Goaf instability in an open pit iron mine triggered by dynamics disturbance: a large-scale similar simulation

ABSTRACT The stability of concealed goafs in open-pit mines under the influence of blasting disturbances is directly related to successful mining production. Based on large-scale similar simulations, this study steadily analyses the evolution of full-stress/strain and acoustic emission response information relevant to the instability and failure of the concealed goaf under multiple blasting disturbances in an open-pit iron mine. The results show that after three blasting disturbances, a tension-shear dislocation area is formed at the side corner of the goaf. The goaf roof’s vertical displacement exhibits a ‘two-stage increase’ before roof caving. In contrast, the axial stress on the side wall undergoes ‘two-stage pressure relief’ before roof caving. The stress pattern of ‘stretch-unload-compression-shear’ is observed near the free surface of the side angle before roof caving, while ‘two-stage pressurisation’ is observed at the far end of the free surface. This paper delivers a new way of exploring goaf stability under blasting disturbances.