In order to ensure the safe pushing of the 2201 working face of Wangcaihuopan coal mine in the overlying large-area housing mining area and the adjacent housing mining area outside the return air tunnel, analyzed the risk of coal spontaneous combustion of overlying housing mining area in 2-2 upper coal seam and the adjacent housing mining area in 2-2 coal seam during the mining process of the 2201 working face combined with the actual situation of the production site, and the main air leakage channels and areas are obtained. The results showed that the air leakage passage between the housing mining area and the working face is mainly the compound goaf formed by the roof collapse and the housing mining area, which has a certain risk of coal spontaneous combustion. For this reason, targeted coal spontaneous combustion prevention and control technologies have been put forward from the aspects of coal spontaneous combustion indicator gas monitoring, goaf grouting, nitrogen injection, and wind plugging prevention technologies, which effectively suppress and prevent coal in old goaf areas and ensures the safety of the 2201 working face.

Based on the actual situation of 7# and 8# coal seams of Datong Queshan Jingmei Co., Ltd., this paper analyzes the influencing factors such as coal seam spacing, interlayer lithology, mining height of lower coal seam, time interval and coal seam dip angle, and adopts ratio discrimination method, three zones discrimination method and surrounding rock balance method to determine that it is feasible to push goaf mining 7# and 8# coal seams. According to the analysis and judgment conclusion, from the engineering design point of view, the production capacity of 7# and 8# coal seams is proposed to be 300000 t/a; the first trial mining section is located between the western boundary of the mine field and F2 Fault; the main equipment of the mining face is preliminarily selected; and the section and support mode of the underground roadway are determined. Through the field trial production verification, the main design principles and equipment parameters proposed in this paper are scientific and reasonable. The day output of 7# and 8# coal seams is 650t, and the annual output can reach 320000t, which has achieved good benefits. Key words: coal seam groups；mining above hollow；mining design；upstream mining；comprehensive mining height

Development and update of intelligent mining technology based on coal mine.In view of the one-way coal cutting technology used in inclined coal seam mining,In the process of mining, the production technology of the shearer is different.The present situation of head and tail process asymmetry.On how to realize the normal operation of intelligent mining,This paper puts forward the intelligent mining technology of one-way coal cutting, According to the mining process at different locations of the working face,The automatic cutting process of shearer and automatic support shifting process are divided into 10 process sections.And according to the logical position relationship between the shearer and the support,Define the trigger position of each stage of the hydraulic support control program,Realize the normal operation of one-way intelligent mining.According to the cutting speed and position of the shearer, the intelligent linkage shift mode is put forward.Improve the utilization rate of intelligent mining technology in the field.Through the field engineering application of 220704 working face in Zaoquan Coal Mine of National Energy Group,The intelligent mining technology of one-way coal cutting has been achieved in the normal and efficient mining in the field production process.In 295 meters of the working face to achieve intelligent mining of the daily cutting of coal reached 13.The experience is provided for the intelligent mining one-way coal cutting process.

Abstract: This paper describes the "one" layout of the skip in the super large mine. By analyzing the geological conditions of the surrounding rock of the shaft, the double-layer cast-in-place reinforced concrete (or steel fiber concrete) HDPE plastic sandwich composite shaft wall is designed, and the single-layer steel fiber + steel reinforced concrete shaft wall structure is adopted in the lower non freezing section; According to the load of two pairs of 50t skip and the large force (including vertical and horizontal direction) of skip up and down operation on the tank channel and the tank channel beam, and considering the cold bending process and material consumption of the tank channel steel, the cold-formed rectangular hollow steel tank channel beam, 32c I-steel support beam and angle steel are used to make the tank channel beam support to ensure the safe operation of the lifting vessel. Up to now, the hoisting system is in good working condition and running normally, achieving the goal of 15 million T / a design production capacity of the mine. The successful research and development of the project has systematically solved the core problem of restricting the construction of super large deep main shaft engineering project, and also provided research basis for China's non coal mine shaft hoisting and national defense underground industry.

