The design value of the horizontal load after the superposition of the horizontal thrust of the upper grid frame of the large-span coal storage yard and the coal pile pressure of the coal storage yard is relatively large, and the requirements for the bearing capacity of the foundation are relatively high, especially the anti-slip and anti-overturning capabilities. When the foundation is deep fill, collapsible soil, or weak soil layer, foundation treatment is generally needed to provide sufficient foundation bearing capacity. Based on engineering examples, this paper compares the economic indicators of various foundation treatment schemes, and through the MIDAS GTS finite element analysis verification, proposes the applicability of the inclined pile group scheme, which provides a certain reference for similar projects.The design value of the horizontal load after the superposition of the horizontal thrust of the upper grid frame of the large-span coal storage yard and the coal pile pressure of the coal storage yard is relatively large, and the requirements for the bearing capacity of the foundation are relatively high, especially the anti-slip and anti-overturning capabilities. When the foundation is deep fill, collapsible soil, or weak soil layer, foundation treatment is generally needed to provide sufficient foundation bearing capacity. Based on engineering examples, this paper compares the economic indicators of various foundation treatment schemes, and through the MIDAS GTS finite element analysis verification, proposes the applicability of the inclined pile group scheme, which provides a certain reference for similar projects.

In order to solve the problems of low roadway tunneling efficiency and slow mining area preparation, the reasons affecting the excavation efficiency were analyzed from the aspects of support design, blasting parameters,corollary equipment,efficiency of gangue transportation, construction quality and organization management.”Five-in-one” rapid construction technology of rock roadway blasting under complex and multi-factor conditions was put forward,which inclued differential support design,mechanized equipment and improvement,Linear Energy Accumulation Smooth Blasting,flexible continuous gangue discharging system,Construction technology and labor organization guarantee.Engineering practice has been carried out in the track roadway of xi’san lower panel, Rapid construction line of rock tunnel blasting was comprised by “hydraulic drilling-Linear Energy Accumulation Smooth Blasting- Safty and efficient support scheme-flexible continuous gangue discharge". Practice shows that Rapid tunneling under complex and multi-factor conditions was realized by adopting "five-in-one" rapid construction technology of rock roadway blasting,The efficient driving system of fast drilling, efficient tunneling,continuous drainage of gangue and effective support is realized.The tunneling footage was increased by 126%,which is 86 meter per month,the artificial efficiency was increased to 2.04 meters per month and each employee,Footage efficiency of rock roadway blasting was significantly improved.

The 31113 return airway of Lijiahao Coal Mine was located in the coal pillars at the boundary of the dislocation working face, and the roadway deformed greatly at the 31113 working face before the stoping. In order to obtain the mechanism of large deformation of the roadway and propose the control technology, the method of numerical calculation and field measurement was used to study the force characteristics and failure laws of the surrounding rock of the roadway. The research results showed that the superposition of the concentrated stress of the coal pillars in the upper group of coal seams and the lateral support pressure of the 31112 face in the lower group of coal seams resulted in a substantial increase in the roadway force, and the lack of original support strength resulted in a large deformation of the roadway. The main reason for the substantial increase in superimposed stress was that the concentrated stress transmitted by the coal seams on the dislocation working face comes from the boundary coal pillars, and the downward conduction stress of the boundary coal pillars had a larger influence than the inter-section coal pillars, and the attenuation was slower. At the same time, the superposition of lateral support pressure intensified the imbalance of the surrounding rock force of the roadway. The damage range of the roadway surrounding rock on the side of the auxiliary side and the roof of the auxiliary side near the adjacent mined-out area was relatively large, causing local instability of the roadway and forming Large deformation. The original support plan was revised based on the actual damage range, and the reinforcement support plan was designed. The field measurement showed that the roadway deformation was significantly reduced after the reinforcement support.

