The frame support carrier is a kind of transportation equipment for long-distance transportation of hydraulic supports in fully mechanized coal mining face. Its unique U-shaped frame structure can realize the whole continuous transportation of hydraulic supports in fully mechanized coal mining face without disassembly. It has the characteristics of large load capacity, flexibility, safety and efficiency, and is the core equipment for moving and reversing faces in high-yield and high-efficiency mines. The frame support truck used in the early stage of China's mines is mainly imported, which inevitably has some defects, such as high cost of equipment and spare parts, untimely arrival and lagging technical support, which seriously affects the production efficiency of coal mines. With the continuous accumulation of technical research and application experience of imported equipment, combined with the moving and reversing technology of fully mechanized coal mining face in China, many key technologies, such as high-power explosion-proof diesel engine technology, wheel reducer technology with wet brake, sprocket+ring chain open load lifting technology, mining heavy-duty solid tire pressure release technology, etc., have been tackled with difficulties, adaptability improvement and independent innovation, realizing zero barriers of related technologies, and some technologies are already in place. After more than ten years' development, the series models of the frame support truck in China have achieved full coverage of the 30-100t load range, advanced technology and stable performance, which fully meet the use requirements of coal production enterprises in China. With the shift of national coal mining strategy and the advancement of battery power technology, the future frame support truck equipment will have greater development in thin coal seam and pure electric direction.

In order to study the feasibility of mining collapse column in Hequ open pit mine, the formation causes and strata occurrence of collapse column are analyzed in detail; Numerical simulation software is used to analyze the stability of the north slope, south slope and west slope of the collapse column, and the reasonable slope angle of each slope is given; Based on the basic principle of open-pit mining, the economic and reasonable stripping ratio of Hequ open-pit mine is calculated, and the collapse column mining scheme is further proposed and optimized. The research results show that the reasonable slope angles of the north, South and west slopes of the collapse column are 41 °, 43 ° and 30 ° respectively, and the economic and reasonable stripping ratio of Hequ open-pit mine is 6.2m3/t. The proposed collapse column resources are fully exploited, partially exploited and without mining. The stripping ratio of the three schemes are 2.51m3/t, 2.37m3/t and 4.02m3/t respectively. Are less than the economic and reasonable stripping ratio. Therefore, the resources inside the collapse column are economically recoverable, and the economic benefit of all resources mining scheme is the best.

Aiming at the problem of the width of narrow coal pillar and the stability of surrounding rock in gob-side entry driving with composite roof, taking the specific geological conditions of a mine as the engineering background, the stability of narrow coal pillar in gob-side entry driving with fully mechanized top-coal caving was studied by field investigation, theoretical analysis and numerical simulation. By studying and analyzing the distribution characteristics of the stress and plastic zone of the surrounding rock of the ‘ T ’ type coal pillar in the gob-side entry driving of the traditional fully mechanized caving face under the conditions of different narrow coal pillar sizes, the study shows that the plastic zone of the surrounding rock of the two sides of the gob-side entry driving of the ‘ T ’ type narrow coal pillar in the traditional fully mechanized caving face is asymmetric distribution, the failure depth of the roof composite rock is wide, and the narrow coal pillar is in an unbalanced bearing state, the width-height ratio is small, the stability of itself is poor, and the bearing capacity is poor. Based on the above problems, the staggered-layer staggered gob-side entry driving technology is proposed, and the numerical simulation research is carried out on the special-shaped coal pillars with different sizes. The results show that compared with the conventional ‘ T ’ narrow coal pillar, it has superior roadway protection effect of ‘ plugging air, preventing deformation and bearing capacity ’, which provides favorable conditions for the control technology of roadway surrounding rock.

