In view of the problems of lacking technical standards and imperfect standard system in China's CBM industry, the investigation and sorting of the status of CBM technical standards comprehensively are carried out in the paper. There are 87 current CBM standards (16 national standards and 71 industry standards), which are mainly management standards, followed by method standards, less basic and product standards. The framework of CBM factual standards system is determined. Based on the current situation of CBM industry and the demand of technical development at home and abroad, the standard system of CBM in China is constructed for the first time. The main specialties of the standard system are CBM geology and resource exploration, CBM drilling engineering, CBM hydraulic fracturing engineering, CBM drainage engineering, CBM surface gathering and utilization, and CBM surface extraction in coal mine area. According to the classification design of each specialty, 59 standards (13 national standards and 46 industry standards) are planned. The standard system and planning direction of CBM constructed in this paper highlight the key fields and technical status of CBM industry, which has certain scientificity, applicability and operability. It can provide reference for the standardization of CBM at home and abroad in the future, and has important research significance.

Aimed at the problems of under wide range and the layout of the mining areas of the 4 coal and 4-2 coal seams which influenced by the surface oil pipelines in Wangzhuang Mine, the research methods that combined field measurements, theoretical analysis and empirical analogy were used. Firstly, the mining ranges under the oil pipelines were delimited, and different coal mining schemes were compared. Then the movement and deformation of the oil pipelines when single layer mining or repeated mining were predicted, finally, the feasibility of backfill mining and the impact on the safety of oil pipelines were analysed, and safety technical measures were put forward. The results showed that the deformation caused by mining had the greatest influence on the safety of oil pipelines, the maximum movement deformations (maximum horizontal deformation as 1.09mm/m, tilt as 2.10 mm/m, curvature as 0.0271×10-3/m) of oil pipelines would happen when the oil pipelines go through the middle of the repeat mining area, it is feasible for backfill mining because the maximum deformations were all within the allowable range. The most dangerous areas of the oil pipelines were the range of 190m on both sides of the boundary of the repeat mining areas that should pay more attention during mining, and it was necessary conditions for safety and stability to ensure the filling percentage greater than 86%.

Based on the production capacity and geological conditions of Xiaobaodang Coal Mine, the goal is to construct gangue backfilling technology and green mines. Through analysis and comparison of the existing gangue filling technology, this article put forward the overall plan of gangue filling in Xiaobaodang Coal Mine, combined with its production forecast. According to underground gangue separation, core issues such as filling area and filling technology were researched. The result indicated that the gangue-filling plan that transporting by explosion-proof rubber-tyred after underground separation and filling in NO.1 mine shaft crossheading and belt conveyor roadway of abandoned workings, as well as in NO.2 mine filling area using Wongawilli mining method could achieve the goal of gangue backfilling technology and green mining in Xiaobaodang Coal Mine. Key Words: green mining; coalgangue; filling; filling technology

Permanent magnet assembly elevator as domestic emerging ascending technologies, in order to explore techniques of energy conservation and efficiency, with the background of the selection of the auxiliary inclined shaft lifting system in zhengling coal mine, on the basis of wellbore and parameter, use of the equipment type selection manual about the elevator and motor regulation calculation, the selection JKN-3.5×2.5P permanent magnet assembly elevator, form a complete set of 660 v, 710 kw permanent magnet synchronous motor; And through the lifting system diagram, the lifting system kinematics, dynamics system analysis, the results meet the requirements of lifting. The key to improve the system power is calculated, compared to traditional elevator analysis: model number, motor power, improve speed and improve working conditions at the same time, the permanent magnet assembly elevator, compared with traditional promotion machine has the motor equivalent capacity and years about 9% lower power consumption, energy saving efficiency is good, shift quality systems are smaller and the characteristics of high safety and reliability operation.

The selection of the transverse stiffness of the conveyor belt is very important for the design of the pipe belt conveyor. Base on the study of the relationship between the troughability, the form force or the contact force of the idler and the transverse elastic modulus of the belt, the computer simulation of the contact relationship between the pipe conveyor belt and the idler use the ABAQUS software. The forming force coefficient and contact force coefficient are defined to characterize the influence of belt transverse stiffness on contact force. This paper analyzes the relationship between the contact force and gravity of the common belt conveyor, and gives the estimation method of the Artificial friction coefficient of the pipe belt conveyor.

