Mine waste characterization through integrated synchrotron and geomicrobiological approaches

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Mining is a big part of Canada's economy, but it also brings us major environmental challenges, including water and soil contamination, disruption of biological systems, and accumulation of voluminous and often toxic mine tailings. Bacteria can cause major problems and major benefits in mine waste management: they can lead to release of toxic elements such as arsenic from rocks, and conversely they can control and prevent release of toxic elements into the environment. It is very important to understand what bacteria are present in a given mine waste, and how they will influence the chemistry of toxic elements in that waste over time. To complicate matters, some bacteria can create microenvironments: tiny niches where the bacteria generate chemical conditions that are very different from the rest of the waste. These microenvironments can have an important influence on the overall chemical stability of toxic elements. Sometimes the bacteria in these niches are relatively rare in numbers, making them difficult to see even with specialized genetic tools - but they can still have a big impact on the waste chemistry. Thus, it is important to study microbially-generated microenvironments, since they could have major implications for how mining companies responsibly manage their wastes. **To address this research challenge, I have planned a collaborative and interdisciplinary research program for my students. Our study system will be microenvironments in uranium mine tailings and waste rock from northern Saskatchewan. We will use synchrotron imaging methods to map out the elements and minerals in our samples, and create conceptual models of how microbes may be controlling the chemistry we observe. We will take these models and use them as a map to help us explore the microbiology of the microenvironments: we will use genetic data to take a microbial census; we will culture, isolate, and study the bacteria that prefer the conditions present in the microniches; and we will aim to re-create the microenvironments in artificial systems in the lab using the isolates from the mine waste samples. Finally we will take our findings and develop a more detailed conceptual model. The model will incorporate our new understanding of what bacteria are present in the mine wastes, what their role is in creating microenvironments, how they impact elemental transformations in the microenvironments, and what the implications are for the overall stability of the mine wastes. The ultimate goal of the research program is to improve sustainable mining practices by helping Canadian mining companies understand and harness the power of the billions of microbes present in their wastes, and to help keep our environment clean and safe for the future. **As part of this program of research, I will train students in cutting-edge skills in microbiology, geochemistry, and synchrotron-based spectroscopy. Students will have opportunities to develop industry and academic collaborations during their studies. I will prepare HQP for employment in the mining and energy sector by providing them with skills training in communications and project management, and they will also be given regular opportunities to network with potential employers during the program. This research program also offers a unique opportunity for students to base their training at the Canadian Light Source, and thus benefit from the highly multidisciplinary and dynamic environment present at this facility. As future leaders in industry, academia and regulatory bodies, students trained in this program will be positioned to understand the power of incorporating microbiological and synchrotron tools into strategies for addressing some of Canada's most challenging environmental problems.