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Table Of Contents, The Editors Dec 2020

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.


Application Of High-Precision 3d Seismic Exploration Technology In Huainan Mining Area, Liu Jun, Zhao Wei, Han Biwu Dec 2020

Application Of High-Precision 3d Seismic Exploration Technology In Huainan Mining Area, Liu Jun, Zhao Wei, Han Biwu

Coal Geology & Exploration

In order to deeply analyze the indication of oil shale development characteristics on paleoenvironments and provide theoretical guidance for oil shale resource evaluation, the organic geochemistry and elemental geochemistry characteristics of the Neogene Zhangcun Formation oil shale in the central part of the Qinshui basin were analyzed by Rock-Eval and TOC and the paleoclimate and paleogeographic environments of the depositional period were discussed as well. The results show that the oil shale of Zhangcun Formation has the low oil content which Tar=4.15%, higher hydrocarbon potential, kerogen is of sapropel type(I1), which has relatively shallow burial depth. The element …


Discussion On Parameters Of High Density 3d Seismic Exploration Acquisition In Coal Mining Districts, Cheng Jianyuan, Wang Qianyao, Zhu Shujie Dec 2020

Discussion On Parameters Of High Density 3d Seismic Exploration Acquisition In Coal Mining Districts, Cheng Jianyuan, Wang Qianyao, Zhu Shujie

Coal Geology & Exploration

In order to improve the light tar and gas yield, the yield distribution and composition characteristics of pyrolysis products of bituminous coal from Shaanxi Hongliulin in the nitrogen atmosphere and weak oxygen atmosphere were studied in a fixed bed reactor. The results showed that the yield of char and tar were reduced under the weak oxygen atmosphere, and the yield of CO and CO2 increased significantly, leading to the increase of total gas yield. Due to the oxidation combustion reaction, the yield of H2, CH4 and C2-C3 gradually decreased with the increase of …


Reception Test And Analysis Of Different Geophones In Coal Mining Districts Seismic Exploration, Zhang Libing, Dong Shouhua Dec 2020

Reception Test And Analysis Of Different Geophones In Coal Mining Districts Seismic Exploration, Zhang Libing, Dong Shouhua

Coal Geology & Exploration

During the development process of coalbed methane, the aggregation and sedimentation of coal fines can block the migration channel of coalbed methane and lead to accidents such as stuck pump and buried pump. In order to find out the aggregation and sedimentation characteristics of coal fines with different particle sizes, the aggregation and sedimentation experiments of coal fines with the particle size>140 mesh(<106 μm), 70 to 140 mesh(106-212 μm) and 50 to 70 mesh(212-300 μm) in deionized water were carried out. The aggregation and sedimentation characteristics of coal fines with different particle sizes in deionized water suspension were investigated from the suspension observation, the concentration characteristics of coal fines and the particle size distribution of coal fines in suspension. The results show that with the increase of the time, the color of coal fines suspension becomes lighter to different degrees, and the stratification of coal fines suspension gradually appears, and the suspension of coal fines with the particle size more than 140 mesh was the first to stratify among three suspensions. The smaller the particle sizes of coal fines, the more coal fines float on the top of the suspension, and the larger the particle sizes of coal fines, the more coal fines sink to the bottom of the suspension. The concentration of coal fines in the suspensions decreased to different degrees with the increase of the time. The concentration of coal fines decreased the fastest within 3 minutes after stopping the stirring. The concentration of coal fines with the particle sizes of 70 to 140 mesh in suspension was the largest among three suspensions. According to the particle size distribution curves, the process of aggregation and sedimentation of coal fines was divided into three stages: single peak to double peak(rapid floating and settlement of coal fines), double peak to single peak(rapid accumulation and settlement of coal fines) and single peak(slow sedimentation of coal fines). Coal fines with particle size more than 140 mesh in the suspension was the first to reach the stage of slow sedimentation, and coal fines with particle size of 70-140 mesh in the suspension reached the stage of slow sedimentation at the latest among three suspensions. The mechanism of aggregation and sedimentation of coal fines was discussed from the aspects of the force of coal fines, the extended DLVO theory, and the organic molecular structure of coal fines. The coal samples contain a large number of hydrophobic groups, such as aliphatic hydrocarbon and aromatic hydrocarbon, therefore, they have strong hydrophobicity and low wettability. With the decrease of particle sizes of coal fines, its specific surface area increases significantly, and a large amount of air is absorbed on the surface of coal fines, forming an air film. At the same time, particles of coal fines are adsorbed and aggregated with each other, and many micro pores are formed inside, resulting in that coal fines with small particle size is easy to aggregate and float on the suspension surface.


