Research on Mining Engineering with Dual Gradient High Inclination-Angle Fully Mechanized Mining Technology

2014 ◽  
Vol 977 ◽  
pp. 231-234 ◽  
Author(s):  
Xin Song ◽  
Li Min Wang
Keyword(s):  
Coal Seam ◽  
Inclination Angle ◽  
Coal Mine ◽  
Mining Engineering ◽  
Hydraulic Support ◽  
Mining Technology ◽  
Research Site ◽  
Working Face ◽  
Dual Gradient

In this paper, it will take in-depth research, site practical methods, and provide reasonable solutions to several key problems, such as conveyor and hydraulic support sliding；shearers badly sloped；the roof management of return airway when the working face lengthened；dealing with the upper corner gas；gangue fleeing；turn mining，which seriously affect production during high inclination-angle fully mechanized mining at 3# coal seam of the second mining section of ChengShan coal mine.

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 Reasonable Scope of Kilometer Drilling in Lower Layer of Extrathick Coal Seam: A Case Study of Tingnan Coal Mine, China

2021 ◽  
Vol 2021 ◽  
pp. 1-17
Author(s):  
Delong Zou ◽  
Xiang Zhang
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Lower Layer ◽  
Maximum Depth ◽  
Support Pressure ◽  
Directional Drilling ◽  
Pressure Relief ◽  
Gas Drainage ◽  
Working Face ◽  
Fracture Development

When stratified mining is adopted in high-gas and extrathick coal seam, a large amount of pressure-relief gas of the lower layer flows into the upper layer goaf along the cracks in the layer, resulting in upper layer working face to frequently exceed the gas limit. And ordinary drilling can no longer meet the requirements of the pressure-relief gas drainage of the lower layer. The 205 working face of Tingnan Coal Mine is taken as the test background in this paper, and based on the “pressure-relief and flow-increase” effect of the lower layer under the action of mining stress during the upper layer mining, the gas drainage of kilometer directional drilling in lower layer is studied. According to the distribution characteristics of support pressure before and after the working face, the pressure-relief principle, fracture development characteristics, and gas migration law of the lower layered coal body are analyzed in the process of advancing the upper layered working face in the extrathick coal seam with high gas. The maximum depth of goaf damage is calculated theoretically, and the Flac3D numerical simulation of the failure deformation of the 205 working face floor is carried out. It is found that the maximum depth of plastic failure of the lower layer is about 13 m. According to the plastic deformation of the lower layer under different vertical depths and the movement of coal and rock mass, it is determined that the reasonable range of kilometer directional drilling in the lower layer is 6–9 m below the floor vertical depth. From 15 m to 45 m in the two parallel grooves, there is no fracture failure with a sharp increase or decrease in the displacement in the local range. Meanwhile, in this part, the roof falling behind is not easy to compaction, and the displacement of the floor is large, which does not cause plastic damage. The degree of pressure relief is more sufficient, and the permeability of the lower layer is good. Therefore, drilling should be arranged as much as possible along the working face in this tendency range. The determination of reasonable arrangement range of kilometer directional drilling in extrathick coal seam provides reference index and theoretical guidance for industrial test of working face and also provides new ideas for gas control of stratified mining face in high-gas and extrathick coal seam.

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.

Study on the Relationship between Hydraulic Support on the Working Face with Large Mining Height and Surrounding Rock

2011 ◽  
Vol 328-330 ◽  
pp. 1671-1674
Author(s):  
Ying Ma ◽  
Sheng Zhong
Keyword(s):  
Coal Seam ◽  
Surrounding Rock ◽  
Hydraulic Support ◽  
Working Face ◽  
Safety Work ◽  
Immediate Roof ◽  
The Face ◽  
Large Mining Height ◽  
The Relationship ◽  
Mining Height

Using unified model and theory of rock pressure, the problems, such as caving of stope roof with large mining height and destruction of support, strata movement and surface subsidence, are unified analyzed and researched. The results show that: pressure shell is dynamic shell, which moves forward with the propulsion of working face; with the increase of mining height on the face, the height of fracture zone in coal seam increases, not continuously, but jumpily; with the increase of mining height, support load rises, but the degree of this rise decreases gradually, increased degree of immediate roof weight should be greater than that of given deformation pressure. The results provide necessary basis for reliability of hydraulic support on the working face with large mining height and safety work in the underground.

scholarly journals Application of BigML in the Classification Evaluation of Top Coal Caving

2021 ◽  
Vol 2021 ◽  
pp. 1-28
Author(s):  
Meng Wang ◽  
Caiwang Tai ◽  
Qiaofeng Zhang ◽  
Zongwei Yang ◽  
Jiazheng Li ◽  
...  
Keyword(s):  
Coal Seam ◽  
Coal Mine ◽  
Evaluation Model ◽  
Engineering Practice ◽  
Coal Seams ◽  
Mining Technology ◽  
Evaluation Result ◽  
Sample Data ◽  
Classification Evaluation ◽  
Longwall Top Coal Caving

