Clarke, R 2025, 'Climate change impacts on the hydraulic performance of pit closures across 
different climatic regions in Australia ', in S Knutsson, AB Fourie & M Tibbett (eds), Mine Closure 2025: Proceedings of the 18th International Conference on Mine Closure, Australian Centre for Geomechanics, Perth, pp. 1-15, https://doi.org/10.36487/ACG_repo/2515_85
(https://papers.acg.uwa.edu.au/p/2515_85_Clarke/)
Abstract: Climate change can pose significant challenges to mine closure planning, necessitating adaptive and forwardthinking strategies. The level of uncertainty surrounding future climate variability has warranted the generation of climate change projections to be challenging in engineering modelling assessments. This paper delves into the methodology of integrating climate change projections into water balance modelling (WBM) to assess the hydraulic performance of mine pits after closure. WBMs – which account for the inflows, outflows, and storage of water in post-mining landscapes – are a typical tool for predicting the hydraulic behaviour of residual voids and other storages over the long term. Emphasis is placed on integrating downscaled climate data into WMBs to improve the precision of rainfall and evaporation parameters, leading to more informed predictions in the future hydraulic performance of residual voids. Results are presented for three hypothetical mining locations each posing different climatic characteristics as defined by Australian Rainfall and Runoff (ARR) guidelines. The regions are Pilbara in Western Australia (hot and arid), Bowen Basin in Central Queensland (subtropical) and Hunter Valley in New South Wales (temperate). The net balance between inflows and outflows varies across the regions and further extreme conditions are anticipated based on projections from global climate change models (GCMs). The model results provide insight into whether the pits will act as water sources or sinks, demonstrating water level fluctuations and the likelihood of overtopping risks. The findings aim to inform future mine closure pit design by evaluating the extent to which climate change will affect pit performance in diverse biomes. The study underscores the need for globally applicable best practices in mine closure planning, focusing on climate-resilient strategies that align with regulatory frameworks and stakeholder expectations. By improving the accuracy of long-term hydraulic performance predictions, site-specific WBMs become essential tools in aiding adaptive solutions for mine closures.

Keywords: climate change, hydraulic performance, water balance modelling, adaptive solutions, extreme conditions, residual void