Aiming at the high quality development problem of large coal mining area in our country, the paper systematically expounds the core concepts of "six coordination" of high quality development path of Xinjie Tegemiao mining area, studies the implementation path of intelligent, efficient, safe, green and zero-carbon mining area construction, analyzes the key problems of efficient and coordinated mining of gas, joint arrangement of multiple Wells, and sharing of supporting projects. It has determined the development goal of building a clean, integrated, refined, intelligent and internationalized first-class model mining area, which is advanced, forward-looking, strategic, coordinated and intensive, and has certain demonstration significance for the high-quality development of similar large integrated mining areas in China.

The quantitative rock burst risk assessment model, a theory-based and data-driven fusion of rock burst risk assessment method, has broad prospects in the field of rock hazardous burst, but there is still relatively little research on the application of this technique to assess impact hazards. In this paper, the quantitative rock burst risk assessment model is combined with real-time monitoring data to perform a real-time quantitative risk assessment of the hazards during the retrieval process of the 7302 working face in the Heze Zhaolou coal mine, and the area of strong rock burst risk assessment (risk assessment value > 0.75) is analyzed and verified. It was found that the strong rock burst risk area was proportional to the electromagnetic radiation value and had good consistency, which verified the feasibility of the quantitative rock burst risk assessment model. On this basis, the rock burst risk prediction for the subsequent mining process was carried out using the current data. By comparing and analyzing the changes and evolution of the risk zone, a reduction plan with a relatively low Rock burst risk was identified.

Considering the problems existing in the quantitative loading station, such as low degree of automation and intelligence, high manual operation intensity, imprecise loading effect and so on, a precise loading system for fast quantitative loading station is designed in this paper. according to the composition and working principle of the fast quantitative loading station, the system studies the control technology including car number acquisition, quantitative warehouse valve control technology and coal chute control technology. Through the information collection and processing of different equipment and the control of different equipment, the fast quantitative loading of the station and accurate loading is completed by the programmable controller PLC. In view of the current quantitative loading station loading mode is backward, there is no residual coal detection system, loading is not accurate and so on. This paper designs a set of detection method of residual coal carbon in the car, mainly through two-bit lidar scanning the inner surface of the car to be loaded and generating point cloud data, through the point cloud data processing to get the three-dimensional image of the coal in the car, filtering the image to further get the quality of the residual coal in the car to achieve non-contact weighing. Finally, the key technology of fast quantitative loading station is verified in Baiyinhua Mengdong open-pit coal mine in Inner Mongolia. The research content of this paper provides a basis for the research and development of train fast quantitative loading system in open-pit mine.

Abstract: Under the background of intelligent upgrading of coal mine transportation system, this paper selects a single transportation scene from coal mine to power plant, puts forward three different transportation system schemes, and points out that the application scenarios of different transportation systems.Combined with the transportation scenes from specific coal mines to power plants, this paper makes a comprehensive comparative analysis of different transportation schemes from qualitative and quantitative perspectives, and points out the necessity of intelligent upgrading of transportation systems. This paper also gives the optimization and selection method of transportation system schemes in specific scenes, so as to provide enterprises with reasonable selection of transportation schemes with better technology and economy.

Dense medium separation process occupies a dominant position in the development of coal preparation industry, but the dense medium separation process often has strong nonlinear characteristics due to the complex process and the large disturbance. In this paper, a multi-model switching adaptive control method is proposed for the density loop of dense medium separation. First, random vector function link network (RVFLN) is employed to estimate the unmodeled dynamics of the system, and linear and nonlinear adaptive controllers are designed. Based on them, the switching mechanism is designed to make the controllers switch according to the raw coal quality, and further improves the control performance and accuracy, thereby improving the economic efficiency of coal preparation plants. Finally, simulation experiments with actual data have been carried out on the density loop of dense medium separation, which shows the effectiveness of the proposed method.

