In view of the problems existing in the ordinary orifice flange grouting technology used in the directional drilling construction of water prevention and control in underground coal mines, such as slurry easy to precipitate, small grouting amount, and full hole section being filled, resulting in unsatisfactory grouting effect and a large number of repeated footage. On the basis of coal mine grouting stopper segmented grouting and coal mine underground hydraulic segmented pressure technology. Combined with un-derground construction characteristics, designed an MX-100 bare-eye packer, it has the structural features of single channel double flow structure and long rubber drum design and easy to detangle protective sleeve design. The Working performance of packer was verified by indoor performance test, and studying the technology of fixed point grouting for underground coal mine，it have formed a set of packer grouting technology. The technology has been applied in the construction of no.1 directional drilling hole of floor limestone in the directional drilling field of the bottom floor roadway of 15150 working face in Xin'an Mine, the outlet point is located in the hole depth of 391 m and the specific yield is 44 m3/h, the packer was set at a hole depth of 280 m successfully, the setting pressure is 10 MPa, the grouting pressure reached the designed 8 MPa finally and the total grouting dry material was 514 t. The amount of grouting is obviously increased compared with similar directional drilling using hole grouting technology. At the same time, 280 m directional drilling repeat footage was reduced. The experimental results show that the packer can be set firmly in open hole drilling，the technology of packer fixed point grouting can realize near horizontal directional drilling hole segment fixed point grouting，it also reduced the unnecessary repetitive footage. It provides a better technical support for the realization of underground water prevention and control project in coal mine.

Abstract: Introduced Long Coal Group Bird Mountain Coal Mine ultra-deep vertical well depth of more than 900 meters, static pressure of 9MPa, underground firefighting, sprinkler and water supply and salvage pipeline conventional pressure reducing valves to reduce the pressure, system failure is frequent, affecting the normal production of coal mines, the design proposes a downhole pressure measurement on the well throttling control of the deep-well water supply and decompression of the transformation program to reduce the pressure level of the pipeline and the cost of the valves, the system's reliability, stability enhancement, the failure rate is lowered! , with obvious economic benefits and reference significance.

In order to improve the refined and intelligent management of energy in coal preparation plant, the energy monitoring platform of low-carbon coal preparation plant is designed using digital twin technology. Based on the establishment of the digital twin of washing process flow line in coal preparation plant, the corresponding production control algorithm model is established through the unsupervised control technology of power supply and distribution, the intelligent control technology of heavy medium whole process and the intelligent control technology of slime concentration, so as to carry out visual monitoring and control of electricity, medium, medicine and water energy in coal preparation plant. The application of the platform shows that the platform can realize such functions as intelligent control of production process, intelligent regulation of energy consumption and alarm of abnormal energy use in coal preparation plant, so as to promote energy saving and consumption reduction.

In order to remove calcium, magnesium ions and silicon dioxide in high-salt wastewater and reduce the impact on the subsequent membrane process and evaporation process, the effects of salt content, reaction pH, and removal of calcium, magnesium ions and silicon dioxide in high-salt wastewater were studied. The results show that when sodium carbonate and magnesium chloride are added, the pH has a significant effect on the reaction of removing hardness and silicon, and when the pH is greater than or equal to 11, the calcium, magnesium and silicon can be reduced to a lower level simultaneously. In addition, when sodium carbonate and magnesium chloride were added, the removal rate of calcium, magnesium and silicon ions gradually decreased with the increase of salt content. Even if the pH was increased, the removal rate of ions could not be greatly improved, especially the removal of calcium ions.

The optical intelligent dry coal separator is a dry coal separation equipment based on advanced imaging and artificial intelligence technology, mainly composed of material system, recognition system, and execution system[1]. In the environment of container operation, a large amount of dust, coal ash, and coal slurry can easily cause the nozzle of the dry coal separator to clog, resulting in a significant decrease in the striking force and seriously affecting the separation effect[2]. In response to this problem, this paper proposes an optimization method for the nozzle, which can ensure that the nozzle has sufficient striking force during separation and can be used normally in harsh working environments. After practical testing, the optimized nozzlesignificantly improved the striking force, improved the material separation recognition rate, and brought significant economic benefits.

