Numerical simulation of fine oil sand tailings drying in test cells

As a promising technology in disposal of mature fine tailings (MFT), atmospheric fines drying (AFD) is currently being implemented on a commercial scale at Shell Canada’s Muskeg River Mine near Fort McMurray, Alberta. AFD involves the use of a polymer flocculent to bind fine particles in MFT followed by thin lift sub-aerial drying. Upon deposition, the tailings-polymer mixtures are subjected to atmospheric conditions. The disposed layers undergo a cyclic drying and rewetting process due to precipitation and deposition of additional lifts on top of the dried layer. The current research aims to numerically simulate this process, including both periods of drying and wetting. An existing numerical drying model was extended with a realistic rewetting behavior, based on the shrinkage and water retention curves for drying as well as for rewetting. This improved model, that was validated with test results from laboratory columns, was used to simulate a large scale drying field test that is currently being performed by Shell Canada. The results of the simulation are published here without prior knowledge of the results by the authors, forming a Class A prediction.