Open-Off Cut Excavation of Fully-Mechanized Top Coal Caving Mining Face and Stability Control Technology of Surrounding Rock

In order to solve a high dfficult control problem of surrounding rock in an open- off cut driving process of a fully- mechanized top coal caving mining fac e, the FLAC3 Dsoftware was applied to a numerical simulation on disturbance conditions of surrounding rock in a primary driving ( pilot gateway) and secondary driving ( reaming) of the open- off cut and the displacement and stress features were compared and analyzed. The results showed that the deformation value of the gateway in the primary driving was not high and with the width of the secondary driving increased, the deformation value of the gateway would be continuously increased. The defo rmation value of the roof would be occurred mainly during the secondary driving period. With a high influence of the secondary driving width, a larger width of the secon dary driving would have more deformation of the roof. Therefore, a wide pilot and narrow reaming driving method was provided and the driving method would have a mi n disturbance and failure to the surrounding rock. An industrial trial was conducted in an open- off cut of No. 1901 fully- mechanized top coal caving mining face in Xish ahe Mine and the trial showed that the max convergence between the roof and floor was 98 mm and the driving method could effectively control the deformation and fail ure of the open- off cut surrounding rock.