Engineering Conditions And Analysis On Stability Of Ore-Rock In Deep Part

Copper-nickle mining area of Jinchuan is one of the three bases for integrated utilization of resources and the largest production base for nonferrous metal-nickle, platinum, and so on. The ore body of Jinchuan mining area immerses in high stressed stratum which surrounding rock masses are very poor, plus that complex geological tectonism; making exploration condition is rather severe. With the increasing in depth of mining, now mining depth has already reached one thousand meters distant from surface. How to maintain stability of backfill becomes the earnest concern of engineers in Jinchuan No.2 district mining area. The author conducted research on technologies of controling stability of backfill which used different recovery modes, based on key project of technological breakthough of Jinchuan, by using site survey and numerical analysis. The main results are as follows:(1) Site survey for rock mass of ore body marked No.1098 in Jinchuan No.1 area have been conducted and found that:â‘ strength of intact rock is high;â‘¡rock mass discontinuities are rather developed;â‘¢in-situ stress is large and horizontal stress is larger than vertical stress;â‘£rock discontinuities are influenced by soften effect of water.(2) Normal experiments of rock mechanics can provide some guidance for choosing parameters of rock engineering project. It is correct to combine experiment results with site investigation so as to derive the proper parameters for rock engineering. Data gotten in normal experiments should be received objective discription and are served the greatest extent for rock project.(3) Based on the previous tunnelling arrangement of 'rocovery one spacing two', the author proposes optimizational program of 'rocovery one spacing three'. Numerical analysis using FLAC3D software has been conducted to set up model to analyze stability of backfill of the two mentioned methods. Results show that the advantages of'rocovery one spacing three'are threefold: firstly, the difference between the major principal stress and minor principal stree is relatively small and the stress state tends to be uniform; secondly, vertical displacement of rock mass is small and the degree of uplift in area of recovery is relatively low; and thirdly, deformation of surrounding rock has been effectively controlled and disturbance is effectively reduced leading to release of high stress and maintaining stability of backfill.