| Hemushan iron bed belongs to the one of high temperatured pneumatolito-hydrothermal meta-somatism, which exists in the strata contact between diorite and Zhouchongcun Fm and adjacent limestone.The angle and horizontal thickness is respectively from45°to50°and from10m to75m. The surrounding rocks of hanging wall are relatively stable, while the ore body and the surrounding rocks of footwall are all unstable. In order to less engineering quantities of excavating and realization of effective mining,a new mining method is presented to combine induced caving technology with no pillar sublevel caving method in Hemushan mine,which is a efficient mining scheme with double working faces running parallel. However, due to insufficient angle of iron ore body and bad fluidity of ore rocks, there are many residual ore left in footwall. In order to reduce ore loss, it is a must to reasonably recover residual ore of footwall.On the basis of extensive investigation and analysis of mine currently mining condition, an evaluation is made for the shape and quantity of footwall residual ore. In order to recovery the footwall residual ore, a proposal is presented to reasonably excavate a certain height rock at footwall. The development of recovery projects depending on the recovery conditions of upper levels. In the laboratory, after simulating the recovery situation under different digging rock height, we get the relationships between mining indexes and excavating heights. With the current of various economic indicators, the best digging rock height in Hemushan residual ore recovery is7m. To ensure safety, in the light of classification in stability of differert rock mass and under the application of engineering analogy method, we adopt different support parameters for different rock mass, guaranteeing the operation of recovery. |
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