, pumping, and pipeline transportation of coal gangue to ensure the quality of the slurry and the efficient operation of the system. The industrial application showed that the diffusion effect of the slurry was good, the accumulation height and diffusion radius met the expectations, which effectively reduced the environmental pollution in the mining area, reduced the cost of coal gangue transportation, and realized the large-scale disposal of coal gangue. In the later stage, the grouting and filling process will be continuously optimized, so as to improve the utilization rate of underground fillable space and improve the large-scale grouting and filling capacity, so as to provide reference for the grouting and filling technology of coal gangue underground.

Taking the strip filling working face of No.3 coal seam in Shanxi Sanyuan Coal Industry as the engineering background, firstly, based on the clamped beam theory model, the deformation and stress characteristics of the branch roadway roof in strip filling mining are analyzed. Secondly, the numerical simulation method is used to reveal the interaction between the branch roadways and the distribution characteristics of the plastic zone of the branch roadways. Based on the theoretical analysis results and the actual conditions of the filling working face of Sanyuan Coal Industry, the reasonable width of the branch roadway for multi-round cyclic interval strip filling mining is determined to be 5m. Finally, the rationality of the width of the branch roadway is verified by engineering practice, the safe mining of the overlying coal resources is realized, and the green and sustainable mining of Sanyuan Coal Industry is promoted.

Mine closure is a long time, extensive and policy-oriented administrative management process, which has been widely and highly concerned in the world. This paper draws on the mine closure practice of foreign countries and regions with developed economy or mining industry and some institutions, and combines the current situation of mine closure mechanism, types of open-pit mine closure，mine closure management and technical problems faced in China. Based on national laws and regulations, this paper puts forward thoughts and suggestions on the financial guarantee mechanism for open pit closure, the reform of land use mode for open pit mining, the implementation of open pit closure mechanism throughout the life cycle of open pit and the strengthening of capacity building for open pit closure, which will help improve the open pit closure mechanism in China and have great significance for the reputation of enterprises and the sustainable development of society

Abastracts: Steel headframes are widely used in vertical lifting in large and medium-sized coal mines due to the excellent structural performance. The paper ,which bases on an actual project, expounds the key points such as model selection, force analysis, load combinations of four columns steel headframe design. Partial factors in different standards are used to calculate in the same model, and the different results are compared. The results indicate that design following the new standard is safer ,it can be used as a reference in similar projects. Meanwhile, the paper proposes the importance of preliminary plan and ideas of parameterized and modular design.

Stability control of the surrounding rock in deep gob-side entry under strong mining disturbance is a technical challenge. In order to study the evolution characteristics of the displacement and stress field in deep gob-side entry under dynamic load, the numerical model was established based on 103 working face of Gaojiabao coal mine. Then, the displacement and stress field evolution characteristics in deep gob-side entry under dynamic load were analyzed by FLAC3D software. Finally, the sensitivity analysis of the roadway response parameters was carried out by the machine learning method. The results show that: (1) according to the importance score, the roadway surrounding rock has the most obvious response to the dynamic loading amplitude under different dynamic loading factors; (2) under different dynamic loading amplitudes, the maximum deformation rate of the roadway reaches 17.5 mm/MPa, the maximum deformation rate of the two sides reaches 16.1 mm/MPa, and the maximum rate of plasticity development reaches 3,552.5 m2/MPa. (3) using regression analysis method, the empirical equations under different dynamic loading conditions are obtained. On this basis, the cooperative control technology of "letting pressure-supporting" is proposed to alleviate the deformation of the surrounding rock of gob-side entry. The results of numerical simulation and field monitoring verify the feasibility of the cooperative control technology.