Application Of Broadband And Wide Azimuth Processing Technology In Full Digital High Density Seismic Exploration In Huaibei Mining Area, Yang Guangming, Jin Xueliang, Zhang Xianxu, Zhi Min, Shan Rui Dec 2020

Application Of Broadband And Wide Azimuth Processing Technology In Full Digital High Density Seismic Exploration In Huaibei Mining Area, Yang Guangming, Jin Xueliang, Zhang Xianxu, Zhi Min, Shan Rui

Coal Geology & Exploration

During coalbed methane well drilling, the drilling fluid contaminates and blocks the pores and fractures of coal seam. In order to find out the difference of pollution degree of drilling fluid coal and the contribution rate of the pores and fractures of different scale to permeability, the coal of Changping mine was taken as the research object, the scanning electron microscopy(SEM) and the Image Pro Plus(IPP) processing technology were used, the parameters such as the average length, the average width, the total area and the total perimeter of the fractures of different scales in coal before and after contamination were …


Pulverized Coal-Controlling Method Based On Supermolecular Film In Cbm Well, Wu Ying, Li Xiaonan, Liu Zixiong, Liu Rumin Dec 2020

Pulverized Coal-Controlling Method Based On Supermolecular Film In Cbm Well, Wu Ying, Li Xiaonan, Liu Zixiong, Liu Rumin

Coal Geology & Exploration

Correctly understanding the micro-scale fracture characteristics of the Lower Cambrian shale and the evolution law of acoustic emission signals are of great reference value in the study of shale mechanical characteristics, fracture mechanism and shale gas development and utilization. In this paper, based on digital image processing technology, the non-uniform characterization of quartz-filled shale is carried out, and a numerical model is established using the real rock fracture analysis system RFPA2D-DIP to simulate the failure process of shale under different confining pressures. The test results show that under the micro-scale structure, the shale failure mode can be roughly …


Characteristics And Monitoring Method Of The Trajectory Of The Radial Cbm Well, Xin Kai, Ji Changjiang, Xiao Chun Dec 2020

Characteristics And Monitoring Method Of The Trajectory Of The Radial Cbm Well, Xin Kai, Ji Changjiang, Xiao Chun

Coal Geology & Exploration

The in-situ stress of 3-1 coal seam in Hongqingliang coal mine was measured by hollow core inclusion measurement, and distribution characteristics of in-situ stress field were obtained in order to solve the problem of serious deformation in mining roadway. Fault structures of grade Ⅰ-Ⅴ in Hongqingliang coal mine were divided by geo-dynamic division method, and the stress areas were divided and the stability of roadways was analysis by rock stress state analysis system. The research showed that the in-situ stress field in Hongqingliang coal mine belongs to the horizontal tectonic stress field, which is dominated by horizontal compressive stress. The …


Freezing Temperature Field Characteristics Of Multi-Loop Pipers Under Different Working Conditions At The Interface Of Deep Thick Sand And Clay, Yang Qing, Rong Chuanxin, Li Mingjing, Yang Guobing Dec 2020

Freezing Temperature Field Characteristics Of Multi-Loop Pipers Under Different Working Conditions At The Interface Of Deep Thick Sand And Clay, Yang Qing, Rong Chuanxin, Li Mingjing, Yang Guobing

Coal Geology & Exploration

When drilling in a complex heterogeneous formation, due to the limitation of bit crown shape, the cutters of each part of the bit are subjected to non-uniform force, and the cutters at the local location are subjected to large impact load, which lead to the occurrence of bit vortex. In order to solve the problem, a “multi-level force balance” cutter circumferential arrangement scheme is proposed. By establishing the rock breaking finite element simulation model of the bit, the mechanical characteristics of the cutter and the bit under three circumferential cutter distribution modes(clockwise, counterclockwise and “multi-level force balance”) are analyzed. Simulation …


