Stability Analysis And Parameter Optimization Of Stope In Gentle Inclined Thin Ore Body In Western Hubei

Demand status of iron ore in our country is briefly stated in this paper, and development tendency of domestic mining is analyzed, meanwhile, mining methods used to mine gentle dip thin ore which can't be easily mined are summarized, among which the proportion of room-and-pillar mining method is highest. In view of this, taking the mining method for example, related mechanics theory is used to analyze the stability of roof and pillar after the simplification of stope, and the distribution rule of each physical quantity(stress, displacement) is obtained. Then two forms of stope structure of horizontal ore are established with FLAC3D, a finite difference software in the paper:(1) Considering that carry-scraper can make a round work in adjacent stope, the pillar gap is fixed as 4m,(2) Room span is equal to pillar gap.Then numerical simulation of the two forms is conducted respectively, making a comparison of the maximum tension stress in roof in the condition of the same recovery, and the smaller one is chosen for following analysis. The second form are selected for further numerical simulation. Then the influence of physical and mechanical properties of ore and rock, geo-stress, stope structure parameter to the stability of stope is analyzed respectively, and the results are shown as following:(1)Two kinds of ore, the mechanical properties of which are greatly different, are chosen for numerical simulation in the paper, the results of which shows that the physical quantities slightly vary, but the mechanical properties of ore itself influence the safety of mining.(2)For the influence of geo-stress to stope safety, it can be drawn from numerical simulation that high horizontal stress around the stope is favorable to sustain the stability in the center of roof, the increase of vertical stress (depth) leads to the increase of maximum tension stress in roof and the linear increase of pillar average vertical stress, which accelerates the break of roof and pillar.(3)The influence of stope structure parameters mainly can be concluded as:there is little influence of the room height to stope roof, at the same time, along with the increase of depth, there is a little increase in average stress of pillar. But to the influence of pillar stability, it mainly reflected in the variations of pillar supporting capacity, because the increase of pillar height decreased pillar supporting capacity (size effect). The maximum tension stress increases with the room span and the increasing range become larger. When the room span is small, there is little influence of width of pillar to the maximum tension stress, but when the span is big enough, increasing the width can decrease the maximum tension stress of roof.Finally, aiming at gentle inclined thin ore body in Western Hubei, using numerical simulation, optimum structure parameters and ore recovery are obtained, then the functional relationship between recovery and depth is gained.