Accident Analysis and Prevention Measure of Dynamic Load Mine Pressure of the 31201 Fully Mechanized Working Face of Shigetai Coal Mine

Abstract The high stress of the surrounding rock of Hexi Coal Mine easily leads to severe deformation of the retracement channel and the appearance of the mine pressure during the retreat severely affects the stability of the roadway. In order to solve the above problems, a roadway surrounding rock control technology is proposed and tested. The bidirectional energy-concentrated tensile blasting technology is used to perform directional cutting to cut off the stress propagation path. Firstly, the deformation mechanism of the roof is analyzed by establishing the deformation mechanical model of the roof of the retracement channel. Then, according to the geological conditions of working face 3314 and theoretical calculation, the key parameters of roof cutting and pressure releasing of retracement channel are determined, and through the numerical analysis of its cutting effect, the length of cutting seam is 11.5m, and the cutting angle is 10°. Finally, a field test is carried out on the retracement channel of 3314 working face to verify the effect of roof cutting. The results show that the deformation of the retracement channel and the main roadway is very small. In the process of connecting the working face and the retracement channel, the maximum roof to floor convergence is 141mm, and the two sides convergence is 79mm. After the hydraulic support was retracted, the maximum roof to floor convergence of the surrounding rock is 37 mm, and the two sides convergence is 33mm. The roof cutting and pressure releasing of the retracement channel ensures the safe evacuation of the equipment and the stability of the main roadway. The cutting effect is obvious for the release of pressure, which is of great significance to engineering practice.

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

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.256-259.1443 ◽

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.

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Coal Burst Induced by Horizontal Section Mining of a Steeply Inclined, Extra-Thick Coal Seam and Its Prevention: A Case Study from Yaojie No. 3 Coal Mine, China

Shock and Vibration ◽

10.1155/2019/8469019 ◽

2019 ◽

Vol 2019 ◽

pp. 1-13 ◽

Cited By ~ 8

Author(s):

Zhengyi Wang ◽

Linming Dou ◽

Guifeng Wang

Keyword(s):

Coal Mine ◽

Dynamic Load ◽

Abutment Pressure ◽

Static Load ◽

Horizontal Section ◽

Static Loads ◽

Thick Coal Seam ◽

Working Face ◽

Limiting Load ◽

Coal Bursts

At present, coal bursts in working faces of steeply inclined coal seams (SICSs) have rarely been investigated, and current research focuses on the influences of roof breaking and instability of overlying structures in goaf on coal bursts; however, the stress state of coal masses in working faces being subjected to coal bursts is rarely researched. To overcome the above defects, a model for analysing stresses on coal masses in horizontal section of SICSs was established based on the coal burst that occurred in LW5521-20, Yaojie No. 3 Coal Mine, Lanzhou, Gansu Province, China. Moreover, the mechanism underpinning such a coal burst in SICSs was analysed based on the superposition mechanism of dynamic and static loads. The results show that the side abutment pressure near the roof and floor under the horizontal sections of SICSs is asymmetrically distributed in the vertical direction in which the peak of side abutment pressure near the roof is closer to the working face and therefore is taken as the source of static loads for coal bursts in working faces. When the superimposed dynamic load caused by hanging roof breaking and high static load borne in the coal masses is larger than the critical load for coal burst inception, a coal burst will occur. Furthermore, the superimposed dynamic load induced by coal bursts on the support and the initial static load on the supports are larger than their limiting load, which leads to support collapse and eventually causes dynamic failure of the working face. The coal burst in working faces in horizontal sections of SICSs can be prevented by using deep-hole presplit blasting in a hard roof, destress blasting in coal masses, and support optimisation of working faces, showing a favourable preventative effect.

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Analysis on Instability of Surrounding Rock in Gob-Side Entry Retaining with the Character of Soft Rock Composite Roof

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.524-527.396 ◽

2012 ◽

Vol 524-527 ◽

pp. 396-403 ◽

Cited By ~ 1

Author(s):

De Chuan Yang ◽

Ming Zhong Gao ◽

Yun Hai Cheng ◽

Wu Sheng ◽

Jia Sheng Chen

Keyword(s):

Coal Mine ◽

Soft Rock ◽

Main Roof ◽

Wide Distribution ◽

Economic Security ◽

Surrounding Rock ◽

Mine Pressure ◽

Working Face ◽

Immediate Roof ◽

Plastic Zones

The filling belt of gob-side entry retaining with the character of soft rock composite roof,deforms violently,affected by the fracture and rotation of the main roof,and is prone to instability.This essay,considering characteristecs of coal mine pressure behavior on -790m 1311 (1) working face ventilation roadway at DingJi coal mine in HuaiNan,puts forward structural mech -anics model of the key block of gob-side entry retaining,which is used to forecast the position of the fracture line of the main roof, and analyze the roof subsidence at the side of the filling belt;It applies FLAC and UDEC to simulate distribution of plastic zones of surrounding rock of gob-side entry retaining,and stress variation law of the immediate roof and the main roof along coal seam inclination.The results show that:stress concentration factor of the immediate roof on the filling belt is about 1.6,first decreasing and then increasing with increasing width of the filling belt,which indicates that reasonable width of the filling belt is 3.0 m in accordance with the requirement of economic security requirment. The filling belt has significantly wide distribution of the plastic zones,with its four corners obviously plasticized,and overlying strata above the filling belt at side of goaf suffering upward plasticization,which is the result of rotation of the main roof; Deform- ation instability of filling belt is mainly caused by fracture rotation of the main roof;Finally, the measures to reduce the instability of gob-side entry retaining with the character of soft rock comp- osite roof are put forward.

