Study On Optimization Of Stope Structure Parameters Of A Phosphorite Pole Tree Section In Yunnan Province

Phosphate ore as a scarce and nonrenewable strategic resource, is an important chemical raw material. How to exploit phosphorus ore resources safely and efficiently affects not only the economic efficiency of enterprise, but also the national strategic reserves of mineral resources and sustainable development at the same time.Dengganshu mine block of a Phosphate mine in Yunnan province intended to adopt the room and pillar mining method. However, considering that some country roads across the surface, so how to design stope structure parameters reasonablely to ensure the stability of stope and then the security of surface roads must be considered and studied. Whether the stope structure parameters are scientific and reasonable has a great effect on ore exploitation rate and security of underground mining operations, and unreasonable stope structure parameters may cause breakage and falling of roof stratum. However, the more serious is that it may spread to surface, cause surface subsidence and damage surface structures and ecological environment.The paper depends on research project, and carried out optimization and study on the stope structure parameters of Dengganshu mine block. The main study work is as follows:(1) Made an survey and analysis on rock mass structural plane of Dengganshu mine block.(2) Finished the uniaxial compression strength, uniaxial tensile strength, shear strength and other physical and mechanical experiment of rock samples, and acquired the physical and mechanical parameters of rock and ore. Applied Hoek-Brown strength criterion to the parameters reduction and got physical and mechanical parameters of ore and rock mass, which can provide basic data for subsequent studies.(3) Combined with the engineering practice, revised the relevant mechanical formula of simply supported beam theory of materials mechanics, thin plate theory of elasticity mechanics and simply supported beam theory of elasticity mechanics. Studied the relationships between the maximum tensile stress or shearing stress in roof stratum and roof thickness and stope span, and the relationship between the ultimate span of stope and roof thickness. Studies show that the maximum tensile stress or shearing stress increase with decreasing roof thickness and increasing stope span, and vice versa. However, the relationship between the ultimate span of stope and roof thickness is direct proportion. According to the rock layer occurrence and distribution of Dengganshu mine block, calculated the ultimate span of stope in different ming depth. (4)Based on the analysis of equivalent width of pillar, and calculated the minimum side length of pillar of different safety factor and mining depth through shape effects, size effects and hard rock pillar strength formula separately. Take the calculated result at a safety factor of1.6as the optimized result of the size of pillar.(5) Based on the theoretic analysis results, applied finite element software ANSYS to establish numerical model. Analysed and verified the rationality of optimized results through numerical simulation.The results show that the optimized results are basically reasonable and reliable,and have certain reference values.