Coal Engineering

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Research and Application of Pumping Pillar Supporting Large Section Abandoned Roadways Technology for Shendong MineArea

Coal Engineering 2022, 54 (10): 31-37. DOI: 10.11799/ce202210007

Abstract （278）

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In order to solve the safety problem of large section abandoned roadway in fully mechanized mining face, the research on abandoned roadway supporting technology at home and abroad was carried out. The technical problems caused by jump mining, filling and conventional reinforcement support were analyzed. The deformation and instability of surrounding rock and pumping support mechanism of abandoned roadways were analyzed.The treatment combining pumping support and anchor cable support was put forward. Through numerical simulation and theoretical calculation, the design of anchor cable &W steel belt &wall net & pumping pillar around goaf is determined. Wulanmulun colliery industrial test showed that, both working face and roadways floor heave didn’t occur during cutting through abandoned roadways. Within a total of 10 measuring points arranged, the maximum subsidence is less than 12cm. When pumping pillar has been cut more than 2/3 diameter, buckling collapse occurred. It shows that the pumping pillar has the characteristics of anti-dynamic load, large deformation, good stability and easy cutting, which can meet the needs of surrounding rock control of large section abandoned roadway.

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Energy Consumption Model of Gyratory Crusher Based on EDEM

Coal Engineering 2023, 55 (2): 152-157. DOI: 10.11799/ce202302027

Abstract （203）

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Gyratory crusher is the key coarse crushing equipment in the material crushing link, the bulk of the broken material is large, the motion state of the material in the crushing chamber is complex and changeable, especially the key working parameters have a great impact on energy consumption, domestic related enterprises lack the theoretical model of crushing energy consumption to guide the reduction of energy consumption in the design and manufacturing process. Based on the basic parameters of Metso 60-110E gyro crusher in Finland, this paper uses Solidworks to build a three-dimensional model. Based on the discrete element simulation software EDEM, it analyzes the influence of key parameters such as precession Angle, bottom Angle of moving cone, speed of moving cone, and size of ore outlet on energy consumption of the crusher, and establishes a theoretical prediction model of energy consumption of the crusher. The key parameters of the gyratory crusher are obtained. The results of response surface analysis and model variance analysis show that the precession Angle and cone speed have the most significant influence on the energy consumption model. When the same crushing force is obtained, the precession Angle is 0.48°, the bottom Angle of the moving cone is 79.99°, the rotating speed of the moving cone is 130.00 r /min, and the size of the ore outlet is 166.24mm, the performance of the gyratory crusher is optimal. Compared with the unit energy consumption of the gyratory crusher under the original working parameters, the energy consumption is reduced by about 1.9%. Finally, by comparing with the field data, the model is basically reliable. The model can provide reference for the design and energy consumption prediction of high performance gyratory crusher.

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Exploration on large-scale utilization mode of coal gangue in Shendong high-intensity mining

Coal Engineering 2023, 55 (4): 1-7. DOI: 10.11799/ce202304001

Abstract （418）

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In view of the large output of gangue in Shendong high-strength mining, and the limitations of existing gangue utilization and disposal methods, resulting in insufficient digestion capacity of gangue, a large-scale utilization mode of coal gangue in Shendong high-strength mining was proposed. The production and actual production conditions of coal gangue in Shendong mines, the actual situation of Shendong mining area and the distribution of surrounding industries, and the utilization ways of coal gangue in each mine were analyzed. The processing capacity, technical advantages and disadvantages of coal gangue utilization methods such as coal gangue power generation, coal gangue paving, coal gangue brick, sand and ceramsite, and coal gangue filling were summarized. The large-scale utilization mode of coal gangue in Shendong mining area was constructed. That is to give priority to the needs of local and surrounding industries to realize the resource utilization of part of coal gangue on the ground. Combined with the recovery coal pillar and disaster management of the mine, the gangue filling mining consumes most of the remaining gangue, and the application of filling mining shall not affect the mine yield. At the same time, the filling method is appropriately optimized, and the “ one mine, one policy ” is accurately implemented. The classification and precision filling mode of Shendong underground is formed, such as strip cemented paste filling, fully mechanized paste filling, grouting filling, solid filling, “ mining-concentration-filling ” integration filling and multi-mode comprehensive filling. This ' ground resource utilization + underground precise filling ' gangue large-scale utilization mode can maximize economic benefits and gangue disposal and disaster management benefits. The study can provide guidance for large-scale utilization of coal gangue in high strength mining area.

