Abstract: The underground continuous mining technology for low grade orebodies is a method for realizing the high efficiency production of mine, of which the roof control is one of the key techniques. A systematic study is made on the underground continuous mining of No.3 thick and low grade orebody of a nonferrous metal mine by a simulation test with similar material and by FLAC-3D method, including the study on the natural roof caving, the time-sequence system of artificially induced roof caving and the roof stress change law in the mining process. The results show that the initial roof caving space of No. orebody is 96 m and the natural caving property of the roof is poor. Using artificially induced roof caving method, cutting inducing slots in the roof and rationally arranging the time and space sequence between the orebody mining and the roof caving can realize a stepwise caving of the roof in mined-out area with the progress of mining so as to ensure a safety extraction. The roof stress has a tendency to rise with the progress of the mining and will decrease before the roof caving but with not large change amplitude in stress. The study has proved that the underground orebody roof in the continuous mining can be effectively controlled by artificially induced caving technology.

Key words: Roof control, Underground continuous mining, Natural caving property, Artificially induced caving, Time sequence system