Design of coarse tailings and dry ash disposal facilities

Abstract

The diamond industry has been disposing of its coarse tailings using conveyor and stacker systems for many years. The process plant typically generates two tailings products, a grit fraction (sand) and a coarse fraction (gravel), which are often combined on one dump. In some cases, the dump is stable with a single steep slope angle. However, in other situations a composite slope forms with settlement and intermittent slumping behaviour, this impacts on both design and operation. The thermal coal industry has also been disposing of dry ash for many years using either conveyor/stacking systems or haul trucks. Both systems work well, but the costs, deposition plans and stability aspects differ. Management of water and dust are also key factors. There are a number of key design and operational aspects that are similar between these diamond tailings and ash facilities, and would apply equally to filtered and dry stacked tailings. This paper aims to examine these similarities and show how these learnings could be built into new filtered tailings designs and operations to make them more efficient and stable.