Aiming at the problems of low efficiency of data utilization, poor correlation degree and insufficient value mining faced by the construction of intelligent coal mine at present, a method of constructing information entity as the center of information transmission to establish virtual-real mapping system is put forward. This paper analyzes the connotation of the information entity, points out that the information entity can be physical, functional or event information entity, and puts forward a method to analyze and mine the information entity according to the explicit and implicit requirements. This paper analyzes the difference between constructing virtual-real mapping system based on information entity and traditional method, and puts forward a method of establishing virtual-real mapping system based on time dimension "slice" of information entity. Taking fully mechanized mining conveying equipment as an example, seven corresponding information entities are constructed, a virtual and real mapping monitoring system based on the information entity of fully mechanized mining conveying equipment is designed, and a simulation and experiment platform is set up in the laboratory. The test results show that the system runs reliably and realizes the efficient acquisition and utilization of the working condition data of fully mechanized mining and conveying equipment. The research results of this paper provide technical support for the realization of intelligent mining efficient information acquisition and utilization.

After the introduction of mining rights transfer revenue, the policy differences of provinces and regions are very large. This paper takes Shanxi province as an example, discussion on the difference of collection and payment before and after reform. This paper discusses the impact of mining rights system reform on project decision-making, combining with the comparative analysis of project financial indicators before and after the reform of Shaanxi resource acquisition project.

Aiming at the problem roof cutting and pressure releasing; along the empty lane in Halagou Coal Mine, the research adopts numerical simulation and physical experiment methods to carry out a systematic study. The results show that the method of cutting the roof and leaving the roadway along the goaf can cut off the stress transmission path between the roadway and the overlying rock on the roof of the goaf, so that a certain range of the roof has a stress relief area, and effectively control the development of the roadway deformation. U-shaped steel support can be divided into three stages: elastic deformation, microslip and large slip, and the ultimate bearing capacity of the U-shaped steel increases with the increase of the torque. When the torque is the same, the ultimate bearing capacity of U29-shaped steel is higher than U25-shaped steel, and the supporting effect is better. Finally, the supporting method of gob-side entry retaining is given from the perspectives of advanced area, lagging area and stable area of roadway, which can effectively solve the Supporting problem of roof cutting and pressure releasing along the empty lane.

Taking gob-side entry driving of 3-1101 working face in Hongqinghe coal mine as the engineering background, the internal and external stress field theory, limit equilibrium zone theory, numerical simulation and engineering practice are comprehensively applied to determine that the reasonable width of narrow coal pillar in gob-side entry driving with deep large mining height is 6 m. The combined control technology of bolt-cable-shotcreting is put forward. The results show that: (1) The width of the internal stress field is 12.5 m, the width of coal pillar broken area is 2.1 m under the mining influence in the upper section, and the reasonable width of the narrow coal pillar is 4.7 ~ 7.3 m. (2) When the coal pillar size is 6～10 m, there is a certain stress concentration in the pillar and the solid coal side. The stress of the coal pillar is enhanced. The elastic area appears in the surrounding rock above the coal pillar and the roadway, which is conducive to the bolt (cable) to play the role of anchoring. (3) The 6 m width narrow coal pillar and combined control technology of bolt-cable-shotcreting can effectively control the large deformation of surrounding rock of gob-side entry driving. The integrity of the coal body in the roadway roof and wall more than 2.6 m is good. After 35 days, the convergence deformation of the roadway tends to be stable. The maximum deformation of the roof on the coal pillar side, the roof on the solid coal side, the coal pillar wall and the solid coal wall are 63 mm, 57 mm, 46 mm and 34 mm respectively.

Aiming at the problems of large deformation and difficult support of surrounding rock of deep chamber group tunnel in a coal mine, the physical and mechanical parameters of surrounding rock of chamber group were measured through field sampling. According to the loose circle theory, the loose circle size was calculated as 2.63 ~ 3.11 m, which indicates that the length of anchor cable could not meet the support demand. By using FLAC3D software, the stress distribution and deformation characteristics of surrounding rock after excavation were further studied, and the deformation and failure mechanism of surrounding rock was analyzed. The results show that complex in-situ stress, insufficient support strength and unsupported floor are the main causes of deformation and failure of surrounding rock. Based on the theoretical analysis and numerical simulation, the combined control technology of bolt mesh cable grouting reinforcement is applied to reinforce the surrounding rock of roadway roof and floor. The numerical simulation results show that the deformation of roadway surrounding rock is effectively controlled, and the maximum deformation of roof is 30 mm. The field monitoring results show that the maximum deformation of roof is 30 mm within 180 days, which achieves the ideal reinforcement effect.

