The strength of thickened tailings, under both static and earthquake loads, depends on its state parameter. The state parameter can be measured by cone penetration test (CPT) soundings within an existing impoundment, but that does not help when designing/planning a new storage facility. In particular, there are currently no known laboratory sample preparation methods that can reliably replicate the depositional environment of silt/sand tailings within a tailings area, including the resulting in situ state. These issues are of particular importance in the design of thickened tailings deposits, where often a steepened beach profile results in tailings storage above the crest of containment structures. For such a facility, reliable prediction of the range of states likely to develop is crucial in estimating the stability of the tailing stack. To provide reference and realistic bounds to the range of states observed in practice in thickened tailings deposits, CPT data from publicly available sources and Golder Associates’ project files were collected and analysed to provide an indication of the effects of depositional environment and tailings type on resulting state. This extends previous work by the authors on this topic for conventional tailings.
Keywords: state parameter, cone penetration test, liquefaction
Reid, D & Jefferies, M 2018, 'A geological principle for the density of thickened tailings', in RJ Jewell & AB Fourie (eds), Proceedings of the 21st International Seminar on Paste and Thickened Tailings
, Australian Centre for Geomechanics, Perth, pp. 117-126.
AECOM 2009, Root Cause Analysis of the TVA Kingston Dredge Pond Failure on December 22, 2008, Project Number 60095742, AECOM, Vernon Hills.
Been, K & Jefferies, MG 1985, ‘A state parameter for sands’, Géotechnique, vol. 35, no. 2, pp. 99–112.
Been, K & Li, A 2009, ‘Soil liquefaction and paste tailings’, in RJ Jewell, AB Fourie, S Barrera and J Wiertz (eds), Proceedings of the Twelfth International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 281–290.
Boulanger, R & Idriss, I 2007, 'Evaluation of Cyclic Softening in Silts and Clays', Journal of Geotechnical and Geoenvironmental Engineering, vol. 133, no. 6, pp. 641–652.
Dillon, MJ & Wardlaw, HJ 2010 ‘Strength and liquefaction assessment of tailings’, in AB Fourie and RJ Jewell (eds), Proceedings of the First International Seminar on the Reduction of Risk in the Management of Tailings and Mine Waste, Australian Centre for Geomechanics, Perth, pp. 347–360.
Jefferies, MG, Roberts, BT, Stewart, HR, Shinde, S, James, D & Williams-Fitzpatrick, S 1988, ‘Island Construction in the Canadian Beaufort Sea’, in DJA van Zyl and SG Vick (eds), Proceedings of the ASCE Specialty Conference on Hydraulic Fill Structures, American Society of Civil Engineers, Reston, pp. 816–883.
Jefferies, MG & Been, K 2015, Soil Liquefaction: A Critical State Approach, CRC Press, Boca Raton.
McPhail, GI, Noble, A, Papageourgiou, G & Wilkinson, D 2004, ‘Development and implementation of thickened tailings discharge at Osborne Mine, Queensland, Australia’, in RJ Jewell and AB Fourie (eds), Proceedings of the 7th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth.
Plewes, HD, Davies, MP & Jefferies, MG 1992, ‘CPT based screening procedure for evaluation liquefaction susceptibility’, Proceedings of the 45th Canadian Geotechnical Conference, Canadian Geotechnical Society, pp. 41–49.
Reid, D 2015, ‘Estimating slope of critical state line from cone penetration test — an update’, Canadian Geotechnical Journal, vol. 52, no. 1, pp. 46–57.
Reid, D & Fourie, AB 2014, ‘Assessing the post-liquefaction shear strength of thickened tailings in the design stage - a review and update’, in RJ Jewell, AB Fourie, PS Wells and DV Van Zyl (eds), Proceedings of the 17th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 429–444.
Reid, D & Jefferies, MG 2017, ‘State parameter as a geological principle in tailings’, in GW Ward, DC Sego and NA Beier (eds), Proceedings of Tailings and Mine Waste 2017, University of Alberta, Edmonton.
Robertson, P, da Fonseca, AV, Ulrich, B & Coffin, J 2017, ‘Characterization of unsaturated mine waste: a case history’, Canadian Geotechnical Journal, vol. 54, no. 12, pp. 1752–1761, https://doi.org/10.1139/cgj-2017-0129
Russell, AR & Reid, D 2016, ‘Effects of suction on CPT results and soil classification’, in BM Lehane, HE Acosta-Martínez & R Kelly (eds), Proceedings of the 5th International Conference on Geotechnical and Geophysical Characterisation, Australian Geomechanics Society, Sydney, pp. 521–526.
Shuttle, DA & Cunning, J 2008, ‘Reply to the discussion by Robertson on “Liquefaction potential of silts from CPTu”’, Canadian Geotechnical Journal, vol. 45, no. 1, pp. 142–145.
Yang, H & Russell, AR 2015, ‘Cone penetration tests in unsaturated silty sands’, Canadian Geotechnical Journal, vol. 53, no. 3,