To determine the reasonable staggered distance of the close coal seam group and reveal the evolution law of overburden fracture, taking the 02 and 2 coal seams group as the research object, the theoretical model was used to calculate the damage depth of the upper coal seam floor and the staggered distance. A numerical model was established to analyze the distribution of interlayer rock abutment stress under the conditions of 35 m, 40 m, and 45 m staggered distances, and similar simulation experiments were used to study the characteristics of overburden fracture evolution. The results show that the abutment stress of the upper coal seam is transmitted to the floor rock through the working face, and the damage depth is 5.45 m; The maximum influence range of support pressure in floor rock behind working face is close to 38 m. The interlayer rock abutment pressure experienced two peaks. When the staggered distance is 40 m, both peaks of support pressure in lower coal seam working face are small, and the reasonable staggered distance is determined to be 40 m; The initial collapse step distance and periodic collapse step distance of upper working face roof are 40 m and 15-20 m respectively, while those of lower working face main roof are significantly increased to 80 m and 20-30 m. The research results can provide reference for safe and efficient mining of close coal seam group.

Abstract: Aiming at the problem of how to remove hilt quickly, economically and safely in high mining height working face, three design schemes of removing hilt technology were proposed, including advance stopping mining method, direct penetration method and filling penetration method, which combined with the characteristics of easy coal wall spalling, giant facilities, severe mine pressure appearance and large section of withdrawal channel. The advance stopping mining method means that the last half of working face to be remove is ended mining in advance, and then the equipment recovery is completed by the current construction withdrawal channel. The direct penetration method is used to strengthen the support of the crossheading roadway in advance at the hilt of working face, and then the equipment recovery is completed from the withdrawal channel after the last half of working face is directly penetrated. The filling penetration method fills the crossheading roadway in advance at the hilt of working face, then the equipment recovery is completed after the working face penetration and the filling material recovery. According to the general situation of removing hilt engineering in 4321 high mining height working face of a mine, the value coefficient of three technical schemes is analyzed and calculated by using value engineering theory. The results show that the value coefficient of filling penetration method is higher than other two methods, which is the optimal technical scheme for the construction of removing hilt in this working face. From the engineering practice of removing hilt in 4321 working face, the filling penetration method has the advantages of simple construction technology, short construction period, high resource recovery rate and high safety guarantee degree, which can realize the purpose of safe, efficient and fast removing hilt in high mining height working face.

Based on the geological conditions of gas in the ultra-thick coal seam under the mining of the upper protective layer, comprehensive theoretical analysis, numerical simulation, engineering practice and other methods were used to study the distribution characteristics of lateral stress in the goaf, the variation law of outburst risk prediction indicators, and the reasonable location of the goaf roadway. The results indicate that there is a stress recovery effect in the fractured rock mass after the mining of the upper protective layer, and after the stress recovery, the peak lateral stress in the goaf will move towards the direction of the goaf; Based on the test results of coal outburst prediction indicators at different distances from the side of the goaf, sufficient pressure relief discharge area, effective pressure relief discharge area, and hazardous area were divided. Combined with engineering analogy, numerical simulation results, and the need to isolate gas in the goaf, a width of 5~7m was determined for the coal pillar along the goaf; After adjustment, the maximum values of outburst prediction indicators and return air gas concentration during tunnel excavation were 0.16mL/(g·min1/2) and 0.22%, respectively, with a decrease of 66% and 35.3% compared to before adjustment, ensuring the safety of roadway excavation and verifying the rationality of retaining coal pillars along the goaf.

This article designs an energy-saving speed control system for a belt conveyor based on machine vision technology to address the problem of energy waste caused by the mismatch between the actual operating speed of the underground belt conveyor and the changes in belt load. Machine vision technology is used to detect the load of the belt conveyor in real-time, which regulates the output frequency of the frequency converter to adjust the operating speed of the belt conveyor. The experimental results show that the load detection results of the system are reliable, and the actual operating speed of the belt conveyor can match the coal flow rate. The energy consumption is reduced by about 31.25% in 24 hours, realizing the autonomous perception and energy-saving operation of the coal flow transportation system.

