Study on Strata Behaviors of the Coal Face with Sublevel Caving in Hugely-Thick Coal Seam in Qianqiu Coal Mine

2013 ◽  
Vol 671-674 ◽  
pp. 1150-1155
Author(s):  
Xin Xian Zhai ◽  
Yan Wei Zhai ◽  
Shi Wei Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
High Efficiency ◽  
Production Model ◽  
Practical Significance ◽  
Coal Face ◽  
Thick Coal Seam ◽  
Observation Methods ◽  
Sublevel Caving ◽  
Safety Production

Qianqiu Coal Mine, Yima Coal Group Company Limited, China, has been mining the gently-inclined and hugely-thick coal seam #2-3. The overburden above the coal seam has hugely-thick conglomerate strata with more than 400m thickness, which has significant effects on the strata behaviors of the coal face with sublevel caving. Therefore, study on strata behaviors has an important practical significance to surrounding rocks control and safety production at the coal face. Using theoretical analysis and field observation methods, the following conclusions can be drawn: (1) the surrounding rocks of the coal face with sublevel caving belongs to difficult control one, i.e., it is the surrounding rocks control of roof and floor at the coal face that is difficult. At last, hydraulic supports with sublevel caving of pattern ZF7000-18/28 and their reasonable matching equipment were chosen. (2) The law of strata behaviors of the coal face was observed. Strata behaviors of the coal face were significant and inconsistent at different coal face zones. The parameters of roof weighting interval and roof weighting strength at the coal face were obtained. The maximum value of supporting resistance during periodical weighting was 4307.70kN, being 61.54% of supports rating resistance. Therefore, the supports at the coal face had a higher reliability. Mine production-model with one-mine and one-face can be realized, which promotes the construction of a modernization mine with high production and high efficiency.

scholarly journals Application of Comprehensive Geophysical Prospecting Method in Water Accumulation Exploration of Multilayer Goaf in Integrated Mine

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Lei Zhang ◽  
Lin Xu ◽  
Yong Xiao ◽  
NingBo Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Comprehensive Analysis ◽  
High Density ◽  
Electromagnetic Method ◽  
Mine Safety ◽  
Practical Significance ◽  
Time Base ◽  
Transient Electromagnetic Method ◽  
Transient Electromagnetic

A coal mine in Datong is an integrated mine. At present, there is goaf in the upper and lower part of the mining coal seam. There is a lot of ponding in the goaf, which has great potential safety hazards for production. In order to find out the scope and location of ponding in goaf, the comprehensive geophysical exploration method combining transient electromagnetic method and high-density resistivity method is used to carry out the research. Firstly, the time-base, turn-off time, receiving delay, current, superposition times, and other parameters of the instrument are tested on the surface of known goaf to obtain the best instrument parameters, and the parameters are used to verify the feasibility of the research scheme; then, the transient electromagnetic method is used for large-area exploration on the surface of the mine, the suspected goaf ponding area is found through comprehensive analysis, and the high-density resistivity exploration is arranged in the suspected goaf ponding area. According to the obtained results, the scope and location of the goaf ponding area are accurately located through comprehensive analysis. The results show that there are two goaf ponding areas in the exploration area, which are located above the 8# coal seam currently mined; the range and location of goaf ponding area can be accurately obtained by using the comprehensive geophysical method of high-density electrical method and transient electromagnetic method. This method can provide reference for mine water prevention and control in Datong area and has great practical significance to ensure coal mine safety production.

scholarly journals Study on Roof-Coal Caving Characteristics with Complicated Structure by Fully Mechanized Caving Mining

2019 ◽  
Vol 2019 ◽  
pp. 1-20 ◽  
Author(s):  
Yunpei Liang ◽  
Lei Li ◽  
Xuelong Li ◽  
Kequan Wang ◽  
Jinhua Chen ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Research Work ◽  
Maximum Principal Stress ◽  
Complicated Structure ◽  
Mining Technology ◽  
Thick Coal Seam ◽  
Soft Coal ◽  
Mining Depth ◽  
Arch Forms

