A STUDY ON THE WORKING SLOPE ANGLE IN OPEN PIT

Based on the production tests carried out in Nan Fen Open-pit Iron Mine, this paper discusses the law of the change of grouped benches working slope angle in the mining production. On the basis of mining operation model and layered strip ore deposit model, the simulation of mining operations was performed and annual stripping tonnages were balanced and optimized. The results of the simulation showed that there is an undulant decrease in mining cost with the increase of working slope angle due to different grouped benches structures. In accordance with the equivalent principle, the working slope angles possess equal value changing regions which overlap each other. The reliable and optimized values of the working slope angle are in the optimum equivalent region in which every scheme of grouped benches structures is considered to be optimum.