In order to meet the development needs of intelligent integrated liquid supply in underground coal mines, an integrated liquid supply control system based on cloud-edge-end architecture was designed, aiming at the problems that the existing liquid supply control system could not meet the increasing demand for data communication capabilities, insufficient data processing and work coordination capabilities, and low degree of autonomous decision-making. The system uses the field industrial bus and industrial Ethernet composite communication technology to solve the problem of insufficient data communication ability of the existing liquid supply control system. Cloud-edge-end architecture is adopted to reduce the data transmission delay and save the resources of the central computing unit. The control effect of pressure flow of the system is optimized by the frequency conversion-unloading linkage control algorithm and the step unloading algorithm of pump station group. This paper introduces the overall system architecture, hardware design scheme and software design scheme, and completes the underground industrial test. The research results show that the system can improve the communication bandwidth to meet the needs of use, the design structure is reasonable, the pressure fluctuation range is reduced, and the intelligent development of integrated liquid supply system of fully mechanized mining face in coal mine is promoted.

This paper gives full play to the advantages of one main body integrated development in the Xinjie Taigemiao mining area, and combines the location of each mine field in the mining area. Adhering to the development concept of "intensive, sharing, green, economic and efficient", we abandoned the idea of building four mine type coal preparation plants or four Wells jointly building one group coal preparation plant, and chose the layout of two Wells jointly building two group coal preparation plants. It greatly saves the land area, improves the use efficiency of infrastructure facilities, realizes the measures of energy saving and consumption reduction, reduces the construction investment and operating costs, improves the efficiency of all personnel and design efficiency, and has a good reference significance for the layout of group coal preparation plants with similar conditions.

Composite regenerated roof is a common object in deep and close distance coal seam mining, and the stability control of broken structure roof is the key to affecting the efficient mining of the lower layer. In order to improve the safety and mining efficiency of the composite regenerated roof working face, experiments were carried out on the coal body water injection solidification, roof grouting reinforcement, and pipe joint anchor rod roof reinforcement at the No.16-17-31020 composite regenerated roof working face of Pingmei No. 12 Mine. The mining pressure law of the composite regenerated roof working face was explored, and the support effect of reinforcement measures was evaluated. The research results indicate that after the implementation of reinforcement measures, the integrity of the working face is significantly improved, reducing the risk of accidents such as roof caving and frame compression. The average pressure step increased from 22.15 m to 29.92 m, and the roof pressure decreased from 25-31 MPa to 19-26 MPa. The amount of roof subsidence has been reduced by 50.4%, ensuring normal and safe mining of the working face, while the mining rate has increased by 16.7%. The coal solidification and roof strengthening measures have achieved good benefits, which can provide reference significance for the same type of composite regenerated roof working face.

In order to solve the difficult problem of supporting the roadway under the laminated deteriorated broken roof, the deformation and damage law of the roof slab under the laminated deterioration of the roadway was studied, and the corresponding support countermeasures were proposed and applied in the field, using the east four belt extension road of Xinzhi coal mine as the engineering background. Using the interface unit in FLAC3D, the roof model of the laminated roadway was established, the deformation and damage characteristics of the broken roof slab under the influence of laminae were analyzed, and the deformation law of the roadway surrounding rock with different support schemes was compared. For the laminated roof slab, the high prestressed bolt can fully improve the self-bearing capacity of the roof slab, and then reduce the bolt support density, which can control the deformation of the roadway surrounding rock and also improve the digging speed. Finally, the proposed support measures were applied to the site, and the monitoring data showed that the support measures can ensure the stability of the roadway surrounding rock and help to improve the roadway digging speed, and provide a reference for similar laminar deterioration of the roadway support under the broken roof.

In view of the problems of broken peripheral rock of the roadway under the top coal damage area, which leads to difficulties in expanding the gangs, Hanzui Coal Industry took the 32101 working face cutting eye as the research object, analysed the destabilisation mechanism of the roadway expanding the gangs in the top coal damage area; and put forward the control technology of the peripheral rock of the top plate pre-grouting, which is based on the formation of the slurry stopping curtain, and then constructed a regenerated top plate by grouting. Through numerical simulation to verify the reinforcement effect, the results show that the plastic zone range of the roadway is significantly reduced after grouting; the field application results show that: after adopting the roof pre-grouting reinforcement measures, the maximum amount of the top and bottom plates of the peripheral rock of the cutting eye of the working face of 32101 was 160 mm, and the maximum amount of the two gangs was 129 mm, which is a good effect of the reinforcement of the peripheral rock.