Abstract: Based on the analysis of the auxiliary transportation conditions, the auxiliary transportation modes and main technical parameters were put forward for Xizhuo mine，a typical mine soft coal seam in Weibei. According to the present situation of mine construction, the technical advantages and disadvantages of the auxiliary transport mode were analyzed and demonstrated, and then the construction investment and operation cost were estimated and compared. After that, the monorail crane was determined as the auxiliary transport mode of mine.On this basis, through the calculation of operational parameters, monorail crane vehicles and track system were designed and selected. According to the layout of the roadway in the panel area, the location and design parameters of the monorail hanging chamber were determined.

In view of the high content of fine slime, the easy slime of raw coal, and the industrial site restrictions during the actual coal preparation process of the Buerdong coal mine, various recovery processes and layout forms of fine slime in coal preparation plant are compared. The results showed that the adoption of the filter press recycling process, and the integrated layout of pressure filtration workshop and coal slime drying yard for the fine slime is conducive to the recovery and treatment of fine slime in the plant, improving the competitive power of the fine coal products in the plant. Moreover, it can also provide a reference for the process layout of fine slime recovery in this area.

The intelligent integrated fire-fighting pump station is a combination of the assembled composite SW water tank and the intelligent fire-fighting pump house.The equipment can be produced modularly, the product quality is stable, the installation is quick, the construction period is short. The equipment has the characteristics of integration, standardization and intelligentization, which improves the public fire safety level and the safety reliability of fire water supply system.This paper discusses the design of outdoor fire pump station in coal mine life supporting area.. This paper introduces the selection of fire pump station type according to the reconstruction project construction conditions, and expounds the diversity and feasibility of the selection of fire pump station and pool type.

High level directional long drilling in coal seam roof is an important technical means of pressure relief gas drainage in coal face. Aiming at the technical problem of directional drilling of high-level hole in complex coal seam roof, a composite strong slag discharge directional drilling technology is proposed, a strong slag removal directional BHA with mud pulse while drilling measurement system and triangular spiral drill pipe as the core is designed, the principle of strong slag removal technology of triangular spiral drill pipe is analyzed, a complete set of composite strong slag discharge directional drilling equipment has been formed. The application research was carried out in 3314 coal face of Wangpo coal mine of Shanxi Tiandi Wangpo Coal Industry Co., Ltd. The results show that in the complex roof strata represented by mudstone, 6 high-level directional boreholes have been completed, the hole forming rate is 100%, the maximum drilling depth is 500m, the daily average footage is more than 70m, and the cumulative drilling footage is 2325m. The drilling efficiency and hole forming rate are greatly improved compared with the conventional directional drilling process. It provides a technical guarantee for the use of high-level directional long drilling in the roof instead of high drainage roadway to control the gas drainage in the working face and goaf, and support the safe and efficient production of the coal face.

In order to solve the problem of soft formwork concrete gob-side entry retention technology in stratified mining of extra thick coal seam, the design and application of gob-side entry retention in stratified mining of extra thick coal seam are studied and applied in a coal mine at 0102402 working face. Two small coal pillar reinforcement schemes are proposed, and the gob-side entry retention design scheme of double flexible formwork wall in stratified mining of extra thick coal seam is put forward for the first time.The application results show that: The roof and floor shape variables of the on-site roadway are reduced, the side roof of the goaf of the roadway is better, the steel beam shape variable of the roof is small, and the overall effect of roadway retention is good, but there are still some roadways with different degrees of floor heave phenomenon. With the continuous advance of the working face, the lagging working face of the entry retaining roadway is basically stable. Meanwhile, with the gradual familiarity and improvement of the construction technology of the workers, as well as the improvement and optimization of the entry retaining problems in the previous several stages, the design and application effect of the double-flexible die wall along the gob entry retaining in the stratified mining of extra-thick coal seam is good. This research is of great significance to the goaf retaining technology of thick and extra-thick coal seams.