In order to show the complex roadway system in the coal mine in an intuitive and three-dimensional way, help designers to understand the engineering situation comprehensively and accurately, and improve the design accuracy. Through extensive investigations on the application of BIM technology in the coal industry at this stage, taking the underground water pump house of coal mine as an example, the design process and ideas of 3D modeling of the underground water pump house based on BIM design software are discussed, and established the pump house chamber model, pipeline model and equipment model, and assigned corresponding attributes to the model. On this basis, reference assembly and rendering of each model are introduced, and the function and purpose of the created model are introduced, which reflects the advanced nature of BIM technology. Related application research provides a reference for the implementation of BIM technology in the coal industry.

Building Information Modeling (BIM) is a management tool which integrates design, construction and later management. Forward design is relative to “turnover design” which is to build three-dimensional model on the basis of traditional two-dimensional CAD design. Turnover design is of low design efficiency, and cannot give full play to the advantages of BIM technology. BIM forward design refers to the improvement and transformation, technology research and development and original design of complex products and systems guided by systematic engineering theory, method and process model. From the initial stage to the project delivery stage, it is completed by the BIM 3D model. It is designed directly in the 3D environment, and the drawings required are automatically generated by using the 3D model. The model data information is consistent and complete. This paper studies the application and forward design process of BIM technology in surface production system of open-pit coal mine by using Bentley 3D collaborative software and taking the coal production supplement and improvement project of Yimin open pit mine as an example. The method of applying BIM technology to the surface production system of open-pit coal mine is established, and the system of all specialties in the collaborative platform is formed. The practical project shows that, compared with the traditional 2D design, BIM technology is applied to surface production system of open-pit coal mine, which is conducive to promote the development of informatization and digitization of open-pit coal mines. The problems are exposed in the design process by collision inspection, avoiding problems in construction, improving design quality and design efficiency, reducing design changes, greatly shortening the construction period of the project and effectively reducing the cost. Because of the accuracy of 3D model calculation of project quantity and more accurate engineering basic data, open-pit coal mine enterprises can calculate the project quantity more accurately, get more precise project cost, and provide data support for the later management of the project. It can help make more accurate personnel, materials and mechanical plans for projects, thus avoiding waste of human resources, warehousing links and logistics transportation, improving the project management level, effectively controlling project management costs, giving full play to the advantages of visualization, design coordination, accuracy and optimization of BIM forward design. With the development of BIM forward design standards and relevant specifications in the coal industry in the future, and encouraged by national policies such as digital mines and smart mines, the 3D forward design of BIM technology will certainly get rapid development.

Abstract: In order to avoid the water disaster accident of super long freezing and natural thawing of water rich shaft in Balasu coal mine, the natural thawing trend of super long freezing of water rich shaft was analyzed, and the perforation grouting technology was used to block the vertical water channel in the annular space outside the freezing pipe. The engineering example shows that the freezing wall thaws slowly under natural thawing, and has difference. The shortest time for the temperature of freezing wall to rise to 0 ℃ is about 30 days; the perforating grouting operation can be carried out only when the temperature reaches above 5 ℃ for 7 consecutive days, and the shortest recovery time is about 40 days; the actual average grouting amount of a single hole is much larger than that of freezing management theory. Through the analysis of natural thawing trend of super long freezing in water rich shaft and the application of grouting technology, the freezing pipes in water rich shaft of Balasu coal mine are well compacted and there is no water flow phenomenon.

