Abstract
Sustainable alternatives to long-term management and treatment of mine-impacted water are necessary for managing long-term liability. One such alternative is source control via suboxic zones (SOZs), where mine waste facilities are designed to limit oxygen ingress and the resulting oxidation and release of constituents of interest. A variety of factors need to be considered to develop source control strategies and designs that meet a site’s overall water quality objectives, including the current mine plan and the flexibility available within it, the appropriate project scale, constructability of design options, and predicted performance. Perhaps most challenging of all, a clear definition of success and how that success will be measured over time is critical to project success. Over the past 11 years, Teck Coal has undertaken a series of studies to characterize SOZ development in existing mine rock stockpiles (MRS) in the Elk Valley, and to develop construction methods to promote suboxia in new MRS. These studies have included:
- laboratory studies of the biogeochemical mechanisms driving SOZ development,
- assessment of potential project locations,
- drilling and instrumentation programs to understand the range of existing conditions within mine rock stockpiles,
- material characterization of construction materials,
- modelling studies to assess relative performance of different construction strategies, and
- workshops with mine planning and mine engineering teams to constrain design options within practical limits and site conditions.
From the above work, two SOZ projects have advanced to detailed engineering and construction in the Elk Valley, Cedar North SOZ and Swift North SOZ.