According to the geological structure characteristics of Zhaozhuang 3# coal seam in the southeast of Qinshui Basin，in order to solve the problems of high-speed horizontal drilling of CBM horizontal well along the near roof of broken and soft coal seam，safe landing of deflecting section，well trajectory control in horizontal section，anti collapse of coal seam shaft wall and solid completion，etc. Through theoretical analysis and practical experience，a complete set of technical system has been formed based on the structural design of the second spud in CBM horizontal well，accurate landing without pilot hole，accurate control of well trajectory，drilling fluid optimization and staged collar cementing. Through the actual drilling verification，many problems of CBM horizontal well drilling along broken soft coal seam are effectively solved，the construction cycle is shortened and the operation risk is reduced. The research results provide technical guidance for the drilling of horizontal wells of coalbed methane near the roof in broken soft coal seam，and have reference significance for the efficient development of coalbed methane in this area.

Aiming at the problem of acutely mining pressure in the condition of passing in and out the coal pillar under gully topography when fully mechanized caving in the lower part of the close coal seam group. Numerical simulation method is used to analyze the distribution law of the concentrated stress in the remained upper 9# coal pillar with the engineering background of the 9# and 10# coal seams in Shangyuquan coal mine. The superposition effect caused by the mining stress and concentration stress in coal pillar during the entry and exit of fully mechanized caving face in the lower 10# coal seam is explored. Combined with the roof structure model, it is clear that the instability mode of roof structure are rotary instability with slide instability, rotary angle and rock fracture degree are the key influencing factors of instability. Hydraulic support extrusion disaster prevention measures like driving technology lane under coal pillar and reducing mining thickness in view of the roof plate failure mode are promoted. Providing reference for roof control and disaster prevention in gully topography short-distance coal mining.

In view of the low oxygen problem in the return air corner of 22104 working face in Shangwan coal mine, the source and emission reason of low oxygen gas are studied, and the influence law of surface atmospheric pressure and temperature change on gas emission in goaf is analyzed. The results show that the low oxygen in the working face of 22104 is caused by the high nitrogen content in the CO2-N2 zone of the coal seam, and the oxygen consumption by oxidation of the left coal, resulting in a large amount of nitrogen in the goaf. Under the influence of mining, the surface fissure is easy to form an air leakage channel with the goaf, making the low oxygen gas in the goaf migrate to the return air side of the working face, resulting in abnormal gas concentration at the return air corner. Based on the analysis of the causes of low oxygen, the pressure difference between the working face and the goaf is balanced by the pressure equalization ventilation technology, so as to reduce the air leakage and low oxygen gas emission from the goaf to the working face, keep the oxygen concentration in the working face at a normal level, provide technical guidance for the treatment of low oxygen at the return air corner of the working face, and realize the safe and efficient production of the mine.

In order to avoid the roof water disaster caused by water and sand burst in the working face of the Western high-intensity mining area, this paper takes the first working face of caojiatan mine in Yushen mining area with fragile surface ecology as an example, analyzes the main control factors affecting the roof water disaster, and puts forward the water prevention countermeasures. The combination of physical detection and "three Diagrams" method is adopted to comprehensively demonstrate and analyze the water abundance characteristics of coal roof in the first mining face. The results show that the precipitation and surface water are the indirect water source of the mine, and the water from the aquifer of Yan 'an Formation, Zhiluo Formation and bedrock weathering zone in the affected area of the water-conducting fracture zone of coal seam roof is the direct water source. The water-conducting fracture zone is the main water-filling channel of mine water disaster. Mine weathered bedrock aquifer is rich in water and Yan 'an Formation is weak aquifer. FLAC 3D was used to study the motion and failure law of overburden fractures. When the working face advanced to 180m, the development speed of water-conducting fracture zone increased, and reached the maximum of 159m after the working face advanced to 240m, and the split-mining ratio of overburden was 26.5. Based on the sixteen character principle of water prevention and control, combined with the characteristics of water rich zoning of mine roof and the law of fracture development, the paper puts forward the water prevention and control technical measures of improving mine water disaster monitoring system and constructing waterproof and drainage system, reasonably determining mining parameters and training water prevention and control professionals, so as to jointly solve and prevent the occurrence of mine water disaster accidents. The research results of this paper have important theoretical and technical reference significance for the prevention of roof water disaster in the Western high-intensity mining area.