Late Pleistocene Sedimentary Features And The Palaeoclimatic Background In Hongsibao Basin, Li Zhenhong, Cui Jiawei, Li Chaozhu, Jiang Boyu, Huang Ting Dec 2020

Late Pleistocene Sedimentary Features And The Palaeoclimatic Background In Hongsibao Basin, Li Zhenhong, Cui Jiawei, Li Chaozhu, Jiang Boyu, Huang Ting

Coal Geology & Exploration

The chuck is an important part of the coal mine tunnel drilling rig. The performance of the chuck directly affects the efficiency and quality of drilling. Aiming at the problems of the rubber cylinder hydraulic chuck. a new radial piston hydraulic chuck is studied. The objective of this paper is to devise a new radial piston hydraulic chuck instead of rubber-sleeve hydraulic chuck. Then, the motion mathematical model of radial piston hydraulic chuck was established based on the radial piston chuck clamping and loosening of system structure and working principle. At the same time, a dynamic co-simulation of chuck hydraulic …


Hydrogeological Characteristics And Danger-Solving Mining Of Jurassic Baotashan Sandstone—A Case Study In New Shanghai No.1 Coal Mine, Lyu Yuguang, Liu Baokai, Zhao Baofeng, Lyu Wenqing, Han Gang, Wang Yongbao Dec 2020

Hydrogeological Characteristics And Danger-Solving Mining Of Jurassic Baotashan Sandstone—A Case Study In New Shanghai No.1 Coal Mine, Lyu Yuguang, Liu Baokai, Zhao Baofeng, Lyu Wenqing, Han Gang, Wang Yongbao

Coal Geology & Exploration

In order to make up for the deficiency of the regional monitoring of the traditional gas drainage monitoring system, this paper proposes to build a borehole gas drainage monitoring system with borehole as the monitoring unit, which can dynamically grasp the drainage effect of each borehole in the process of gas drainage in real time, change the large area regional measurement into the measurement of each borehole in the region, and realize the fine monitoring of gas drainage. According to the requirements of borehole gas drainage monitoring system, combined with the characteristics of gas drainage parameters at the borehole orifice, …


Mechanism Of Aggregate Start-Up Process And Coupling Of Two-Phase Flow In Hydrodynamic Roadway, Mou Lin Dec 2020

Mechanism Of Aggregate Start-Up Process And Coupling Of Two-Phase Flow In Hydrodynamic Roadway, Mou Lin

Coal Geology & Exploration

Adding heat-conducting filler to the cement of the geothermal well could significantly improve the thermal conductivity of the cement stone and enhance the heat extraction effect of the geothermal well. In this study, on the basis of summarizing the heat conduction path theory and concept of high packing density, the effects of different filler types, particle sizes and dosages on the thermal conductivity of cementing cement were investigated through experiments. The test results showed that graphite had the best effect on improving the thermal conductivity of cement stone compared to other types of filler; the larger the graphite particle size, …


High Rank Coal Structure And Log Interpretation Method Of Fracture Pressure In Shouyang Block, Li Songlin, Li Zhongcheng, Wang Lina, Duan Jing, Xiang Nian Dec 2020

High Rank Coal Structure And Log Interpretation Method Of Fracture Pressure In Shouyang Block, Li Songlin, Li Zhongcheng, Wang Lina, Duan Jing, Xiang Nian

Coal Geology & Exploration

In order to accurately describe the distribution of surface subsidence basin, and based on the power exponential function model and the subsidence features, the surface subsidence basin model of long-wall working face along strike with gently inclined coal seam was established concerned the combination of theoretical analysis and numerical simulation method. The influencing factors of model parameters and the changing patterns of parameters were analyzed, and the applicability and the predicting accuracy of the model were verified. The results showed that parameter n reflected the range of the bottom size of the sinking basin, which was mainly related to the …