In response to the problem of serious deformation and damage of the surrounding rock during the service period of the reused roadway, the influence of lateral mining stress on the reused roadway is analyzed, and the deformation law and damage mechanism of the surrounding rock transportation of the reused roadway are revealed. The support strategy of using strong and flexible pier pillar to supplement the support of the roadway is proposed, and the support strength of the joint support body of "coal pillar - in-roadway support" is analyzed by establishing the mechanical model of broken reused roadway slab and pier pillar support, and theoretically calculating the support force load requirements to be satisfied by the pier pillar. The design and application of flexible piers were carried out in terms of support environment, material selection of filling body, structural design of support body and construction process, taking 3306 haulage road of Wangpo coal mine as the actual background. The field monitoring results show that: the deformation of the roadway surrounding rock within the overrun working face of the reused roadway is small, and the influence range is 200m of the overrun working face; the deformation within 50m of the lagging working face is the area of rapid growth of deformation, which should be focused on maintenance. By using flexible strong pier column in-road support can effectively alleviate the problem of serious deformation of the surrounding rock of the reused roadway and keep the deformation of the roof plate at a low level.

This paper takes the Ⅱ 1044 fully mechanized working face of Taoyuan Coal Mine as the research background, uses FLAC3D to simulate the working face advancing towards the fault, studies the vertical stress distribution law, the evolution law of the plastic zone, and the slip amount of the fault face when the working face advances to different positions, and formulates scientific and effective fault crossing technical measures and safety measures accordingly. The research shows that when the working face is 40 m away from the fault, the stress at the fault is about 20 MPa, and the plastic zone at the fault has reached the direct bottom. At the same time, a large range of plastic zones appear at the floor and roof of the working face, and the damage is serious. The damage depth of the floor can reach 47.2 m. As the working face moves towards the fault, the fault will be completely destroyed. Therefore, when the working face is 40 m away from the fault, Malisan is injected into the broken roof area of the working face for reinforcement, and cement slurry is injected into the 25-55 supports of the working face for reinforcement. After grouting, the support pressure of the working face is basically stable.

The accuracy requirements of efficient，safe and intelligent coal mining production for the top and bottom interfaces of coal seam and subsurface three-dimensional (3D) geological structures are becoming more and more high. The imaging resolution and accuracy of traditional geophysics detection methods are not able to satisfy the practical requirements. Full-waveform inversion (FWI) technology is able to construct very accurate 3D subsurface geological structures and represents the core technique for overcoming the difficulties in coal mining production. This research applies 3D elastic wave FWI to construct subsurface 3D geological structures for Shanxi Xiaobaodang NO.1 coal mine 112204 coal face. Spectral-element method and GPU technique are used to simulate the wave propagation efficiently and accurately. Multi-scale, multi objective functions and multi-wave inversion methods and technologies are developed. The well-log data is used as prior information for regularization constraints, which helps reduce inversion non-linearity and uncertainty. Finally, 3D subsurface elastic velocity structures of 112204 coal face are obtained. The top and bottom interfaces of coal seam are imaged with high-resolution (0.5 m). 3D spatial distribution of the coal seam is finely characterized and delineated. The inversion results match well with the well-logging data. Based on these results, the objective of transparent coal face is achieved.

Taking No. 4 coal seam in the Binchang mining area as the research object, aiming at the problems existing in the construction process of long borehole segmented hydraulic fracturing in the medium-hard coal seam, such as long construction period, high accident rate, high risk, and poor economy, this paper uses the methods of experimental analysis, numerical simulation and system process optimization to study the new restrictor suitable for segmented fracturing in No. 4 coal seam, as well as the reasonable pump pressure. The improved fracturing technology was used to complete the hydraulic fracturing construction of 3 boreholes over 500m with a total of 22 sections. The range of pumping pressure is 7.56~9.70MPa with discharge volumes of 18.63~22.11m3/h, and all without accidents in the borehole. After the improvement, the duration of single hole hydraulic fracturing is reduced from 12 days to 7 ~ 8 days, the initial gas drainage volume of fracturing borehole is 1.29 and 1.38 times that of conventional mode, and the attenuation coefficient of gas drainage volume is reduced to 9.1% and 6.8% of conventional mode. The gas drainage effect of fracturing borehole has been greatly improved. The research results provide a new technical way for high-efficiency gas drainage in long directional drilling areas of the medium-hard coal seams.

