Mechanism and Application of Hydraulic Fracturing in the High-Level Thick and Hard Gangue Layer to Improve Top Coal Caving in Fully Mechanized Caving Mining of an Ultra-Thick Coal Seam
The thick and hard gangue layer has long been one of the key obstacles affecting the coal recovery rate in the fully mechanized top-coal caving mining of ultra-thick coal seams, and it is also one key factor restricting the development of the technology used for such work. In this study, to improve...
| Main Authors: | , , , , , , , |
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| Format: | Article |
| Language: | English |
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MDPI AG
2022-12-01
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| Series: | Minerals |
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| Online Access: | https://www.mdpi.com/2075-163X/12/12/1605 |
| _version_ | 1797456188123643904 |
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| author | Hongye Luo Shun Liang Qiangling Yao Yisong Hao Xuehua Li Furong Wang Xiaoyu Chen Miao Yang |
| author_facet | Hongye Luo Shun Liang Qiangling Yao Yisong Hao Xuehua Li Furong Wang Xiaoyu Chen Miao Yang |
| author_sort | Hongye Luo |
| collection | DOAJ |
| description | The thick and hard gangue layer has long been one of the key obstacles affecting the coal recovery rate in the fully mechanized top-coal caving mining of ultra-thick coal seams, and it is also one key factor restricting the development of the technology used for such work. In this study, to improve the poor top coal cavability and low recovery rate in fully mechanized caving mining of ultra-thick coal seams containing thick and hard gangue layers, the fully mechanized caving mining of longwall working face 42,108 of the Qinggangping Coal Mine is the engineering setting. Then, through a combination of theoretical analysis, numerical simulation, and field practice, a mechanical model of the cantilever beam with uniform load for fracture of the gangue layer is developed. Next, the mechanical action mechanism and influence of the gangue layer and thickness on the fracture of the cantilever beam are analyzed, and a method of pre-fracturing and weakening high-level thick and hard gangue layers using hydraulic fracturing technology is proposed. Finally, using RFPA2D-flow numerical simulation, the key technical parameters of hydraulic fracturing in the working face are designed and applied to field practice. The results show the following: After the high-level thick and hard gangue layer is treated by hydraulic fracturing technology, the amount of fractured gangue behind the support increases, while that of big coal blocks decreases significantly, and the overall fragmentation of top coal is at a reasonable level. In addition, after taking hydraulic fracturing technical measures during the mining period of the working face, the average recovery rate of the working face is 86.6%. This is an increase of 6.5% over the previous area without hydraulic fracturing. |
| first_indexed | 2024-03-09T16:03:44Z |
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| id | doaj.art-f5a61283c63b4e39b1d87f087ea2595f |
| institution | Directory Open Access Journal |
| issn | 2075-163X |
| language | English |
| last_indexed | 2024-03-09T16:03:44Z |
| publishDate | 2022-12-01 |
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| record_format | Article |
| series | Minerals |
| spelling | doaj.art-f5a61283c63b4e39b1d87f087ea2595f2023-11-24T16:52:37ZengMDPI AGMinerals2075-163X2022-12-011212160510.3390/min12121605Mechanism and Application of Hydraulic Fracturing in the High-Level Thick and Hard Gangue Layer to Improve Top Coal Caving in Fully Mechanized Caving Mining of an Ultra-Thick Coal SeamHongye Luo0Shun Liang1Qiangling Yao2Yisong Hao3Xuehua Li4Furong Wang5Xiaoyu Chen6Miao Yang7Key Laboratory of Deep Coal Resource Mining, Ministry of Education, School of Mines, China University of Mining and Technology, Xuzhou 221008, ChinaKey Laboratory of Deep Coal Resource Mining, Ministry of Education, School of Mines, China University of Mining and Technology, Xuzhou 221008, ChinaKey Laboratory of Deep Coal Resource Mining, Ministry of Education, School of Mines, China University of Mining and Technology, Xuzhou 221008, ChinaKey Laboratory of Deep Coal Resource Mining, Ministry of Education, School of Mines, China