Abstract：In view of the difficulty of soft mining of large dip angle coal seam in Yimen Coal Mine, the technical parameters of hydraulic support, shearer and conveyor in working face are calculated by analyzing the mining characteristics of steeply inclined unstable extra-thick coal seam, and the ' three machines ' equipment in working face is selected and applied in engineering. The results show that the horizontal section working face of Yimen Coal Mine should choose the top coal caving hydraulic support with flexible, lightweight and good sealing performance, short fuselage shearer and conveyor matching with mining and caving capacity. It is calculated that the working resistance of the support is not less than 1920 kN, the actual power of the shearer should be 94 ~ 109 kW, the transportation capacity of the front scraper conveyor should not be less than 300 t / h, and the rear conveyor should not be less than 952 t / h. The ' three machines ' selection results of the working face were applied to the 1212 working face of Yimen Coal Mine. During the field observation period, the operating rate of the shearer reached 60 %, and the working resistance of the support met the roof control requirements. The shearer cut coal and top coal caving process worked in parallel, achieving high yield and high efficiency.

In order to solve the problem that traditional shaft lining design theory cannot reasonably calculate the shaft lining of a shaft with a depth of more than one kilometer, take the shaft lining design of an auxiliary shaft with a depth of 1341.6 meters in Cixi Mine as the engineering background. Through analyzing the mechanical mechanism of the shaft lining and surrounding rock, a unified mechanical model is incorporated into the shaft lining and surrounding rock, and the water and soil coupling mechanism is introduced to establish a mechanical model for the solid-liquid coupling action of the shaft lining and surrounding rock. Based on the thick wall cylinder theory and the third strength theory, the theoretical formula for calculating the thickness of shaft wall under the joint load of shaft wall and surrounding rock is obtained. According to the theoretical expression of joint bearing capacity of shaft wall and surrounding rock, the factors, the factors that affect the reasonable thickness of shaft wall include physical and mechanical parameters such as compressive strength, elastic modulus, shear modulus, Poisson's ratio, and water content and permeability pressure of rock strata. Using this theory, the wall thickness of the auxiliary shaft in Cixi No.1 Mine was calculated: the reasonable thickness of the mudstone section (buried depth 1280m) was calculated as 0.852m, and the design value was 0.9m; The reasonable thickness of the shaft wall in the sandstone section (buried depth 1200m) is calculated as 0.747m, and the design value is 0.8m. Since the design, construction, and use of the shaft, the shaft wall has been in good condition, meeting the needs of safe production. The engineering application shows that the joint bearing theory of shaft wall and surrounding rock and the expression of shaft wall thickness meet the safety design requirements for shaft walls in ultra kilometer deep wells.

The underground intelligent separation technology and equipment is an important part of intelligent construction of coal mine, and it is also an urgent link for coal mine enterprises to further promote the construction of green mine. The current development status of intelligent dry coal and gangue identification technology is summarized, and the current stage achievements of the application of underground intelligent dry separation technique are introduced. The basic principles of underground intelligent dry separation process layout are discussed: compact, intelligent, modular and integrated, and the key factors that restrict the development and application of its equipment are analyzed: distribution uniformity, identification efficiency and dust harmlessness. Finally, the trend of its development is forecasted from social and economic benefits.

"Peak carbon dioxide emissions、Carbon neutrality" is a two stage carbon emission reduction goal proposed by China, and carbon emission accounting is the basic premise for effectively carrying out various carbon emission reduction work and promoting green economic transformation. The coal industry is one of the key objects of carbon emission reduction. Taking Heidaigou Coal Preparation Plant as the research object, based on IPCC greenhouse gas accounting guidelines and China's coal production enterprise accounting guidelines, this paper studies the carbon emissions in the production process of the coal preparation plant and the selection of carbon emission factors, builds a carbon emission accounting model of the coal preparation plant, and calculates that the carbon dioxide equivalent of the production of 1t coal products of the coal preparation plant is 36.8476kgCO2e, It is of great significance to establish a unified and standardized carbon emission accounting system for the coal preparation industry, coordinate the " Peak carbon dioxide emissions、Carbon neutrality " work, and promote the overall green and low-carbon transformation of economic and social development.

