A key part of Teck’s water stewardship work is to evaluate and implement new water management and water treatment solutions to protect water quality at our operations. The Cedar North Suboxic Zone Trial in the Elk Valley supports that objective through the assessment of an innovative water quality management approach that prevents unwanted substance from being released in the first place.
Water quality is influenced by how minerals react once exposed to atmospheric conditions and water in while in rock stockpiles. Water quality management through ‘source control’ focuses on design alternatives that prevent unwanted compounds from entering the watershed at the source, as opposed to treating water to remove substances after they’ve been released.
One potential way to implement source control is through purpose-built suboxic zones (SOZ), or areas within a mine rock stockpile where oxygen concentrations are substantially lower than atmospheric oxygen concentrations. By decreasing the oxygen concentration in the pile, the rock will react less and release less of substances like selenium. The development of SOZs within rock stockpiles also allows for purpose built fine-grained layers within the stockpile. These layers support microbial communities that can remove selenium and nitrate from water (similar to Teck’s proven saturated rock fill technology).
By lowering the reactivity of the rock and having an internal process to remove any constituents that do get released, these rock stockpiles have the potential to result in significantly improved water quality when compared to historically constructed stockpiles.
Building mine rock facilities with suboxic zones could be an important step to minimize water quality impacts. Construction of this industry-leading full-scale trial began at Elk Valley Operations in August 2021 and was completed in October 2022. The SOZ is being studied to understand the differences in performance associated with different waste materials and placement procedures. If successful, the next step will be determining how to integrate suboxic zones into future mine rock pile designs.
Performance monitoring of the full-scale trial is currently ongoing, with the first performance monitoring report submitted to the B.C. Ministry of Energy, Mines and Low Carbon Innovation on March 31, 2023.
Ongoing monitoring of the Cedar North SOZ early performance data continued throughout 2023, as Teck continues to research proactive and innovative approaches to source control to further advance efforts to manage water quality at our operations.
Read more about our approach to Water Stewardship on our website.
