Review of bearing and instability of multi-pillar in metal mines

A large number of goaf have been left behind by open-stope mining of metal mines,especially the near surface goaf group,which has been one of the most dangerous sources of mine safety. The goaf stability is closely related to the bearing capacity and unstable failure of pillars. The load transfer effect may induce the cascading pillar failure (CPF) of multi-pillar and the collapse of goaf group. This paper reviews the stability evaluation of singlepillar,load transfer and instability mechanism of multi-pillar. The review shows that,few studies focus on the prediction of cascading pillar failure and the load transfer mechanism of multi-pillar. Attention should be paid to the interaction between pillars and surrounding rockmass,so as to reveal the bearing and instability mechanism of the multi-pillar system. The relevant researches of our group about the instability mechanism of the multi-pillar system were introduced in this paper,which can provide references for the prevention and control of large-scale goaf group instability disaster.