Biogas Production Of Lignite And Variation Characteristics Of Cations In Liquid Phase System, Zhao Han, He Huan, Wang Jiangze, Song Yanli, Niu Jianglu, Chen Linyong, Guo Xin, Liu Jian, Guan Jiadong, Yuan Xuefang Dec 2020

Biogas Production Of Lignite And Variation Characteristics Of Cations In Liquid Phase System, Zhao Han, He Huan, Wang Jiangze, Song Yanli, Niu Jianglu, Chen Linyong, Guo Xin, Liu Jian, Guan Jiadong, Yuan Xuefang

Coal Geology & Exploration

Liupan Shan lies between the Tibetan plateau and Ordos block and has been under the remote effect of the northeastward extension of the Tibetan plateau. The former research about the uplift of Liupan Shan mainly focused on the petrology, structural deformation or tectonic evolution study from the Cretaceous to early period of Cenozoic. However, the Late Pleistocene geological study closely connected with the human activities was rarely mentioned. In this study, we carried out systematic sedimentary research in the Qingshuihe basin adjacent to the Liupan Shan tectonic belt, re-determine the sedimentary sequence at first, then reverse the uplift history of …


Analysis On The Cbm Extraction Effect Of The Horizontal Wells In The Coal Seam Roof In Luling Coal Mine In Huaibei, Fang Liangcai, Li Guihong, Li Dandan, Li Haozhe, Liu Jia Dec 2020

Analysis On The Cbm Extraction Effect Of The Horizontal Wells In The Coal Seam Roof In Luling Coal Mine In Huaibei, Fang Liangcai, Li Guihong, Li Dandan, Li Haozhe, Liu Jia

Coal Geology & Exploration

Aiming at the scientific evaluation of coaxial casing heat transfer of geothermal resources with medium burial depth(1 500-4 000 m), a rock-water coupled heat transfer model of a vertical single well was built based on the simulation platform of COMSOL Multiphysics software. Taking the stratigraphic and geothermal characteristics of Xi'an area as the simulation background, the heat transfer capacity of single well(3 500 m)casing under two different geothermal gradients(0.027℃/m and 0.030℃/m) and four flow velocities(0.25, 0.50, 0.75, 1.00 m/s) was calculated and analyzed. Meanwhile, the numerical models of group wells with five kinds of well spacing were established, and the …


The Application Of Ovt Domain Processing Technology In Deep Cbm Exploration In Qinshui Basin, Tian Zhongbin, Li Juan, Shen Youyi, Feng Ajian, Yang Xiaodong Dec 2020

The Application Of Ovt Domain Processing Technology In Deep Cbm Exploration In Qinshui Basin, Tian Zhongbin, Li Juan, Shen Youyi, Feng Ajian, Yang Xiaodong

Coal Geology & Exploration

The high concentration slurry is poured into the goaf to form filled piers. The bearing capacity of the piers to the superstructure are affected by the overlap size. In order to grasp the influence of the overlap size on the bearing capacity of the overlying rock layer, high concentration slurry was prepared which selected cement as the cementing material, standard sand as the aggregate. 3D printing technology was used to make the mold to produce the overlapped round table samples. The uniaxial compression test was carried out. Test results show that, when the top area and height of each single …


Research On The Fracture Mechanics Model Of Deep Hole Pre-Splitting For Forced Caving, Li Jinhua, Chen Wenxiao, Su Peili, Duan Dong, Song Yongjun Dec 2020

Research On The Fracture Mechanics Model Of Deep Hole Pre-Splitting For Forced Caving, Li Jinhua, Chen Wenxiao, Su Peili, Duan Dong, Song Yongjun

Coal Geology & Exploration

Tight radius drilling technology based on high pressure water jet is an important technical means to realize low-cost and efficient development of oil and gas resources. According to the research and application of tight radius drilling technology based on high pressure water jet, the equipment buildup, drilling theory, technical process and application effect of three tight radius drilling technologies and equipments(i.e., forging milling and reaming hydraulic type, forging milling and reaming jet thrust type and casing window type) are summarized systematically, and the advantages, disadvantages and adaptability of different technologies are included. From the point of view of increasing production …