Unmanned, mechanized, and intelligent are important directions for the current development of mine construction. The full-face tunnel boring machine (TBM) has advantages such as high mechanization, automation, and high excavation efficiency. It has gradually been applied to coal mine inclined shafts and rock tunnel excavation projects. The influence of the geological characteristics of the Luohe Formation, which the Kekeng Coal Mine inclined shaft passes through, on the stability of the surrounding rock of the starting chamber for the inclined shaft TBM was analyzed. Field anchor pull force tests, in-situ strength tests, and single-element support shoe simulation tests were conducted and analyzed. A reinforcement plan for the surrounding rock of the starting chamber for long inclined shaft TBM and TBM support shoe was researched and proposed. The research results show that the anchor pull force of the surrounding rock of the starting chamber for the Luohe Formation can reach more than 100 kN; the average compressive strength of the tested section of the Luohe Formation surrounding rock is 23.1 MPa; when the compressive stress on the supported shoe reaches 33 MPa, there is no collapse or cracking of the surrounding rock. Based on the on-site test results, the rein-forcement of the top pipe shed of the TBM starting chamber, the top anchor net spray support in the excavation section, and the TBM advancing support scheme for entering the chamber were analyzed and proposed. Industrial experiments of direct chamber excavation using TBM in the Luohe Formation have verified the safety of the reinforcement tech-nology for the surrounding rock of the TBM starting chamber in the Luohe Formation. The research results can provide references for the design and construction of similar geological inclined shaft TBM direct chamber excavation schemes.

Addressing the substantial stability challenges in the expansive section top-coal roadways of the No. 3 coal seam in Li Lou Coal Mine, this research centers on the conveyance gateway of the 1300 working face. Employing a synergistic approach of numerical modeling and empirical laboratory testing, the project aims to engineer high-strength structural components vital for maintaining the integrity of the surrounding strata in these roadways. The initial phase involves the conceptualization of a robust protective support system tailored for top-coal roadways. This is followed by a comprehensive assessment of U29 type steel anchor beams and expandable framing systems through a combination of simulation studies and controlled laboratory experiments. Results indicate a marked superiority of π-type steel over the U29 steel variant, which had exhibited an escalated deformation of 275%, in terms of deformation resistance, maintaining near-constant deformation levels under stress. The load-bearing efficacy of π-type steel beams surpasses that of U-shaped steel by an average of 4.7% under vertical load conditions and 12.0% under inclined load scenarios. Additionally, when subjected to vertical and dynamic impact loads, π-type steel beams exhibit a 5.0% enhanced load-bearing capacity. The study observes an increase in the maximum deformation of the arch structure with its height and width, yet finds no significant relationship between the width-to-height ratio and arch deformation, indicating a preference for arches with rounded corners. The impact of vertical loads on arches is pronounced; more uniform force distribution correlates with minimized arch deformation. Under eccentric loading, the arch's upper central region remains the focal point of maximum deformation, which diminishes as the central load is reduced, and significant horizontal displacement is observed at the support legs, especially around the curved shoulder areas. Structural designs featuring four and five segments significantly outperform the traditional three-segment approach. Strategically placing nodal points at the arch legs proves more effective in facilitating the overall stress accommodation of the arch. This research contributes valuable theoretical insights for designing tunnel supports under analogous geological settings.

The mining pressure manifestation in the longwall fully mechanized mining face is an important factor affecting the safety production of coal mines, and its strength analysis and effective monitoring are of great significance to ensure the stability and safety of the mining face. Based on the roof conditions of Chahasu 31319 working face, the specific indicators of mine pressure display of working face were determined, and the basic roof load of the working face and the initial and periodic pressure step distance of the working face were calculated; the basic roof mechanical bearing model was established, the roof stability analysis was carried out, and the roof of 31319 working face was analyzed in combination with the roof separation conditions; the stope partition bearing model was established by using the elastic foundation beam theory, The stope is simplified into original rock I zone, support II zone, goaf non-collapse III zone and goaf collapse IV zone, The variation characteristics of mechanical parameters such as mechanical deflection, rotation angle, bending moment, shear force and other mechanical parameters of the basic roof of the working face in different mining stages are obtained: the deflection curve image of the basic roof under different loads shows a parabolic change of the opening downward, the overall change of the rotation angle is an "S" shape, the bending moment is a parabolic change of the opening upward, and the shear force changes linearly. Combined with the theoretical analysis results, the monitoring content of mine pressure in the fully mechanized mining face of 31319 and the layout method of measuring points are proposed. The research results can lay a key foundation for the prevention and control of roof disasters on the working face and the safe and efficient mining of coal mines.

