Performance Of Mine Waste Earth Fill Dumped Into Deep Standing Water

ABSTRACT: An inflow of saline groundwater from a deep aquifer beneath the Albian Sands Muskeg River Mine pit required construction of dykes to contain the saline water and isolate it from the active mining area. Large volumes of mine waste earth fills were dumped and pushed into the saline water pond to raise the water level in order to reduce the hydraulic gradient and the inflow rate, and to ultimately provide a seal to prevent further water ingress or future reverse flow. The saline water was then pumped out of the pond to medium-term storage, to provide room for in-pit tailings storage. Detailed procedures were required to safely advance the fills into deep standing water. A geotechnical investigation program was performed to determine the properties and verify the integrity of the seal. Observations of the material behaviour during backfill placement into the pond, and the controlled slumping of the outer shell of the containment dyke that occurred during pond drawdown, provide insights into the behaviour of the lean oil sand fills.