Since the implementation of the 14th Five-Year Plan, Xinjiang's coal production and external transportation volume have seen significant growth, rapidly increasing their proportion in the national total. Xinjiang has actively integrated into the unified and open national market, playing a vital role in ensuring a stable coal supply nationwide. This paper briefly discusses Xinjiang's coal resource endowment, current status of coal production and development, overall situation of "Xinjiang coal external transportation," and railway transportation pattern. Based on the approved overall planning of coal mining areas in Xinjiang, the analysis indicates that Xinjiang's coal resource development potential is immense. On this basis, combined with the national coal production and development layout, as well as domestic demand in Xinjiang, the trend of Xinjiang's coal production and development is assessed. Further analysis shows that with the enhancement of Xinjiang coal external transportation channel capacity and the increase in major market demand for Xinjiang coal, the volume of Xinjiang coal external transportation is expected to see a significant increase, increasingly integrating into the unified national market.

In order to improve the stability and safety of roadway in mining engineering, after nearly 60 years of research and continuous optimization at home and abroad, the theory and practice of lining roadway and surrounding rock control have accumulated rich achievements. This paper deeply analyzes the application of lining roadway in different mining modes, such as forward, regressive and reciprocating mining. At the same time, it elaborates on the five key surrounding rock control technologies of lining roadway, namely surface support, anchorage, modification, pressure relief and joint control. On this basis, the paper further discusses the application scenarios of filling and top-cutting lining roadway. In particular, in the practice of filling lining roadway, by comparing with other filling materials and methods, the unique properties of high water material and their application characteristics in the filling process are deeply analyzed. Experiments and field data fully prove that the filling technology of high water material can effectively strengthen the structural strength of roadway, significantly reduce the risk of safety accidents, and significantly improve the recovery rate of coal resources. In addition, this paper also studies the construction technology of this technology, including the key elements of material proportioning and filling methods. The research provides important guidance for the practice of mining engineering, and lays a foundation for the further development of this technology.

The vertical shaft skip hoisting system serves as the critical hub for coal mine main transportation. Addressing the characteristic requirement of frequent speed variations in quantitative belt conveyors, this study proposes kinematic calculations to achieve precise control. A trapezoidal acceleration curve control strategy is adopted for speed transition processes. By establishing a kinematic model of the quantitative belt conveyor, this paper systematically analyzes its motion characteristics during low-speed loading phase, high-speed unloading phase, and speed transition phase. The computational formulas for travel distance and time in each operational stage are derived. Through engineering case verification, temporal sequence matching schemes under different feeding positions are validated, providing theoretical foundation for automated collaborative control and optimized design of main shaft hoisting systems in coal mines.

Abstract: This study addresses the challenges of complex and high-risk underground coal mine environments, difficulties in personnel health monitoring, and the limitations of single monitoring methods. It proposes a multi-dimensional status monitoring and real-time risk prediction system based on smart wristbands, portable monitors, and smart information-capable miner's lamps. The system collects real-time physiological parameters (e.g., heart rate, body temperature, blood oxygen saturation) and environmental parameters (e.g., methane, carbon monoxide concentrations) from underground personnel. Data is transmitted to a surface server via the mine IoT (Internet of Things) system, establishing a unified monitoring platform.For data processing, the study innovatively establishes a fatigue assessment model based on a Backpropagation Neural Network (BPNN). This model achieves precise estimation of miners' fatigue levels by analyzing the correlation between physiological parameters and perspiration pH value. Furthermore, by Conditional Score-based Diffusion Models (CSDI), the system fuses multi-dimensional data (physiological, environmental, and personnel location) to enable dynamic risk prediction and proactive health assessment.Experimental results demonstrate that the system achieves a fatigue assessment error not exceeding 0.05 and a prediction accuracy rate of 95% or higher, significantly enhancing operational safety and health management for mine personnel. This research provides an intelligent solution for coal mine safety production, holding substantial theoretical value and practical significance.