By establishing a grouting station and drilling holes in the separation zone for grouting, the grouting in separated-bed can enable the slurry to fill the separation space between the rock layers, limit the movement and deformation of the overlying rock layers and control surface subsidence. This article selects the working face 11-3101 of Mengkeqing Coal Mine in Inner Mongolia as the research background. By studying the rheological characteristics of the grouting filling slurry in the overlying rock separation layer, the material ratio of the filling slurry was determined; A mechanical model for the evolution of mining induced overlying strata separation has been constructed, and a prediction expression for the separation opening has been derived. A method for predicting the dynamic development position of separation has been proposed. The grouting process of overlying rock separation layer was analyzed using UDEC numerical simulation to obtain reasonable grouting pressure and injection production ratio. The technology of grouting in separated-bed was implemented in 11-3101 working face of Gumen Keqing Coal Mine, and surface Deformation monitoring was carried out. The results show that: Four separation layers were generated, respectively located at 45.42m, 228.38m, 337.19m, and 363.99m above the top plate of the working face. The separation opening from bottom to top is respectively 2.62m, 1.49m, 1.39m, and 1.33m. When the grouting pressure is 6.5MPa and the injection production ratio is greater than 45%, the surface inclination deformation value was less than 3mm/m. The monitoring results show that the maximum settlement of the railway roadbed was only 58.72mm, and the grouting has a significant effect on reducing settlement.

The blind shaft sinking method as a mechanized, high degree of automation, good safety construction technology. It has the significant advantage of realizing unmanned and intelligent drilling. Taking the east wind shaft in Taigemiao mining area of Shenhua Xinjie as the engineering background, the design shaft depth is 857.5m, the design net diame-ter is 7.0m, and the design shaft wall thickness is 850mm. The feasibility of using blind shaft sinking method is ana-lyzed through geological characteristics, engineering conditions, equipment capacity and drilling classification tech-nology. The stratum and rock mechanical characteristics of the proposed eastern wind shaft are analyzed. The thickness of the bedrock will reach 870m and the proportion of the bedrock will reach 99.3%.Based on geological conditions, wellbore functions and wellbore design parameters, the drilling depth will reach 875m and the drilling diameter will be 10.2m.The problems faced by deep and large diameter wellbore drilling in whole rock formation are sorted out.The drilling grading process of deep alluvial formation in the east and thick bedrock formation in the west is compared and analyzed, and the feasibility of "one expanded well" drilling process is determined. The diameter of advance drilling is 6.5~7m, and the diameter of reaming drilling is 10.2m. It is technically feasible to sinking shaft of Taigemiao mining area with blind shaft sinking method. It provides a reference for the demonstration of the subsequent industrial test scheme and the comparison and selection of drilling process schemes in similar formations.

The mine shaft derrick is an important structure used to lift the working platform and stabilize the mine wall rock in mines. Under long-term load, derrick deformation and differential settlement may be caused, and even component fracture may be caused. In view of the structure and stress characteristics of the single diagonal shaft derrick in coal mine, ANSYS finite element software is used to build a single diagonal shaft derrick structure model and carry out stress analysis. The variation law of internal force and deformation of derricks on uneven settlement of inclined brace foundation was studied, and the influence mechanism of derrick internal force by uneven settlement was analyzed. The results show that: (1)the uneven settlement results in the redistribution of internal forces of the derrick, and the stress and displacement increase with the increase of the settlement value. (2)Compared with the lifting condition, the load on the derrick under the rope breaking condition was larger. When the uneven settlement of the foundation on the east and west sides of inclined brace reaches 31.4mm and 46.4mm, the maximum stress of the derrick reaches the safety limit, and the maximum allowable settlement value was determined. In view of the current situation of derrick settlement, the reinforcement scheme of key parts is proposed. After reinforcement, the internal force and deformation of the derrick are greatly reduced, which provides a basis for the long-term operation and reinforcement of the coal mine derrick.

