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Abstract

Across the world, anthropogenic and natural slope failures occur regularly. Management of slope instabilities and related hazards are an ongoing focus of research within the mining industry. Proactive monitoring and assessments of these hazards comprise a key responsibility of geotechnical practitioners towards the safe design implementation of large open pit mines. Open pit slope failures primarily occur as a combination of structural geology and rockmass strengths, groundwater influence, geotechnical uncertainty, human error and economic necessity. Advancements in monitoring technologies have increased the confidence and overall safety surrounding the implementation of engineering designs, despite some slope failures occurring within slopes explicitly modeled with low probabilities of failure. While confidence has increased, uncertainty remains, particularly regarding real-time monitoring of ‘progressive/regressive’ slope instabilities and systematic alarm frameworks. Literature review of over one-hundred historical slope failures and their associated slope monitoring data presented herein, suggest the continued need for further study of failure characteristics and their associated failure mechanisms, monitoring data, shear strength characteristics of “rock-bridging”, detailed design assessments and governance frameworks. Application and validity of various failure forecasting methods, including Fukuzono (inverse velocity), Onset of Acceleration and acceleration characteristics are explored and discussed in the context of progressive failure mechanisms, the geotechnical conditions necessary for validity, and potential implications towards proactive engineering designs in consideration of slope damage (or fatigue). The following conclusions and recommendations for further study include: • A fully developed, or very near fully developed shear surface, is a pre-cursor requirement for progressive failure, including slope acceleration and inverse velocity forecasting. While this is somewhat obvious, given the current state-of-the-art methods utilized in slope design engineering, the practical implications of this statement may be potentially misinterpreted. • Acceleration alarms, in conjunction with other current state of practice alarm triggers, may allow for the near real-time determination of Onset of Acceleration bounding and failure forecasting. • Periods of slope acceleration, as opposed to velocity or deformation, are believed to encompass the primary duration in which progressive slope failures develop or slope damage occurs. • “Rock-bridging”, or basal plane shear strengths utilized within slope designs, and associated monitoring and slope design practices, warrant significant further research.