University of Mining and Technology, Xuzhou 221008, ChinaKey Laboratory of Deep Coal Resource Mining, Ministry of Education, School of Mines, China University of Mining and Technology, Xuzhou 221008, ChinaKey Laboratory of Deep Coal Resource Mining, Ministry of Education, School of Mines, China University of Mining and Technology, Xuzhou 221008, ChinaKey Laboratory of Deep Coal Resource Mining, Ministry of Education, School of Mines, China University of Mining and Technology, Xuzhou 221008, ChinaKey Laboratory of Deep Coal Resource Mining, Ministry of Education, School of Mines, China University of Mining and Technology, Xuzhou 221008, ChinaThe thick and hard gangue layer has long been one of the key obstacles affecting the coal recovery rate in the fully mechanized top-coal caving mining of ultra-thick coal seams, and it is also one key factor restricting the development of the technology used for such work. In this study, to improve the poor top coal cavability and low recovery rate in fully mechanized caving mining of ultra-thick coal seams containing thick and hard gangue layers, the fully mechanized caving mining of longwall working face 42,108 of the Qinggangping Coal Mine is the engineering setting. Then, through a combination of theoretical analysis, numerical simulation, and field practice, a mechanical model of the cantilever beam with uniform load for fracture of the gangue layer is developed. Next, the mechanical action mechanism and influence of the gangue layer and thickness on the fracture of the cantilever beam are analyzed, and a method of pre-fracturing and weakening high-level thick and hard gangue layers using hydraulic fracturing technology is proposed. Finally, using RFPA2D-flow numerical simulation, the key technical parameters of hydraulic fracturing in the working face are designed and applied to field practice. The results show the following: After the high-level thick and hard gangue layer is treated by hydraulic fracturing technology, the amount of fractured gangue behind the support increases, while that of big coal blocks decreases significantly, and the overall fragmentation of top coal is at a reasonable level. In addition, after taking hydraulic fracturing technical measures during the mining period of the working face, the average recovery rate of the working face is 86.6%. This is an increase of 6.5% over the previous area without hydraulic fracturing.https://www.mdpi.com/2075-163X/12/12/1605high-level gangue layerfully mechanized caving mininghydraulic fracturingrecovery rate |
| spellingShingle | Hongye Luo Shun Liang Qiangling Yao Yisong Hao Xuehua Li Furong Wang Xiaoyu Chen Miao Yang Mechanism and Application of Hydraulic Fracturing in the High-Level Thick and Hard Gangue Layer to Improve Top Coal Caving in Fully Mechanized Caving Mining of an Ultra-Thick Coal Seam Minerals high-level gangue layer fully mechanized caving mining hydraulic fracturing recovery rate |
| title | Mechanism and Application of Hydraulic Fracturing in the High-Level Thick and Hard Gangue Layer to Improve Top Coal Caving in Fully Mechanized Caving Mining of an Ultra-Thick Coal Seam |
| title_full | Mechanism and Application of Hydraulic Fracturing in the High-Level Thick and Hard Gangue Layer to Improve Top Coal Caving in Fully Mechanized Caving Mining of an Ultra-Thick Coal Seam |
| title_fullStr | Mechanism and Application of Hydraulic Fracturing in the High-Level Thick and Hard Gangue Layer to Improve Top Coal Caving in Fully Mechanized Caving Mining of an Ultra-Thick Coal Seam |
| title_full_unstemmed | Mechanism and Application of Hydraulic Fracturing in the High-Level Thick and Hard Gangue Layer to Improve Top Coal Caving in Fully Mechanized Caving Mining of an Ultra-Thick Coal Seam |
| title_short | Mechanism and Application of Hydraulic Fracturing in the High-Level Thick and Hard Gangue Layer to Improve Top Coal Caving in Fully Mechanized Caving Mining of an Ultra-Thick Coal Seam |
| title_sort | mechanism and application of hydraulic fracturing in the high level thick and hard gangue layer to improve top coal caving in fully mechanized caving mining of an ultra thick coal seam |
| topic | high-level gangue layer fully mechanized caving mining hydraulic fracturing recovery rate |
| url | https://www.mdpi.com/2075-163X/12/12/1605 |
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