In addressing the technical challenges associated with loose and weak surrounding rock in the 9# coal seam of the Luling Coal Mine, an analysis of the key factors affecting efficient excavation support and the optimization of critical support procedures was conducted. The objective was to achieve comprehensive control over the floor, roof, and sidewalls of the coal roadway in the context of loose and weak surrounding rock. The adopted approach involved utilizing the FLAC3D numerical simulation software to simulate the excavation support scheme and efficient excavation process in the II946 air roadway of the Luling Coal Mine.The designed measures for controlling the stability of loose and weak coal roadway surrounding rock involved the application of the "grouting anchor rod (anchor cable beam) proactive support + coordinated flexible support" technology. Field experiments demonstrated that the daily excavation dimensions in the II946 air roadway increased from 2.4m to 3.0-3.6m, effectively managing the deformation of loose and weak surrounding rock and consequently enhancing excavation efficiency.

In the process of underground coal mining, sometimes the original roadway section size cannot meet the normal production and needs to be expanded. Aiming at the problems of reducing the stability of roadway surrounding rock, expanding construction technology and supporting design, taking the occurrenc

e of belt conveyor roadway and the existing supporting conditions in the north wing panel of 5-2 coal seam in Huixing Coal Mine as the background, the safety and stability of surrounding rock and the limit span of roof are studied by combining theoretical analysis with numerical simulation, and the feasibility of expanding the side and increasing the span of belt conveyor roadway in the north wing panel is demonstrated. The stress evolution law of surrounding rock, the development characteristics of plastic zone and the safety and stability of roadway coal pillar before and after expansion are compared and analyzed. Combined with the limit self-stable equilibrium arch theory of roadway support, it is concluded that the failure depth of the two sides before and after the expansion of the belt conveyor roadway in the north wing panel is basically unchanged, and the roof failure height and the limit equilibrium arch height after the expansion are increased by 13.1% and 10.9% respectively. On this basis, the support parameters of the expansion section are determined, and the expansion construction technology of 'reinforcing the anchor cable in the roof before the expansion, supporting the new excavation roof and the expansion side in time during the expansion ' is proposed. Finally, the expansion construction and support field application research were carried out. The results show that there is no obvious crack in the surrounding rock of the expansion section, and there is no obvious spalling and moving deformation on the surface of the surrounding rock, and the overall safety and stability of the roadway.

The prevention and control of rock burst risk in coal roadway excavation work face is directly related to the safety production level of coal mines. The research aims to establish a graded management system for rock burst risk in excavation work face, and improve the effectiveness of rock burst prevention and control from the management level. In order to obtain a more reasonable hierarchical management system, factor analysis method is adopted. Firstly, the influencing factors of rock burst in coal roadway excavation working face are analyzed, and the main risk sources of rock burst in excavation working face are obtained. On the basis of risk factor analysis, the risk verification method is used to determine the use of two primary indicators and seven secondary indicators to comprehensively evaluate and classify the risk of rock burst in coal roadway excavation working face. Among them, two primary indicators are the theoretical and technical indicators of coal roadway excavation face anti-collision, and the personnel and management indicators of coal roadway excavation face anti-collision. Corresponding secondary indicators have been proposed for the primary indicators. The Analytic Hierarchy Process (AHP) was used to calculate the weights of various indicators, forming a risk classification system for rock burst in coal roadway excavation working faces. The classification results were divided into five levels: "safe", "relatively safe", "moderate", "relatively serious", and "serious". Based on different risk levels, a rational management system was proposed accordingly. Finally, the grading system was applied to the excavation face of Jinzhuang mine, which was initially rated as "relatively serious". After the development and implementation of targeted prevention and control safety measures and supporting institutional measures, the hazard level was raised to "relatively safe", indicating that the established grading management system is reasonable. The research results have certain reference significance for the prevention and control of rock burst in excavation faces.

