Abstract: The Paishanlou gold mine mined the orebody outside of open pit mining boundary with non-pillar open stoping method after transferred to underground mining from open-pit.Large-scale continuous goaf were formed，which left behind potential safety hazard to production of underground and ground surface.The monitoring results with RG winLogger showed that there are three or four segments of stable rocks used as caving controlling level.The shape of caving line was speculated based on the shape of borehole caving section and the observation on the caving of tunnel at 350 m.According to the shape of the caving line，the technical measures for roof stability maintenance were proposed including setting "L" shaped pillar，coordinating mining and filling，controlling blasting parameter，adjusting the direction of discharge of tailings.Good effect on maintaining the stability of goaf roof was achieved.It provides theoretical basis to the final measures of filling gradually from the boundary of caving projective line to inside of goaf.

Key words: RG winLogger, Unsteady goaf, Caving line, Filling