In order to ensure the safe and efficient connection of the 8.8m super large mining height fully mechanized mining face, this paper compares and analyzes the main risks and technical problems in roof management, ground pressure control and net hanging of end- mining and penetration stage of the 8.8m super large mining height fully mechanized mining face, and puts forward the following suggestions: using booster pump equipment, hydraulic fracturing technology, post-pressure mining and improving the support strength of retracement channel. Through the technical application, the initial support force of the hydraulic support of the working face is increased to 30MPa, the dynamic load factor of the roof at both end heads is significantly reduced, and the end- mining and penetration of working face lags behind a small periodic pressure 4m. After the penetration, the surrounding rock of the mining field and the main retracement channel effectively prevents the occurrence of roof accidents in the 8.8m super large mining height fully mechanized mining face, and realizes the safe production of the working face, These control technologies provide a reference for the fully mechanized end mining penetration of shallow depth and extra thick coal seams.

In view of the problems of large coal seam undulation, high risk of coal and gas outburst and fault development in the K1 outburst single thin coal seam of L Coal Mine, from the analysis of complete area energy dissipation and local pressure relief to increase permeability, they are proposed that the working face drilling hole along the layer, coal road floor drilling hole of penetration the layer, floor grid drilling hole of penetration the layer and structural belt deep hole blasting, hydraulic flushing in hole, advanced discharge drilling hole integrated anti-outburst technology system. The on-site drainage results of the 3124S intelligent fully mechanized mining face show that after the use of integrated anti-outburst technology, the gas drainage concentration is increased by 1.32 times, the drainage volume is increased by 1.27 times, the gas drainage efficiency is more than 46%, laying the foundation for the safe and rapid advancement of intelligent fully mechanized mining face in outburst thin coal seams.

In order to improve the sealing quality of downward drainage hole and ensure the effect of regional gas control, there are many slag deposits at the bottom of the hole and the drainage pipe can not go down to the design position, which lead to poor sealing effect. At the same time, the slag deposits are easy to block the screen hole of the drainage pipe and hinder the migration of gas, A gas lift reverse circulation slag cleaning device based on compressed air was developed and industrial test was carried out. The research results show that: the gas lift reverse circulation slag cleaning device with compressed air as power and clean water as flushing fluid can smoothly discharge the accumulated slag out of the down hole, and the net hole depth of the test hole accounts for 13-41.6% of the actual hole depth, with an average of 21.4%, which improves the effective depth of the down hole and ensures the sealing quality, The effect of gas drainage is obviously improved.

Aiming at the problems of multiple dust producing points, high dust concentration and poor working environment in coal mining face, the dust diffusion along the coal mining face and the dust concentration distribution in the shearer area are measured and analyzed by using the mass method. On the basis of the research of gas-water atomization technology, the shearer's high efficiency gas-water atomization external spray is taken as the main dustfall measure, and the transfer crusher's dust prevention and the whole section of roadway's gas-water atomization are taken as the auxiliary dustfall measure. The technology of multi-dust source joint control and dustfall in coal mining face based on gas-water atomization is proposed, and the multi-dust source joint control and dust reduction device is developed and applied in coal mining face 42222 in Chaijiagou well. The results show that the dust concentration increases first and then decreases along the coal mining face. The shearer area is the main dust source point, and the dust concentration appears superposition effect near the coal dust source point. The total dust concentration of downwind coal cutting of shearer is greater than that of downwind coal cutting, and the maximum total dust concentration appears on downwind side of shearer. The average dust removal rate is more than 80% after using multi-dust source joint control technology, which can effectively improve the working environment of coal mining face.

