Aiming at the optimization design of mine area prevention and control of rock burst in cooperative mining of double coal seams, based on the specific engineering conditions of Taohutu Coal mine in Nalin He Mining area, The analysis shows that there are some problems in the current mining design scheme of the mine, such as unreasonable selection of protective layer, wrong opening or stop-mining line, some areas are located outside the protection range, loss of triangular coal, adverse recovery of protective coal pillar in the late main roadway and too concentrated mining in the early stage of the mine. In view of the above problems, from the perspective of rock burst prevention and control, this paper puts forward the priority mining of 2-2 coal seam as the protection layer of 3-1 coal, makes adjustments to the layout of roadway and working face, and gives the optimization design scheme of cooperative mining of single wing and double wing coal seam, which can effectively avoid the problems existing in the current mining design scheme. Based on mine geology and mining technical conditions, combined with relevant standards and specifications, the reasonable fault distance and lag distance of cooperative mining of two coal seams in mine are calculated: the reasonable dip fault distance is 30 m, the strike fault distance is 47 m, and the working face of 3-1 coal seam should lag behind the working face of 2-2 coal seam 1200 m.

Aiming at the problem that it is difficult to maintain the stability of the main roadway during the mining process of the working face, in order to change the shortcomings of traditional pressure relief methods in terms of pressure relief range, time and effect, it is proposed to use directional horizontal drilling hydraulic fracturing technology for pressure relief. The reasons for the high stress in the road are analyzed by a combination of theoretical analysis and numerical calculation, and the mechanism of the directional horizontal drilling hydraulic fracturing for the transfer of high abutment pressure in the working face is revealed. It is concluded that the main reason for the stress concentration in the surrounding rock of the main roadway in the working area is the violent activities such as the fracture, rotation, migration and collapse; The implementation of directional horizontal drilling hydraulic fracturing in the mining stop line of the working face can eliminate the release of dynamic pressure energy caused by the breaking of the roof after the mining stop of the working face. The rock layers in the caving zone can be broken in time to fill the goaf and reduce the risk of the stress of coal pillar, which has achieved good results in field application.

The determination of support parameters of rock burst roadway has been puzzling engineering designers. In order to achieve the quantitative design of support parameters of rock burst roadway, the author proposed a design method of support parameters of rock burst roadway based on energy calculation, which mainly includes the assessment of roadway impact risk, determination of source parameters, determination of maximum impact kinetic energy of roadway surrounding rock and determination of energy absorption of support structure. First of all, theoretical calculation, numerical simulation and laboratory tests were used to determine that the impact kinetic energy and displacement potential energy released per unit area of the upper roadway of the 13230 working face was 78.53 kJ/m2. Based on the energy calculation method, the support parameters of the upper roadway of the 13230 working face were determined. The energy absorption of the tertiary support system was 82.66 kJ/m2. Based on the energy calculation method, the support parameters of the upper roadway of the 13230 working face were determined, The industrial test of the three-level support system has been carried out in the mine. The test results show that the initial stress of the bolt (cable) is low. With the increase of the deformation of the surrounding rock, the stress of the bolt (cable) gradually increases, and then remains stable. Under the action of the high energy impact event, the stress of the bolt support structure fluctuated to a certain extent, but the deformation of the roadway was not large. The three-level support system effectively controlled the deformation and damage of the roadway under the high energy impact event, and effectively dissipated the impact kinetic energy.

To address the issues of low reliability, poor accuracy and insufficient intelligence of the existing coal mine roof rock pressure early warning technology, this study investigated a machine learning-based approach for analyzing roof pressure warning indicators on the working face. Linear regression and systematic clustering methods were employed to analyze the cyclic internal load of the hydraulic support and the periodic weighting step, respectively. A roof pressure analysis and warning model was constructed to enable automatic analysis and prediction of key indicators for roof disaster monitoring on the working face. Field application results demonstrated that the warning system exhibited high reliability, comprehensive analysis and warning functionality, and high accuracy.In the statistical analysis of roof periodic pressure actual occurrences in the demonstration mine, the prediction accuracy was no less than 90%. This system can provide important support for the prevention and control of roof disasters in coal mines.

