Research On The Determination Of The Strong Mining Boundary Of The Deep Residual Mine In The High Slope

With the increase in the depth of open pit mining,many mines are facing difficulties in recovering deep ore bodies.How to determine the better mining method of ore body has become an important issue in open pit mining research.In the recovery of residual ore,it is necessary to study the realm elements to ensure the recovery of mineral resources as much as possible in terms of safety and economy.Therefore,the study of the elements of the open-air boundary is of great significance for ensuring the long-term development of open-pit mines.Based on the engineering background of Jinpo Kunming Steel’s Dapo Iron Mine,this paper proposes to convert the original hillside type into a concave mining method to recover the deep residual ore body,and determine the preliminary boundary plan from the perspective of stability,and economically rational stripping.Compared with the actual displacement monitoring and three-dimensional simulation numerical simulation,the program verification is carried out to provide a better residual mine recovery plan for Dapo Iron Mine.The main work of this paper includes the following aspects:（1）Based on the analysis of the current research situation and the existing geological survey data of the Dapo Iron Mine,the resource recovery method of the Dapo Iron Mine is determined based on the actual situation that the northeast of the Dapo Iron Mine cannot be expanded.（2）After analyzing the geological survey data and drilling data of Dapo Iron Mine,the site survey was carried out.After the sampling plan was determined,the core was taken for the basic indoor physical and mechanical tests,and the physical and mechanical parameters of different geotechnical bodies of the Dapo Iron Mine were obtained.（3）According to the current situation of the Dapo iron ore and the occurrence of the ore body,a three-dimensional surface model is established to optimize the parameters of the open boundary.When the bottom perimeter width is used as the fixed value,different values of slope angle and depth are set to carry out orthogonal test design and establish response surface.The stability coefficient under the orthogonal scheme is used as the basis for evaluation.Meet safety requirements.（4）Statistically summarize the changes in iron ore prices in recent decades,establish a time series model,and average the iron ore prices under the designable mining years of the Dapo Iron Mine.Without changing the mining conditions of the Dapo iron ore,the original cost parameters were used to obtain a reasonable economic stripping ratio of13.02t/t for the Dapo iron ore,which is greater than the boundary stripping ratio of11.70t/t under the previous final scheme.（5）Using Flac^3D to establish the final boundary model under the current stope and mining plan,the stress and displacement under the final scheme are increased compared with the current situation,but the plastic zone does not penetrate;then the actual displacement is compared with the simulated displacement.The research method,there is no large difference in quantity between the two,indicating that the high-steep slope under the optimization scheme meets the stability requirements.