Farmed tailings stacking

Authors: Li, H; Hinton, J; Navarro, J Download Paper Open access courtesy of:

DOI https://doi.org/10.36487/ACG_repo/2455_15

Cite As:
Li, H, Hinton, J & Navarro, J 2024, 'Farmed tailings stacking', in AB Fourie & D Reid (eds), Paste 2024: Proceedings of the 26th International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 193-198, https://doi.org/10.36487/ACG_repo/2455_15



Abstract:
Recent catastrophic high-profile tailings dam failures such as Fundão and Brumadinho have regenerated interest in tailings dewatering and dry stacking as risks of catastrophic failures or runout associated with wet tailings disposal or conventional tailings storage facilities are dramatically reduced or totally eliminated. Dry stacking is normally achieved using filtered tailings which has low moisture content and cannot be pumped. Filtered tailings is generated by high-rate thickeners followed by filtration. An alternative method to filtered tailings is to dewater tailings and accelerate consolidation in situ through mud/tailings farming, especially in regions where evaporation rates are high and rainfall is relatively low. Mud farming is not a new technology and has been applied in the alumina industry for decades. It can be used to generate tailings with solids content as high as those that can be achieved by filtration and create structural zones for safe and stable tailings storage facilities. The method requires low capital and operational expenditure, substantially less than that required by the filtration process. This paper presents an alternative approach for dry stacking using farmed tailings. Key aspects for farmed tailings stacking, including water management, tailings farming, and disposal area/tailings cycle time are discussed. Water management is to ensure the decant pond in a tailings storage facility is minimised such that tailings in the structural zones can be farmed at all weather conditions. In order to achieve required tailings density and strength in the structural zones for safe and stable facilities, proper farming equipment, methodologies and assurance are needed and tailings cycle time between two consecutive tailings depositions should be adequate for tailings air drying and farming. In this stacking, dam safety relies on the farmed tailings in the structured zones and thus, only small bund walls are required for tailings containment and surface water management.

Keywords: mud farming, filtration, tailings stacking, tailings, water management

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