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Coal Engineering 2023, 55 (4): 77-81. DOI: 10.11799/ce202304014

Abstract （188）

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People oriented, concise and efficient -- a summary of the reconstruction and expansion of Wangwa coal mine

Coal Engineering 2023, 55 (4): 8-12. DOI: 10.11799/ce202304002

Abstract （348）

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The reconstruction and expansion of Wangwa coal mine is to expand to 6.0Mt/a on the basis of the original 1.50Mt/a design production capacity. The reconstruction and expansion follows the principle of people-oriented, simplicity and efficiency. By simplifying the ground layout, optimizing the development layout, underground parking lot deployment, mining area roadway layout and mechanical equipment, optimizing the underground streamline design and other measures, the goal of simplicity and efficiency of the mine system has been achieved, with less investment and short construction period. It has laid a good foundation for the intelligent construction of the mine and the construction of green mine. The design and construction of the project have positive reference significance for similar reconstruction and expansion mines.

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Study on starting stress condition discrimination and prevention measures of coal pillar rockburst

Coal Engineering 2023, 55 (5): 57-62. DOI: 10.11799/ce202305010

Abstract （163）

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

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Comprehensive Utilization of Coal Gasification Fine Slag and Car-bon Ash Separation Technology

Coal Engineering 2023, 55 (5): 175-182. DOI: 10.11799/ce202305030

Abstract （470）

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

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Research progress and prospects of rapid TBM excavation in coal mine rock roadways

Coal Engineering 2025, 57 (1): 1-7. DOI: 10.11799/ce202501001

Abstract （245）

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The classification and characteristics of the development stages of TBM in coal mine rock roadways in China have been analyzed; The application characteristics of TBM in coal mine rock roadways from 2015 to 2024 were summarized, including the main application provinces, rock roadway types, cutterhead diameters, and production groups; The current status of TBM excavation technology in coal mine rock roadways was analyzed from three aspects: advanced detection and prediction technology, adaptability technology to geological conditions in mine production, and stability control technology for roadway surrounding rock. Finally, prospects for future research on coal mine TBM were proposed from three aspects: stability control of deep rock roadway surrounding rock, advanced detection and excavation parameters, equipments adaptability, and rapid assembly technology. This has certain reference value for the design and application of coal mine TBM.

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Study on Carbon Emission Characteristics of the Whole Life Cycle of Underground Coal Mining

Coal Engineering 2023, 55 (1): 162-167. DOI: 10.11799/ce202301029

Abstract （249）

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This paper analyzes the carbon emission boundary and carbon emission sources in the whole life cycle of coal mining based on the life cycle approach and underground coal mining process, constructs a carbon emission accounting model for the whole life cycle of coal mining, and finally conducts an example study with the actual production situation of coal producer M. The results show that methane escape and electricity consumption are the most important factors of greenhouse gas emissions from coal mining; the basic electricity consumption to maintain the normal operation of the mine is the largest power consumption item in the whole life cycle of coal mining, and the digging and retrieval equipment also occupy a large proportion in the electricity consumption. Finally, the low carbon development countermeasures of coal production enterprises are proposed.

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Research on high-quality development ground space layout of Taigemiao mining area in Xinjie

Coal Engineering 2023, 55 (1): 1-5. DOI: 10.11799/ce202301001

Abstract （491）

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The traditional mining area is limited by many development subjects, and there are many problems in the surface spatial layout, such as resource waste, environmental pollution, imperfect layout, lack of unified whole life cycle planning and dynamic adjustment mechanism. In the layout planning of ground space, through scientific innovation, the concept of land space planning is introduced, and the relevant influencing factors are studied and analyzed, the spatial planning of mining area is combined with the layout of ground facilities organically, and the industrial site is centralized and planned by stages, which effectively solves the problems existing in the layout of traditional mining area, for the Xinjie Taigemiao Mining area to provide a blueprint for high-quality development.

