Winsa, M, Petrovic, N & Mohammadi, A 2025, 'Assessment of the tailings settlement and influence on cap design', in S Knutsson, AB Fourie & M Tibbett (eds), Mine Closure 2025: Proceedings of the 18th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-11, https://doi.org/10.36487/ACG_repo/2515_72
(https://papers.acg.uwa.edu.au/p/2515_72_Winsa/)
Abstract: Closure planning and closure design consider the activities and tasks which will enable a facility to behave, in line with the closure objectives, in the short- and long-term. 
The closure objectives are well identified within society and mining industry and they generally cover key issues that need to be included during evaluation of closure planning and design. They include social impact, environmental concerns, structural integrity and stability, landscape design, final land usage, economical implication, etc.
One of the critical issues in achieving the closure objectives for tailings storage facilities (TSF) is related to the behaviour of the tailings within the facility. There are many factors influencing the short- and long-term behaviour of tailings. 
This paper uses broad assumptions based on limited data about tailings properties as homogeneous and simple one-dimensional models to simulate conditions within the Garpenberg TSF influencing the tailings settlement and, finally, on cap design. 
Based on the limited data available at this stage, preliminary assessment of the settlement was conducted using assumptions about the tailings properties and the water levels within the facility. A simplified method for prediction of deformation within a facility (consolidation and settlement) was carried out using a onedimensional model. The software SIGMA/W, which performs stress and deformation analyses of columns (column test), was used to analyse various thicknesses of the tailings within the facility. 
Three components of the deformation were considered: consolidation after tailings deposition, settlement due to changes of water level within the facility and settlement caused by loading of capping layers. They were assessed separately, and final deformation was obtained by superposition of the estimated values. 
In addition, the feasible options for final cap shape are discussed, and so is how to take settlement into consideration during the design.

Keywords: tailings conditions, consolidation, settlement, cap design