The inner section of 21109 main transportation roadway is excavated in solid coal，the geological conditions are simple，the time span from excavation to mining is short. therefore，the test conditions for advanced support technology without hydraulic prop are available. the industrial test is guaranteed by means of suspension theoretical calculation，on-site drawing force detection and strengthening construction quality management；technical means such as roof separation and surrounding rock deformation monitoring，borehole crack peeping and so on are adopted to test the implementation effect. the practice shows that under specific conditions，the support technology strengthened by ordinary anchor cable beam before mining can completely replace the advanced support technology such as single pillar and advanced hydraulic support；its bearing capacity can effectively resist the mining influence during initial mining，the safety of roadway roof has been guaranteed，the working space has been greatly liberated and the coal mining operation process has been significantly optimized.

In order to study the failure degree and characteristics of coal seam roof in coal mining, the direct roof and indirect roof are simplified to a stacked beam model with horizontal and vertical joints, and the stress potential function in elasticity is introduced to analyze the size and shape of the failure region of coal seam roof combined with Mohr-Coulomb strength criterion, which is further verified by 3DEC software. The results show that the failure of coal seam roof can be divided into separation caused by horizontal joints and faults caused by vertical joints, the failure domain of separated layer is "quasi-hyperbola" distribution with steep upper and lower plane, and the fracture failure domain is arched distribution. With the increase of the elastic modulus of the indirect top, the width and height of the separation layer of the direct roof decrease obviously, and with the increase of the height of the indirect top layer, the fracture height ratio of the indirect top decreases gradually, and the width of the separation layer increases gradually. This shows that when the layer height is determined, the stress of the coal seam roof is transferred to the hard rock, resulting in a larger area of failure area; when the lithology is determined, the larger indirect top height can significantly reduce the fault height and increase the separation failure width. This study can provide relevant theoretical basis for practical engineering problems in the field of coal seam roof failure.

Abstract:In view of this situation that there are many types of potential roof pressure relief technical solutions, but under most conditions, qualitative methods are used to optimize among many alternatives,In this paper, the technical solutions selecting of the top-cutting roof pressure relief for 6105 working face of Yuan Bao Wan Coal Mine is taken as an example,by the method of hierarchical analysis which can achieve quantitative selection determining the top-cutting roof pressure relief measure.This method comprehensively analyzes the influence weight of each factor on the top-cutting pressure relief plan, avoiding the one-sided expansion of the influence weight of a certain factor, and displaying all the influence weights of each factor on the final plan in a quantitative form, the conclusion is more logical and scientific , having a strong guiding significance and reference value for the selection and optimization of the top-cutting pressure relief technology program with any other options which have many options to choose from.The results of the hierarchical analysis method show that the weight of the directional hydraulic fracturing top-cutting pressure relief scheme is higher than that of the blasting top-cutting pressure relief scheme aimed at the roof of 4# coal room pillar goaf overlying 6105 working face ,good results have also been achieved through practice.

In order to solve the problem of large deformation and serious damage of broken surrounding rock roadway under the top coal failure area, taking the auxiliary transportation roadway of 32103 working face of hanzui mine as the research object, the stress distribution and deformation mechanism of roadway surrounding rock are studied by combining field measurement and theoretical analysis. The results show that the top coal failure area in the roof of 32103 auxiliary transportation roadway is discontinuous distribution. The adjustment of surrounding rock stress environment of 32103 auxiliary transportation roadway and the reduction of effective bearing width of top coal pillar and section pillar are the main reasons for the obvious ground pressure behavior of roadway. Based on the above detection and theoretical analysis results, the roadway surrounding rock control technology based on "deep and shallow hole grouting + anchor mesh cable" combined support and the reinforcement technology based on "shed + floor pressure relief" are proposed. The field application results show that after the new support scheme is adopted, the maximum roof and floor displacement of surrounding rock in 32103 auxiliary transportation roadway is 70mm, the maximum convergence of two sides is 48mm, the supporting bolt is not broken, and the bolt stress and surrounding rock deformation are in a reasonable range, and the roadway support effect is good.

