Abstract
Slope stability assessment is an essential aspect of mining and civil engineering. In this study, Songwe open-pit mine in Malawi was investigated to establish possible pit slope instability. In performing the analysis, an integrated approach entailing rock mass characterisation, kinematic and numerical methods were applied. Based on rock mass classification system, Songwe Hill carbonatite rock mass is characterised as a good rock but still it possesses numerous random discontinuities that present a complex challenge in geotechnical engineering. Dip 6.0 software was used in carrying out kinematic analysis based on the attributes of discontinuities. The results show that there is a 16% likelihood of planar failure in the divided slope sections of the planned pit. Thus, slope angle optimisation to 41° has been proposed as a counter-measure to minimise the potential risk of planar failure. At the optimised angle, the risk of planar failure could be reduced by 44%. On the other hand, wedge failure was found to be improbable since no joint intersections were found in the critical zone of potential failure. For numerical analysis, finite element code was applied using FLAC3D 5.0 application. The results demonstrate that overall slope angle of 41° would offer a favourable balance between safety and mining economics as mining operations progress to deeper horizons thereby avoiding a costly push back solution due to instability.
Highlights
The results demonstrate that overall slope angle of 41 ̊ would offer a favourable balance between safety and mining economics as mining operations progress to deeper horizons thereby avoiding a costly push back solution due to instability
The major aim of rock mass classification is to provide a common basis for effective communication concerning geomechanical problems that could be associated with the rock mass condition
The method is a result of a combination of observations of the rock mass conditions (Terzaghi’s descriptions) with the relationships developed from the extensive experience gained using the Rock Mass Rating (RMR)-system
Summary
Slope stability assessment is an essential aspect of mining and civil engineering. Despite advancements in the computer-based slope stability analysis, slope instability still poses a major challenge in large mining operations. Read & Stacey [8] highlight that as surface mining operations are expanding and getting deeper, the influence of in situ stresses could be of reckon to slope instability. This compounding effect in slope stability has to be accorded attention as the demand for mineral resources increase to cater for the world booming population
Sign-in/Register to view highlights & summary Sign-in/Register to access full text options 
Free) 
Talk to us
Join us for a 30 min session where you can share your feedback and ask us any queries you have
Schedule a call