In order to improve the recovery rate of top coal in the 0291 fully mechanized top coal caving face of Tangshan Coal Mine, the amount of top coal loss in the production process was theoretically calculated from seven aspects, namely, end loss, inter frame loss, and initial mining loss, using inter step loss as an optimization object, PFC2D software is selected to optimize the coal drawing step distance. According to the principle of "stopping when there is waste", the top coal drawing amount of different coal drawing steps is compared. The simulation results show that the top coal drawing amount exhibits significant fluctuations with the passage of the support. The step distance coal drawing amount of "one?cut?one?falling" is between 80-560 blocks, the step distance coal drawing amount of "two cut?one?falling" is between 50-680 blocks, and the step distance coal drawing amount of "three cut?one?falling" is between 100-1100 blocks, From the perspective of total coal discharge，the highest efficiency of coal discharge is "one?cut?one?falling", with a top coal discharge amount of 3832 pieces. Therefore, when the coal discharge step is optimized to "one?cut?one?falling", the loss between coal discharge steps can be effectively reduced.

Based on the problem of gas overlimit in high gas mines, the overlying rock fissure zone unpressurized gas extraction is not effective. Taking the 11210 working face of Xinzheng Coal Power Co., Ltd. as the engineering background, the physical similarity simulation method is used to study the development characteristics of mining fracture zone of overlying rock in coal seam group superimposed mining, reveal the evolution characteristics of mining fracture of overlying rock in coal seam group superimposed mining, and determine the optimal horizon of gas extraction through field verification. The results show that: during the process of coal seam group superposition mining, a large stress concentration was formed outside the pressure unloading area, and within the pressure unloading protection range, the stress concentration phenomenon was not obvious, and the peak stress was smaller than the original stress of the Er1 coal seam; the coal seam group superposition mining caused the superposition unloading of the rock layers overlying the mining field, which resulted in superpositional changes of the displacement field of the overlying rock layers, and the maximum subsidence of the rock layers increased further; after the end of the coal seam group superposition mining, the rock overlying the mining area was subject to a superpositional change, and the maximum subsidence of the rock layer increased further. After the end of the stacked mining of the coal seam group, the rock layer in the middle of the overlying rock layer in the mining area was compacted, and the rock layer fissures at both ends were more developed, forming a certain range of fissure development area. Reasonable layer selection for drilling holes in the rift zone was determined through field tests, and the results of physical similarity simulation were verified through on-site monitoring of the drilling holes.

In the prevention and control of coal gas disaster, it is of great significance to judge whether the gas prevention and control measures are effective to grasp the occurrence law of coal seam gas accurately. In view of the influence of different sampling techniques on the determination of gas content in coal seams, comparative investigation tests were carried out in No. 6 and 7 coal seams of Bailing Coal mine to analyze the best sampling methods in the sampling process of bedding drilling and cross-bedding drilling, so as to ensure the effectiveness of coal samples taken and further improve the reliability of gas content determination. In the sampling process of bedding drilling, the fixed-point sampling method of deep hole is obviously better than the sampling method of coal powder at the air discharge hole. The maximum out-of-tolerance value of gas content determination is 1.3387m3/t, and the maximum error is 23.47%. And the sampling method of coal powder at the air discharge hole is easy to increase the probability of injury accidents. In the process of cross-layer drilling sampling, the deep-hole fixed-point sampling method is better than the air discharge slag hole sampling method with coal powder, and the gas content measurement error is controlled within 10%. Through laboratory coal sample scanning analysis, deep-hole fixed-point sampling method can ensure and screen effective coal particle size to a large extent, and reduce the amount of gas loss. In order to ensure the reliability of gas control, deep-hole fixed-point sampling method should be adopted for the sampling of bedding borehole, and the thickness of coal seam and particle size of coal powder should be fully considered for the sampling of bedding borehole, and the appropriate sampling method should be selected comprehensively.

