Buckley, RS & Spagnuolo, EK 2024, 'Techno-economic assessment of underground mine dewatering systems ', in P Andrieux & D Cumming-Potvin (eds), Deep Mining 2024: Proceedings of the 10th International Conference on Deep and High Stress Mining, Australian Centre for Geomechanics, Perth, pp. 1481-1494, https://doi.org/10.36487/ACG_repo/2465_97 (https://papers.acg.uwa.edu.au/p/2465_97_Spagnuolo/) Abstract: To meet the global demand for minerals, Canada will need to develop new underground mines, deepen existing underground mines or convert open pit operations to underground mines. Dewatering systems will need to be implemented to handle the water encountered when going underground, which is typically generated from natural fissure water, rainfall ingress, rapid ice melts and mine service water. Many designers of operations, when designing their dewatering system, do not holistically look at the overall life of mine costs associated with said system. The Hydraulic Institute and Europump therefore developed a lifecycle cost (LCC) calculator in order to quantify all the associated costs. This paper will illustrate the use of the LCC calculator to conduct a techno-economic assessment of the three main dewatering systems as seen in industry, namely: cascading, single lift utilising in-line multistage pumps and opposed impeller multistage pumps. For each of the three systems, this paper will expand on the technology by way of their features, performance and maintenance requirements. For the purpose of this analysis, a theoretical underground mine with a pump station located 500 m below surface, and dewatering at a rate of 460.8 m³/h, was used. The results of the techno-economic assessment showed that a single-lift system utilising the opposed impeller configuration multistage pump technology has the lowest lifecycle cost over a 15-year period, which in turn resulted in the lowest rate per cubic metre dewatered. Keywords: Mine dewatering systems, opposed impeller multistage pumps, lifecycle cost calculator, dirty water pumping, techno-economic assessment