Tailings management facility topography modelling to identify flow accumulations and pond geometry

Abstract

Water management is one of the key parameters influencing the stability of a tailings storage facility. Most conventional impoundment failures have occurred because of incorrect water management leading to loss of freeboard and eventual overtopping. These events normally occur during or after storms or when there is a rapid ingress of water into the impoundment (e. g. upstream snow/ice melts). For conventional tailings facilities with uneven beaches a rise in the supernatant pond can cause localised freeboard loss increasing the risk of overtopping. Attempts have been made in the past to try and model the surface of a tailings facility mainly by using photogrammetry and LIght Detection And Ranging (LIDAR). For thickened and paste storage facilities the low elevation areas of the deposit can be determined to establish future discharge flow paths, areas of acid generating tailings that require cover and the current volume of the tailings that are currently stored. This paper presents a realistic technique that can be used on conventional, thickened and paste tailings facilities to model the topography and accurately determine water and tailings volumes. Using Geographical Information System (GIS) software a conventional tailings impoundment can be modelled to determine available water storage volumes and the areas that have the lowest freeboard and are more susceptible to overtopping.