In order to solve the problem of deformation and failure of surrounding rock caused by long cantilever extrusion roadway, which is formed by thick and hard roof, this paper takes the typical working face of Caojiatan Coal Mine as the engineering background. The TRIZ theory was used for systematic analysis, and the cause of the deformation of the surrounding rock of the roadway was determined by the causal relationship method. The principle of spatial separation was used to separate the roof of the goaf from the roof of the roadway, and the roof of the goaf was softened by the pre-action method to achieve the purpose of timely caving and filling of the thick and hard roof. Based on TRIZ theory, a combined blasting technology of ' directional cumulative blasting + non-directional reinforced blasting ' was proposed. The key parameters of combined blasting were determined by theoretical analysis and verified by numerical simulation. On this basis, the combined blasting scheme was designed. Finally, field engineering tests were carried out. The field application results show that the problem of deformation and failure of roadway surrounding rock is effectively solved by using combined blasting technology.

Abstract: Based on the engineering background of 11101 transport passage in Qipanjing Coal Mine (east area), the law of roadway retaining pressure in cross roadway of medium thick coal seam is studied. In this paper, the stress distribution characteristics in the process of roadway retention are obtained by numerical simulation, and the surrounding rock support scheme and mine pressure monitoring scheme are put forward. The results show that: with the working face mining, the peak value difference of stress concentration on both sides of 11101 drainage lane at the intersection of roadway is increasing, and finally the peak value of stress concentration on the left side of roadway is greater than that on the right side. The roof at the roadway intersection is in a "weak stable" state relative to both sides of the roadway intersection, which is easily affected by the mining pressure of the working face. Through the field verification, the reinforcement support measures at the roadway intersection are reasonable and meet the expected requirements.

Song Xinzhuang Coal Mine 110303 working face return airway is affected by 110301 working face mining, the roadway shows large deformation characteristics and cannot meet the normal production needs. Therefore, during the mining of the working face of the wing 110302 in the mining area, the roof of the transportation roadway is constructed intensively drilling and cutting top relief technology, so as to optimize the post-mining lateral stress distribution of the 110304 return airway. Combined with the geological conditions of the working face, through theoretical analysis and Flac3D numerical simulation, key technical parameters such as roof cut-ting height, angle and hole spacing were determined, and the stress evolution law of the surrounding rock of the roadway before and after roof cutting was studied. The amount of displacement in the roadway was signif-icantly reduced. Industrial tests have shown that after the top cut and pressure relief, the development of fis-sures in the roof and surrounding rocks of 110304 return airway was reduced, the relative displacement of the two helpers was 249 mm and the relative displacement of the top and bottom plates was 237 mm. This tech-nology can provide some technical reference for subsequent mining in Song Xinzhuang coal mine.

The borehole inclination correction of geological exploration needs to master the reasonable borehole inclination correction and calculation method, and obtain the offset distance after the borehole is projected on the exploration line section, so as to draw the exploration line section. According to the angle between the stratum strike and the exploration line, this paper divides the hole inclination correction projection method into three cases. Based on the study of the relationship between the stratum and the three-dimensional space and trigonometric function of the borehole, the calculation formulas for different projection methods are unified respectively. Without judging the exploration line and hole inclination orientation, the deviation measurement data is directly used to bring into the formula calculation. Through the calculation and verification of the hole inclination data of previous exploration boreholes through Excel, it shows that the calculation formula is correct. When the occurrence of the local layer and the orientation of the exploration line are certain, the larger the top angle of the hole section, the deeper the borehole, and the greater the difference of the cumulative offset distance of the section caused by different projection methods.

Aiming at the coal pillar type impact instability caused by high ground stress caused by thick roof rock, large reserved width of coal pillar and buried depth of 500 ~ 700m in Ordos mining area, a mechanical model for calculating the internal stress of coal pillar is established, and the coal pillars with different stress performance characteristics are classified and discussed. The internal stress of components is calculated based on the superposition principle of elastic mechanics combined with rock mechanics and material mechanics, The calculation formula of the maximum and minimum intermediate principal stress is derived after the conversion of the three-dimensional stress at any position in the coal pillar. Secondly, taking the 3102 working face of menkeqing coal mine as the background, the theoretical calculation and FLAC3D numerical simulation experiment are carried out, and the accuracy of the deduced calculation formula of coal pillar internal stress is verified based on the field measured data. Finally, the critical starting conditions of coal pillar type rockburst obtained according to the internal stress calculation formula can be used as an effective measure and means to guide the on-site prevention and control of the impact phenomenon caused by the high internal stress of coal pillar.

