Extraction of Pressurized Gas in Low Air-Conductivity Coal Seam Using Drainage Roadway

Li, Shugang; Shuang, Haiqing; Wang, Hongsheng; Song, Ki-Il

doi:10.3390/su9020223

Cited by 8 publications

(6 citation statements)

References 10 publications

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“…Former research has shown that a rock drainage roadway and high-level directional extraction borehole can effectively extract gas in the fissure zone and have great operational stability in the upper corner of the goaf and return air flow [10][11][12][13]. However, the rock drainage roadway has the disadvantage of requiring a large amount of site construction, long operation cycles, and high costs [14][15][16]. With improved equipment, the high-level directional extraction borehole can replace the high-level drainage roadway to extract gas in the goaf and fissure cycles, and high costs [14][15][16].…”

Section: Introductionmentioning

confidence: 99%

Study and Application of High-Level Directional Extraction Borehole Based on Mining Fracture Evolution Law of Overburden Strata

Zhang

Wang²,

Wang³

2023

Sustainability

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The technical principle of gas drainage using high-level directional extraction boreholes was analyzed. A range of overburden strata was stimulated for pressure relief during mining, the effects of different borehole parameters on gas flow in the goaf and gas concentration in the upper corner were compared, and a field test was conducted to analyze the effect and peculiarities of gas drainage. With the mining of the work plane, overburden mining fissures gradually develop forward and upward, showing a “saddle” shape along the coal seam. The fissures in the middle zone of the goaf are gradually compacted, and a gas accumulation zone is formed around the goaf. High-level directional extraction boreholes arranged in an ellipsoidal belt at the side of the air return can achieve efficient gas extraction in the roof fissure belt. Numerical simulation results showed that the height of the fully depressurized area was 65 m from the roof of the coal seam. In addition, three high-level directional extraction boreholes were drilled in the roof of the coal seam. The gas extraction concentration and gas extraction pure volume of these three boreholes first increased, then decreased, and finally tended to be stable. The sequence of their average values was borehole No.2 > No.3 (twice as much) and > No.1 (2.7 times as much), which are closely related to the evolution law of overburden mining fissures. The research results can provide a reference for the further study of gas extraction technology using high-level directional extraction boreholes in coal and gas outburst seams.

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Section: Introductionmentioning

confidence: 99%

Study and Application of High-Level Directional Extraction Borehole Based on Mining Fracture Evolution Law of Overburden Strata

Zhang

Wang²,

Wang³

2023

Sustainability

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“…Some scholars studied the gas extraction method (e.g., high-level boreholes extraction and high drainage roadway extraction) in the mine-out areas after mining [22,23]. Among them, high-level boreholes extraction is an efficient gas extraction method to control gas over the limit.…”

Section: Introductionmentioning

confidence: 99%

Application and Optimization of the Parameters of the High-Level Boreholes in Lateral High Drainage Roadway

et al. 2022

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The key parameters of high-level boreholes in high drainage roadways affect the gas treatment effect of the working face directly. Therefore, the layout parameters of high-level boreholes in the lateral high drainage roadway (LHDR) are determined and optimized as necessary. Based on the LHDR layout on the 2-603 working face of the Liyazhuang coal mine, the key technological requirements on high-level borehole parameters were analyzed and the distribution characteristics of the gas volume fraction in the coal roof were studied. The gas migration law in the mined-out areas was obtained and the layout locations of high-level boreholes were determined finally. The research demonstrates that the high-level boreholes lag the 2-603 working face distance and the position of the final borehole (the position of the final borehole in this paper refers to the distance between the final borehole and the roof) influence the stability of boreholes and the gas extraction effect. The distribution of the gas volume fraction from the intake airway to the return airway can be divided into the stable stage, slow growth stage, and fast growth stage. Influenced by the flow field in the mined-out areas, the mean volume fraction of the borehole-extracted gas has no obvious relationship with the gas volume fraction at the upper corner. According to the final optimization, the high-level borehole is determined as having a 15 m lag behind the working face and the position of the final borehole is 44 m away from the coal seam roof. These have been applied successfully in engineering practice.

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“…At present, the research results of the distribution and evolution characteristics of the floor rock layer in the upper coal seam working face are mainly based on the finite element numerical calculation and similar material simulation experiments and lack of theoretical research on the floor rock mass movement. At the same time, the floor stress field monitoring research has the characteristics of difficult testing and high cost, and the research progress is slow [15][16][17][18][19][20]. In addition, a large number of domestic and foreign scholars have made a lot of research results on the influence of floor level and gas layer [21][22][23][24][25][26].…”

Section: Introductionmentioning

confidence: 99%

Research on the Evolution Characteristics of Floor Stress and Reasonable Layout of Roadways in Deep Coal Mining

Zhang

et al. 2021

Geofluids

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The safe and efficient mining of deep coal resources is severely restricted by the dynamic disasters caused by high gas and high ground stress. Taking a deep mine in China as the research background, a mechanical model of the front supporting stress with the working face was constructed through theoretical calculations. Based on the limit equilibrium theory, the stress distribution in the plastic zone and the elastic zone of the lateral working face was derived; based on semi-infinite plane mechanics model, the floor vertical and horizontal stress distribution was deduced. Then, the roadway surrounding rock stress and displacement field distribution evolution characteristics were revealed through numerical simulation. On this basis, the reasonable floor gas drainage roadway (FGDR) layout was determined: internal staggered layout was used with FGDR, the vertical distance to the working face is 20 m, and the horizontal distance to the working face end is 15 m; the open-off cut of FGDR was arranged in an external staggered layout, the vertical distance to the working face is 20 m, and the horizontal distance to the open-off cut of the working face is 15 m. It is an important practical significance for the layout of FGDR, the control of surrounding rocks, and the improvement of gas drainage effects under similar conditions through the research results.

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Extraction of Pressurized Gas in Low Air-Conductivity Coal Seam Using Drainage Roadway

Cited by 8 publications

References 10 publications

Study and Application of High-Level Directional Extraction Borehole Based on Mining Fracture Evolution Law of Overburden Strata

Study and Application of High-Level Directional Extraction Borehole Based on Mining Fracture Evolution Law of Overburden Strata

Application and Optimization of the Parameters of the High-Level Boreholes in Lateral High Drainage Roadway

Research on the Evolution Characteristics of Floor Stress and Reasonable Layout of Roadways in Deep Coal Mining

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