Abstract:

By investigating on the joints and fissure in Sizhuang mining area of Jiaojia gold deposit,the altitude and average spacing of joint fissure of the hanging and footing wall were obtained,and the data were statistically analyzed.Using CSIR rock quality evaluation method,the rock quality index RQD was calculated by the joints density.The rock integrity coefficient was used to represent the strength of rock masses by calculating the RMR whose magnitude could indicate the stability degree of rock masses,and predicted the stope span and their stability time.The results show that more fissures develop in surrounding rock on the plate than in the orebody and footwall surrounding rock, and the rock mass strength is more influenced by the distribution of joints when the joints have angle of 30° to 75°;orebody and footwall of surrounding rock are stable,while surrounding rock on the plate has poor stability.Because of the poor stability of the surrounding rock in No.7-2 orebody,Sizhuang mine area,timely effective support is needed to limit the surrounding rock deformation and failure after exposing;Due to decreasing of surrounding rock with the decreasion of the ground elevation, stope needs timely support to ensure the safety of operations when exposed to deeper ore body.This study can be used as an important reference for optimizing of mining stope structural parameters and analyzing of its stability,and is essential value to safe production.

Key words: Joint fissure, Dominant structural surface, Rock body stability, Evaluation, Sizhuang mine area, Jiaojia gold mine