Based on the engineering background of the influence of upper left boundary pillar on floor coal and rock mass during the mining of coal seam group, the surrounding rock control technology of roadway abnormal stress section under the influence of upper left boundary pillar is studied through a series of methods such as theory analysis, refined numerical simulation analysis, field industrial test and ground pressure monitoring. The results show that: the vertical stress mainly affects the zone that below the central axis of the left boundary coal pillar, and the maximum vertical stress is about 13 MPa. The maximum horizontal stress is only about 3 MPa and it is as an auxiliary stress. The maximum shear stress is about ± 6.5 MPa and this stress mainly affects the zones that below the sides of the left boundary coal pillar; the numerical simulation results show that the difference of main stress of roof is about 9.5~10.5 MPa, and that of floor is about 8.5~9.5 MPa, and it is mainly concentrated in the position that below the central axis of the left boundary coal pillar. The shear stress of the roof is about 6.0~7.0 MPa, and the shear stress of the floor is about 5.0~6.0 MPa, and it is mainly concentrated in the position that below the sides of the left boundary coal pillar. The results of theoretical calculation and numerical simulation are in good agreement; the distribution of deviatorial stress of surrounding rock in abnormal stress section of roadway during the subsequent mining period of 051606 working face presents an overall asymmetric shape, and asymmetric reinforcement and repair measures are adopted. The ground pressure monitoring shows that the overall deformation of surrounding rock is well controlled, which can well meet the needs of safety production.

Aiming at the characteristics of Zhaozhuang Coal Industry roadway with high in-situ stress, soft rock composite roof, large section and large roadway deformation during mining, a full section high-pretension anchor cable support technology is proposed. Using indoor experimental tests, field tests, and borehole peeping methods, the in-situ stress of the No.3 coal seam and the properties and structural characteristics of the roadway roof rock layer and the mechanical characteristics of the coal and rock masses were clarified. The supporting parameters of anchor cable were determined by numerical simulation method, and the field industrial test was carried out. The results show that the maximum buried depth of No.3 coal seam in Zhaozhuang Coal Industry is over 850m, and the lateral pressure coefficients of the maximum and minimum horizontal in-situ stress are 1.33 and 0.58, which are typical high stressed coal seams. The immediate roof of No.3 coal seam is interbedded mudstone and sandstone, with relatively developed fractures and low rock mass strength. It is a typical soft rock composite roof. High pretension full anchor cable support technology can better control the surrounding rock deformation of roadway. After timely application of reinforcing anchor cable and grouting reinforcement measures in key areas, secondary reusing of the gateway hardly needs secondary repair, thus ensuring safe and efficient stoping of the working surface. The successful application of full section high-pretension anchor cable support technology in Zhaozhuang Coal Industry can provide references for the control of surrounding rock of large deformation roadway under similar conditions.

In order to realize the safe, efficient and economically withdrawal of working face, taking 22206 fully mechanized working face of Buertai coal mine as the engineering background, the grouting reinforcement technology for the retracement channel of working face was proposed by combining theoretical analysis with field measurement. By establishing the mechanical model of the residual coal pillar at the end of mining, the stability of the residual coal pillar is analyzed and the appropriate width of the residual coal pillar is determined. When exploring the mechanism of grouting reinforcement, through comparing the experimental results of uniaxial compressive strength, it is concluded that grouting reinforcement technology has significantly improved the bearing capacity of coal and rock mass. Finally, combined with the specific situation of 22206 fully mechanized working face in Buertai coal mine, the optimal grouting time in the main withdrawal channel during the final mining period is determined as 10.1m width of the remaining coal pillar. The results are applied to engineering practice and the expected effect is achieved. The results show that the polymer reinforcement material injected into the front side and roof of the main retracement channel during the final mining period can effectively control the stability of the coal pillar and roof, and realize the safe, efficient and economically moving and toppling face.

Aiming at the current situation that the effective drainage length of cross-layer boreholes in the current construction of Zhaozhuang Coal Industry is short, explore the construction technology practice of cross-layer directional long boreholes to further increase the effective drainage length of cross-layer boreholes. To this end, the existing 4500 drilling rigs are used to support spiral grooved cable drill pipes, screw motors, and measurement while drilling equipment. Three bottom-draining lanes, 3318, 2312, and 1319, have been used to carry out cross-layer directional long drilling construction and hole protection technology tests. , A total of 78 drilling holes were constructed, with a total footage of 11205m. Optimization: During the directional drilling process, for the soft coal collapsed area, it is necessary to replace the triangular drill pipe + φ113mm drill bit for rotary reaming; after the directional long drilling is completed, the supporting hollow drill pipe + open-close drill bit is used. The lower screen pipe protects the hole in the full-hole section to ensure the unblocked drainage channel. Practice has shown that the longest hole depth of cross-layer directional drilling reaches 150m, and the longest hole depth of single-hole coal seam section reaches 120m. The coal gangue ratio of long cross-layer directional drilling increases to 1:0.51, and the flow rate of 100-meter drilling increases by 1.35~2.5 Times. The improvement of the drainage length and the drainage efficiency of the through-bed boreholes provides a technical reference for reducing the number of bottom-draining tunnels in the soft coal seam working face.

