Whittall, J, Mitchell, A & McDougall, S 2020, 'Runout of open pit slope failures: an update', in PM Dight (ed.), Slope Stability 2020: Proceedings of the 2020 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, Australian Centre for Geomechanics, Perth, pp. 1149-1162, https://doi.org/10.36487/ACG_repo/2025_76
(https://papers.acg.uwa.edu.au/p/2025_76_Whittall/)
Abstract: A Fahrböschung angle versus volume methodology for estimating the runout distance of large open pit slope failures was proposed to the open pit geotechnics community in 2015 (Whittall et al. 2015). Since that 2015 publication, three commonly received questions on the methodology include:
This paper provides a summary of refinements to runout estimate techniques for pit slope failures. In particular, empirical tools for estimating small-volume bench scale failures and a probabilistic framework for spatially distributed runout estimates are provided. A risk assessment methodology is proposed that can be mapped across the pit floor by dividing it into square grid cells and calculating individual risk for each cell. The goal of this paper is to supply practitioners with quick, repeatable tools to better understand the landslide risk to which workers and equipment are exposed, and support decision-making when working in an open pit with a developing or imminent pit slope failure.

Keywords: pit slope failure, runout analysis, exclusion zones, landslide risk management, trigger action response plans