Aiming at the technical difficulties of gas extraction in the thick seam with high gas content of Sima Coal Industry Co., Ltd., this paper discusses the gas extraction effect under different drilling arrangement modes, analyzes the influence of drilling parameters on crack expansion, and puts forward key technical parameters such as reasonable drilling arrangement mode, drilling spacing, drilling radius and effective time of gas extraction suitable for the thick seam of Sima Coal Industry Co., Ltd. On this basis, combined with the geological conditions of gas occurrence in No. 3 Coal Seam, the layout pattern of gas extraction boreholes in thick coal seams was designed. The mining roadway in 1207 working face is divided into three gas extraction sections, and the drilling layout mode combining "five hole layout" and "three hole layout" is implemented. The number of boreholes is reduced by about 30%, the extraction time of the first section of the working face is shortened to 110 days, and the gas extraction efficiency is increased by 70%, which greatly alleviates the time tension in the process of mining and mining face extraction connection.

Accurate detection of the location of microseismic activity in the roof rock, especially the vertical location of the seismic source, is an important basis for understanding the spatial structural characteristics of the overburden rock, and is of great significance for achieving accurate prevention and control of impact ground pressure. Due to the limitation of software algorithm and the way of station arrangement at near horizontal coal seam, the vertical positioning accuracy of microseismic events measured by traditional underground microseismic monitoring system is low, which cannot meet the demand of accurate monitoring of overburden structural transport. In view of this, on the basis of the underground microseismic monitoring system, ground monitoring stations were added to form a combined up-and-downhole microseismic monitoring system, and an engineering demonstration was carried out in the 3111 area of Shilawusu coal mine. The data analysis shows that the combined microseismic monitoring system is more effective in monitoring microseismic events with energy greater than 1.0E+03J, and the monitored microseismic event elevation is on average 35.2m higher than that of the conventional underground microseismic monitoring system, and the seismic source positioning results generally fit better, indicating that adding surface monitoring stations can effectively improve the vertical positioning accuracy of seismic sources. The research results provide experience and guidance for the accurate detection of spatial structure of near-horizontal coal seam overburden.

In order to study the relationship between roadway floor heave, wall heave deformation, roof fracture and energy accumulation and dispersion in Tunbao Coal Mine's fully mechanized top coal caving face,Took the WII02040501 fully mechanized caving face of Tunbao Coal Mine as the engineering background, Through theoretical analysis, on-site monitoring and engineering verification, analysis the key roof strata of WII02040501 fully mechanized top coal caving face. Calculated the characteristic laws of energy released from key layers in different layers transferred to the working face, studied the distribution law of microseisms during mining in WII02040501 fully mechanized top coal caving face,developed the practice and effect inspection of roof cutting project. Research shows:existed 6 sub key layers and 1 main key layer on the roof of WII02040501 fully mechanized top coal caving face, Microseismic events are mainly distributed within 100m above the coal seam, and 104J energy level and above are distributed within 50m above the coal seam. Calculated that the elastic energy transferred from the breaking of two sub key layers to the working face is7.80×107Jand3.13×105J, Comprehensively identify the two sub key layers close to the working face as the induced key layers.designed and engineering practice the top cutting blasting scheme of WII02040501 fully mechanized top coal caving face, borehole peeping and periodic weighting step distance analysis show that roof fractures are obviously developed and weighting step distance is effectively reduced,the roadway deformation is effectively controlled,The safe production of the working face is realized.

In order to extend the service life of the cantilever roadheader pick system, and reduce the system operation and maintenance costs, according to the maintenance need of the pick system and the resulting spare parts need, a joint policy of preventive maintenance and spare parts inventory based on periodic inspection is proposed .A (m,τ,S,s) joint decision-making model for the maintenance and spare parts inventory of the pick system is established with the goal of minimizing the cost rate and considering availability constraint. Based on engineering data, the optimal objective and corresponding decision variables are obtained by genetic algorithm. The results show that when the preventive replacement threshold is 8 pieces, the inspection cycle is 12 days, the target inventory level is 75 pieces, and the spare parts ordering threshold is 45 pieces, the availability of the pick system is 0.87, and the cost rate reaches the minimum of 162.45 yuan/h. Therefore, searching for the global optimal maintenance plan and the matching spare parts ordering and inventory plan to achieve more reasonable integration and optimization of maintenance and spare parts inventory can further improve the safety and economy of the pick system operation.

