Abstract: The directional blasting top cutting and pressure relief technology has played an active role in the prevention and control of coal mine disasters. However, due to the complex and diverse geological conditions of coal mines, a set of completely universal blasting parameter design schemes has not been found to meet the requirements of different environments. In order to achieve the expected goal of directional blasting to protect the anti-separation coal pillars in the 3309 working face of a mine in Hebi, based on the actual geological conditions, two numerical models before and after roof cutting and pressure relief were established using FLAC3D software and ANSYS/LS-DYNA software. Different uncoupling coefficient directional energy-concentrating blasting models, the numerical simulation results show that the stress peak value after roof cutting and pressure relief is about 19% lower than that without roof cutting, and the distance between the peak position and the side of the 3309 coal pillar is obvious compared with that without roof cutting increase, the stress environment in the area near the 3309 upper groove is improved; taking the crack propagation length as the analysis index, considering the cutting effect and improving the utilization rate of explosives, the optimal charge structure with a decoupling coefficient of 1.7 as the normal section is adopted. According to the above numerical analysis results and the distribution of faults, a systematic and differentiated blasting parameter design was carried out for the 3309 upper trench. Industrial experiments showed that the directional blasting effect of roof cutting and pressure relief was good, which could meet the actual engineering requirements. A reference is provided for blasting protection of water-proof coal pillars.

The layout of the first level mining in Shaliang Coal Mine was significantly changed by the influence of the two significant faults, F1 and F2, and their secondary faults in the minefield, resulting in a significant reduction in the layout area of the regular fully mechanized mining face. In order to optimize mine mining layout and improve coal seam recovery rate, the paper proposes to arrange a short-wall or special-shaped strip filling mining face in the multi-fault cutting area of the mine and replace the coal pillar with multi-cycle filling mining. The research shows that the test C135206 working face of Shaliang Coal Mine is in the base-load ratio JZ < 0.8 and base-mining ratio JC < 9, and the strip mining width is in the limit span range determined by the direct roof breaking criterion. Using the triple reference process type parameters of ' mining 6.6 and leaving 19.8 m ' is appropriate based on a continuous mining machine. The triple reference type adopts four-wheel sequential mining and filling cycle. The mining and filling process is suitable for continuous mining and filling of single-wing single-working face, large-cycle arrangement of the multi-working face in two wings of the main roadway and complete separation of mining. The roof-contacting method of laying multi-channel grouting and gas pipeline on the roof of the working face strip roadway can realize the full roof-contacting of the filling body, and the high-efficiency anti-blocking at both ends of the strip roadway can be realized by using the baffle ( wall ). The research provides a new idea for optimizing the layout of horizontal mining in Shaliang Coal Mine and effectively improving the recovery rate of the mine.

Aiming at the harm of pulverized coal production in horizontal wells in broken soft and low permeability coal seams, A new concept of hydraulic jet perforation and fracturing is proposed，It can realize permeability enhancement and pulverized coal control,the specific processes include hydraulic jet perforation, high-pressure jet, annulus fracturing and hydraulic jet perforation cleaning.Through the comparison of cost and process, drag tubing hydraulic sand blasting perforation fracturing is selected, and the process and key tools are optimized. First, optimize the integrated cemented carbide conical convergent nozzle to prevent reverse erosion damage, which can achieve a jet pressure of 16.5-25.8MPa when the displacement is 2.0-2.5m3/min. Secondly, optimize the ejector body, which can effectively shoot through the casing and cement plug, and shoot into the rock to a certain depth. The supporting integrated string successfully completed the construction of 8-stage fracturing and 8-stage supplementary perforation of coalbed methane U-shaped horizontal well. The perforation time of each section is more than 15min, and fully displace the backflow pulverized coal, after three years of operation, the gas production still reaches more than 3500m3/d, it shows that the optimized process has achieved the transformation effect of broken soft and low permeability coal seams. Compared with coiled tubing staged fracturing technology,The single-stage fracturing operation cost through hydraulic jet fracturing by dragging tubing has been reduced by 28.5%.