Compared with ordinary stone gate uncovering coal, long-distance coal uncovering in inclined shaft is high risk and difficult. In order to ensure that the shaft safely and efficiently passes through the outburst coal seam, the technical difficulties for long-distance coal uncovering of inclined shafts were analyzed, and safety measures for uncovering outburst coal seam proposed, based on the geological exploration results, support design and measured gas parameters of the coal seam No.3 in the coal uncovering area. By using the guide tunnel hole layout, a comprehensive enhanced extraction technology system of "six in one", such as increasing the hole depth with large aperture, multiple " burrowing holes ", casing down, high negative pressure, gas lift reverse circulation slag cleaning, and curing intercept extracting, has been put forward, which significantly improves the construction quality of drilling, solves the problem of efficient extraction of long distance exposed strong outburst coal seam in inclined shafts, and effectively controls the amount of gas emission after exploding.The method of vertical uncovering strong outburst coal seam at one time in inclined shaft is adopted, which significantly increases the range of uncovering coal at one time. The problem of roof and forming control in coal passing section is solved by the method of dense hole slotting for contour lines pretreatment for inclined shaft contour. It took 36 days from uncovering the coal seam No. 3 to passing through the coal seam at the vertical distance of 3 m. The maximum gas concentration in the working face after the blasting was 0.68%, and the maximum gas concentration in the return air flow was 0.36% during uncovering the coal. The operation of inclined shafts uncovering coal was successfully carried out, which provides important reference significance for long-distance uncovering outburst coal seams under similar conditions.

In order effectively avoid the occurrence of goaf water hazard, the method of geophysical exploration combined with drilling in the goaf area is explored, and the comprehensive treatment measures are adopted. Based on seismic wave anomalies in the gob, the location and scope of the goaf region are delineated by three-dimensional seismic. There is a great difference between the resistivity of goaf area and surrounding rock. The low-resistivity anomaly area is determined by transient electromagnetic method, and the goaf area is further explored. The goaf area delimited by three-dimensional seismic and transient electromagnetic method was verified through the construction of ground drilling, and the goaf area was explored by controlled source charging method using the borehole to reveal the goaf area. The potential difference contour line of different frequencies was used to verify and correct the scope and location of the goaf area. After the exploration of the goaf area of the closed mine by geophysical exploration and drilling, the water in the goaf area was drainaged by underground long distance directional drilling and ground drilling respectively, and the water in the goaf area was pumped out by the ground large-diameter drilling combined with high-flow submersible pump and booster pump in pipeline. The research results show that the location and scope of the goaf area can be accurately delineated by geophysical exploration combined with drilling, and the water in the goaf area can be drainaged and pumped by underground drilling and ground drilling respectively, which can effectively solve the threat of goaf water hazard to the surrounding coal mine.

When the pre-excavation single ( double ) retracement roadway is used to stop mining in the fully mechanized caving face of the thick coal seam, strong mine pressure, broken coal wall, and large deformation of roof occur in the stopping space, resulting in resistance to withdrawal. To study the reasonable stop mining method of the joint surface under this working condition, through the methods of field investigation, laboratory test, principle comparison, numerical analysis, and field monitoring, the comparative study of mine pressure behavior of different retracement methods of fully mechanized caving face in thick coal seam is carried out. The study shows that the pre-excavation single retracement roadway has the superposition of the advance abutment pressure of the working face and the abutment pressure of the roadway ( the increase coefficient is 3.37 ). On this basis, the pre-excavation double retracement roadways increase the superposition with the stress of the coal pillar ( the increase coefficient is 3.69 ), and the self-excavation withdrawal channel has no stress superposition during the stop mining period ( the increase coefficient is 2.53 ). At the same time, the comprehensive comparison of the advance abutment pressure, maximum shear stress, and the principal stress zoning shows that the arrangement of the self-digging retracement channel at the stop line position has the lowest mining pressure. Therefore, the stop-mining process flow based on self-excavation and retracement roadway is established. Based on the monitoring of the deep hole displacement of the roof, the support parameters of stop-mining large section space are designed and verified by pre-stress field simulation. Through field practice, the effective support of the stopping space and the smooth retracement of the supports are realized.

Based on the engineering background of 11101 transport channeling in Qizhijing Coal Mine (East District), the optimization of charging parameters of non-pillar cutting shaped blasting in thick coal seam is studied. In this paper, through the mechanism study of roof-cutting blasting and the theoretical study of charging parameters, and using numerical simulation to carry out single-hole and multi-hole blasting validation, the roof-cutting aggregation blasting test was designed for the engineering situation of 11101 working face. The results show that the fracture rate of broken roof mainly composed of sandy mudstone is lower than that of sandstone roof and intact roof. At the same time, it is found that when the roof in the sealing section is sandy mudstone, the orifice will be damaged to a certain extent. The pre-fissure and slit effect of stope roof directly influences the filling effect of goaf gangue and then influences the stress transfer of overlying strata. The relevant conclusions are verified by the field blasting test, and the blasting technical parameters suitable for the 11101 working face of Qijingjing Coal mine (East District) are determined, which is a key technology to guide the top cutting pressure relief.

