Study On Mining Optimization For Hidden Danger Resources And Control Technology Of Mining Damages

When stoping ore body of-220m middle to-570m middle in Sanxin Gold and Copper Co.,Ltd.,there are 10m crown and sill pillars between middles.The ore grade is relatively high and recoverable reserves are considerable.The company decided to recycle the residual pillars to improve the utilization rate of mineral resources,extend the service life of the mine and ensure the sustainable development of the mine.Compared with the mining of the middle ore body,the safety of the crown and sill pillars is lower.On the one hand,the backfill around the crown and sill pillars is unstable.On the other hand,blasting vibration will also affect the stability of the backfill in the mining process.In addition,the surface subsidence increases,it needs to be strictly controlled within the prescribed range.Based on the project of"Research on recovering technology of residual ore under backfill",the paper used field test,physical test and numerical simulation to analyze the recovery safety of residual pillars under the backfill,carry out study on mining optimization for hidden danger resources and control technology of mining damages to achieve safe production.The following main research works and results are obtained:(1)Engineering geological survey and Field test:By collecting geological data and physical mechanics data of backfill,the distribution of residual ore body is conformed,and the backfill quality on the upper and lower part of crown and sill pillars is clear.Moreover,the typical faults,joints and fissures in the typical site were investigated,and calculate the density of structural planes;Collecting the rock physical mechanics test data and supplementing tests for the ore of the mining area;Carrying out blasting vibration tests in the points of filling pillars and obtaining filed data.These results provide the basis for the following numerical simulation study.(2)Studying on the optimization of the top and bottom columns of the middle section by the numerical simulation.The development laws of stress field and stope deformation are obtained after the calculation.Then optimization scheme is designed and feasibility is verified:The room size of the first slice is 4m×4m,and the room size of the top slice is 4m×5m.It remains 1m ore body at the roof and adopts the sequence of“stoping one room at a distance of two rooms”.(3)Combining with field vibration test,the influence of blasting vibration on the stability of the column is studied by numerical simulation.The relationship between the vibration velocity and burst center distance of the column under different maximum single dose is obtained,then combining with the safe velocity of the filling body,the relationship between the safety distance and the maximum single dose is y_s(28)3.96Q-3.17,so as to judge the influence of different maximum single dose on the interstitial column.(4)Studying the surface subsidence rule of the ore body after the middle part by the numerical simulation.The analysis and calculation results are as follows:the shape of the ore body,the formation of the ore body caused by the top of the surface subsidence is small,the vertical direction of the settlement on both sides is large;after the end of mining of the-570m in the middle of the ore body,the maximum settlement of the mine area of about 5cm.The maximum sedimentation value in the simulation range is about 8 cm outside the mine area,and the impact on the surface building is small.