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.