Aiming at the problems such as the difficulty of the roof collapse during the initial mining of the first mining working surface under the condition of hard roof plate, the 2102 working surface of Balassu Coal Mine is used as the research background, Using theoretical analysis and field experiments, the mechanical structure model of the first collapse of the working surface was established. The hydraulic fracturing comprehensive weakening treatment technology of directional long drill + short drill is proposed. The weakening effect of the roof after fracturing is comprehensively evaluated, and the characteristics of ore pressure during the initial mining period after fracturing of the first mining surface are analyzed and mastered. Studies have shown that: When hydraulic fracturing is not performed, the ceiling area of the roof plate is large, and the mechanical model calculates the initial collapse step distance of 77m. It is concluded that the working surface is reasonably hydraulic fracturing range vertical to 12.26m~23.43m, and the horizontal direction is within 30.8m; The maximum pressure of directional hydraulic fracturing reaches more than 26MPa, and the short drill fracturing reaches more than 52MPa, both of which show significant pressure drop, and the maximum drop reaches 26MPa; After fracturing, the peep effect of the hole is good, and the water outlet phenomenon of the adjacent hole is obvious. The ore pressure of the roof of the working surface is mainly manifested as the characteristics of frequent small pressure, and the initial pressure strength increases by 14.14% compared with the promotion of 30m. The synthesis shows that the effect of hydraulic fracturing is remarkable. Through the comprehensive three-dimensional advanced treatment technology system of "directional long drilling + conventional short drilling", the safe recovery during the initial mining of the 2102 working surface is realized, which provides a reference treatment method for the treatment of strong mineral pressure disasters in the initial mining stage of the working surface under similar conditions.

Under the "U" type ventilation condition of the first mining face of the group of close high gassy coal seams, a large number of gas from the adjacent layers poured into the upper corner through the cracks generated by the pressure relief of the coal and rock mass and entered the return air flow, resulting in the gas over limit. Taking the 03X04 mining face of Dongyu coal mine as the research object, the pressure relief gas migration law in the goaf under the "U" type ventilation condition of the mining face was analyzed, so as to determine the belt The "one side and four lanes" combined gas control technical scheme of track trough + high and bottom drainage roadway. The field application results show that the gas extraction rate of the working face has reached 81%, the gas content of this coal seam has decreased by 33%, the net amount of gas extraction from the intercepting boreholes of the side and bottom drainage roadway completely within the pressure relief range has reached 0.02m3/min ~ 0.03m3/min per hole, the maximum gas extraction concentration has reached 90%, and the net amount of gas extraction has increased by more than 2 times, greatly reducing the influx of gas into the working face and the upper corner of the lower adjacent layer, The gas concentration of the return air flow in the track trough and the side bottom drainage roadway of the mining face is stable at 0.2%～0.4%, and the gas concentration in the upper corner is 0.3%～0.4%, which effectively solves the problem that the gas in the upper corner and the return air flow exceeds the limit under the "U" ventilation condition of the mining face, and ensures the safe and efficient production of the mine.

Aiming at the problem of drilling hole layout for gas extraction under the influence of mining in adjacent layer in high gas mine,introduced the theory of pressure relief effect and gas overflow during mining in outburst coal seam protective seam,the gas overflow effect of mining pressure relief in adjacent layer and the gas drainage effect of mining pressure relief in adjacent layer were demonstrated in fully mechanized caving face I011501,and the optimum layout scheme of pre-pumped boreholes was put forward. Through engineering practice and effect evaluation,the results showed that:Pre-extraction effect of I011501 fully mechanized caving face before mining still meets the requirements of relevant regulations under the condition of enlarging the distance between drilling holes and reducing the quantity of drilling construction works,6.9m gas drainage radius can meet the needs of gas drainage of fully mechanized caving face in M15.