Aiming at the characteristics of Zhaozhuang Coal Mine's surface CBM vertical fracturing wells and gas extraction is not satisfactory, taking Zhaozhuang Coal Mine No. 3 main mining seam as the research object, by carrying out field sampling test, extraction mode analysis, numerical simulation, field test and other research work, put forward a CBM drainage mode of free section coupled with staged hydraulic fractured horizontal well. Research indicates: the No. 3 coal seam is composed of a stable hard coal structure on the upper part and a relatively stable soft coal structure on the lower part, with obvious stratification, the horizontal well deployed in the upper hard coal seam can effectively increase the drilling rate, and the free horizontal section formed can effectively reduce the pollution and damage to the coal seam caused by cementing operations, at the same time, hydraulic sand blasting is used for perforation and oil casing annulus reinforcement，sand fracturing establishes a network of fractures and forms formation gas channels. The numerical simulation results of MFrac Suite fracturing revealed that the hydraulic sandblasting and perforating fracturing process with large displacement and medium sand ratio can tear the coal seam vertically， from the upper hard coal into the lower soft coal, multiple sets of complex and irregular vertical fractures are formed, and at the same time, a certain length of fractures are formed in the horizontal direction, which can achieve a good fracturing effect. Field test engineering results have verified that this model has a good gas production effect, the maximum daily gas production volume exceeds 5100 m3. As of January 31, 2020, the cumulative gas production has exceeded 3 million m3, and the extraction effect is remarkable.

In order to study the development characteristics of the overlying strata fracture under coal seam group mining, similar material simulation experiments and theoretical analysis methods were used to carry out similar simulation experiments for mining at 31114 working face of Lijiahao Coal Mine. The evolution law of overlying strata fracture under the single coal mining and superimposed mining is analyzed, and the mechanism of superimposed mining on the development of overlying strata fracture is revealed. The results show that the overlying strata collapse, strata behavior and fracture development in the upper coal seam are the same as those in single coal seam mining. After the mining of the lower coal seam, the balance of the overlying strata collapse structure of the upper coal seam is destroyed under the influence of superimposed mining. and a large number of fissures developments. After the roof of the lower coal seam is broken, the collapsed structure of the overlying strata of upper coal seam goaf is unbalanced, and some of the rock layers rotate to form a vertical fissure area. In the initial stage of mining of the lower coal seam, the periodic weighting step distance is alternated with long and short. After the working face of the lower coal seam passes through the goaf of the upper coal seam, the main key layer is broken, the overlying strata straddles as a whole, and the mining pressure of the working face is obvious.

According to the surrounding rock control technical difficulties in controlling the deformation under the influence during twice mining face in of dual lane working face, the 1105N working face of No.1 coal seam of Danhou mine is taken as the engineering background in this paper, by theoretical calculation and FLAC3D calculation, the deformation characteristics of the surrounding rock in the inset passage of 1105N working face with different width coal pillars are obtained, and the parameters of bolt (cable) support in 1105N lane are optimized. The findings are as follows: the width of narrow coal pillar is 6~8m if small coal pillar is left, the width of the coal wide pillar is 21.96m in the section of No.1 Coal Seam. Through numerical simulation，it is confirmed that the reasonable width of the coal pillar is 22m in the section of No.1 coal seam, in addition, the support method of the air inlet raodway in 1105N working face is optimized and the support effect is verified. The results of this study provided a basis for retention of coal pillar in subsequent mining section and had certain reference value for coal mine under similar engineering geological conditions.

Based on gu north mining area of thin bedrock face is easy to appear the characteristics of the water bursting pressure to achieve safe and efficient mining of working face, gu north mine 1512 (3) working face as engineering background, the similar simulation experiment, numerical simulation and in-situ observation method, to study the different formations of the strata movement rule of fully mechanized working face, the influence of with thin bedrock wind oxidation grouting reinforcement technique is proposed and successfully conducted industrial test.The results show that for the single bearing layer structure advancing with the working face, the water inrush and pressure of the working face are easy to occur because the load of the support is too large to bear the load transferred by the upper strata.The double bearing layer structure of the overlying strata can block the stress transfer of the overlying strata and reduce the risk of crushing the working face.Based on the results of the study, the north mine 1512 (3) working face wind oxidized zone adopted the grouting reinforcement method, build an effective high above the stope bearing layer, reduced the load on the hydraulic support, reduces the intensity of mine pressure appear, to ensure the safety mining of working face, the results for the similar working conditions under the condition of water inrush prevention and control of crushing problem provides a certain reference value.

