Accelerated consolidation of soft clays and mine tailings using a desktop centrifuge

Abstract

Many mine tailings streams contain appreciable quantities of clay minerals, examples including mineral sands fines, diamond and coal tailings. Tests to determine appropriate consolidation properties for these materials, as well as natural clays, are usually very time-consuming and the availability of equipment (such as a Rowe Cell) can sometimes be a limiting factor. This paper describes the development and testing of a modified desktop centrifuge that should eventually allow the determination of a full suite of consolidation material parameters within two days for soils of very low permeability and stiffness. The results of a series of consolidation tests using the desktop centrifuge are presented. The void ratio-effective stress profile is developed from these tests based on centrifuge theory and direct moisture content measurement. Development of a numerical model of the system to allow estimates of the permeability-effective stress profile of tested slurries is currently underway. Encouraging results have been obtained, indicating the ability of this method to provide reasonable results in the time frame outlined. Suggestions for further developments related to this procedure planned at The University of Western Australia (UWA) are outlined.

Centrifuge modelling of drawdown seepage in tailings storage facilities

“…Pore pressure transducers mounted in the base of the four centrifuge canisters indicate when consolidation has ceased. Material void ratio and corresponding effective stress are determined from sample slices taken from known depths and distances from the centrifuge centre of rotation (Reid et al 2012).…”