Effect of initial specimen height and solids concentration on the consolidation parameters of fine-grained coal tailings

Abstract

Proper understanding and analysis of the consolidation behaviour and parameters of tailings from a slurry-like to a soil-like state are vital for the design, management, and assessment of a tailings storage facility (TSF). Fine-grained coal tailings slurry can undergo relatively rapid and substantial settlement from a slurried state and can experience relatively slow and limited self-weight consolidation, remaining slurry-like and under-consolidated, rather than soil-like. A large purpose-built slurry consolidometer having a newly developed consolidometer cell, instrumented with load cells and pore water pressure transducers, is well-suited to test tailings from a slurry-like to a soil-like state and enables the constant rate of loading (CRL) to simulate the build-up of tailings. CRL is more representative of the rate of rise of tailings in a TSF than incremental step loading. By conducting consolidation tests on fine-grained coal tailings from a slurry-state under a loading rate of 0.12 kPa/min up to applied stress of 320 kPa, this research investigated the effect of initial specimen height (ISH) and initial solids concentration (ISC) on consolidation parameters and hydraulic conductivity. Using ISH and ISC as independent inputs, a statistical model has been proposed to estimate the consolidation settlement at the end of the slurry consolidation test.