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2019 Vol. 4, No. 4

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Analysis of soil moisture changes of the Buertai mining area based on TVDI
Xu Xia, Sun Wenbin, Wang Zhen
2019, 4(4): 285-291.
Abstract(686) PDF(193)
Abstract:
It is of great significance to monitor the change of soil moisture in mining areas in the fields of resource exploitation,ecological protection and drought waening in western China the Buertai mining area affiliated to Shendong coal group as the study area OLI time series satellite images with similar phases taken from 2000 to 2017 were used to extract the normalized difference vegetation index(NDVI)and land surface temperature(LST),in order to construct NDVI-LST spectral feature space and calculate the temperature vegetation dryness index(TVDI)of the mining area. Then,spatial distribution map of the soil moisture grade in the mining area was made to analyze the variation trends of soil moisture in the mining area and its influencing factors showed that under the consistent condition of vegetation phenology in August and September,the surface soil moisture in the Buertai mining area showed an increasing trend from 2000 to 2017,and there was no obvious drying phenomenon,which was related to the artificial restoration of the mining area and the improvement of the mining environment.
Study on 3D seismic interpretation and development characteristics of active faults in Gugui mining area
Shi Suzhen, Gu Jianying, Guo Jiacheng, Liu Zhongyuan, Li Yuying
2019, 4(4): 292-298.
Abstract(485) PDF(121)
Abstract:
In order to investigate the development characteristics of the Gugui fault depression zone,a 3D seismic approach was used for the study.First ,a high-resolution seismic data processing was performed on the faulted zone by using the method of prestack time migration.In the case of accurate homing , seismic attributes and 3D visualization analysis were used and a full 3D interpretation method through combination of body-surface-line-point were used to inversigate fully implement faults in the Cenozoic development in the study area.On this basis ,a time-depth conversion was made on the Doon boundary of the Cenozoic and a depth contour map was obtained and A total of 8 active faults were interpreted in the region , and it was found through statistics that these faults were basically north-west oriented and tending to be almost upright with strong developmental regularity.With long extension length and large cutting depth , some faults also develop faults in the coal-bearing strata.With the influence of mining and the release of stress , fault dislocation surface could be widened ,and it may form a water flow channel.Therefore, it is a major threat to the safe mining of coal mines and must be given sufficient attention.
Study on influence of advanced deep-hole blasting pre-splitting roof on stability of gob side entry retaining
Hu Tao, Hou Gongyu, Li Zixiang, Li Zhuhe, Xie Bingbing, Chen Jianpeng, Cui Yongke
2019, 4(4): 299-307.
Abstract(691) PDF(138)
Abstract:
In order to smoothly implement gob-side entry retaining and mining without coal pillar in 3207 working face of Nanyang Coal Mine, Shanxi Province , this paper proposes to carry out advanced deep-hole blasting pre-splitting roof near gob side supporting wall. 'Through numerical simulation and field industrial test , the influence of deep-hole blasting roof cutting on surrounding rock stability of gob-side retaining roadway is studied.Based on the backdrop of retaining roadway along goaf in 3207 working face of Nanyang coal mine ,a numerical simulation model was established , the displacement of roof and floor ,wall and coal body of retained roadway, the stress distribution and variation of surounding rock of retaining roadway were calculated.The numerical calculation shows that the variation of stress and displacement of surrounding rock in gob-side retaining roadway decreases greatly after roof cutting , and the stability of surrounding rock is improved significantly.The field industrial test results show that deep -hole blasting roof cutting can effectively eliminate the rotational extrusion damage of cantilever beam roof to surounding rock of gob-side retaining roadway , and help to maintain the stability and integrity of gob-side retaining roadway structure. The research results of this paper can be used for reference in the design and construction of gob-side entry retaining project.
Study on micromechanism of water absorption and its softening effect on shale rock in deep coal measures
Zhang Na, Wang S huibing, He Xiao, Li Jiabin, Gao Weihao
2019, 4(4): 308-317.
