Rapid Measurement and Estimation of Saturated Hydraulic Conductivity of Mineral Slurries

Large strain consolidation (LSC) behaviour of mineral slurries regulates the performance of tailings management and reclamation plans. The hydraulic conductivity-void ratio relationship primarily influences this behaviour, dominating the long-term performance of fine-grained slurries with higher initial water contents. However, the determination of this function can be very challenging and time-consuming, considering the long duration of the conventional tests and significant variation in hydraulic conductivity values with the wide range of void ratios. This study focuses on identifying or creating a rapid method to evaluate the large strain consolidation parameters, especially the k-e relationship, of fine-grained soils by (i) establishing a relationship between the consolidation parameters and more easily measured properties and (ii) designing a self-weight consolidation setup to evaluate the k-e relationship using Instantaneous Profiling Method (IPM). For parts (i), a total of 79 k-e data sets of fine-grained soils are examined. When applying these new equations to the k-e data set, 94% of the predicted k values are within an order of magnitude of the measured data points. This is likely sufficient for this method to be used as a screening tool for tailings treatments. For part ii) The design of a prototype consolidometer is introduced and the consolidation behaviour of various fine-grained soils are evaluated. The prototype is designed as an alternative experimental setup to conventional laboratory tests and aims to rapidly assess the k-e equation for fine-grained soils. The test column was instrumented with tensiometers and capacitance-based sensors to determine pore water pressure and volumetric water content, respectively. Also, a robotic arm is connected to the sensor probe for more detailed profiling. The collected data is then utilized to determine the hydraulic conductivity of the tested fine-grained soils and polymer-amended fluid fine tailings using the IPM method. The compressibility curves of the tested materials also determined using the measured data from the prototype consolidometer. The measured data and the predicted behaviour of the material are compared using a large strain consolidation software. The results demonstrated that, the method can successfully determine the k-e relationships in a shorter period of time compared to conventional laboratory tests.