Due to the weakness of the coal seam and the immediate roof under the “double-soft” coal seam mining conditions, there are problems such as abnormal rock pressure and the easy instability of the surrounding rock. It is difficult to manage the roof of the working face. Mastering the characteristics of rock pressure and the laws of overlying rock activity is the key to solving the problem of surrounding rock control in "double-soft" coal seams. Taking the Changping Coal Industry 3# coal seam as the research background. Based on the analysis of the monitoring data of poppet pressure and roadway surrounding rock stress, combined with the microseismic monitoring technology, grasp the roof breaking mechanism and time-space relationship, and study the response mechanism of rock pressure law and roof activity characteristics. Reasonable interpretation of the rock pressure law from the perspective of microseismic energy. Draw the following conclusion: Weak rock pressure, segmented local compression, high pressure in the middle and low at both ends; The two roadways have a large range of influence in advance area, the farthest impact distance exceeds 200m; The leading failure of the working face roof and the frequent occurrence of high-energy microseismic events in the two lanes are the main reasons for the low strength of the working face, the large influence range of the leading stress of the two roadway, and the obvious difference in the tendency of the working face.

In order to clarify the mechanical bearing mechanism after the bolt support body is coupled with the surrounding rock of the roadway after installation of the 150802 working face of Liuzhuang Coal Mine, and at the same time, the theoretical analysis is adopted to solve the problems of serious deformation of the roadway surrounding rock in Liuzhuang Coal Mine and the difficulty of bolt and cable support. Formula derivation, experimental testing, numerical simulation and field test, etc., respectively established the mechanical constitutive model of the surrounding rock partition after the excavation of the roadway and the mechanical constitutive model of the coupled mechanical constitutive model of the bolts installed in the different surrounding rock partitions, and deduced Its mechanics expression is simulated by FLAC-3D numerical software after the bolts are installed in different surrounding rock partitions, and engineering practice is carried out. The research results show that the mechanical state of bolts installed in the surrounding rock in the plastic zone and the surrounding rock in the elastic zone is quite different. The deformation trend of the bolt in the surrounding rock in the plastic zone is obviously greater than that in the surrounding rock in the elastic zone. The expression differences are consistent.

Aiming at the complex stress problems such as nonlinear and strong coupling when the drum of the permanent magnet outer rotor hoist is running, the dynamic load deformation and optimization of the drum of the mine permanent magnet outer rotor hoist are studied. Firstly, the electric control-mechanical joint simulation model of permanent magnet outer rotor hoist was built by SimulationX software, and the dynamic tension and electromagnetic torque of steel wire rope under heavy load lifting condition were accurately obtained. Then, the stress and deformation law of outer rotor drum were obtained by finite element numerical simulation. Finally, the steel wire rope winding drum was separated from the rotor yoke by isolation ring or reinforcing rib, and its structure was optimized. The research shows that the maximum equivalent stress and radial deformation of the outer rotor drum increase nonlinearly under the heavy load lifting condition, and the maximum stress and deformation are basically stable in the fixed area during the whole operation stage. The optimization method of separation treatment is adopted to effectively reduce the air gap deformation between stator and rotor. The research results have certain reference value for the structural design and optimization of drum of permanent magnet outer rotor hoist.

Compared with cascaded multilevel rectifier, hybrid cascade bridge rectifier does not need power frequency phase-shifting transformer, which has been widely concerned in recent years. This paper analyzes the circuit topology, working principle and control strategy of hybrid cascade bridge rectifier circuit and cascade multilevel rectifier circuit, and compares the frequency converter based on the above two circuit topologies from the aspects of volume and cost, and analyzes the application prospect of mine frequency converter based on Hybrid Cascade bridge rectifier. The analysis show that the hybrid cascade bridge rectifier circuit can not only save cost, reduce switching loss and harmonic pollution, but also reduce the volume and weight of the whole device, which is conducive to the installation and use of frequency converter in the narrow space of coal mine.

