Abstract: With the development of openpit mining into deep concave mining stage in China,the difficulty of land acquisition in the drainage field increases day by day,and the cost of land acquisition increases continuously,which promotes the development of the drainage field to a high and steep direction.Although the development of high and steep drainage field reduces the land acquisition and the production cost of the mine,the increase of the height of the drainage field also brings a series of problems.In this study,the stability of the increased and expanded capacity of the inner dump was analyzed with the surface mine in jiuxian county of Hequ county as the engineering background.Rhino3D was used to quickly build a 3D model based on the initial data of the contour line of the drainage field in the open pit mine of hequ county.Meanwhile,Slope and FLAC3D were used to analyze the stability of the slope when different heights were increased.

Key words: open pit mine,dump,Rhino3D software,increased capacity,slope