In view of the determination of the width of narrow flexible formwork concrete roadway beside gob-side entry retaining in shallow seam, this paper takes the 15301 working face of Wujiagou coal mine of China Coal Science and Technology Group as the engineering background, the method of combining numerical simulation, theoretical calculation and engineering example is adopted to carry out the research. The results show that when the width of flexible formwork wall is more than 1.5 m, the stress concentration of wall and surrounding rock, the deformation of roadway surrounding rock tend to be stable, and the stability of roadway surrounding rock is better. Considering the economic safety benefit, the 1.5 m wall width is selected as the construction condition. The engineering application result shows that the flexible formwork concrete technique can fully ensure the roadway surrounding rock stability, and the roadway side support effect is remarkable, to improve the safety of the mine as a whole, the technology of retaining gob-side entry with flexible formwork support has a good prospect of popularization.

Coal resources in some mining areas in Shanxi Province are decreasing year by year, and some old mining areas face the risk of resource depletion. In order to prolong the service life of the mine, taking the 15202 working face of Fuda mine in Shanxi as an example, the feasibility of improving the resource recovery rate was studied from the perspective of roadway layout. According to the mining conditions of the working face, the technical schemes of small coal pillar support lane, gob-side retaining wall and along the empty lane are designed respectively, and each scheme is analyzed from the aspects of technology, safety and economy. The results show that: small coal pillar protection The roadway has the lowest implementation difficulty, less investment and quicker results, better safety, but the lowest long-term benefit; small coal pillar support lane is restricted by the construction of roadway expansion, so the short-term benefit is low, but the safety is the highest; along the empty lane is affected by roadway expansion and return air the impact of system construction, the short-term benefit is the lowest, the secondary reuse and maintenance of the roadway is more difficult, but the long-term benefit is the highest. Considering that the two schemes of gob-side retaining wall and gob-side entry retaining seriously restrict the overall benefits of the mine in the short term, the 15202 working face adopts the small-pillar mining technology, and the gob-side retaining wall arrangement is changed after the tension of the excavation is relieved in the later stage.

Based on the engineering background requirements of gas extraction and gangue treatment in a mine in Yunnan, a complete set of in-situ filling mining technology for protective layer suitable for gas pressure relief in close-distance coal seam group was proposed. The main principle and design process were expounded, and the key parameters of in-situ filling mining method for protective layer were analyzed. The floor failure depth and equivalent mining height were theoretically calculated, and the filling height of protective layer was designed. The rock failure effect, stope pressure relief effect and protective layer expansion and permeability enhancement effect under the parameters of this group were verified and analyzed by numerical simulation. The results show that the simulation results under the condition of this group of parameters meet the requirements of the regulations. This technical method realizes the efficient and safe mining of coal resources in close-distance coal seams, so as to promote the development of in-situ filling technology of protective layer and provide engineering and technical reference for other mines.

Based on the “support-unloading” combined technology for gob-side entry retaining, establishment mechanics model for buried height working face of SanJiang coal mine. Pressure relief height and roadside support strength obtained by theoretical calculation method, and used in industry application. The results showed, end support resistance decreased by 12% after hydraulic fracturing, the maximum load of pillar reached 27.9MPa without damage, which proved that 1m concrete pillar support strength fitted shallow buried height working face with 92m depth and 5.24m height mining. The moving quantity of roof and floor was 83mm, the maximum roof abscission layer was 23mm during gob-side entry retaining period. It can provide technical reference for mining without pillars under similar conditions.

In the planning system for the execution of EPC projects, the schedule plan is one of the top priorities of project management, and a reasonable and scientific schedule plan is the premise to ensure that the objectives of the EPC project can be achieved. The schedule plan compiled by combining the manhour schedule and cost weight can more graphically, scientifically and accurately reflect the actual executed progress and cost control of the project simultaneously. This paper analyzes the schedule preparation method, gives how to combine the project contract, execution plan and manhour weight for schedule preparation, and discusses the advantages of this monitoring system。

