Study On Range Of Ore Under Open Pit In Dahongshan Iron Mine

Due to the rapid development of social economy,the demand of all kind of mineral resources increases as well.Many mines turn into deep mining because of the depletion of open and shallow resources.Large-scale open mining has formed a large stress disturbance on the rock mass around the stope,while underground mining on the basis of the disturbance will form a more complex secondary stress field and cause further deformation and failure of surrounding rocks.For some surface and underground combined mines,the closer distance mining face arranged to the slope,the more mineral resources recycled,while causing the greater the security hidden danger to the slope.Searching the law of slope failure caused by underground mining and looking for reasonable pressure ore angle to draw the pressure ore boundaries of slope are conducive to mine reasonable coordinate mining and to ensure the safety of mines.Due to open pit pressure limit in Dahongshan iron ore,contradictions between open-pit with underground mining increasingly prominent.In this paper,through combining similar material simulation and numerical simulation,studying on the open pit reasonable pressure ore boundaries and redrawing the pressure ore range will liberate the security pillar for open pit,while the transition of open pit and underground mining will realize.In order to achieve the goal,the following research work will be done:First,do the similar material simulation experiment.According to the actual situation of mine site to build physical and mechanical similar model in the lab,excavate the ore and observe the result of the experiment and record the relevant data to carry out comprehensive analysis.Second,build mine numerical analysis model of related parameters and boundary constraints by FLAC^3Dand excavate the model to simulate gap roof movement and slope deformation.At the same time,decorate spots in the mining model to record the change of the displacement and stress situation,through the observation data to analyze the results of numerical simulation.Third,ensure the reasonable pressure ore angle and redraw the pressure ore boundaries to liberate the security pillar for open pit and realize the transition of open pit and underground mining through the results of numerical simulation and similar material simulation experiment,and connecting with the field measured data analysis.This topic research will provide technical support to mine safety and efficient underground resources recycling,and eventually achieve the goal of the sustainable development of mines.