The hard and thick roof slabs are usually controlled by deep hole roof breaking blasting to relieve pressure and prevent rock burst. After blasting, the CO gas exceeding the limit interferes with the prediction of coal seam spontaneous combustion. To reduce the impact of harmful gas CO from blasting on determining coal spontaneous combustion, through laboratory experiments to analyze the main harmful gases produced by emulsion explosives used in Kuangou Coal Mine. Analyzing and elucidating the CO gas diffusion mechanism after blasting based on on-site CO sensor monitoring data. On site testing uses discharge system to discharge CO gas from the blasting hole. Based on on-site monitoring data, investigate the effectiveness of the drainage system, optimize the parameters of the drainage system, and determine the optimal drainage flow rate and roadway air supply volume. The research results indicate that the Kuangou Coal Mine emulsion explosives after the explosion, the main harmful gas is CO; After blasting, CO gas mainly gushes out from the blasting hole and forms a smoke cluster in the roadway, the CO gas volume fraction occur to sharp change in the monitoring data. The CO gas slowly released through blasting holes, coal rock fractures, and coal detachment. In addition, the CO gas accumulation or adsorption in the goaf, as well as ventilation and other factors, result in CO gas volume fraction sharp change and slowly decreasing; The drainage system can maximum shorten the return air CO gas overrun time by up to 38 minutes, and maximum reduce the return air CO gas volume fraction peak by 45%; Under different conditions of roadway air supply volume and drainage system flow rate, the drainage effect is better when air supply 1400m3/min and drainage flow 50m3/min; Increasing the tunnel air supply volume can accelerate the blasting fume migration rate and shorten CO gas overrun time, but it will also have a certain impact on the drainage system gas collection port.

Abstract：In the AC/DC distribution network of coal mines with distributed power sources such as photovoltaics, there are factors that cause DC voltage fluctuations, such as uneven illumination and load fluctuations. In order to reduce the influence of these fluctuations on system stability, this paper proposes a control strategy that introduces the photovoltaic output voltage and motor load current as feed-forward links on the basis of the traditional single-loop control structure of photovoltaic system. Attenuate DC link voltage fluctuations caused by these two factors. A simulation model of AC/DC hybrid distribution network in coal mines is built in PSCAD/EMTDC, and the effectiveness of the proposed control strategy is verified by comparing the maximum power point tracking (MPPT) control strategy, MPPT-traditional voltage regulation switching control strategy and the DC bus voltage characteristics under the control strategy proposed in this paper.

In response to the problem of rules of overlying rock fracture and difficulty in determining the stability of overlying thin coal seams in shallow buried thick coal seam mining faces, a large-scale similarity simulation model was constructed based on the working face of the eight panel area of Sandaogou Coal Mine. The theoretical analysis, similarity simulation, and on-site measurement methods were combined to study the fracture and migration laws of overlying rock and the stability of overlying thin coal seams after mining. The research results showed that: ① the second layer of fine-grained sandstone layer on the 5-2 coal seam of Sandaogou Coal Mine is the basic strata, and the first strata of fine-grained sandstone strata above the 4-3 coal seam is the main key strata. The basic strata cycle fracture step distance is about 14 meters. ② With the backfilling of the 5-2 coal seam, the collapse fracture zone above the working face develops in an inverted trapezoidal shape upwards. When pushed up to 160 meters, the stability of the overlying 4-4 coal seam will significantly decrease, resulting in a large number of oblique fractures. Separation will also occur between the 4-3 coal seam and key stratas. When pushed up to 240 meters and beyond, it will affect the surface.③ After the completion of the 5-2 coal seam mining, the overlying 4-4 coal seam and 4-3 coal seam both exhibit a disc-shaped sinking shape, and the stability of both coal seams decreases, resulting in a large number of cracks. However, the overall continuity is still maintained, and delamination may occur in the rock beam hinge zone.

In response to the issue of impact disasters induced by discontinuous unloading of wide coal pillars in Sandunzi Coal Mine, through on-site measurement and theoretical analysis, the pressure characteristics, coal pillar stress distribution characteristics, and microseismic activity characteristics of the unloading and non unloading areas were studied. An analysis model of impact induced by discontinuous unloading of wide coal pillars was established, revealing the mechanism of rock burst induced by discontinuous unloading of wide coal pillars. Based on this, the prevention and control methods for rock burst of wide coal pillars were explored, The research results indicate that under the action of the overlying lateral roof and advanced support pressure, the stress concentration area will transfer towards the middle of the un unloaded coal body, which is prone to unstable instability. The dynamic load disturbance caused by the sudden rupture of the complete roof rock layer is also the main reason for the impact of the wide coal pillar. Finally, it is proposed that the combined anti erosion method of continuous pressure relief of wide coal pillars and weakening of thick and hard rock layers can help prevent and control rock burst induced by wide coal pillars. The research results will provide technical support for the prevention and control of induced impact disasters in wide coal pillars in China's coal mines.

