Study On Bottom Structural Stability And Control Technology Of Large Parameter Stope In Deep Metal Mine

With the depletion of shallow resources on Earth,metal resource extraction is gradually shifting towards the deeper part of the Earth."Marching towards the deeper part of the Earth is a strategic scientific and technological issue that we must solve.China’s deep mineral resources,especially iron ore resources,adopt a high production capacity and efficient development model,and the layout of large structural parameter mining sites has become an inevitable choice for achieving large-scale and efficient mining of deep mineral resources.The bottom structure belongs to the "throat" of the mining area,ensuring its stability during the mining process is extremely important and significant for the safety production of the mine.The Sishanling Iron Mine,as the largest deep well hard rock mining mine in China in the future,uses a large diameter deep hole stage open pit followed by filling mining method.The bottom structure of the mining site has the following significant characteristics: large structural parameters,and the cross-sectional area of the bottom structure mining roadway is as high as 17.56m2;In deep well mining,the stress environment of the bottom structure is complex and there are many disturbance factors.It is not only affected by the high ground stress of the deep well,but also involves excavation disturbance,frequent large-scale blasting disturbance,and ore drawing disturbance;In addition,the Sishanling Iron Mine adopts a large-scale panel mining layout,and the bottom structure roadway has a longer service life.In summary,it is of great significance and value to conduct research on the stability of the bottom structure of large parameter stopes for Sishanling Iron Mine.This article comprehensively studies the stability of the bottom structure of the large parameter mining site in Sishanling Iron Mine through various methods such as on-site research,theoretical calculations,numerical simulation experiments,and engineering analogies,and proposes stability control measures.The main research content and achievements are as follows:(1)Conduct a survey on the bottom structure of Sishanling Iron Mine,summarize the characteristics of the bottom structure of the large parameter mining area in Sishanling,summarize the existing and potential failure forms of the bottom structure roadway,and summarize the factors affecting the stability of the bottom structure roadway.(2)Using Flac3 D software to analyze the stability of the bottom structure of the entire mining process under the action of high ground stress in deep wells,the results show that when the bottom structure is formed,there is a significant stress concentration phenomenon in the bottom structure pillars,especially at the intersection of tunnels.However,when the ore collapses,there is a more significant tensile stress concentration phenomenon in the bottom structure pillars,especially at the intersection of tunnels and triangular pillars.(3)Using Flac3 D software to study the stability of the bottom structure under the action of large blasting dynamic load,the results show that under the action of dynamic load,the stress concentration area of the bottom structure is roughly the same as that under the action of static stress,but its stress concentration is more obvious than that under the action of static stress;Compared with static stress,the deformation of the bottom structure under dynamic load shows a more significant time effect.(4)The PFC discrete element software was used to analyze the impact of mining and mining processes on the stability of the bottom structure.The results showed that when mining,there would be a significant impact on the surface of the bottom structure pillars.Reserving an ore cushion can greatly reduce the impact damage of mining,and the initial stage of mining can also cause significant disturbance to the bottom structure.Therefore,timely mining should be carried out to reduce the impact of mining on the bottom structure.(5)According to the results of the stability analysis of the bottom structure,combined with the theoretical analysis and calculation,the research on the prevention measures of instability is carried out.The results are as follows: the layout of the bottom Structural engineering is redesigned;Optimized blasting and ore drawing processes;Designed support;Propose a monitoring plan for the ground stress and anchor stress of the bottom structure.