With mining technology and mechanization degree being improving, fully mechanized caving mining technology (FCM) has become a main method for thick coal seam extraction in China. However, roof-coal caving characteristics in turn restrict its recovery efficiency, especially for the coal seam with complicated structure (CCS), that is, the coal seam comprises hard or soft coal and gangue. In order to explore the key factors influencing the roof-coal caving and recovery characteristics, related research work has been conducted as follows: firstly, a mechanical model of CCS has been established, which indicates the strength of the coal and gangue will directly affect the roof-coal recovery. Meanwhile, based on the geological settings of Qinyuan coal mine, numerical simulation on roof-coal caving law under different thicknesses of hard or soft coal and gangue has been performed using UDEC software. The results show that the maximum principal stress will increase with the increase of mining depth, making the roof-coal to break easily. Furthermore, the range of the plastic zone of the top coal and the damage degree of the top coal increase with the increase of mining depth. Physical modeling results show that when an extraction-caving ratio is 1, the number of times the coal arch forms is 0.43 at every caving, up to a maximum of 3; the number of times coal arch forms with an extraction-caving ratio of 2 is 4.65 times larger than that with an extraction-caving ratio of 1. The probability of coal arch formation with an extraction-caving ratio of 3 is minimal, about 0.4, which is due to that the arch span is large and the curvature is small, so it is difficult to form a stable arch structure. According to the mechanical characteristics of roof-coal in Qinyuan coal mine, deep-hole blasting technique has been used to reduce the fragments of roof-coal crushed. The results show that this technique can effectively improve the recovery of roof-coal.

scholarly journals Determination of cyclic filling length in gob-side entry retained with roadside filling and its application

2020 ◽  
Author(s):  
Zizheng Zhang ◽  
Jianbiao Bai ◽  
Xianyang Yu ◽  
Weijian Yu ◽  
Min Deng ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Difference Method ◽  
Suggested Method ◽  
Stress Difference ◽  
Thick Coal Seam ◽  
Mechanics Model ◽  
Working Face ◽  
Geological Conditions ◽  
The Relationship

Abstract Gob-side entry retained with roadside filling (GER-RF) plays a key role in achieving coal mining without pillar and improving the coal resource recovery rate. Since there are few reports on the cyclic filling length of GER-RF, a method based on the stress difference method is proposed to determine the cyclic filling length of GER-RF. Firstly, a stability analysis mechanics model of the immediate roof above roadside filling area in GER was established, then the relationship between the roof stress distribution and the unsupported roof length was obtained by the stress difference method. According to the roof stability above roadside filling area based on the relationship between the roof stress and its tensile strength, the maximum unsupported roof length and rational cyclic filling length of GER-RF. Combined with the geological conditions of the 1103 thin coal seam working face of Heilong Coal Mine and the geological conditions of the 1301 thick coal seam working face of Licun Coal Mine, this suggested method was applied to determine that the rational cyclic filling lengths of GER-RF were 2.4 m and 3.2 m, respectively. Field trial tests show that the suggested method can effectively control the surrounding rock deformation along with rational road-in support and roadside support, and improve the filling and construction speed.

scholarly journals Simulation Study of the Roof Fracture Pattern of a Horizontal Sublevel Caving in a Steeply Inclined Thick Coal Seam

2020 ◽  
Vol 2020 ◽  
pp. 1-10
Author(s):  
Xin Kang ◽  
Sheng-li Yang ◽  
Ping Zhan ◽  
Liang-hui Li
Keyword(s):  
Coal Seam ◽  
Fracture Pattern ◽  
Tensile Failure ◽  
Experimental Simulation ◽  
Mining Equipment ◽  
Horizontal Section ◽  
Thick Coal Seam ◽  
Toppling Failure ◽  
Sublevel Caving ◽  
Simulation Results

Application of a horizontal section top-coal caving in a steeply inclined thick coal seam not only effectively resolves the problem of the large dip angle of the coal seam and slipping and dumping of mining equipment but also significantly reduces the tunnel drivage ratio and improves the extraction yield. In addition, it allows for a safe and efficient mining from a steeply inclined thick coal seam. In this paper, the roof fracture pattern of a steeply inclined thick coal seam has been studied by a similar simulation experiment. The results of the simulation are consistent with those of the numerical calculations, thus verifying the accuracy of the simulation. The experimental simulation results show that the roof can form a step-like toppling failure pattern after drawing the coal, and it is difficult to release a triangular coal mass near the floor, which is the main concentration area of coal loss. The numerical simulation results show that, with the excavation of the coal seam, the rock mass around the goaf produces plastic failure, and the damage is mainly concentrated in the roof area. The upper part of the goaf mainly shows a tensile failure, while the other areas mainly show yield failure.

