Disposal of tailings and the mining industry perspective: a case study of the Cuiabá Mine

One of the methods that has been studied for the disposal of tailings by the mining industry is dry stacking. Several studies have indicated that the use of filtered tailings is feasible under certain technical and operational conditions. The requirements for deposition, and characterisation of the tailings properties, must be obtained through a wide range of field and laboratory tests. These parameters are key to determining the behaviour of the material during the dewatering process, the optimum moisture content and the maximum density of the tailing cake, as well as the physical and environmental stability of the projected geotechnical structure. The operational aspects related to the handling of the material are also vital to determine the placement of the filtered tailings on the facility. In addition, the advantages with respect to water consumption, reduced and/or flexible stack footprints and geometries, seepage control requirements, closure/reclamation costs and public perception of risk can result in dry stacking being selected as an economically beneficial alternative, particularly if life-of-mine risks and costs are appropriately considered. As with any conventional tailings management approach, careful and diligent planning, engineering and operational controls, quality assurance/quality control (QA/QC), instrumentation and monitoring are required to manage risks and uncertainties. This paper presents the criteria that need to be evaluated in the evaluation of filtered tailings as a business case, based on the experience of the authors developing such projects within the minerals industry.