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Research on the Implementation Path of High Quality Development in Xingjie Taigemiao Mining Area

Coal Engineering 2023, 55 (2): 1-6. DOI: 10.11799/ce202302001

Abstract （357）

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Under the background of new stage, new concept and new pattern, the high-quality development of mining area plays an important role in ensuring the safe supply of energy and promoting the transformation and upgrading of coal. Based on the existing research results of high-quality development of the coal industry, the connotation and characteristics of high-quality development of the mining area are proposed through summary and analysis, and the concept of high-quality development of the 16 word mining area is proposed, which is innovative, open, intensive, efficient, intelligent, safe, green and harmonious; This paper puts forward the general idea of the high-quality development planning of the Taigemiao mining area in Xinjie, and expounds the specific implementation path of the high-quality development planning of the Taigemiao mining area, which mainly includes the mining area development layout, intelligent security, green low-carbon, humanistic harmony, public services, transportation and logistics, innovation driven, management mode, etc．

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Study on characteristics and occurrence law of coal mine accidents in China from 2020 to 2021

Coal Engineering 2022, 54 (7): 129-133. DOI: 10.11799/ce202207023

Abstract （659）

PDF（mobile）（1487KB）（230）

Based on the statistics of coal mine safety production accidents in China from 2000 to 2021, the following accident characteristics are obtained: ① after 2002, the number of coal mine accidents and deaths in China decreased rapidly with an average annual rate of 18.4% and 17.6% respectively. ② The proportion of major accidents, major accidents and ordinary accidents is generally stable at 1:4:45, which shows that to effectively prevent major accidents, we must start from resolving ordinary accidents. ③ In recent five years, roof, transportation, other and gas accidents are still frequent, and gas, roof, water and fire accidents are easy to cause mass casualties. ④ Accidents occurred frequently in May, and major accidents occurred frequently in January, November and December. ⑤ Landslides in safety management of some key state-owned coal mines and violations of laws and regulations in township coal mines are still the main causes of group injuries.

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Research on Groove Side Wear and Inner Curve Optimization of Scraper Conveyor Based on DEM-MBD

Coal Engineering 2023, 55 (2): 171-176. DOI: 10.11799/ce202302030

Abstract （155）

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In view of the serious wear problem of the middle groove side of scraper conveyor at present, the DEM-MBD coupling model of scraper conveyor was used to simulate its transportation process. It is found that in the process of scraper conveyor from no load to full load, the concentrated area of pressure inside the groove side gradually transfers from the lower edge of the groove side to the upper edge of it. And at stable full load, the pressure range of the upper edge of the groove side is 9842~10890 Pa, significantly greater than the maximum pressure of the lower edge of 8742 Pa, which is consistent with the severe wear of the upper edge of the groove side; The force exerted by the scraper on the groove is concentrated on the upper edge of the groove side, and the force ranges from 23950 N to 160350 N, with an average value of 85509 N, which is 30.76 times of the mean force exerted by coal on the groove side, indicating that the wear of the upper edge of the groove side is mainly caused by the rigidly rigid body wear between the scraper and the groove. The curve of the inner side of the groove was optimized, and the results showed that the pressure on the inner side of the groove and the force of the scraper on the groove side were reduced by 19.34% and 42.51% respectively, which provides a basis for the optimization of the groove structure.

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A method for automatic extraction and dynamic analysis of real-time pressure data of fully mechanized mining hydraulic support

Coal Engineering 2023, 55 (3): 120-126. DOI: 10.11799/ce202303022

Abstract （125）

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Mine pressure prediction is the key and difficult point of coal roof disaster prevention. At present, the popularity of hydraulic support electro-hydraulic control system makes the pressure data can completely and quickly reflect the change of roof pressure. However, due to the large amount of data and many interference information, it is difficult to complete it only by manual analysis. In view of this situation, a method that can automatically extract the cycle cycle, predict and divide the pressure area of the support pressure data is designed. Firstly, according to the working characteristics of the hydraulic support, design rules, and extract the pressure data under normal working conditions as the cycle data. Then, through the clustering method, combined with the pressure data of each support, the significant pressure area is divided. Finally, the LSTM algorithm is used to predict and analyze the cycle pressure data. The feasibility of this method is proved by practice, which provides ideas for the study of mine pressure law and safe mining.

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Plastic design and analysis for a deep frozen wall considering shaft-flank displacement convergence

Coal Engineering 2023, 55 (3): 1-7. DOI: 10.11799/ce202303001

Abstract （346）

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Frozen-wall design is a success prerequisite for the freezing method, few literatures have reported, however, that side-wall displacement convergence affects frozen-wall thickness design. To consider the influence of side-wall displacement convergence, the Column-hole expansion theory was used to derive the complete formal solutions on stress and displacement for plastic frozen wall and elastoplastic unfrozen formations, and a calculation formula of frozen-wall thickness was established. An engineering case was studied by three methods, to verify the correctness of the established formulas. The effects of horizontal ground pressure, cohesion and internal friction angle of frozen soil, elastic modulus and Poisson's ratio, cohesion and internal friction angle of unfrozen soil on side-wall deformation and frozen-wall thickness were analyzed. The results show that the frozen-wall thickness difference is about 8.6% and side-wall deformation is about 0.17 at 800 m depth, considering the influence of well side displacement convergence or not, for the fully plastic frozen wall and elastic formation mechanical model. The new formula has high theoretical significance and practical value in predicting the side-wall deformation for a kilometer topsoil shaft.