The prestressed arched tube truss structure has the advantages of strong spanning ability, superior structural mechanical properties and large coal storage capacity, and has been gradually applied to large-span coal sheds.The coal shed support of large-span prestressed pipe truss structure bears large forces, and most of the support joints adopt hemispherical joints. The relevant specifications do not specify the specific method of checking the large-diameter hemispherical joints, and domestic scholars have done research on cast steel and welded hemispherical bearing joints respectively, but there is no research on the joints connected with large diameter bearing welded hemispheres and branch pipes and their reinforcement methods.. In this paper, the finite element simulation software MIDAS FEA is used for linear and nonlinear analysis. In the linear analysis, the stress concentration is obvious in a small local area and the stress in other areas is small, the calculation result is distorted, and a nonlinear analysis is required.The bearing capacity of the joint can be improved by adding cross ribs in the hemisphere and stiffening ribs outside the branch pipe with small diameter. The nonlinear analysis of stiffener joints with different thicknesses is carried out. When the stiffener thickness is equal to the wall thickness of the reinforced branch pipe, the bearing capacity of the joint has a certain safety reserve and is more economical and reasonable.

Aiming at the problem of large deformation of gob side entry retaining surrounding rock caused by unreasonable roof cutting parameters in the double layer close distance hard strata. Through in-situ monitoring, theoretical analysis and discrete element numerical simulation, taking the 090109 headentry of Baigou Coal mine as the project background. The characteristics and mechanism of ground pressure behavior of gob side entry retaining with the double layer close distance hard strata are expounded. The necessary conditions for maintaining the stability of roadway surrounding rock are analyzed. The reasonable roof cutting height, cutting angle and roof strengthening support technology are put forward. The results show that the synchronous bending and sinking of the double layer close distance hard strata in the goaf is the main reason for the large deformation of the gob side entry roof and floor. Roof cutting not only weaken the role of the transmission force from the goaf roof to the gob side entry surrounding rock, but also increase the crushing expansion space of the interlayer soft rock, and increase the support strength of the upper hard stratum. It is a necessary condition to control the roadway surrounding rock stability that the collapse of interlayer soft rock strata after roof cutting can fill the goaf. Based on the actual conditions, it is determined that the cutting height and angle of 090109 headentry are 6m and 15° respectively. Compared with the original roadway surrounding rock control scheme, the in-situ monitoring show that the roof and floor displacement is reduced by 35.3%, solid coal wall displacement is reduced by 49.9%, and the surrounding rock stable distance behind the working face is reduced by 55.2%, after combining the roof anchor cable reinforcement support technology. The research results provide a feasible basis for the roadway by roof cutting in the double layer close distance hard strata.

Aiming at the problem of the slow progress and low efficiency in preparation area rock system, which adopted blasting excavation method, Based on the field analysis, 7 main factors affecting rock roadway footage were obtained, 5 types were divided and the influence weight was analyzed. Combined with the rock breaking mechanism and process of bidirectional shaped charge blasting,a new shaped charge tube device was proposed,on this basis,the two step cutting scheme was designed, the borehole parameters, borehole layout and borehole charge were optimized respectively, the bidirectional shaped charge blasting technical was formed and applied in field.The application results showed that this technology had the advantages of less drilling, good effect, fast gangue production and low cost. It not only ensured the forming of the surrounding roadway, but also improved the footage efficiency. The monthly footage increased from 48 meter to 81 meter, Compared to the maximum monthly footage with previous blasting techniques, the footage efficiency increased by 68.8%, The fast construction of hard rock roadway with large section was realized, and the construction cost was saved. It can provide reference for roadway construction under the same geological conditions.