To increase the permeability of coal seams and improve the gas extraction rate, based on the TNT equivalent conversion of CO2 airburst energy release, LS-DYNA software was used to analyse the influence of blasting parameters (load volume, peak pressure relief and fracture hole diameter) and the effect of geostress on the effect of liquid CO2 phase change fracturing, and liquid CO2 phase change fracturing engineering tests were carried out on the working face of 109 in a mine. The simulation results show that the effect of liquid CO2 phase change fracturing is positively correlated with the change of load volume, peak pressure and fracture hole diameter, and negatively correlated with geostress, and the load volume and fracture hole diameter should not be too large; the test results(3.62m) show that the effective fracture radius of the coal seam is close to the simulation results(3.47m), which verifies the reliability of the numerical model of blasting, and the increase of penetration of the coal seam by applying liquid CO2 phase change fracturing technology. After applying the liquid CO2 phase change fracturing technology to increase the permeability, the permeability coefficient of the observation holes at a distance of 1m from the fracturing holes increased by 34 times, the intensity of gas outflow from the observation holes at a distance of 2.5m from the fracturing holes increased by 3.57 times and the intensity of attenuation was reduced by 63.16%, and the average concentration of gas extraction from the observation holes at a distance of 1m-1.5m from the fracturing holes was increased by 64.38%.

The study of gas outflow from coal tunnel working face is of great significance for the prevention and control of gas in coal tunnel working face. Using the characteristics of deep learning theory and long and short-term memory neural network to process the time series samples efficiently, a prediction model of gas outflow prediction model based on LSTM neural network is established. The hyperparameters of the model are optimised according to the size of the loss value in the training process, and the optimal hyperparameters of the model are selected and determined. With the help of the original data of gas outflow from the coal mine face, the applicability and accuracy of the model are verified, and the variation trend of gas emission in time dimension is analyzed according to the predicted results. The results of the study are of reference significance for predicting the trend of gas outflow in coal mine face, identifying abnormal gas outflow in the face, and improving the level of gas control in the face.

The extraction of coal seam gas by drilling is the fundamental measure of coal mine gas management, however, due to the constraints of coal seam conditions, the drilling process of gas drilling often encounters problems such as jamming and plugging, which affect the hole formation effect of drilling, and then affect the efficiency of gas extraction. In order to minimize the occurrence of jamming during gas drilling, a sodium-based bentonite-based microfoam drilling fluid was developed in this paper to achieve a smooth drilling process.Firstly, the ratio of its main components was optimized, and the best drilling fluid preparation system was determined through orthogonal tests. The experimental results show that the drilling fluid has good foaming performance, remains stable up to 80℃, and has good erosion resistance to coal dust with mass fraction within 10%; the rock chip settling rate characterizes that the drilling fluid has better rock-carrying ability than ordinary water. Finally, the ability of the drilling fluid to carry coal dust at different flow rates and rotational speeds was analyzed by numerical simulation to evaluate the coal dust-carrying effect of the drilling fluid during the drilling process.

Rapid and effective identification of mine inrush water sources is a prerequisite for mine water control measures development, while the accurate quantification of different sources of water influx, and accordingly formulate targeted prevention and control measures is the key to ensure the safe production of the mine. Therefore, using Yangcun coal mine as a research example, and based on the analysis of mine water filling source, 56 study samples selected in four major recharge aquifers, 52 typical samples were retained after removing abnormal samples using Piper's trilinear plot. Selection of six conventional ions as discriminators which are HCO3-、SO42-、Cl-、Na++K+、Mg2+ and Ca2+, and Bayes stepwise discriminant analysis method in multivariate statistics was used to establish the discriminant model of mine water inrush source. The accuracy of Bayes discriminant model for the overall classification of samples reached 91.06 %. It lays a foundation for effective identification the proportion of mixed water source composition. Afterwards, a mixing model was developed with the "M3" mass balance theory and the composition of the mine water influx was determined. The results show that: restricted by the characteristics and influence degree of the water-filled aquifer, the sandstone water content in the early mine water inrush composition is higher, specifically, the Ordovician limestone water accounts for 15.2 %, the Shixia limestone water accounts for 20.68 %, the No.3 coal roof sandstone water accounts for 48.28 %, and the No.13-14 limestone water accounts for 15.85 %. With the passage of time, the proportion of 13-14 ash water and Ordovician ash water gradually increased, among which Ordovician ash water accounted for 23.65 %, 10 ash water accounted for 10.8 %, 3 coal roof sandstone water accounted for 26.73 %, 13-14 ash water was 38.83 %. This is consistent with the situation that the No.3 coal in the fifth mining area is mainly mined in the early stage of the mine, and the lower coal group is gradually mined in the later stage, indicating that the method is more in line with the actual production. On the whole, the Ordovician limestone water accounts for 17.5 %, the Shixia limestone water accounts for 19.86 %, the No.3 coal roof sandstone water accounts for 36.43 %, and the No.13-14 limestone water accounts for 26.21 %. It shows that the current mine inrush water is dominated by the roof sandstone water in the No.3 mining area and the No.13-14 limestone water in the lower group of mining area, which provides a basis for the future development of water control work in the mine.

