Abstract: An improvement in the treatment of sludge recovered from a pond containing tailings from a water extraction process of tar sands characterized in that the froth produced from a treatment of the sludge is diluted with water which is at an ambient temperature, and the diluted froth is agitated and aerated vigorously for a short time to obtain an upper froth layer which contains most of the bitumen and substantially reduced amounts of mineral and water. The upper froth layer is obtained by, e.g., skimming it from the froth produced by the agitation and aeration.