Jayasiri, N, Fourie, AB & Vulpe, C 2024, 'A comparative study on the performance of electroosmotic consolidation of fluid fine tailings under constant voltage and constant current configurations', in AB Fourie, M Tibbett & G Boggs (eds), Mine Closure 2024: Proceedings of the 17th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 905-920, https://doi.org/10.36487/ACG_repo/2415_65
(https://papers.acg.uwa.edu.au/p/2415_65_Jayasiri/)
Abstract: Accelerating the consolidation of fluid fine tailings plays a key role when it comes to mine closure, particularly due to the challenges associated with placing the capping layers. While there are several conventional practices in the industry to enhance consolidation, these techniques are sometimes only moderately effective, or impractical. Consolidation by means of electroosmosis (EO) offers a promising approach for the treatment of slurried tailings in the context of safely closing tailings storage facilities. This technique involves placing a series of electrodes into the ground and applying an electrical potential difference between the electrodes to induce water molecules to move towards the negatively-charged electrode from the vicinity of the positivelycharged electrode. Here, the electroosmotic force which drives the water flow through soils can be generated by either applying constant voltage with a variable current or a constant current with variable voltage. Although numerous studies have been conducted using both aforementioned approaches, to the authors’ knowledge a comparison of these approaches focusing on dewatering and the strength gain aspects of fluid fine tailings has not been carried out. In this study a series of laboratory-scale experiments were carried out to evaluate the performance of EO consolidation of fluid fine tailings under constant voltage and constant current configurations. The results show that in contrast to the constant voltage approach, the constant current mode produces superior outcomes in terms of dewatering at a higher and more sustained rate, but at the expense of higher power consumption. The outcomes of the study also suggest that dewatering under constant voltage configuration maintains a constant dewatering rate for the majority of the test period owing to the high initial moisture content and high conductivity characteristics of fluid fine tailings. The implications of these findings in improving the economic viability of EO treatment of tailings prior to final cover placement are discussed.

Keywords: consolidation, electroosmosis treatment, tailings dewatering, mine closure, fluid fine tailings