Complex Broken Residual Ore Mining Structure Model And Its Reliability Analysis

Gold mining is not only national strategic resource, but also non-renewable resource. With the decreasing of gold mining resources, and the increasing demand for gold of domestic and foreign markets, residual ore mining is coming into people’s vision. Residual ore mining is mostly around old goaf, and mining faces always adjacent to old goaf or caving zone. Compared to regular mining, residual ore mining has higher risk and technical difficulty. So, it has important significance, to carry out the research of residual ore mining structural model stability and safety parameters of stopes.This paper takes the residual ore mining engineering body as research object, aiming at safely mining. Carried out research of residual ore mining structural model stability and the safety paremeters of stopes. The main research results are as follows:(1)By field investigation, the situations of mining methods and residual ore distribution were clear. Typical areas were selected to build three-dimensional visual models by Dimine software. The models show that the ore veins of ZT5 are located beneath the ridge, and the ore veins are incomplete, uneven distribution and surrounding goaf. The residual ore of ZT8 is thin and distribute along caving area.(2)Three typical residual mining engineering body was selected to build structure models. Model Ⅰ’s single side and upper are adjacent to goaf, Model Ⅱ’s 3 sides and upper are adjacent to goaf, and Model Ⅲ’s single side adjacent to goaf.(3) The integrity index was used to discounte tensile strength of rock. Structure mechanics beam theory and numerical simulation method were used to comprehensively judge the stability of residual ore mining structure models.The results show that modelⅠand modelⅡ are stable, but modelⅢ is unstable.(4) Monte Carlo method and Paloheimo method were used to analyze the reliability of three residual mining structure models, and determine the safety parameters of stopes in residual ore exploration and mining. The results show that,1) modelⅠ. When the designed stope span keep no change, the stope thickness of intended mining area should be ensured more than 14 m. When the designed stope thickness keep no change, the stope span should be ensured less than 29 m.2) modelⅡ. When the cantilever span keep no change, Cantilever thickness should be ensured more than 23 m.3) modelⅢ. When the designed stope thickness keep no change, the stope span should be ensured less than 70 m.(5) Rock weight stress variation was analysed by earth’s surface subsidence monitoring. The results show that, displacement deformation of earth’s surface has stabilized, and rock weight stress has tended to balance, as at September 2013. The accuracy of residual ore mining structure models stability analysis results were verified by experimental mining. The results show that, Model Ⅰ’s experimental mining stope is stable and Model Ⅱ’s rock is in stable condition, but Model Ⅲ’s stope occured failure during experimental mining. The results of residual ore experimental mining are consistent with structure models stability analysis.