Environmental Engineering Reference
In-Depth Information
Figure 19.19.
Tailings embankment construction using the downstream method and zoned earth and
rockfill construction.
Figure 19.20.
Tailings embankment construction using the downstream method and cycloned tailings
(ICOLD, 1982d).
The important features of this approach are:
- The embankment is constructed of selected material. In the case of Figure 19.19, a water
storage dam type cross section has been used, with an upstream impervious zone and
internal drainage control. This allows water to be stored adjacent to the embankment. In
Figure 19.20 the embankment is constructed from the coarse underflow part of cycloned
tailings. These may be compacted as described in Section 19.3.2. Avoidance of internal
erosion and piping is dependent on the water pond being kept well away from the embank-
ment to control the position of the phreatic surface;
- The embankment is best constructed, at least partly, of permeable material to allow
control of piezometric pressures;
- It is desirable, but not necessary, to place the tailings in a controlled manner. For
Figure 19.19 type construction no control is necessary (from a stability viewpoint). For
Figure 19.20 type construction it would be important to spigot or cyclone the tailings