In order to solve the problems of poor toughness, brittle failure and instability of gangue cemented backfill during deep filling mining, waste tire steel fiber was used to improve the mechanical properties of gangue cemented backfill. The stress-strain curve characteristics, constitutive model and the action mechanism of waste tire steel fiber were studied by uniaxial compression test. The results show that the peak strain increases significantly, but the peak stress decreases, the post-peak curve is gentle, the residual strength is high, and the filling body changes from brittle failure to ductile failure. The modified constitutive model can reflect the stress-strain relationship and the residual strength characteristics of steel fiber backfill mixed with waste tire well. The scanning electron microscopy showed that the waste tire steel fiber was not directional embedded in the backfill matrix, and bonded with the hydration products, resulting in crack resistance effect, which increased the toughness of the backfill. The research can provide theoretical basis and engineering design reference for steel fiber modified gangue cemented backfill of waste tire.

In the parameters optimization of surface mining process, It is necessary to construct a suitable model for solving the problem by using the conventional optimization method. However, there are often difficulties in modeling and solving problems in engineering problems. Aiming at this, the simulation method of process parameters is proposed, The core idea is " to determine the logic flow of the system - to extract the underlying drive events - to determine the simulation type and clock simulation method - to build the system state of the quantitative model - simplify control logic - build drive event quantization model - replay system ". This paper studies the application of the overcast stripping technology in Heidaigou surface mine, the logic flow of the system is decomposed into three layers, the basic operation of the equipment is the driving event of the system; the center of gravity circle projection method is proposed to simplify the system control logic, and the system storage state model based on the three-dimensional model is constructed; The discrete event system modeling is selected and the simulation process is advanced by the event step method. The simulation results show that the system efficiency is maximized when the bench height is 13m, and the error is minimized when the simulation correction coefficient is 0.94.

The automatic detection technology of exposed cross-sections is the basis for intelligent control of the suspension height of airborne-coupled ground-penetrating radar antennas. When low-frequency airborne-coupled ground-penetrating radar is used for long-distance exploration in well mining coal mines, the exposed cross-sections exhibit characteristics of approximately horizontal straight lines. Currently, it mainly relies on expert manual interpretation, which cannot meet the industrialized requirements of real-time, intelligent, and efficient applications. Therefore, this study proposes a micro-rough exposed cross-section automatic detection method based on peak detection algorithm and grid-based quadratic linear fitting method. A window-constrained average method is proposed to effectively filter out direct waves while preserving the detailed response characteristics of the target interface. The time-varying deconvolution method is used to suppress the convolution effect caused by overlapping waveforms to improve waveform quality. A peak detection algorithm based on the idea of local extremes is proposed to automatically extract the peak position information in the A-scan graph of ground-penetrating radar. A grid-based quadratic linear fitting method is proposed to map the peaks to a two-dimensional grid and perform linear fitting. Based on the correlation coefficient and first-order derivative of the fitting curve, the curves are classified, and secondary linear fitting is performed to automatically extract the position labeling and coordinate information of layered target interfaces. Engineering experimental methods are used to verify the applicability of this method.

Aiming at the problem of rolling bearing fault diagnosis of key components of mine ventilator in high noise environment, an end-to-end bearing fault diagnosis method based on residual network is proposed. By introducing the residual learning framework, the robustness of the network to noise is enhanced. The model is systematically verified by using the bearing vibration data set of Baode Coal Mine in North China, and the key hyperparameters affecting the performance of the model are further determined. The optimization of convolution kernel size and batch size provides higher diagnostic accuracy and stronger noise anti-interference ability for the model. The results show that the fault diagnosis rate of the ResNet34 model is close to 90 % in a noisy environment with a signal-to-noise ratio of 0, and the accuracy rate can reach more than 54 % even when the signal-to-noise ratio is reduced to-10 dB. It provides an effective solution for the fault diagnosis of ventilator rolling bearing in complex mine environment, improves the accuracy, timeliness and reliability of bearing fault diagnosis, ensures the reliable operation of equipment and the sustainable production, and is of great significance to ensure the safe production of mines.

