Abstract: Based on the known rock stratum characteristic information,predicting the rock stratum lithology distribution characteristics of the position to be drilled,which is conducive to timely and dynamically adjust the drilling speed and the bit pressure of the perforation rig and improve the perforation speed in the process of openpit mining.On the basis of Legendre polynomial,combined with the probability sensity polynomial function approximation method and the least square method,the prediction model and calculation method of borehole lithology distribution characteristics in openpit mine are established and verified by the exploration boreholes information of a certain leadzinc mine.The results show that the established prediction model on borehole lithology distribution characteristics can predict the lithology distribution characteristics at any position between two boreholes according to the known borehole rock stratum distribution characteristic information.The maximum error of the prediction result is at 3.124%,and the accuracy can meet the needs of the prediction of rock distribution characteristics in the perforation operation of an openpit mine.The established prediction model has stronger adaptability to layer rock formations.

Key words: open pit mining,Legendre polynomial,lithology distribution characteristics,prediction model,drilling efficiency