Abstract: Sijiaying Iron Mine is the mine with complex hydro-geological conditions. To ensure the mining safety and protect the local hydrological environment of mine, the back-filling mining method was adopted to realize the annual capacity of 20 million tons of iron ores. There exist abundant Quaternary aquifers in the surface of southern district of the mine. The optimal design model is established in this district by the orthogonal numerical experiments of seepage-stress coupling. Through numerical simulation and optimization analysis, the effect of underground mining on the surface movement and the seepage field are revealed. For the back-filling method in southern district, the ground deformation can be controlled within the allowable range by adopting the mining structural parameters and filling strength obtained above. Amounts of potential water inflow mainly occurred in -450 m and -350 m section, which must be controlled by taking safety precautionary measures to avoid the water inrush disasters in stope.

Key words: Backfill mining, Orthogonal experiment, Optimized mode, Coupling of seepage and stress, Numerical Simulation