Abstract: Numerical calculations with FLAC3D had been done to establish the three-dimensional numerical model of nuggets recovery process in Nanminghe Iron Mine，and set up the stress-strain monitoring of different rock positions.Analyzed the three-dimen-sional macroscopic mechanical properties of rock under the conditions of 8 m and 10 m two kinds of structural parameters of the ore blocks during the different extraction times.By comparing the mechanical characteristics of rock mining area，the mechanical characteristics of filling and the deformation and destruction of rock，optimized the structure parameters of ore block and determines whether to locate permanently pillar.The results showed that the stability conditions of rock were much better when using the structure parameters of 8 m wide slope than using the structural parameters of 10 m wide slope.When ore recovery mining without reserving the 3 m wide strip pillar filling，the roof only appeared a minor settlement，and would not appear the phenomenon of large-scale caving.

Key words: Nuggets recovery, Numerical calculations, Structural parameters of slope