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One of the challenges and opportunities in managing the deposition of surface deposited thickened tailings is
the potential for a change in the rheological properties after they exit the pipe during deposition. As tailings
flow away from the deposition point, for a slow enough flow, there may be sufficient time for water loss due
to “bleeding” and possibly capillary action by underlying desiccated tailings. This was studied using single
and multilayer tests in a flume, in which tailings were deposited at a variety of flow rates. Changes in the
rheological properties were evaluated by fitting the lubrication theory equations (Henriquez and Simms
2009; Liu and Mei, 1989) to equilibrium profiles. The rheological properties of the tailings were
characterised using slump tests and a vane rheometer. The geometry of the flows was visualised using high
speed cameras. The water flux out of the flowing tailings into underlying desiccated tailings was tracked
using tensiometers installed in the bottom layer. Preliminary results indicate that the yield stress can
substantially increase while the tailings are still flowing by both settling and capillary action into underlying
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