The underground water supply system of coal mine was the lifeline of coal mine safety production. The prediction of water flow of water supply network was the basis of water supply system optimization dispatching. The importance of prediction has important influence on water supply dispatching. This paper proposes a method of flow prediction of underground coal mine water supply network that integrates multi-modal data features. Different from previous methods, deep learning method realizes the integration of multiple data related to spatial topology structure of underground pipe network, historical time dependence, actual underground production conditions and cycle. Specifically, The graph convolutional neural network adding spatial attention mechanism is used to obtain the spatial topological relationship of the monitoring points of underground pipe network, and then the gated circulation unit in the cyclic neural network is used to obtain the time dependence of the monitoring points, and the final prediction results are formed by integrating the production rules of coal mine with the flow data of different periods. Through the actual data experiment of a mine in Shaanxi Province, The results show that compared with SVM, LSTM, STGCN and other methods, the proposed method can more accurately predict the future trend of downhole flow, and the prediction deviation is reduced by 9.3%, 6.84% and 3.65%, respectively.

With the optimization of the final mining limit of open-pit mine, the planning of material flow, stripping engineering deduction, propose and study the dynamic design and optimization of medium and long term schedule, need to open pit mine existing 3d geological model of the multistage discrete refinement, and the traditional segmentation and Boolean operation of the ground mode can hardly meet the needs of the multilevel discretization.. In this paper, the mining block model and mining model are defined, and a based on ternary DEM open-pit coal mine closed shell envelope voxel modeling method, model of coal and rock ternary DEM refers to the top, bottom and side DEM, ternary DEM after curing the coal and rock can generate the corresponding closed shell envelope voxel model. The model between entity model and the block model, can very good protection to calculate quantity accuracy, have higher Boolean operation efficiency at the same time, can be the reality that decide a dot, the size and structure of the directional cutting, on the basis of the traditional calculate to mould, through specific structure definition, rich stripping process and process parameters, such as technical indicators attribute, customize the exclusive mining model, It can better serve the demand of dynamic optimization problem of open pit mine.

Raise shaft drilling method is one of the key technologies of rapid mechanized construction of coal mine shaft. Raise shaft drilling technology is widely used in the field of large-diameter coal mine ventilation shaft engineering. Its diameter is usually greater than 5m, which brings challenges to safe construction. How to accurately pre evaluate the stability of shaft structure in the process of raise shaft reaming according to the geological data of well inspection hole is the key problem to determine the safety and engineering quality of raise shaft construction. In order to solve this problem, an evaluation method of shaft structure stability considering the technological characteristics of raise boring method is proposed. In view of the large-diameter raise shaft project represented by the ventilation shaft, the determination of the surrounding rock self stability is the key factor. Based on the strength reduction method, a quantitative evaluation method of the surrounding rock self stability ability of the shaft wall with the surrounding rock stability coefficient as the core is proposed, and the surrounding rock stability coefficient under the extreme self stability state of the surrounding rock is determined by numerical simulation. Finally, taking the return air underground shaft project of lijiahao coal mine as the research object, the local instability risk assessment opinions are put forward, and the accuracy of the assessment is verified based on the engineering practice. The results show that the assessment conclusion is consistent with the actual results.

Gob-side entry driving with small coal pillar is an important way to realize high recovery mining in extra thick coal seam. But large space and high strength mining of extremely thick coal seam leads to high intensity mine pressure behavior, meanwhile, the gob-side roadway is in plastic zone of whole coal. So it is difficult to control surrounding rock. In order to solve the supporting Problem of gob-side roadway in large scale plastic zone of whole coal using anchor-net –cable, taking 8204-2 Small Coal Pillar working face of Tashan coal mine as engineering background. This paper revealed the supporting mechanism of bolt and anchor cable for large-scale plastic zone of gob-side roadway: Bolt support acts on shallow secondary crushing area of surrounding rock, forming shallow continuous load-bearing structure; anchor cable acts on the stable surrounding rock in deep three-way stress state to form a larger range of continuous stable bearing structure. Based on this, the calculation method of effective length of bolt and anchor cable is further clarified. And the synergetic control technology of surrounding rock for gob-side entry driving in extremely thick coal seam was formed, which based on the support of anchor-mesh-cable with high pre-tightening force and high strength, and using abrasive water jet cutting roof pressure relief in hard roof, large diameter borehole pressure relief in roadway side, bottom plate pressure relief groove pressure relief as auxiliary. The engineering application results show that, the maximum deformation of surrounding rock of test roadway is less than 700 mm, which can meet the use requirements.