Due to the compressive and prying actions of the roof and floor, preventing rock bursts in near vertical coal seams presents considerable challenges. This study focuses on the Wudong Coal Mine's southern mining area, investigating the blasting pressure relief methods for the roof and floor rock bodies in near-vertical coal seams. Using case studies, numerical simulations, and onsite validations, this research analyzed the effectiveness of deep-hole blasting measures during rock burst occurrences in near-vertical coal seams. Although deep-hole blasting reduces the dynamic loads caused by the compressive and prying actions of the roof and floor, it is less effective in weakening the nearby rock mass at the working face and reducing static loads. To address these shortcomings, this study introduces a combined deep and shallow hole blasting method that mitigates the dynamic loads from prying actions, effectively weakens the rock mass at the working face, and reduces the concentration of static loads. The techniques include alternating deep and shallow hole blasting and simultaneous deep and shallow hole blasting. Compared to single deep-hole blasting, both methods further reduce the peak horizontal stress in the surrounding rock of the roadway. The simultaneous deep and shallow hole blasting shows better rock burst prevention effects than alternating blasting but at a higher engineering cost. In the southern mining area of Wudong Coal Mine, alternating deep and shallow hole blasting has been applied. Microseismic monitoring results indicate that, compared to deep-hole blasting alone, the implementation of combined deep and shallow-hole blasting significantly reduced the occurrence of high-energy events (greater than 104J) from 9.3% to 0.2% and shifted the microseismic energy from "low-frequency high-energy" to "high-frequency low-energy," effectively mitigating the risk of rock bursts. These findings provide significant support for preventing rock bursts in near vertical coal seams.

Surrounding rock deformation control of gob-side entry is the technical difficulty of roadway control. The greater the thickness of coal seam mining and the higher the strength of overlying rock, the greater the difficulty of gob-side entry deformation control. Aiming at the problem of dynamic pressure control of gob-side entry in large mining height working face of Yushupo Coal Mine, the mechanical model of lateral hanging plate structure of gob-side entry is established. The theoretical analysis shows that the maximum lateral hanging roof length of main roof is 4.69 m, and the maximum strain energy density of main roof is located at 5.51 m in coal pillar, which is 2.831 × 106 J/m3, and the accumulated strain energy of main roof is 3.269 × 107J. By means of numerical simulation, the development of plastic zone, deformation law and stress distribution characteristics of surrounding rock in goaf roadway are further analyzed. It is found that the supporting stress of goaf coal pillar can reach more than 35 MPa, which is the main factor causing the large stress of bolt and cable in roadway coal pillar and the deformation and failure of coal pillar. The comprehensive technical means of “pressure relief hole + lateral roof cutting” is used to control the dynamic pressure roadway in the field. The diameter of the pressure relief hole is 108 mm and the depth of the hole is 7 m. The hydraulic fracturing hole is divided into L hole and S hole, the aperture is 60mm, the spacing is 8m, the vertical fracturing height is 50 m and 30 m respectively, and the water injection rate is 80 L/min. The field practice shows that compared with the section without pressure relief measures, the deformation of surrounding rock of roadway is reduced by more than 30%, and the floor heave of roadway is obviously controlled.

The hydraulic support system in China cannot accurately predict disasters such as roof, coal brust, coal and gas outbursts, and the prediction of periodic weighting during support in complex environments of fully mechanized mining faces has always been a major challenge for unmanned working faces. To address this issue, research has found that the ConvLSTM model with spatiotemporal correlation analysis and Point of Intersection (POI) data has been established through methods such as theoretical analysis, data collection and preprocessing, model evaluation and optimization. To obtain the optimal solution for periodic pressure prediction. Realize real-time perception and prediction of the working environment status. The experimental results show that the mean square error of the POI ConvLSTM model prediction of working face periodic weighting is 0.159, and the R2 evaluation index is 0.999. Compared with the Seq2Seq and ConvLSTM models, the mean square error is reduced by 68.07% and 4.22%, respectively. Therefore, the POI ConvLSTM model that integrates multiple data sources has higher prediction accuracy, stronger universality, and can accurately predict periodic pressure problems in advance.