Abstract：To address the structural instability issue of corrugated steel pipe culverts in open-pit mines caused by asymmetric backfilling under heavy-duty transportation environments, a modular rehabilitation technology utilizing an I-Beam framework is proposed, Adopting a hybrid methodology integrating numerical simulation and field measurements and developing a three-dimensional finite element mode by Midas GTS NX to investigate of progressive deformation behavior in corrugated steel pipe culverts under asymmetric backfill conditions. A modular I-Beam reinforcement design was developed based on structural damage characteristics. Rapid rehabilitation of damaged zones was achieved by integrating standardized component prefabrication, progressive installation techniques, and a mechanism of load transfer synergy between new and existing structures, which was validated through static load testing and finite element model calibration. The results indicate: 1) Asymmetric backfilling caused lateral displacement of 321.6 mm and a peak arch-foot stress of 359 MPa, leading to local buckling instability; 2) After reinforcement with the I-steel frame, the vertical displacement of the arch crown (23.8 mm) and circumferential stress at the arch foot (247 MPa) were restored to the original design levels (24.5 mm, 255 MPa), and the maximum displacement under dynamic loads met the L/300 limit requirement; 3) The relative displacement error between numerical simulation and static load tests was 3.5%, verifying the reliability of the model. As a result, I-Beam framework reinforcement technology enables effective restoration of the load-bearing capacity in damaged culvert structures. The I-steel frame reinforcement technology effectively restores the bearing capacity of damaged structures through rigid support network reconstruction and optimized stress redistribution, providing an efficient solution for repairing corrugated steel pipe culverts in dynamic heavy-duty environments of open-pit mines, with significant engineering promotional value. This technology offers a viable solution for rehabilitating corrugated steel pipe culverts in open-pit mines under heavy-haul transportation conditions, demonstrating significant practical engineering value.

Aiming at the problems of deformation and failure of surrounding rock and difficult support of semi-coal rock roadway along goaf in gently inclined coal seam in deep high ground stress environment. The deformation mechanism of surrounding rock of gob-side entry in semi-coal rock is discussed by means of theoretical analysis, numerical simulation and field test. The evolution characteristics of stress and displacement of surrounding rock under different support conditions are analyzed, and the field engineering practice is carried out. The results show that the bearing capacity of small coal pillar is the key to control the deformation of surrounding rock. The deformation of surrounding rock o n both sides of roadway under the original bolt and cable support is asymmetric. The coal seams on both sides are easy to slide and bulge along the weak surface of coal rock. The bearing capacity of small coal pillar is insufficient due to shear failure. As the key part of support, the internal stress of small coal pillar is increased by 45% and the deformation of surrounding rock is greatly reduced after support optimization and grouting modification and reinforcement of surrounding rock. The excessive stress difference between the two sides under the influence of mining is the main reason for the asymmetric deformation of roadway surrounding rock. Grouting modification and reinforcement can restore the strength of surrounding rock and improve the stress environment. Based on this, the surrounding rock control scheme of " high-strength prestressed anchor cable combined with grouting modification and reinforcement " is proposed. The field practice shows that the surrounding rock control effect of the roadway in the test section is remarkable. The research results can provide reference for the surrounding rock control of deep semi-coal rock gob-side roadway under similar geological conditions.

In the construction of large chambers and chamber groups in coal mines in the western region of China, there are common difficulties such as unclear deformation laws of surrounding rock in chambers and great difficulty in support, which has become one of the main factors restricting the safe construction of large chambers in coal mines. Based on the construction project of bottom loading chambers in the Hongqingliang Coal Mine in Ordos, a three-dimensional computational model of the chamber was established using FLAC^3D to simulate the stability and long-term stability of the chamber after one-time support excavation. It was found that the deformation of the surrounding rock is significant in the upper roof of the chamber and at the connection between the chamber and the inclined shaft; the thickness of the plastic zone in the two sides area is about 6 m, the thickness of the plastic zone in the roof is about 5 m, and the thickness of the plastic zone in the bottom is about 5.5 m. Strengthening of anchor support is required, with recommended anchor lengths of 7.5 to 8 m. Engineering measurements showed that after excavation and support of the chamber, the stress on the anchor rods and cables increased rapidly in the initial stage and gradually stabilized in the later stage. The stable deformation time of the internal anchor rods and cables in the chamber is approximately 20 days, and the stable zone of stress concentration at the connection between the chamber and the inclined shaft is approximately 15 days. The measured stress on the anchor rods and cables is less than the breaking load, indicating that the overall support structure of the chamber is stable and safe. The research results will provide data reference and theoretical support for the construction of similar large chambers in soft rock formations in the western region.

Burnt rock is characterized by structural fragmentation, well-developed fractures, and strong water-rich properties, making it a key challenge for surrounding rock control in shallow-buried coal seam roadways in western China. Based on the actual engineering conditions of the burnt rock zone exposed in the No. 11 coal seam at the +1710 return airway of Yushuling Coal Mine, a fracture density-based zoning system for surrounding rock was established through field measurements and numerical simulation. The disaster evolution mechanism was identified, and a targeted zoning control strategy and optimized support scheme were proposed. The study shows that the fracture density of burnt rock can be divided into three categories: intact zone, fractured zone, and severely broken zone. Corresponding support systems are designed with cable bolt densification, grouting reinforcement, and combined steel-set support as the core measures, forming an integrated "support–reinforcement–protection" control model. This technical system effectively enhances surrounding rock stability, controls deformation, and ensures excavation safety, providing valuable guidance for the control of similarly weak and fractured rock roadways.