Taking 13121 upper working face of Gubeimine as the research background, through theoretical analysis of the initial and periodic breaking steps of thick and hard straight roof, the roof pre-splitting cutting scheme is proposed, and FLAC3D software is used to verify the cutting effect of thick and hard roof. The displacement law of thick and hard roof and the variation characteristics of advance supporting stress of working face before and after cutting roof are coMPared. The results show: Pre-splitting the top can effectively improve the working environment of the straight overlying hard thick roof. After cutting the top, the peak value of the advance supporting stress of the working face is reduced by 28.39%, the influence range of the advance is reduced by 37%, the step distance of roof collapse and coMPaction is shortened by 43.53%, and the position of the peak value of the advance supporting stress shifts to the deep. The pre-split cutting roof plays a positive role in themine pressure control of the straight overlaying working face with thick and hard roof, which has reference significance for the design of advanced support of working face.

Aiming at the problem that there was no unified certification standard for high-end hydraulic support in China, and it was impossible to make a scientific and reasonable evaluation on the design, manufacturing and certification of high-end hydraulic support, this paper discussed the establishment of high-end hydraulic support product certification and evaluation mode that suitable for the development of coal mine intelligence in China by analyzing the development status of coal mine intelligence and the differences in the detection and certification of high-end hydraulic support at home and abroad.?The research showed that the certification of high-end hydraulic support not only considered the hydraulic support as a single body, but also closely combined with the needs of intelligence;?The certification adopted the "voluntary certification" mode, including "manufacturer application+expert review+technical review+inspection scheme formulation+product inspection+supervision after certification";?The certification standard adopted personalized and customized methods to increase the whole cycle control and complete set quality monitoring of products;?Quantitative indicators and detection items related to intelligent requirements were added to the whole machine test.

Abstract:In view of the problems of excessive mixing and excessive drilling in the on-site anchor bolt construction of coal mine, the anchoring force is tested through the pull-out test, and the splitting device is cut open to observe the anchoring state. Taking the anchoring force and anchoring state as the measurement index of anchoring quality, the comparison test is carried out on the two on-site design and construction factors of mixing time and annular thickness affecting the anchoring quality of anchoring agent, The influence of two factors on anchorage quality is analyzed, and some suggestions for on-site construction are put forward. The results show that when the medium speed anchoring agent is used and the length of the anchoring section is 125mm, the anchoring agent can be fully stirred in a short time to obtain the ideal anchoring quality; When the annular thickness of the anchoring agent is 2 ~ 3mm, the anchoring quality is good and stable. With the increase of the annular thickness of the anchoring agent, the drawing force decreases obviously and the anchoring quality fluctuates greatly.

Highly-mineralized mine water discharge influenced the ecological?environment around?the?coal mine?area, based on the current situation of highly-mineralized mine water treatment and utilization technology, the?coal mine?area chose highly-mineralized mine water after advanced treatment was recycled on the production process and was back-filled underground coal to realize zero discharge of highly-mineralized mine water. Based on the groundwater quality of the coal mine and class III water quality requirements in Standard for Groundwater Quality (GB/T14848-2017), the paper proposed index of back-filling water quality to guide the selection of advanced treatment process, promoted the transformation of coal mines into green mines and green production modes, and provided reference for other similar coal mines.

Based on the study of the research status and development direction of unmanned driving technology applied in mine transportation field, the transportation safety risks of open pit mines were analyzed.The unmanned driving technology was divided into wire control technology, environment sensing technology, positioning and navigation technology, path planning technology, and decision control technology according to the specific functions, and the advantages and disadvantages of each key technology implementation method were analyzed. Based on the study above and the analysis on each key technology, it was concluded that multi-technology integration to realize environment sensing, positioning navigation, path planning and decision-making control is the inevitable trend of the development of unmanned driving technology in mines.