Hydraulic fracturing top-cutting and pressure relief is the main means of pressure relief in coal mine roadways to release the roof pressure of the working face. This article theoretically analyzes the influence law of rock stratum cracking pressure during hydraulic fracturing process under different drilling parameters (azimuth angle, inclination angle) and different type of 3D stress. Based on the study 3D stress of rock stratum after mining, the hydraulic fracturing opportunity of 3310 haulage gate of the Wangpo Mine is confirmed as well as the principle of bore hole layout. The stress monitoring results show that the new fracturing scheme reduces the average peak stress by 52.9% compared to the conventional fracturing scheme. The deformation monitoring of the surrounding rock in the roadway shows that compared with the original fracturing scheme, the new fracturing scheme reduces the subsidence of the roof by 14.0%, the bottom bulge by 37.8%, and the displacement of the two sides by 56.6%. The surrounding rock of the 3308 transportation channel has been well protected.

The stress and strain along the rod body was complicated under special shape and multiple types of loads, which played an important role in its long-term stability in service. The stress and strain characteristics and evolution rules of normal and defective rebar rockbolts under different working conditions were analyzed by numerical simulation based on laboratory tensile testing and DIC monitoring, in view of the complex and varied stress and strain of rockbolt and the difficulty of accurate measurement. The main conclusions were as follows: The maximum stress, maximum true strain and maximum plastic strain of rockbolt increased gradually with the increase of load value and type. When the rockbolt had defects, the stress and strain at the defect site were obviously concentrated, while the shape and location of defects affected the stress and strain distribution rules. Due to the existence of thread, transverse rib structure and defects, local stress and strain concentration generated in the rod body of rockbolt and the plastic strain was also larger. The sites of plastic strain concentration were prone to develop into the source of cracks under the influences of high load and corrosion, and then lead to the failure of rockbolt. The relevant conclusions can provide reference for structure optimization, condition monitoring and life prediction of rockbolt.

Abstract：In order to investigate the distribution law of ground stress in shallow coal seam in Jixi mining area, the hydraulic fracturing method is used to carry out ground stress testing at 30 measuring points in 5 representative mines, and the measured results are analyzed deeply. The results show that the vertical principal stress is smaller than the maximum horizontal principal stress, the horizontal stress occupies the main part of the stress, and the tectonic stress field is prominent. There is no ultra-high stress field, but low, medium and high stress field are distributed, mainly low and medium stress field. The maximum horizontal principal stress direction of six Wells in Lushan Coal Mine and droplet clean coal mining area No. 9 is concentrated in NE; The maximum horizontal principal stress direction of Donghai Coal Mine and Erdaohezi Coal mine is concentrated in NW; The direction of the maximum horizontal principal stress at 3 measuring points is concentrated in NE, and the direction of the maximum horizontal principal stress at 6 measuring points is concentrated in NW. The horizontal principal stress is positively correlated with the buried depth in general, and the correlation between the minimum horizontal principal stress and the buried depth is worse than that of the maximum horizontal principal stress. The side pressure ratio was in the range of 1.16-5.28 and all exceeded 1. With the increase of buried depth, the side pressure ratio gradually decreased, but the dispersion was strengthened. With the increase of buried depth, the relative difference of maximum and minimum principal stress tends to increase, and the horizontal principal stress difference ratio gradually approaches 0.5. The horizontal principal stress difference of different mining levels is larger. The research results have important guiding significance for mining engineering design and surrounding rock control of shallow coal seam in Jixi mining area.

