Consulting Solutions: Oil Sands Tailings Consolidation
The dewatering of oil sand tailings has become more imperative in the past few years with the creation of Directive 074. Tailings producers are now being required to have plans in place such that it is possible to demonstrate the achieving of five kPa of shear strength within oil-sand tailings deposits in reasonable times. Most existing oil--sand tailings are stored in large ponds which have been shown to be consolidating very slowly. The difficulty in the coming years is to develop strategies for the successful dewatering and closure of tailings storage facilities. The primary technical challenge to overcome is that the numerical modeling of the watering strategies is highly complex as it involves a combination of both large strain consolidation technologies and climate interaction.
SoilVision Systems has been investing significant amounts of research in the development of large strain software solutions and applying them for use in the oil-sand tailings area. The SVFlux™ and SVSolid™ products have been modified such that they can handle large strain consolidation behavior. Consulting solutions have been provided for oil companies in the following specific areas:
SoilVision Systems Ltd. has been involved in the large-scale multidimensional numerical modeling of the settlement behavior of tailings ponds. The benefit of these models is that the long-term ability of ponds to de-water through self-weight consolidation can be predicted.
A strategy which can be employed is to place either Mature Fine Tailings (MFT) or Thickened Tailings (TT) in smaller holding areas and allow self-weight consolidation and the effects of evaporation to dry the tailings. Tailings in rim ditch facilities are also exposed to freezing/thawing effects of the colder climate. SoilVision Systems Ltd. has been involved in numerical modeling of rim ditch facilities including the related aspects of coupling evaporation effects and accounting for the influence of freeze-thaw effects.
One of the strategies which might hold promise is the successive deposition of Oil-Sand tailings in thin lifts. Placement in thin lifts can maximize the influence of evaporation on the dewatering process. Subsequent placement of thin lifts on top of each other becomes challenging to represent in a numerical model. It is also challenging to couple the influences of both large-strain consolidation and Actual Evaporation (AE) from the surface of the tailings material. SoilVision Systems has been involved in being modeling of multi-stage thin-lift deposition while considering both the effects of large strain consolidation and climatic evaporation. SoilVision Systems Ltd. provides consulting services related to geotechnical numerical modeling of oil-sand behavior. If you are interested in discussing potential solutions please contact us here.
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