In view of the risk of Rock burst caused by the mining disturbance at the end of the mining period in the 3303 working face of Xinjulong Coal Mine on the main roadway of the coal seam, the microseismic monitoring analyzed the distribution and evolution law of the fracture of the leading coal and rock mass in the working face during the mining period, and theoretically analyzed the stress distribution pattern in the protective coal pillar area of the main roadway, The stress distribution characteristics of the coal pillar area of the main roadway before and after the mining of the working face and the stress distribution and evolution law of the main roadway of the coal seam under the influence of the mining of the working face are analyzed by numerical simulation, and the occurrence mechanism of Rock burst in the main roadway area is expounded. Research has shown that the stress distribution in the protective coal pillar area of the main roadway is in a "saddle shaped" shape, and the superposition of stress and advanced support pressure gradually increases due to the influence of mining on the working face. At the end of the mining face, the increase in the connectivity range of the goaf also leads to an increase in the peak bearing pressure. The influence range of advanced support pressure in 3303 working face is about 180m. When the working face is less than 180m away from the main roadway, the impact of vertical stress caused by mining is more obvious, and the risk of impact on the roadway edge is increased. In addition, by optimizing the terminal line position of 3303 working face and adopting a targeted prevention and control technical scheme, the main roadway area at the end of the mining face has less mine shock and low energy, and the Rock burst prevention and control effect is significant.

The support of the surrounding rock of the main equipment remove gateway is an important problem that must be solved in the large mining face with the multi channel moving technology of the auxiliary alley. It's quality directly affects the removal efficiency of the working face and the safe production of the coal mine. In order to further optimize the retracting channel support scheme and improve the quality of support. Take Shendong Daliuta coal mine 52501 main equipment remove gateway as an example. Using the FLAC3D numerical simulation method. Research on the existing retracting channel support scheme. The research results are expected to be applied to the next main equipment remove gateway in the next working face. The results of the study show that, after the optimization, the deformation of the positive buttock and negative buttock of the tunnel is 302mm and 73mm. An increase of 5.9% and 7.3% compared with the existing schemes. The deformation of the roof is 236mm. More than 4.8% of the existing schemes have been increased. The support parameters of the optimized scheme can keep the main retracting channel stable.

The multi hole synchronous segmented hydraulic fracturing technology of coal seam is an efficient way to increase the permeability of coal seam. By introducing the basic principle of multi hole synchronous segmented hydraulic fracturing technology, the compressive strength of high-pressure sealing capsule and the automatic control process of multi hole synchronous segmented hydraulic fracturing system were tested in the laboratory, the industrial test was carried out in Sanyuan coal mine, the results show that the minimum damage strength of the high-pressure sealing capsule is 35MPa. The multi-hole synchronous segmented hydraulic fracturing can monitor the pressure data of each borehole in real time through the automatic control system to realize the automatic control of the fracturing process. The industrial test shows that the starting pressure of 3# coal seam is 23.3 ~ 25.4mpa. When the fracturing distance is 10m, the crack propagation time of fracturing hole is 26 ~ 38min and the crack communication time is 28 ~ 40min. The fracturing time is much lower than that of full hole section, which can effectively improve the fracturing efficiency. Compared with the unfractured coal seam, the average gas concentration after fracturing is 1.12 times that of the unfractured coal seam, the average mixing flow is 2.17 times that of the unfractured coal seam, and the average gas purity is 2.44 times that of the unfractured coal seam, which can effectively increase the permeability of the coal seam and improve the gas drainage effect.

In order to improve the accuracy of roof water damage management in safe mining of coal mine working faces, a roof water drainage design based on the “three maps method” was carried out. Taking the coal seam roof drainage project of the Nalinhe No.2 mine located in the border area of Inner Mongolia and Shaanxi as the research object, multiple geological factors were comprehensively considered, including aquifer thickness, rock brittleness to plasticity ratio, rock core recovery rate, and permeability coefficient, starting from the water source, water channel, and water filling strength. Based on the information fusion technology of ArcGIS and the “water abundance index method”, the water abundance, cracking safety, and water inrush risk of the coal seam roof aquifer were evaluated. The zoning of water abundance and geophysical anomaly areas were compared, and a drainage plan was developed. The number of drainage boreholes was dynamically optimized during the construction process. After the implementation of the plan, the amount of water and water pressure in the drainage and drilling holes significantly decreased, and the effect of “drainage and pressure reduction” was significant. The drainage technology of this working face is a powerful method to solve the problem of coal mine roof water damage, which can provide reference for the prevention and control of roof water damage in similar working faces.