Construction And Transformation Technology Of Three-Dimensional Fine Model Of Mine Water Diversion Structure, Fan Juan, Hou Enke, Jin Dewu, Qiao Wei, Nan Shenghui Dec 2020

Construction And Transformation Technology Of Three-Dimensional Fine Model Of Mine Water Diversion Structure, Fan Juan, Hou Enke, Jin Dewu, Qiao Wei, Nan Shenghui

Coal Geology & Exploration

The development degree of natural fractures is the main factor affecting coalbed methane productivity. In order to accurately obtain the distribution position of the natural fractures in the a coalbed methane field in the southern Qinshui basin, 7 refracturing wells in the area were adopted by surface microseismic vector scanning to monitor the natural fractures. A certain amount of three-component geophones were deployed around the fracturing well to collect microseismic events in the surrounding reservoir during fracturing, and after Semblance superposition, the fracture energy slices at different times in the monitoring area were obtained to explain the natural fractures in …


Gas Drainage Technology And Practice Analysis Of Large Diameter High Position Directional Long Borehole, Hao Shijun, Duan Huijun, Mo Haitao, Peng Xu, Peng Dong Dec 2020

Gas Drainage Technology And Practice Analysis Of Large Diameter High Position Directional Long Borehole, Hao Shijun, Duan Huijun, Mo Haitao, Peng Xu, Peng Dong

Coal Geology & Exploration

In order to solve the problem of the high mud content and easy hydration and dispersion of the Cretaceous sedimentary strata in well Songke-2, the bit balling is prone to occur in the water-based drilling fluid environment, which affects the drill bit ROP and induces downhole adhesion stuck, the paper combined the core drilling technology of well Songke-2, systematically analyzed of the causes of bit balling generated by the drill bit in the mudstone and water-based drilling fluid environment, provided a basis for the design of the anti-balling of the drill bit and the formulation of the anti-ball in drilling …


Pattern And Effect Of The High Density 3d Seismic Exploration In Coal Mining Districts, Jin Xueliang, Wang Qi Dec 2020

Pattern And Effect Of The High Density 3d Seismic Exploration In Coal Mining Districts, Jin Xueliang, Wang Qi

Coal Geology & Exploration

Graphene is an emerging carbon nanomaterial in the 21st century, has excellent properties and shows great application potential in many fields. Coal is the most abundant and the cheapest carbon source with unique structure and material composition. The application of coal in the development and the application of new carbonaceous materials such as graphene and their composites is a work worthy of further exploration. The development of coal-based graphene can both promote the clean utilization of coal and enhance the added value of coal resources. In this paper, the research developments in coal structure, the mechanism of coal graphitization, as …


Summary Of High Density 3d Seismic Exploration In The Mining Districts Of Coal Mines In Shanxi Province, Hou Zeming, Yang Deyi Dec 2020

Summary Of High Density 3d Seismic Exploration In The Mining Districts Of Coal Mines In Shanxi Province, Hou Zeming, Yang Deyi

Coal Geology & Exploration

Based on the analysis of geological characteristics of the study area, it is considered that the geological conditions of H2S occurrence are the capping effect of dense surrounding rock on the roof and floor, the water-conducting fractured zone is unable to guide the overlying aquifer, and the low degree of coal metamorphism is not conducive to H2S adsorption, resulting in maximum H2S concentration of about 0.001 4% in the main mined coal seam 4 during the construction of Yadian mine at the north of Binchang mining area. Through the analysis of sulfur distribution, sulfate …


Analysis Of Channel Imaging Effect Of High Density And Conventional Observation System, Zhang Xianxu Dec 2020

Analysis Of Channel Imaging Effect Of High Density And Conventional Observation System, Zhang Xianxu

Coal Geology & Exploration

Aiming at the problems of uncontrollable trajectory, shallow borehole depth and poor gas extraction effect in gas treatment drilling of broken soft coal seam in Qinglong coal mine, the regional progressive gas extraction technology in broken soft coal seam based on compressed-air directional drilling was proposed, on the basis of analyzing the technical bottleneck of existing gas extraction borehole with rotary drilling. The principle and advantage of the technology was expounded, the technology of directional drilling by compressed-air, the technology of long distance in-seam drilling, and the technology of compound slag discharge by double power were integrated. The field test …