In order to solve the problem that the operator has insufficient or excessive antifreeze spraying due to mistakes and fatigue in the process of coal mine coal transmission, resulting in the adhesion or slippage of coal and the conveyor belt, and then causing production accidents, an automatic antifreeze spraying system for coal mine conveyor belt based on visual monitoring was developed. Through the detection, recognition and classification of on-site conveyor belt images by edge algorithms, the system issues remote control instructions to the antifreeze valve to complete the automatic spraying of antifreeze. A u-net-based image data augmentation method (U-NHME) was introduced to augment the original dataset samples, and then YOLO-V7 was used as the network for target localization and recognition, so as to achieve accurate recognition of all-weather outdoor images. Map and other evaluation indexes were used to enhance, train and recognize images with different coal quantities. Experimental results show that compared with the original YOLO-V7 network, the recognition accuracy of the proposed algorithm is improved by 2 percentage points, and the recognition accuracy of conveyor belt coal quantity is improved. The system is highly reliable and scalable, bringing a more efficient, safe and environmentally friendly production method to the coal industry.

The excavating boom is subjected to complex forces and variable loads during the excavation process. It is difficult to obtain the load spectrum of the articulation point using actual measurement. To determine the fatigue life accurately under real working conditions, this paper utilizes the discrete element principle and EDEM-ADAMS coupled simulation method to analyze the excavation process of the excavator under different conditions. During the analysis, the load spectrum of each articulated point of the excavator boom is obtained under different excavation media and unbalanced loads. The stress and strain distribution of the excavator boom is then determined under different excavation conditions using Workbench software. The minimum fatigue life of the boom is calculated under various working conditions using the S-N fatigue life analysis method in combination with Ncode software. Additionally, areas prone to fatigue damage are identified for the excavator boom. The excavator boom fatigue life analysis accuracy is improved by using accurate material models under different working conditions. By reflecting the load spectrum obtained in actual working conditions, it provides the basis for reliability design.

Aiming at the difficulty in preparing high concentration lignite water slurry (LWS), a compound dispersant was prepared based on the compound of Na2CO3 and sodium methylene dinaphthalene sulfonate (NNO). The effects of NNO and the compound dispersant on the LWS properties were investigated. The changes in zeta potential, contact angle, pore structure and pore size distribution of LWS particles with different agents were analyzed to explain the mechanism in slurry concentration and rheological properties. The results show that the concentration increased from 59.89 wt% to 60.53 wt%, and the yield stress increased from 24.12 Pa to 38.85 Pa when the slurry was made with the compound dispersant. Besides, the fluidity index decreased from 0.69 to 0.56 indicating that the pseudoplasticity increased by Na2CO3. The absolute value of zeta potential increased from 28.3 mV to 36.1 mV and the contact angle decreased from 74.5° to 65.3° after NNO adsorption on lignite. With the addition of Na2CO3, the absolute value of zeta potential decreased to 34.6 mV and the contact angle decreased to 57.5°. Compared with NNO, the specific surface area of the particles decreased from 2.7442 m2/g to 2.4264, the content of macropores decreased from 70.71% to 54.15%, while the content of mesopores increased from 25.68% to 41.27%. These results indicated that Na2CO3 optimizes the ionic environment in the coal-water slurry system and promotes the adsorption of NNO on the surface of lignite particles, which reduces the contact angle and zeta potential, causing the viscosity reduction. In addition, Na2CO3 formed precipitates with the metal ions dissolved in LWS system so that the pores was plugged and drove more free water releasing, thus reducing the apparent viscosity of LWS.

To confirm the technical feasibility of CO2 mineralization for multi-source solid waste treatment, the typical industrial solid waste, coal fly ash and calcium carbide slag in northern Shaanxi were selected in this paper to explore their CO2 mineralization performance and physicochemical properties before and after reaction, as well as their interaction during CO2 mineralization. The results show that the CO2 removal efficiency (50 %) and CO2 sequestration capacity 5.0 g/kg) of coal fly ash were very limited. Compared with coal fly ash, calcium carbide slag showed a higher CO2 removal efficiency (90 %) and CO2 sequestration capacity (340 g/kg), respectively. However, in the process of CO2 mineralization, the CO2 mineralization reaction on the surface of calcium carbide slag particles was very intense, resulting in the rapidly generated CaCO3 coating the unreacted calcium carbide slag particles, thus reducing the amount of CO2 sequestration capacity. When coal fly ash and calcium carbide slag was mixed for the synergic CO2 mineralization, coal fly ash particles not only provided the precipitation crystallization site for calcite, but also dispersed the calcium carbide slag particles, preventing the newly formed calcite from covering the unreacted calcium carbide slag particles, which promoted the reaction of calcium carbide slag, and increased the CO2 sequestration capacity of coal fly ash and calcium carbide slag mixture. The fly ash produced by coal mining is prepared into slurry with calcium carbide slag and mine water to mineralize and seal CO2 in the flue gas. After mineralization, the slurry is backfilled into the mine through pipes, which not only helps to reduce CO2 emission, but also reduces the agglomeration of particles in the slurry. It is of great significance to the utilization of fly ash resources, the utilization of coal goaf space, the utilization of mine water and the reduction of carbon emission of power plants under the coal-power joint operation mode．

