The Calculation Model Of The Stope Pillars’ Size In The Safety Pillar’s Exploitation With Filling Method In Chengchao Iron Mine

In order to fully recover ore resources,the filling method which reserves the stope pillar is being planed to use at Chengchao Iron Mine in the late for recovering the ore which is used as safety pillar at western district.The reserved stope pillar contains two types.One type is the top pillar of stope which is left by mining room with filling.The other type is the pillar of slope protection which closes to the caving area.This paper used theoretical analysis,numerical simulation and similar simulation etc.and combined with basic theories including theoretical mechanics,structural mechanics and elastic mechanics etc.to research the calculation model about reasonable size in the safety pillar’s exploitation with filling method in Chengchao Iron Mine.The research can provide guidance for ensuring the stope size in the practice of mine production and also provide reference for the similar projects.According to its force state with the filling method,the top pillar of stope can be simplified into four kind of mechanical simplified models.And this paper established the top pillar of stopes’ finite element numerical calculation model to simulate the characteristics of strain distribution in each part.Based on strain distribution characteristics at the bottom of the top pillar of stope and compared the results of the numerical simulation with mechanical simplified models calculation,the simply supported beam was confirmed as the optimal mechanical simplified models of the top pillar of stope.Combined with the practical situation of mine production,a thickness of 17.5m and a span of 15 m about the top pillar of stope were determined.According to its force condition,the reserved pillar of slope protection can be simplified into two kind of composite beam models.And established the pillar of stope protection’s finite element numerical calculation model to simulate the characteristics of strain distribution in each part.Based on the characteristics of strain distribution at the inclined surface of the pillar of stope protection and compared the results of the numerical simulation with mechanical simplified models calculation,the composite beam model of left hinged and right fixed was confirmed as the optimal mechanical simplified models of the pillar of stope protection.Combined with the practical situation of mine production,a upper width of 20 m about the pillar of stope protection were determined.Selecting the typical geologic sections of the safety pillar at western district in Chengchao Iron Mine and established their numerical model and similar model about the mining at the filling area.to simulate the characteristics of strain distribution of the top pillar of stope and the pillar of slope protection when the safety pillar of typical stope was excavated.Compared the results of numerical simulation and similarity test with the optimal mechanical simplified models calculation,the research show that the result of the simply supported beam about the top pillar of stope and the composite beam of left hinged and right fixed about the pillar of slope protection agree with that of the numerical simulation and similar simulation.