In order to analyze the influence of the development fractures to air leakage when mining in the goaf of shallow coal seams, this paper takes the 5-2 coal face of Anshan Coal Mine as the research background, based on the knowledge of the overburden fractures’ characteristics of mining and the air flow, Though field measurement and theoretical analysis, this paper studied the air conduction’ characteristics of mining. The research shows that after the mining of the 5-2 coal face, the surface fractures are distributed at approximately equal intervals and parallel, and the periodic weighting step is 14m on average; under sub atmospheric pressure ventilation , the amount of air leakage in the goaf near the return air way is large, and when the fracture opening is less than 0.4m, the amount of air leakage does not change much; along the direction of the mining face, the fractures’ development area of the mining in the goaf is over 210m, and the mining face should be produced during the shortest spontaneous combustion period of the coal seam, This measures is to pre-vent spontaneous combustion of coal left in the goaf.

In order to explore the evolution law of the physicochemical properties of water-immersed air-dried coal and its influence on the initial spontaneous combustion characteristics of coal, based on the combination of electron spin resonance spectrometer and gas atmospheric pressure adsorption instrument, the two types of free radical energy storage and coal oxygen adsorption The mechanism of the influence of water immersion time on the initial spontaneous combustion characteristics of water-immersed air-dried coal was studied at various levels, and the effect of water immersion on the competitive adsorption characteristics of coal and multi-element gas was studied for the first time. based on the electron spin resonance spectrometer and the gas atmospheric pressure adsorption instrument, the adsorption of free radicals and coal oxygen was studied at two levels The influence mechanism of immersion time on the initial spontaneous combustion characteristics of air-dried coal. Studies have shown that the types of free radicals in coal continue to decrease with the increase in water immersion time, while the concentration of free radicals Ng increases with the increase in water immersion time. At the same time, on the one hand, due to the dissolution and dissipation of some components of the coal body and water absorption by the matrix Expansion makes the coal porosity and the adsorption of dry air and other gases increase with the increase of the water immersion time. On the other hand, the transformation of the coal pore structure due to the water immersion promotes the O2 adsorption capacity of the coal. It should be greater than N2, so that the amount of oxygen adsorbed by the coal and the oxygen content in the adsorbed gas will increase with the increase of the water immersion time;. Therefore, from the perspective of energy storage and coal oxygen adsorption, the initial spontaneous combustion risk of coal continues to increase with the increase of water immersion time. It is instructed that we should also consider the effect of water immersion on the promotion of coal spontaneous combustion in the process of preventing and controlling spontaneous combustion of water-immersed air-dried coal effect.

In order to evaluate the feasibility of underground gasification of long flame coal in Ningxia, the pyrolysis experiment of long flame coal in Wangwa mining area of Ningxia was carried out, and the parameters of underground gasification of long flame coal were calculated by using the material and energy balance modle of UCG. The results show that the maximum weight loss temperature of Ningxia long flame coal pyrolysis in N2 atmosphere is 108 ℃, the weight loss rate of end reaction is 33.13%, and the activation energy is 59.77kJ/mol; In CO2 atmosphere, the maximum weight loss temperature is 950 ℃, the weight loss rate is 66.83%, and the activation energy is 31.33kJ/mol; With the increase of oxygen concentration, the content of effective components (H2 + CO + CH4), calorific value and gasification efficiency of gas increase, and the gas yield per ton of coal decreases; When pure oxygen-water gasification is used, the effective component of the gas reaches 68.12%, the high calorific value of the gas reaches 9.93MJ/Nm3, and the cold gas efficiency reaches 73.05%.

As a clean in-situ coal conversion technology, underground coal gasification has a broad development prospect. Typical coal underground gasification projects at home and abroad are summarized, and it is found that coal underground gasification technology is feasible. However, the commercial development still faces technical challenges such as gasifier tightness, gasification operation control and hydrogeological conditions issues. Groundwater and environment monitoring is one of the important ways to evaluate the effect of underground coal gasification. In some areas with unfavorable hydrogeological conditions, a large amount of water bursting into gasification chamber and/or formation water pollution may occur, which restricts the long-term safe and stable operation of underground coal gasification. Scientific site selection is an important prerequisite to realize the commercial development of underground coal gasification. It should not only be conducive to the stable and efficient production of crude gas, but also reduce the risk of groundwater pollution and/or avoid pollution at the sources. Interaction factors hydrogeological conditions and underground coal gasification mainly include groundwater occurrence characteristics, water inflow, distance away from the aquifer, effectiveness of confining layer, degree of water recharge & degree of difficulty in prevention, gasification residue dissolved in the groundwater & its infiltration and migration, and so on. In the future, it will need to further strengthen research about related parameters and the threshold of specific evaluation index, in order to guide the exploration and development of underground coal gasification.

