Abstract:

In order to reduce the loss of underground resources，improve the economic benefit of mine and the safety of production environment，the“three under” mining is paid more attention.According to the “three under” mining exploitation in Jinkouling mining section as the engineering background，using finite difference software FLAC^3D  to build the numerical model of mining，and then study the sublevel open stopping with subsequent mining structure parameters influence on the stope stability of surrounding rock and the deformation of the ground surface.The results show that it is not conductive to the maintenance of stope stability and control the deformation of the ground surface，if  the  panel length is too large and the thickness of top column and column width is too small.Considering the analysis results and the actual mining，reasonable economic situation，the panel length is 60 meters，top pillar thickness is 7 meters and inter column width is 8 meters for the optimal structure parameters，which can effectively maintain the stability of stope surrounding rock，but also can control the surface deformation，providing a certain reference significance for actual mining.

Key words: Jinkouling mining section, “three under&rdquo, mining, numerical simulation, stope structure, parameter optimization