Comparison of methods for estimating volume of failed wedges

Author(s): 
William Gibson and Justine Paul
Date: 
Monday, May 9, 2016
First presented: 
Published by SRK, 9 May 2016
Type: 
Article
Category: 
Geotechnical

In open pit mines, bench and berm design plays a critical role in minimising kinematic failures and reducing and controlling rockfalls.  Where kinematic failure mechanisms and rockfall risk—rather than rock mass failure—are the dominant controlling factors for slope failure, benches and berms must be designed according to the specific requirements of different rock types and pit sectors, which in turn impacts inter-ramp and overall slope angles.  It is therefore critical to design benches and berms as accurately as possible, and determining appropriate berm widths (also known as spill or catch berms) is a key factor.  Berms must be wide enough to contain any material falling from the bench faces above, so when designing a berm it is essential to identify potentially unstable wedges and to calculate the likely volume of failed material.

Feature Author

William Gibson

William Gibson has over 30 years’ experience in geotechnical, mining and civil engineering projects as well as in development of computer programs.  His expertise in open pit mining includes slope stability analysis for Chuquicamata, Esperanza and Pelamberes (Chile), Olympic Dam (Australia) and Oyu Tolgoi (Mongolia).  He has expertise in the analysis of interaction between open pit and underground mining operations.  William’s experience in underground mine design includes analysis of block caving mines, mining sequence, open stoping, stability of pillars and interaction of block caving operations with mine facilities.  William is experienced in the analysis of static and seismic conditions, having undertaken seismic risk assessments in parts of South and Central America and Canada.  His computer programming experience includes finite elements and discontinuous deformation analysis programs; and programs for rock fall 3D analysis (RFall_3D), probabilistic wedge stability analysis (MWedge_P), rock mass strength assessment and gravity flow analysis (MFlow) and generation of artificial earthquakes for dynamic analysis (Crono). 

Principal Consultant (Geotechnical Engineering)
MSc (Geotechnical Engineering)
SRK Perth
SRK United Kingdom