In order to provide design basis for surrounding rock support of rock burst roadway in Binchang mining area, support materials and components commonly used in roadway support system were selected to carry out static load and impact dynamic load test research. The static mechanical properties of anchor cables, bolts, trays and metal meshes, as well as the mechanical response characteristics and failure modes under the action of impact dynamic load are systematically analyzed. The experimental results show that: under the action of static load, the ultimate bearing capacity of the bolt is 293.7 kN, and the elongation rate is 12.5%. The tensile strength of the anchor cable reaches 1980 MPa, and the elongation rate is 9.9%. The compression load-deformation curve of the bolt tray develops in multiple stages, and the maximum load is 386 kN. Under the action of drop hammer impact, the impact force-displacement curve of the bolt goes through three stages: the elastic stage, the plastic stage and the rebound stage. The bolt can withstand a maximum of 8 impacts, with an impact elongation rate of 9.98%, and its brittleness is enhanced. The impact force-displacement curve of the anchor cable develops in four stages: tightening, rapid growth, stable deformation and rebound. The maximum peak value of the impact force is 550 kN, the elongation rate under dynamic load is 1.57%, and the absorbed energy is 1.35×104J. The impact force-displacement curves of the bolt tray and the W-shaped tray successively go through four stages: slow growth, linear growth, steady growth and sharp decay. Compared with the bolt tray, the W-shaped bolt has a large deformation and a small impact force in the slow growth stage, and its impact resistance in the early stage is poor. The impact force-displacement curve of the metal mesh roughly goes through three stages: linear growth, violent fluctuation and rapid decay. With the increase of the impact energy, the peak value of the impact force basically shows an increasing trend, the deformation continues to increase, the mesh basically maintains its original shape, and it has good cushioning performance.

Under multi-seam geological conditions, the underlying working face is more prone to frequent and severe roof disasters. Revealing the failure mechanism induced by overlying goafs and residual coal pillars is crucial for ensuring roof stability and safe mining in the underlying seam. Taking the 32302 working face of Chahasu Coal Mine as the research object, this study integrates theoretical analysis, numerical simulation, and field monitoring to systematically investigate the mechanism of abnormal roof weighting. A stress zoning model for the floor under residual pillar influence is established, identifying a shallow shear-compression stress concentration zone and an abnormal stress distribution range of ±50?m. An elastic thin-plate model of periodic weighting is developed, indicating that initial instability occurs after 11.4?m of face advance and becomes significant at 15?m. Based on FLAC3D three-dimensional simulation and field hydraulic support resistance data, the study reveals stress superposition characteristics and transfer paths caused by overlying goaf edges and residual pillars. The peak advance stress increases up to 34.08%, with concentrated stress reaching 24.23?MPa. Accordingly, a three-zone classification criterion based on face advance distance is proposed: a 50?m warning zone ahead of the gate, a ±20?m high-risk zone near the gate, and a 20?m stress-relief zone behind the gate. The results provide theoretical support and engineering guidance for the identification and prevention of roof hazards under similar geological conditions.

Huainan coalfield has a very thick loose layer deposited on the bedrock. The fourth aquifer at the bottom (hereinafter referred to as "the fourth aquifer") is thick and rich in water. The direct water filling source of the roof of No. 5 coal seam in Banji coal mine is recharged vertically and laterally by the fourth aquifer. The mine is facing a serious threat of water damage in the loose layer of the roof and the risk of shaft deformation and damage caused by the settlement of the water loss stratum of the fourth aquifer. It is necessary to ensure that the loose layer has "zero water"; In order to solve the above water disaster problems, based on directional drilling and long-distance grouting technology, the advanced regional governance scheme of roof water disaster is proposed, which changes the thinking of water disaster prevention from passive governance to active prevention, that is, before the mining of the working face, the vertical guiding water level is transformed by grouting above the roof water guiding fracture zone, and the lateral supply channel is curtain closed; The reliability of the treatment layer is demonstrated by numerical simulation and similar material simulation, and the flexible quantitative index is established. The ratio of flexible cement clay slurry is optimized through slurry ratio test, which further reduces the possibility of failure of the grouting layer of the roof after mining; At the same time, the high-pressure slurry diffusion control grouting technology in the non bottom partition area under the adjacent loose layer is formulated; The engineering practice results show that: the advanced treatment technology of roof water damage area effectively cuts off the vertical and lateral supply of the roof before mining, and the roof treatment layer is not damaged by mining during mining, realizing the goal of "zero water" in the loose layer after mining in the working face. The research results have certain significance for preventing and controlling the roof water damage under the extremely thick loose aquifer and enriching the mine water control technology.