In order to solve the problem of difficult support of inclined roof and low tunneling efficiency in large inclined inverted trapezoidal roadway in Great Wall No.6 Coal Mine, by studying the geological conditions and surrounding rock conditions of coal seam in Great Wall No.6 Coal Mine, the suspension rail wing type hydraulic bolt drill rig is introduced for the first time, and the cantilever road-header is used for tunneling construction. Compared with the original artificial roadway excavation support efficiency and footage, and based on the field situation and the performance of the bolt drill rig, the temporary support platform of the drill rig is upgraded and optimized by numerical simulation. The specific conclusions are as follows: The roof of 1901 S return airway is argillaceous limestone, and the integrity of surrounding rock is good, which can meet the use conditions of anchor drilling truck. The anchor drilling truck walks in the upper space of the section, and is staggered with the cantilever road-header. The hydraulic system of the temporary support platform fits the inclined roof well and can complete the support task of the special section. The efficiency of anchor cable construction is improved by more than 60 %. In the field industrial operation, the average monthly footage of roadway excavation and support of anchor drilling truck can reach 350 m, far exceeding the original manual mode. According to the practical application and numerical simulation analysis, it is found that the hydraulic cylinder of the temporary support platform is divided into two directions of lifting and turning angle control. The pressure bearing effect of the temporary support platform of the drilling rig is better, which greatly reduces the probability of stress concentration in the structure. The structural displacement of the key parts is reduced by 63.72%, which provides a valuable reference for the application and optimization of the support equipment in the special section form of roadway excavation.

Based on the demand of mine water disaster prevention and control in Wumeng Mountain area, the local red clay is used as the grouting material for water plugging, and the grout properties of red clay cement slurry was studied. Results of the laboratory test shows that the viscosity and plastic strength of red clay cement grout are positively related to the added cement and structural additives, and the mixing ratio of red clay cement grout suitable for shaft water sealing was determined. Through infrared spectrum analysis, it was found that the hydration products of red clay cement grout mainly include ettringite, Ca(OH)2 crystal and C-S-H gel. In addition, the SEM tests revealed that structural additives can significantly promote the early hydration process of red clay cement slurry, which can significantly improve the microstructure compactness and stone rate of slurry. Finally, the red clay cement slurry material has been successfully applied in the pre-grouting project of the blind shaft of line 112 in Maoping Mine, and the water sealing rate was 98%. The red clay cement grout can effectively fill the water-conducting fractures which indicating that the red clay cement slurry has good groutability and excellent water plugging performance. Results of this paper have great reference significance for mine water disasters prevention and control in Southwest China.

Taking the withdrawal passage of 22311 fully mechanized working face in Huojitu Well of Daliuta Coal Mine as the research background, theoretical calculation and FLAC3D numerical simulation software were used to analyze the critical instability width of the withdrawal passage coal pillar, which is about 4m; The length of "long key block B" is about 21m. The structural mechanics model of "long key block" on the roof of the withdrawal passage is established, and the expression of the critical resistance of the hydraulic support under the action of the maximum "long key block" in the fully mechanized mining face is derived. The critical resistance of the hydraulic support is 10526kN, and the margin coefficient of the critical resistance of the support (rated resistance/critical resistance) is about 1.14; In view of the problem that the surplus system of the critical resistance of hydraulic support is insufficient, which is easy to cause severe rock pressure accidents such as adjacent support pressing, malignant roof caving (leakage) or wall fragmentation, the multi technical means of combined support with anchor cables, stoping mining to give way to pressure, reinforcement and reinforcement are proposed to jointly control the stability of the surrounding rock of the withdrawal passage, and they are used in field tests, and have achieved good control effects. This study provides a reference for the stability control of the withdrawal passage in this mine and other mines with similar conditions.

The vertical stress of mountainous areas has controlling effect on gas occurrence of the coal seam below of it. The influence mechanism of depth, stress and permeability of coal seam under mountain were studied based on the Winkler elastic Foundation beam theory and seepage theory. At the same time, the enrichment mechanism of coal seam pressurized by overlying mountain was analyzed. The results shows that: (1) There is a significant strong correlation between the stress characteristics, permeability change rule of coal seam and the change of buried depth and surface elevation. (2) Under the action of vertical pressure of mountain, the stress and permeability distribution of coal seam show significant nonlinear characteristics. The stress is the greatest under the peak and the permeability is the smallest. (3) The initial gas content value is controlled by the permeability and the stress of coal seam in the situation. Under the guidance of the research results, Kuangou Coal Mine adopts the "large-diameter pressure relief drilling + small-aperture pre-drainage drilling method, leading the pressure relief mountain overburden coal seam advance area, pre-draining coal seam gas anomaly area, coordinated long distance + short distance high Drilling gas in the mined-out area to ensure the safe production of the mine. During the mining of the working face, no large-energy microseismic events with a power of more than 6 power level occur. The gas concentration in the upper corner does not exceed 0.50%, and the gas concentration in the return air flow does not exceed 0.22%. There is no gas anomaly, which effectively solves the problems of coal seam rockburst and gas emission at the working face of the mine. The research results can provide a theoretical basis for the rockburst and gas gushing in the overlying coal seam in the mountain.

