Research On Inclined And Medium-Thickness Phosphate Ore Body' Stope Strata Behaviors And The Overlying Strata' Failure Law Of Caving Method

This dissertation takes the second pit as the research object, which belongs to Linhua mining comPany in Yunnan province. A comprehensive research method, including similar material simulation experiment and numerical simulation method (Flac^3D) was used to analyze the feasibility that using Sublevel shrinkage caving method to mine the inclined and medium-thickness phosphate ore-body, then, the deformation and failure laws of the roof region'surrounding rock, and the surface subsidence rule are obtained. The research results verify the technical feasibility of mining method in preliminary design, and also can be used for reference for the study of the similar nonmetal deposit's mining process. The main research work and achieved results of this dissertation are as follow:①Through the measurement of the rock's physical and mechanical properties in the second pit, the physical and mechanical properties of all kinds of rock distributed in the whole mining region are obtained.②Combining the ore's occurrence conditions, structure and mining process of the second pit, based on the similarity theory, a similar simulation experiment was used to study the feasibility that using improved sublevel shrinkage caving method to mine the inclined and medium-thickness phosphate ore-body. The similar simulation experiment results show that: During excavation in the design range (2220 2270m), the overall of model is stability, there's no large-scale subsidence or damage and damage is mainly local caving. For a word, the mining plan in the preliminary design is technically feasible.③Based on the finite element theory, the numerical simulation method (Fast Lagrangian Analysis of Continua, Flac^3D) was used to study the mining process in the second phosphate rock pit. The surrounding rock's stress, displacement, and the law of deformation and failure are obtained. The numerical results is similar with Similar to the model test, it shows that: During excavation in the design range, the overall of model is stability. Preliminary design of the mining plan is technically feasible.