Three‐Dimensional Modeling of Tailings Beach Shape

Abstract

Abstract: Tailings (mining waste) disposal is a significant consideration for the mining industry, with the majority of the ore processed in most mining operations ending up as tailings. This creates large volumes of tailings, which must be handled and stored responsibly to avoid potential environmental catastrophes. The most common form of tailings storage facility is the impoundment, where tailings are contained within a basin, with beaches forming around the perimeter of the impoundment and a pond standing in the middle. A relatively new method of tailings storage is to create a “stack,” whereby the tailings solids form a large heap, with the discharge of tailings slurry from the apex of the heap. This method of tailings storage is finding greater popularity as the industry seeks to reduce the amount of water discharged with the tailings, and usually features the discharge of non‐segregating tailings slurry that flows turbulently in its own self‐formed channel down the tailings beach. It is of significant interest for mine operators and tailings engineers to be able to predict the shape of the beach that forms in either of these disposal scenarios. The key to being able to do this relies on a method of prediction of the beach slope. In this article two new beach shape models are presented for the three‐dimensional (3‐D) geometric modeling of the beach surface of a tailings stack that has been formed through the variable discharge of a non‐segregating slurry that periodically changes in its composition, whereby the overall discharge output is defined as a sequence of smaller finite periods of steady uniform discharge, each having its own resulting beach slope. A beach slope model previously presented by the authors has been used here to predict the applicable beach slope for each finite discharge regime. The shape models presented here present two different methods for the compounding of the individual tailings deposits that are generated by each of these finite discharge regimes. Historic tailings discharge data is run through both models, and the shapes predicted by the models are compared with aerial survey data of real tailings stacks. This work not only presents a method of tailings stack shape prediction, but also a plausible theory for explaining the concavity of tailings beaches. The models also have the potential to be developed further for the 3‐D modeling of tailings beaches formed in other types of storage facilities, such as impoundments or valleys.