The triple soft coal seam bottom lane with double lane arrangement faces multiple mining influences and is often subject to greater damage and deformation, accompanied by serious floor heave disasters. In order to investigate the mechanism of the occurrence of floor heave in the lower section of the working face with double lane arrangement and propose the corresponding control technology, this paper takes 3309 transport lane of Hancheng Sangshuping No.2 shaft as the engineering background, establishes the mechanical model of the neighboring lane bottom slab in the mining area through Rankine soil theory, and adopts FLAC3D finite difference program to simulate the distribution law of mining stress and the range of plastic zone when the working face with double lane arrangement is retrieved, the research results show that: (1) The adjacent workings began to dropsy at 210m in front of the workings and the rate of increase of the dropsy displacement increased at 40m in front of the workings, with the maximum dropsy amount reaching 662mm. (2) According to the stress equation of the rock of the roadway floor calculated by the mechanical model, we can get that the damage of 3309 roadway floor is linearly related to the stress concentration coefficient of the two gangs of the roadway, and the slope of the coal pillar gang stress concentration coefficient K' axis Δ1 is 6.520. (3) According to the numerical simulation results, the depth of the plastic zone of the bottom slab of 3309 working face is maintained at about 3m, and the maximum vertical stress of the coal pillar behind the working face reaches 44.5MPa due to the influence of mining, which leads to the penetration of the plastic zone of the neighboring roadway gang. Based on the mechanism of the occurrence of the floor heave in the neighboring roadway in the mining area, the pre-cracking top cutting and pressure relief technology was proposed to control the deformation of the roadway in the No. 2 shaft 3309 transport roadway, and good results were achieved to ensure the normal production of the mine and the safety of personnel and equipment. Keywords：mechanisms of floor heave occurrence; floor heave control; blast pre-cracking topping and pressure relief; numerical simulation; adjacent roadway

In order to improve the reliability and accuracy of acoustic emission prediction technology in coal roadway driving, and to reduce the influence of working noise on monitoring signal and monitoring effect in coal roadway driving, roadway support and borehole construction, this paper adopted the method which combined stress loading experiment in laboratory and the field monitoring and analysis, and studied the noise processing method of acoustic emission monitoring signal in the heading face of coal roadway. The results shown that the frequency distribution of operational signals from comprehensive excavator driving, drilling anchor and drilling rig drilling ranged from 0 to 8000 Hz, and the main frequency was in the range of 500 Hz, 3000 ~ 5000 Hz, 7500 ~ 8000 Hz, had“W” shape distribution features. The width of main frequency band of AE signal was 0 ~ 500Hz during the failure process of coal and rock samples, the dominant frequency did not exceed 250 Hz. In combination with the characteristic difference between the acoustic emission signal in the rupture process of the laboratory coal and rock specimen and the acoustic emission mixed signal in the coal roadway excavation and the spectrum characteristics, we adopted the reasonable configuration of zero drift value and signal threshold value, and combined the band-pass filtering and RII filtering to establish the noise filtering method of the monitoring signal, which realized the extraction of the effective acoustic emission monitoring signal during the coal roadway excavation operation. The noise filtering effect was conformed to the reality. This paper provided a method support for real-time acquisition and noise filtering of acoustic emission monitoring signals, and brought high accuracy monitoring and early warning. It had certain guidance and reference significance.

Abstract: The safety of excavation works should be ensured in the rapid excavation of multiple mining roadway. At present, the roadway in the third mining area of Tenghui Coal industry is excavated under the goaf in the remining area. In order to increase the tunnelling efficiency of the roadway in the third mining area and guarantee the safety of the roadway during tunnelling, analytic hierarchy process (AHP) is adopted to analyze the weight of the major influencing factors of roadway safety, and the safety of the roadway in the remining area under the current tunnelling conditions is evaluated by combining the multi-index comprehensive analysis method. The weights of different factors under current mining conditions are obtained, and the values of different factors are given. Based on the impact factor value and comprehensive analysis method, the safety factor was defined, and the maximum value of the safety factor was determined to be 0.0691 and the minimum value of 0.075. The maximum and minimum value of the safety factor were averaged to divide the roadway safety into five levels. By further introducing the above index value in the driving roadway of the 3 mining area of Tenghui Coal Industry, the safety factor value of the current production conditions is calculated to be 0.2619, and the safety level belongs to the relatively safe range.

