Mine waste and tailings represent both long-term environmental liabilities and untapped sources of critical minerals and materials. This lecture focuses on microbially-driven bioleaching as a transformative approach to recover value from mine waste while advancing zero-waste mining solutions. By leveraging targeted microbial metabolisms, valuable metals can be selectively mobilized from low-grade or legacy materials, reducing toxicity and supporting environmental remediation. The integration of genomics technologies has improved our ability to identify and control microbial catalysts, overcoming previous barriers to large-scale application. A critical focus of this growing field is on piloting and scaling these technologies under real-world conditions to accelerate commercialization and reduce technical and financial risk. Attendees will gain a better understanding of the use of cross-disciplinary approaches combining microbiology, geochemistry, and engineering and see a few use cases that illustrate a viable approach to zero-waste and circular mine waste management. Canada is very well positioned to create economic opportunities from waste while strengthening the domestic supply of critical minerals in alignment with clean energy transition goals.

Sulfur compounds capable of oxidation, e.g., thiosalts (SnOx2-), are common by-product of operations processing sulfide minerals. They remain a global mining environmental challenge linked to impacts such as ARD and toxicity failures; indicating biological knowledge gaps contribute to on-going sulfur risks. Case study results of a 5-year sulfur biogeochemical investigation of four Canadian base metal mine tailings impoundment (TI) and receiving environment (RE) waters, reveal extensive microbial sulfur cycling directly linked to acidity and reactive sulfur outcomes.  Identified conditions and controls on these microbial sulfur oxidation reactions are not captured in current model and management strategies, underscoring the need for biogeochemical investigation to improve sulfur related RE outcomes.  Attendees will gain a biologically informed perspective in this lecture that will demonstrate how such microbially integrated investigation addresses long-standing critical sulfur knowledge gaps, and paves the way for development of smart, nature-based sulfur solutions.