Few studies on the pump performance with authentic tailings slurries are available. Cooke presented results for various tailings products for solids concentrations by volume of up to 38% with yield stresses from 60 to nearly 100 Pa. He reported head and efficiency reductions of less than about 10% with a standard mining centrifugal slurry pump with a 0.365 m diameter impeller.
Sellgren et al. presented performance results for two tailings products for a pump with a standard closed shroud impeller or an open shroud type having an auger-like inducer. The head could not be maintained for flow rates less than about 50% of the BEP for the open and closed impeller at solids concentrations by volume, C, of 49 and 47%, respectively, for the fine tailings. The corresponding yield stresses were about 225 and 175 Pa as evaluated from pipeline loop data.
When operating a standard mining centrifugal slurry pump with water in excess of a point where cavitation begins, this is followed by rapidly increasing drops in both head and efficiency. It is indicated in the literature that cavitational behaviour may occur at lower flow rates with non-Newtonian slurries than for water. The observed difficulties in maintaining the head when handling highly thickened tailings slurries for moderately low flow rates together with possible cavitation tendencies for flow rates close to BEP influence the operation in practice.