Abstract：Aiming at the problem that the existing method of determining the hole spacing of gas extraction technology only relies on the simulation of gas transportation in the airspace area and field experience, lacks systematic and comprehensive analysis under the condition of multi-field coupling, and fails to fully consider other disaster-causing risk factors in addition to gas, this study takes the working face of 2-105 as the experimental area, and carries out the research by combining the simulation with the actual test method. Firstly, we simulated the gas transportation law in the mining area under different drilling distances to determine the basic interval of hole spacing; on this basis, we coupled the analysis of the temperature field, oxygen concentration field and wind speed field in the mining area to optimize the hole spacing; finally, we verified the simulation results through on-site measurements. The study shows that the hole spacing based on the gas field simulation is 25m, while the multi-field coupling analysis shows that increasing the spacing will lead to the enhancement of air leakage and the increase of oxygen concentration, which will lead to the expansion of spontaneous combustion zone and the migration of the high temperature zone, and therefore, the 20m dynamic extraction strategy is proposed. On-site measurements show that the gas concentration in the upper corner is lower than 0.8% in the interval of 15-35m between the drill holes and the working face, the maximum difference in oxygen concentration is 0.9%, and the maximum difference in temperature is 0.8K, which is smaller than the simulation results, and verifies the accuracy of the simulation. This study improves the application system of the gas extraction technology under multi-field coupling conditions, and provides a scientific and accurate technical basis and decision-making reference for its optimization and the prevention and control of coal mine gas and fire disasters.

Taking the Pingdingshan mining area, a typical deep mining region, as the engineering background, the gas occurrence characteristics controlled by geological structures were elucidated. Based on the distribution features of coal and gas outburst incidents and the evolutionary causes of compound dynamic disasters, it was revealed that in-situ stress, geological structures, and coal seam thickness variation zones are the key factors in monitoring and early warning for compound dynamic disasters. Consequently, a monitoring and early warning system for such disasters, based on the spectral acoustic method, was introduced and applied to the driving faces of the Ji15-15080 machine roadway and return airway at the No. 8 Mine of Pingdingshan Tianan Coal Industry Co., Ltd. Test results indicate that: outburst risk indices exhibited abnormal variations and exceeded critical thresholds within a certain distance ahead of fault exposure, with exceedance locations distributed in coal thickness variation zones and dip angle change areas; The indexes of gas emission and sudden coal extrusion exceed the critical values in the fault-affected area and the change zone of coal thickness, indicating that this area is in danger of dynamic disasters. The monitoring and early warning outcomes are consistent with field conditions. The system provides a novel technical approach for early warning of compound dynamic disasters in deep mining.

To address the issue of drill pipe joint fractures leading to dropped drills, this paper analyzes the mechanism behind thread fractures and subsequent drill drops, proposing a synchronous double-thread anti-drop technology. The design incorporates a synchronous double-thread + connecting rod structure, where the main thread bears the load, and the secondary thread and connecting rod maintain axial connection to prevent tool detachment. The design concept of the synchronous double-thread pin and box joints is introduced, along with calculation methods for the main thread's load-bearing capacity and the anti-drop capability of the secondary thread and connecting rod. Performance tests were conducted on Φ89mm double-thread drill pipes, demonstrating a torsional resistance of 34904 N?m and a tensile resistance of 1878 kN—2.33 times and 6.26 times the rated capacity of the matching drill rig, respectively. Simulated secondary tensile resistance after pin and box thread fractures reached 517 kN and 433 kN, 1.72 times and 1.44 times the rig's rated pulling force, fully meeting safe drill retrieval requirements. The test results confirm that the synchronous double-thread structure effectively resolves the problem of drill drops caused by joint fractures, significantly enhancing drill pipe reliability and operational safety.

Currently, most intelligent photoelectric dry separators are designed for two-product separation, which lack flexibility when processing raw coal with high middlings content, leading to potential coal resource losses. To address this issue, the three-product intelligent dry separator, through multi-stage recognition and separation mechanism design, can simultaneously separate clean coal, middlings, and gangue. Existing research on three-product dry separators primarily focuses on mechanical structure optimization or image recognition algorithm improvements, while the impact of coal quality characteristics (such as particle size composition and density composition) on separation efficiency remains unclear. This study investigates and compares the coal quality characteristics and corresponding separation effects of two feed materials using the TDS32-300 three-product intelligent photoelectric dry separator. Experimental results show that the probable deviation of the photoelectric intelligent dry separator is significantly higher than that of dense medium separation equipment, and the E-value used for evaluating the performance of dense medium separation equipment is not suitable for assessing the separation performance of photoelectric intelligent dry separators. The properties of the feed material significantly affect the separation efficiency of the three-product dry separator. A higher content of large particle sizes improves separation efficiency, and a higher content of >70 mm particles is more conducive to separation. When the feed material contains a high proportion of intermediate density particles, the separation accuracy of middlings and clean coal by the three-product dry separator is significantly reduced. The findings of this study provide valuable insights for the refined separation and system upgrade of three-product intelligent photoelectric dry separators.