Abstract: The 'up flee down slide' of scraper conveyor in fully mechanized mining face has many adverse effects on the mining of working face. It results in poor safety exit, equipment damage and low production efficiency easily. Based on the practical experience of sliding control of scraper conveyor in 3408 fully mechanized mining face of a mine, this paper analyzes the problems exposed in the control process of scraper conveyor, summarizes the shortcomings of conventional methods such as working face adjustment, one-way pushing and adjusting support in practice, and puts forward the matters needing attention and improvement measures for the use of control methods in different environments and working conditions. The rapid control and adjustment of the scraper conveyor's 'up flee down slide' are realized by adopting the methods of short face rapid adjustment, scraper conveyor rapid flattening, oil cylinder auxiliary adjustment and so on.

In order to study the distribution characteristics of the spontaneous combustion hazard area in the goaf of the shallow buried extra-thick working face, the three-dimensional "three zones" distribution law of coal spontaneous combustion in the goaf based on oxygen concentration was studied by combining theoretical analysis, experimental tests and field observations with the working face 15304 of Wujiagou Coal Mine. The results shown that: the upper and lower limit oxygen concentration of coal spontaneous combustion in the goaf are 18.05% and 5.95% respectively. The oxidation zone on the horizontal is 45-158 m in the inlet side, and from 14-75 m in the return side. The oxidation zone on the vertical is distributed from 6 to 42m on the inlet side and from 4 to 37m on the return side. The oxide zone is asymmetrical in tendency, with the zone farther away from the lower corner of the face on the inlet side and closer to the corner of the face on the return side. In both horizontal and vertical directions, the width of the oxide zone on the inlet side is greater than the width on the return side. The minimum safe advancing speed of the working face is 1.64m/d. When the advancing speed of the working face is less than this speed, the fire prevention measures should be reinforced.

In view of the difficult problem of dust prevention and control in large mining height working face, the treatment idea of dust sourcing-zoning-classification in coal working face was proposed. Based on the field measurement analysis of dust distribution characteristics in coal working face, dust sources in coal working face were divided into shearer cutting area, hydraulic support following machine moving area, scraper conveyer transfer area and re-turn air roadway area. According to the distribution characteristics and treatment requirements of dust in different areas, the treatment was carried out by different sources, zones and stages. By optimizing the inner and outer spray design of shearer, the range and atomization effect of the spray device are improved effectively. Through the de-velopment of AAZ-LNN nozzle applied in the hydraulic support, combined with the negative pressure coil suction dust collector and direct dust devices between hydraulic supports, the dust removal effect of the hydraulic support following the machine is greatly improved. Through the development and application of geomantic linkage dust removal device, the effective prevention and control of dust at the transfer point of scraper conveyor and crusher was realized. The dust escaping from the coal face can be captured effectively by using fog curtain dust collection net device in the whole section of return air roadway. Based on the research and development and application of the above-mentioned dust source-zone-classification treatment technology equipment, the dust removal rate of to-tal dust and resizable dust of 25212 working face is increased by 40%, and the working environment of the work-ing face is effectively improved, which can provide technical reference for dust control of similar working face.

Abstract: In order to deeply study the interaction between goaf roof and gangue backfill in short wall filling face. Based on the geological data of 3211 working face in Xinyuan mine, this paper systematically studies the displacement change law of goaf roof and the mechanical bearing characteristics of gangue under the condition of filling mining by means of theoretical analysis, on-site monitoring and numerical simulation. The conclusions are as follows: the subsidence of goaf roof can be divided into free subsidence stage, constrained subsidence stage, slow increasing stage and shock stabilization stage; With the advance of the working face, the gangue filled in the goaf shows obvious strain hardening characteristics, and the final compression modulus of the gangue is 67.6mpa; The stage characteristics of the stress-strain curve of the filling gangue are obvious. In the range where the strain value is less than 0.103, the stress value is basically maintained at 0.3MPa, and then the stress value increases exponentially; The final displacement change curve along the dip range of the working face is parabolic, with the largest central area, the smaller sub central area and the smallest edge area.

