Grant: Discovery Grants Program - Individual

Context: The contamination of mine waters circulating through mine waste storage facilities is one of the most serious and complex environmental challenges of the mining industry. Since the source of contamination is the oxidation of sulfide minerals upon contact to atmospheric oxygen and water, many reclamation methods aim to hinder the ingress of oxygen to the mine wastes. Implementing oxygen barrier reclamation systems can induce hydrogeochemical changes in the tailings and have major consequences of the evolution of water quality. The evolution of post-reclamation water quality needs to be predicted as precisely as possible to plan adequate water treatment measures and minimize environmental impacts. However, contaminant concentrations are difficult to predict accurately due to a lack of understanding surrounding the extent of the hydrogeological and biogeochemical processes involved following reclamation and their impacts on water quality. This is especially challenging for oxidized acid-generating tailings, as well as for graphite and lithium mines that are increasingly being developed in Canada and worldwide in response to the demand for battery materials. The objective of this proposal is to predict the long-term post-reclamation water quality of mine tailings in the context of a changing climate. Scientific approach: This research will combine extensive biogeochemical characterization of mine wastes, laboratory studies of their geochemical behavior and subsequent water quality evolution before and after reclamation, field assessment of post-reclamation water quality, and numerical modeling. We will use mineralogical and chemical analyses to define the composition of the materials and their evolution. Advanced characterization methods using Raman spectroscopy, synchrotron-based methods, and scanning electron microscopy will be used to gain a profound understanding of the source and fate of potential contaminants in the tailings. Genomic investigations will be performed to gain insights on the microbial involvement to the biogeochemistry of the tailings. The work will be performed by 7 highly qualified personnel: a postdoctoral fellow, 2 doctorate students, 2 master's students, and 2 undergraduate students. Impact: The proposed program will generate original research that will help prevent harmful environmental impacts of mine wastes and improve the social acceptance of mining projects. The better understanding of the post-reclamation water quality provided by this work will help design more effective reclamation scenarios and plan for the necessary water treatment needs, in the context of a changing climate. The program will also expand the application of numerical modeling to a wider set of contexts by considering species that, to our knowledge, are not currently present in the default databases and/or have not been considered and tested before.