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Mechanism of abnormal ground pressure and application of prevention technology during The working face passes through the coal pillars

Chuanjiu ZHANG

Coal Engineering 2022, 54 (9): 70-74. DOI: 10.11799/ce202209013

Abstract （228）

PDF（mobile）（1755KB）（13）

Abstract：Taking 42204 working face of bultai coal mine as the engineering background，using theoretical analysis and field test, the mechanism of abnormal ground pressure and application of prevention technology during the working face passes through the coal pillars are studyed. The results show that: The theoretical minimum mining height without instability of the roof of the overlying working face is 10.32m, Through theoretical calculation, the minimum collapse height required to fill the goaf is 31m, Combined with the occurrence characteristics of rock stratum, the reasonable fracturing horizon is calculated, The hydraulic fracturing scheme of "directional long drilling in working face + along slot shallow hole" is put forward. The results of ground pressure monitoring data show that the length of periodic pressure on the roof decreases, The goaf can be enriched by caving roof rock blocks, the maximum subsidence of the roof in the triangle area of the tail of the working face is 200mm, The maximum subsidence of the roof of the return air roadway is 80mm,The maximum approach of two sides is 150mm, The application results show that hydraulic fracturing can weaken the integrity of the roof, The ground pressure of working face in the area affected by coal pillar is reduced.

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Numerical simulation of stope stress evolution law of deep buried thick roof face and research on regional hydraulic fracturing and pressure relief technology

kaicai kaicaikaicai

Coal Engineering 2024, 56 (11): 110-117. DOI: 10.11799/ce202411017

Abstract （53）

PDF（mobile）（4321KB）（1）

Aiming at the problems of high stope stress, large deformation amount and large roof fracture energy of the working face under the condition of deep buried thick sandstone roof remining, the FLAC numerical simulation of the stress evolution law and stope displacement evolution law of the 130207 deeply buried high-stress stope is simulated, and the results show that when the working face is advanced to the primary square and the second square, there will be high stress concentration, the concentration coefficient can reach up to 2.5~4.0, and the horizontal displacement of the return air lane gang during the second square period can reach 390mm. The kick drum volume can reach 413mm. In order to ensure the safe recovery of the working face, a regional hydraulic fracturing and pressure relief scheme was formulated, and the key disaster-causing layer of the working face was calculated according to the key layer theory and composite beam theory 130207 the key disaster-causing layer of the working face was 22.83m thick coarse-grained sandstone layer and 40.23m thick coarse-grained sandstone layer, and the rupture pressure was 13.06MPa according to the calculation formula of Hubbert-Willsi non-permeable formation rupture pressure. After regional hydraulic fracturing, the working face cycle pressure step distance and the continuous pressure distance were significantly reduced, the influence range and stress concentration coefficient of the advanced supporting pressure were significantly reduced, and the daily maximum energy and daily average energy of the working face were significantly reduced, which indicated that the hydraulic fracturing technology in the directional area had good effect and had promotion and application value.

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A review of coal gangue identification methods based on optical images

Coal Engineering 2022, 54 (7): 159-163. DOI: 10.11799/ce202207028

Abstract （518）

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The coal gangue identification method based on optical image has the advantages of simple equipment, easy realization, greenness and environmental protection, and it is an important way to realize intelligent coal gangue separation.There are two research ways. One way requiresextracting artificial features for recognition, which generally includes four steps: coal and gangue image data set collection, image preprocessing, feature extraction and selection, and coal and gangue recognition. The other way uses deep learning neural network to independently extractfeatures.This paper summarizes the different methods in the two research ways, and points out that the existing identification methods have shortcomings such as incomplete coal gangue image data set, incomplete feature understanding, and failure to give consideration to both efficiency and real-time performance. Suggestions for efficient coal gangue identification are put forward.