The hypocenter height is one of the key parameters of microseismic monitoring in coal mine, which is of great significance in the monitoring of rock burst and mine earthquake and roof fracture law. However, all the microseismic monitoring stations are located in the same horizontal plane for the near horizontal coal seam, the hypocenter height error is large, which can not meet the requirements of the monitoring. In this paper, from the perspective of source solving partial differential derivatives, the mechanism of large error in hypocenter height of horizontal coal seam is analyzed theoretically, and then the concept and implementation method of microseismic joint monitoring technology of the surface-underground are proposed based on the above problems. The layered wave velocity model of ground station is studied, and the best P-wave velocity is obtained by the inversion of the blasting event. Finally, through the analysis of the microseismic joint monitoring data of Menkeqing Coalmine and Dahaize Coalmine, it is proved that the microseismic joint monitoring technology of the surface-underground has a good improvement effect on the error of the hypocenter height.

Many western mines are faced with the problem of coordinated mining of multiple working faces in shallow coal seams for balanced production benefits, which is mainly limited by the complex time-space conflict relationship and the complex characteristics of mine pressure. Based on the engineering background of Shaping Coal Mine in Hequ, Shanxi Province, this paper analyzes and optimizes the timing and spatial layout of multi-coal seam mining in the established second panel area by means of theoretical analysis and numerical simulation. It effectively guides the layout and continuation of the working face in the second panel area. The results show that: (1) The numerical simulation analysis of panel scale realizes the quantitative analysis of mining response of different mining schemes, and the overburden structure of repeated mining determines the influence angle of lateral mining. (2) The 13104 working face of Shaping Coal Mine needs to be continued after the mining of 9201 and 9202 working faces, which has no obvious effect on 10201. (3) In order to ensure the sequential replacement of fully mechanized caving face during coordinated mining, it is necessary to adopt the technology of gob-side entry driving with roof cutting and pressure relief. The given space-time coordinated continuation scheme of working face guides the formulation of mine working face planning and mining plan, and provides analysis model and reference case for similar conditions of mine coordinated mining.

Because of the lack of technical data of the size of remaining coal pillar, safety mining of shallow deep and adjacent coal seam is affected by the house-pillar mining method after mining the shallow seam. Based on the geological and mining conditions of 2-2 coal seam using house-pillar mining method in third panel, Hanjiawan Coal Mine, drilling investigation, 3D laser scanning, physical and mechanical property testing, water detection in goaf, theoretical analysis and other research work have been carried out. Using technology of "goaf drilling+leakage observation+goaf water detection+dimensional laser scanning", it is obtained that roof crack development degree of the goaf column type goaf is low, roof strata are relatively complete, the parameters of coal pillar and warehouse are 7m and 8m respectively, and the height of goaf water in some areas is 0.15~0.35m. Based on laboratory test results, stability of residual coal pillar under the current condition of 2-2 coal and the stability of disturbed 2-2 coal pillar under the push off of 1-2 coal longwall working face are calculated and analyzed by relevant theories. Results show that residual coal pillars of different room and pillar mining sizes of coal 2-2 are temporarily stable under the current situation. The abutment pressure of 1-2 coal longwall face pushing off 2-2 coal room pillar goaf affects 2-2 coal residual pillar can not keep stable; The mining scheme of "mining group coal seam first, using mine pressure to destroy the residual coal pillars of coal 2-2, and then implementing the house-pillar type goaf after the upper group coal push off disturbance destruction" is technically feasible.

Power system design, the load statistics and calculation by reasonable methods, can provide an important basis for the selection of electrical equipment, transmission lines and relay protection device of coal mine power supply system, effectively support the analysis of mine power supply system, help enterprises to do a good job in construction planning, and avoid the phenomenon of repeated investment and waste. This paper takes the design of power supply system of Wangwa Coal Mine in Wangwa Coal Industry Company as an example, analyzes the content and common problems in mine power supply design from the aspects of basic data collection, calculation and analysis, the determination of the main connection mode of mine power supply and substation, equipment selection and cable selection, so as to provide experience for other engineering design.

