temperature and da oil ratio are interdependent temperature can vary from the pumpable temperature of the bitumen water slurry to the critical temperature of the decontaminating agent and preferably in the range of about 70 u00b0 c to about 200 u00b0 c which may depend on the decontaminating agent used as shown in fig1 the conditioned and demulsified slurry stream 7 enters the top section ps 1 of a first separation vessel v 1 and separates into an oil phase and an asphaltene water slurry phase the separation is quick more akin to oil water separation as in a desalting operation rather than the separation of two oil phases as in solvent extraction or deasphalting the bottom stream 9 exiting ps 1 is a water slurry of asphaltenes aggregates with some small amount of residual oil the settling slurry is a relatively thick slurry which can be difficult to pump or centrifuge therefore in a preferred embodiment the first separation vessel v 1 is divided into two vertically stacked sections with a downpipe linking the two sections the thick slurry 9 flows downwards through the downpipe to the lower portion of v 1 es which is otherwise sealed from the top section ps 1 and hence the de contaminated oil.