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Effect of insulated inner tube on performance of coaxial heat exchanger in medium-deep geothermal well

Coal Engineering 2023, 55 (2): 164-170. DOI: 10.11799/ce202302029

Abstract （149）

PDF（mobile）（2059KB）（31）

Abstract: As an important component of the underground heat exchange system, the performance of the coaxial heat exchanger in medium-deep geothermal wells directly determines the efficiency of geothermal energy development and heat extraction effect. In this paper, the relationship between the heat-insulating inner tube and the heat transfer performance of coaxial heat exchanger in medium-deep geothermal wells is investigated through field tests and numerical simulations, and the effects of the length of the inner tube insulation and the insulation scheme on the water temperature and heat extraction power of the coaxial heat exchanger are analyzed. The results show that the short-term heat extraction power of the coaxial heat exchanger is 1506.83 kW when a real aerogel insulated tube with a thermal conductivity of 0.06 W/(m·K) is used as the inner tube, and for a geothermal well of 3500 m depth, the thermal insulation performance of the inner tube decreases with increasing depth, and the thermal insulation performance of the 0～1400 m section has a greater influence on the overall heat transfer effect. Increasing the flow rate in the tube can reduce the effective insulation length of the inner tube. The results of the study can be used as a reference for the efficient development and utilization of medium and deep geothermal energy and the optimal design of coaxial heat exchangers.

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Underground coal mine water bin cleaning robot system

Coal Engineering 2022, 54 (11): 205-208. DOI: 10.11799/ce202211036

Abstract （237）

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In order to solve the problems of high work intensity, high risk factor and low work efficiency when cleaning water bunkers in coal mines manually, a water bunker cleaning robot replaces manual cleaning of water bunkers, thus reducing the work intensity and risk of bunker cleaning workers. We develop a water bin cleaning robot system, which integrates coal mud excavation, dewatering and transportation, and realizes timely and efficient cleaning of coal mud in underground coal mine water bins. Detailed introduction of the system composition, principle and function. Analyze the cleaning effect of the water bin cleaning robot through the use of case studies. The application results show that the water bin cleaning robot system is suitable for coal mine underground water bin coal sludge cleaning work, which is of great significance to realize the intelligent construction of coal mine.

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Application of Vacuum Cleaning Technology in Railway Loading Station

WANG 无JING

Coal Engineering 2023, 55 (4): 29-32. DOI: 10.11799/ce202304006

Abstract （164）

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In view of the restrictive conditions such as low work efficiency and harsh cleaning environment in railway loading stations, the application of vacuum cleaning technology in railway loading station is proposed.The full text introduces the vacuum cleaning technology, taking a loading station as an example, from the four aspects of equipment selection, system design, hydraulic check calculation and material recovery, the design process and key points are introduced in detail, and put forward the idea of next technology promotion.

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Safe and Rapid Roadway Heading Technology of High-gas Mines Based on Large-diameter Long Boreholes

Coal Engineering 2023, 55 (4): 40-44. DOI: 10.11799/ce202304008

Abstract （205）

PDF（mobile）（1558KB）（58）

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Analysis on turning characteristics of self-moving and step-forward sup-porting equipment in coal mine

Coal Engineering 2023, 55 (1): 168-174. DOI: 10.11799/ce202301030

Abstract （156）

PDF（mobile）（1520KB）（19）

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Study on Gas Control Technology in the Upper Corner of Fully Mechanized Mining Face in Shendong Mining Area

Coal Engineering 2023, 55 (4): 87-91. DOI: 10.11799/ce202304016

Abstract （217）

PDF（mobile）（1519KB）（35）

In order to solve the problem of gas overrun in the upper corner of the fully mechanized mining face of low gas mines in the northern area of Shendong mining area, a comprehensive treatment technology focusing on gas drainage is adopted, and the drainage processes of upper corner intubation drainage, goaf closed intubation drainage and goaf borehole buried pipe drainage are adopted, together with corresponding auxiliary control technologies, At the same time, the design of the gas drainage chamber and the layout of the pipeline are optimized and improved. By adopting the above technologies, the gas concentration in the return air corner is significantly reduced during the mining of the working face, and the gas extraction rate of the working face reaches 45 ~ 64%, which solves the problem of local accumulation and overrun of the gas in the return air corner during the mining of the working face, This paper introduces the gas control technology of fully mechanized mining face in Shendong mining area.