Abstract: In coal mine shaft at the wellhead and bottom of the well, the structure form of four-corner shaft guide is often used to stabilize the lifting vessel. At present, the calculation method of horizontal force acting on four-corner shaft guide has not been reported. There is a large error between the calculation method of the horizontal force of the reference end and the measured horizontal force of the four corners of the channel. Based on this, the horizontal force of four-corner shaft guide in a super large coal mine in northern Shaanxi is tested in the field, and the calculation method of horizontal force of four-corner shaft guide in coal mine is established by using the unitary linear regression analysis model. The relationship between the horizontal force on the four-corner shaft guide acting on the lifting container and the lifting terminal load was obtained, and the formula for calculating the horizontal force on the front and side of the four-corner shaft guide acting on the lifting container was obtained. This method can provide a basis for the force analysis of the metal support structure at the shaft head and bottom of coal mine shaft and the design parameters of the four-corner shaft guide of coal mine shaft.

The informatization construction of coal washing enterprises is an extension of standardized management work, laying a foundation for the subsequent intelligent construction of coal washing enterprises. At present, there are problems in the informatization construction of coal washing enterprises, such as weak basic work, increased updates to production process equipment, cumbersome management systems, and large construction investment. In XX, 2023, the "Code for the Informatization Construction of Coal Washing Enterprises" (DB 14/1724-2023) was issued and implemented. In response to this standard, the background, significance, process, basis, and construction points of the standard formulation were explained in detail, facilitating the practitioners of coal washing enterprises to further understand the standard and further promote the informatization construction of coal washing enterprises.

The roadway engineering is the throat engineering of mining deep resources, and it is the logistics channel connecting the surface and underground space. Due to the influence of surrounding goaf, coal pillar and mining face, deep high stress roadway is often in a very complex stress state, showing various special failure characteristics. Taking the -850 m west roadway of Qujiang Coal Mine as the research object, the deformation and failure modes of roadway during mining are analyzed through field investigation, stress monitoring of bolt and anchor cable and deformation monitoring of surrounding rock. The deformation and failure of surrounding rock in deep high stress roadway under mining are divided into rear continuous ( high pressure ) deformation zone and front disturbance ( dynamic pressure ) deformation zone. According to the failure modes of different zones under mining, it is proposed to implement the ' three anchors ' combined support technology in the rear continuous ( high pressure ) deformation zone, and the support concept of combining resistance and yield in the front disturbed ( dynamic pressure ) deformation zone. The observation and analysis of the repair section show that the determined partition combined support scheme is reasonable and effective to ensure the long-term stability of deep high stress roadway under mining.

The small coal pillar roadway in the high stress environment was faced with the problems of poor stability of surrounding rock and difficult maintenance of roadway. Using laboratory experiments, field experiments and engineering practices, taking the application site of 5 m small coal pillar in 15 # coal seam of Fuda Coal mine as the background, aiming at the key factors affecting the stability of surrounding rock of small coal pillar roadway, including high in-situ stress level, poor stability of surrounding rock and drilling field goaf left in coal pillar, the technical scheme of lateral hydraulic fracturing pressure relief, stability control of surrounding rock of empty roadway and high water material filling in hidden drilling field in coal pillar is put forward, and field application is carried out. The results show that : ( 1 ) The peak initiation pressure of the key layers of hydraulic fracturing is 26.5 MPa, and the average maximum pressure of each hole is 22.3 MPa. The primary cracks in the hole are gradually opened by the extrusion of high-pressure water, which weakens the integrity of the roof significantly. ( 2 ) Based on the analysis of roadway mine pressure data, the peak stress of roof bolt is 108 kN, and the peak stress of side bolt is 86 kN, which are far lower than the yield load of bolt, and there is no anchor breaking phenomenon. The subsidence of the two sides and roof of the roadway is within the controllable range, the shrinkage of the roadway is small, and the overall stability of the surrounding rock is effectively controlled. ( 3 ) The total volume of filling high-water materials in the hidden drilling field is 682.9m3, which is higher than the total volume of the empty area of the drilling field. Each filling borehole ensures that the grouting is stopped after the slurry is returned. The filling rate of the drilling field is high, and the stability of the residual 1.5m coal pillar is good.

