Building An Overburden Waste Storage Area Over A Tailings Pond

Solving a space challenge.

When our oil sands client needed to expand their overburden waste storage area, they faced a space challenge. The solution was to build the storage area on top of an in-pit tailings pond. This solution posed several challenges including total and differential settlement of the dump and underlying tailings, stability of the potentially liquefiable tailings, softening of waste dump due to water ingress, proximity to active in-pit deposition areas, and space constraints. Thurber worked with the owner to improve the foundation of the dump and design the dump to store 50 metres of overburden. The foundation was capped with a 10 m thick track-packed sand layer. A shear key was placed within the first layers of the dump to provide additional shear resistance and self-healing against cracking, among other defenses. Additionally, Thurber provided laboratory testing and design services to assess the critical state behaviour of the underlying tailings and predict the dump's performance under load.