Lime stabilization of soil-sludge mixtures for a potential use in oxygen barrier for mine site rehabilitation

ABSTRACT: Lime treatment of Acid Mine Drainage generates sludge that can be mixed with soils to produce soil-sludge mixtures (SSMs) that can be advantageously used as a component of a cover with capillary barrier effects. Generally, SSMs exhibit high water contents. This paper investigates the impact of lime addition on moisture content, post-compaction dry density and saturated hydraulic conductivity of sand-sludge mixtures (SaSM). In this study, sludge contents of 30% and lime dosages of 0 to 10% were used. The results indicate that the water content decreases as the lime dosage increases. The dry density after compaction increases but remains lower than the optimal density of the untreated SaSM. The saturated hydraulic conductivity of SaSMs containing 2 to 6% lime after 24 hours of cure decreases by 3 orders of magnitude compared to untreated SaSMs.