Abstract: Aimed at the serious condition of ground pressure disasters, such as rock burst and roof caving, appeared in Hongtoushan Copper Mine, acoustic emission (AE) monitoring technique was used to assess the rockmass stability during mining process in the deep stope, and the duration time of rock mass retraced to the stable state after blasting and the spatial distribution characteristics of AE signals were emphatically studied. The results show that AE activities suddenly jump to a higher level after the blasting, and decrease gradually with time going on. Additionally, a linear relationship is found between the duration time of rockmass retraced to stable state and the distance of monitoring area from blasting position. In the zone over 35 m from the blasting position, AE activity can be recoverd to stable state within 90 minutes after blasting, while in the zone within 20 m from the blasting area, the duration time of AE back to the initial background activity needs more than 2 hours. Moreover, AE events are mainly concentrated in the roof and side walls, and the spalling is more serious in the slope ramp.

Key words: deep stope, rockmass stability, acoustic emission, monitoring