Case Studies in Deeply Weathered Deposits

Abstract

The bench slope performance of transition zone materials in deeply weathered deposits are highly variable due to the inherent soil and rock masses complexity, and the excavation practices that are utilized to form these slopes. For the most part, the transition materials are difficult to characterise due to their geologic variability and preferential weathering processes. Additionally, the early characterisation of these materials is often carried through to the slope design and implementation.

This paper presents an evaluation of the geotechnical parameters that are used to characterise the transition zone materials at the study phase and then refined during pit exposure. Geotechnical characterisation and bench slope performance aspects have been detailed using case study examples from operating mines. In addition, the controlling factors on transition bench slope performance has been reviewed and back-analysed using bench-break break probabilistic techniques.