The test was carried out with industrial production line equipment, and the single-stage wet pulping process was adopted to prepare long-distance pipeline transportation coal water slurry with mass concentration of about 50%. By adjusting the main process parameters such as feed particle size, feed amount and rod feeding amount, the variation law of coal grinding efficiency with rod loading of MBS4360 overflow rod mill was found It is concluded that the loading of rod mill should not be less than 70.7% in the process of industrial production. This test procedure and analysis method can be used for reference for other types of rod mills and ball mills, and can be used for reference in coal processing related industries.

This paper analyzes the limitations of rail and walking robot in the process of inspection of coal mine belt conveyor, and puts forward a new way of inspection using flying robot. Aiming at the situation of GPS refusal environment and poor illumination condition in underground coal mine, the method of laser slam combined with millimeter wave radar aided height determination is studied to realize autonomous navigation flight of quadrotor robot in underground tunnel. This paper analyzes the inspection requirements of the robot according to the established line and remote control flight, and uses the 5g network based on SA architecture as the transmission channel to meet the requirements of high-definition inspection video upload with large bandwidth and low delay reverse remote control flight of the quadrotor inspection robot. After field test, the quadrotor inspection robot designed in this paper can realize autonomous navigation flight and remote control flight in the underground belt conveyor tunnel.

As a new type of torque transmission device, permanent magnet coupling (PMC) is increasingly widely used, which is new choice for torque transmission equipment of mine. PMC have soft-start and overload protection functions for constant torque loads. They are suitable for scraper conveyors and belt conveyors. However, there is currently a lack of in-depth research of their soft-start and overload protection characteristics. In order to further research its soft start and overload protection characteristics,, design and manufacture a prototype of a cylindrical permanent magnet coupling (CPMC) with a rated power of 6 kW for experimental testing, set up a test bench, , the experimental research shows that compared with coupling start, decoupling start reduces the motor start time by 32% and the peak current by 34%, which has better soft start performance; The motor power supply or coupling should be cut off within 16 s to protect the motor and the coupling.

Coal resource is a mineral resource with comparative advantages in China, and it occupies a dominant position in the structure of my country's primary energy consumption. The coal resource-rich areas have made important contributions to guaranteeing national energy security and sustained and stable economic and social development. However, due to the "excessive dependence" on resources, the "heaviness" of the industrial structure, the overload of ecological load, and the extensive development mode of such regions are still outstanding.Taking Inner Mongolia as an example, based on the structure of the transformational development system of coal resource enrichment areas and its internal interactions, a system dynamics model was constructed, and simulation plans for the development of coal resource enrichment areas under different scenarios were set up to reveal the characteristics of regional development power. , Generation mechanism and visual presentation. The results show that under the coordinated development plan, the economic development of coal resource-rich areas has reached a medium-to-high speed level, the problem of widening the gap in regional economic development tends to narrow, regional infrastructure and basic public services are improved, ecological pressure is reduced, and the ecological environment is more improved. optimization. The article puts forward countermeasures and suggestions to promote the transformation and development of coal resource-rich areas from two aspects: "filling shortcomings" and "promoting coordination".

In the background of the high-quality development of China's economy, the high-quality development of the coal industry has attracted widespread attention from scholars. Through combing the relevant literature on the high-quality development of the coal industry in recent years, it can be summarized into three themes: the connotation of the high-quality development of the coal industry, the evaluation system of the high-quality development of the coal industry, and the path of the high-quality development of the coal industry. Reference to the existing research results, combined with the author's own thinking, the author put forward the concept of high-quality development of China's coal industry: safety concept, production concept, management concept, employee concept, environmental protection concept and sharing concept.

Based on Chinese coal listed companies from 2012-2018, we empirically tested the impact and mechanism of corporate social responsibility of coal enterprises on total factor productivity. The results show that coal enterprises' can improve total factor productivity by fulfill their social responsibilities, managerial myopia and corporate reputation play an intermediary role in this process, the findings of the study remain unchanged by PSM test. The study has implications for coal enterprises to practice social responsibility and improve total factor productivity to achieve transformation and upgrading.