The serious deformation and breakage of roadway surrounding rock and the easy failure of the anchoring structure under mining in isolated working face of thick coal seam are the urgent issue which need to be paid more attention in the multiple seams by repeated mining. Based on this problem，the ZF303 transport tunnel of Xiagou Coal Mine is taken as test road-way.Then it determines the main factors affecting serious deformation on surrounding rock of transport tunnel trough surrounding rock analysis and on-site drilling monitoring. It has proposed the combined support technology of "anchor net cable + steel belt + metal net + grouting" to reinforce the channel on site, and proved the feasibility by Flac3D software simulation. The field monitoring results show that the maximum deformation of roof, floor and two sides in the tunnel grouting reinforcement section is significantly reduced compared with that in the unrepaired tunnel, Furthermore, the cracks in the surrounding rock are almost filled by grouting material, and the overall stability of roadway surrounding rock is completely achieved.

In order to solve the problem that the gob-side entry retaining under short distance goaf is affected by multiple mining and the surrounding rock of the roadway is seriously deformed, taking the engineering geological conditions of gob-side entry retaining in 1304 working face of Xiangyuan coal mine 3# seam as the background. Using numerical simulation and theoretical analysis, the stress distribution law of the floor strata in the goaf of the upper coal seam and the deformation and failure characteristics of the roadway in the lower coal seam are studied. The surrounding rock control countermeasures of the gob-side entry retaining under short distance goaf are determined. The asymmetric coupling control technology of “roof grouting long anchor cable reinforcement + solid coal wall and roof high-strength and high preload bolt + strong single hydraulic pillar in the roadway + flexible formwork concrete wall tie rod reinforcement supplemented by single pillar protection wall” is proposed. The engineering practice results show that the developed surrounding rock control technology has a significant control effect on the surrounding rock of the gob-side entry retaining under short distance goaf, and effectively limits the crushing and subsidence of roof and the lateral extrusion deformation of narrow flexible formwork concrete.

In order to solve the problem of large scale deformation and failure of the underground chamber group in Zhangcun Coal Mine, the stress distribution and deformation characteristics of the group were studied by numerical simulation. The results show that the main contributing factors of deformation and failure are low rock strength and roadway interaction. Because of low rock strength，a plastic zone with a width of 1.5 to 2 times of the roadway is formed around the chamber. Under the influence of roadways, the large scale plastic damage area produced by the connection of plastic zones is the root of deformation and damage of the chamber group in the bottom hole. According to the research conclusions, a roadway repair plan was proposed, and well application effects are achieved in the field through the use of full-length prestress grouting cables.

Aiming at the problems such as serious bottom heave and difficult roadway maintenance in No. 1 coal centralized roadway in Danhou Mine, combined with the field measurement data, based on the Mohr-Coulomb strength criterion, the distribution characteristics of in-situ stress field are obtained by inversion method; Method to determine the disturbance scale between the roadway and the coal seam; according to the actual situation of the mine, analyze the mechanism of the roadway heave and determine the type of heave; based on the supporting principle of key parts, a reasonable support scheme is proposed. The numerical simulation results show that the optimized support scheme effectively controls the deformation of the surrounding rock and the heave, and the integrity of the surrounding rock is significantly improved to ensure the safe production of the mine.

In order to solve the deformation problem of dynamic pressure roadway under the influence of thick and hard roof, this paper comprehensively studies the directional presplitting roof cutting pressure relief technology and its key parameters, including roof cutting angle, height, blast hole charge and spacing, by using the research methods of theoretical analysis, numerical simulation and engineering test. Based on the engineering geological conditions of the test face in caojiatan mine, the numerical simulation and field test of roof cutting and pressure relief are carried out, and the reasonable parameters of roof cutting and pressure relief are determined. The research results show that under the condition of directional blasting roof cutting, the deformation of dynamic pressure roadway can be effectively controlled, the bottom heave of the first two supports can be reduced by 50%, the bottom heave of the last four supports can be reduced by more than 91%, and the surrounding rock deformation of thick and hard roof roadway can be effectively controlled.