Due to the similar density of organic macerals in coal, how to effectively separate vitrinite from inertinite has always been a difficult problem in coal processing. Low density heavy medium cyclone is a feasible method to separate vitrinite from inertinite, but because of low density and small solid volume concentration in the system, the suspension is easy to settle and worsen the separation effect. In this paper, the stability and rheological properties of dense medium suspension mixed with fine magnetite powder, low ash slime and montmorillonite powder are discussed. The results show that under the condition of a certain suspension density, the addition of slime can effectively improve its stability in the gravity field, while nearly adding montmorillonite cannot increase the trend of delaying settlement. Due to the synergistic action of magnetite powder, montmorillonite and low ash slime, the heavy medium suspension could form remarkable structure and obtain the best stability. In addition, the heavy medium suspension shows pseudoplasticity in accordance with the power law. The apparent viscosity of the heavy medium suspension mixed with magnetite powder, montmorillonite and low ash coal slime could be as low as about 70 mPa·s at shearing rate of 70.22s-1, and even could theoretically reach as low as 35 mPa·s at shearing rate of 200 s-1, which is more in line with the requirements of low viscosity and good stability of suspension during heavy medium cyclone separation. It means that moderately increasing the ash content of coal slime in heavy medium suspension will be beneficial to the stability of separation.

Hydraulic fracturing is an effective technical means for the prevention and control of coal rock dynamic disasters such as rock burst, coal and gas outburst in coal mines. Hydraulic fracturing of coal and rock mass can induce a large number of weak microseismic signals. Aiming at the problems of microseismic signal identification and fracture location monitoring of hydraulic fracturing of coal and rock mass, the overall architecture of microseismic monitoring software for hydraulic fracturing of coal and rock mass was proposed. The microseismic monitoring software system for hydraulic fracturing of coal and rock mass in coal mine was designed and developed by using python language and Visual Studio Code editor. Based on engineering practice requirements, the software adopts modular design concept, including project management, parameter configuration, data call, data analysis and processing, three-dimensional visualization, event preservation and export function modules. The software interface is simple and easy to operate, which realizes the accurate identification of weak microseismic signals induced by hydraulic fracturing in coal and rock mass, the source location and source mechanism analysis of hydraulic fracturing. The spatial coordinates and source mechanism of hydraulic fracturing microseismic location events are visualized in three-dimensional, so as to dynamically depict the propagation process and spatial morphology of hydraulic fracturing in coal and rock mass. The research results provide effective technical means for the monitoring of hydraulic fracturing of coal and rock mass in coal mines, which is of great significance for the optimization design of hydraulic fracturing in the field.

Multi-layer combined pressure is a key technology to improve multiple types of gas-bearing gas layers. However, due to the large difference between coal lithology and sandstone and shale, fracture propagation is more complicated than single-layer fracturing, especially the existence of coal seams makes the change of fracture shape unpredictable, which brings technical difficulties to fracturing design and implementation. For this reason, through indoor experiments to measure the peostress of coal seam roof and floor, establish multi-layer finite element inversion model, carry out in-situ stress inversion calculation of coal seam, and the feasibility of the combined pressure of different types of formations is analyzed. The results show that the error of the inversion calculation result is less than 5%, and the credibility is high; the conditions of the multi-layer combined pressure penetration layer are: the fracture is a vertical fracture, the fracture pressure difference is small (<5MPa), and the combined pressure layer difference is less than 18-20m; When multiple reservoirs are combined, the upper reservoir is in better condition, try to avoid pressing the lower coal seam; when the lower coal seam cracks, the proppant mainly supports the lower coal seam, and for the upper strata, the supporting effect is relatively poor.Cracks from the coal seam can take advantage of the stress shielding effect to increase the length of the seam in the coal seam when the coal seam is in the upper part, and the sandstone gas layer is in the lower part. The research results can provide guidance for the calculation of the stress of each layer, the judgment basis and conditions of the combined pressure, and the selection of the crack initiation layer when the multi-layer combined pressure is calculated.