The floor heave of conventional gob-side entry retaining is more serious in the stage of primary mining and retaining.In order to optimize the stability of gob-side entry retaining with roof cutting and pressure relief in deep mine,this study focuses on the evolution law of floor heave in the whole life cycle and puts forward prevention and control strategies.Based on the 360606 working face of Xinji No.1 Coal Mine in Huainan,the theoretical analysis, mechanical modeling and FLAC3D numerical simulation are used to carry out the research.The theoretical analysis reveals the mechanism of floor heave in each stage.Due to the redistribution of stress in the excavation stage,the amount of floor heave is 118 mm.In the first mining stage,under the influence of abutment pressure,the amount of floor heave increases to 351.6 mm;in the second mining stage,the basic bottom is bent and unstable,and the amount of floor heave is 836.9 mm.The numerical simulation shows that the vertical stress peak reaches 44 MPa during the secondary mining,and the plastic zone expands to 40 m ahead of the working face.The high stress concentration and the expansion of the plastic zone aggravate the floor heave.Based on this,a ' lead-lag-stability ' phased cooperative control strategy is proposed,and the roof cutting parameters are determined to optimize the stress field.After the field application,the floor heave is reduced to 628 mm,which is 20.5 % lower than the theoretical value,which effectively controls the deformation of the roadway and improves the stability of the roadway.The research results provide theoretical and practical basis for floor heave control of gob-side entry retaining.

In order to explore the migration and failure characteristics and stress field evolution law of strong mining overburden in shallow buried extra-thick coal seam, this paper takes 226 upper 03 shallow buried extra-thick working face of Huangyuchuan Coal Mine as the research background, and analyzes the displacement field, stress field and fracture field of mining overburden through theoretical analysis and numerical simulation. The results show that the development height of overburden water flowing fractured zone in 226 Shang 03 working face is about 116 ~ 145 m, the first caving step distance of main roof is 44.74 m, and the periodic caving step distance of main roof is 18.27 m. Based on the numerical simulation results, it is revealed that the breaking of the main roof and key strata has a significant control effect on the surrounding rock in the stope area, which directly affects the development characteristics of the fracture field and displacement field of the overlying rock. The failure form of the overlying rock presents an ' inverted funnel ' shape as a whole, and presents obvious zonal migration and failure characteristics, namely : separation zone, fracture development zone, fracture closure zone and stable zone. The vertical stress peak of overburden rock is proportional to the disturbance degree and the advancing distance of working face, and it changes periodically after the working face advances to a certain length. During the mining process, the stress concentration area of overburden rock is mainly distributed on the coal wall side at both ends of the goaf, showing an ' eight ' symmetrical oblique divergence.

The mining of super thick coal seam causes more intense overlying rock activities. It is of great significance to accurately grasp the mining fracture variation law of super thick coal seam overlying rock for safe and efficient production of working face and protection of surface ecological environment. Taking the 2303 working face of a mine in Xinjiang as the engineering background, this paper intuitively describes the fracture characterization of overburden rock under the influence of mining movement of extremely thick coal seam based on discrete element numerical simulation, and reveals the development law of fracture zone and caving zone along with continuous mining of coal seam. The research results show that: The development height of caving zone and water-conducting fracture zone is 51.10 m and 148.11 m, respectively. The caving ratio is 5.77 and the fissure ratio is 16.63. With the advance of mining, the development of fracture zone and caving zone goes through three stages and two cycles: the height of fracture zone goes through a stage of development-growth-stability; The height of the caving zone experienced two cycles of sudden increase and slow decrease with the breaking of the old top and the subkey layer. Based on the discrete element numerical simulation results, fractal geometry theory is introduced and box covering method is adopted to accurately and quantitatively describe the development degree of mining overlays in extremely thick coal seams. The results show that: Under the influence of mining, the fracture development of overlying rock has excellent fractal characteristics. With the progressive advance of coal seam, the overall fractal dimension presents a dynamic change, and the overall fractal dimension presents a "saddle-shaped" feature with large at both ends and small in the middle. The average fractal dimension on both sides of the goaf reaches 1.001 and 0.978 respectively, which are the main water channels of the goaf. The development zone of the separate layer at the height of 150 m from the floor reaches 0.904, which is easy to accumulate groundwater. Based on the fractal dimension calculation results, the fractal dimension evolution curve is fitted, and the fractal evolution law of overlying rock cracks under different advancing steps is further revealed. It is inferred that the shape dimension reaches the maximum when the advancing distance reaches 71.18m, corresponding to the large-area roof caving stage. The research conclusions of this paper can provide reference and basis for the analysis of mining-induced fissure variation of overlying rock in super thick coal seam under similar conditions.