High Density 3d Seismic Data-Driven Comprehensive Interpretation Method Of Magmatic Intrusion Zones In Coal Seams And Its Application, Shan Rui, Zhang Guangzhong, Wang Qianyao, Yang Guangming Dec 2020

High Density 3d Seismic Data-Driven Comprehensive Interpretation Method Of Magmatic Intrusion Zones In Coal Seams And Its Application, Shan Rui, Zhang Guangzhong, Wang Qianyao, Yang Guangming

Coal Geology & Exploration

Ordovician limestone karst water is the main threatening water source for mining activities in Baode coal mine, and it is one of the main water supply sources. Ordovician limestone karst water samples were systematically collected in Baode coal mine, and the methods of correlation analysis, ion proportional coefficient, saturation index inversion simulation and Chlor-Alkali index were chosen to analyze the hydrochemical characteristics and its formation mechanism. The results showed that the water quality types of Ordovician limestone water changed from runoff zone to stagnant zone in a trend of HCO3-Na(Na·Ca)→HCO3·Cl-Na·Ca(Ca·Mg)→Cl-Na(Na·Ca). The mass concentration of each ion …


Sedimentary Response To The Uplift Of The Liupan Shan Since The Late Pleistocene And Its Environmental Effects, Ma Zhaoying, Dong Xiaopeng, Zhang Qing, Cui Jiawei Oct 2020

Sedimentary Response To The Uplift Of The Liupan Shan Since The Late Pleistocene And Its Environmental Effects, Ma Zhaoying, Dong Xiaopeng, Zhang Qing, Cui Jiawei

Coal Geology & Exploration

Liupan Shan lies between the Tibetan plateau and Ordos block and has been under the remote effect of the northeastward extension of the Tibetan plateau. The former research about the uplift of Liupan Shan mainly focused on the petrology, structural deformation or tectonic evolution study from the Cretaceous to early period of Cenozoic. However, the Late Pleistocene geological study closely connected with the human activities was rarely mentioned. In this study, we carried out systematic sedimentary research in the Qingshuihe basin adjacent to the Liupan Shan tectonic belt, re-determine the sedimentary sequence at first, then reverse the uplift history of …


The Pca-Logistic Method For Identification Of Water Burst In Nalinhe No.2 Coal Mine, Ji Zhuochen, Ding Xiang, Hou Enke, Pu Zhiguo, Xie Peng Oct 2020

The Pca-Logistic Method For Identification Of Water Burst In Nalinhe No.2 Coal Mine, Ji Zhuochen, Ding Xiang, Hou Enke, Pu Zhiguo, Xie Peng

Coal Geology & Exploration

Nalinhe No.2 coal mine is the first pair of large-scale mines in the Nalinhe mining area. The water inrush events occur from time to time due to its own complex hydrogeological conditions and strong disturbance of excavation in the initial stage of production, which has caused serious threat to the mining activity safety. Finding the source of gushing water quickly and effectively is the key to control the mine water disaster. Based on the water quality analysis of main aquifers and goaf water samples in Nalinhe No.2 coal mine, and drawing the piper trilinear nomograph water samples, the hydrogeochemical characteristics …


Damaged Constitutive Model Of Frozen Sand Under The Influence Of Intermediate Principal Stress, Ma Shilong, Yao Zhaoming, Liu Shuang, Pan Xuan Oct 2020

Damaged Constitutive Model Of Frozen Sand Under The Influence Of Intermediate Principal Stress, Ma Shilong, Yao Zhaoming, Liu Shuang, Pan Xuan

Coal Geology & Exploration

Artificial freezing is a commonly used method for stopping water and providing temporary support during the excavation of saturated sand. This study on the damage characteristics of frozen soil lays the foundation for the analysis of the mechanical properties of frozen soil and the stability of frozen bodies. In order to study the damage mechanical properties of frozen sand, three-dimensional laboratory tests on frozen sand with different intermediate principal stress coefficients were carried out at -5℃. Based on the Weibull random distribution of micro element failure of frozen soil, the Drucker-Prager strength criterion was invoked as the statistical distribution variable, …