The No. 6 coal seam in the west of Jungar Coalfield is threatened by the double threat of ordovician limestone water on the floor and sandstone water on the roof. Hydrogeological conditions are complex and water disasters occur frequently. It severely restricts the safe and efficient mining of coal. The characteristics of water damage in Jungar Coalfield are analyzed. Using underground ultra-long directional borehole drilling technology and roof water damage to carry out drainage method. The vertical water channel can be cut off by combining the exploration and sealing of karst collapse column and crack in coal floor. The optimal selection of target horizon, borehole trajectory control, borehole grouting technology and borehole construction are studied. The application research is carried out at 61605 working face of Longwanggou Coal mine in Jungar Coalfield. The depth of the hole is generally more than 1100 meters, and the maximum hole depth is 1227 meters. The grouting effect of each borehole reflects the development of fracture and that of outlet borehole is basically the same. Local fissures develop. Grouting reinforcement was carried out in the area where cracks may exist. No large water passage and strong water-rich area were found.Good effect of water disaster prevention and control has been achieved.Safe and sustainable coal mining has been achieved.

In order to find out the water richness of the coal seam overlying rock in the Ordos ancient gully basin, and to understand the hydrogeological conditions of the overlying rock in the ancient gully basin, based on the analysis of the characteristics of the transient electromagnetic field of the overlying rock, the ground transient electromagnetic method was used to conduct an experimental study. Optimized tests such as instrument consistency check, background noise investigation and parameter selection were carried out, and then based on the test results, the water-richness of the Quaternary strata, the Jurassic-Cretaceous strata, and the 4-2 coal seam in the ancient gully basin was carried out. Analyze the detection results from multiple angles such as points, lines and surfaces. The results show that the electrical properties of the stratum in the Ordos ancient gully basin from shallow to deep show a stable "medium (low) resistance ~ high resistance ~ low resistance" K-shaped characteristics; The optimized parameters of the transient electromagnetic method are the emission frequency of 25Hz, the gain of 1×, and the side length of the square emission wire frame is 240m; The survey of the overlying rock in the ancient gully basin revealed that the apparent resistivity of the Quaternary strata was generally low, and the water richness was relatively strong-medium, while the overall apparent resistivity of the Jurassic-Cretaceous and 4-2 coal seams was relatively high , Weak or not rich in water.

This paper mainly focuses on the problem of hydraulic support rotation, which frequently occurs in production period of 8.8 m ultra-high working face in Shangwan Coal Mine. Firstly, this paper analyzes the causes of support rotation, and it is considered that the essence is that there is a moment M acting on the support, which makes the support rotate. Secondly, it analyzes the adverse effects of the support rotation, and thinks that if the support rotation degree is heavy, it will affect the adjustment of the size of two ends' exit of the working face. Based on the essential reason of the support rotation, dynamic adjustment method for rotated support is proposed, which refers to applying a moment M' in opposite direction to the rotated support, and operation methods and matters needing attention in four common cases are explained. At the same time, combined with the actual production conditions of high head and low tail of working face and by analyzing the force ,which acting on the moving support, it is considered that restrict upper right pushing jack of support shield beam to extending is good for avoiding support rotation. The effect of the proposed adjustment methods is obvious in actual application, which is of great significance to improve the overall engineering quality of working face.