Abstract: Based on the conditions of 22406 fully mechanized working face in Bulianda Coal mine, the paper studies the scientificness and rationality of adopting the active advancing support of anchor cable in the main roadway of the working face by combining theoretical analysis and field measurement. Based on the supporting model of solid coal roadway on both sides and the calculation and analysis of relevant parameters, it can be seen that the advancing support form of "row distance of 3m, 2 sets per row" between the special anchor cable designed for the main tunnel roof and the original support meets the requirements of the working face advanced support. Through the force monitoring of the anchor rod (cable) in the advancing support section of the main roadway, it can be seen that the influence range of the advancing abutment pressure is about 42m, and advancing pressure is larger in the range of 10 ~ 26m away from the working face, and the statistical stress concentration coefficient is 1.23 ~ 1.5. According to the displacement monitoring of the surrounding rock surface, it can be seen that the main roadway begins to deform under the influence of mining at about 35m from the working face. During the mining process, the maximum subsidence of the roof is 12mm, the floor heave is 16mm, the forward side heave is 29mm, the secondary side heave is 25mm, the maximum separation of layer is 7mm in the deep part of the roof, and the maximum separation of layer is 3mm in the shallow part. The above research results show that the surrounding rock can be effectively controlled and the field application effect is good by using the anchor cable reinforcement advancing support method. The popularization and application of this technology in Shendong mining area is of great significance in realizing unmanned and less unmanned working face and reducing labor intensity of workers.

Aiming at the problems of difficult parallel operation of excavation and support and imbalance of time proportion in heading face, in order to realize parallel operation and rapid support, a new temporary support device is designed, which has the characteristics of adjustable size, rapid response and timely support. The method of theoretical analysis and numerical simulation is used to study ; the structure design of the device is introduced. Taking the comprehensive excavation construction technology of a mine as an example, the process optimization is carried out, and a construction technology of partition parallel operation is proposed theoretically. Through the mechanical model of simply supported rock beam at both ends of the roof, the mechanism of temporary support of the device is analyzed. The supporting performance of the device is analyzed by structural statics. The results show that when the roof looseness range of the roadway is 0 ~ 3.30 m, the load required for the device support is 158.4 kN ; the maximum equivalent stress obtained by simulation is 57.37 MPa. At the junction of the lower end of the top beam of the device and the position of the ear seat, the maximum displacement appears in the middle of the upper end of the middle beam, which is 0.30 mm. The structural design of the device can meet the support requirements. This study can provide a useful reference for the parallel operation of rapid excavation, efficient support and safe production.

In view of the strong mine pressure problems such as large shrinkage of 'large period' weighting support column, high stress concentration coefficient of coal pillar and poor stability under the condition of near-shallow buried multi-layer thick and hard roof in Yushen mining area, numerical calculation, microseismic and coal body stress monitoring are used to analyze and study the fracture movement of overburden rock and the pressure law of working face. The results show that: (1) In the fracture movement of overburden rock, the large 'vertical separation space' and 'bottom-up' sequential alternate collapse of multi-layer thick and hard roof breed the space-time basis of 'high + low-level combined fracture' of roof. The 'high and low layer roof combination fracture' is the key inducement of 'large period' weighting enhancement; at the same time, the spatial and temporal evolution of coal pillar stress is controlled by the fracture and collapse of multi-layer thick and hard roof. (2) In terms of mine pressure appearance, the average shrinkage under the 'large cycle' pillar of the working face can reach 945mm, the continuous distance is 12.10m, and it can be composed of 2~5 consecutive strong pressures; the stress concentration factor of roadway coal pillar reaches 1.80 ~ 2.30, and the influence range is 126 m in front of the working face to 471.3m in the rear, which has obvious characteristics of 'high strength, large range and long rising period'. Aiming at the prevention and control of strong mine pressure under this condition, the technical ideas of 'weakening low roof, optimizing fracture structure' and 'weakening high roof, changing fracture sequence' are put forward respectively, and good application results are obtained.

The main roadway in the 2502 mining area of Yanbei Coal Mine is an isolated island coal pillar with high stress concentration. Due to the thick thickness of the coal seam, large diameter drilling for pressure relief cannot achieve good anti erosion effect. To address this issue, a technical method for hydraulic expansion and pressure relief in coal seams has been proposed. Through theoretical analysis, the pressure relief mechanism of water jet coal breaking and hole expansion was studied, and the main technical parameters of hydraulic hole expansion were determined. The pressure relief mode of segmented hole expansion in the borehole was analyzed using numerical simulation, and corresponding supporting equipment was developed and on-site tests were conducted. Through research, it has been found that hydraulic expansion expands the pressure relief range of a single hole by increasing the drilling diameter. The use of double-layer high-pressure drill pipes can achieve integrated pressure relief of coal drilling and cutting, improving pressure relief efficiency. The on-site test results show that when the water pressure of coal seam hydraulic expansion is 40MPa and different nozzle combinations are used, the expansion radius can reach 0.35m~0.5m, and the amount of drilling debris in the expansion area is significantly reduced. The results indicate that hydraulic expansion can significantly reduce stress concentration in the coal body, achieving the goal of preventing and controlling rock burst.