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Research and application of AI intelligent identification technology in intelligent coal mine

Coal Engineering 2023, 55 (4): 92-97. DOI: 10.11799/ce202304017

Abstract （406）

PDF（mobile）（7480KB）（160）

It is the mainstream trend of the coal industry to improve the management capacity and level of coal mine safety production and promote the safe and high-quality development of the coal industry. The deep integration of AI(artificial intelligence) technology and the coal industry provides new momentum for the coal industry. Based on the analysis of the application of AI intelligent technology, this paper puts forward the overall framework and realization objectives of AI intelligent identification system, establishes the overall solution of INTELLIGENT MINE AI intelligent identification, and designs an AI intelligent analysis platform. The platform, with AI technology as the core, is supported by machine deep learning mathematical model and alarm system. Through machine vision algorithm, real-time analysis of personnel behavior, equipment state, environmental state, non-standard operation and high-risk operation of multiple operation scenarios in coal mine shaft is made, forming software + server intelligent vision application mode. Through machine vision analysis and artificial auxiliary proofreading, the abnormal events can be accurately analyzed, intelligent early warning, real-time tracking, on-site stop and interlock linkage, which has realized the transformation from civil air defense to technical defense, and has guiding significance for improving the coal mine safety production guarantee capacity and exploring the construction of visual and intelligent remote safety management mode

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Research and Application of Collaborative Support Technology for Broken Surrounding Rock in Deep Wells

Coal Engineering 2023, 55 (1): 32-36. DOI: 10.11799/ce202301007

Abstract （253）

PDF（mobile）（4861KB）（33）

In order to solve the problems of large deformation, easy instability and difficult support in roadway support of broken surrounding rock when coal resources enter deep mining, a coordinated support scheme of scaffolding + bolts (cables) + grouting is proposed. The characteristics of surrounding rock structure stability and crack development were determined by drilling peep. FLAC3D numerical simulation compares and analyzes the stress and plastic zone distribution of conventional bolt-shotcrete support, bolt-grouting support and shed bolt-grouting collaborative support. The results show that the shed-anchor-injection synergistic support technology shows better support effect than the other two schemes, the plastic zone distribution range is obviously reduced, the stress concentration phenomenon is alleviated, and the simulated deformation of the support roadway is close to the engineering monitoring. The engineering test shows that: the roadway with conventional bolt mesh and shotcrete support and anchor injection support still has large deformation and cannot maintain long-term stability, and the roof subsidence during the application period is reduced by 68% compared with the conventional bolt-mesh shotcrete support. , the displacement of the two groups is reduced by 52%, which meets the stability requirements of roadway support. The shed-anchor-grouting synergistic support technology has a significant effect on the deformation control of the deep broken surrounding rock roadway, especially in the control of the surrounding rock during the impact period of the excavation.

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Study on Water Conducting Fractured Zone Development Characteristics of Jurassic Extra Thick Coal Seam by Fully-mechanized Caving Mining

Coal Engineering 2023, 55 (1): 59-64. DOI: 10.11799/ce202301012

Abstract （198）

PDF（mobile）（2674KB）（29）

Taking the no.117 fully mechanized top coal caving stope in Jinjitan coal mine as the research object, the paper studies the development regularity characteristics of roof overburden water conducting fractured zone, and constructs the predictive model for the maximum height of water conducting fractured zone induced by the fully-mechanized caving mining of Jurassic extra thick coal seam in Northern Shaanxi with the methods of optical fiber monitoring, post mining borehole flushing fluid leakage observation and fitting calculation. The field monitoring results show that the maximum height of the water conducting fractured zone ranges from 220.82m to 223.75m, the average ratio of the water conducting fractured zone height to the mining height is 20.21, and the calculation result of the predictive model has an average relative error of 2.96% to the measured results. The research result shows that with the advance of the no.117 stope mining, coal seam roof water conducting fractured zone develops rapidly upward; When the top boundary of the water conducting fractured zone develops to soil rock interface, the upward growth rate of water conducting fractured zone decreases rapidly, the key impermeable soil layer has a significant inhibitory effect on the development of water conducting fractured zone; When mining over about 100m, water conducting fractured zone develops to the maximum height; Due to the self-repair characteristic of Lishi loess(Q2l) after being damaged by mining, the maximum height of water conducting fractured zone decreases slightly with the continuous mining, and the development of water conducting fractured zone does not penetrate the key impermeable soil layer. The research conclusion can further provide a scientific reference for safe production and coal seam roof water rush prevention in the coal mine with extra thick coal seam mining in Northern Shaanxi.