The coal mining area in the middle reaches of the Yellow River Basin of Shaanxi Province in China is characterized by shallow burial depth, simple geological structure, thick coal seams and serious coal mining collapse. In order to study the influence of the surface movement and deformation of the ultra-long working face in the aeolian sand landform in the northern Shaanxi coal mining area in the middle reaches of the Yellow River Basin, and to clarify the surface deformation parameters of the ultra-long working face in the aeolian sand area, a long-term and systematic study was carried out on the S12002 working face of the Ningtiaota Mine in northern Shaanxi. Surface deformation monitoring is carried out, and the surface deformation parameters are compared and analyzed with the surrounding mining areas with similar geological mining conditions. The research results show that the surface deformation of the ultra-long working face in the wind-deposited sand area of northern Shaanxi is characterized by fast subsidence response, rapid convergence of boundary subsidence, discontinuous oscillatory fluctuation of surface subsidence, and serious surface damage at the open cut off by surface movement deformation characteristics and related parameters, the maximum subsidence coefficient is 0.59, the maximum subsidence amount is 2442.4mm, the horizontal deformation is large, the maximum horizontal movement value is 832.3mm, the maximum subsidence speed is 354mm/d, the surface active period is 54d, and the subsidence period is active. The amount of subsidence accounts for 96% of the total subsidence, and this area has obvious characteristics of high-intensity mining damage; the comparison analysis between the northern Shaanxi mining area and the surrounding similar mining areas shows that the subsidence coefficient is smaller than that of the Shendong mining area, and the subsidence coefficient and the working face geological mining conditions parameters have a certain relationship. Correlation, when the base mining ratio is less than 20, it is easy to produce surface cracks. When the width to base ratio is larger, the subsidence coefficient is larger. When the overlying rock loosening ratio is larger, the subsidence coefficient is smaller. slowing effect. It enriches the research data on the surface deformation characteristics of the ultra-long working face in the western aeolian sand area, and provides a basis for the mining conditions and ground protection of similar coal mines.

In order to ensure the safety, stability and efficiency of the rapid tunneling system, the structural strength and design rationality of the anchor unit are very important; Firstly, according to the actual working conditions, the mechanical model of the drilling process of the anchor unit is established, and the relationship between the drilling resistance and the resistance moment is obtained; The reliability analysis of the structural strength of the anchor unit is carried out by ANSYS, and the rationality of the structural design is verified; By constructing the drill pipe vibration model in the drilling process, using ABAQUS to analyze the modal law of the anchor unit under the prestress, and combining with MATLAB to solve the lateral vibration displacement, velocity and acceleration in the drilling process, it is verified that the velocity and acceleration of the drill pipe can be used as the numerical characteristics to judge the coal and rock properties when drilling in different rock layers; The structure of the anchor unit is optimized by using the designexpander optimization module. The quality of the optimized anchor unit is reduced by 6.24% under the condition that the stress, deformation and resonance frequency meet the requirements, and the optimization of the anchor unit structure is realized; Through the similar test of anchor drilling, the optimized anchor parts can meet the strength requirements; When drilling in different surrounding rocks, the vibration response of the drill rod for anchor drilling is obvious. This conclusion can be used as the theoretical basis for coal rock identification, and provides the precondition for automatic anchor.

In order to explore the damage characteristics of water-saturated coal under thermal shock, a high and low tem-perature test chamber was used to treat the coal samples with different temperature differences. The microscopic observation of the changes of the fissures on the coal surface before and after the shock was carried out from the microscopic scale, and the macroscopic changes of the uniaxial compressive strength and permeability of the coal body after the thermal shock were explained through the microscopic and mesoscopic scales. The test results show that the number of cracks on the surface of the water-saturated coal sample after cold shock and heat shock increases, and the cracks are connected to each other, and the crack area in the same area increases; The more significant the effect is, the smaller the compressive strength of the coal body is, and the higher its permeability is. The frost heave force generated by the water-ice phase transition and the deformation of mineral particles are mutually restricted to generate thermal stress, which is the main factor leading to the deterioration of coal body structure.