Abstract(517) PDF(117)
Abstract:
Water absorption experiments under ietnt inae using a self-developed hydrophilic experishale samples collected from Shenyang of Liaoning province using a self-developed hydrophilic experimental system.At the same time,X-ray diffraction , high pressure mercury intrusion , scanning electron microscope and uniaxial compression experiments were periormea on lteosthadl water increases with time after water absorption.The experimental results are as follows:①the absorbed water increases with time while the water absorption rate decreases with ume and wttlh slale sam ples under different water presexponential function;②the water absorption capacities of the shale samples under different water pressures are remarkably different which are suggesting that water pressure can significantly increase the water absorptivity;③the water absorption capacity and the clay mineral content are positively correlated which indicates that the clay minerals ,specifically illite , plays an important role in water absorption process of the shale samples;④the water absorption capacity and the effective porosity are negatively correlated and the reasons are closely related to a micro-structural perspective;⑤the uniaxial compression strength(UCS)of the hydrated shale samples is negatively correlated with their water content and the increase of the porosity after water absorption may be an important reason for decreased strength of the hydrated shale samples.
Numerical simulation on the influence of borehols arrangement and delay time on coal crushing effects
LiuFei, Chang Kunlin, Li Meng
2019, 4(4): 318-326.
Abstract(509) PDF(109)
Abstract:

According to the effect of different charging and boreholes arrangements and delay time on coal crushing effect in coal blasting,this paper used ANSYS-LS/DYNA to carry out numerical simulation and analyzed the calculation results.The results show that the explosion stress wave has an supper position effect in the coal , and the coal is mainly broken by tensile.With the increase of ratios of borehole distance and row distance , the crushing of the coal increased first and then decreased.When the ratio of borehole distance and row distance is 1.5, the peak stress in the center of the triangular of boreholes and the degree of coal fragmentation reached the maximum , which are about 175 MPa and 9.6% , respectively.The cracks around the empty hole were annularly distributed.When a/b were 1.0 or 1.5,the cracks were mainly concentrated inside the triangle.When the delay time between boreholes is 0.5 ms,the cracks dispersion is larger than that of 1.0 ms.The number of cracks increases with the increase of delay time between rows.
Study on proportion optimization of coal-based solid wastes filling materials
Tang Yuesong, Zhang Lingfei, Lu Huayong
2019, 4(4): 327-336.
Abstract(684) PDF(103)
Abstract:
The aim of this study is to prepare a low cost and high strength filling material.Coal gangue is aggregate.Fly ash,desulfurization gypsum and silicium-calcium slag are cementing materials.The uniaxial compressive strength , slump and slump flow of the specimen were measured to investigate the mechanical properties and the influence of each component.The result shows that desulphurization gypsum content and silicium-calcium slag have a strong gelation effect in certain amount range.With the increase of content of fly ash , the initial strength of filling material increases slowly.The content of fly ash should be controlled less than 6.67%.The mixing of fly ash and silicium-calcium slag could activate cementious properties of silicium-calcium slag performance.The optimum mass ratios of coal gangue,fly ash,desulfurization gypsum,silicium-calcium slag and cement are70:6:3:12.5:8.5.The conclusion is verified by response surface method,and the experimental results are consistent with the prediction.
Statics analysis model for rock burst of driving faces with stress inclusions
Yang Xiaobin, Zhou Jie, Zhang Zipeng
2019, 4(4): 337-342.
Abstract(599) PDF(182)
Abstract:
Local dynamic phenomena or dynamic disasters such as rock burst.oen occur in u tlalard faces of underground rock roadway. In order to study its occurrence mechanism,based on the“locked in”stress hypothesis , a simplified mechanical model with a stress inclusion was established.Based on the basic theory of elastic mechanics,the stress distribution formula and the maximum principal stress formula of the driving face with a stress inclusion were derived.Based on the maximum principal stress criterion,when the rock roadway is located at a certain distance from the inclusion,the rock between the fracture planes along the direction of maximum principal stress could move to the excavation space under the combined action of overlying strata and stress inclusions,and form a V-shaped blasting pit.The research in this paper can explain the rock burst phenomena of driving face to a certain extent,and provide theoretical support for preventing rock burst.
 
Study on performances and influence factors of mud foam
Zhu Hongqing, Hu Chao, Zhou Quantao, Li Jiacheng, Wu Bo, Chen Wei
2019, 4(4): 343-348.
Abstract(551) PDF(192)
Abstract:
Spontaneous combustion of coal is a serious threat to the safety production pocess of coal mine,the traditional technology of coal spontaneous combustion control such as grouting in not good.Mud foam is a new type of fire-fighting material,and the influence factors,major-minor sequence of factors and optimum proportion of mud foam preparation were investigated in this paper.Research results shows that the influence on foam volume is in the descending order of surfactant concentration,stabilizer concentration and mud concentration,while the influence on stable time is in the descending order of mud concentration,stabilizer concentration and surfactant concentration.Meanwhile,the inhibition property of mud foam is measured through the programmed temperature test.The release amount of CO,CH4 of coal samples treat with mud foam at temperature of 200 C decrease by 49.7% and 35.1%,respectively,compare with that of raw coal samples.Hence,the mud foam with good inhibition property can effectively coal oxidation and the release of CO,CH4.
