Tell us a bit about your background. What brought you to CRC TiME and the field of mine closure and transitions?
My journey started in Chile, where I graduated with my BSc in Geology and started working as a hydrogeologist conducting groundwater management for the mining industry. In 2019, I moved to Australia to pursue my MSc in Hydrogeology. For my thesis project, I studied the geochemical impacts of Managed Aquifer Recharge in Perth in a joint research project between UWA and CSIRO, led by Professor Henning Prommer. This topic made me more and more curious about how hydrological and geochemical processes interact and impact the water quality in hydrological systems. As my interest broadened, I became interested in post-mining pit lakes, where interactions between these lakes and the surrounding groundwater systems can be fairly complex. However, surprisingly there were no existing modelling tools available to quantify the coupled flow, solute and geochemical processes and to predict the long-term water quality evolution after mine closure. My I PhD studies at the University of Western Australia aim to close this gap by developing a novel modelling tool that will allow us to perform more holistic analyses of these problems. I have started to collaborate with Dr Devin Castendyk, a world leader in the simulation of pit lakes, who works for WSP and provides guidance on the needs of practitioners in this field.
My work will help to address the problem that most of Australia’s mines that are now inactive have not been rehabilitated. I am specifically interested in the sites where pit lakes have formed or will form after mine closure, as they often pose severe environmental risks. I have realised that solving these complex environmental problems requires integrating profound scientific knowledge into the development of practical solutions that are required by and valuable for the industry. I believe that being part of both worlds (academia and industry) is essential to making a real impact. That’s why working within CRC TiME is a perfect fit for my goals. Here, I can work on research that is both novel and practical at the same time. I believe CRC TiME’s strong focus on collaborative efforts between academia and industry will help me and others to contribute to create meaningful tools and solutions to mining-related environmental problems, especially in Australia but also in my home country, Chile, where mining has a significant footprint.
What topic are you delving into for your PhD?
For my PhD, I’m exploring the complex relationships between groundwater, surface water, and the biogeochemical dynamics of pit lakes. This may sound technical, but at its core, it’s about finding ways to simulate the water quality of pit lakes in a more holistic manner to guide and optimise their rehabilitation. I am developing an open-source model simulation tool that considers not just water fluxes in surface and groundwater but also their chemical and biological evolution, and a wide range of climate drivers that affect these ecosystems. What really excites me is the potential for this tool to be a resource for anyone working on pit lakes rehabilitation globally. It’s a project that combines my love of research with a very practical application that can make a difference in the communities surrounding these lakes.
Tell us more about how a holistic modelling of pit lakes can help mine closure
Previous pit lake simulations have generally focused on isolated processes and have, most importantly, ignored the hydraulic and biogeochemical interactions with surrounding aquifers. While this deficiency may not play a significant role in short-term simulations, it is likely that for long-term post-closure simulations, this will lead to biased predictions. The model simulation tool that I am currently developing will help us quantify and better understand how the interactions between pit lakes and aquifers impact the water quality evolution of the coupled system. We can use the model simulation tool to predict the water quality evolution of the lakes for different rehabilitation and management scenarios and help to transform the lakes into unpolluted recreational areas, ecological reserves, or even sustainable water resources. Such a modelling tool empowers us to make informed choices while turning potential hazards into valuable assets, thereby protecting both the environment and the nearby communities.
What is the biggest challenge you see in your field?
Probably the biggest challenge for long-term predictions is the fact that we develop and calibrate our numerical models based on often limited data sets, especially when we compare often short time frames where observations have been taken with the long predictive simulation periods required for mine closure. This, and the fact that the physical and chemical system of a “closed mine” typically varies from the system for which the observations were made, introduces significant uncertainty to our predictions. We need to consider this uncertainty in our predictions and in the decision-making process. Quantifying uncertainty is computationally expensive and has traditionally been avoided by practitioners. However, new technologies have arisen to cope with this by using surrogate models that can reproduce the model outcomes from a complex process-based model using simple (and computationally fast) statistical relationships. The success of using these tools is linked to the ability of the original process-based model to reproduce the majority of processes controlling the evolution of the simulated system. Using the holistic tool that I am developing with surrogate models will help address these challenges and give insights into how to define monitoring plans that ensure the reduction of predictive uncertainty. However, accessing databases to obtain data to setup up these benchmark models and test the simulation tool efficiency is another major challenge. This is why CRC TiME and its industry partners are essential for my project, so I can be able to access databases to simulate site cases and enhance the simulation tool.