Abstract: In order to study the deformation and failure law of surrounding rock of gob side entry retaining at one side working face, especially the study on the reuse of gob side entry retaining, the deformation and failure law of surrounding rock at the three stages of excavation, entry retaining and reuse of single side double entry retaining at Working Face W2306 and W2307 of Gaohe Coal Mine are studied by using the research method of combining theoretical analysis, numerical simulation and engineering measurement. The research results show that the surrounding rock deformation and stress change basically take the roof center as the symmetrical structure in the tunneling stage; During the roadway retaining period, the roadway has the effect of leading bearing stress, the stability of the roadway retaining is the most damaged, and the plastic deformation of the surrounding rock is the largest; In the reuse stage, the balance of reserved roadway suffers secondary damage until a certain distance behind the working face gradually decreases and disappears.

For the construction of surface gas vertical wells for gas pre-extraction in deep coal seams, during the drilling process, it is necessary to drill through the goaf of the upper coal seam. However, it is difficult to return rock cuttings due to drilling fluid leakage for the section passing through the goaf. In order to drill through the goaf quickly and safely, it is based on the calculation formulas for the height of the collapse zone, fracture zone, and bottom plate water conduction failure zone in the "upper three zones", the depth of the well section prone to drilling fluid leakage is obtained. The optimized structure of the fourth spud well and the corresponding circulating medium used in the well section are proposed. On this basis, combined with the geological conditions of the SiHe mining area in the Qinshui Basin, the well structure design and circulating medium performance design were carried out, and a vertical well for gas extraction through the goaf was successfully implemented. The results show that for the first, second, and fourth spud sections drilling by using water-based drilling fluid systems with minimal leakage, while the third spud section is drilled by using nitrogen circulation medium, which have achieved efficient and smooth passage through the goaf at once, achieving the goal of rapid and safe completion.

In order to give full play to the role of strike long boreholes in gas control, the principle of gas extraction and relief by strike long boreholes is analyzed and summarized. By means of theoretical analysis, numerical simulation and physical simulation, the key spatial parameters of strike long borehole group are summarized and studie,And according to the working face before the initial pressure and normal production period of gas gush, roof overburden and engineering construction quality and other actual conditions,the theoretical spatial distribution range of strike long borehole group was obtained as follows: 9~50m above the top plate, 10~60m in the return air lane, spacing between drilling fields shall not be greater than 500m, and the lap distance between drilling holes in adjacent drilling fields shall not be less than 80m; On the basis of the research, The engineering practice and the effect of gas control in working face are investigated. The results showed that: The gas extraction purity of 1# drilling field is 0.29m3/min~0.75m3/min. The gas extraction purity of the 2# drilling field is 0.38m3/min~1.42m3/min; The maximum gas concentration in the upper corner is 0.7%, and the maximum gas concentration in the return air flow is 0.56%. The reasonable arrangement of the strike long borehole group in the three-dimensional space,Ensure the safety of the coal Face before the initial pressure and the normal production period.At the same time, the purpose of full drainage of pressure relief gas is realized.