Longwall top coal caving mining is one of the main methods of mining thick coal seams in China. Therefore, carrying out the classification evaluation of top coal caving is of great significance to ensure mining success and reduce the risk of mining technology. In order to realize the classification evaluation of top coal caving, this article introduces the method of using BigML to establish the classification evaluation model of top coal caving. Furthermore, using the data from the CNKI database as sample data, a classification evaluation model of top coal caving is established on BigML. After training, testing, and optimization, the model is used to evaluate the top coal caving in No. 3 coal seam of Gucheng Coal Mine, and the evaluation result is grade 1, which is consistent with the engineering practice. The final research results show that the application of BigML in the classification evaluation of top coal caving is successful; the evaluation of top coal caving through BigML is reliable; BigML provides another scientific reliability way for the classification evaluation of top coal caving.

Analysis of Weighting over Great Extent upon Fully Mechanized Coal Face with Non-Hard Roof Based on Measured Data

2014 ◽  
Vol 962-965 ◽  
pp. 992-997
Author(s):  
Tao Zhu
Keyword(s):  
Experimental Analysis ◽  
Safety Valve ◽  
Measured Data ◽  
Large Area ◽  
Coal Face ◽  
Hydraulic Support ◽  
Mining Technology ◽  
Hard Roof ◽  
Drawing Speed ◽  
Working Face

Due to the influence of geology, mining technology, supporting strength, fully mechanized coal face sometimes would happen large area caving and weighting over great extent, causing casualties. Theoretical and experimental analysis shows, not only hard roof could happen weighting over great extent, but softer roof upon long wall face could happen, the only difference was the location of disaster and the failure forms. The paper analyzed weighting over great extent upon fully mechanized coal face with non-hard roof based on measured data. The results show that, the important factors of support break-off were the setting load of hydraulic support, drawing speed of working face and support efficiency, and it would achieve support break-off warning help to analyze the open rates of safety valve.

Study on Mine Pressure Behavior of Roadway in Highly Irregular Working Face in Daizhuang Coal Mine

2012 ◽  
Vol 256-259 ◽  
pp. 1443-1446
Author(s):  
Xing Lin Wen ◽  
Lin Hai Gao ◽  
Chuan Lei Li ◽  
Meng Meng Dong
Keyword(s):  
Coal Mine ◽  
Surrounding Rock ◽  
Mine Pressure ◽  
Mining Engineering ◽  
Deformation Characteristics ◽  
Working Face ◽  
Production Safety ◽  
Support Force ◽  
Mining Face ◽  
Important Significance

The irregular face mechanized mining is one of the difficult problems in the field of mining engineering. In this thesis, the roadways of 4324 extremely irregular face in DaiZhuang Mine were taken as research object. Through on-site mine pressure observation, the deformation characteristics of the surrounding rock and support force was analyzed. Next the mine pressure appeared rule of the roadways was study. This study benefited that the production of 4324 mining face went on wheels, at the same time, it had important significance to production safety of irregular working face with similar conditions.

scholarly journals Numerical simulation study on gas drainage by interval hydraulic flushing in coal seam working face

2021 ◽  
pp. 014459872110102
Author(s):  
Shengrong Xie ◽  
Junqi Cui ◽  
Dongdong Chen ◽  
Ping Chen
Keyword(s):  
Numerical Simulation ◽  
Coal Seam ◽  
Coal Mine ◽  
Simulation Software ◽  
Gas Pressure ◽  
Gas Extraction ◽  
Gas Drainage ◽  
Drainage Radius ◽  
Working Face ◽  
Effective Drainage

In order to solve the problem of difficult gas extraction in coal mine, a method of gas extraction from coal seam by interval hydraulic flushing is put forward. Based on the coal seam gas occurrence conditions of 7609 working face in Wuyang Coal Mine, the numerical simulation research on gas drainage by ordinary drilling and hydraulic flushing drilling was carried out by using COMSOL numerical simulation software. The results show that with the increase of hydraulic flushing coal quantity, the effective gas drainage radius also increases. The effective extraction radius of ordinary drilling is 0.5 m, and the effective extraction radius is 1.0 m, 1.2 m and 1.3 m respectively when the coal flushing quantity is 0.5t/m, 1.0t/m and 1.5t/m. As multiple boreholes are drained at the same time, the boreholes will affect each other, which will reduce the gas pressure and increase the effective drainage radius, the spacing between boreholes can be greater than twice the effective drainage radius of a single borehole when arranging boreholes. And the smaller the flushing interval, the more uniform the gas pressure reduction area. According to the numerical simulation results, the ordinary drilling and 1.0t/m interval hydraulic flushing test were carried out in the field. Through observation and analysis, the gas concentration of the interval hydraulic flushing drilling module was increased by 31.2% and the drainage purity was increased by 5.77 times compared with the ordinary drilling module. It shows that the interval hydraulic flushing drilling can effectively improve the gas drainage effect.

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