Aiming at the unsynchronized problem of the column lifting process of the shield hydraulic support, based on the analysis of the column lifting conditions, the column hydraulic control one-way valve column lifting model was built, the expression of the valve core opening amount of the column hydraulic control one-way valve was established based on the force balance of the valve core, the theoretical conditions of the column unsynchronized were given, and the AMESim simulation model of the column lifting system was established. The influence of column load and damping hole diameter of hydraulic control check valve on column synchronization is analyzed. The analysis results show that the root cause of the two columns' asynchrony is that the loads of the two columns are different, and the greater the load difference, the greater the difference in the opening amount of the valve core, and the more obvious the asynchrony. The diameter of the damping hole in the back cavity of the main valve core of the column hydraulic control check valve has little influence on the synchronous performance of the left and right columns, and when the valve core of the hydraulic control check valve corresponding to the column with large load is opened, there will be an impact vibration, and the valve core will open first and then tend to a smaller stable value.

In order to solve the problems of high energy consumption and low efficiency of mine drainage system, the optimization design of mine cascade drainage system is carried out based on particle swarm optimization (PSO) algorithm. According to the cascade operation theory of two different types of centrifugal pumps and the proportional law of speed regulation by frequency conversion, the relationship between the flow and head of the main drainage pump and the speed of the booster pump is deduced. Taking the efficiency of drainage system as the optimization objective, the extreme value is optimized by PSO algorithm. Under the rated speed condition of the booster pump, taking the current, voltage and power factor of the main drainage pump motor and booster pump motor, as well as their outlet pressure and flow as the initial parameters, the theoretical extreme value of the total efficiency of the drainage system is obtained by limiting the number of iterations, and the optimal speed of the booster pump is determined. Its feasibility is verified by the speed regulation experiment by frequency conversion. The results show that the proposed method for determining the optimal speed of booster pump has high speed regulation accuracy, which can ensure that the drainage system operates in the high-efficiency working condition area, so as to achieve the purpose of energy saving and consumption reduction. This research is of great significance to improve the efficiency of mine drainage system and increase the safety and reliability of drainage facilities.

In order to determine the optimal sectional coal pillar width in the mining area, on the basis of establishing the comprehensive decision-making index system for the width of the coal pillar in the section, the basic principles of the analysis at level method (AHP), the entropy method, the weighted gray correlation analysis method (GRA) and the weighted TOPSIS method are used to construct a comprehensive decision-making system for the width of the sectional coal pillar, and the comprehensive decision-making scheme of multiple sections of the coal pillar width is optimized. In the process of optimization, the weight vectors of each decision-making index are obtained by combining AHP and entropy weight methods, and combined with the advantages of grey correlation analysis method (GRA) and the ranking method (TOPSIS) method of approximation ideal solution, a comprehensive decision-making model is established to quantitatively analyze the proposed selection scheme, and the comprehensive decision-making ranking of the sectional coal pillar width design scheme is carried out. Taking the preferred coal pillar width scheme in the Fengjiata coal mine section as an example, the relative fit of the seven proposed schemes is 52.88%, 58.99%, 36.39%, 31.96%, 42.13%, 42.15% and 52.81%, respectively, and the optimal of the second scheme is determined, that is, the coal pillar width is 11m. After on-site practice verification, it shows that the comprehensive decision-making system has considerable feasibility and effectiveness, and provides a new calculation method for determining the width of the coal pillar in the section.

In view of the phenomenon of "size cycle pressure" of the working surface under the conditions of multi-layer thick hard roof in Yushen Mining Area and the strong problem of mineral pressure, this paper comprehensively uses theoretical analysis, numerical calculation and microseismic measurement to conduct a more in-depth analysis and study of the breaking motion of the working surface roof under the condition of multi-layer thick hard roof and the pressure law of the working surface. The results show that the breakdown of the middle and high key layers has the characteristics of "low frequency" and "large breakage", and is closely related to the "large cycle". The space-time superposition of the key layer of the high and low layers is an important cause of the "large cycle to press" of the working surface; The intervention control of the breaking motion of the roof of the middle and high critical layers is the key to reducing the compressive intensity and frequency of the "large cycle", and the way to achieve this can be to weaken the low critical layer or the middle and high critical layer. The research conclusions have positive reference significance for deepening the understanding of the "large cycle" strong mineral pressure phenomenon of the working surface under similar geological conditions in the Yushen Mining Area and guiding the development of follow-up system governance engineering practice.

