Stability Mechanism and Control Technology for Fully Mechanized Caving Mining of Steeply Inclined Extra-Thick Seams with
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Stability Mechanism and Control Technology for Fully Mechanized Caving Mining of Steeply Inclined Extra-Thick Seams with Variable Angles Wang Hongwei 1,2,3
&
Wu Yongping 1,2,3 & Jiao Jianqiang 1 & Cao Peipei 4
Received: 31 May 2020 / Accepted: 11 November 2020 # Society for Mining, Metallurgy & Exploration Inc. 2020
Abstract Fully mechanized top caving mining of steeply inclined extra-thick seams with variable angles has complex roof rock movement, failure, caving, and filling mechanisms. Moreover, the variable-angle coal seams make rock–equipment stability control challenging. We analyzed rock deformation and failure mechanisms, overburden bearing structures, and working characteristics of supports through physical simulations, field tests, and theoretical analysis of the no. 120210 working face of Zaoquan Coal Mine. Overburden rock movement has distinct regional characteristics, with a large caving height (to the main roof layer) in the upper area, and lower caving height (to the lower main roof) in the lower area. Support loading is regional and unbalanced along the inclined direction. The critical layer of overlying strata migrates, and bearing structures formed by breaking the critical layer exhibit cross-layer generalization along the inclination. The upper region has a cantilever beam structure in the basic roof rock layer; the lower region has an inclined masonry structure with multistage ladders in the breakage basic roof rock layer. Application of a false-inclined working face layout with the tailgate ahead of the headgate and an arc arrangement (radius 28.65 m, arc length 10–20 m) in variable angle areas, and regional control of support working resistance and top-coal caving amounts, control regional failure overburden. Safe and efficient mining was achieved, with the monthly production and recovery rates reaching 344,900 t and 85.86%, respectively. Our results expand the scope of fully mechanized top caving mining and have important theoretical and technological significance. Keywords Steeply inclined seam . Variable angle . Fully mechanized top caving mining . Bearing structure generalization . Support stability . Regional control
1 Introduction Top-coal caving mining was first applied to the mining of steep coal seams in France, Spain, and the Socialist Federal Republic of Yugoslavia in the early twentieth century; the technique was later extended to thick coal seams in the mines
* Wang Hongwei [email protected] 1
School of Energy and Mining Engineering, Xi’an University of Science and Technology, Xi’an 710054, China
2
Key Laboratory of Western Mine Exploitation and Hazard Prevention, Ministry of Education, Xi’an 710054, China
3
State Key Laboratory of Coal Resources in Western China, Xi’an 710054, China
4
Yanbei Coal Mine, Huating Coal Industry Group, Huating 744100, China
of the Soviet Union, France, and other countries during the early 1950s [1]. Fully mechanized caving mining technology was introduced in China in 1982 [2]. Over the past 20 years, there has been significant developme
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