Aiming at Yangchangwan lignite, Shengli fat coal and Yangquan anthracite, the topological structure of raw coal pore space was reconstructed based on X-ray CT scanning technology. And the THM coupling experimental platform for methane displacement by gas injection of loaded raw coal was established, and the experiment of CH4 displacement by CO2 injection in raw coal under different conditions was conducted. Results show that: the porosity development degree, spatial distribution and connectivity of YCW lignite, SL fat coal and YMY anthracite become worse in turn. The CO2-ECBM process in raw coal goes through three stages: the replacement is dominant in the early stage; the replacement, carrying and dilution coexist in the middle stage; the carrying and dilution are dominant in the later stage. Stress and gas injection pressure can significantly affect methane displacement efficiency, and the topological property of coal pore is an important influencing factor. However, the strong adsorption of YMY anthracite can improve the methane displacement defect caused by the lack of seepage channel to a certain extent.

Due to the complex underground space environment in deep mines, transmission interruption and high transmission delay often be appeared in the process of communication transmission. To solve it, a large number of nodes need to be added which increases the communication transmission cost. We proposed a probabilistic routing algorithm based on message utility in coal mine. Under the existing conditions, we use the sociality of people to assist in decision-making transmission strategies. Firstly, based on the movement characteristics of underground nodes, the movement track similarity, node encounter duration and node similarity are defined; Secondly, the underground work nodes are classified into different communities according to their sociality, and different message forwarding strategies are used inside and outside the communities to improve transmission efficiency; Finally, by adding an ACK deletion mechanism to limit network redundant copies, network congestion is effectively avoided. The simulation results on One platform show that the algorithm can improve the success rate of message delivery and reducing the network delay in the mine scenario with poor communication environment.

In order to solve the problem of unbalanced energy consumption of wireless sensor network (WSN) nodes in narrow and long space, this paper proposes an equidistant uneven layered deployment strategy of sensor nodes with balanced energy consumption in narrow and long space. According to the principle of radio communication, the WSN energy consumption model is established, and the narrow and long space is abstracted into linear chain network space to establish the network model. Based on the energy consumption model, the narrow and long space is divided into equidistant zones. Each zone adopts the layered network topology. For the top nodes of the narrow and long space, the unequal density deployment mode is adopted, and the side nodes are deployed in rectangular structure. Combined with the traditional LEACH protocol, a probability function is introduced to calculate the probability of each node becoming the cluster-head node. The improved routing protocol is used to cluster the nodes in each partition and select the cluster-head node. Based on this protocol, the proposed deployment mode is simulated and analyzed. The simulation results show that compared with other deployment modes, the narrow-long-space deployment strategy can not only reduce the energy consumption of network nodes, but also make the life cycle of nodes in each zone basically the same. Meanwhile, the number of deployed nodes can be saved by 6% ~ 7% compared with other deployment modes. The deployment cost and energy consumption of the network are reduced, and the problem of "energy hole" is solved.

The high-water holding capacity of coal gasification fine slag seriously affects its resource utilization. In this paper, the basic reason of the high-water holding capacity (64.64%) of coal gasification fine slag was clarified by studying the apparent morphology (SEM), the distribution of main elements (EDS) and pore structure (BET). Subsequently, through constant temperature drying experiments at different temperatures, the drying kinetics of coal gasification fine slag in constant temperature drying process was studied, and the logarithmic constant temperature drying kinetic model at various drying temperatures was established. Additionally, the drying temperature is from 80 to 120 ℃, and the equivalent moisture diffusion coefficient De of the sample during constant temperature drying is between 0.0025 and 0.0048. The higher the temperature, the greater the De value, the easier the moisture diffuses from the inside of the particles to the outside, and the easier the drying.

