The present invention is a system and method for handling oil sands tailings and in particularly thickened oil sands tailings. The invention includes adding gas stream, possibly acid gas, to thickened tailings. Mixing the tailings and the gas to disperse the gas into the tailings and pumping the tailings for disposal or further treatment. The gas reduces the tailing viscosity by physical and chemical means and can dissolve and react with thickening chemicals within the tailings. The lower viscosity mixture of the thickened tailings and the gas is pumped through a pipe for further treatment or disposal. The mixture also provide scrubbing effect on contaminates within the gas, if contaminate gas is used.