Authors: J. Zhang, S. Daughney, T. Plikas, L. Gunnewiek, T. Miller - Xstrata, A. Lagace - Xstrata, D. Yaschyshyn - Xstrata
8th International Conference on Acid Rock Drainage, June 25, 2009
Abstract
Settling ponds are used extensively for the treatment of neutral and acidic mine drainage as they are a relatively adaptable and low cost solution. However, the efficiency of settling ponds for the removal of suspended solids and precipitated metals may be compromised if the pond is not properly designed. The significance of this work is that a comprehensive three-dimensional computational fluid dynamic (CFD) model has been developed as a tool to investigate the major processes influencing pond performance: pond hydraulics, particle settling, and sludge resuspension. Model output has been validated using data from the Tailings Management Area (TMA) at Xstrata Copper’s Kidd Metallurgical Site (Metsite) in Timmins, Ontario, Canada. Differences between the model predictions and field measurements that correlate with the total suspended solids (TSS) concentration were found to be less than 5% at conditions of high pond inflow. This work has found that small particles present in the pond inflow exert a dominant influence on the effluent TSS concentration, and coagulant addition was shown to be an effective means of controlling the outlet TSS concentration. The model has also been successfully utilized to assess proposed changes to the pond configuration; for example, addition of baffles was demonstrated to increase short-circuiting and inhibit particle settling. In the future, the model is to be employed to define a TMA management strategy that minimizes environmental risk and operating costs.
