Abstract: In order to ensure the safety and stability of synergistic mining of underground orebody and openpit orebody,the probability integral method and SUFER software are obtained according to the occurrence condition of the orebodies,the surface subsidence results are predicted.The predicted results are compared with the FLAC3D numerical simulation results through the relevant provisions in the "Nonferrous Metal Mining Design Code",so as to analysis the influence of the mining methods on the stability of open pit located on the surface.The deformation prediction results by probability integral method show that after underground mining,the whole open slope is within the protection range of grade III structure;the computation results by using numerical simulation method show that the whole open slope is within the protection range of grade II structure after underground mining.The probabilistic integral method under ideal conditions is roughly consistent with the results of FLAC3D numerical simulation method,they are within the allowable range of safety regulations,which have guidance reference for the synergistic mining of underground and openpit,besides that the accuracy of the two methods are confirmed.

Key words: Synergistic mining,Probability integral method,FLAC3D,Surface collapse,Movement and deformation