This paper takes the complex mining conditions of Shendong mining area as the research object, and conducts in-depth research on the special rules of mining pressure manifestation under the goaf and the coal pillars of the section. The static load model and dynamic load model of the mining face under the coal pillars of the section were constructed. The stress calculation method of the upper coal and lower coal was derived in the static load model. In the dynamic load model, the additional load caused by the collapse of the basic top rock block of the upper coal due to the mining damage and coal pillar instability was calculated, and the influence of entering and leaving the section coal pillar on the hydraulic support force was analyzed. Based on the geological and mining conditions of the X working face of a coal mine in Shendong, a numerical simulation model was established to simulate the variation law of the coal roof pressure when the mining face entered and exited the coal pillars. By analyzing the monitoring data of the roof stress 5-10 meters in front of the coal wall, the conclusion was drawn that the stress increase of the out-coal pillar was more than 10% higher than that of the in-coal pillar. This conclusion not only verifies the rationality of the dynamic load model derivation but also provides a basis for the selection of dynamic load coefficients for entering and exiting coal pillars. The B coal pillar area that the X working face of the Shendong mine is about to pass through is treated with hydraulic fracturing and unloading measures to soften the rock layers and reduce pressure. The field measurement data shows that the resistance of the hydraulic support when entering and exiting the B coal pillar is reduced from 22333 kN in the A coal pillar area to 19616 kN, and the step distance of the periodic support is reduced from 21.7 meters to 18.28 meters, effectively alleviating the influence of pressure changes in the entering and exiting section coal pillars on the hydraulic support state. The research results of this paper have certain reference and reference value for coal mining under similar or similar conditions.

In order to complete the initial roofing of the hard roof with expanded surface by adopting the new technology of abrasive jet axis roofing, the key technical parameters of axial roofing and fracturing of abrasive jet were determined through field industrial tests in Kuangou Coal Mine, and the initial roofing scheme and project of axial roofing of abrasive jet with expanded surface were designed and carried out. The implementation process is monitored by means of hydrometer, drilling peeping and on-site observation of water discharge, and the effect of mining process is tested by means of microseismic monitoring, support pressure monitoring, coal body stress monitoring and roof caving observation. The research results show that the industrial test of prefabrication of 300mm deep fractures and 300-500mm axial length fractures with fracture radius of 5m and 10m is completed by using the axial cutting top technology of matte jet. The key technical parameters of fracture cutting and fracturing process, such as pressure, time and sand amount, are determined. The results of two processes, the implementation of the initial roof caving project and the recovery process in the expanding area of the working face of I010206 were analyzed. The results of four sections of slit in the hole, fracturing curve, fracture morphology of the hole and fracturing water showed that the whole roof seam network of the expanding surface was open. The analysis results showed the effectiveness and reliability of the implementation process of the technology project. The test and analysis of the effect of stoping process after surface expansion show that the caving situation of the first roof caving with the axial cutting of the frosted jet basically achieves the effect of the traditional blasting at the same time, the effect of the roof on the coal wall of the working face is significantly improved, the stress drop of 2.9MPa occurs in the coal body during the engineering implementation process, and the stress concentration degree of the coal body is significantly improved during the surface expansion stoping. The stress of coal body does not form stress concentration, which plays a good pressure relief effect. Through engineering practice, a new treatment mode of hard roof with wide ditch is formed.

The occurrence of rockburst in deep gob-side working faces in multiple mining areas has led to the shutdown of coal mines, making it difficult to control them. The actual effect of coal pillar retention has become an important issue affecting the safe and efficient production of these mines. Taking the deep mining in Ordos area as the background, based on the analysis of the occurrence characteristics of rockburst such as the formation structure of extremely thick bedrock, large coal pillars in the working face, and failure along the goaf roadway, the occurrence regularity of rockburst under the lateral overburden structure and load characteristics along the goaf is studied. According to the actual conditions, the distribution characteristics of lateral abutment pressure are calculated and analyzed, and the distribution of lateral abutment pressure and emergency loading failure characteristics of the working face are studied through numerical simulation. It is concluded that the retention of small coal pillars is the optimal plan to reduce the impact risk of the working face along the goaf under extremely thick bedrock strata, and practice has been carried out. Precise erosion prevention measures such as long cutting holes, small coal pillar design, pre cracking of the basic roof along the goaf, pressure relief of solid coal along the goaf, high-strength basic support along the goaf, and advanced support have been implemented on site. The results show that the small coal pillar working face in Shilawusu Coal Mine has been realized, and the results can provide a reference for the gob-side mining of working faces under similar conditions.