In response to the complex factors affecting the stability of roadway surrounding rock, based on the field investigation background of Balancheng Coal Mine, this paper adopts fuzzy cluster analysis method to study eight main factors affecting the roof strength, two-wall strength, floor strength, buried depth, top-to-height ratio (ratio of direct roof thickness to mining height), coal pillar width, maximum horizontal principal stress and average caving step, and establishes an evaluation model. The surrounding rock of the roadway is divided into five evaluation grades: very stable (Ⅰ), stable (Ⅱ), moderately stable (Ⅲ), unstable (Ⅳ) and extremely unstable (Ⅴ). The regression equation of surrounding rock stability prediction is established by using multiple stepwise regression analysis. The results show that the accuracy of simulation is 0.911, which can well reflect the quantitative relationship between the main influencing factors and the surrounding rock stability. The stability identification software of the surrounding rock of the roadway was developed, which could quickly identify the type of roadway, and the optimal design of support was proposed based on the classification results, which effectively reduced the deformation of the surrounding rock.

Aiming at the influence of mudstone bedding inclination Angle on its mechanical behavior and fracture response characteristics, taking mudstone samples from Caojiatan Coal Mine of Shaanxi Coal mine as the research object, laboratory tests and discrete element numerical simulation were used to explore the influence of bedding inclination Angle on mudstone mechanical behavior and its relationship with macroscopic crack evolution characteristics. The laboratory first carried out uniaxial compression tests on mudstones with different bedding inclination angles (0°, 15° and 30°). It was found that with the increase of bedding inclination Angle, the compressive strength of specimens under uniaxial compression decreased, the large penetrating cracks that dominated the macro-failure of specimens tilted to the horizontal direction, and the failure mode of rock mass gradually changed from brittle failure to ductile failure. In order to deeply explore the effects of weak bedding structure on the mechanical properties of mudstone specimens and the evolution law of microcracks, numerical models of different bedding angles (0-90 °) were established by using discrete element PFC numerical simulation software, and the weak bedding structure plane was realized by layering modeling and weakening the bonding contact parameters of interlayer particles. The results show that the uniaxial compressive peak stress, peak strain and elastic modulus of stratified mudstone first decrease and then increase with the increase of dip Angle. In the process of loading failure, micro-cracks occur first on the weak structural plane of bedding, the pre-cutting effect of bedding is obvious, and the generation and propagation attitude of large penetrating cracks are also controlled by the Angle of bedding plane. It shows that the existence of bedding structural plane has a significant deterioration effect on the bearing capacity of mudstone, and the influence of bedding Angle on the stability of surrounding rock and the early warning of the failure of rock bedding structure should be fully considered in the control of underground roadway surrounding rock.

To address the insufficient feature extraction of existing fault diagnosis models when dealing with nonlinear, non-smooth signals in noisy underground environments—which greatly reduces diagnostic accuracy—this paper proposes a shearer rocker gear fault diagnosis model based on the dual-branch fusion of SwinT and SKNet, enabling comprehensive extraction of both global and local features. The model consists of two branches, the simplified SwinT and the lightweight SKNet. The SwinT branch is integrated with a BAM module to further strengthen its global feature extraction capability. In the SKNet branch, ordinary convolution is replaced with depthwise separable convolution, and its fully connected structure is substituted with one-dimensional convolution, which reduces model complexity, improves efficiency, and facilitates deployment on mobile and edge devices. The experimental validation is carried out by using the shearer rocker arm loading test bench of Tai Heavy Coal Machine, and the results show that the accuracy and precision of the proposed method are higher than that of the comparison model, and the recognition accuracy still maintains more than 97% when the signal-to-noise ratio is SNR=-6, which fully proves that the method in this paper has a strong noise immunity.

Abstract: To address issues such as energy waste, response lag, and operational instability caused by fixed speed settings in traditional belt conveyor speed control methods, this paper proposes a dual-loop fuzzy PID speed control strategy based on the dynamic balance between coal flow and motor power. Based on the longitudinal dynamic model of the belt conveyor and the coal flow-motor coupling equation, the system equilibrium conditions and constraint conditions are derived to classify three typical operating conditions: safe, efficient, and transitional. This reveals the strong nonlinear correlation mechanism among belt speed, coal flow rate, and motor power. A hierarchical dual-loop fuzzy PID speed control architecture is constructed, comprising an outer-loop fuzzy controller and an inner-loop PID controller. The outer-loop fuzzy controller uses real-time coal flow and motor power as inputs, dynamically generating speed setpoints based on Mamdani fuzzy rules to achieve adaptive strategy energy optimization across the three operating conditions: safe zone, high-efficiency zone, and transition zone. The inner-loop PID precisely tracks the speed setpoint through feedback, suppressing dynamic fluctuations. Considering the coal flow-power balance relationship, this study proposes a dynamic coordination mechanism for dual-loop fuzzy-PID speed control, providing theoretical foundations and engineering implementation pathways for belt conveyor energy efficiency optimization. Test results demonstrate that this strategy enhances system dynamic response: speed setpoint update delay is less than 5 ms during coal flow step changes, actual speed response time is only 1.2 seconds, root mean square error of speed tracking is 0.09 m/s, and the proportion of high-efficiency operation reaches 89%, significantly improving system energy efficiency and control accuracy. By dynamically matching belt speed to load demand in real time, the system effectively reduces energy waste caused by light-load and no-load conditions. This enhances overall conveying efficiency and operational stability, providing crucial technical support for intelligent coal transportation and energy-saving speed regulation in mines, demonstrating significant engineering application value.