Yuanbaoshan open pit coal mine is covered by the Quaternary aquifer with strong water abundance formed by the alluvial and proluvial deposits of Yingjin river. In order to protect the ecological environment and groundwater resources of the mining area and reduce the drainage water, it is proposed to adopt the water interception curtain dominated by underground diaphragm wall and supplemented by drilling grouting to intercept the Quaternary aquifer with a fully closed curtain from the aspects of geological conditions, construction technology The feasibility of water cut-off curtain is studied from four aspects: water cut-off effect and economic benefit. The results show that the strength of rock is generally below 10MPa, the permeability coefficient of Quaternary aquifer is 123 ~ 637m/d, and the permeability coefficient of curtain base is less than 0.08m/d, which is allowed by geological conditions; The maximum depth of water cut-off curtain is 75m, and the construction technology is mature; The numerical simulation results show that after the formation of water cut-off curtain, the Quaternary make-up water of the pit decreases by 79.8%, and the water cut-off effect is obvious; The investment recovery time of the project is only 5.04 years, and the economic benefit is remarkable. The water cut-off curtain can fundamentally solve the environmental protection risks, potential safety hazards and economic burden caused by large-scale drainage in Yuanbaoshan open pit coal mine.

Abstract：Taking 42204 working face of bultai coal mine as the engineering background，using theoretical analysis and field test, the mechanism of abnormal ground pressure and application of prevention technology during the working face passes through the coal pillars are studyed. The results show that: The theoretical minimum mining height without instability of the roof of the overlying working face is 10.32m, Through theoretical calculation, the minimum collapse height required to fill the goaf is 31m, Combined with the occurrence characteristics of rock stratum, the reasonable fracturing horizon is calculated, The hydraulic fracturing scheme of "directional long drilling in working face + along slot shallow hole" is put forward. The results of ground pressure monitoring data show that the length of periodic pressure on the roof decreases, The goaf can be enriched by caving roof rock blocks, the maximum subsidence of the roof in the triangle area of the tail of the working face is 200mm, The maximum subsidence of the roof of the return air roadway is 80mm,The maximum approach of two sides is 150mm, The application results show that hydraulic fracturing can weaken the integrity of the roof, The ground pressure of working face in the area affected by coal pillar is reduced.

For multilayer hard roof roadway in coal face of close distance coal seam mining in high stress state when the problem of difficult to maintain, taking the close coal seam of Ximing Mine of Shanxi Coking Coal Group Company as the research object, combining the theoretical analysis and numerical simulation, proposed under the condition of hard roof close distance coal seam mining eliminated by cutting roof pressure relief method of roof overhang structure, The influence of cutting roof position and pillar width on the stress and stability of roadway surrounding rock is studied. The results show that when the coal seam with multi-layer hard roof is mined in close distance, after the upper coal seam is mined, there is a large span suspended roof structure with unfavorable surrounding rock stability in the roadway of the lower coal seam. Reasonable cutting roof position can effectively eliminate the influence of suspended roof effect on the stress distribution of surrounding rock in the lower coal seam roadway. The width of the upper coal pillar affects the deformation rate of the surrounding rock of the lower coal seam, and the width of 30m coal pillar is the critical cut-off point of the deformation rate of the surrounding rock of the roadway.

In order to solve the problem of lagging behind in the monitoring and early warning of large-area supports disaster caused by sudden cutting roof of shallow-buried working face, the analysis of mine pressure data measured on the shallow-buried working face and the simulation test method of similar materials are used to study the characteristics of shallow buried deep working surface from the aspects of resistance increase characteristics of support work resistance, evolution law of rock overburden strain, and relationship between rock cover strain and roof breakage pressure. The results show that the working resistance of shallow-buried working face is slightly increased at the time of non-pressure, and the resistance increase rate is increased by 27-85 times when the pressure is coming, which reflects the mutability of the overburden strain; the micro-strain of the overburden rock before the top plate is pressed, the overburden strain suddenly increases when the pressure is pressed, and the spike occurs when cutting the top; the overburden strain has sensitivity and advance, which can monitor and warn of the abnormal pressure of the roof plate. In addition, a site monitoring and early warning method for distributed fiber optic technology based on strain (displacement) index is proposed. The research has practical value for the prevention and control of roof disasters in shallow-buried coal mining.