Fault structure is not only an important geological factor affecting coal mining, but also one of the main factors inducing mine rock burst disaster. In order to quantitatively analyze and explain the coupling relationship between the fault structure and the spatial position of rock burst, taking the South Hegang Mining Area as the engineering research background, based on the geological dynamic zoning method, the fault structure in the South Hegang Mining Area is divided. Using the principle of fractal geometry, the fractal dimensions of the whole area and the sub area of the fault in the study area are statistically calculated, and the fractal geometric characteristics of the whole area and the sub area of the fault in the study area are analyzed. The results show that NW trending faults and near Sn trending faults have a high degree of control over rock burst in the southern mining area of Hegang, followed by NE trending faults, and near we trending faults are the worst. The spatial position of rock burst has a good corresponding relationship with the fractal dimension value of fault zoning in the study area. The zoning where rock burst has occurred has a large fractal dimension value of fault zoning, which is located in the area with complex and complex fault structure. The fractal dimension value of faults in different directions in the same zone is different from the rock burst, and the degree of control of faults on rock burst is also different; The fractal dimension values of faults in the same direction in different zones and the degree of rock burst control are also the same.The research results quantitatively reveal the control effect of fault structure on rock burst, which can provide new ideas for the prediction and treatment of rock burst.

In order to study the characteristics of the stress field of the irregular coal pillar left over from the upper coal and the impact on the impact risk when mining the lower coal face, and put forward targeted rock burst prevention measures, according to the methods of numerical simulation, source analysis of microseismic events and engineering analogy, when mining the 18305 working face of Jining No. 3 coal mine, outside the influence area of the upper irregular coal pillar Numerical simulation and stress analysis are carried out for different stress characteristics near the affected area and entering the coal pillar area, the influencing factors of rockburst are fully studied, and the coal rock strength weakening and anti scour treatment measures for lower coal mining in the coal pillar affected area are formulated. The research shows that the vertical stress of the coal body in the left pillar area of the upper coal mostly presents an asymmetric "saddle" distribution, forming an obvious stress concentration. With the push mining of the working face, the coal pillar area is shrinking, the peak value of vertical stress in the coal pillar area continues to rise, microseismic events are concentrated in the coal pillar area, and high-energy events occur frequently, indicating that the coal and rock mass in the coal pillar area overlaps the influence of mining stress under its own high stress state, resulting in large-scale fracture and increased impact risk. The microseismic trend analysis shows that when the working face advances to 50m near the coal pillar area, the vertical stress of the coal pillar superimposes the advance mining stress of the working face to reach the stress peak. The anti scour scheme of deep hole blasting in hard roof strata and pressure relief by large-diameter drilling of coal body during lower coal mining in the coal pillar affected area is formulated. The field practice shows that the measures of deep hole blasting in roof strata with large charge and pressure relief drilling of coal body can significantly reduce the stress level of coal and rock mass in the area affected by irregular coal pillar, It can effectively avoid the occurrence of rockburst in the area affected by deep irregular coal pillar.

In order to eliminate the influence of matrix gas seepage effect on the flow-solid coupling model and accurately describe the gas transport law in the extraction process, a two-hole dual permeability model that is more consistent with the characteristics of coal seam porous media is established, and a two-hole dual permeability flow-solid coupling model that considers the Klinkenberg effect and dy-namic gas diffusion coefficient is proposed. COMSOL was used to simulate the gas extraction process of the borehole and analyze the changes of gas transport pattern, permeability and effective extraction radius during the pre-pumping process of the coal seam borehole. The simulation results show that the Klinkenberg effect effectively promotes gas transport, and the permeability is the result of skeletal compression and matrix contraction, with the increase of extraction time, the matrix contraction dominates and the permeability gradually increases. The seepage velocity at the observation point can be divided into three stages: rapid rise, slow decline and stable and constant. The effective extraction radius of gas is in accordance with the power index function of extraction time and hole diameter. The field test basically matches with the simulation results, which verifies the correctness of the theoretical coupling model and provides a theoretical basis for gas extraction design.