In order to investigate the impact on the evolution of the full-pore structure of coal under CO2 phase change impact fracturing , this study investigates the mechanism and influence of CO2 phase transition impact fracturing using coal samples subjected to CO2 fracturing and pristine structural coal samples from the same locations were selected from Dayun Coal Mine and Dahebian Coal Mine in Liupanshui, Guizhou Province, and the pore characteristics and fractal properties of the coal body before and after fracturing were analyzed by mercury intrusion porosimetry (MIP), low-temperature N2 adsorption test, and low-pressure CO2 adsorption test. and Combine the Merger, FHH, and Sierpinski models. The study shows that the pore structure of the original coal samples is mainly composed of slit pores formed by the accumulation of flake-shaped particles, and after the CO2 phase change shock fracturing treatment, a large number of ink bottle-shaped semi-open/open pores are generated in the coal sample, leading to further development of the pore structure. In the process, micropores develop into medium pores, medium pores develop into large pores, and large pores develop into larger pores, In other words, after CO2 fracturing, the number of micropores in the coal decreases, while the number of mesopores and macropores increases. Further analysis of the fractal properties showed that CO2 phase change impact fracturing exerted differential effects on the pore structures of micro-, meso-, and macropores within the coal body. For micropores, the fractal dimension increases, indicating that the pore structure becomes more complex and the non-homogeneity is enhanced. In contrast, for macropores, the fractal dimension decreases, suggesting that the pore structure becomes simpler and the non-homogeneity is weakened. For mesopores, in the low-pressure region (P/P0 ≥ 0.5), the fractal dimension also decreases, indicating that the pore structure simplifies, the pore surface becomes smoother and flatter, and the non-homogeneity was further weakened. However, in the high-pressure region (P/P0 < 0.5), there was no obvious pattern in the fractal dimension changes of the coal samples before and after CO2 fracturing. The results of engineering applications show that CO2 phase change shock fracturing technology can significantly reduce the gas flow attenuation coefficient and increase the permeability coefficient of coal seams, which can effectively improve the permeability of coal seams, reduce the gas content of coal seams, and improve the efficiency of gas extraction. This not only helps to improve the safety of coal mine production and reduce the risk of safety accidents such as gas outbursts, but also provides a strong guarantee for the efficient production of coal mines.

Given the challenges in quantitatively analyzing complex ionic species within high-salinity mine water and the dominance of SO?2? in both concentration and material erosivity, this research investigates how SO?2? concentration governs the mechanical behavior of coal gangue-based backfill materials to establish a theoretical foundation for co-processing both wastes into dual-waste backfill materials. We prepared specimens using coal gangue and simulated mine water (sodium sulfate solution at 0–30,000 mg/L SO?2?) as core components, adding a curing agent for consolidation, then tested compressive strength and performed SEM microscopy across curing ages. Results demonstrate that during days 1–7, moderate SO?2? boosts strength whereas excess concentrations weaken it, and by days 14–28, the 30,000 mg/L SO?2? group achieves optimal enhancement; SEM imaging at 28 days reveals escalating SO?2? concentrations drive denser interlaced networks of ettringite crystals and C-S-H gels while visibly reducing pores, aligning consistently with macroscopic strength progression. Specimens fabricated with sodium sulfate solution outperform tap-water counterparts in compressive strength, confirming the feasibility of dual-waste backfill synthesis.

Selective flocculation flotation, selective oil agglomeration flotation, selective flocculation - gravity separation - flotation and other technologies are new ideas for solving refractory coal slime. The key lies in expanding the particle size difference between fine clay minerals and coal particles. The paper selects polyaluminum chloride (PAC), which has certain selectivity for kaolin and coal particles, as the research object. It explores the morphological characteristics of the Fe3O4 - PAC composite agent prepared by the sol - gel method and the solvothermal method, as well as its selective flocculation effects on kaolin and coal particles. Furthermore, it studies the influence law of the mass ratio of Fe3O4 and PAC in the composite agent on the difference in sedimentation characteristics between coal and kaolinite. The results show that PAC has selectivity for the flocculation of kaolin, and the best effect is achieved when its concentration is 3%. In the preparation of Fe3O4 particles, the solvothermal method is superior to the coprecipitation method. The Fe3O4 particles prepared by the solvothermal method are uniformly spherical with a small particle size. Both the precipitation method and the solvothermal method can prepare the Fe3O4 - PAC composite agent, and the one prepared by the solvothermal method performs better in terms of floc sedimentation rate and the transmittance of the supernatant of the solution. With the increase of the proportion of Fe3O4 in the composite agent, the sedimentation rate of kaolin flocs accelerates, but the amount of the agent required to form an obvious interface also increases.