Aiming at the problem of health damage caused by exhaust pollutants of explosion-proof diesel trolleyless wheelbarrow in underground coal mine, an online monitoring system for the exhaust of explosion-proof diesel trolleyless wheelbarrow in underground coal mine was designed for real-time monitoring of vehicle exhaust. The system is composed of sensor nodes, coordinators and monitoring hosts. Wireless communication channels are established by LoRa, 4G, 5G and other wireless communication technologies. The coordinators gather sensor node data and then forward the data to the monitoring host. After the test, the system communication quality stability monitoring of high precision, satisfy the real time monitoring of coal mine underground space environment rubber_tyred car explosion-proof diesel engine exhaust emissions, provide real-time data for coal mine, direct control of ventilation system and vehicle scheduling plan, reviewing the status of vehicle emissions, and improve the workers work environment, reduce the occupational disease risk, safeguard worker health.

In view of the maintenance difficulties caused by dense roadway, weak rock column and strong mining influence in deep panel, the application research of "unloading control coupling" advanced control technology is carried out for 1305 (upper) working face of Hudi coal mine and its corresponding panel roadway. When the cutting height is 30m, the reasonable cutting position is 30m ahead of terminal mining line location through numerical simulation, and the cutting construction technology of deep hole blasting is given. At the same time, the zoning coupling advance reinforcement control technology is adopted to strengthen and support the main roadway in the panel through 7.3m and 5.3m long medium length anchor cables and 10.3M long anchor cables, together with No. 20 high-strength trough steel beam and reinforcement mesh, so as to enhance the overall firmness of the surrounding rock of the main roadway in the panel. After the application of "unloading control coupling" advanced control technology in panel roadway, the deformation of surrounding rock of lane 1103 is greatly reduced, the stability of surrounding rock is significantly improved, and the reliability of support structure is guaranteed.

In the process of top coal caving intelligently, how to find the environment states and the action decision mechanism is the key to control the window behind the hydraulic supports. This paper extracts the actions of the top coal caving as a Markov decision process by the spatial layout of the hydraulic supports and the characteristics of the windows action. Meanwhile, the reinforcement framework learning is employed to determine the optimal action of windows when top coal caving, in which the Q-learning algorithm is adopted online to learn the mapping between the state of top coal and the action of the windows without preparing huge training samples. In the methodology, a new reward function based on mean deviation is designed for Q-learning to maintain the coal-rock boundary settlement uniformly when top coal caving. In the top coal caving dynamic process, the agents are guided by the reward function to learn how to control the shape of the coal-rock boundary, therefore the action coordination of the agents is reinforced to improve the effectiveness of the top-coal caving. Finally, a three-dimensional simulation experiment platform based on YADE discrete element analysis method is created in the Linux system, and the effectiveness of the proposed methodology is demonstrated by the experiment of cutting the coalface continuously. The experimental results show that the coal-rock boundary driven by our method is flatter during the coal falling, and the average reward of the agent for top coal caving can reach 13467.8. The reward of our method is 8.8% higher than the Q-learning method and 10% higher than the single-round sequential coal caving process.

In order to quantify the damage and failure process of soft coal body, for the coal body in Huainan mining area, using briquette instead of raw coal, the monitoring test of acoustic emission characteristics of coal body under compression is carried out, and the damage variable D is defined by cumulative AE counts. The damage evolution characteristics of coal body are studied. With the increase of axial strain, the damage variable of coal body shows a trend of stable, slow growth, rapid growth and then stable. The expression of coal constitutive relationship is deduced, and the rationality of the theoretical constitutive model is verified. The total stress-strain curve obtained by the theoretical constitutive model is consistent with the test results. The average absolute error between the theoretical stress value and the test value is only 0.126mpa, which realizes the theoretical description of the stress-strain relationship of soft coal. The research results can provide experimental and theoretical basis for revealing the mechanical response characteristics of failure and instability of soft coal and preventing and controlling instability disasters.