The cutting load in the cutting process of boom-type roadheader cannot be measured directly, so the cutting state parameters of the machine body should be used to reflect the changes of cutting load indirectly. According to the cutting principle and cutting characteristics of roadheader, four cutting parameters, namely cutting motor current, driving cylinder pressure, cutting arm swing position and stress state of key parts, are selected, and the sensitive relationship between different cutting parameters and cutting load changes is investigated by mathematical modeling and finite element analysis. The research results show that the three parameters of cutting motor current, driving cylinder pressure and stress state of key parts are more sensitive to the change of cutting load. In the future, the integration of the above three cutting state parameters can accurately characterize the cutting load changes and lay the theoretical foundation for the research of autonomous control and fault diagnosis of boom-type roadheader.

The 31116 working face of Jinjie Coal Mine adopts the gob-side entry retention technology, and the air leakage in the gob has a large intensity and a wide range, which provides a continuous oxidation environment for the remaining coal, which is easy to cause secondary or multiple oxidation. Oxidation characteristics of leftover coal. In this paper, the low-temperature oxidation characteristics of raw coal, pre-oxidized coal, and water-soaked air-dried coal were systematically studied by temperature-programmed experiments, during the experiment, the spontaneous combustion characteristic parameters of the coal samples changed exponentially with the increase of temperature. CO can be used as an indicator gas between 30 and 110 °C, and C2H4 can be used as an indicator gas between 110 and 200 °C. Secondary oxidation The gas production, oxygen consumption rate and exothermic intensity were lower in the early stage of the reaction than in the initial oxidation, and higher in the later stage of the reaction. Compared with the raw coal samples, the temperature points at which CO and C2H4 were detected were 10~20°C earlier, the oxygen consumption rate increased by 173×10-11mol·cm3·s-1 at the highest, and the minimum and maximum exothermic intensity The highest increases were 211×10-5J·cm3·s-1 and 261×10-5J·cm3·s-1, respectively, indicating that the water immersion process has a certain promoting effect on the coal oxidation process.

In view of the problems that coal mine accidents often occur in our country, such as coal industry being affected by internal and external factors, the definition of coal mine systematic safety risk is put forward, this paper expounds the four characteristics, trigger factors and transmission mechanism of coal mine systematic safety risk. To construct the system of coal mine systematic safety risk index, including 1 first-class Index, 5 second-class index and 25 third-class index, and to establish the model of coal mine systematic safety risk index, the model was used to analyze and judge the systematic safety risk of 2021 coal mines in 23 coal-producing provinces (regions) of our country. The results show that: first, the first quarter, the fourth quarter coal mine system safety risk index is high, 0.3926 and 0.3959, respectively, higher than the national average level. Mainly due to the enterprises generally resume production, rush to catch up with the progress of construction, winter heating coal consumption increase and other factors, the coal mine systematic safety risk presents an upward trend; The systematic safety risk of coal mines in Guizhou, Yunnan, Shaanxi and Henan provinces is high. It is necessary to strengthen the supervision of coal mine safety during the above-mentioned period and in the above-mentioned provinces in order to prevent the occurrence of serious accidents in coal mines. The research results of this paper provide practical and effective theoretical guidance for the prevention of systematic safety risks in our country, and provide technical support for the supervision and supervision departments to carry out remote supervision and accurate prevention and resolution of major safety risks.

In order to improve the stability and reliability of SAC electro-hydraulic control system controller application software, the problems existing in software development unit testing are put forward, such as single software testing method, simple testing environment, low coverage rate of software development test, and can not effectively reproduce the field problems. To solve these problems, the SAC type electro-hydraulic control system is used to improve the software quality. Establish an automated test platform, describe the hardware design and software design of the test platform, collect the controller status through the data acquisition device, use the IMX6 automatic test device to carry out automatic software function test, realize the application software valve output, sensor signal simulation, real-time data acquisition and display test. Four effective automated testing methods based on function driven, data driven, boundary information and field problems are proposed, which can realize the basic function, advanced function and safety function testing of the application software, and combine the test cases and field feedback problems, reproduce the problems and find out the reasons, so as to ensure the robustness of the software and provide a theoretical basis for further realizing the automatic testing of the application software.

