Research On Optimization Of Stope Parameters Of Deep Gently Inclined Thin Ore Body And Mining Subsidence Characteristics

When exploiting slowly inclined thin ore body under the building, there often appears large-scale pressure activities because of the unreasonable stope structure parameters and exploit disorders, which triggers serious subsidence deformation of surface and has lost a lot of ore resources. Therefore, mining scheme design based on reasonable stope structure parameters and exploit order is particularly important in stoping. Zinc copper ore body of Tongkeng mine, which is inclined thin ore body, is buried deep and located below the industry plaza and office buildings. This paper bases on the engineering geology survey and indoor rock mechanics experiments, in use of both the theoretical calculation and numerical simulation test to optimize reasonable stope structure parameters and mining sequence, and synthesize scale mining technology and no waste against mining technology to put forward the mining scheme, and then research the surface subsidence characteristics triggered by mining. The main contents as following:(1) Carry out the engineering geology survey work, then master the ore body’ geological characteristics of the surrounding rock, and obtain the ore mechanical parameters through the indoor rock mechanics experiments.(2) Expound the failure criterion of stope engineering, and put forward the destruction criterion of rock mass through the synthesis of commonly used Rock Strength Theory, Permissible Ultimate Displacement Criterion and Plastic Zone Criterion.(3) Construct a numerical model to calculate stope limit exposure area, and combine with Mathew theory to limit of zinc body exposed area as value of900m2in copper mine stope. Then construct the numerical model to optimize the stope structure parameters and mining sequence, the result of which shows that the design in which the distanced of40m in stope tendency length, width of22.5m in stope trend, width of ore pillar as6m, stoping order is from one end to the other along trend and recovery is along the tendency from low to high position is the best design.(4) In usage of both scale mining technology and no waste against mining technology, forward the mining schemes which apply to the exploit on ore body which has characteristics of being buried deep, thin thickness and slow inclination.(5) Use probability integral method and finite element software ANSYS to research the surface subsidence law which triggered by the exploit of copper mining zinc. The results show that mining of zinc copper body will cause a much larger subsidence area on surface than mined-out area, whose biggest displacement and the maximum horizontal displacement of subsidence point both appear at the center just above mined-out area, and its biggest inclination deformation is highlighted on the earth’s surface located on top of mined-out area. In contrast to building destruction (protection) standard in China, evaluate that Zinc copper ore body’s large-scale mining won’t cause surface damage of buildings.