Fort McMurray Oil Sands Slurry Wall

A large oil sands mining operation, located approximately 70 km north of Fort McMurray, Canada, required an effective mine tailings management solution to control seepage and comply with regulatory requirements. The site consists of an open-pit mine and associated oil sands processing facilities, with production beginning in 2013 and expanding in 2015 to a capacity of 220,000 barrels per day.

One of the primary challenges was managing tailings seepage from the first in-pit tailings storage facility while meeting constraints related to tailings management, water storage, and dyke elevation. Regulatory approval under the Environmental Protection and Enhancement Act (EPEA) requires all tailings seepage to be contained within a closed-circuit industrial wastewater management system. Additionally, the project had a tight construction schedule, demanding efficient and precise execution of slurry wall construction without compromising environmental compliance.

To prevent tailings seepage into the Pleistocene Channel Aquifer (PCA) and surrounding environment, a soil-bentonite slurry wall was installed as a containment solution. This cutoff wall was designed to achieve a hydraulic conductivity of 1×10⁻⁸ cm/s, ensuring optimal seepage control. The mix design used 100% borrow material, with dry bentonite added to meet permeability requirements.

To meet the tight construction schedule, the team implemented 24-hour, 7-day-per-week operations. The 1,500-meter-long slurry wall was installed using a combination of:

This slurry wall construction approach maximizes efficiency, ensuring precise excavation and structural integrity while maintaining compliance with environmental regulations.

The successful execution of this slurry wall construction project provided several key benefits:

By leveraging advanced slurry wall construction techniques and 24/7 operations, the project team delivered a high-performance cutoff wall that met regulatory requirements while providing long-term environmental protection and efficient mine tailings management.