SRK Chile’s rock mechanics team completed a study of the slope design at the El Romeral pit located 463 km north of Santiago. Pushback 5 is prolonging the extraction activities carried out at the El Romeral iron ore mine, extending its life of mine to 13 years through the expansion of the Cerro Principal pit.
A comprehensive geological, geotechnical and structural characterisation programme was developed to update the geotechnical units, structural model and geotechnical block model. A conceptual hydrogeological model also was updated with the latest information to incorporate a pore pressure field in the slope stability analysis.
With the experience at the El Romeral pit, the design of the future planned pushback 5 can be carried out with considerable confidence. Back-analyses play an important part in verifying the confidence of design.
As part of the slope design programme and slope optimisation for the pushback 5, the past performance of the pit slopes was evaluated to assess the future pit expansion and potential interaction with historical underground workings. A series of geotechnical studies was performed to analyse slope stability, based on limit equilibrium methods, finite element 2D numerical models and discrete element 3D numerical model (3DEC). A sophisticated mesh using Griddle software was used to incorporate old open stopes and production drifts next to the north wall.
