Stability Analysis Of Slope In Open-pit To Underground Mining Of Shibao Iron Mine

With the large-scale mining in recent years,the shallow resources are gradually exhausted,and the mining is developing to the deep.For opencast mining,the stripping ratio increases gradually,and the other high and steep slopes need to be maintained to varying degrees.Therefore,in order to realize the sustainable mining and utilization of deep orebodies,it is the main form of the future development of mining industry to change from open pit mining to underground mining.However,the disturbance of underground mining may lead to the instability of open pit slope,and then affect the underground development and mining work.Therefore,ensuring the stability of the upper pit slope in the process of underground mining can not only ensure the sustainable and efficient production of the mine,but also can be used for the long-term development of the mine.Provide economic support.In this study,Shibao Open Pit Mine is taken as the research object,combined with the engineering geological conditions and the occurrence characteristics of the orebody,the mining methods that can be used in the open pit to the underground are analyzed.On this basis,the FLAC^3Dnumerical simulation software is used.The stability of open pit slope in different parts of underground orebody mining in Shibao Iron Mine is calculated and analyzed,with emphasis on the stress and displacement analysis of slope stability at 2#and 3#sections after Shibao Iron Mine is transferred to underground mining.The results of this open-air to underground study are as follows:?1?Through field investigation and field sampling investigation,the detailed geological data and data of Shibao Iron Mine are collected,and the ore and rock samples in typical areas of slope are sampled,and the physical and mechanical parameters of ore and rock specimens are determined.It provides the modeling basis and accurate rock mass physical and mechanical parameters for the later numerical simulation.?2?Based on the topographic contours,geological profiles,strata,lithology and other geological data of the mining area,combined with the specific underground mining method,the 3D geological model of 3DMine mine and rock in the mining area is established,and the interface program between 3DMine and FLAC³DD software is used.The 3D geological model of ore and rock is imported into FLAC³DD numerical simulation software,which not only simplifies the modeling process of numerical simulation,but also maintains high accuracy while the model is closer to the real situation of mining area.?3?The parameter calculation of the established numerical model is carried out,and the cloud images of displacement,stress and shear strain rate after forward mining and backward mining are analyzed respectively.The results show that the two mining sequences will have different degrees of influence on the slope stability of the two mines,and the first mining room will have a greater influence on the near slope stability,but the slope will not be unstable.Among them,backward mining has the least effect on the stability of the two pit slopes,so this part of the orebody plans to adopt backward mining.?4?The ore bodies below the final boundary of the Middle East pit can be exploited by sublevel caving method without bottom pillar,which can be used to cut the slope of the south and east sides of the Middle East stope with landslide trend,which can not only solve the source of the overburden.Moreover,it greatly slows down the slope angle of the mine,which is more beneficial to the stability of the slope.By analyzing the displacement and stress cloud images of the typical 2#and 3#sections before and after the formation of overburden and the different segments of underground mining,it can be seen that with the further mining of different segments of the underground ore body,the displacement and stress cloud diagram of the slope before and after the formation of overburden and the different segments of underground mining are analyzed.The displacement at the foot of the south and north slope of the Middle East pit has changed obviously,among which the displacement of the south side of the 3#section has been obviously changed.The change is relatively large.It is necessary to strengthen the monitoring of the site in the actual production process,and provide the theoretical guidance for the prevention and treatment of the slope after the mine is transferred into the underground.After the ore bodies of the different parts of the Shibao iron ore are underground mined,the stability of the slope of different parts is affected by the underground mining disturbance,and the displacement of the two pits is different,and the displacement of the south side of the Middle East pit is slightly larger,But all the displacement values are in the normal slip range.The monitoring and monitoring of the south side slope of the Middle East will be strengthened when the underground mining is actually carried out.