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Prediction of rockbursts in a typical island working face of a coal mine through microseismic monitoring technology

Tunnelling and Underground Space Technology ◽

10.1016/j.tust.2021.103972 ◽

2021 ◽

Vol 113 ◽

pp. 103972

Author(s):

Chao Zhang ◽

Gaohan Jin ◽

Chao Liu ◽

Shugang Li ◽

Junhua Xue ◽

...

Keyword(s):

Coal Mine ◽

Microseismic Monitoring ◽

Monitoring Technology ◽

Working Face

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One spatial geometric characteristic identification method of a coal mine working face based on ground movement and deformation monitoring data

Energy Sources Part A Recovery Utilization and Environmental Effects ◽

10.1080/15567036.2021.1915436 ◽

2021 ◽

pp. 1-15

Author(s):

Tao Wei ◽

Lei Wang ◽

Kegui Jiang ◽

Yuezong Wang ◽

Xiangsheng Yang

Keyword(s):

Coal Mine ◽

Mine Working ◽

Geometric Characteristic ◽

Deformation Monitoring ◽

Ground Movement ◽

Monitoring Data ◽

Identification Method ◽

Working Face ◽

Movement And Deformation

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Research on Deformation Mechanisms of a High Geostress Soft Rock Roadway and Double-Shell Grouting Technology

Geofluids ◽

10.1155/2021/6215959 ◽

2021 ◽

Vol 2021 ◽

pp. 1-13

Author(s):

Fengnian Wang ◽

Shizhuang Chen ◽

Pan Gao ◽

Zhibiao Guo ◽

Zhigang Tao

Keyword(s):

Mechanical Properties ◽

Rock Mass ◽

Large Deformation ◽

Coal Mine ◽

Soft Rock ◽

In Situ Stress ◽

Deformation Monitoring ◽

Deformation And Failure ◽

Working Face ◽

High Geostress

In this study, the deformation characteristics and mechanical properties of coal and rock mass in the S2N5 working face of the Xiaokang coal mine are analyzed to address the problem of large deformation of soft rocks with high in situ stress surrounding roadways. Through a newly developed grouting pipe, a double-shell grouting technology, consisting of low-pressure grouting and high-pressure split grouting, is proposed for the Xiaokang coal mine. In addition, the effect of grouting is evaluated by borehole peeping and deformation monitoring. The results show that the double-shell grouting technology can effectively improve the overall mechanical properties of the surrounding coal and rock mass, preventing the large deformation and failure of the roadway. This technology can be useful when analyzing and preventing large deformation of soft rock roadways.

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Research and Application of an Innovative 110 Mining Method in Gob-Side Half Coal Rock Entry Retaining

Shock and Vibration ◽

10.1155/2021/8228604 ◽

2021 ◽

Vol 2021 ◽

pp. 1-8

Author(s):

Eryu Wang ◽

Xiangdong Chen ◽

Xiaojie Yang

Keyword(s):

Recovery Rate ◽

Mine Pressure ◽

Mining Method ◽

Time Consumption ◽

Coal Recovery ◽

Working Face ◽

Constant Resistance ◽

Movement Characteristic ◽

Coal Rock ◽

Maximum Subsidence

In order to solve the problems of the high cost and time consumption of half coal rock entry driving, low coal recovery rate, and stress concentration on filling support body of retained entry along gob, the innovative 110 mining method based on pressure relief by roof cutting was adopted in 6302 thin coal seam working face of Baoshan Coal Mine. First the technical principle and key technology of this mining method was presented. Then, through theoretical analysis and calculation, engineering experience, and field test, the key parameters such as the length of constant resistance anchor cable, the cutting angle and height of presplitting blasting, the charge structure, and the blocking-gangue support structure were determined and conducted in the retained entry. The broken expanded coefficient varying law of caved gangue with time and space was obtained, which revealed roof movement characteristic. The displacement monitoring curve of the roof and floor indicated that the maximum subsidence of the roof was about 150 mm and the maximum amount of floor heaving was 100 mm, which were quite small. The field monitoring data indicated that the entry retaining effect is good, which indicated that the innovative 110 mining method can be an effective way for reducing the high cost and time consumption of half coal rock entry driving, enhancing the coal recovery rate and preventing the dynamic mine pressure disasters.

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Characteristics of New Permanent Magnetic Eddy Current Drive System of the Scraper Conveyor

10.21203/rs.3.rs-548513/v1 ◽

2021 ◽

Author(s):

shuang wang ◽

Yongcun GUO ◽

Deyong LI

Keyword(s):

Eddy Current ◽

Coal Mine ◽

Mining Area ◽

Current Drive ◽

Drive System ◽

Model Accuracy ◽

Working Face ◽

Scraper Conveyor ◽

Mining Face ◽

Motion Characteristics

Abstract This study provides a new permanent magnetic eddy current drive system to solve the ener-gy-saving drive problem of the scraper conveyor working under bad conditions, including overload startup, severe abrasion and pollution. Considering the practical conveying conditions of the scraper chain on a fully mechanised coal mining face, this study creates a mathematical model for the new permanent magnetic eddy current drive system of the scraper conveyor based on its characteristics and indicates the motion characteristics of the scraper chain driven by two wheels. This study verifies the model accuracy with a pre-startup technology depending on the scraper conveyor on the No. 12318 working face of the 8th coal mine in the West No. 1 mining area of the Pansan Coal Mine of the Huainan Mining Group. According to the results, the motion acceleration of the scraper chain based on the new permanent magnetic eddy current drive is lower than that of the scraper chain with a hydraulic coupler under the same running condition and load during startup and acceleration and declines by approximately 14.7%. Consequently, this can decline the startup impact due to the serious abrasion and frequent overload of the scraper chain working under bad conditions.

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