Hujierte mining area in the border area between Mongolia and Shaanxi is a new developing coal base, which has some problems, such as unclear hydrogeological conditions and frequent water damage problems. By analyzing the geological and hydrogeological characteristics of the roof of the first mining face of four mines in hujierte mining area, and the change and difference of water inflow during mining, we hoped to find out the hydrogeological conditions under the disturbance in the initial stage of coal mining in this mining area. It provided a scientific basis for water disaster prevention and control in Inner Mongolia and Shaanxi mining areas. The results showed that under the control of sedimentary cycle, and the action of river rejuvenation in the early Zhiluo formation, a relatively strong erosion was formed on the Yan'an formation, forming a regional aquifer with strong water abundance (i.e. qilizhen sandstone), which was the main water filled aquifer in the first mining coal seam. Muduchaideng and the south of Menkeqing were located in the middle of guzhiluo river. The lithology was mainly medium and coarse-grained sandstone and conglomerate. The riverbed width was large. It cutted deeply into Yan'an formation. The aquifer thickness was generally greater than 40m. The initial water inflow of underground boreholes was generally greater than 100m3/h, and the initial water pressure was as high as 6.0MPa. Generally, it was characterized by strong water yield and high confined water pressure. Hulusu, Bayangaole and the north of menkeqing were located on banks of the ancient riverbed of Zhiluo river. The aquifer thickness was generally 20~30m, and the initial water inflow of underground boreholes was basically less than 30m3/h. The water inflow of the first working face of the four mines gradually increased with the mining of the working face. The maximum water inflow of the first working face of Hulusu and Bayangaole mines were 645.0m3/h and 494.0m3/h respectively, and there were water abundance differences in different areas of the sandstone aquifer in Qilizhen, resulting in a stepped increase in water inflow with great fluctuation, It was consistent with the characteristics of thin sandstone aquifer and weak water yield in Qili town. The maximum water inflow of the first mining face of menkeqing and Mudu Chaideng mines were 1372.0m3/h and 938.0m3/h respectively, and the overall water yield of the sandstone aquifer in Qili town was strong and uniform. The increase of water inflow showed a steady increase trend with small fluctuation, which was consistent with the characteristics of large thickness and strong water yield of the sandstone aquifer in Qili town on the roof of this area.

Abstract: In view of the current evaluation of grouting effect in working face threatened by floor confined water and dynamic monitoring of the dynamic development of cracks in abnormal areas in working face during mining, the electrical intelligent monitoring technology is adopted to carry out grouting effect monitoring test in the low resistance abnormal area of 61304 working face in Tangshan Jiahui Coal Mine and real-time monitoring of coal seam floor in the process of mining. By monitoring the change of rock resistivity, the dynamic diffusion trend of grouting fluid and the dynamic development process of mining-induced fissure were successfully captured, and the dynamic development of water channel was timely warned. The research shows that the intelligent monitoring technology of electric method can clearly monitor the dynamic development process of the water channel and distinguish whether the water channel is connected to the aquifer. It is a new technology for monitoring the water inrush of floor in pressure mining working face, providing technical guidance for the mining of floor pressure working face and ensuring the safety of coal mine production.

In order to solve the problem of spatiotemporal interference between mine filling and coal mining, safe and efficient filling and mining of mines can be realized. Combined with the production system and mining conditions of Lijiagou mine, the non-cemented paste filling technology of floor drag pipe between the goaf was developed. In order to ensure the feasibility and basis of this technology, a physical model of non-cemented paste interframe floor drag pipe filling goaf was established, and non-cemented paste filling materials were prepared by using gangue and fly ash as aggregates, and the interaction between maximum particle size and mass concentration on the flow characteristics of slurry goaf was analyzed. The results show that: (1) the filling amount of slurry is mainly affected by the particle size of gangue, and the mass concentration mainly affects the diffusion rate of slurry in the goaf; (2) With the increase of slurry filling, the voids in the goaf gradually tend to be saturated, and the permeation mode shows a hemispherical diffusion distribution with the nozzle as the spherical center; (3) The simulation test revealed the mechanism of slurry flow diffusion and obstruction in the goaf area; (4) The sections are cut sequentially along the pipeline trend, and the gangue gradation and mass concentration in the slurry have obvious separability.

