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Chinese Mining Practices and Solutions
 
 
Strata Behavior Monitoring of the Sub-Inclination Fully Mechanized Top-Caving Face in Steeply Dipping Extra Thick Coal Seam
35th International Conference on Ground Control in Mining
Strata Behavior Monitoring of the Sub-Inclination Fully Mechanized Top-Caving Face in Steeply Dipping Extra Thick Coal Seam
by
Dongfeng Yun, School of Energy, Xi’an University of Science and Technology, Xi’an 710054, China, Xi‘an, ChinaZhu LiuWendong Cheng, School of Energy, Xi’an University of Science and Technology, Xi’an 710054, China, Xi'an, ChinaZhendong Fan, Huating Coal Group Co. Ltd, Huating, ChinaDongfang Wang, Dongxia Coal Mine, Huating Coal Group Co. Ltd, Heating, ChinaYuanhao Zhang, School of Energy, Xi’an University of Science and Technology, Xi’an 710054, China, Xi‘an, China
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[Conference] 35th International Conference on Ground Control in Mining
[Price] Free  [Comments] 0
[Topical Area] Chinese Mining Practices and Solutions
[Author] Dongfeng Yun, School of Energy, Xi’an University of Science and Technology, Xi’an 710054, China, Xi‘an, ChinaZhu LiuWendong Cheng, School of Energy, Xi’an University of Science and Technology, Xi’an 710054, China, Xi'an, ChinaZhendong Fan, Huating Coal Group Co. Ltd, Huating, ChinaDongfang Wang, Dongxia Coal Mine, Huating Coal Group Co. Ltd, Heating, ChinaYuanhao Zhang, School of Energy, Xi’an University of Science and Technology, Xi’an 710054, China, Xi‘an, China
[Abstract] 
Key Conclusions:
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The results show that the strata pressure of Panel 37220-1 changes slightly along strike, while along dip direction are strong to weak from bottom to top. The initial weighting interval of Panel 37220-2 is about 60.8m, and the average periodic weighting interval is about 22.6m. The Panel 37220-2 strata behavior presents spatio-temporal characteristics, the sequence of periodic weighting is the upper, middle and higher, arc segment, and lower part. During the periodic weighting, the weighting interval and strength are of subarea characteristics. The setting pressure and yield pressure of powered supports is reasonable, could meet the requirement of roof control. The two-leg shield is superior to four-leg chock-shield in steeply dipping coal seam. The open-off cut layout in different planes has an excellent effect on contributes to anti-toppling and anti-skidding of the powered support in the middle and upper section of the face along the dip direction and enhancing the stability of the supporting system.
Key Findings:
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Along the dip direction the location of roof periodic breaking begins in sequence at the middle and upper sections, followed by the upper section and finally the lower section. The ground pressure exhibits in section form also. The yielding of powered support during periodic weighting occurred in sequence most in the upper section, followed by the higher section, and finally the lower section. Hydraulic leg pressure of supports in Panel 37220, vanishing during support advance, does not allow sliding advance. So the support operator should“lower slightly but quickly pull the support forward”with contact advance. The maximum later load of side plate is 20-25MPa, the side plate being a Φ100mm cylinder jack can basically adjust the support effectively.
Objective of the Paper:
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For the purpose of study on the strata behavior of sub-inclination longwall-along-the-strike fully mechanized top-caving face in steeply dipping extra thick coal seam, the upper and lower sub-inclination faces powered support resistance of Panel 37220 in Dongxia coal mine has been measured by on-line and real-time monitoring using KJ513 dynamic monitoring system.
Problem Statement:
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The primary mineable coal seam in Panel 37220 of Dongxia coal mine has the characteristics of steeply dipping (55°~74°), extra thick (19.6m), easily combustible (the spontaneous combustion period is 37d), and complicated parting structure. Panel 37220 adopts the fully-mechanized-top-coal-caving-sub-inclination-along-strike longwall mining method. The open-off cut layout for Panel 37220 adopts the “horizontal line -arc segment- inclined line” in different planes and uses different type of powered supports.