Analyzing the pressure monitoring data of working face supports is an important method for studying the laws of mine pressure. However, due to the lack of description of roof structure and roof migration characteristics, it is impossible to accurately grasp the specific causes of abnormal mine pressure, and effective measures cannot be formulated in time to ensure roof safety. This paper takes the 5302 working face of Changping Coal Mine as the research background. On the basis of traditional mine pressure monitoring technology, micro seismic monitoring technology is introduced to realize the analysis of the roof activity law of the working face. Through the analysis of support pressure, roadway surrounding rock stress and strain, roof breaking energy Analysis of multi-source data such as events, study the specific causes of abnormal underground pressure such as insignificant pressure on the working face, roof spraying, large roadway deformation, etc., try to explain the causes of abnormal underground pressure from different angles, and analyze the working face and roof Management has important guiding significance.

The weak cemented rock mass is easy to soften and degrade when encountering water. It is difficult to judge the boundary between the collapse zone and water-conducting fissure zone accurately by using the traditional observation of water injection and TV observation of borehole, and the drilling hole is easy to collapse, and the television imaging of drilling is relatively fuzzy. Taking the New Shanghai No. 1 coal mine as an example, through disintegration tests and rock mechanics tests under different water content, it is concluded that mudstone is cemented and sandstone disintegrates when it meets water, and its strength decreases with the increase of water content. The saturated uniaxial compressive strength of mudstone is mostly less than 20MPa, the uniaxial compressive strength of sandstone between 0 and 70MPa, and the overburden type is classified as medium. By means of distributed optical fiber and parallel electrical method, the development height of caving zone and water-conducting fissure zone of No.15 coal seam are 46.7m and 75m respectively, the caving mining ratio is 12.62, and the fracture mining ratio is 20.27. Compared with the numerical simulation result and empirical formula, the measured value of caving zone is larger than the predicted value, the measured value of water-conducting fissure zone is larger than the numerical simulation result, and it is smaller than the empirical predicted value. In the "Three-under" Mining Guide, there are few measured samples of weakly cemented soft formations, and the research results can provide data references for similar mines, and also provide technical monitoring methods for the failure of weakly cemented soft formations overburden.

Grouting technology has become one of the main methods for the treatment of goafs, especially deep goafs. At the same time, it has a good application effect in slope reinforcement, foundation treatment, and underground engineering anti-seepage and water blocking projects. The grouting project in the mined-out area, especially the deep strip mined-out area, has greater concealment and complexity. Most of the inspection indicators given by the specification can only be used to evaluate the grouting effect after the construction is completed, and cannot be used during the grouting process. Guiding quality control, the evaluation work lacks timeliness and comprehensiveness. In order to scientifically evaluate the grouting effect of the goaf in the deep strip, based on the in-depth analysis of the current commonly used grouting effect detection methods, combined with engineering examples, the three key factors that directly affect the grouting quality of the goaf are material, grouting and grouting. The link discusses the key points of the construction process control, and uses the grouting process analysis method, the inspection hole method, the deformation monitoring method and the geophysical method to detect and evaluate the grouting effect, forming a comprehensive inspection and evaluation method of "instant inspection + post-construction inspection" to achieve the comprehensive analysis and evaluation system from point to surface and qualitative to quantitative has certain guiding and reference value for similar projects.

The mining of high gassy and inflammable coal seam is faced with the double threat of gas and spontaneous combustion, and the Y-type ventilation mode aggravates its risk degree, and the accurate division of the scope of coupling disaster is the key to prevent accidents. In qinglong coal mine 21606 working face as an example of Y type ventilation goaf under the numerical model is established, using COMSOL software of gas concentration field of goaf flow field is simulated, in goaf leakage wind flow field and gas concentration field distribution on the basis of coupling of gas and spontaneous combustion disaster areas were divided, and through the SF6 gas experiment simulation results are verified.The results show that the risk area of spontaneous combustion in goaf distributes in L-shape from the return side to the inlet side;The gas accumulation area is located in the deep, upper corner and vertical vent of the goaf; The coupling disaster area is located 20 ~ 70m behind the working face and at the vertical vent. Hrough comparative analysis, the results of SF6 tracer experiment are basically consistent with the results of numerical simulation, which verifies the reliability of the numerical model and provides technical support for the division of goaf gas fire coupling disaster area.