Low-rank coal has poor surface hydrophobicity, resulting in low flotation efficiency. As a pretreatment process before flotation, conditioning could improve the dispersion of non-polar oil and the hydrophobicity of particle surface, thus effectively improving the flotation effect. The influence of conditioning speed and time on the flotation of low-rank coal was studied by using low-rank coal from a coal preparation plant in Inner Mongolia. The effect of conditioning on the surface properties of coal particles was analyzed by Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, and contact angle analyzer. The results showed that the yield and ash content of clean coal increased with the increase of condition speed and time. When the amount of diesel oil was 7 kg/t, the condition speed was 2400 r/min, and the conditioning time is 1 min, the combustible recovery and flotation perfection index reached the maximum. The contact angle of the coal particle surface gradually increased with increasing conditioning speed, but when the speed was too high, the contact angle decreases slightly. Compared with the coal sample before conditioning, the carbon content on the surface of the coal sample increased after conditioning, the C-C/C-H functional group content increased, the C-O functional group content decreased, and the surface hydrophobicity of the coal sample increased. The increase of conditioning speed increased the dispersion of non-polar oil and the probability of collision between the collector and coal particles. However, the shear force may cause the desorption of the agent adsorbed on the surface of the coal particles, thereby reducing the flotation effect at overhigh conditioning speed.

In order to solve the problem of energy waste and low transportation efficiency caused by the mismatch between the running speed of shearer and scraper conveyor, and the continuous high-speed running of scraper conveyor, through the study of two-way coal cutting technology, the running phase of shearer and scraper conveyor is analyzed, and a decision model of coordinated speed adjustment between shearer and scraper conveyor is established, which aims at optimizing the consumption of scraper conveyor, the fluctuation of transportation speed and the transportation efficiency. Seagull Optimization Algorithm is used to solve the optimal synergistic speed of each stage under the constraints of speed range and coal load of shearer and scraper conveyor. Finally, the simulation experiment with data from a coal mine working surface shows that the shearer traction speed and scraper conveyor transport speed can be planned by using the decision model of coordinated speed control between shearer and scraper conveyor, which can effectively reduce 28.7% energy consumption of scraper conveyor and increase transport efficiency by 6.8% without affecting production tasks.

Innovation is an effective way for coal enterprises to achieve high-quality development and "double carbon" goals. This paper selects coal listed companies from 2014 to 2020 as samples, measures the innovation efficiency of coal listed companies by improving Richardson's investment expenditure model, and analyzes the impact of executive compensation stickiness on them and the regulatory role of board characteristics in the middle. The research finds that: executive compensation stickiness is significantly negatively correlated with the innovation efficiency of coal enterprises; The size of the board of directors and the independence of the board of directors negatively regulate the role of executive compensation stickiness on innovation efficiency. The research conclusions provide new ideas for the improvement of innovation efficiency of coal enterprises, and have certain enlightenment significance for coal enterprises to achieve high-quality development.

The composition of the cost of the mine project is discussed in detail, the main factors affecting the cost are systematically analyzed, and the estimation method of total cost and cost items according to calculation, calculation and analogy prediction methods are proposed, which provides a basic basis for the establishment and cost estimation of the cost bank. The cost database, cost estimation model and cost index analysis model have been developed, a cost estimation system integrating query, estimation and analysis has been built, the centralized storage and online query of scattered cost data have been realized, the rapid estimation of the cost cost of the proposed project has been realized, and a certain region and specific students have been realized. Online analysis of cost indicators under the condition of production scale. The cost bank, cost estimation model and cost index analysis model are independent and interrelated.It provides the basis for the preliminary cost estimation and production and operation cost prediction of the mine project, provides accurate data for the pre evaluation, in-process evaluation and post evaluation of the project, provides a scientific and effective judgment basis for the rationality of the cost level, improves the work efficiency of the mine project cost estimation, improves the professionalism and scientificity of the technical and economic work, and provides strong support for the enterprise decision-making, Provide a strong guarantee for the development of digital economy in the industry.

