Pytel, W 2010, 'Risk assessment of mine tailings/waste surface ponds', in R Jewell & AB Fourie (eds), Mine Waste 2010: Proceedings of the First International Seminar on the Reduction of Risk in the Management of Tailings and Mine Waste, Australian Centre for Geomechanics, Perth, pp. 229-242, https://doi.org/10.36487/ACG_rep/1008_20_Pytel (https://papers.acg.uwa.edu.au/p/1008_20_Pytel/) Abstract: A general approach for risk assessment of surface tailings/waste storage facilities is presented using Event Trees based on typical failure modes. The relevant modes of failure involve either movement of large volumes of material, often in three-dimensions leading to dam breakage and uncontrolled release of the facility content, or to contamination of the environment with no structural failure. This paper focuses on the fact that natural materials are spatially variable and that a proper stochastic representation of this variability is crucial to achieving a realistic understanding of the geotechnical and hydro-geological safety issues. The risk model consists of products and sums of different risks described by their corresponding probabilities and associated consequences, some of which may be mutually correlated.