Authors: Shellam, R; Coggan, J

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Shellam, R & Coggan, J 2020, 'Analysis of velocity and acceleration trends using slope stability radar to identify failure ‘signatures’ to better inform deformation trigger action response plans', 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. 227-240,

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Ground strata failure is a major hazard for open pit mines as it has the potential to cause damage to property and can result in multiple fatalities. Slope stability radar (SSR) systems are used to continuously monitor pit walls and they can detect slope deformation to sub-millimetre scales. However, geotechnical engineers may have limited prior data to set the required trigger action response plan (TARP) thresholds. As a result, arbitrary values or data from other sites are often used to signify dangerous deformation rates which can ineffectively trigger alarms. Therefore, the primary aim of this investigation was to identify the failure indicator factors which best inform TARP thresholds at a particular mine site. Data from eight open pit failures from the same mine were analysed and then compared with data from other published failures. A secondary aim was to a develop a database of combined failure events that could be used as a reference to set meaningful TARP threshold levels at other mine sites with similar mining conditions. The study site failure events ranged in size from 200 to 200,000 tonnes, with most failures occurring in the upper part of the slopes within highly to completely weathered rock. Geological and geotechnical characteristics of the rock mass for the observed failure modes were also included in the analysis. Multiple peak acceleration and peak velocity plots were used to determine clustering for the different characteristics investigated. It was shown that as the failure size increased so did the peak velocity, suggesting that larger failures can accommodate higher displacement rates. Analysis of the combined dataset showed a clear positive relationship between failure size and failure mode up to approximately 3,000 t. However, failure events greater than 3,000 t do not appear to have clear grouping by failure size, suggesting that other factors may control the peak acceleration and velocity rates. This suggests that the TARP should consider different trigger thresholds based on the expected failure mode and size. However, the accurate recording of all failure data across sites with additional characteristics such as, Rock Mass Rating (RMR89), GSI, weathering and lithology would enable improved analysis of velocity trends to provide further insights into factors influencing potential failure. It is concluded, that back-analysis of slope instability events using log-acceleration and log-velocity plots can refine thresholds used in TARPs for specific sites with the study site TARP presented. However, the consistent collection, processing and filtering of failure data across sites is required to improve analysis and implementation of findings.

Keywords: slope stability radar (SSR), trigger action response plan (TARP), open pit, slope failure