Water content has an important influence on the mechanical properties of coal. In order to further explore the mechanism of water content in coal mechanics under triaxial loading conditions, representative coal samples in Pingdingshan mining area were selected and experimental groups with different water content levels were set up. Uniaxial compression tests of coal samples with different water contents and triaxial compression tests of coal samples with different confining pressures were carried out, and comprehensive performance tests of stress-strain relationship and compressive strength of coal samples with different water contents were carried out. The results show that under different confining pressure conditions, the stress-strain curve of water-bearing coal shows the same trend. Under the condition of triaxial loading, the stress-strain curve in the axial direction of water-bearing coal body is the same as that in the axial direction of coal body under uniaxial loading. Under the same water content condition, the axial strain of the test coal samples with different confining pressures is slightly different when the stress peak appears. The larger the confining pressure, the smaller the axial strain corresponding to the stress peak. During the whole loading process, the axial strain of the test coal sample is always positive, that is, the axial compression deformation of the coal body occurs in the axial direction, and at the same time, the radial expansion deformation of the test coal sample occurs. Under uniaxial / triaxial loading conditions, with the increase of water content, the peak strength decreases as a whole, and the relationship between water content and peak strength is a quadratic function. With the increase of confining pressure, the peak strength is as a whole.

To enable the coal mine equipment detection platform to accurately and rapidly identify critical components of complex mining equipment, a lightweight improved model named Ghost-YOLOv4 based on YOLOv4 is proposed. This model introduces GhostNet as the backbone of YOLOv4's CSPdarknet-53, which not only reduces the number of model parameters and redundant computations but also shortens the model training time. The shortcut structure in GhostNet mitigates network degradation and enhances the model's feature extraction capability. Experimental results demonstrate that the number of parameters in GhostNet is reduced by 83% compared to YOLOv4 and by 6% compared to MobileNetv3-YOLOv4, with an average recognition accuracy of 92.51%. The image detection speed (FPS) can reach 33.75 frames per second, representing a 43% improvement over YOLOv4. Ghost-YOLOv4 effectively addresses the issues of slow detection speed and large model size in the task of detecting critical components of complex mining equipment.

In order to determine the normal, tangential, critical stress and other parameters of the bilinear wire rope cohesion model, this paper proposes a method based on the construction and verification of the wire rope cohesion model. Firstly, the theoretical model of cohesion is established to analyze the relationship be-tween the tensile bond strength and the displacement in the direction and the tangential direction. Then the normal and tangential tensile bonding strength test samples were prepared by a small vulcanization device, and the parameters were measured by a universal tensile testing machine. Finally, based on the bilinear cohesive model parameter values extracted from the experimental results, the finite element simulation software ABAQUS is used to simulate and verify the experimental process. The experimental results show that the maximum error between the simulation results and the experimental results is about 2.7 %. Ac-curate determination of the required cohesion parameters of the wire rope-rubber bonding interface is suitable for describing the adhesion and failure of the steel-rubber interface.

Wire rope is a key component used by many industries such as mines, elevators, and cableways to pull, lift, transport, and carry equipment. During long-term operation, steel wire ropes may suffer from wire breakage, cross-sectional wear, rust and other damages, leading to unsafe hazards. Regular safety monitoring and evaluation of the health status of steel wire ropes is crucial. This study proposes a new method for identifying steel wire rope damage based on the spatial magnetic field balance mechanism to address the shortcomings of traditional strong magnetic detection methods. Firstly, the three-dimensional solid modeling using PRO/E was studied, and the magnetic circuit design was carried out, and secondly, the finite element analysis was used to compare the advantages and disadvantages of the X-axis and Y-axis magnetization directions, and the Y-axis magnetization direction was better than the X-axis magnetization direction according to the magnetic field line density and the change strength of the intermediate linear magnetic field. Finally, by using the three-dimensional magnetic field numerical analysis software, the appropriate sensor concentrating ring structure and sensing unit are designed and calculated. The results show that the wire rope flaw detection sensor based on electromagnetic field balance detection is better than that of the strong magnetic detection sensor.

