Slope stability and rockfall Hazard analysis in open pit zinc mine

Abstract

Rockfalls are a major safety hazard in open cut mines, particularly in large-scale deep pits. The geotechnical design relies on in-situ, site-specific, rock slope data to predict the trajectories and velocities of rockfalls that present a residual hazard in the mines. This paper presents slope stability analyses using both static general limit equilibrium methods and finite element stress analyses to estimate unstable areas and slope displacements in the mid-west slope at Glencore Zinc's Handlebar Hill Open Cut mine at Mt. Isa, Queensland, Australia. A conventional program -RocFall- was used for the slope rockfall risk assessment. Results indicate the possible slope benches involved in the initiation of rockfalls, and the maximum run-out distance, which could be defined as the pit's hazardous zone. A rockfall restraining system to absorb the impact energy of boulders and prevent them further falling was also modelled.