Effect of Stepwise Increase in Tailings Deposition on Tailings Dam Stability

Tailings from metalliferous ore processing are stored in tailing-storage facilities. Fresh tailings contain high content of water, and this may contribute to the instability of the facilities. One way of depositing tailings into the facilities is to lay a layer of fresh tailings on top of previously deposited tailings and let the newly deposited tailings settle down for some time before another layer is laid. This paper utilises GeoStudio’s software packages SEEP/W, SLOPE/W, and SIGMA/W to analyse the effects of such deposition processing on the stability of a tailing dam. It is found that, generally, as more layers are added, the factor of safety of the upstream slope surface of the dam embarkment increases, while the factor of the safety of the downstream slope surface is not affected. The thickness of the layers does not affect the factor of safety of the downstream slope surface. The factor of safety of the upstream slope surface is affected by the thickness of the layers: the thicker the layers, the higher the factor of safety. Hydraulic conductivity is one of the factors that influence the settlement times of the deposited tailing layers.