Qinshui Basin is the main CBM basin in China, and its deep coalbed methane has become the main object of CBM development in the future., In view of the insufficient understanding of deep CBM reservoir of the basin and the lack of targeted measures for development ,taking Shouyang block in the north of Qinshui Basin as the research area and coal 15 as the research object, the geological particularity and development countermeasures of deep CBM are discussed. Coal seam 15 is basically stable, the thickness is basically about 3m, and the thickness scale is controlled by sedimentary environment and sedimentary facies. Most of the gas content is between 10 ~ 12 m3/t, and it is affected by the buried depth and the degree of metamorphism. After the critical point appears at the buried depth of about 1200~1500m, the gas content gradually decreases with the increase of depth. Different from the "three high" characteristics in other deep areas, the deep reservoir of coal seam 15 is characterized by low pressure, high stress and medium temperature, which belongs to the category of serious low pressure gradient and geothermal gradient. The permeability is classified as high porosity and low permeability, and the permeability is generally 0.01 ~ 0.1mD. The permeability is mainly affected by the buried depth of coal seam, in-situ stress, coal structure and coal pore characteristics. According to the low moisture content, high porosity and gas production characteristics of production wells of coal seam 15, it is considered that coal seam 15 may have a high proportion of free gas content. Based on the geological particularity of CBM and the current situation of development technology at home and abroad, the countermeasures and suggestions for CBM development mode and key processes are put forward, that is, the segmented fracturing mode of horizontal well in roof rock stratum or the method of multi branch horizontal wells in surrounding rock can be used when developing coal seam 15 alone, which has made a breakthrough in gas production at 15 coal in the southern basin.The vertical well mode of surrounding rock and coal seam combined pressure can be used when developing multi coal seams, the corresponding suggestions on increasing production and drainage technology are put forward.

Vibrating Flip-flow screen is an effective means to solve the problem of viscous and wet fine particle screening, and its dynamic structure has an impact on the stability of vibration response and screening effect. In order to study the dynamic structural characteristics of the vibrating relaxation screen, this paper takes the 0827 circular vibrating relaxation screen as the research object. Firstly, the rigid-flexible coupling model of the vibrating Flip-flow screen is established.The finite element method is used to calculate the prestressed modal of the screen, and the first eleven-order modal parameters are obtained. According to the calculated modal parameters, the sampling frequency setting and other factors in the experimental test are determined, and then the force hammer method is used for the experiment to obtain the experimental modal parameters of the screen.The results show that the working frequency of the vibrating Flip-flow screen is reasonable. The comparison of the two modal analysis results proves that the theoretical analysis and the experimental analysis are basically the same, indicating the rationality and reliability of the finite element method. This research provides a basis for the analysis and optimization of large-scale vibrating relaxation screens using this kind of finite element method, and at the same time, structural improvement measures are proposed for the analysis results to improve the performance of the screen.

