Effect of seasonal weather variations on the desiccation behavior of treated oil sand fine tailings

Abstract

The main objective of this investigation was to understand the desiccation behavior of treated oil sand fine tailings. A numerical model was developed to understand the interaction of material properties with the climatic parameters. The material properties included a depositional solids content of 60 %, an air entry value of 1000 kPa and a residual suction of 3,0000 kPa, a J-shaped shrinkage curve, a saturated hydraulic conductivity of 3 × 10⁻¹⁰ m/s, and a vapor conductivity of 5 × 10⁻¹³ m/s. Likewise, the climate data indicated the presence of three distinct seasons (winter, spring, and summer). Under the mean climate conditions, desiccation at the surface is negligible till the end of March (99 % saturation) but picks up during the remainder of the year to 70 % in May, 76 % in September, and 88 % in December. Furthermore, de-saturation occurs up to about 4 m beyond which the deposit is not affected by atmospheric parameters. The corresponding values of soil properties at the surface by the end of May and the end of September are as follows: soil suction 2500 and 1900 kPa, solids content 72 and 71 %, and settling potential 25 and 20 %.