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Corrosive mechanism analysis and research on anti-corrosion by zinc-poor coating of protective steel nets in coal mine

Coal Engineering 2023, 55 (1): 143-148. DOI: 10.11799/ce202301026

Abstract （185）

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To solve the problems that seriously corrosive anchor net supporting materials (protective steel nets) in the wet environment of Shendong Coal Group Company, the scanning electron microscope, X-ray diffraction, Fourier transform infrared instrument and electrochemical test were conducted to analyze the morphology, structure and corrosive mechanism of protective steel nets (welded protective nets of 45# steel) taken from the coal lane, respectively. Besides, the anti-corrosion effect of protective steel net covered by the epoxy zinc-poor coating, which is composed of 32% of pigment volume concentration, was studied by immersion of simulated roof water. The results depict that the rust layer on the protective steel nets consist of α-FeOOH, γ-FeOOH, Fe2O3 and Fe3O4 with loose porous structure, leading to continuous corrosion process of the metal matrix. Meanwhile, the epoxy zinc-poor coating is valid to reduce the corrosive rate of protective steel nets down to around 0.001 mm/a by shielding effect. This strategy can effectively simplify the construction process, improve the corrosion resistance and prolong their lifespan of the protective steel nets in coal lane.

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Analysis of Influence Law of Ground Stress Distribution Law on Prominence

Coal Engineering 2023, 55 (2): 69-74. DOI: 10.11799/ce202302013

Abstract （158）

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Abstract: In order to study the influence law of ground stress distribution characteristics on coal and gas protrusion, the method of combining theoretical analysis and field example verification is adopted. That is, through the numerical simulation method, we analyze the influence of the distribution of raw rock stress on the elements of mining stress field and physical and mechanical properties of coal and rock body, and explore the law of influence of stress direction on the protrusion risk of mining surface retraction. The research results show that when the maximum stress direction is perpendicular to the direction of roadway digging or surface recovery, the stress concentration phenomenon is more obvious in front of the working face, the larger the scope of the unloading damage zone, the lower the porosity of the coal body, and the stronger the risk of protrusion at the working face. And combined with the coal and gas protrusion phenomenon in the south one mining area of mulberry pine coal mine and the actual measured data of ground stress, it verifies the phenomenon that the protrusion risk is greater when the maximum main stress direction is perpendicular to the direction of advancement.

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Evolution characteristics of overlying rock fissures under hard and thick strata and their hazard analysis

Coal Engineering 2023, 55 (2): 93-97. DOI: 10.11799/ce202302017

Abstract （243）

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Aiming at the occurrence of hard and thick strata in the overlying strata, a similar model of the hard and thick strata overlying the working face was made by using the method of similar material simulation test, and the structure of the overlying strata and the evolution characteristics of fissures under the hard and thick strata and the analysis of the causation of disasters were studied. The research results show that after the advancing of the working face, the overlying rock layer gradually forms a trapezoidal structure, and the existence of the hard and thick rock layer shields the longitudinal development of the trapezoidal structure; Most of the space created by the gas accumulation creates space for gas accumulation; the fractured fractures and the abscission fractures are connected to each other, forming two-way intercommunication vertical fractured fracture areas on the working face side and the incision side, providing a path for gas migration. The gas released near the mining coal seam enters the maximum abscission crack in the overlying rock along the vertical fracture areas on both sides, and finally accumulates in the maximum separation crack under the hard and thick rock layer that occupies most of the space for coal seam mining.After the hard thick rock stratum is broken, the gas space decreases sharply, the gas pressure rises rapidly, and the gas flows to the working face through the vertical fracture fissure area on both sides, which is easy to induce gas outburst and other disasters.

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Fracture development characteristics and strain evolution of coal samples based on DIC technology