With the rapid development of coal mine automation, the main coal flow transportation system of coal mine has also realized the centralized control of comprehensive automation, but the number of relevant personnel has not been reduced on the job. The main constraint factor is the blocking of the transfer point of the main coal flow belt conveyor. This paper mainly based on the situation of transfer blocking of the main coal flow belt conveyor transportation system in the suburban coal mine, and according to the on-site treatment method, designs and transforms a kind of anti-blocking device for the transfer point of the belt conveyor, gradually realizes the remote control to deal with the problem of transfer point blocking of the belt conveyor, fully liberates the on-site staff, and realizes the reduction of personnel and efficiency.

In this paper, combined with the actual situation that the surrounding rock of the shaft in Caojiatan Coal Mine is weakened by water pressure when crossing the stratum, the deformation, failure and control of the surrounding rock of the main inclined shaft of the coal mine under the action of water pressure and stress are studied by means of consulting data, field investigation, theoretical analysis, formulate calculation and numerical simulation. Based on the equivalent radius method of semi-circular arch shaft section, combined with the factors such as formation water pressure, lateral pressure coefficient, buried depth, cohesion, internal friction angle and roadway size, the mathematical expression of plastic zone distribution of shaft surrounding rock is optimized and established, and the numerical simulation verification of the model and the sensitivity analysis of the formula are carried out. Aiming at the main control factors such as stratum lithology difference and water pressure weakening, the water damage control and surrounding rock control of shaft are carried out from the aspects of inhibiting the occurrence of shear failure of surrounding rock, improving the cohesion and internal friction angle of surrounding rock, opening water discharge and pressure reduction, grouting to replace water source and strengthening the original support. It has certain reference significance for mastering the deformation and failure law of surrounding rock under water pressure-stress, carrying out relevant numerical simulation research, and carrying out wellbore reinforcement and water disaster prevention and control work.

Aiming at the problem that it is difficult to quantify the effect of fractured rock strata due to insufficient research on the evolution law of fracturing anti-scour fracture under the condition of hard roof engineering scale, the 3106 working face of Menkeqing Coal Mine is selected as the engineering background, and the research on long-hole hydraulic fracturing of narrow coal pillar high thick hard sandstone roof is taken as the starting point. Borehole leakage rate and transient electromagnetic technology were selected to study the temporal and spatial evolution law of rock fracture development, borehole leakage rate and transient electromagnetic resistivity at different strata before and after hard roof fracturing, and quantify the development law and expansion range of overburden rock fracture before and after the hard roof weakening of narrow coal pillar, providing theoretical guidance for the study of hydraulic fracture evolution law and influence range. The results show that: When the borehole is in the region affected by mining movement, the borehole leakage before and after fracturing does not change significantly. When the borehole is in the region where the original rock fracture is not developed, the borehole leakage before and after fracturing presents a multiple increase. The change of borehole leakage before and after fracturing obviously indicates the fracture expansion in the upper and lower ranges of the fractured formation. The range of fracture propagation in fractured formations is quantified from the engineering scale, and the resistance reduction phenomenon occurs when the water content in fractures increases due to the interpenetration of the fracture network in this formation is verified by the transient electromagnetic technology, which indicates that the development effect of hydraulic fracture is good, and the reliability of the weakening effect of hard roof is verified, providing theoretical guidance for the study of the evolution law and influence range of hydraulic fracture.