Urban buildings have the characteristics of large architectural style differences, high protection level requirements and dense distribution. Therefore, compared with village coal mining, overlying rock control requirements are higher and more difficult. This paper takes coal mining under the town of Tangshan mine as the research object, based on the mining conditions and production practices of the mine, the concept of “backfilling-keeping” method (B-K) is proposed. It is revealed that under the conditions of different filling rates and backfilling and keeping ratios Variation patterns of overlying rock and coal pillars using numerical simulation methods. The results show that the use of “backfilling-keeping” method meets the control requirements of the roof and overlying rock when the filling rate is not less than 80%. When the filling rate is 80%, the roof failure height is 1.4 times the mining thickness. The peak stress is 43.8MPa and the stress concentration factor is 2.19; when the pillar width is 105m and 90m, the vertical stress peak value of the coal pillar is smaller and the stability is better; the field implementation effect shows that the filling rate is 80% and the pillar width is 90m , the stent pressure distribution is balanced, the village impact is slight, and the application effect is good. The research results can provide reference for coal mining with higher protection level of protected objects.

The overburden failure law of fully mechanized top coal caving face with large dip and extra-thick coal seam has an important influence on the characteristics of mining pressure, and it is one of the main reference indexes for the selection of working face support and roof management. Taking the Fenyuan coal industry in Ningwu mining area as the background, the KJ1160 microseismic monitoring system was used to study the microseismic events and energy distribution characteristics of high-dip fully mechanized caving faces. The development of roof cracks and overlying rock movement laws of working faces were studied by establishing a physical similarity simulation model. The commonly used "three-zone" calculation formula is used to check the damage height of the overlying strata in a fully mechanized caving face in a large-dip and extra-thick coal seam. The research results show that: the overburden caving zone and crack zone of the roof of the working face with large dip angle and extra-thick coal seam form a "high up and down low" pattern in the coal seam tendency, showing hysteresis in the strike; the height of the overburden caving zone is about 60m , The height of the fracture zone is about 160m; the inclination of the coal seam is greater than 30°, and the length of the working face should not exceed 120m.

In order to study the difference of periodic overburden pressure between the top cutting and unloading self driving mining method and the conventional longwall mining method, this paper adopts the high-precision ESG microseismic monitoring system, and takes the s12012 of lingtiaota coal mine as the engineering background, and studies the periodic evolution of overburden fractures based on microseismic events and energy distribution under the influence of mining by setting up the microseismic monitoring system on site Mechanism and spatial dynamic evolution characteristics of microseismic events. The research shows that: according to the distribution characteristics of microseismic events, the periodic fracture law of overlying rock fracture under roof cutting and unloading is determined, and the fracture evolution of stope can be divided into germination period, development period and high tide period. The periodic fracture and failure of overburden can be divided into the early stage of periodic mining, the middle stage of periodic mining and the end of periodic mining. Combined with the strata behavior law of the mine, the periodic weighting step distance is 19.83m. This paper puts forward an idea of using the accumulated microseismic energy value during periodic weighting as the criterion of roof fracture and failure, and determines that the leading influence distance of working face is 10 ~ 15m by using this criterion.

In order to study the overburden failure and hydrodynamic evolution law of gently inclined and close distance coal seam group mining, and prevent water inrush disaster in the mining process, theoretical analysis, comparative analysis, similar simulation and other research methods are used to study whether the water resisting coal pillar is reserved in the working face and the formation of water inrush channel after the aquifer is pressurized. The results show that: 1) without water resisting coal pillar, the damage scope of overburden rock will expand with the mining of L1614, L1615 and L1616 working faces, and the repeated roof failure will form water conducting fissures connecting the working face and K3 and K4 aquifers; 2) after setting 32.9 m, 47.9 m, 59.2 m wide water resisting coal pillars in L1814, L1815 and L1816 working faces respectively, the water conducting fissures only lead through K4 aquifer; 3) K3 aquifer plus 3 When the water pressure is twice the initial water pressure, the hydrostatic pressure of the separated layer below exceeds the ultimate shear strength of the lower stratum, which breaks through the lower stratum and connects with the water conducting fracture zone to form a water inrush channel.

