A New Gob-Side Entry Layout for Longwall Top Coal Caving

Guorui Feng, Pengfei Wang and Yoginder P. Chugh
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Guorui Feng: College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, China
Pengfei Wang: College of Mining Engineering, Taiyuan University of Technology, Taiyuan 030024, China
Yoginder P. Chugh: Mining and Mineral Resources Engineering, Southern Illinois University, Carbondale, IL 62901, USA

Energies, 2018, vol. 11, issue 5, 1-24

Abstract: In China, gob-side entry is typically located one pillar-width (less than 5 m) away from the previously mined-out panel in a conventional longwall panel using top coal caving (LTCC). Design of gob-side entries is a challenge due to the complex dynamic loading process during their service life. A new gob-side entry (NGE) design practice is presented here for Zhenchengdi Colliery, which has many advantages. A theoretical analysis is presented followed by numerical modeling. The modeling included the double-yield constitutive model for gob behavior to analyze the stress environment for the gob-side entry with validation through field observations. The results indicate that pre-mining stress within gob occurred 51 m away from the gob edge. The NGE is located within a destressed zone in the entire panel system, which results in lower side abutment pressure for the adjacent panel to be mined. The stress concentration around the gob edge near the gob-side entry is relatively low (less than 0.1) compared with the other side of the gob. Field observations indicate that: (1) a simple support design, i.e., steel sets with wire mesh on the top, can maintain ground control and ventilation during active mining; (2) the periodic weighting interval is 9–12 m; (3) the length of the block “B” which “protects” the gob-side entry is 10–13 m; (4) stress distribution formula for the elevating section is derived; and (5) the roof pressure of the gob-side entry is much smaller than non-gob side entry and is smaller than the pre-mining stress. Deformation data of the gob-side entry shows that both roof-to-floor and rib-to-rib convergences are smaller than for the non-gob-side entry with an improved overall stress environment. Theoretical analysis, numerical modeling, and field observation are consistent, which validates the scientific foundations of the new technology.

Keywords: gob-side entry; angle of break; double-yield model; panel geometry (search for similar items in EconPapers)
JEL-codes: Q Q0 Q4 Q40 Q41 Q42 Q43 Q47 Q48 Q49 (search for similar items in EconPapers)
Date: 2018
References: View complete reference list from CitEc
Citations: View citations in EconPapers (4)

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