The No.9 coal seam of Yunjialing Mine is overlying thick and hard rock strata, and the mine pressure in the stope is strong. It is difficult to control the surrounding rock by using the traditional gob-side entry retaining method. Based on the transportation roadway of 19103 working face in Yunjialing Mine, the mechanical equilibrium conditions of thick and hard immediate roof of gob-side entry retaining with roof cutting are analyzed, and it is concluded that the support resistance of no less than 1046kN should be provided beside the roadway. The numerical simulation method was used to compare the deformation and stress of surrounding rock and the distribution of plastic zone of gob-side entry retaining with and without roof cutting under the condition of thick and hard direct roof. The results show that the roof of goaf is more likely to collapse after roof cutting. The subsidence of the roof of the retaining roadway is only 28.2 % of that without roof cutting in the same period. After roof cutting, the vertical stress of the roof on the side of the retaining roadway becomes smaller, the horizontal stress increases and the plastic zone of the surrounding rock transfers to the deep part of the roof and floor. It is revealed that the mechanism of pre-splitting roof cutting pressure relief is to block the transmission of dynamic pressure in the working face and induce the roof of the goaf to fall in ad-vance to meet the roof pressure. The reason for the increase of horizontal stress is the result of the deformation of the long and short ' cantilever beam ' formed on both sides of the slit. The roof control idea for gob-side entry retaining with thick and hard immediate roof is proposed as centralized support of the cutting end, appropriate pressure relief and formation of “combined can-tilever beam”. The comprehensive support technology of long and short anchor cable, single hydraulic prop and yielding U steel beam is adopted, and the sealing measures of hanging net shotcrete are adopted. The field industrial test results are good, the peak stress of the anchor cable of the roadway roof after cutting the roof is about 350kN, the roadway section is 2.95m×2.44m (width × height) after the surrounding rock is stable, and the specifications meet the conditions of secondary reuse. The technology has been successfully applied in the subsequent No.9 coal face in Yunjialing Mine.

The hard roof is an important factor affecting the impact risk of the working face, and blasting technology is often used in practice to pre-split and relieve pressure on the working face roof. This article takes the 7202 working face with a hard roof above the 3rd coal seam of a certain mine as the object, and uses methods such as theoretical analysis, numerical simulation, and industrial experiments to study the stress evolution of surrounding rock and the law of mining tremors under different blasting heights, single and double roadway roof blasting in the working face. The results show that when using single or double roadway blasting for low level sub-key stratum, the higher the blasting height, the lower the peak stress of the surrounding rock in the roadway, and the pressure relief effect is positively correlated with the blasting height. However, when using double roadway blasting and increasing the blasting height to more than 6 times the mining height, there will be a phenomenon of stress increase in the central area of the working face, and the shorter the working face, the more obvious the stress increase. During the initial mining stage of the 7202 working face, when single roadway roof blasting with a height of 3 times the mining height was carried out, the microseisms were mostly concentrated in the roadway area, and the pressure relief effect was moderate. After changing to double roadway roof blasting and increasing the blasting height to 6 times the mining height, the microseisms were mostly concentrated in the central area of the working face, without the occurrence of high-energy mining tremors. The number of stress monitoring warnings was also significantly reduced, and the pressure relief effect in the roadway area was good.

The disaster of hard roof perplexes more than half of the coal seam mining in our country. In view of the difficulty of disaster prevention and control of hard roof in coal seam mining, many scholars have carried out extensive research on roof hydraulic fracturing monitoring and evaluation technology, but there is a lack of in-depth summary of its research and application status. Based on this, this paper combs the common hard roof hydraulic fracturing monitoring methods, the application of microseismic monitoring in hydraulic fracturing hard roof, and discusses the hydraulic fracturing effect evaluation technology. The research shows that microseismic monitoring technology is widely used in the research of hydraulic fracturing weakening technology of hard roof because of its advantages of non-destructive testing and spatial three-dimensional monitoring. the system layout mainly includes surface monitoring, downhole monitoring and joint monitoring. On this basis, the evaluation technology of hydraulic fracturing effect of hard roof is discussed, and some suggestions are put forward to strengthen the research on the influence of joint occurrence, develop transparent monitoring technology and establish fine evaluation technology. The research results have important guiding significance for optimizing hydraulic fracturing engineering design of hard roof and improving the control effect of hydraulic fracturing of hard roof.