In order to determine the optimum location for entry of the lower No. 3 coal seam with the variable seam spacing and close coal seams of Meihuajing coal mine in Ningxia, by combining the 5 interlayer boreholes information of the lower No. 3 coal seam and the 232204 panel face in the upper No. 2 coal seam, the failure range of the floor after the upper No. 2 coal seam mining is explored through theoretical analysis, field monitoring and numerical simulation. The fracture development regularity and stress distribution characteristics of the floor with information of 5 interlayer boreholes after the upper coal seam mining are analyzed, and the optimum location for entry is determined. The main conclusions are as follows: 1) the maximum failure depth of the floor with information of 5 interlayer boreholes is 19.57 m and the lower No. 3 coal seam is basically disturbed by the mining of the upper No. 2 coal seam. 2) the inverted trapezoidal zone appears in the fracture development areas with variable spacing mining, and the maximum horizontal distance between the stress-relaxation area and boundary pillar is 9.69 m. 3) The entry of lower coal seam is arranged with an inner stagger distance of 15 m considering a 1.5 safety factor and a scheme of partition entry support under variable layer spacing conditions is proposed. The results can provide a reference for the layout of entry with similar conditions.

There are many problems in the main transportation system of coal mine,such as manual spot inspection,remote centralized control can not be implemented,monitoring data is incomplete,intelligent control method is lacked,there is no efficient means of fault detection.In view of the above problems,this paper puts forward the method of segment extraction key frame inspection video analysis,forms the inspection video anomaly detection technology of coal mine main transportation,and applies it to the inspection robot system,the fault detection rate is improved.The intelligent control system of main coal flow transportation is designed,which realizes the intelligent speed regulation based on coal flow tracking and the one-button coal-flow startup function.The visual detection technology of conveyor belt tear based on vision and lidar fusion and the state monitoring and fault diagnosis technology based on voiceprint analysis of belt conveyor improve the stability of the main transportation system.

In order to study the mechanism of roof separation inside and outside the anchorage area of soft rock roadway,Taking the air return roadway of 50213 working face in Guantun Coal Mine as the engineering background, based on the principle of superposition method, the mechanical model of the inner and outer roof separation of the anchor cable anchoring area of the soft rock roadway is established. The calculation formula is used to analyze the influence law of the amount of roof separation inside and outside the anchor cable anchoring area, and the influence degree of each factor is determined. Through similar simulation, the evolution law and reason of the separation of the roof inside and outside the anchoring area of the anchor cable are analyzed, and the "inverted trapezoidal" support technology of high pretension long cable is proposed, and the control effect of surrounding rock is carried out by numerical model. The simulation results show that the plastic zone of surrounding rock is significantly reduced after optimization, the maximum subsidence of the roof is reduced by 50.7% compared with the original plan; The problem of roof separation ensures the stability of the surrounding rock of the roadway.

In order to determine the reasonable relocation step distance for vertical mining of inclined coal seams, with an open-pit mine in Xinjiang as the background, the shortcomings of the current situation of the relocation of the inclined coal seam crushing station were revealed, and the direction of improvement in the research on the removal of crushing stations was explained. , The impact of the layout of the double crushing station on the open-pit mining, through the method of equalizing the cost of the moving step of the crushing station and adding the influence factors of the vehicle's heavy load up and downhill, a multi-step mathematic model of the moving freight for the vertical mining crushing station is constructed. Established a general formula for the displacement step distance of the vertical mining crushing station in inclined coal seams, verified the rationality of the general formula, and proposed two dual crushing station end-side layout and displacement schemes, and analyzed the advantages and disadvantages of the two schemes to select the best According to the optimal layout and relocation plan, using the mining parameters of an open-pit mine and referring to the indicators of other open-pit mines, the reasonable relocation step distance of the two crushing stations in the end-side vertical mining relocation is calculated. Verify the rationality of the layout of the belt conveyor when moving between the steps of the end of the double crushing station.

Aiming at the frequent gas overrun in upper corner during fully mechanized mining face mining, the surface mining well was used for gas extraction in the fracture zone of the mining area. Based on the theory of “O” shaped circle formed after the mining and the experience of other mining wells in Qinshui Basin, the optimal layout of mining wells is determined. The test results show that the horizontal level is 42 m away from the side of the air return roadway, and the vertical level is 22 m from the end of the drilling to the bottom of the goaf. After the operation of the mining well, the gas concentration in the upper corner decreased and stabilized to 0. 35% from 0. 76%, and the gas emission from the working face was 2. 08 m³ / min lower. In addition, the continuous extraction during and after mining was realized. The high efficiency extraction of the mining well effectively ca eliminate the gas overrun in the fully mechanized mining face, and the promotion and application in Yuecheng Mine can provide a solution for gas control in other similar mines.