Fine tailings from the Oil Sand Mining and Extraction Plant of Syncrude Canada,Ltd. were repeatedly extracted with distilled water and allowed to react for 24hours at each stage. The concentrations of major extractable ions were measuredand used in the geochemical computer program SOLMINEQ_88PC/Shell. Calcite wascalculated to be stable up the second extraction stage. Gypsum is not stable inthe initial liquid at either 25 or 60 ° C. Dissolved SiO2 is inequilibrium with quartz in the starting suspension, when the calculation isdone for 60 ° C. Sio2 remains high in subsequent extracts. Illitedissolution is insufficient to explain the K and Sio2 concentrationsin the extracts. A hypothetical phase such as analcime is also insufficient toexplain Na and Sio2 concentrations. The results suggest furtherinvestigation of amorphous and microcrystalline phases should be carried out.High HC03 - and SO42- concentrations cannot beexplained by mineral reactions, and may be associated with the oxidation oforganics associated with the solids during the extraction procedure. Volumereduction of fine tailings by recrystallization of colloids should be tested asa part of a study to characterize the kinetic response of the tailings tochanges in the chemical environment.