Aiming at the difficulty of pre-drainage gas in low permeability and high gas coal seam, the technology of directional hydraulic fracturing of coal seam with guide groove is proposed. The distribution of plastic zone after reaming in coal seam is calculated by theoretical derivation, and the initiation and propagation of hydraulic fractures in coal seam of cross-seam drilling are analyzed to reveal the mechanical mechanism of directional hydraulic fracturing of coal seam with guide groove. The permeability-increasing equipment for directional hydraulic fracturing of coal seam with guide groove was developed and applied in Shanxi Zhongxing Coal Mine. The results show that after the water jet method is used to expand the coal seam section of the cross-layer borehole, an approximately cylindrical hole is generated in the coal body. The radius of the plastic zone of the surrounding rock of the cross-layer borehole is positively related to the radius of the borehole. Drilling reaming is an effective method to increase the range of the plastic zone, which has a significant role in promoting the development of cracks, thereby improving the gas extraction effect. A complete set of equipment for directional hydraulic fracturing and outburst prevention of guide groove is developed. The main components are mobile high-pressure hydraulic pumping station, nozzle, nozzle, orifice blowout preventer, spiral assisted slag discharge water jet high-pressure drill pipe and high-pressure rotary joint, combined with remote monitoring and control of downhole hydraulic operation. The field monitoring results show that the average gas concentration and the mixing amount of gas drainage are increased to 2.75 times and 1.81 times of that of the conventional hole by the method of permeability-increasing drilling, which indicates that the permeability-increasing effect of directional hydraulic fracturing with guide groove is remarkable. The research results provide a new technical approach for pre-drainage gas in low permeability and high gas coal seam.

Through the analysis of monitoring data, the fault diagnosis technology of dry type transformer can extract signal feature, fault diagnosis, state assessment and life prediction, improve the safety of dry type transformer in underground operation, and reduce the loss caused by the fault. This paper introduces the research status of signal feature extraction method (frequency response method, wavelet transform method, stacked autoencoder), fault diagnosis method (BP neural network, support vector machine, Bayesian network), condition assessment and life prediction method (cross entropy combination prediction method, grey theory, analytic hierarchy process), and compares several methods. Finally, the dry type transformer fault diagnosis technology is prospected.

Taking the south third plate area of Duelping coal mine in Taiyuan Xishan mining area as the study area, FLAC3D software was used to establish numerical model to analyze the evolution of surface subsidence coefficient after repeated mining of 2# and 3# coal seams in this area, and the results of numerical simulation experiments show that: the results of the subsidence prediction coincide well with the original results, and the subsidence coefficient shows a tendency to increase with the increase of the number of repeated mining, and it is 1.1 times as high as the full height of one-time mining in the 2# coal seam, and 1.27 times as high as the full height of one-time mining when continuing to mine the lower 3# coal seam. The subsidence coefficient is 1.1 times higher than the total height of one-time mining, and the subsidence coefficient is 1.27 times higher than the subsidence coefficient of the 2# coal seam when the lower 3# coal seam is continued to be mined. The results of the study provide a basis for the prevention and control of surface subsidence and the protection of features under repeated mining of multiple coal seams, and also provide a basic reference for the study of digital geomorphologic evolution of coal mining subsidence areas.

Coal mine gas is one of the causes of major disasters. Low extraction concentration and poor effect are common pain points in engineering practice. Aiming at the technical problems of low average concentration and short duration of gas extraction in coal mine and the field requirements obtained from engineering practice, interface modification methods such as mechanical modification method and organic activation modification method were selected, and bentonite as the base material was used to improve water retention, stability and thixotropy, and liquid phase sealing materials for gas drilling were developed. The idea of "liquid sealing gas" is adopted to realize full - cycle thixotropic sealing of nascent cracks. The application results of Renlou Coal Mine show that the new material has good plugging effect, and the average extraction concentration is 41.66%, which is 15.27% higher than that of the traditional material. Concentration attenuation coefficient decreased by 48%; Slurry lifting coefficient increased by 22%; Can realize waste hole utilization. The new type of sealing material will have good application value in the field of gas extraction and disaster control in coal mine.

