| According to the research results of non-pillar sublevel caving in the upper part of the second west mining area of longshou mine,after the mining of the last sublevel normal route,the residual ore in peach pillar and ridge is to be recovered by auxiliary route.First,a similar physical model was constructed based on the actual situation of the upper ore body in the second west mining area,and a combined mining method was used to carry out the mining experiment,so as to obtain the residual ore morphology of the stope after the end of the mining step.The mining results show that after the end of normal mining in the final section,the remaining ore has a higher recovery value.Secondly,according to the shape of the peach shaped pillar,the limit width and height of the auxiliary access road arranged at 1546 m level are not more than 3.8m according to the rectangular section.Combined with the actual roadway type and mining situation,considering the release of ground stress in the stope under the condition of caving method,three sizes of auxiliary access roads are designed.Third,to test the reliability of theoretical analysis results,the FLAC-3D numerical simulation software is used to simulate the excavation of the semicircular arch in the peach-shaped pillar stress and displacement distribution of roadway and surrounding rock after auxiliary route.Considering the particularity of 2.5m interleaving of the lower cementation filling and the last part of the normal route,four position schemes of 1.25 m under 1.25 m at 1546 m level and 2.5m under 1546 m level were selected to carry out excavation simulation for the auxiliary route.The numerical simulation results show that,due to the influence of the cementation backfill at the bottom,the auxiliary route at and below the 1546 m level is not suitable,and when the auxiliary approach is arranged at the 1546 m level 1.25 m,the size of the auxiliary approach is 4.3m×3.8m and 3.6m×3.0m,all meet the safety conditions.Fourth,through a comprehensive technical and economic comparison of the two auxiliary route sizes,it is concluded that the auxiliary route size of 4.3m × 3.8m is more suitable for the actual production of the mine.Residual ore recovery experiments were carried out on the optimal auxiliary route size.Combined with the results of the overall ore recovery test,it was concluded that the total recovery rate of the upper ore body reached 96.52%,and the mixed rate of waste rock was 12.52%.In the case of meeting the requirements of mine production,the ore recovery rate was increased by 9.1%.Based on the 4.3m × 3.8m auxiliary route,the main technology of auxiliary route mining is designed.In summary,the upper ore body in the second west mining area is mined by the Non-Pillar Sublevel Caving Method.The last sublevel of the residual ore is recovered using an auxiliary route,It can provide reference for similar mines... |
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