On Mechanics Stability Of Stope And Preliminary Mining Projects In No.2 Mining Of Jin-chuan

Jin-chuan nickel mine with enormous mineral deposit is strategic important for the national economy. In recent years, with the double-level mining at depth, horizontal jamb and vertical jamb had been formed. The underground pressure emergence is very obvious, drifts were strongly deformed, especially the more remarkable deformation on the 1178m drift. So it is necessary and urgent to study the mechanics problems of underground projects in the No.2 Mining Area of Jin-chuan and evaluate the stability of them.This paper relies on the technological project of the Jin-chuan Company "Effects of 1150m Macro-Horizontal Jamb Mining on the Redistribution of Stress Field and the Evaluation of Drift Stability in the No.2 Mining Area of Jin-chuan Nickel Mine". Based on the investigation of stress field data, geologic conformation, the distribution of mainly fault, the characteristic of rock mechanics, the mining process and the locations of projects, etc., using the theory of elastic-plastic mechanics and rock mechanics, by means of finite element numerical simulation, we study the stress state in wall rock, horizontal jamb and vertical jamb, the interaction between them, and evaluate the stability of drifts in hanging wall rock. The main conclusions described following already had been adopted:1. The tri-dimensional finite element model of the No.2 mining area were built for the first time, so we can stimulate the mining process year by year.2. By means of the finite element program ANSYS and combining the procedure codes compiled by ourselves, the complex 3D initial stress field were precisely stimulated and the 3D stress gradient in gravity direction were preserved.3. Evaluating the stability of the horizontal jamb and vertical jamb on the base of tri-dimensional numerical simulation combining the principle of elastic-plastic mechanics, drawing the conclusions that the two jambs have been in plastic statement in 2004, and they can be mined in appropriate time.4. Stimulating the other three planned schemes. The results indicate that it is invalid to distinctly change the stress state in the horizontal jamb, vertical jamb and underground project through adjusting the mining process. So it is not necessary to adapted the mining scheme.5. Studying the effects of fault, filed stress and drift directions on the drift stability.6. Finding the critical distance between stope and drift, and advising that the coupled action of stress concentration should be considered in designing drifts.