The exhaust gas emitted by vehicles in idling underground chamber of coal mine seriously threatens the occupational health of coal miners. Taking the 25211 working face chamber of Hongliulin Company and the WC19R(A) rubber-tyred truck as the research objects, a component transport model was constructed based on the Euler method, simulated and analyzed the diffusion characteristics of NO, NO2 and CO exhaust gas in the tunnel under the influence of different roadway wind speeds. The results show that: when the wind speed exceeded 1.0 m/s, due to the increase of the wind speed in the roadway, the exhaust gas was affected by the lateral vortex in the chamber, and the phenomenon of diffusion to the chamber mouth was gradually significant; the gas followed Fick's law in the process of diffusion, and the exhaust gas concentrations on both sides reached their peaks at about 9.0m and 1.0m from the chamber mouth, respectively, and the fitting functions of the three gases were obtained at the same time. After on-site verification, the error between the simulation results and the on-site test results is less than 23.7%.

Low-temperature pyrolysis of tar -rich coal to produce tar is a way of clean and efficient utilization of coal resources. This paper studies the influence of tar-rich coal production area(Zhangjiamao, Ningtiaota, Hongliulin), particle size, final pyrolysis temperature, heating rate, pressure and different industry analysis of tar-rich coal on tar yield. The quality of tar is analyzed by gas chromatography simulated distillation. The results showed that under the conditions of particle size of 0.8-2mm, final pyrolysis temperature of 550℃, pressure of 0.1Mpa, and heating rate of 26℃/min, Zhangjiamao's tar-rich coal has the largest tar yield of 13.19%. The yield of tar increases with the increase of volatile matter, hydrogen content and H/C of tar-rich coal.

ased on the difficulty of gas drainage at the initial stage of mining in the first mining face, the deformation and pressure relief of the roadway and surrounding rock formations after the construction of the borehole are analyzed, and the model of the double pressure relief ring of the borehole and the roadway is established to calculate the gas pressure at any point between the borehole and the roadway. According to the gas stress, the gas flow quality equation at this point is obtained, so as to propose the gas extraction plan of the downhole drilling in the high suction tunnel, and put forward corresponding countermeasures for the drilling problem of the downhole drilling, and finally the first mining work in 1301 is carried out. Engineering tests are carried out. The research results show that the gas extraction time is 10m ahead of the initial pressure step; there is no gas over-limit or power outage during the mining of the working face. Therefore, the downward drilling gas drainage scheme in the high-drainage roadway solves the gas over-limit problem in the initial mining face, which proves that the drilling-roadway double pressure relief ring model is reasonable and feasible. The gas management of the surface is of guiding significance.

In order to solve the problem of environmental pollution caused by dust in mine, By orthogonal experiment, the dust removal mecha-nism of vibration fiber grid and high-pressure spray of vibration exciter was studied. The effects of vibration frequency, fiber filling rate, spray amount, wind speed and other factors on the dust removal efficiency and purification resistance of vibration fiber grid of vibration exciter were analyzed by orthogonal experiment, and the optimal parameters of vibration fiber grid of vibration exciter were determined by experiment. The wireless infrared automatic control system is designed, and the automatic control dust removal technology of vibra-tion fiber grid of vibration exciter based on high-pressure spray is developed. Experiments show that the continuous operation of the vibrating fiber grating system of the exciter has a dust removal efficiency of over 93%.

Coal mining in the northern Shaanxi mining area poses a certain threat to the geological environment, causing damage and degradation of land resources. Land reclamation of damaged land and improvement of land utilization are important contents in the construction of green mines in the mining industry. Based on the analysis of its natural geographical features, hydrological climate, vegetation, and land use types, this article takes the Caragana mine area as the research object, studies the characteristics of land reclamation in this area, and analyzes the links and forms of land damage in the mining area. Based on the comprehensive analysis method, Through the division of land evaluation units in the study area, the suitability of land reclamation was further evaluated, the main evaluation factors of the study area were comprehensively considered, the final reclamation direction was obtained, and the appropriate reclamation measures for each reclamation unit were proposed. Research on land reclamation in fragile mining areas has important guiding significance.