Abstract：In underground mining environment, surveillance images are subject to fogging degradation because of dust scattering and it is difficult to conduct environmentally controlled experiments in situ for fogging and defogging investigation. Therefore, this paper defines the degree of image fogging by using the relative average gradient, analyzes the composition of the dust particle sizes in the mine, proposes the method for compose experiment powder to simulate different mining dust, and designs and builds a simulation air chamber to simulate the mining scattering environment. The results indicate that: 1. The degree of fogging defined by the average gradient is better than other commonly used evaluation parameters and its evaluation results are consistent with the human eye perception. The degree of fogging of underground mining images can reach 80%, when the image details merge in the foggy blurring effect. 2. With microscopic observation method we found that 99% of underground mining dust has particle size less than 30 and the proportion with the particle size less than 10 is about 93%. 3. The foggy image generated from the simulated air chamber not only covers the range of the image fogging degree of real mining surveillance images, but also shows the diffusion effect of light scattering, consistent with real surveillance images, that was not produced by the computer-based fogging algorithm, proving the advantage of the air chamber method. This article provides an experimental basis for the study of underground image dehazing method.

To study the influence mechanism of oxygen-containing functional groups on the surface potential of coal, the Zeta potential of three kinds of demineralized coal with different oxygen-containing functional groups was measured. Combined with molecular dynamics simulation and density functional theory calculation, the charging mechanism of coal surface was revealed. Studies have shown that the surface potential of coal is related to the number of oxygen-containing functional groups on its surface. The more abundant the oxygen-containing functional groups on the surface of coal, the more negative the surface potential. The surface charge of coal is the result of OH-preferential adsorption. OH-promotes the dissociation of O-H structure in carboxyl and hydroxyl groups on the surface of coal, so that the surface of coal is finally negatively charged. With the increase of coal metamorphism, the content of -COOH group and -OH group in coal shows a downward trend. Therefore, the absolute value of potential of long flame coal, coking coal and anthracite also decreases in turn, which eventually leads to the difference of electrostatic force between particles and bubbles

Abnormal material loading on the vibrating screen is a common issue in industrial production, with repercussions that extend beyond production efficiency to include potential safety hazards. Therefore, monitoring material status on the screen in real-time and with precision holds immense importance. However, the traditional monitoring method primarily relies on manual on-site observation, which is labor-intensive, slow, fraught with significant safety risks, and often inadequate for identifying minor equipment faults. This approach falls short of the demands for material status monitoring on the screen. This paper introduces a dynamic material status monitoring method for vibrating screens that utilizes a Time-of-Flight (TOF) camera. This method combines a point cloud data completion approach with a KD tree within the frame difference method, alongside a dynamic monitoring technique based on surface reconstruction. These methodologies enable the real-time monitoring of material status on the screen. The point cloud data completion method, coupled with the KD tree within the frame difference process, effectively addresses the challenge of missing point cloud data caused by moisture on the material's surface and gaps between materials during TOF camera capture. Through the analysis of the reconstructed point cloud surface of the completed screen materials, it becomes possible to determine the status of four material conditions on the screen: underload, overload, left bias load, and right bias load, thus enabling real-time material detection on the screen. This study acquires material state information on the screen directly via the TOF camera, reducing the need for manual intervention and providing real-time performance. Consequently, it offers a highly efficient and dependable solution for real-time monitoring of material conditions on the screen.

Through the endless-rope winch and rope towed rail Shuttle car brake，the marshalling of form，as well as the provisions of the relevant specifications, standards, codes, explore endless-rope winch and rope towed rail in inclined lane transportation system the question of whether or not to need to set up protective device to avoid fast-run-ning cars, is presented based on the analysis of the device setting principles and recommendations.

Aiming at routine inspection and parameter determination in the complex environment of a coal mine, an intelligent inspection robot system for the coal mine transportation system is proposed. The control system consists of a robot body, base station, automatic charging device, track system, cleaning device, and ground workstation. The field test proves that the system can complete the intelligent inspection of modern equipment in coal mines accurately and efficiently, reduce the operating cost of coal mine enterprises, improve the production efficiency of enterprises, and ensure the safe operation of coal mines.