Transient electromagnetic signals are easily affected by electromagnetic interference, which reduces the signal-to-noise ratio of data and distorts the attenuation curve. However, a single filtering method has some disadvantages, such as easy loss of geological information and excessive smoothness, so it is difficult to obtain high-precision imaging results. Therefore, a hybrid algorithm based on wavelet packet transform -BP neural network is proposed, which makes use of wavelet packet transform's ability to extract energy features, decompose and reconstruct signals and BP neural network's learning and feedback ability to filter transient electromagnetic signals. Fourier transform is used to obtain the frequency domain characteristics of the transient electromagnetic signal, and the difference between the interfered signal and the undisturbed signal is obtained by comparing them. Using three-layer wavelet packet decomposition to obtain the energy ratio of the third-layer nodes, extracting the characteristics of the reconstructed signal, and preliminarily decomposing and reconstructing the transient electromagnetic signal; The trained neural network model is called to train the features of the reconstructed signal, and the final filtered transient electromagnetic signal is obtained. The theoretical and measured data research shows that the hybrid algorithm is more practical and accurate than the commonly used S-G filtering and mean filtering. It keeps the real geological information while filtering, enhances the accuracy of data interpretation, and has a good application effect, which provides a strong technical support for data processing.

Aiming at the problems that the fault signal of bearing with slight wear is easily submerged by strong background noise and the fault features are weak and difficult to diagnose, a fault feature extraction method for rolling bearing with slight wear under strong background noise is proposed. The bearing vibration signal was decomposed by VMD, and the optimal intrinsic mode function was accurately selected based on the maximum kurtosis. The objective was to minimize the power spectrum entropy of the optimal intrinsic mode function, and the early termination criterion was set to realize the adaptive optimization selection of VMD parameters. The early fault signals of bearings were decomposed into several intrinsic mode functions by the VMD method with optimized parameters. The intrinsic mode function with the largest kurtosis were selected for envelope demodulation analysis, and the envelope spectrum was obtained by combining with the fast Fourier transform to achieve the extraction of fault characteristic frequency. By analyzing the measured fault signals of different types of bearings with enhanced background noise, the results show that the proposed method can effectively extract the fault characteristics of the slight wear fault signal under the interference of strong background noise, and realize the accurate diagnosis of slight wear fault of bearings, which verifies the effectiveness of the proposed method.

Abstract：Coal slime flotation is one of the effective methods for fine coal slime separation. In order to explore the effect of different density of fine coal on the flotation process, this paper mixed different density of fine coal slime with different proportions into coarse coal for test. The flotation feed and gravity concentrate are used as test coal samples, and the gravity concentrate is used to prepare coarse slime and low density fine slime. The flotation feed sample is prepared into fine coal with different density by flotation and sedimentation test using organic heavy liquid. Under different mixing ratios, the best dosage test was carried out first, and then the flotation speed test was carried out for different flotation feed with the best dosage. Through the test, it is found that the effect of low density fine coal on flotation is not obvious; When medium-density fine-grained coal exists, the effect on the flotation speed of coarse coal is not as obvious as that of low-density fine-grained coal; High-density fine-grained coal will greatly reduce the quality of flotation clean coal through entrainment.

