Mine and industrial dams - Geotechnical Engineering of Dams - page 793

Combined upstream and downstream construction (Lyell and Prakke, 1988 , reproduced
with permission of ASCE ).

Figure 19.21.

Figure 19.22. Construction of tailings embankment using the centreline method.

to form a relatively sandy beach adjacent to the downstream zones to control piezo-
metric pressures.

If rockfill rather than tailings underflow is used for the downstream zones in Figure
19.20 , a graded filter zone will be required between the tailings and the rockfill to prevent
erosion of the tailings into the rockfill which could lead to piping failure.
A combination of upstream and downstream methods may be used. An example is
shown in Figure 19.21.

19.5.2.3 Centreline method
Figures 19.22 and 19.23 show two versions of construction by the centreline method.
The important features of this approach are:

- The embankment is partly constructed of selected material. In Figure 19.22 a zoned
water storage type section has been used for the downstream part of the embankment,
with the upstream part constructed on spigotted tailings. In Figure 19.23 cycloned tail-
ings have been used, with the cyclone underflow discharged on the downstream side
and the overflow finer portion on the upstream side;