Settling,consolidation and desiccation behaviour of coal tailings slurry

Abstract

In this investigation, coal tailings have been subjected to the three consecutive processes of settling, consolidation and desiccation in a large purpose-built slurry consolidometer. The results of the tests were then compared with a self-weight-consolidated specimen desiccated in a column. The result indicates that the consolidation with a constant rate of loading removes about 56 mm water of the tailings specimen. With stronger capillary and higher unsaturated hydraulic conductivity after consolidation, the consolidated specimen delivered the majority (77% of available pore water) during evaporation stages II and III, when the soil surface is moist. More importantly, the sample is ready to deliver more water from underneath tailings to the surface for evaporation if the sample thickness increases. On the contrary, the self-weight consolidated specimen evaporated only about half of the available pore water during the moist-surface stages, and showed no capacity to deliver more water from the deeper tailings layers.