Aiming at the problems of large deformation and early damage of surrounding rock in deep buried tunnel under high temperature, high pressure and high humidity environment, based on the classical Cvisc constitutive model, the constitutive model of surrounding rock considering creep damage and weakening coefficient of surrounding rock material is deduced theoretically. The rationality of the constitutive model is verified by comprehensive methods such as numerical simulation and field monitoring. On this basis, the creep range and section deformation of deep tunnel surrounding rock under dry and damp softening states are compared and analyzed. The results show that the Cvisc constitutive model considering damage and weakening coefficient of surrounding rock material can better describe the relationship between surrounding rock deformation and time in deep environment. The surrounding rock of tunnel is mainly viscoelastic deformation in creep stage. The softening state has obvious time effect on the damage of surrounding rock, which makes the creep range of damp softening state expand after 18 days compared with dry state. The change of tunnel section under dry and damp softening states is asymmetric. The change shape under dry condition is approximate deflection diamond, and the change shape under damp softening state is approximate deflection trapezoid, and the change of tunnel section under damp softening state is greater than that under dry condition.

In order to improve the cutting efficiency of the roadheader, the motion parameters of the cutting part of the roadheader are taken as the design variables, and the influence of the motion parameters such as the rotation speed and swing speed of the cutting head of the cantilever longitudinal roadheader on the cutting performance is studied. MATLAB is used to simulate the variation law of each performance parameter. Based on the analysis of a single pick load, the mathematical model of the load in each direction of the cutting head is established. According to the design space of the motion parameters given by the field experience, the objective functions of the cutting resistance, load torque, cutting specific energy consumption and cutting productivity of the cutting head are established. The linear weighting method is used to transform multiple optimization objectives into a single objective. The weighting coefficients of normal working conditions and gangue working conditions are given respectively, and the optimal configuration of cutting motion parameters is solved. The cutting performance before and after optimization is verified in EDEM simulation software. The results show that the comprehensive cutting performance of roadheader under the optimal motion parameters is better, the cutting ability and rock breaking ability are improved, the cutting specific energy consumption is reduced, the productivity is significantly improved, and the dust production is controlled to a certain extent.

The theory and technology of mine water hazard prevention and control are improving in China, but the methods of evaluating water inrush risk of coal seam roof and floor are mainly static and dynamic evaluation along the workings are shortage. According to the hydrogeological structure, main controlling factors of water inrush, water inrush disaster models and water damage type in northern and northeastern China. The relationship between the risk sources of water inrush of coal seam roof and floor and the risk of disaster caused by the three suggested criteria: water filling aquifers, water flow channels and mining disturbance, and the index system of risk sources of water inrush of coal seam roof and floor was established. The index factors (aquifers’ water pressure, stress-strain, height/depth of failure zone) that have dynamic changes with mining excavation in the index system are taken as the dynamic characteristics identification targets of water inrush hazard sources. The multi-field and multi-parameter dynamic evaluation model of water inrush risk of working area was established. The multi-field information in situ of working were collected, extracted, interpolated and input. The critical criterion of mine water inrush is proposed, it provides guidance for dynamic evaluation zoning of water inrush risk of coal roof and floor and forecasting and warning of water inrush of working area.

To study the effect of aromatic micro-crystalline structure in coals with different metamorphic degrees on thermal transport properties of coal, the lignite, long-flame coal, non-stick coal, gas-fat coal, coking coal, and lean coal were selected, and X-ray diffractometer and laser-flash apparatus were adopted to measure aromatic micro-crystalline structure as well as thermal diffusivity, specific heat capacity, and thermal conductivity at 30°C–300°C. The correlation between the parameters of aromatic micro-crystalline structure and thermal conductivity of coals with different metamorphism degrees was obtained by using grey correlation method. Results indicated that, with the deepening of metamorphism degree, the aromatic interlayer spacing of coal gradually decreased, whereas extension length, stacking height, and number of effective aromatic layers gradually enhanced. With the increase of temperature, thermal diffusivity decreased firstly and increased secondly, specific heat capacity enhanced gradually, and the thermal conductivity of coal increased slowly and then swiftly after 210°C. Moreover, the thermal diffusivity and thermal conductivity of coal with higher metamorphism was higher, while the specific heat capacity was lower, this phenomenon can be explained that the extension length and aromatic interlayer spacing of coal contributed greatly to the thermal transport change of coal. The research findings are helpful to understand the heat transport process of coal.