A Coal Mine Hydraulic Support Design and Type Selection of Medium Thick Coal Seam

2014 ◽  
Vol 633-634 ◽  
pp. 1128-1132
Author(s):  
Li Rong Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Simulation Method ◽  
Bottom Plate ◽  
Mining Equipment ◽  
Hydraulic Support ◽  
Support Design ◽  
Thick Coal Seam ◽  
Technical Parameters ◽  
Selection Of

Design and selection of hydraulic support is the core of coal mine fully mechanized mining equipment selection and matching, determine the hydraulic supporting strength Using the numerical simulation method and shallow buried depth of roof structure of theoretical calculation method, determines the necessary technical parameters such as the support frame, the bracket height and the bottom plate pressure According to the coal seam thickness and coal seam structure, which has the instructive meaning in application.

Coal Seam Group Protection Layer Face Causes and Characteristics Analysis of Dynamic Phenomenon

2012 ◽  
Vol 550-553 ◽  
pp. 502-505
Author(s):  
Yong Jiang Zhang ◽  
Xian Zheng Meng ◽  
Zun Yu Xu
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Protective Layer ◽  
Test Area ◽  
Mine Safety ◽  
Dynamic Phenomenon ◽  
Geological Conditions ◽  
Characteristics Analysis ◽  
Safety Production ◽  
Mining Face

In Xinji Coal Mine under complicated geological conditions, regional faults. Experimental zone for near coal seam group mining(6-1,7-1,7-2,8 seam), The objective conditions with protective layer . The minefield of soft broken coal seam, Soft layered coal firmness coefficient f = 0.18. In the test area of 210601,210603 6-1seam protective layer mining face during the period, there were 8 abnormal gas dynamic phenomenon, To the coal mine safety production brought hidden trouble. On the basis of dynamic phenomenon occurring phenomenon, analysis of the dynamic phenomena, combined with the test area actual situation, summed up the6-1coal power causes, for guiding the 6-1safety mining and provide a theoretical basis, has important significance.

scholarly journals Investigation on coal seam distribution and gas occurrence law in Guizhou, China

2018 ◽  
Vol 36 (5) ◽  
pp. 1310-1334 ◽  
Author(s):  
Qingsong Li ◽  
Xin He ◽  
Jiahao Wu ◽  
Shu Ma
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Sedimentary Environment ◽  
Influence Factors ◽  
Preventive Treatment ◽  
Geological Structure ◽  
Mine Safety ◽  
Gas Content ◽  
Gas Occurrence ◽  
Safety Production

In order to enhance the management level of coal mine safety production and promote the “safe, accurate and efficient” preventive treatments for gas in Guizhou of China, the occurrence and other prominent features of coal and gas are investigated. The characteristics and regularities of coal mine accidents in Guizhou during 2001–2015 are summarized to analyze the commonness of gas accidents in general and determine the characteristics of gas preventive treatment. Geological data, gas basic parameters, and physical properties of coal of 386 mines and 761 sets of coal seams in Guizhou are also statistically analyzed. Based on step control theory of gas occurrence structure and the regionally tectonic regularity of coal-bearing stratum distribution, the deformations of coal measures in Guizhou mine area are mainly caused by great variation of stratigraphic occurrence, complicated geological structure, and high crustal stress. The regional occurrence of coal seam is obvious with the highest content of Tongzi–Zunyi–Liuzhi–Xingyi line, which gradually reduces to the both east and west sides. Influence factors and weights of gas occurrence are expounded from geological and coal factor by mathematical statistics, and the main influence factors of gas occurrence are the sedimentary environment, syncline structure, and metamorphic grade in proper sequence. Combined with the risk prediction of coal and gas outburst area, the prediction of gas pressure by gas content is not suitable under the special occurrence conditions. The initial velocity of gas emission, the solidity coefficient, and the damage type in more than 77% of minable seams all exceed the critical value. This work provides guidance in improvement of the governance situation for gas control in Guizhou. The index prediction system which is suitable for mining conditions of special coal mines in Guizhou should be established.

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