Coal Engineering 2023, 55 (2): 98-104. DOI: 10.11799/ce202302018

Abstract （187）

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In order to deeply analyze the characteristics of crack development and strain evolution of coal samples under uniaxial compression, digital speckle technology was used to obtain the full-process images and data of the crack field and strain field of the specimen during the test. The global cracks development and strain evolution process of the specimen are analyzed, and the internal relationship between strain evolution and crack development is obtained. Based on this, the key cracks of the specimen are selected, the development of local cracks is further analyzed, and the evolution characteristics of the local horizontal strain, vertical strain, maximum principal strain field and the direction of the maximum principal strain with the acquisition frame are clarified. The results show that: the strain evolution of the specimen is potentially related to the development of cracks. There is often obvious strain concentration in the development of cracks, and there will be concentrated distribution of horizontal strain and vertical strain at the inclined or curved cracks. And the horizontal strain concentration is relatively large. In a curved crack, When the degree of opening is large, it is affected by the vertical compressive stress, which tends to produce large vertical deformation, and induce horizontal deformation in the opposite direction. There will be phenomena such as crack closure, sharp increase in vertical strain, and sharp decrease in horizontal strain. When the crack opens or expands, the maximum principal strain increases, and at the same time, there will be obvious strain concentration; When the crack is closed, the maximum principal strain decreases and the strain concentration also decreases; The direction of maximum principal strain is basically the same as the crack opening direction, and is basically perpendicular to the crack propagation direction. In addition, when the acquisition frame reaches 89% of the failure frame of specimen, the specimen's cracks develop rapidly, and thereafter, it also shows rapid concentration of local strains. And when the specimen cracks are generated or destroyed instantaneously, the maximum principal strain direction will also change greatly. The test results can be used as one of the precursors of the specimen failure early warning.

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Research on the High Quality Development Path and Key Issues of Xinjie Taigemiao Mining Area

Coal Engineering 2023, 55 (5): 1-7. DOI: 10.11799/ce202305001

Abstract （613）

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

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Research on fracturing pressure relief roadway protection technology of thin spacing dynamic pressure roadway under disturbance of residual coal pillar

Coal Engineering 2025, 57 (1): 42-51. DOI: 10.11799/ce202501007

Abstract （75）

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In response to the problem of large deformation caused by high stress bearing capacity of dynamic pressure roadways under the conditions of the residual coal pillars disturbance and thin spacing rock layers, taking 10102 transportation roadway of Huangjiagou coal mine as the engineering background, a stress transferring model of the floor under the action of residual coal pillars and multi-state thin interlayer rock layers is established. The stress transfer and coal sliding characteristics under different fracturing angles in the target roadways are elaborated, and fracturing parameters based on stress source and transmission path control are determined. The pressure relief of fracturing roof was carried out on site. Research has shown that the influence of residual coal pillars on the floor is mainly vertical stress, and the pressurization forms the 8+9 coal seam floor loading area under the action of degradation bearing capacity of fractured rock mass and the blocking transmission effect of broken expanding rock mass in goaf. It also generates additional stress on the surrounding rock of 10 coal seam mining roadway, determining the sensitivity angle of the stress concentration boundary line. The fracturing weakening of interlayer rock improves the stress environment of the coal pillar below the roof pre-splitting line and reduces the load-bearing of the remaining coal pillar and the transmission degree of mining-induced stress to 10 coal pillar, obtaining the equivalent fracturing weakening width with 7.5 m. The fracturing with 45° pre-splitting angle corresponds to a horizontal fracturing distance of 12.5 m in the interlayer rock, and the vertical stress, deformation, and coal pillar sliding degree of the target roadway surrounding rock reach the minimum. After fracturing with 45° on site, the fracture network is developed and penetrated, effectively achieving pre-splitting and cutting roof. The deformation of the roof to floor and two roadsides decreased by 60.1% and 65.5% respectively compared to conventional conditions, improving the stability of the surrounding rock and ensuring high production and efficiency of the working face.

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Research on the law of mining pressure appearance and control countermeasures in cross-roadway without coal pillar

Coal Engineering 2023, 55 (5): 39-44. DOI: 10.11799/ce202305007

Abstract （223）

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

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A Fresh Understanding about Advanced Influence of Surface Movement

Coal Engineering 2023, 55 (2): 105-109. DOI: 10.11799/ce202302019

Abstract （194）

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TIn order to explore the nature of the advance influence of the surface movement, mechanism of the key layer rupture on the advance influence of the surface movement was revealed. Based on the theory of key strata, this paper analyzes the influence mechanism of surface movement and deformation in advance. By analyzing the internal displacement monitoring records of boreholes in Shendong mining area, the results of physical similarity simulation tests, the occurrence law of rock pressure in fully mechanized mining face, and the observation records of surface subsidence, the relationship between the key strata break and the periodic variation of the influence distance (angle) are studied. The results show that the advance influence distance (angle) is not a constant, but a variable that changes periodically. A new viewpoint that the difference between the maximum value and the minimum value of the advance influence distance is roughly equal to the periodic weighting length of the working face is put forward originally. Examples show that the new viewpoint is scientific and reasonable. The paper provides a new technical idea for the organic unity of mining pressure and surface deformation.

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