Effect Of Thermally Conductive Filler On Thermal Conductivity Of Cementing Materials In Geothermal Wells, Yang Yu, Xu Shuanhai, Zhang Hao, Han Yongliang, Zhang Weidong Oct 2020

Effect Of Thermally Conductive Filler On Thermal Conductivity Of Cementing Materials In Geothermal Wells, Yang Yu, Xu Shuanhai, Zhang Hao, Han Yongliang, Zhang Weidong

Coal Geology & Exploration

Adding heat-conducting filler to the cement of the geothermal well could significantly improve the thermal conductivity of the cement stone and enhance the heat extraction effect of the geothermal well. In this study, on the basis of summarizing the heat conduction path theory and concept of high packing density, the effects of different filler types, particle sizes and dosages on the thermal conductivity of cementing cement were investigated through experiments. The test results showed that graphite had the best effect on improving the thermal conductivity of cement stone compared to other types of filler; the larger the graphite particle size, …


Simulation And Experimental Study On Dynamic Characteristics Of Radial Piston Hydraulic Chuck, Liang Chunmiao, Yao Ningping, Yao Yafeng, Li Kun, Peng Tao, Song Haitao Oct 2020

Simulation And Experimental Study On Dynamic Characteristics Of Radial Piston Hydraulic Chuck, Liang Chunmiao, Yao Ningping, Yao Yafeng, Li Kun, Peng Tao, Song Haitao

Coal Geology & Exploration

The chuck is an important part of the coal mine tunnel drilling rig. The performance of the chuck directly affects the efficiency and quality of drilling. Aiming at the problems of the rubber cylinder hydraulic chuck. a new radial piston hydraulic chuck is studied. The objective of this paper is to devise a new radial piston hydraulic chuck instead of rubber-sleeve hydraulic chuck. Then, the motion mathematical model of radial piston hydraulic chuck was established based on the radial piston chuck clamping and loosening of system structure and working principle. At the same time, a dynamic co-simulation of chuck hydraulic …


Table Of Contents, The Editors Oct 2020

Table Of Contents, The Editors

Coal Geology & Exploration

No abstract provided.


Progressive Gas Extraction Technology In Broken Soft Coal Seam Of Qinglong Coal Mine, Guizhou Province, Liang Daofu, Cao Jianming, Dai Mao, Chu Zhiwei, Zhang Lei Oct 2020

Progressive Gas Extraction Technology In Broken Soft Coal Seam Of Qinglong Coal Mine, Guizhou Province, Liang Daofu, Cao Jianming, Dai Mao, Chu Zhiwei, Zhang Lei

Coal Geology & Exploration

Aiming at the problems of uncontrollable trajectory, shallow borehole depth and poor gas extraction effect in gas treatment drilling of broken soft coal seam in Qinglong coal mine, the regional progressive gas extraction technology in broken soft coal seam based on compressed-air directional drilling was proposed, on the basis of analyzing the technical bottleneck of existing gas extraction borehole with rotary drilling. The principle and advantage of the technology was expounded, the technology of directional drilling by compressed-air, the technology of long distance in-seam drilling, and the technology of compound slag discharge by double power were integrated. The field test …


Method And Practice Of Quality Test After Grouting In Coal Mine Goaf, Liu Xiaoping, Li Shan, Liu Xinxing, Cao Xiaoyi, Wang Yutao Oct 2020

Method And Practice Of Quality Test After Grouting In Coal Mine Goaf, Liu Xiaoping, Li Shan, Liu Xinxing, Cao Xiaoyi, Wang Yutao

Coal Geology & Exploration

Grouting quality test is the key technology for efficient development and utilization of waste land in the goaf of a coal mine, it is of great significance to evaluate the stability of the site and the safety of construction after goaf management. Based on many engineering practices, this paper summarizes the evaluation method of the qualified standards of the grouting quality and the errors existed in the testing work. The results proved that the quality inspection after grouting is a systematic work. The test method could be optimized according to the characteristics of the construction and grouting design requirements, following …