Simms, P, Sivathayalan, S & Daliri, F 2013, 'Desiccation in dewatering and strength development of high-density hard rock tailings', in R Jewell, AB Fourie, J Caldwell & J Pimenta (eds), Paste 2013: Proceedings of the 16th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 75-86, https://doi.org/10.36487/ACG_rep/1363_06_Simms (https://papers.acg.uwa.edu.au/p/1363_06_Simms/) Abstract: The time for a freshly deposited layer of high-density tailings to reach a given water content and the contribution of desiccation to the geotechnical behaviour of the stack are complementary pieces of information. Generic modelling analyses to predict dewatering time, first presented at the 13th International Seminar on Paste and Thickened Tailings in 2010 (Paste 2010), are compared with a laboratory simulation of multilayer deposition and select field data. The multilayer experiment supports the finding of the generic modelling predictions: the rate of dewatering decreases over time, as evaporation can be supplied by water from the underlying pre-desiccated tailings. Geotechnical behaviour is discussed using results from simple shear and vane tests on samples with different degrees of desiccation and different levels of subsequent consolidation. Desiccation appears to substantially increase strength and imparts strain hardening behaviour to tailings even after they are re-saturated and consolidated. Substantial increases in strength occur well before the shrinkage limit is reached. Finally, the relevance of shear strength development to overall stack geometry and beach angle is briefly discussed.