In view of the limitation of the applicability of a single fire prevention and extinguishing material, a new type of mine fire prevention and extinguishing gel foam material was prepared by combining colloidal material with foam material in the way of ionic crosslinking, and its thermal stability and effect of preventing coal spontaneous combustion were studied. The SDS: AES compound foaming agent with ratio of 1:1 and concentration of 0.7% was determined for follow-up experiments. Based on the gelling time and gelling state, the ratio of 0.7% gelling agent concentration and 2% cross-linking agent concentration of gelling system was determined. Then, the optimal ratio of gel foam was determined by orthogonal experiment: ratio of SDS and AES 1:1, total concentration 0.8%, gelling agent 0.65%, cross-linking agent 0.25%. The experiments of thermal stability and spontaneous combustion of retarded coal show that the temperature resistance time of gel foam is the largest. When heated at 50℃~80℃ for 5h, the moisture content is still 36.5%~88.5%. The gel foam treated coal sample enters the severe combustion weight loss stage at 462.3℃, which is 59.3℃ higher than that of raw coal sample, and the maximum weight loss rate of -0.77%/min is far less than the maximum weight loss rate of raw coal sample -0.87%/min, and the temperature increases by 12.12℃ when reaching the maximum weight loss rate. The results show that the gel foam has obvious inhibition on coal combustion and has good anti-fire performance.

In order to more effectively prevent and control the dust produced in the mining process of the underground fully mechanized working face, this paper combines the magnetic field with the surfactant, uses the experimental method to study the influence of magnetization on the performance of surfactant solution, and uses it in the spray dust reduction experiment to obtain the best magnetization strength, surfactant solution concentration and dust removal efficiency. The research results show that when the mass fraction is 0.5%, the dust reduction performance of the surfactant solution after being magnetized by a 9000Gs magnetic field is better than that of the original surfactant solution; Compared with the traditional spray dust suppression technology, the dust suppression efficiency of magnetized surfactant solution on respirable dust is increased by 38.35%, and the total dust is increased by 45.46%. The research results can provide theoretical guidance for the control of flour dust in underground coal mining work.

In order to investigate the dynamic mechanical characteristics and failure mechanism of sandstone under impact loads, the dynamic mechanical tests of sandstone were carried out by SHPB device. And the stress-strain curve, dynamic compressive strength, dynamic elastic modulus and change of absorbed energy per unit volume of sandstone were studied. In this investigation, the failure mechanism was analyzed, the failure mode and the change law of failure fragmentation of sandstone were elucidated as well. The results show that the stress-strain curve of sandstone under impact loads develops in stages, with the linear elastic rising stage, nonlinear oscillation fluctuation stage and post-peak decline in order The dynamic compressive strength, absorbed energy per unit volume and dynamic elastic modulus of sandstone are related to the impact velocity by power functions, quadratic functions and quadratic functions respectively, all of which have obvious impact velocity effect. With the increases of impact loads, the fractal dimension and fracture degree of sandstone rises and the failure mode of sandstone changes from tensile failure to tensile-shear coupled failure. The results of the study can provide a theoretical basis for the stability control of the strong dynamic pressure roadway and the surrounding rock of the stope.

Shendong mining area is a typical shallow-buried coal seam mining area，surface deformation is very severe after coal mining, and the discontinuous deformation such as cracks is very obvious. Probability integral method is applicable to the continuous deformation of the surface, so it is necessary to discuss its applicability in Shendong mining area. Probability integral method is derived from random medium theory and probability theory, starting from this, this paper calculates the relationship coefficients of probability integral method under the fully mechanized mining conditions in Shendong mining area and the Mid-East mining area respectively, and compares them with the theoretical values of the relationship coefficients of probability integral method, so as to discuss the applicability of probability integral method under the fully mechanized mining conditions of shallow coal seams in Shendong mining area. The research results show that, compared with Mid-East mining areas, the relationship coefficient of Shendong mining area not only differs greatly from the theoretical value of the probability integral method, but also has a large degree of dispersion. This shows that the applicability of probability integral method in Shendong mining area is not as good as that in the Mid-East mining area. By analyzing the factors that affect the applicability of the probability integral method, a research method based on the key stratum theory is proposed to improve the calculation method of shallow coal seam mining subsidence.

