Hahn, J 2024, 'How tailing characteristics affect capex and opex in filtration: two case studies', in AB Fourie & D Reid (eds), Paste 2024: Proceedings of the 26th International Conference on Paste, Thickened and Filtered Tailings, Australian Centre for Geomechanics, Perth, pp. 105-114, https://doi.org/10.36487/ACG_repo/2455_07
(https://papers.acg.uwa.edu.au/p/2455_07_Hahn/)
Abstract: The treatment of tailings is increasingly becoming the focus of discussion and decision-making in mining operations. Safety hazards, environmental risks and freshwater consumption are the main topics of discussion and most, if not all, of the problems could be reduced if the tailings were dry stacked and the water was recycled back into the process. However, this is not for free and requires significant capex and opex.
Many experts consider filtration with filter presses to be the solution when it comes to enabling dry stacking. From a process perspective, there is nothing wrong with this answer. However, the capex and opex of filter presses are the highest compared to most other options. For the South American mega tailing projects with capacities of 100,000–200,000 t/d and above, the capital expenditure for filter presses exceeds EUR 1 billion.
It is therefore important to take a closer look at a range of filtration equipment options for safe dry stacking.
The paper presents two case studies with different outcomes and discusses the reasons for the differing results. Case study 1 is for a ‘fine’ tailing with 35 %w/w < 10 micron and requires pressure filtration to achieve the moisture required for dry stacking. Case study 2 is for a ‘coarse’ tailing with 15 %w/w < 10 microns. High performance vacuum disc filters already achieve the moisture required for dry stacking. Switching from filter presses to high performance vacuum disc filters already reduces capital costs from over EUR 1 billion to less than EUR 0.3 billion as shown in case study 2.

Keywords: tailings filtration, vacuum disc filter, high performance vacuum disc filters, TSF, backfill, dry stacking, moisture, filter press, capex, opex