Influence of interface and induced seismicity on overburden dump slope stability

Abstract

A large volume of overlying waste material is removed to access deep-seated mineral deposits and stored near mines or eventually dumped as backfill. Overburden is stored in stacked dumps due to space constraints and high stripping ratios. The height and slope of these overburden dumps are enormous. This study is a para-metric evaluation of the impact of interface and blast-ing-induced seismic loading on the stability of dump structures having total heights varying between 60 and 120 m. The study reveals that for 20° of internal fric-tion of the interface, a factor of safety (FoS) of the slope structure increases with increasing cohesion (10–30 kPa). However, as the friction angle increases from 20° to 25°, the relative increase in FoS is reduced. Thus FoS remains unchanged with increasing cohesion for a fri-ction angle of 29°. The stability of the dump reduces when subjected to blasting-induced seismic loading. The damage is more due to the shock waves imposing seismic loading in the horizontal direction than in the vertical direction.