Filtered tailings versus thickened slurry: four case studies

Abstract

Shortage of water (or a high cost of water) drives miners to look towards more costly water extraction technology for their tailings. Filtration technology offers greater water recovery than the more commonly used thickening technology, but this comes at a greater cost, both in terms of capital outlay as well as its operation. The transport of the filtered tailings exacerbates this problem, particularly where long distances come into play. The storage of the filtered tailings can sometimes be achieved at less cost than that of thickened tailings slurry, depending on the topography of the surrounding area. The economic feasibility of filtration technology over slurry thickening technology ultimately comes down to the cost of the make-up water that is required. This paper presents four different copper mining operations in which these two technologies have been considered for the treatment of tailings. In each case study the tailings dewatering, transport, storage and closure has been designed and costed, both in terms of capital and operating expenses. The overall findings of each study are presented and discussed. Finally, the break-even point for filtration at each mine has been estimated, in terms of the water cost.