The effect of vehicle-induced seismic waves on the dynamic response characteristics of geotechnical slopes is one of the important issues in engineering construction. Taking the inner dump of Yuanbaoshan open-pit mine in Inner Mongolia as the prototype, and uses MatDEM software to construct a dynamic response model of the inner dump slope. It simulates the process of vehicle induced vibration of the slope, and analyzes the dynamic characteristics and response laws of the slope under earthquake action from various aspects such as different slope surfaces, different vertical distances, different horizontal distances, and different angles at the same distance. The results indicate that the velocity waves generated by the seismic source propagate in a circular arc, resulting in wave field disorder due to multiple reflections and scattering of the waves. The amplitude and frequency of wave propagation are mainly affected by wave propagation distance and soil compactness. The farther the vibration wave propagates, the larger the wave diffusion surface, the more dispersed the fluctuation energy, the later the onset of soil vibration, the smaller the amplitude and frequency, the simpler the soil vibration, and the larger the dynamic response within 3~6m from the source. The greater the density of the soil encountered on the way, the greater the degree of wave damage. Seismic waves have the amplification effect of converging waves at narrow interfaces and the reduction effect of scattered waves at open interfaces.

Three types of surfactants, namely anionic surfactant sodium dodecyl sulfate (SDS), cationic surfactant dodecyl trimethyl ammonium bromide (DTAB) and non-ionic surfactant Tween-80, were selected to emulsified kerosene collector. The flotation tests of low-rank coal from a coal preparation plant in Inner Mongolia were carried out and compared the flotation effect of collector before and after emulsification. The mechanism of emulsified kerosene was analyzed by laser particle size analyzer, contact Angle and Fourier infrared spectroscopy (FTIR). The results showed that when the collector dosage at 6000 g/t and kerosene is used as collector alone, the combustible recovery is 60.07% and the flotation perfection index is 30.44%. When Tween-80 emulsified kerosene is used as collector, the combustible recovery reaches the maximum, is 88.05%, and the flotation perfection index is 31.21%. The laser particle size analyzer showed that emulsification could reduce the particle size of oil droplets. The average particle size of kerosene dispersed in water was 167μm, Tween-80 emulsified kerosene was 1.19μm, SDS emulsified kerosene was 0.152μm, and DTAB emulsified kerosene was 1.52μm. Combined with the flotation results, when the average particle size of emulsified kerosene oil droplet is 1.19μm and 90% of the particle size distribution is less than 3.77μm, the combustible recovery and flotation perfection index are the highest. The results of FTIR and contact angle showed that the collector is adsorbed effectively on the surface of low-rank coal, reduces the influence of oxygen-containing functional groups on flotation, and increases the hydrophobicity of coal surface.

At present, the transmission system of heavy-duty electric-driven explosion-proof rubber-tyred vehicle in coal mine generally adopts the transmission form of low-speed motor with reducer. Because of the large difference of vehicle-to-vehicle explosion-proof rubber-tyred vehicle's operating load, heavy load and large difference of driving speed in various working conditions, it requires a wide range of motor speed regulation. In order to meet the vehicle performance, the drive system has large installed power, low efficiency and large energy loss. Aiming at the above problems, based on the closed-loop feedback control strategy of driving current, this paper develops a parallel dual-drive hybrid drive system of heavy-duty electric-driven explosion-proof rubber-tyred vehicle in coal mine, and carries out simulation test and experimental verification on the parallel dual-drive variable speed system. The results show that the comprehensive energy consumption of the parallel double-drive variable speed system can be reduced by about 11.3% compared with that of the single-drive motor system under all working conditions. Considering the influence of the parallel double-drive system on the quality of the whole vehicle, the comprehensive energy consumption of the parallel double-drive variable speed system under all working conditions can be reduced by about 10% compared with that of the single-drive motor system, and the driving range of the whole vehicle can be increased by 10% under the same other conditions. The simulation and test conclusions are basically consistent.