Aiming at the problems of heavy labor intensity, slow filling progress and high transportation cost of deep hole filling with traditional clay gun-clay during blasting operation, a new type of packing material with convenient transportation, the basic performance and sealing efficiency of the new packing material are studied by comparing the sealing performance of clay shot clay. The results revealed that the initial setting time and final setting time of the new packing material increase exponentially with the increase of water-cement ratio, and the reaction temperature of the material decreases with the increase of water cement ratio, the maximum reaction exothermic temperature is 65.6℃,which will not cause the change of emulsion explosive properties, within the safe range. The uniaxial compressive strength of new packing material decreases with the increase of water-cement ratio and increases with the increase of age, and its strength is much higher than that of clay mortar material. Under static load compression, the filling capacity of both the new type of hole filling material and clay mortar material increased exponentially with the increase of the filling length, but the filling effect of the new type of material was much higher than that of clay mortar material. Meanwhile, for the perforation packing process, when the packing length is fixed, the sealing ability of the material gradually increases with the age. However, the rate of the packing ability of the new packing material with the increase of the packing length is much higher than that with the age. The research results can not only provide theoretical reference for improving the sealing process of large and deep holes, but also have certain reference value in the development of new packing materials.

The heterogeneity of pore distribution is of great significance to reveal the occurrence state and transmission characteristics of tight sandstone gas reservoir. Based on the NMR saturation and centrifugal T2 spectrum distribution curves of middle and high rank coal samples in Qinshui Basin, the middle and high rank coal samples are divided into three types. Based on this data, the applicability of single fractal and multifractal models to the quantitative characterization of pore size distribution of middle and high-order coal samples is analyzed, and the pore fractal characteristics are revealed by integrating pore structure and reservoir physical parameters. The results show that the T2 value of class A samples is between 1 ~ 1000ms, and the saturated T2 spectrum distribution shows a "single peak", which is dominated by the development of macropores, with good physical conditions. The porosity is mostly 4.04 ~ 6.16%, and the permeability of each sample is greater than 0.1md. The T2 value of class B samples is mainly 0.1 ~ 300ms, the T2 spectrum is symmetrical "three peaks", the irreducible water saturation is relatively high, the pore development is relatively small under the influence of compaction, and the average porosity and permeability are less than that of class A. The T2 values of C and D samples are between 0.01 ~ 200 and 0.01 ~ 10ms respectively. The saturated T2 spectrum distribution shows "single peak state", and the pore permeability structure is the worst. The single fractal dimension has a good linear relationship with porosity, T2 cut off and other physical parameters. It is mainly suitable for type B, C and D samples with relatively developed micropores. At the same time, there is a good negative correlation between multifractal parameters and single fractal parameters. Affected by the difference of calculation principles, small and large pores are the key pore sizes affecting the change of single fractal parameters, while mesoporous pore distribution is the key pore size affecting the change of multifractal parameters.

The existing intrinsically safe electromagnet has the problem of low response frequency and can not meet the requirements of rapid action of hydraulic support. In this paper, a high-frequency response intrinsically safe voice coil motor is proposed as a solution for electromechanical conversion device of mine electromagnetic valve. The Ansoft Maxwell simulation model of voice coil motor is established, and the magnetic field distribution, output force characteristics and dynamic characteristics of voice coil motor are studied. The distribution of magnetic field at the air gap is uniform, and the electromagnetic force increases with the increase of magnetic potential, which is less affected by coil displacement. The current of voice coil motor meets the requirements of intrinsic safety under no-load and load. The no-load response frequency is about 6.7Hz, which is significantly higher than the existing intrinsically safe electromagnet. The load can significantly promote the release process of voice coil motor and the response speed of the motor is faster when there is a load. The research results show that the intrinsically safe electro-mechanical converter by voice coil motor is feasible, which can provide technical reference for further developing and perfecting the mine intrinsically safe electro-mechanical converter with high response.

In view of the existing problems such as long processing process, large area and poor operation effect,the project proposes the underground direct filtration treatment technology and equipment based on organometer-rolled ultrafiltration membrane, and conducted pilot study in a coal mine in NingDong area. The results show that under the condition of low flux, the direct filtration system runs stably, there is no obvious membrane contamination, and the membrane flux decays less than 3%. When the initial flux was 47.4 L/(m2·h) and the recovery rate was 84.6%, the flux decreased by 9.01% after 48 days of operation. The attenuation of membrane flux was mainly caused by membrane pollution caused by cake deposition. At the same time, under the constant pressure operation mode, the recovery rate of the direct filtration system is improved, and the water intake decreases with the increase of water production. In the influent turbidity range of 10~30 NTU, the water quality of direct filtration system is relatively stable, and the turbidity of water production is lower than 0.5 NTU. The overall operation results show that the direct filtration technology has the advantages of short treatment process, stable water quality and strong anti-pollution performance, and has obvious application advantages in underground.