Large trucks are an important component of the transportation system in open-pit coal mines. The effective utilization of trucks not only directly affects the progress of the project but also has a significant impact on the economy of open-pit mining enterprises. To effectively solve the truck failure prediction problem in open-pit mines, a BP neural network model based on an improved gray wolf optimizer is proposed to predict the number of truck failures and the duration of truck failures in open-pit mines. This method first addresses the shortcomings of the traditional gray wolf optimizer’s weak convergence performance and local escape extreme value performance by integrating Circle chaotic mapping, nonlinear update mechanism, and population update method based on linear interpolation to propose an improved gray wolf optimizer (IGWO) and verifies the effectiveness of the IGWO algorithm through comparison with 6 benchmark functions and 6 algorithms. Secondly, using the better optimization performance of the IGWO algorithm to find the optimal weights and thresholds in the BP neural network model, an IGWO-based BP neural network model (IGWO-BPNN) is proposed. Finally, taking the truck failure data of the Baorixile open-pit coal mine as an example, the effective prediction was performed using the IGWO-BPNN model. Experimental results demonstrate that, under identical experimental conditions, the IGWO-BPNN algorithm exhibits superior predictive performance when compared to traditional BP neural network models and BP neural network models based on traditional GWO. The resulting predictive outcomes not only facilitate the development of scientifically-informed preventive maintenance plans for open-pit mining enterprises but also provide a robust foundation for data-driven decision-making in the construction of intelligent open-pit mines.

Abstract:In order to solve the problem of the transition from the first mining area to the second mining area in Hequ open-pit mine,Three transition modes of mining area are proposed, namely, re trenching, retaining trench with gentle slope and sector turning. Based on the current mining situation of Hequ Open pit Mine, the advantages and disadvantages of the three connection modes of mining area are compared and analyzed, and the transition mode of retaining trench with gentle slope is finally determined, two methods of mining with full pressure and internal drainage and mining with full reserved ditch and internal drainage were adopted. Based on the comprehensive benefits of the two mining methods, and on the basis of comprehensively considering the requirements of the mining procedure in the second mining area of Hequ open-pit coal mine and the impact of ditch retention on the internal drainage transportation system, raw coal transportation system, and the change of transportation distance, this paper systematically reveals the comprehensive impact law of various ways of wall pressure and internal drainage on the stripping system, and seeks the best mining procedure of wall pressure and internal drainage in the total wall pressure and ditch retention internal drainage schemes, The secondary stripping and transportation costs of materials with different mining methods are calculated, and the total cost model is constructed. Through technical and economic comparison, It can be concluded that the transportation distance of stripped materials discharged inside the full pressure wall is small, and the inner drainage space can be completely released. Stripped materials do not need to be discharged outside, and can be completely discharged inside. The mining will lead to a large amount of secondary stripping of the western end wall that contacts the first mining area during the mining process of the second mining area. The economic benefit is poor, while the secondary stripping amount of the full ditch drainage mining is small, but due to the influence of the ditch, the inner drainage space cannot be completely released, The transfer cost of stripped materials is increased. Meanwhile, large area of land needs to be expropriated to discharge stripped materials, and the overall mining cost is high. Comprehensive comparison of the two mining methods shows that the full ditch drainage mining has better economic benefits, and is superior to the full pressure wall drainage mining.

Water abundance evaluation of drenching tunnel is the premise for mine support design. In order to evaluate roof water abundance under the condition of alkaline water drenching tunnel, six indexes, including roof loose circle, crack growth degree, temperature, humidity, pH value and water drenching time, were selected as main indexes to evaluate the water abundance of roof. AHP (Analytic Hierarchy Process) focuses on the subjective evaluation of experts and the entropy weight method focuses on objectivity of data. Synthesizing the characteristics of the above two methods, this paper proposes a weight calculation method of water abundance index by coupling the improved AHP and entropy weight method through the least square method. Based on the field geological data of 50 groups in 5305 transport channelling in Zhaolou Coal mine, the water abundance evaluation of the drenching roadway roof was carried out based on the improved AHP method and entropy weight method. And the support design for the high water abundance zone is carried out based on the evaluation results. The results show that: The support design for water drenching roof can effectively control the development of loose circle and the water drenching condition of the roof, which has a reference significance for the whole mine and the eastern coal mine with similar geological conditions.