In order to predict the expansion characteristics of Geldart A particles, we investigated the correlation between the composition of the bubble and emulsion phases in the fluidization process and the operational factors, constructed data sets of operating gas velocity, static bed height and bed expansion height by bed collapse experiments, performed statistical distribution and correlation analysis, and then successfully simulated the nonlinear relationship between expansion height and influencing variables by using GBDT model with optimal hyperparameters, and finally, performed sensitivity analysis of the characteristic variables. The results show that, with the gradual increase of gas velocity, the expansion of emulsified phase and bubble phase shows a pattern of increasing and slightly decreasing first. For different initial bed heights and bed expansion heights, the composition of the bubble phase is not affected by their changes and the composition ratio is relatively stable. It is obtained that the importance score of operating air velocity is 0.68, which is the most sensitive variable for the expansion height. Compared to the operating gas velocity, the importance score of the static bed height is 0.32, and the influence of the static bed height on the bed expansion is smaller. In addition, from the partial correlation analysis, it can be seen that the dependence of bed expansion height on operating gas velocity has a certain sensitivity interval.

In order to relieve the pressure of waste PVC treatment and recover hydrocarbon resources, the waste PVC was added to pulverized coal to prepare waste PVC-coal slurry. The morphorlogy and specific surface area of the prepared waste PVC-coal slurry were determined using SEM-EDX and BET, repectively. The influencing mehcainnsms of the added PVC in slurry performance were investigated. The combustion characteristic index and kinetic parameters of raw coal slurry and waste PVC-coal slurry were evaluated by thermoweight analysis method and Coats-Redfern integration method. The results show that the waste PVC can improve the slurry concentration but reduce the stability. Addition of the waste PVC exhibits a synergistic effect on coal slurry combustion. When the amount of waste PVC added is 5%, the positive synergistic effect is the strongest, the burnout rate of coal slurry is the largest, the comprehensive combustion performance is the best, and the apparent activation energy is the largest.

In order to clarify the current situation of soil fertility in Fushun West Open-pit Mine, this paper takes Fushun West Open-pit Mine as the research object, considers the main physical and chemical properties of the soil, selects soil bulk density, soil moisture content, soil porosity, soil mechanical composition, pH value, organic matter, total nitrogen, total phosphorus, total potassium, alkali-hydrolyzable nitrogen, available potassium, and available phosphorus as the soil fertility evaluation indicators, and uses the modified Nemero index method to comprehensively evaluate the soil in the mining area. The evaluation results showed that the comprehensive index of soil nutrients in the sample plots of the northern slope area, the southern slope deformation area and the western slope restoration area was between 0.4 and 0.6, and the soil nutrients were graded as Grade III, and the soil nutrient level was average; The comprehensive index of soil nutrients in the sample plots of Dongbang mining area is between 0.2 and 0.4, and the nutrient grade is II, and the soil nutrient level is relatively poor. The order of size is the sample plot of the landslide area in the north side>the deformation area in the south side>the sample plot of the repair area in the west side>the sample plot of the mining area in the east side. It can be seen that the soil nutrient in the east side of the west open pit is relatively deficient, the soil in the west side is slightly deficient, and the soil nutrient in the north side and the south side is relatively rich.

The integrated energy system can coordinate the planning of multiple energy sources, improve the absorptive capacity of renewable energy, so as to realize the low-carbon and efficient operation of the system. Based on this, this thesis proposes a comprehensive energy system integrating photovoltaic power generation system, heat storage water tank and internal combustion engine. Considering the constraints of energy balance in three forms of cold, heat and electricity, the genetic algorithm is used to establish the optimization model of comprehensive energy system planning with the minimum annual total cost as the optimization goal, and the annual total carbon emissions and annual total primary energy consumption as the evaluation indicators. The results show that the annual total cost saving rate, annual carbon dioxide emission reduction rate and annual primary energy saving rate of the proposed integrated energy system are 30.67%, 33.26% and 8.93% respectively, compared with the separated production system. In addition, the photovoltaic power generation system in the integrated energy system bears 14.58% of the annual user electric load, effectively improving the economy and energy efficiency of the system.

The study of miners' unsafe behavior is a classic problem in the field of safety management. The existing literature mostly explains the mechanism of unsafe behavior from the perspective of human factors engineering and behavioral economics, but no literature pays attention to the decision-making mechanism of miners' unsafe behavior in the state of "without careful consideration". This study constructs a dual processing mechanism explanation model of miners' unsafe behavior based on the dual system theory. The questionnaire survey method was used to mobilize miners to make threat assessment on 25 kinds of unsafe behaviors in the state of system 2, that is, thoughtful. The results showed that for all unsafe behaviors, the proportion of respondents who judged such behaviors as "frequent occurrence" was much higher than the proportion of people who made "low threat assessment", indicating that miners did use the decision-making mechanism of system 1, that is, "not thoughtful", to implement unsafe behaviors in the production process. On this basis, this paper analyzes the influencing factors of miners' behavior decision-making by using system 1. Past behavior, imitation effect, time pressure and cognitive motivation are the main influencing factors of the processing mechanism of system 1, and accordingly puts forward the control strategies for unsafe behaviors under the state of system 1.