Coal mine belt conveyor is the main transportation tool of raw coal, and its normal operation is very important to the safe production of coal mine. In the process of belt transportation, the foreign matter such as large coal gangue bolt is the main cause of belt clamping and deviation tearing, which restricts the safe and efficient operation of belt conveyor.The key factors leading to the low accuracy of intelligent picking and detection of belt foreign objects are complex detection conditions such as the complex environment with high dust concentration and poor lighting in the mine, the fast speed of coal transport belts and the easy obstruction of foreign objects from each other The complex detection environment such as large coal dust underground, poor lighting, and fast coal transport belt speed are the key factors that lead to low detection accuracy of intelligent picking of foreign objects on the belt. Based on the actual monitoring data of an underground belt conveyor in a coal mine in Datong, Shanxi, this paper improves the YOLOv7 detection algorithm; firstly, through the adaptive contrast enhancement algorithm, the contrast of the belt monitoring image is enhanced, which is beneficial to improve the outline definition of the target image; secondly, in the trunk In the extraction network, a multi-scale mixed residual attention mechanism is proposed to enhance the ability of YOLOv7 to extract foreign object features and interfere with the background. At the same time, it introduces full-dimensional dynamic convolution to replace the ordinary convolution in the ELAN module, reducing the redundant data in the convolution. accumulation. Finally, a weighted bidirectional feature pyramid network and 4 detection heads are used to output model prediction results to improve the network's detection efficiency for foreign objects of different sizes. Compared with CPU GPU, TensorRt engine was used to convert the weight of the trained and improved YOLOv7 model and deploy it to the detection platform. Online detection was performed on the belt conveyor surveillance video with a resolution of 1920 1080 in coal mine to realize real-time monitoring of foreign bodies.Through experiments, the improved YOLOv7 model is superior to YOLOv5 and YOLOv7 in the recognition accuracy and speed of foreign objects in the downhole belt, and the recognition accuracy and speed of foreign objects in the downhole belt are 94.3% and 24fps, respectively. Compared with the YOLOv5 model and YOLOv7 model, the average recognition accuracy rate has increased by 4.6% and 3.8% respectively; the average recall rate has increased by 4.5% and 3.8% respectively; the detection time has been improved by 0.007s and 0.003s respectively.

With the development of China's coal mining industry technology, many problems of coal machine equipment manufacturing industry have been exposed. Aiming at the problems of information island, information asymmetry and low business flow efficiency of all participants in the supply chain of coal machinery equipment manufacturing under the traditional mode, a multi-chain structure of coal machinery equipment supply chain information management platform based on blockchain technology was proposed. Connect suppliers in the supply chain, manufacturing and remanufacturers, coal mining companies, and regulators and financial institutions. The platform technology architecture suitable for the supply chain of coal machine equipment is designed, the master-slave multi-chain network structure is built to simulate the supply chain of coal machine equipment and the throughput and storage performance are tested, and the practical advantages of blockchain technology in the field of coal machine equipment manufacturing are discussed, which provides a new direction for the integration of coal machine manufacturing and a new generation of information technology.

In the process of coal gangue sorting, traditional methods use visual identification and belt speed to predict the real-time position of coal gangue. However, due to slippage and deviation of the coal gangue during high-speed, long-distance transportation on the belt, the actual position often differs from the predicted position, leading to issues like missed or incorrect grabs by robotic arms, thus affecting sorting efficiency. To address this problem, this study proposes an improved ORB matching algorithm for the secondary positioning of coal gangue. Firstly, it introduces local adaptive gamma correction to oFAST feature detection, enhancing matching accuracy under low lighting conditions. Additionally, to counter the dynamic interference caused by high-speed movement of the gangue, this paper combines BEBLID descriptors and the GMS algorithm for rapid feature matching, and employs the RANSAC algorithm to optimize feature point selection, thereby enhancing the robustness of the algorithm. Ultimately, the minimum bounding rectangle is calculated through matching points to obtain the position. Experimental results show that the proposed algorithm improves the matching accuracy of coal gangue under scale, illumination, and angle changes by 16.7%, 36%, and 22% respectively, compared to the traditional ORB algorithm, with an average error of 1.29mm and an average matching time within 40ms. This effectively enables gangue matching and positioning in complex scenarios.

