The Wizard Lake D-3A Pool has been undergoing a tertiary hydrocarbon miscible flood (HCMF) since 1983 after completing primary production(1951 - 1967) and a secondary HCMF (1969 - 1983), The operation is comprised of three solvent injectors, four push gas injectors, and 42 production wells. Fresh solvent injection (2,500 m(3)/day) was initiated in 1991 to make up for significant solvent coning and changed the flood design from a vertical flood controlled by longitudinal diffusion to a horizontal flood dominated by transverse diffusion. Recycling in this case also allows the old propane-plus bank to be replaced by a more economical ethane-plus blend. Under solvent recycling, the mixing zone would be stabilized (balanced injection and withdrawal) with its thickness increasing from zero at the injector to the maximum at the producer. The design problem is thus reduced to finding the solvent residence time at each producer and the corresponding minimum bank thickness needed to maintain miscibilily. The 1D diffusion equation coupled with miscibility data was used to calculate the required bank thickness and a full field 2D streamline model was used to predict the solvent residence times in this study. New solvent bank thickness design curves were generated by merging the residence times and the minimum miscible bank thickness data. Operating strategies based on the new design curves can potentially reduce the 1994 solvent bank size of 5.5 million reservoir cubic metres (rm(3)) to 3.0 million rm3. The concept applied in Wizard Lake can be extended to other miscible floods that involve solvent recycling.