Abstract: The ore body of the Zuoan Gold Mine of Otenko Co.,Ltd.is of high grade,but the ore rock is relatively broken,and the structure faults crisscross the mine area.The rock stability is not good,which leads to the difficulty of mining the ore body.At present,the gold mine adopts the upsidedown approach for mining in relatively fractured areas,in order to improve mining efficiency,it is a trend to study and explore the safety of large section approach.Midas/GTS is used to establish the 3D digital geometric model and grid division of the research object,and then it is imported into FLAC3D software to complete the calculation and analysis of three different sizes of roadway excavation.The safe and feasible approach section size was finally determined to be 4 m×4 m.

Key words: Upward route method, Large section, Numerical simulation, Security