A geometallurgical approach to tailings management

As dewatering technology advances in efficiency to make tailings higher in solids concentration less expensive to produce, a complementary effectiveness in technology selection is required to ensure capital investment realises value during operational implementation. From conceptual studies through to feasibility, good geometallurgical practices can minimise the risk of incorrect equipment selection. A comprehensive geometallurgical program is an iterative process of testing and verification, working with geologists to identify and sample mineralogical and textural differences between ore types, followed by metallurgical testing at various scales through successive campaigns of project development. During early stages of a project, emerging understanding of geological and metallurgical variability should be used to guide sampling such that significant samples are well represented in testing and flow sheet decisions. In later stages of projects and operations, knowledge of relevant variability can be captured in block models and applied to mine plans to support optimal scheduling and advance notice of upside and downside processing risk. Mineralogy and textural contrast are familiar in the tailings geotechnical community, but the alteration of in situ mineralogy and rock textures through mining and processing creates unique challenges for tailings geometallurgy. Just as knowledge of mineral behaviour during primary processing informs metallurgical flow sheet development and ore sampling requirements, so too, the knowledge of mineral behaviour during tailings dewatering and impoundment can guide geometallurgical sampling during project development. The abundance of plastic (clay) minerals and non-plastic mineral content, along with textural features such as ore hardness, provide a starting point for sampling targets and are relatively easy to determine from small sample masses. This paper aims to provide an overview of relevant literature which can assist tailings practitioners’ discussions with their geology and metallurgy counterparts in designing and implementing sampling campaigns.