In order to fully explore the key text knowledge of coal mine safety hidden danger and help the safety management personnel of coal mine enterprises to better carry out hidden danger investigation and management work, a named entity recognition method based on pre-training language model is proposed. Firstly, entity categories of coal mine safety hidden danger were defined according to the new version of Coal Mine Safety Regulations and Criteria for Determining Potential Major Accidents in Coal Mines, and 7 entity categories and 15 entity labels were constructed using BIO labeling strategy. Then, the collected data of coal mine hidden danger investigation are preprocessed, and relevant entities are manually marked by experts in the field of coal mine safety, and 1500 standard data sets of named entities for coal mine safety hidden danger are obtained. Finally, the ERNIE pre-training model is used to represent the text word vector of coal mine safety hidden danger, and the BiGRU structure is used to extract the context semantic features and the CRF model is used to decode the entity label, and complete the research on the named entity recognition of coal mine safety hidden danger. The experimental results show that: The accuracy rate, recall rate and F1 value of ERNIE-BiGRU-CRF model on sequence labeling tasks are 56.69%, 69.23% and 62.34%, which are respectively 6.85%, 13.74% and 9.83% higher than baseline model of BiLSTM-CRF. And there is little difference between the entity extraction result and the actual label result. In addition, the ablation experiment also verified that BiGRU layer could better capture semantic dependencies of text context for coal mine safety hidden danger and CRF layer could further optimize label sequence. It can be seen that the named entity recognition model based on the ERNIE-BiGRU-CRF algorithm structure has a good entity recognition result in the text information extraction of coal mine safety hidden danger, which provides convenience for the accomplishment of intelligent management of coal mine safety hidden danger.

Aiming at the problems of scraper bending and fracture, sprocket sealing failure, and other issues in the use of the Shendong 7-meter high mining face slot transfer machine, by analyzing the failure characteristics of scraper and sprocket components and the stress status of components, measures such as upgrading the chain, increasing the scraper section and sprocket shaft diameter, optimizing the chain center distance, etc. were taken to comprehensively improve the stress status of scraper and sprocket components, and increase the scraper strength by 1.7 times, The deflection of the sprocket shaft at the bearing support area is reduced to 1/8, significantly improving the performance of the components. Component universality should be fully considered during equipment renovation,drive frame and pan can be used directly to reduce renovation cost. By renovation to imported equipment, experiences are accumulated, and development of domestic coal mining equipment is promoted.

Summarized the models, quantities, and driving control technologies of auxiliary transportation vehicles powered by lithium-ion batteries in the Shendong mining area; The main measures for electrification of auxiliary transportation vehicles are to increase the capacity of individual batteries, build intelligent charging and swapping chambers in coal mines, and establish passive charging systems for electric vehicles; The energy consumption cost of explosion-proof electric auxiliary transportation vehicles per 100 kilometers is only 6.5% of that of diesel vehicles of the same type. The modules in the architecture of the auxiliary transportation vehicle management system are discussed, including mine map, vehicle management, mileage statistics, driver management, equipment management, safety management, system management, etc. Based on the positioning system for underground personnel and vehicles, the underground 4G or 5G network and tunnel base station are used to transmit to each mine ground dispatch room, and transmitted to the big data center through optical fiber, achieving digital vehicle supervision and making vehicle use and dispatch more convenient. Analyzed intelligent technologies such as on-board auxiliary safety driving system, start warning system, intelligent induction automatic shutdown device, neutral start protection device, wireless line of sight remote control for auxiliary transportation vehicles; Using LiDAR and camera to scan and model the roadway, providing a "map" for unmanned vehicles, and using millimeter wave radar technology and machine vision technology to achieve precise positioning of auxiliary transportation vehicles underground, achieving the normalized operation ability of unmanned driving. The electrification, digital supervision, and intelligence of Shendong auxiliary transportation vehicles have greatly improved the safety and efficiency of auxiliary transportation. The next step is to couple and design the auxiliary transportation vehicle information with comprehensive mining information, excavation information, personnel information, production indicators, safety information, etc. to form an integrated control platform and improve the level of intelligent construction in coal mines.