Fluid tailings are common to all surface mining operations and are made up of the water, clay, sand and residual bitumen left over when the bitumen is separated from the sand.
Tailings are stored in deposits that help separate the solids from the water, in order for the water to be reused. Reclamation of tailings ponds can be challenging as it can take decades for the fine particles like clay and silt to settle. We develop detailed tailings management plans that incorporate industry best practices to help ensure tailings storage areas are designed for integrity and maintained accordingly. We also ensure ongoing monitoring and have comprehensive emergency response plans in place
At our Kearl operation, our tailings management strategy is to minimize the fluid tailings we produce to ensure timely reclamation to support a diverse and self-sustaining ecosystem. We do this by treating tailings material right away through the use of thickener technology that intercepts the tailings produced by the extraction process and processes them into a paste. This process increases our ability to remove, and more efficiently recycle water, reduce our freshwater requirements, and reclaim our tailings faster.
We continue to progress our “ready-to-reclaim” tailings volumes and currently almost 90 per cent of our thickened tailings material is now in its final resting place and on the trajectory for full reclamation. We anticipate this volume will fluctuate over time depending on the tailings materials being treated and the treatment method.
Imperial is a member of COSIA’s Deep Deposit Working Group, which released a best-practice guide in 2022 for effectively managing and reclaiming deep tailings deposits to a terrestrial landscape. The guide brings together experience and knowledge from across industry developed over the past 50 years. “Deep deposits can be an efficient way to manage tailings and close facilities depending on the specific application and circumstances,” said Paul Cavanagh, Imperial’s Senior Principal Engineer of Global Dam Safety and Earthworks. “This guide allows anyone — particularly new practitioners — to start with the knowledge in the guide, rather than rediscovering lessons we learned 20 years ago.”