Harrison, R 2011, 'Tailings treatment and water option study', in R Jewell & AB Fourie (eds), Paste 2011: Proceedings of the 14th International Seminar on Paste and Thickened Tailings, Australian Centre for Geomechanics, Perth, pp. 67-79, https://doi.org/10.36487/ACG_rep/1104_07_Harrison (https://papers.acg.uwa.edu.au/p/1104_07_Harrison/) Abstract: AMEC Minproc conducted a process water option study for a Western Australian magnetite project which is proposed to produce concentrate and direct ship iron ore. With numerous raw water supply and process water management options available, a high-level mass balance model was constructed to develop 105 different scenarios. Using the model, the study firstly compares five tails dewatering methods: conventional thickening, high density thickening, paste thickening, filtration and split conventional thickening/filtration. Then for each tails dewatering method seven sub-options are considered that relate to the process water addition and concentrate filtration. Further to this, three different raw water sources, each with variable chloride chemistry, are incorporated into the analysis. The main constraints to the model are concentrate chloride limit and tails dam seepage chloride limit. Capital expense (CAPEX) and operational expense (OPEX) were then evaluated for each combination to a scoping study level (±40%). The CAPEX and OPEX are used to calculate delta net present costs (relative to the base case) which were ranked to identify the most (and least) attractive options. Semi-quantitative risk ranking was also completed for the tailings options.