The composite lipid collector was composed of methyl oleate (MeO), methyl laurate (MeL) and amyl benzoate (nAB) according to the mass ratio. The flotation effects of different types and amounts of composite lipid collectors on low-order long-flame coal were studied. The microscopic interaction mechanism between different types of composite collectors and low-order long-flame coal was investigated by molecular dynamics method. The results show that compared with traditional kerosene collectors, the composite lipid collector can significantly improve the floatation efficiency of low-rank long-flame coal, and the flotation efficiency of ternary composite MeO/MeL/nAB collector is significantly better than that of binary composite MeO/nAB or MeO/MeL collector at the same dosage. The adsorption mechanism of different lipid collectors on the coal surface was revealed by molecular dynamics simulation of the adsorption configuration of the collector and the interaction between the collector and the coal surface. Compared with the binary composite collector MeO/MeL and MeO/nAB, the interaction between the terpolymer collector MeO/MeL/nAB and the coal model was stronger, and the flotation effect of low-rank coal was better.

The foaming and bonding phenomenon occurs in the coarse slag particles of coal water slurry gasification after high temperature roasting, which provides a basis for the preparation of foam materials. In this paper, the single variable method is used to explore the effects of slag amount, roasting temperature and holding time on the compressive strength and volume density of foam materials, using Ningdong four nozzle coal water slurry gasification slag as raw material. The results show that, under the conditions of 1.25mm~5mm coarse slag particle size, 14g coarse slag amount (fixed volume mold), N2 roasting atmosphere, 750°C roasting temperature and 10min holding time, the compressive strength of the prepared foam material is higher than 1.5MPa, and the volume density is lower than 0.5g/cm3. The electromagnetic wave absorption performance of the material is: when the material thickness is 7mm, the minimum reflectance loss value is -22.14db (16.80GHz), and the effective bandwidth is 1.88GHz. Its absorption of electromagnetic waves is mainly reflected in the 16~18GHz frequency band, and the absorption loss mechanism is mainly the magnetic loss effect of ferrite in the gasification slag. It can provide new ideas for the preparation of foam materials and the application of foam materials in the field of electromagnetic wave absorption.

Aiming at the low construction efficiency of the traditional roadway support method, which limits the tunneling efficiency, a new type of support bracket is designed. The three-dimensional assembly model was established by Solid Works, and the static load characteristics of the temporary support bracket were analyzed by ANSYS Workbench software using the two loading methods of internal loading and intermediate external loading for the bracket. The results show that the deformation of the bracket in the case of intermediate external loading is 10.27 times of that of internal loading, and the stress and strain are 2.14 and 2.13 times of that of internal loading, respectively; the deformation of the bracket in the case of internal loading mainly concentrates in the vicinity of the articulation point of the cover frame and the counterbalance jacks, whereas the deformation of the bracket in the case of intermediate external loading mainly concentrates in the front end of the upper beam frame; the stress and strain of the bracket in the case of internal loading mainly appear in the hinged point of the upper beam frame and the supporting jacks. In the case of internal loading, the stress and strain of the bracket mainly appeared in the articulated lugs of the upper beam frame and the supporting jacks, and the articulated lugs of the cover frame and the balancing jacks, whereas the stress and strain of the bracket in the case of intermediate external loading mainly appeared in the contact area between the loading plate and the upper beam frame, and the cover frame and the front connecting rod also had more obvious stress and strain; By choosing the right material, the bracket can be made highly reliable in both loading methods..

In view of the safety problem that rubber-tyred drilling rig should be braked in the emergency of underground transfer site, the working principle of the brake system is analyzed, and the redundant design concept is adopted, a kind of full hydraulic wet brake system is designed from the aspects of hydrostatic closed brake system and mechanical wet brake, which makes the brake system meet the requirement of bad working condition. At the same time, aiming at the problem of the instability of the parking brake pressure, the analysis and calculation are carried out, and the accumulator group is optimized to achieve the goal of safe parking. The test results show that the whole system has the advantages of high parking torque, stable release pressure, safe and reliable braking performance, quick response, and braking distance less than 8 m, which effectively solves the safety problem of emergency braking when the rig is moved.