Coal preparation/mining can reduce the ineffective or harmful components of raw coal such as ash, sulfur and heavy metals. The resulting changes in mineral and organic components may affect the pyrolysis process and its kinetics, which is rarely reported in the literature. Raw coal from Shendong Coal-to-Liquid Coal Preparation R-YL and clean coal C-YL obtained from coal washing process were conducted pyrolysis experiments in TGA. The temperature was from room temperature to 1100°C, and the heating rate was 5, 10, and 20 K/min. The effects of coal preparation (coal washing) on the pyrolysis behavior of low-rank coal were studied. The results showed that the ash content of raw coal decreased from 9.12 to 4.69 wt.%, and the index of basicity changed from 1.92 (high alkalinity) to 0.68 (acidity). However, the organic components represented by functional groups were not changed a lot. In the primary pyrolysis stage (300～550℃), the maximum weight loss rates Dmax1 of clean coal pyrolysis at different heating rates were slightly lower because the washing reduced the catalytic performance of minerals. In the high-temperature pyrolysis stage (550～700℃), the maximum weight loss rates Dmax2 of raw coal were slightly higher at different heating rates, because most of the calcite removed from coal washing will be heated to decompose to CO2, which increased the weight loss rate.

During the mining process, the coal and rock are regarded as normal working loads, the gangue and faults being regarded as random shock loads. The pick can be affected by natural wear and tear caused by the coal and rock and load shocks caused by the gangue and faults—that is, the result of the competing influence of soft failure caused by natural wear and tear and hard failure caused by random load shocks. Because the gangue and faults have a certain volume and hardness, a random load shock may last for a certain period of time, producing different acceleration effects on the pick wear under different hardness. The degradation model of pick competing failure under random load shocks was established by considering the natural wear degradation, instantaneous shock degradation, and accelerated degradation at changing rates during shock periods. The results showed that the competing failure degradation model of the pick considering continuous shocks and a changing degradation rate was more in line with engineering practice, which provides a theoretical basis for pick reliability assessment, maintenance decision and spare parts management.

In the automatic production line of mine anchor rod, the traditional anchor feeding system mostly transforms the rotary motion into linear motion through the intermediate transmission system (chain drive, gearbox, ball screw, etc.) with some problems, such as low efficiency,large noise, low control accuracy, large mechanical loss and large maintenance quantity, therefore the permanent magnet direct drive feed system is put forward. it generates direct thrust through the primary and secondary electromagnetic induction, eliminating the intermediate drive, and it has some advantages, such as compact structure,fast reaction speed, high control accuracy, small working noise, small maintenance amount and so on, the problems of high noise and high fault rate are solved. Due to the permanent magnetic direct drive system is susceptible to external perturbations and nonlinear effects, and is more sensitive to external perturbations, it brings some difficulty to the study of system control strategies.Therefore, this paper studies the control strategy of permanent magnetic direct drive system through theoretical analysis and simulation, the result show that the vector control system can obtain stable speed and thrust response, but large overregulation and thrust fluctuations; the variable structure control model has good tracking performance, with the advantages of fast response, no overregulation, robustness and small thrust fluctuation.

This study calculates the provincial carbon emission efficiency along the Belt and Road in China from 2013 to 2017 based on the Super-SBM-undesirable model, the spatial Dubin model is used to investigate the spatial influencing factors and spillover effects of provincial carbon emission efficiency along the line. Our results show that: (1)The carbon emission efficiency of provinces along the line is low and shows obvious geographical differences. (2)The carbon emission efficiency of provinces along the line shows a non significant positive correlation with the technical level, while the economic growth, energy structure and industrial structure show a significant negative correlation. (3)By decomposing the total effects, we find that the positive spatial diffusion effects of carbon emission efficiency of provinces along the line come from technical level factors, and the spillover effects of economic growth, industrial structure and energy consumption are the main reasons for the decline of carbon emission efficiency in adjacent areas.

Coal is the main energy and important raw material in China. Whether coal enterprises can create value and sustainable development will be related to China's energy security. In order to promote the high-quality and high-efficiency development of coal enterprises, the characteristics of coal enterprises with good performance is analyzed and discussed by comparative analysis and questionnaire, and then a characteristic index system of coal enterprises with good performance is conducted from the three-dimensional perspective of input factors, process management and business development effectiveness. The system contains 21 secondary indicators such as resource endowment, technology, facilities and 46 tertiary indicators such as coal quality and geographical location. Finally, the established characteristic model is applied and tested based on the relevant data of Shaanxi Coal and Chemical Industry Group Co.,Ltd.，and its valuation results are analyzed and discussed.