Study On Optimizing Of Structure Parameter Of Non-pillar Sublevel Caving In Daye Iron Mine

It is carried out to optimise stope structure parameters of non-pillar sublevel caving according to the cut-off grade for ore drawing in the thesis. It lays emphasis on the study of the problem from three aspects including theory, experiment and numerical simulation.The relationship among extreme cut-off grade for ore drawing, combination cut-off grade for ore drawing and undilution cut-off grade for ore drawing and the one among extreme cut-off grade for ore drawing, combination cut-off grade for ore drawing, undilution cut-off grade for ore drawing and the stope structure parameters are analized based on theories. Although different cut-off grades of ore drawing and corresponding ore drawing are based on different theoretical basis, them rely on ellipsoid theory of ore drawing and are affected by the theory with its advantage and localization. And there are still internal essential relations among them, that is, extreme cut-off grade ore drawing and undilution cut-off grade ore drawing are one special kind of combination cut-off grade ore drawing, but have respective characteristics, applying conditions and will lead to different economic effect.As for numerical simulation, Graphics display and change law of force between particles is firstly studied by the software of PFC during the course of ore drawing, and the process of ore drawing for non-pillar sublevel caving is reshown. The change law among drift interval, sublevel height and drawing pace is studied according to existence of ore body and physico-mechanical properties of rock in underground workshop. There are eight combination schemes for the stope structure parameters and the best scheme is determined by PFC.At the aspect of physical simulation, the ore drawing experiments of combination schemes with different drift intervals, sublevel heights and drawing paces are carried on to verify the result from numerical simulation. The best stope structure parameters are the sublevel height of 8m, the drift intervalof 15m and the drawing pace 3.2m.According to the best stope structure parameters from numerical simulation and physical simulation, the blasting design of stope structure parameters is optimised, considering fact of the underground workshop.