Aiming at the problem of large deformation of surrounding rock of high stress coal roadway affected by multiple mining-induced effect, 1209 material roadway of Zhongxing Coal Industry Co., Ltd. was selected as the research object. By using the methods of field investigation, numerical simulation and field test, the abnormal pressure behavior characteristics of surrounding rock of the roadway under the condition of multiple mining-induced effect were analyzed, and the variation characteristics of high stress of surrounding rock under the condition of multiple mining were simulated. This paper put forward a combined support system with roof and coal sides intensive prestressed cable truss as the core, and carried out industrial test on site. The field mine pressure monitoring results show that the deformation of roadway surrounding rock is small, which effectively ensures the stability of roadway surrounding rock, and has a certain reference value for the stability control of roadway surrounding rock under similar conditions Value.

Most shallow coal seams are characterized by shallow buried depth, thin bedrock, thick topsoil and so on. After coal mining, the overburden caving failure characteristics, roof weighting strength and the resulting surface movement and collapse damage are more serious. In this paper, the experimental working face of a shallow buried mine in Erdos of the Yellow River watershed is taken as the research breakthrough point, and the in-depth research and analysis are carried out through the field measurement and analysis of roof disaster weighting characteristics, the simulation experimental study of overburden failure and surface subsidence development mechanism, and the main technical means of probability integral calculation and geophysical supplementary exploration, This paper comprehensively reveals the characteristics of high roof weighting behavior intensity, unobvious roof weighting period, sufficient roof caving, lagging surface subsidence in goaf and remarkable collapse range in shallow coal seam mining. At the same time, it establishes the classification index of land destruction and realizes the division of land destruction area in different grades, In addition, the technical scheme of treatment engineering and reclamation engineering of mining subsidence affected area are put forward for the special suspended area, which has good reference significance for the related research of similar mines.

Aiming at the requirements of underground LED lighting equipment for the reliability of low-voltage DC power supply, a buck-type composite H-bridge topology was used to design the rectifier stage of the AC-DC converter, so that the rectifier stage can participate in unit power factor rectification and achieve Suppression of Ripple Disturbances. In this paper, the working principle and equivalent circuit model of Buck-type hybrid H-bridge rectifier are analyzed in detail, the switching state function of the actual controlled variable is derived, and a voltage feedforward decoupling control strategy is proposed. The key parameters of the circuit are designed. Finally, simulations verify the correctness of the control strategy and the parameters of the decoupling circuit.

Aiming at the problems of excessive local impact and serious wear of the receiving conveyor belt, the mechanical model of the unit coal in the curved transfer chute and the energy conversion relationship are used to obtain the transport conditions and structures that affect the abrasive wear and erosion wear of the receiving conveyor belt parameter. Through the Archard wear model in EDEM software, the dynamic simulation of coal transportation conditions with radii of curvature of 5000, 5500, 6000 mm and discharge conveyor belt speeds of 4.64, 5.8, and 6.96 m/s was carried out. According to the wear evaluation parameters, it is shown that when the radius of curvature is 5000 mm, the erosive wear of the receiving conveyor belt after coal transfer is low, and the abrasive wear caused by the rolling of coal is small; when the unloading conveyor belt When the speed is 4.64 m/s, the difference between the speed of the receiving conveyor belt and the partial speed of the coal in the horizontal direction and the partial speed of the coal in the vertical direction of the receiving conveyor belt are both small. The erosion wear and abrasive wear of the material conveying are low. Therefore, when meeting the requirements of actual working conditions, reducing the radius of curvature and the speed of the unloading conveyor belt can reduce the erosion and abrasive wear of the coal on the receiving conveyor belt and prolong the service life of the conveyor belt.