In view of the characteristics of large consumption of flotation chemicals during the recycling and utilization of coal gasification fine slag, the coal gasification fine slag in a certain place in Yulin, Shaanxi Province was used as the research object, through whole grain flotation, and the particle size analysis of whole grain flotation products and the calculation of perfect indicators and combustible gas recovery rate of each particle level flotation product, combined with the SEM, XRD and FTIR results of 0.5-0.25 mm and 0.25-0.125 mm were analyzed, and it was judged that +0.125 mm coal gasification fine slag could not effectively separate organic and inorganic matter by flotation, so a pre-grading-flotation combined process was proposed, and the flotation distribution release experiment was carried out on -0.125 mm, and the enriched refined coal after -0.125 mm flotation was combined with the pre-graded +0.125 mm part as the final refined coal, and a concentrate with an ash fraction of 26.38% and a yield of 66.42% was obtained. Compared with the whole grain flotation process, pre-grading-flotation combination not only has the advantages of simple process flow, low chemical consumption, flexible process control, etc., but also has the advantages of high yield and low ash content, and can recover gasified fine residue more efficiently.

Digital transformation is a systematic project. The digital drive represented by mobile Internet, Internet of things, cloud computing and big data is becoming an important means and effective path to break the bottleneck of coal industry development and accelerate the transformation and upgrading of coal industry. Starting from the current situation of digital development of coal industry and the digital transformation of coal enterprises, this paper puts forward three key tasks : comprehensively improving digital ability, deeply excavating data value and vigorously promoting economic transformation. At the group level, it is proposed to consolidate the digital basic capabilities, improve the five major capabilities of safety production scheduling, business and financial integration, process-based collaborative office, and operation and maintenance support digital governance capabilities. At the coal mine level, five construction contents are put forward, including data transmission capacity improvement, digital network construction, intelligent perception platform construction, comprehensive management and control information system construction, and coal mine intelligent capacity improvement construction. This paper aims to provide reference for the implementation path of digital transformation of coal enterprises.

Aiming at the problem explosion-proof diesel engine support carrier is difficult to transport the thin coal seam hydraulic support, by analyzing the role of the support carrier in the multi-channel retracement process of the thin coal seam mining face, the function parameters of the new thin coal seam battery support carrier are determined . The bearing function structure matching the thin coal seam support is designed. The characteristics of the vehicle axle load distribution and the adaptability of the driving mode are analyzed. The switched reluctance motor drive system and the electric feedback braking system are designed. The charging and discharging characteristics of the large-capacity special lead-acid battery are analyzed. The use and maintenance of the battery and the method of improving the endurance mileage are pointed out. The vehicle related intelligent configuration and the advanced technology are introduced. The industrial test shows that the performance of the new thin coal seam battery support carrier fully meets the use requirements.

Scraper conveyor is the core equipment of fully mechanized mining face in coal mine. Due to the bad working environment and complex working conditions, faults such as chain stuck and chain broken often occur. The cylindrical friction torque limiter has the advantages of good overload protection performance and high reliability. Therefore, in order to study the overload protection performance of the cylindrical friction torque limiter, the whole scraper conveyor model was established by AMESim, and the torque limiter skid control model was built by Matlab/Simulink for co-simulation. The overload protection characteristics of the cylindrical friction torque limiter under impact and stuck chain conditions were studied. The overload protection effect of scraper conveyor by different installation position of torque limiter was analyzed. The results show that under the impact and chain clamping conditions, due to the friction slip of the torque limiter, the force of the scraper conveyor protected by the torque limiter is relatively stable without sudden increase, and the isolation peak load of the torque limiter is significant. When the torque limiter was arranged in the middle of the reducer, the protection effect for the scraper conveyor and its driving system is the best, the research of cylindrical friction torque limiter provides theoretical guidance and technical support for improving the reliability and life of scraper conveyor.