Process of hard coal caving face
Surface is intermediate stiffness immediate roof conditions, can be divided into the following three conditions: 1) coal thickness of 2m, the immediate roof to 2m thick mudstone; 2) coal thickness of 3.6m,
mbt cipő, the immediate roof of 1.6m of top coal and 2m thick mudstone; 3) coal thickness of 5m, the immediate roof top for the 3m and 2m thick mudstone coal. The three cases illustrate, Wangcun mine face three soft-light the top part of the intermediate type of direct stiffness. Mine conditions under Wangcun: mining height 2m, 2h a 2m, 3.6m, 5m, E a 500X10. kPa, L a 4m,), a 2.4 × 10N / m. ,: 10. , A-20. Conditions, can be calculated the P ~ △ z relationship shown in Figure 1. Visible, Wangcun ore mining face three soft coal refer directly to the top of the stiffness of the light 1 caving Wangcun mine rock face frame rigidity and the curve seems like in between zero stiffness, its frame work and roof sink resistance volume was approximately hyperbolic relationship. Face stand a reasonable working range for the Al-0.4 ~ 0.8m, supporting frame work of a reasonable strength of 100 ~ 300kPa, a single frame supporting area 6m calculated in accordance with, the frame work of the normal resistance range for the 600 ~ 1800kN / frame. Consideration to increasing pressure when the load factor of 1.3, the maximum rated operating resistance 2340kN / frame. Wangcun mine caving light bracket selection of 2400kN / frame is reasonable. 4 Conclusion (1) The three soft seam gently rock side bracket system, the control has a key role in supporting the immediate roof rock is still rock. (2) Wangcun mine-light surface is intermediate stiffness immediate roof, the roof frame work of resistance and the amount of subsidence was approximately hyperbolic relationship. (3) Wangcun mine gently reasonable working surface resistance range 600 ~ 2340kN / frame, frame selection rated resistance 2400kN / frame is reasonable. (4) For the three-soft coal, the future need to strengthen the role of the stiffness of the floor. References: [1] Huang enjoy. Chenghe Mining Wangcun mine caving feasibility study report [R]. Xi'an: Xi'an University of Technology, 2003. C23 Liuchangyou, Ming-Gao Qian, Cao W, et al. Stope directly to the top of the structure and mechanical properties of cut degree CJ3. China University of Mining. l997, 26 (2) :20-23. [33 Liuchangyou,
radii shoes sale, QIAN Ming-gao. Cao Sheng, et al. Stope directly to the top of the bracket and the relationship of rock mechanism [J]. Coal Science, 1997,22 (5): 47l an 476. [43 Cao Shenggen, Liuchangyou, QIAN Ming-gao. Stope stent system with the stiffness of rock [J]. Mine the pressure and roof management. 1997, (3-4): l6 a l9. [53 Liuchangyou, Shenggen Cao, Fang Xinqiu. Relations and their rock stope monitor and control stents [M3. Xuzhou: China Mining University Press, 2003. (Continued from page 14) to adopt an important factor, choose the best design under the conditions of hard coal face orientation is to promote caving is an important measure. (8) caving mining with hierarchical compared with the tunneling rate, low cost,
tory burch outlet, the block rate, the unique advantages of higher production efficiency, promote the use of caving mining method will help improve the economic efficiency of enterprises. (9) coal mining best caving 3 parameters: machine cutting height 3. O ~ 3.5m, caving step 0.6m; control zenith distance 6m; taken place more than 1:1; stand working resistance 5500kN / frame; effort role position ≥ 4.0m. In the above parameters,
herve leger sale, the control and machine cutting height from the top is the main influence parameters,
Oakley sunglasses sale, followed by caving step, stand the least impact resistance work. (10) 3 coal seam in the crack with two or more conditions for devolution of the top two coal mining is appropriate, especially in the larger region thickness, its cost is very significant. However, we must first focus on the direction of crack and face a reasonable match, not developed cracks and face almost parallel to the second (diagonal 10 ~ 2O.), The main development direction and face almost vertical cracks (diagonal 10 .) match is the best, if the primary fissure, and parallel with the face, then easily lead frame before the roof fall. Development of a single group without fracture coal seams in place will be very difficult, generally require blasting top-coal weakening. 5 problems and recommendations (1) row of the first frame too, the difficulties hindering the passage of surface mining production of important factors. (2) maintain the mechanical end of the first to achieve the transition frame, the first row of the next frame is normal caving equipment, improved main content. (3) continued to expand in the cracks do not develop the thick coal Ida East instability or erosion area caving industrial test. (4) to further strengthen the caving surface of coal dust injection and integrated management of surface mining is the next important element. Mine roof pressure and Management 2005. № l · l7 ·
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