Large volumes of tailings are produced annually by the gold
mining industry of Western Australia. This material is
hydraulically discharged into large storage facilities using
sub-aerial deposition methods. Much of the gold comes from
highly weathered rock, resulting in tailings with significant clay
contents. Consolidation of these materials can be very slow,
particularly if occurring under the effects of self-weight alone.
To optimise the consolidation behaviour of the tailings, disposal
strategies can take advantage of the effects of evaporation by
allowing each tailings layer to dry before the next layer is
deposited. In the last 20 years, much of the gold processing in
Western Australia has utilised saline groundwater. As the saline
tailings dry, the surface will develop a thin salt crust. Laboratory
tests have shown that these crusts can drastically reduce the
surface evaporation, adversely affecting the behaviour of the
storage. This problem has been the focus of an extensive research
programme, with the objective of obtaining a fuller
understanding of the mechanisms controlling the coupled
consolidation and evaporation behaviour of saline gold tailings.
Part of this study involved site investigations of a wide range of
storages to ascertain their current states. Methods of gaining
access to the tailings following deposition were developed.
In situ testing and high quality sampling were conducted on each storage and samples returned to the laboratory for analysis. These investigations have enabled full characterisation of the storages to be accomplished. Examples of data are shown herein and the implications of the results are discussed.