Prediction of fine tailings settlement in pit lakes using a population growth model

Abstract

A model for predicting the settlement trajectory in saturated fluid fine tailings deposits is described. The model uses a population growth function and leverages established theories in soil mechanics, clay–water surface interactions and biogeochemistry to derive compressibility and permeability functions for predicting the settlement behaviour of fine tailings in deep deposits, typical of end pit lakes. The method is particularly useful for tailings treated with flocculants and/or coagulants with continuously changing compressibility and permeability parameters during deposition. For oil sands or mineral sands fluid tailings treated with or without high doses of a coagulant and/or a flocculant, the consolidation parameters determined from the model are comparable with those measured using standardised large-strain consolidation methods, and the predicted settlement using a modified Gibson’s finite-strain equation closely describes the measured settlement and void ratio profiles in geocolumns.