Study On The Crushing Characteristics And Fine Particle Migration Law Of The Filling Body Above The Caving Stope

Chengchao Iron Mine adopts the caving method to recover the security pillar under the filling pit.The cover layer is mainly composed of the initial cover layer formed by top caving and the fragments of the filling body falling above it.Whether the phenomenon of particle flow is serious and whether the parameters of the stope structure are reasonable under this special working condition need to be solved urgently.Therefore,in this paper,through the literature survey,filling body crushing test,numerical simulation and other methods,the block size distribution characteristics of the filling body above the caving stope after crushing and the characteristics of fine particle migration during the caving method mining process;The initial overburden block size was determined;and the stope structure parameters under the influence of the filling body above the caving stope were optimized.Firstly,through the qualitative analysis of the ore recovery factors under the influence of the filling body above the caving stope,combined with the specific working conditions of Chengchao Iron Mine,it was determined that the fine particles "flow through" in the caving process will cause premature leaning of the ore The composition of the overlying rock mass and its crushing characteristics and the structural parameters of the caving stope are the main controlling factors affecting the recovery of the ore under the mine filling stope.Secondly,through the indoor filling body crushing characteristic test,the filling body sample is crushed and sieved to obtain the block size distribution of the filling body sample after crushing.The calculation shows that the fractal dimensions of various filling body fragments are mainly concentrated in 2.1 ? 2.4 The block size distribution has a good self-similarity between the block size and mass fractal characteristics after the filling body is broken,and the block size distribution of the mine cemented filling body after the collapse is predicted,and the mine filling body is broken.The block size distribution is: <0.1m for 24.07%;0.1m ? 0.3m for 23.31%;0.3m ? 0.5m for 17.63%;0.5m ? 0.7m for 15.10%;> 0.7m for 19.89%,which can be used as a fall Reasonable predicted value of block size distribution of backfill above the stope.Finally,the numerical simulation software was used to simulate the "through-flow" of fine particles in the process of ore drawing and multi-stage ore drawing.The simulation results show that the larger the cover layer is,the more obvious the fine particle seepage will be.Slow down the occurrence of fine particles flowing through the ore.It shows that the mining pit structure parameters are set at the segment height of 17.5m,the approach spacing is 15 m,and the ore withdrawal step is 4m.