This bulletin provides a framework for classifying different types of tailings based on their geotechnical properties and provides typical geotechnical parameters for the different tailings types. It also presents technologies for dewatering tailings from thickening to filtration.
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.
Paste thickening represents a proven and effective method for the safe disposal of tailings and maximises water recovery. The optimum density for disposal is often at the limits of that achievable in commercially available thickeners. This paper looks at the options available to increase paste density to meet the disposal requirements and to stabilise paste properties through blending filtered tailings with thickened tailings, supported by experimental data and case studies.
Filtered tailings technology has been successfully implemented only at a limited number of relatively lowproductionrate mining operations. The technology, however, may be poised to make a dramatic leap forward as it is being proposed for use at several high-throughput operations. Demands from increasing regulatory scrutiny and decreasing water availability are likely to drive further adoption of the technology. This paper presents a recommended approach to select a tailings disposal method and summarises several filtered tailings design concepts and considerations that the author has found useful in his practical experience.