The Filling Level Pillar Stoping In Optimization And Ground Pressure Control Research

With the development of mining exploration, many old mines are faced with problems of resource depletion, the recovery of residual ore body become the key problem of mining and the full use of the limited mineral resource of great significance. However, the recovery of horizontal pillar under the loose filling body, which is different the ordinary ore body mining, is more complex. Therefore, the recovery of the horizontal pillar safely and effectively is urgent technical problem to be solved in the similar mines. The paper is taking Tongling Lantau Peak non-ferrous copper-240m level pillar stoping as engineering background, the numerical simulation, theoretical analysis and in-situ pressure monitoring are used to study the mining optimization and the ground pressure control of the horizontal pillar under the filling body, the main contents and conclusions are as follows:(1) By plane strain models analysis using the large-scale finite difference numerical simulation software FLAC-3D, three different stoping sequence was researched. The results show that from the north to the south of stoping sequence is the best.(2) To study the recovery order of a single stope approach by using RFPA-2D finite element analysis system, results show that the drift stoping sequence of the end-center with "interval mining" gets the effective result, which is to the control the mining site pressure effectively.(3) Through analysis of loose backfill pressure distribution characteristics, the result is obtained granular pressure with uniform distribution in the vertical direction, its size is not equal to the gravity of the upper backfill; then making use of YEUNG Sum granular pressure theory to establish the mechanical equilibrium expression to theoretically solve the problem, get the distribution formula of the loose backfill pressure along the depth direction.(4) According to the occurrence status and stress characteristics of horizontal pillar, simplify the reserved roof as a rectangular plate, and then derive the safety thickness formula of the reserved horizontal pillar based on the rectangular theory and the limit equilibrium method.(5) According to actual actual production of the Phoenix Mountains Copper Phoenix copper, use the rode type tailings backfill method to exploit-240m level ore pillar, a total of three-layered with each of the hierarchical design height of3m, and for each hierarchical approach using the interval mining in the "mining interval every one taking one" way with the route cross-section specifications3mx3m and the reserved roof thickness4m.(6) According to the analysis of characteristics of multiple pressure monitoring, combined with the actual situation of the Phoenix Mountains copper level Pillar, the paper introduces three ways, such as a stress monitoring, displacement monitoring, acoustic emission monitoring to conduct joint monitor, and put forward the field ground pressure monitoring scheme, the analysis of field monitoring results shows that the stress, and the displacement of the roof not large, after the end of drift stoping, which can ensure the safety of the horizontal pillar recovery.