Modeling Desiccating Behavior of Mine Tailings

A one‐dimensional model of the sedimentation and desiccation of high‐clay‐content, subaerially deposited tailings is described. The approach is semi‐empirical and predicts average density and water content of a layer of tailings during sedimentation, first‐stage evaporation, and second‐stage evaporation, during which desiccation occurs. The method employs both geomechanical and soil physics principles and allows for varying evaporation, varying rainfall, and variation of initial height and solids content. Five tailings are analyzed, and model parameters are determined for each. Comparisons of recent experimental field data and the predictive model show good agreement. The laboratory equipment developed to provide parameters for analysis and methods used to obtain model parameters for other tailings are described. The model allows the effects of different initial layer depths, different initial water contents, and different available evaporation potentials to be compared with total drying time and resulting final dry density. Some examples of this are shown.