Based on the global positioning system(GPS) monitoring data from 2003 to 2008

tendencies of general deformation of the open-pit

No.1 Mine of Jinchuan Nickel Mine

are analyzed and compared according to spatial and temporal distribution; ground subsidence and horizontal displacement features of the mine area as well as the subsidence and horizontal displacement characteristics of the prospecting line varying with time are obtained. Deformation laws of rock mass due to transform from open-pit to underground mining in high stress area

where horizontal tectonic stress is dominant

are studied in comparison with deformation rules of the open-pit of transition period; theoretical analysis and numerical simulation are introduced to explain the reason of the difference. The results are conducive to understand the characteristics of rock mass movement and failure caused by transition from open-pit to underground mining and to guide safe production in mine area.