Oil sand tailings are disposed of in large tailings ponds by upstream dyke construction and beaching. Sand separates and forms a gentle beach; the thin sludge flows into the pond as a density current, sedimentation takes place, and the rate of density increase rapidly becomes dominated by consolidation processes. The effect of the presence of bitumen on particles is an acceleration of sedimentation as the result of plastic collisions and agglomeration of particles. However, consolidation time is lengthened because the sludge solids have low relative densities and permeabilities.New system definitions are presented to account for the presence of bitumen as a non-mobile phase. A nomogram for oil sand sludge is presented to allow direct determination of sludge density and solids content from bitumen and water content. New experimental procedures for index tests are given, as the presence of bitumen creates laboratory difficulties. Grain size analysis and clay mineralogy require removal of bitumen, but Atterberg Limit data must be generated from intact sludge.