Evaluation of Rock Slope Stability using Flacslope Software: A Case Study of Jolex Open-pit Mine, Bassa, Plateau State, Nigeria

Idowu, K. A. and Benedict E.

Department of Mining Engineering, University of Jos, Nigeria

Keywords: Rock slope, Open-pit mine, FLACSlope, and Factor of safety (FoS)1

Abstract

Throughout the life cycle of an open pit mine, an important component is the stability analysis of the slope. Slope designs in recent years is based completely on ield knowledge while a better approach can be carried out through the safe design of slopes. Slope failure in a mine area can lead to socio-economic catastrophe as well as great safety catastrophe. The failure mechanisms are greatly dependent on local geology, which varies according to location of rock mass. The basic failure conditions are very diverse and complicated. This study undertakes an investigation into the assessment of rock slope stability, employing a dual approach that integrates indings from both triaxial machine tests and FLACSlope software simulations. In the empirical analysis, triaxial machine tests were conducted to discern the mechanical properties of the rock material in question. The obtained results revealed a cohesion value of 24.08 kPa, signifying the material's inherent strength under shear stress, while an angle of internal friction measuring 34 degrees offered insights into the material's resistance to sliding along internal planes. These parameters serve as pivotal inputs for subsequent stability calculations. Concurrently, employing computational methodologies, the FLACSlope software was employed to simulate the rock slope's behaviour under varying conditions. The software generated a spectrum of factors of safety (FOS), a key indicator of slope stability, spanning a range from 2.26 to 1.23. This FOS range was correlated with a corresponding variation in slope angles, encompassing degrees from 35 to 70. The software's capacity to model and predict slope stability under different scenarios serves as a complementary technique to the empirical approach.