Abstract:
Undisturbed sampling of gold tailings, especially under
the water table, is difficult and in many cases impossible.
For this reason laboratory testing of tailings is generally
conducted on reconstituted material. It has been shown
that laboratory sample preparation methods can affect
the mechanical behaviour of cohesionless soil and it is
generally believed that the difference in mechanical behaviour
is attributable to a difference in the fabric
(particle arrangement) inherent in the preparation method.
An experimental programme was conducted to (a)
examine the fabric which ensues upon sample preparation
and (b) to investigate the effect of any fabric differences
on the mechanical behaviour of gold tailings.
Comparison was made between the behaviour and fabric
of undisturbed and reconstituted moist tamped and slurry
deposited samples. The results from the experimental
programme show that there is indeed a difference in
fabric between undisturbed and reconstituted gold tailings
samples. Slurry preparation generally replicates the
fabric and behaviour of the undisturbed sample better
than moist tamping, but neither fully replicates the
undisturbed sample. At large strains, the samples reach a
unique critical state friction angle, but at different stress
states.