Simms, P 2023, 'Unsaturated soil behaviour in thickened and filtered tailings', in GW Wilson, NA Beier, DC Sego, AB Fourie & D Reid (eds), Paste 2023: Proceedings of the 25th International Conference on Paste, Thickened and Filtered Tailings
, University of Alberta, Edmonton, and Australian Centre for Geomechanics, Perth, pp. 663-675, https://doi.org/10.36487/ACG_repo/2355_51
Proper application of unsaturated soils to thickened or filtered tailings has substantial potential to optimise such tailings deposition. Unsaturated behaviour bears on both the geotechnical and geo-environmental performance of these deposits. Geotechnically, there is an increase in strength through both additional densification, and the presence of suction, as well as a stress history effect. The latter is especially important to understand in situ measurements in previously desiccated deposits; geo-environmentally, unsaturated behaviour strongly bears on seepage generation, as well as management or mitigation of acid generation. This paper summarises a body of work on experimentation, numerical simulation, and field data relating to different aspects of unsaturated behaviour and their relevance to practical outcomes for design of thickened or filtered tailing deposits. An important new outcome from this summary is the suggestion to characterise the extent of the stiffness imparted by drying, especially due to the possible risk of strength loss in thick deposits when the tailings eventually yield under self-weight.
Keywords: unsaturated, volume change, dewatering, desaturation, strength, desiccation, drying
Bussière, B 2007, ‘Colloquium 2004: hydrogeotechnical properties of hard rock tailings from metal mines and emerging geoenvironmental disposal approaches’, Canadian Geotechnical Journal, vol. 44, no. 9, pp. 1019-1052,
Daliri, F 2013, The Influence of Desiccation and Stress History on Monotonic and Cyclic Shear Response of Thickened Gold Tailings, PhD thesis, Carleton University, Ottawa.
Dunmola, A, Cote, C, Freeman, G, Kolstad, D, Song, J & Masala, S 2013, ‘Dewatering and shear strength performance of in-line flocculated mature fine tailings under different depositional schemes’, in GW Wilson, DC Sego & NA Bier (eds), Proceedings of the Seventeenth International Conference on Tailings and Mine Waste, University of Alberta Geotechnical Center, Edmonton.
Daliri, F, Kim, H, Simms, P & Sivathayalan, S 2014, ‘Impact of desiccation on monotonic and cyclic shear strength of thickened tailings’, Journal of Geotechnical and Geoenvironmental Engineering, vol. 140, no. 9.
Daliri, F, Simms, P & Sivathayalan, S 2016, ‘Shear and dewatering behaviour of high density gold tailings in a laboratory simulation of multi-layer deposition’, Canadian Geotechnical Journal, vol. 53, no. 8, pp. 1246–1257.
Fisseha, B, Bryan, R & Simms, P 2010, ‘Evaporation, unsaturated flow and salt accumulation in multilayer deposits of a ‘paste’ gold tailings’, Journal of Geotechnical and Geoenvironmental Engineering, vol. 136, no. 12, pp. 1703–1710
Fredlund, DG & Rahardjo, H 1993, Soil Mechanics for Usaturated Soils, John Wiley & Sons Inc., New York.
Fujiyasu, Y, Fahey, M & Newson, TA 2000, ‘Field investigation of evaporation from freshwater tailings’, ASCE Journal of Geotechnical and Geoenvironmental Engineering, vol. 126, no. 6, pp. 556-567,
Heidarian, P 2012, Effect of Initial Water Content and Stress History on the Tailings Water-retention Curve, MASc thesis, Carleton University, Ottawa.
Newson, TA & Fahey, M 2003, ‘Measurement of evaporation from saline storages’, Engineering Geology, vol. 70, no. 3–4,
Qi, S, Simms, P & Vanapalli, S 2017a, ‘Piecewise-linear formulation of coupled large-strain consolidation and unsaturated flow.
I: model development and implementation’, Journal of Geotechnical and Geoenvironmental Engineering, vol. 143, no. 7,
Qi, S, Simms, P Vanapalli, S. & Soleimani, S. 2017b, ‘Piecewise-linear formulation of coupled large-strain consolidation and unsaturated flow. II: testing and performance’, Journal of Geotechnical and Geoenvironmental Engineering, vol. 143, no. 7.
Qi, S & Simms, P 2018a, ‘Hydro-mechanical coupling in dewatering simulations for mine tailings management’, in C Ng, A Leung, A Chiu & C Zhou (eds), Proceedings of the 7th International Conference on Unsaturated Soils, vol. 2, pp. 1157–1162, Hong Kong University of Science and Technology, Hong Kong.
Qi, S & Simms, P 2018b, ‘Analysis of dewatering and desaturation of generic field deposition scenarios for thickened tailings’,
in RJ Jewell & AB Fourie (eds), Proceedings of the 21st International Seminar on Paste and Thickened Tailings, pp. 401–412, Australian Centre for Geomechanics, Perth.
Qi, S, Simms, P, Daliri, F & Vanapalli, S 2020, ‘Coupling elasto-plastic behaviour of unsaturated soils with piecewise linear large-strain consolidation’, Géotechnique, vol. 70, no. 6, pp. 518-537,
Reid, D, Simms, P, Sivathayalan, S, Fanni, Ricardo & Fourie, AB 2022, ‘The “air-dried” specimen reconstitution technique - review, refinements, and applications’, Proceedings of Tailings and Mine Waste 2022.
Robertson, P, Viana de Fonseca, A, Ulrich, B & Coffin, J 2017, ‘Characterization of unsaturated mine waste: a case history’, Canadian Goetechnical Journal, vol. 54, pp. 1752–1761.
Rozina, E, Mizani, S, Malek, M, Sanchez, M & Simms, P 2015, ‘Dewatering in a laboratory simulation of a multilayer deposit of inline flocculated mature fine tailings’, Proceedings of Paste 2015 Cairns, Australia, pp. 81–94.
Simms, P, Grabinsky, M & Zhan, G 2007, ‘Modelling evaporation of paste tailings from the Bulyanhulu mine’, Canadian Geotechnical Journal, vol. 44, pp. 1417-1432.
Simms, P 2017, ‘Geotechnical and geo-environmental behaviour of high-density tailings’, Canadian Geotechnical Journal, vol. 54,
Simms, P, Soleimani, S, Mizani, S, Daliri, F, Dunmola, A, Rozina, E & Innocent-Bernard, T 2019, ‘Cracking, salinity, and evaporation in mesoscale drying experiments on three types of tailings’, Environmental Geotechnics, vol. 6, no. 1,
Simms, P 2021, ‘The role of unsaturated soil mechanics in unconventional tailings deposition’, Soils and Rocks, vol. 44, no. 3,
Wilson, GW, Fredlund, GW & Barbour, SL 1997, ‘The effect of soil suction on evaporative fluxes from soil surfaces’, Canadian Geotechnical Journal, vol. 34, pp. 145–157.