To study the effect of loading rate on the macro-mesoscopic fracture characteristics of uniaxial compression of coal, uniaxial compression tests of coal samples at three loading rates of 0.06, 0.3 and 3 mm/min were carried out. Combined with acoustic emission and numerical calculation methods, the influence of loading rate on mechanical properties, acoustic emission characteristics, crack propagation and macroscopic failure modes of coal samples were analyzed. The results show that the higher the loading rate, the greater the uniaxial compressive strength and peak strain of the coal; The accumulated ringing counts and acoustic emission localization events keep decreasing with increasing loading rate; the microscopic fracture damage transitions from tension damage to shear damage; the macroscopic damage mode changes from a small amount mixed tensile-shear microcrack damage at low loading rate to a single penetrating shear crack damage at high loading rate; the numerical simulation results effectively support the indoor test conclusions and reveal that the damage of coal samples is essentially the destabilization of the force chain system. It sees that the increase of axial stress before the peak stress makes the local force chain strength difference increase, and the fracture of the strong and weak force chains produces the macroscopic damage of the coal.

The traditional coal mill liner will unavoidably wear and deform over time. It causes significant changes in the movement law of the grinding medium in the cavity and significantly lowers the efficiency of coal breaking. In this study, the ?4.04 × 5.54 m coal mill in a thermal power plant was taken for research, and the evolution process of the grinding medium movement before and after the wear of different cavity liners was explored. The flow state of the grinding medium, the collision relationship, the coal breaking efficiency, and the impact energy of the liner were modified and optimized. At the same time, the method of adjusting the mill barrel speed to promote the efficient coal breaking of the worn liner was used. The research investigates the variation in barrel speed effect on the law of medium flow. The results show that the coal breaking efficiency of the improved liner cavity is increased by 21.7 %, and the service life of the liner is prolonged. It is feasible to increase the cylinder speed to compensate the low coal breaking rate caused by the wear of the liner. The maximum coal breaking rate could be increased by 98.6%. And the normal and tangential cumulative contact energy of the liner might be increased by 144.9% and 54.9%, respectively, which accelerates the consumption of worn liners. The study provides theoretical guidance for improving coal utilization and production efficiency.

In-situ modified mining technology is one of the major directions of future mining technology development. In this paper, we combined coal supercritical water treatment technology and in-situ modified mining technology to study the percolation and deformation characteristics of anthracite coal of Φ25mm×50mm in the Sihe Mine under triaxial stress supercritical water environment. The results show that under the subcritical and supercritical water injection conditions of 365℃, 400℃ and 435℃, the permeability of anthracite coal decreases by 56.75%, 96.93% and 94.99%, respectively, compared with the original coal, and the overall permeability changes in the trend of rapid decrease and then slightly increase; the percolation channels of anthracite coal in the early stage of the experiment will gradually close, and after a period of continuous heat injection, the percolation phenomenon will The recovery time is about 43.5h, 24.54h and 19.81h; the recovery is accompanied by a sharp axial compression deformation, and the higher the test temperature is, the larger the axial compression deformation is, about 0.06, 0.11 and 0.16.