Arosio, D & Harries, N 2010, ‘Predicting slope collapse using slope stability radar deformation data’, International Society for Rock Mechanics and Rock Engineering.
Bar, N, Parker, R & Thomas, S 2016, ‘Managing landslide risks associated with erosion-driven instabilities using near real-time deformation monitoring systems’, Rock Mechanics and Rock Engineering: From the Past to the Future.
Cabrejo-Lievano, AG 2013, ‘Analysis of failures in open pit mines and considerations of the uncertainty when predicting collapses’, in PM Dight (ed.), Proceedings of the 2013 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, Australian Centre for Geomechanics, Perth, pp. 483‒497.
Carla, T, Farina, P, Intrieri, E, Botsialas, K & Casagli, N 2017a, ‘On the monitoring and early warning of brittle slope failures in hard rock masses: Examples from an open-pit mine’, Engineering Geology, vol. 228, pp. 71‒81, ‌j.enggeo.2017.08.007
Carla, T, Intrieri, E, Di Traglia, F, Nolesini, T, Gigli, G & Casagli, N 2017b, ‘Guidelines on the use of inverse velocity method as a tool for setting alarm thresholds and forecasting landslides and structure collapses’, Landslides, vol. 14, no. 2, pp. 517‒534,
Carla, T, Farina, P, Intrieri, E, Ketizmen, H & Casagli, N 2018, ‘Integration of ground-based radar and satellite InSAR data for the analysis of an unexpected slope failure in an open-pit mine’, Engineering Geology, vol. 235, pp. 39‒52,
Crosta, GB, Agliardi, F, Rivolta, C, Alberti, S & Dei Cas, L 2017, ‘Long-term evolution and early warning strategies for complex rockslides by real-time monitoring’, Landslides, vol. 14, no. 5, pp. 1615‒1632,
Dick, GJ, Eberhardt, E, Cabrejo-Liévano, AG, Stead, D & Rose, ND 2015, ‘Development of an early-warning time-of-failure analysis methodology for open-pit mine slopes utilizing ground-based slope stability radar monitoring data’, Canadian Geotechnical Journal, vol. 52, no. 4, pp. 515‒529,
Farina, P, Carla, T, Intrieri, E, Ketizmen, H & Casagli, N 2018a, ‘Characterisation of a large slope failure in an open-pit mine through the back-analysis of satellite InSAR and ground-based radar data’, Proceedings of the 2018 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, BCO Congresos, Barcelona.
Farina, P, Carla, T, Intrieri, E & Casagli, N 2018b, ‘Identifying ‘signatures’ of slope failure conditions in open pit mines to support the set-up of alarms: a possible workflow’, Proceedings of the 2018 International Symposium on Slope Stability in Open Pit Mining and Civil Engineering, Seville, Spain.
Federico, A, Popescu, M, Elia, G, Fidelibus, C, Internò, G & Murianni, A 2012, ‘Prediction of time to slope failure: a general framework’, Environmental Earth Sciences, vol. 66, no. 1, pp. 245‒256,
Fukuzono, T 1985, ‘A new method for predicting the failure time of a slope’, Proceedings of 4th International Conference and Field Workshop on Landslides, pp. 145‒150.
Harries, N, Noon, D & Rowley, K 2006, ‘Case studies of slope stability radar used in open cut mines’, International Symposium on Stability of Rock Slopes, pp. 335‒342.
Harries, N, Noon, D, Pritchett, H & Bates, D 2009, ‘Slope stability radar for managing rock fall risks in open cut mines’, Rock Engineering in Difficult Conditions, Proceedings of the 3rd Canada–US Rock Mechanics Symposium, pp. 9‒15.
Maton, T 2002, Geotechnical Management at the Martha Pit, unpublished.
Mazzanti, P, Bozzano, F, Cipriani, I & Prestininzi, A 2015, ‘New insights into the temporal prediction of landslides by a terrestrial SAR interferometry monitoring case study’, Landslides, vol. 12, no. 1, pp. 55‒68,
Mufundirwa, A, Fujii, Y & Kodama, J 2010, ‘A new practical method for prediction of geomechanical failure-time’, International Journal of Rock Mechanics and Mining Sciences, vol. 47, no. 7, pp. 1079‒1090,
Newcomen, W & Dick, G 2016, ‘An update to the strain-based approach to pit wall failure prediction, and a justification for slope monitoring’, Journal of the Southern African Institute of Mining and Metallurgy, vol. 116, no. 5, pp. 379‒385,
Osasan, KS & Afeni, TB 2010, ‘Review of surface mine slope monitoring techniques’, Journal of Mining Science, vol. 46, no. 2,
pp. 177‒186,
Read, J & Stacey, P 2009, Guidelines for Open Pit Slope Design, CSIRO Publishing, Australia.
Rose, ND & Hungr, O 2007, ‘Forecasting potential rock slope failure in open pit mines using the inverse-velocity method’, International Journal of Rock Mechanics and Mining Sciences, vol. 44, no. 2, pp. 308–320,
Saito, M 1965, ‘Forecasting the time of occurrence of a slope failure’, Proceeding of the 6th International Conference of Soil Mechanics and Foundation Engineering, pp. 537–541.
Vaziri, A, Moore, L & Ali, H 2010, ‘Monitoring systems for warning impending failures in slopes and open pit mines’, Natural Hazards, vol. 55, no. 2, pp. 501–512,

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