Uniform corrosion-methods of immersion testing, image-representation with scanning electron microscope (SEM)，energy disperse spectroscopy(EDS) and polarization curve was used to study the anti-corrosion property of concentrate fluid used for powered support on carbon steel in Shanbei coal mine water. The corrosion behavior of 15# carbon steel in mine water was analyzed，and the anti-corrosion property and mechanism of concentrate fluid on 15# carbon steel was studied. The results showed that the 15# carbon steel would corrode in typical mine water within 0.5h. But it would keep bright in typical mine water with 3% concentrate fluid within 720h, and the ratio of anti-corrosion was 99.27%.The concentrate fluid had a suppressing effect on anodic reaction and made corrosion potential of 15# carbon steel deviate positively about +350mV, and the ratio of anti-corrosion was about 95.38% in weak polarization region, and decreased the current density about 2～4 orders of magnitude in strong polarization region, the polarized current density would be less than 0.01mA/cm2,when polarization potential?of 15# carbon steel in typical mine water with 3% concentrate fluid was 0～700mV(vs.OCP).

In order to satisfy the high performance concrete of C80 used in frozen shaft wall, scene matching test is used to study the grading characteristics of mechanized sand, C80 concrete slump, extension ratio and compressive strength. The experimental results show that the C80 concrete with the ratio of G3 has good performance and strength under the condition of washing limestone machine-made sand with the stone powder content of 5%.. According to this result, the strength of HPC measured by field sampling is 1.15 times higher than the design value after the C80 concrete sidewall proportioning pouring is carried out.

In order to explore and develop the deep coalbed methane(CBM) and to explore the fracturing process applicable to the development of deep CBM wells, hydraulic sandblast injection fracturing, continuous tubing bottom seal dragging fracturing, hydraulic sandblast injection with large displacement composite fracturing and in-segment multi-cluster directional injection with bridge plug segmental fracturing technologies were used to fracture deep CBM wells in the Heshun Hengling block, based on the fracturing results and production test results, it shows that: The success rate of segmental fracturing by multi-cluster directional injection with bridge plug in the segment is high, by adopting the "close cut" transformation method, the volume of reservoir transformation is significantly improved, the contact area between the fracture and the reservoir is larger, and the reservoir has a stronger ability to supply fluid and gas to the fracture and the wellbore，so it is recommended as the main fracturing method for deep CBM horizontal wells.

This paper introduces the current status of inspection standards for permanent magnet synchronous variable frequency speed-regulating motors for mines. Combining the characteristics of permanent magnet synchronous motors with low speed and large torque, frequency converter starting and speed regulation, etc., the motor performance inspection program and inspection items are proposed. The inspection method and measurement method are different from those of the self-starting permanent magnet synchronous motor. The trial results show that the inspection items and measurement results can accurately and effectively reflect the performance of the permanent magnet synchronous variable frequency speed control motor.

In order to solve the problem of multi-layer superposition of shearer power supply cable caused by multiple round-trip operation of shearer in fully mechanized mining face, the comprehensive matching technology of automatic towing cable of shearer was put forward, and the operation principle of automatic towing cable was analyzed. Taking 43102 working face of Shendong Yujialiang Coal Mine as the research object, the mechanical system and electrical system were designed, and the matching structure of vertical layout of chain path was put forward. The key technologies involved in the system, such as overload protection technology, speed and torque cooperative control technology, were designed and studied. The field application showed that the system had been running smoothly for more than 2 months, and the cable automatic towing was flexible and reliable, which could completely replace manual operation to realize the automatic management of shearer cable on-site in mining face.

Government regulation, industry competition, entrepreneurial orientation, organizational vigilance, etc. are the main influencing factors of coal enterprise mergers and acquisitions。Based on the definition of the variable and structure, the system dynamics trend simulation technology is used to construct complex feedback system. According to system dynamics research, the framework establishes an overall flow graph model and a model reason tree for each link of the system. Further, we also defined the main state variable equations, rate variable equations and auxiliary variable equations in the mode. Then, we used the Vensim software to simulate and analyze the dynamic behavior of each variable, and the overall development trend of each influencing factor for the long-term performance of the enterprise was simulated. The study found that the long-term performance level of coal enterprises showed a slow growth trend in the future without considering the introduction of any variables into the system model. For the comparison of the influence of different factors on the long-term performance of coal enterprises after mergers and acquisitions, the organization's alertness has the greatest change in the development trend of long-term performance system, followed by the role of entrepreneurial orientation, industry competition and government regulation.