In order to improve the communication stability and reliability of coal mine rescue and detection robots during the rescue and detection process in confined spaces,and the passing performance of complex ground environment of underground coal mine.Develop a new type of tracked rescue and detection robot system with the function of automatically following, retracting, and releasing communication optical cables. When the rescue and detection robot moves, the automatic retracting and releasing optical cable device controls the rotation speed of the optical cable drum to match the walking speed of the robot through the detection of tension sensor tension, ensuring smooth walking and reliable communication with remote control server when the rescue and detection robot retracts and releases cables.Based on the obstacle crossing performance analysis of the rescue and detection robot Christie's suspension track walking mechanism, experimental testing results show that the rescue and detection robot can smoothly pass through 22cm steps, the cable drum communication optical cable can be retracted and released normally, the robot's four channel image data transmission is clear and continuous, the environmental detection data transmission is normal, and the overall system operation is stable.

Hydraulic reverse circulation continuous coring technique is an important technology to geological coring drilling construction, and The design of coring bit is an important factor for the successful implementation of reverse circulation. According to the characteristics of hydraulic reverse circulation continuous coring technology in underground coal mine, combined with the principle of hydraulic reverse circulation continuous coring, In this paper, through the design of hydraulic parameters of drill bit, the principle of fluid mechanics is used to allocate the water of drill bit reasonably, which not only ensures the smooth migration of core, but also ensures the smooth discharge of rock powder. The hydraulic parameters of the design are verified by flow field analysis to ensure the rationality of hydraulic parameters.Through the mechanical analysis of the interaction between the clipper and the core, the structural parameters of the clipper are optimized to ensure that the core can be successfully clipped. The cutting structure of the bit is designed, and the blade type circular arc cutter structure is used to ensure that the bit has higher cutting efficiency. Field tests were carried out with the designed drill bit. The test shows that the hydraulic reverse circulation continuous coring bit can meet the flow distribution requirements of cooling drill bit and carrying core, and the comprehensive core taking rate reaches 78%. The drilling efficiency of rock section can reach 7.5-9m/h, and that of coal section can reach 9-18m/h. It meets the requirements of high drilling efficiency, continuous coring during drilling, long pure drilling time and "real time" sampling. This study broadens the application scope of hydraulic reverse circulation continuous coring technology, and provides a drill bit scheme for coring drilling construction in underground coal mine.

In order to identify and analyze the group unsafe behaviors in coal mines and explore the internal relationship of the unsafe behavior propagation network, the coal mine accident reports in the past three years were used as the original data. Based on the grounded theory, the unsafe behaviors of various groups were extracted from the perspective of human factor analysis and group classification. The complex network theory was used to establish the unsafe behavior propagation network model. The distribution characteristics, propagation rules and internal attributes of unsafe behaviors were explored, and the key unsafe behaviors were obtained. The results show that there are common unsafe behaviors and specific unsafe behaviors in coal mine groups, and the communication network is closely related and highly correlated. Among various groups, managers and technicians are at the core of the communication network, and the key unsafe behaviors of the group mainly exist in technicians, managers and government departments.

In today's coal mine safety production system is gradually improved, the game relationship between the government, coal mines and workers has rarely been studied. In order to investigate the relationship between the government, coal mines and workers under the safety supervision system, this paper constructs a three-party evolutionary game model under the safety supervision system, uses evolutionary game theory to analyze the evolutionary game process of the game participants, studies the behavior of the three parties in the safety supervision problem and conducts stability analysis, and proposes the supervision strategy for coal mine safety production accordingly. It is found that the game between the government, coal mines and workers is a dynamic evolutionary process, and the government should reasonably determine the size of the interests of all parties involved when formulating the system, balance the interests of all parties, and fully mobilize the enthusiasm of coal mines and workers to participate in the regulation. In addition, the decision of all parties for the supervision will inevitably cause the government to supervise the department of lower earnings, should be compensated by increasing the funding. Finally, the coal mine to ensure their own interests, taking into account the cost of employee supervision required to develop incentive policies. The government sets a reasonable safety deposit in a balanced manner of coal mine revenue to increase the cost of coal mine violations. This study helps to study the relationship between the parties under the safety supervision system and provides some theoretical basis for enhancing the role of the supervision system.