In the process of underground coal gasification, especially in the dry distillation zone, the organic substances generated by pyrolysis will cause potential pollution to the surrounding aquifers, which seriously restricts the industrialization of underground coal gasification. The coal samples were subjected to slow pyrolysis at different end temperatures from 200°C to 600°C. This experiment can simulate the pyrolysis reaction under the oxygen-free condition in the dry distillation zone of gasification channel distillation, and explore the variety and content of typical organic substances produced by coal pyrolysis. The results showed that the highest content of oxygenated compounds in the pyrolysis products was 36.19% at a pyrolysis temperature of 200°C, with the increase of temperature, the content changes slightly. The phenolic compounds increased with the increase of pyrolysis temperature, and the content reached 17.97% at 600°C. The content of aromatic hydrocarbon compounds in raw coal is relatively high. When the temperature is higher than 300°C, a large amount of aromatic hydrocarbon compounds begin to release. The proportion of aromatic hydrocarbon compounds in the total pyrolysis products is relatively high. A large amount of aliphatic hydrocarbon compounds were produced by pyrolysis at 300°C. With the temperature increasing, the content of aliphatic hydrocarbon compounds decreases continuously. At 600°C, the content of aliphatic hydrocarbon decreases to about 10% of the total products.

Coal gasification is the key basis of low-carbon and clean utilization of coal, but the discharge of fine slag solid waste has become an important factor restricting its development, which needs to be dealt with cautiously through reasonable, efficient and clean comprehensive utilization means. The production mechanism and main characteristics of fine slag are introduced in this paper. The recent research progress of fine slag in building materials (cement, building bricks, wall materials, concrete), high value-added materials (silicon-based mesoporous materials, carbon-silicon com-posites, sialon ceramics, adsorption materials) and combustion are reviewed. It is pointed out that the residual carbon and the amorphous silicon and aluminum oxides in fine slag are the material basis for resource utilization and high value-added utilization of fine slag, and then the value and importance of pre-carbon ash separation for high value and deep processing and utilization of fine slag are analyzed. The effects of foam flotation, gravity separation and sieving (classification) on carbon-ash separation of fine slag are discussed, and it is pointed out that the fine particle size distribution, high porosity structure, and the mutual intercalation, melting and coating between residual carbon and ash are the main factors leading to the difficulty of comprehensive utilization, high processing cost and large-scale utilization difficulty of fine slag. Based on the existing re-search and application practice, it is put forward that optimizing the coal gasification process and corresponding equipment, improving the carbon conversion efficiency as much as possible and reducing the enrichment of residual carbon in solid residue are essentially the ways to solve the problem of treatment and disposal of fine slag. For the stock problem, it is appropriate to adopt clean, environmentally friendly, low-cost landfill technology, soil remediation technology, building materials technology and other large-scale verification methods. In addition, the high efficiency separation technology and the high performance materials preparation technology should be verified by further scientific research and demonstration, and their utilization scope should be expanded by means of policy and market guidance, so as to realize the development of related advantage technology from laboratory to industrialization, and finally solve the problem of treatment and disposal of fine slag.

In order to improve the stability and synchronization of the left and right tracks of the mining EBZ220 roadheader, this paper expounds the working principle and load characteristics of the roadheader driving control system, analyzes the influencing factors of the roadheader driving deviation and the theoretical calculation of the deviation, designs the key technologies such as the electro-hydraulic synchronous driving control strategy based on the PID control algorithm, the wheel side speed measuring device and the intelligent driving system, and the test results show that, The average angular velocity of the left track of EBZ220 roadheader is 0.554rad/s, and the average angular velocity of the right track is 0.553rad/s. The driving synchronization of the left and right tracks is good, and the deviation meets the coal industry standard of the roadheader, which provides a reliable driving technical scheme for the development of intelligent and unmanned underground rapid tunneling.

The middle transfer device of the belt conveyor in the dark inclined shaft is subject to space limitation and unreasonable design, which leads to blocking, spreading and dust pollution problems, thus establishing the mechanical model of the transfer material, using the discrete element method to simulate and compare the material transfer process of three working conditions, analyzing the discharge efficiency, conveying volume and material flow trajectory characteristics, designing a middle transfer device and summarizing the design method, and using the printing technology to pre-design and manufacture the transfer device. The design method is summarized, and the transfer device is pre-designed and manufactured by using printing technology. The results show that the middle transfer device designed by using the simulation speed, conveying volume and material trajectory has no blocking and spreading of material in the transfer process, And the design method constantly improve, optimize the structure, reduce the impact of the material on the central transfer device and conveyor belt, extend the life, with practical engineering application value.