HA-Cd stability is the key to the effectiveness of humic acid adsorbents in treating cadmium-contaminated wastewater or soil. There is a risk of release of Cd2+ from HA-Cd in different pH environments. In this paper, pure water, pH=3 acetic acid, pH=5 or 7 acetic acid-sodium acetate buffer solutions were used as desorption agents to study the adsorption stability of coal-based HA-Cd. The results show that the functional group, humification and aromatization degree of coal humic acid are the main structural features that affect the stability of HA-Cd. HA1 has more active oxygen-containing functional groups than HA2, so adsorption capacity of Cd2+ is higher than HA2. At the initial concentration of Cd2+ is 100mg/L, Cd2+ adsorption capacity of HA1 and HA2 could reach 905mg/g and 582mg/g. Both HA1-Cd and HA2-Cd show excellent stability in pure water desorption. As the initial concentration of Cd2+ increases, the retention rate of Cd2+ decreases slightly, but overall more than 80%. After desorption of acetic acid solution with pH=3, the retention rate of Cd2+ decreases significantly. Due to the higher degree of humification and aromatization, HA2 has a larger degree of agglomeration in the adsorption process of high concentration Cd2+ solution, and the retention of Cd2+ is stronger. The desorption regularity of HA1-Cd and HA2-Cd is consistent with the increase of initial concentration of Cd2+ in desorption solution with pH=5 and 7. When the concentration of Cd2+ is higher, the retention rate after three desorption is higher, which is about 60%. Zeta potential analysis shows that there are two pathways of Cd2+ dissociation including spontaneous dissociation and ion exchange. The co-action of H+, Na+ and acetate ligand would lead to the re-release of the unstable Cd2+. This study clarified the desorption law of HA-Cd in different acidity environments and the influence of HA composition and properties on the retention characteristics of Cd2+, which provided a scientific basis for the effective treatment of cadmium pollution in wastewater or soil by coal humic acid and the prevention of secondary pollution caused by unstable adsorption.

Aiming at the problem of gas drainage boreholes and water accumulation in pipelines restricting the drainage efficiency in high gas and outburst coal mine, this paper developed a dual-channel continuous drainage and slag discharge device, and innovatively designed a solid-liquid separation filter plate and a gas-liquid separation screen. The upper and lower ends are respectively equipped with double-channel bypass pipes and double drains, which can realize continuous gas extraction and large-flow drainage in the process of water discharge and slag discharge. A multi-factor evaluation method was constructed based on indicators such as water discharge-slagging effect, operational performance and economic cost, and a comprehensive evaluation and optimization of three common water dischargers and this device were carried out. Excellent performance, convenient operation, wide application range, low manufacturing and maintenance costs, etc. Iit is applied in the 10102 working face of Hongyan Coal Mine, and the influence factor of discontinuous drainage is proposed as the evaluation index of water drainage method affecting drainage. There is a negative correlation. The reduction in the concentration of gas extracted within 20 days of using this device is only 61% of that of the traditional manual water discharger.

According to the drilling technology characteristics of directional horizontal grouting well and stratum characteristics of limestone layer, the characteristics of stratum to be drilled, drilling technology and conventional bit wear are studied, by analyzing the geological characteristics and structure of site, borehole design and well body structure. The bit profile shape, cutter arrangement, cutter mounting Angle and diamond composite were optimized. Parabolic profile, Limit density distribution of teeth and increasing reserve teeth for key parts to reduce the bit key parts wear and tear, improve bit offensive, and through the numerical simulation analysis of rock fragmentation efficiency of special-shaped cutter, and strengthen the cutting teeth of nose , improve bit impact toughness, prevent bit impact damage. The service life of the optimized bit is increased by 58.18% compared with conventional PDC bit in field test. The average speed of composite drilling is 50% higher than that of conventional PDC bit. The average speed of directional drilling is 56.52% higher than conventional PDC bit, which achieves the requirements of optimal and fast drilling for bottom grouting construction in limestone layer, and provides a bit design scheme for directional well drilling in hard rock fractured stratum, and provides technical support for the construction of grouting well in similar stratum.

In order to increase the coal loading rate of the spiral drum cutting coal and rock, the vibration impact technology is applied to the shearer cutting arm, and a lightweight vibration impact cutting arm with a double-row five-star hydraulic motor as the main driving device is designed using TRIZ theory. The discrete element method is used to analyze the single-factor numerical simulation experiment of the axial vibration frequency of the spiral drum to determine the horizontal range of this factor in the orthogonal experiment; the three factors of "drum speed, axial vibration frequency and working amplitude" are orthogonalized The test analysis shows that three factors affect the coal loading performance. The results show that the coal loading rate of the spiral drum shows a trend of decreasing with the increase of speed, and the coal loading rate of the optimal coal loading performance scheme is 54.56%. The research results provide a reference for the lightweight design of coal mining machinery and the improvement of the coal loading performance of the cutting arm.