Parameter Design And Stability Analysis Of The Boundary Roof Pillar In The Open-pit To Underground Of An Gou Molybdenum Mine

The transition from open pit to underground mining is too thin for the top pillar to cause collapse,which poses a great threat to underground production personnel and equipment.If left too thick,it will easily cause waste and reduce ore recovery.The design of boundary pillar parameters is a complex problem.We should consider the thickness of the top column and the sequence of mining.There is no uniform method for determining the relevant parameters of the boundary pillar at present.Taking the transformation from open pit to underground mining in An Gou molybdenum mine as an engineering background,the numerical simulation and genetic algorithm are used to establish the numerical simulation of evolution.The optimal parameters of the top pillar of the outbound area are obtained,and the limit equilibrium method is applied to analyze the stability of the boundary pillar.The main contents and results of this paper are as follows:(1)Introduced a system of An Gou deposit engineering geological conditions,hydrogeological conditions and An Gou Mo No.1 orebody spatial distribution characteristics,orebody characteristics and ore connection basis,finally introduced the mine No.1 opencast mining scheme of underground orebody,which laid a foundation for the subsequent.(2)Through the investigation results of mine geological data and field geological conditions,the quality grade of RMR classification and GSI classification is the quality classification of rock mass on the rock mass based on the mining area mining area,according to the Hoek-Brown criterion,the rock mechanics reduction that suitable for rock mechanics parameters of the mining area.(3)In this paper the An Gou deposit open-pit to underground work as an example,according to the analysis of the optimization of the boundary pillar reservation problem,using simulated complementary ways of genetic algorithm and the numerical analysis of evolution,and three-dimensional numerical iterative mode on the boundary pillar reservation scheme,to exit the optimization scheme of top circle column,column top steps provide reserve parameters and optimize the way for state.(4)The mechanical model of the boundary top pillar is established,and the possible failure modes are analyzed.The stability of the safety pillar of No.1 ore body in An Gou molybdenum mine is analyzed by the engineering analogy method and the limit equilibrium method.