Publications

Back-analysis of an inter-ramp scale failure in the south wall of the Rosario Pit – Cia. Minera Doña Inés de Collahuasi

E.A. Santander, M.I. Riveros & I.T. Smoje

ABSTRACT: In May 2006, an instability involving five benches occurred in the south wall of the Rosario Pit. The failure did not cause injuries to mine personnel nor damage to equipment, but it did generate delays in achievement of mining developments and it also jeopardized the stability of the main access ramp to the pit bottom. The failure mechanism was established at the inter-ramp scale and mitigation measures included unloading of the wall starting in the first bench affected from the top of the slope. The complex failure mechanism was evaluated using kinematic analyses, limit equilibrium tools (SLIDE) and discontinuum numerical modeling tools (UDEC). The failure mechanism is combined; planar in the upper benches (involving the “Última” Fault, which contains montmorillonite infillings) and staggered in depth, generating a curvature of the failure surface towards the floor of bench 4510, where the rock mass quality is poorer and the structural patterns dip into the pit. The back-analysis allowed estimating residual properties for the structures involved in the instability, thus leading to geotechnical recommendations resulting in the reduction of the geotechnical hazard on the South ramp and a redefinition of the future pushbacks in the area.

Available in Continuum and Distinct Element Numerical Modeling in Geo-Engineering - 2008

Return to List of Papers