Abstract
As part of a project to study the feasibility of reducing discharges from a potash mine by stowing tailings materials underground, a series of beaker tests was carried out to examine the efficiency of a number of binders applied to different ratios of centrifuge and filter cakes. It was envisaged that the tailings could be treated with a binder to produce a solid material within 24 h of placement underground. In total, 73 combinations were produced and compared. Strength development tests were performed on two mixes with three binder combinations over a period of 14 days in the SChEME laboratories at the University of Nottingham, England. Viscosity measurement tests and subsequent rheology modification tests were also carried out to establish the pumping characteristics of various mixes.
Stowage of the 100% filter cake slurry was accorded precedence on environmental grounds, but its pseudo-plastic nature was found to present serious pumping difficulties. It was concluded that neither the use of binders to stabilize the placed slurry nor that of chemical admixtures to modify the slurry viscosity would be feasible economically. As a consequence, it is now proposed to use coarse salt flotation tailings in the centrifuge cake to alter the slurry viscosity and to add binders to part of the slurry only, employing this material for the construction of underground retaining weirs.
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