Robotized advance support scheme and optimum support opportunity for deep fully mechanized roadway
Xue Guanghui, Cheng Jijie, Guan Jian, Li Xiuying, Wu Miao
2019, 4(4): 349-356.
Abstract(571) PDF(217)
Abstract:
The fully mechanized excavation working face is the accident-prone area,such as the roof collapse and the rib spailling.With the increase of coal mining depth,the problem becomes more obvious,which seriously threatens the personal safety of coal miners.Advance support is one of the effective ways to prevent accidents and ensure safety.Based on the self-designed robotized self-moving support-anchor combined unit,the advance support scheme of the fully mechanized roadway was proposed,and the struclure and working principle of the support robot were introduced.The concept of optimum support opportunity was proposed.Taking the geological conditions of Qishan mine as an example,the mechanical coupling model of surrounding rock-advance support was established,and the deformation of roadway surrounding rock and the stress of support at different support opportunities were numerically analyzed.The results show that the bearing capacity of surrounding rock is strong with 10~15mm roof subsidence of the roadway,and the maximum roof subsidence reach the lowest of 29.64 mm when it balances,the pressure on the top of advance support reach the lowest of approximately 0.13 MPa,which is good for the design of advance support and safe of the fully mechanized face and is the optimum support opportunity.Finally,this paper summarizes the determination method of the optimal support opportunity of the fully mechanized roadway , which provides ideas for using the surrounding rock self-bearing capacity of roadway,reducing the surrounding rock deformation of roadway,reducing the support cost of roadway,and improving the supporting efficiency and safety of roadway.
Experiment study on fine coal slime flotation with simultaneous ultrasonic treatment
Wang Weidong, Zhang Nan, Jin Lizhang
2019, 4(4): 357-364.
Abstract(596) PDF(123)
Abstract:
In order to investigate the effect of ultrasonic simultaneous treatment on flotation of fine coal slimes,a new ultrasonic flotation device was made to conduct floatation experiment. The particle size distribution of clean coal particles was investigated by SEM.The influence of ultrasound on adsorption of collector was investigated by UV spectrophotometer.The result revealed that combustible recovery and perfect index flotation of floated products increased by using ultrasonic treatment with same reagent dosages.The best flotation effect can be achieved with 100 kH ultrasound , and the combustible recovery rate is 10% higher than that of conventional flotation.Ultrasonic floatation need 19%~35% less reagent dosages than conventional floatation under the same flotation condition.Ultrasonic can remove the fine mud adsorbed on the surface of coal particles , promote bubble agglomeration in the pulp,form air flocculation ,and improve the flotation efficiency of particles with size of +0.045 mm.
Research on debugging condition of vibrating flip-flow screen based on amplitude-frequency characteristics
Yu Chi, Wang Xinwen, Wei Hongbo, Gong Sanpeng, Zhao Guofeng, Zhu Guohui, Sun Jiachuan
2019, 4(4): 365-374.
Abstract(509) PDF(63)
Abstract:
The rationality and stability of the vibrating flip-flow screen have a great influence on its
screening performance and processing capability.In this paper , we established a mechanical model to reflect itsvibration characteristics based on the theory ofdouble - body damping linear vibration. Through mathematical and dynamic analysis , the main dynamic paramelers such as ; damping ratiogg,eccentricily mass moment M,, shear stiffness ha,,and mass ratio pu (mass ratio of floating screen frame and main screen frame) on the amplitude-frequency characteristics of the operating point are verified through tests.The results show that the damping ratio has negligible influence on the relative amplitude in the frequency domain , and the mass ratio u~0.3 is appropriate , which could not increase the mass of the vibrating flip-flow screen, but also reduce the impact of the material on the vibration system.Adjusted shear stiffness could make the working condition in the stable frequency domain; Increasing or decreasing the eccentricity mass moment can increase or decrease the relative amplitude linearly.The method of first regulating u, then adjusting h2, , and finally increasing or decreasing M, is proposed to ensure that the industrial flip-flow screen is located in a stable frequency domain when a reasonable relative amplitude is achieved.This improves the theoretical and technical support of the vibrating flip-flow screen.

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