Traditional coal quality analysis methods are often characterized by cumbersome procedures, long testing cycles, and high resource consumption, making them inadequate for the demands of modern energy systems in terms of efficient utilization and safety assurance. Portable near-infrared (NIR) spectroscopy, with advantages such as rapid, non-destructive, and on-line detection, has broad application prospects in coal quality analysis. However, issues such as spectral peak overlap, high inter-variable correlation, and sensitivity to sampling conditions still limit modeling accuracy and stability. This paper proposes a multi-task feature decoupling U-shaped network based on portable NIR spectroscopy for the collaborative prediction of coal volatile matter and calorific value. First, an iterative outlier elimination strategy is developed using the Rairda criterion and Euclidean distance to enhance the reliability of modeling data. Second, various spectral preprocessing methods are compared, verifying the superiority of standard normal variate transformation in suppressing baseline drift and scattering effects. Next, a Unet-based shared-parameter module with an encoder–decoder architecture and skip connections is employed to efficiently extract shared features. Finally, a multi-task feature decoupling module is introduced, where orthogonal constraints and auxiliary prediction heads jointly optimize the separation of task-specific features while maintaining both inter-index correlation and specificity. Experimental results on 600 coal samples show that the proposed model achieves a root mean square error (RMSE) of 1.4255, mean absolute error (MAE) of 0.9600, and correlation coefficient (R) of 0.8086 for volatile matter prediction, and an RMSE of 1.2954, MAE of 0.9320, and R of 0.8584 for calorific value prediction—significantly outperforming various traditional machine learning and deep learning models. Furthermore, noise interference experiments confirm the model’s robustness and generalization capability under complex sampling conditions. This study provides an efficient, accurate, and highly adaptable technical approach for portable, multi-index, on-line coal quality detection.

This study investigates the vibration characteristics and stability of single-mass and dual-mass inertial vibrating feeders to support their optimal design and application. The research methodology involves establishing dynamic models and differential equations for both feeder types, computing rigid-body dynamic responses using Laplace transforms, and simulating material-feeder coupling forces through EDEM discrete element analysis. The amplitude-frequency characteristics under varying material loads are subsequently analyzed using practical engineering parameters. Results demonstrate that the dual-mass feeder requires only 20% of the excitation force needed by its single-mass counterpart, indicating superior energy efficiency. Within the 0-1 ton material coupling mass range, the dual-mass feeder exhibits significantly better stability, with an amplitude variation rate of 8.82% compared to 32.35% for the single-mass system. This enhanced stability originates from the dual-mass feeder's operation in the sub-resonance region, where the leftward shift of the amplitude-frequency curve caused by increased material mass counterbalances the amplitude reduction effect, thereby establishing a stable amplitude zone. These findings provide valuable insights for optimizing vibrating feeder design.

As an important equipment for fully mechanized coal mining face, the supporting scraper chain transmission system of the integrated anchor digging machine undertakes the important task of coal transportation. The tension control technology of the scraper chain drive system is of great significance to ensure the stable operation of the equipment and improve the production efficiency. In this paper, the tension control technology of the scraper chain transmission system of the anchor digging machine is studied, and an efficient and reliable tension control scheme is proposed. Firstly, the working principle and mechanical characteristics of the scraper chain transmission system were analyzed, and the key parameters and influencing factors of tension control were clarified. On this basis, combined with the actual working conditions of the anchor digging machine, a tension control strategy based on adaptive control was proposed. This strategy realizes the precise control of the tension of the scraper chain transmission system by monitoring the tension change of the scraper chain in real time, combined with the hydraulic transmission system and the system identification algorithm. In order to verify the effectiveness of the proposed control strategy, simulation and experimental studies are carried out. The simulation results show that the control strategy can accurately control the tension force of the scraper chain transmission system, and effectively avoid the problem of chain relaxation or over-tensioning. The experimental results further verify the reliability and practicability of the control strategy, and provide a new solution for the tension control of the scraper chain transmission system of the anchor digging machine. The research in this paper not only provides a new idea and method for the tension control technology of the scraper chain transmission system of the anchor digging machine, but also provides strong support for improving the production efficiency and safety of the fully mechanized coal mining face.