Freeze fracture preparation and subsequent direct observation of frozen hydrated samples in an electron microscope has been used to characterize the morphology and composition of oil sands sludges. A card house type of structure has long been suggested to explain the long term stability of sludge to consolidation but the relative role of organic/mineral or mineral/mineral interactions in determining the stability of the structure is not well understood.

Electron microscopic techniques are discussed which might allow direct determination of the relationship between the various sludge components_ Evidence is presented which suggests that it is possible to directly observe the sludge structure.