Because of the non-uniformity of raw coal gasification itself , fluctuations are inevitable in the operation of dry powder gasifier, which in turn have a large impact on the indicators of stable gasifier operation. In this paper, based on a dry pulverized gasifier of a plant, the controlled rate and key process parameters affecting the pressurized gasification process stability of pulverized coal are selected to conduct statistical process control analysis of the gasification process of the dry pulverized gasifier, and quantitatively assess the stability of the operation of Shenyou 3 coal in four dry pulverized gasifiers. The study shows that the controlled rate of all parameters is above 95%, and the overall operational stability of the four dry powder gasifiers is good. In order to further improve the stability of gasification operation, it is suggested to adjust the control range of gasifier pressure and effective gas content, improve the analysis and measurement accuracy of pulverized coal flow and methane content, and optimize the structure of gasifier. The statistical process control analysis method can well find some key process parameters fluctuation in gasification process of the dry powder gasifier, thus playing a better guiding role in the production process of the dry powder gasifier.

a large number of coal mines in Henan Province have been closed / abandoned due to resource exhaustion, illegal mining, improper operation and the national capacity reduction policy, forming a large number of underground spaces such as shaft, roadway, chamber and goaf, which provide basic conditions for the rational development and utilization of urban underground space. Based on the coal mine statistical data, ground data and underground survey data of Henan Province, this paper estimates the available underground space of coal mine roadway and goaf in Henan Province by using the proportional coefficient method and goaf model calculation method. The available underground space of roadway and goaf is 52.659 7 million cubic meter, and the available underground space of goaf is 180.255 21 million cubic meter, which is mainly distributed in the central and western cities of the province. Suggestions on comprehensive development and utilization of Zhengzhou, Pingdingshan, Sanmenxia, Hebi and Luoyang, which are typical coal mining cities with space resources of more than 10 000 cubic meter, are put forward.

In order to improve and perfect the management system of science and technology project funds of coal enterprises, improve the utilization efficiency of scientific research funds, promote the output of major scientific and technological achievements, and enhance the scientific and technological innovation ability of enterprises. Select the budget and final accounting data of the science and technology projects of S coal enterprise from 2012 to 2022, and adopt descriptive statistics and interval distribution methods to analyze the overall characteristics, structural characteristics and causes of the differences in the budget and final accounts of the projects. This paper puts forward effective and feasible optimization strategies of science and technology project fund management in coal enterprises from four aspects: budget preparation, review, implementation and supervision, and final account management, in order to provide reference for the fine management transformation of science and technology project fund budget and final account of coal enterprises.

An intelligent non-destructive inspection system of wire rope core conveyor belt is designed through the research of perspective and laser three-dimensional reconstruction technology, the failure characteristic detection and early warning of the inner and outer parts of the steel cord conveyor belt, the calculation of the frame selection area and the wear volume of the outer wear area, and the failure characteristic diagnosis of the steel cord such as the broken wire, tap, twist and the change of the length of the joint are verified by experiments, the results show that the system can accurately judge the fault point of the steel cord conveyor belt and give an early warning based on the analysis of the digital detection data of the belt.

To improve the rock-breaking performance of the hob in the process of hard rock roadway excavation, an experimental study on the influence of the cutting speed of the TBM hob on the rock-breaking performance under the action of prefabricated slits was carried out. In order to eliminate the uncertainty of the results caused by the non-uniformity of the slit depth distribution, on the basis of replacing the abrasive jet cutting process with the prefabricated regular slit, combined with the hob cutting load, specific energy and temperature indicators, the influence of the slit depth and its relative lateral distance to the hob on the rock breaking performance was studied from multiple dimensions. Additionally, the influence of the cutting speed on the cutting load and temperature of the TBM hob was analyzed, and the interaction relationship between the cutting speed, the depth of the cutting gap, and its relative lateral distance to the TBM hob was explored. Finnaly, the adjustment direction of the slotting parameters during the matching installation of the hob with a larger radius is obtained. The results show that when the cutting speed increases from 1.0 m/min to 3.0 m/min, the hob load increases by 15.04%, 43.83%, 89.79% and 161.84% respectively, and the maximum temperature of the hob increases by 30.01%, 87.51%, 121.26% and 134.55% respectively. The recommended cutting speed optimization range is 1.0~1.5 m/min. If the rock breaking efficiency of the hob needs to be considered at the same time, the cutting speed can also be relaxed to 2.0 m/min, but the cutting specific energy of the hob will be increased by 19.51%.