12 February 2020
20137096-009 Rev A
Loading condition
Minimum FoS
Description
excess pore water pressures, are adequately characterised with effective stress drained shear strength parameters.
This higher FoS is suggested if the critical failure surface and failure event could result in loss/release of tailings or mine effected water.
Undrained (or partially drained) - no potential loss of containment
Applicable in cases described above for the undrained condition except that this lower FoS is suggested if the critical failure surface and failure event would not result in loss/release of tailings or mine effected water.
1.3
Cyclically reduced undrained/drained shear strength and/or liquefied residual shear strength for potentially liquefiable materials. The range of FoS is related to the level of confidence in selection of residual shear strength and a FoS of 1.0 may be adequate for use with lower bound results.
Post-seismic
1.0 – 1.2
4.0 STORAGE CAPACITY The storage capacity of the TSF is presented in Table 1 and shown in Figure 2. This graph shows a series of dots, which are equivalent to the embankment construction stages, built progressively through the life of the TSF, beginning with a Starter Dam and then followed by 5 construction stages. The final height of the embankment will be sufficient to store the tailings that are eventually re-treated, up to a maximum capacity of just over 20 Mm³.
Table 3: Tailings storage volume sin the TSF.
TAILINGS HEAD RL (m)
TAILINGS (m³)
CUMULATIVE TAILINGS (m³)
289
2,795,840
2,795,840
299
2,241,363
5,037,203
309
2,886,612
7,923,815
319
3,608,601
11,532,416
329
4,531,352
16,063,768
334
2,706,244
18,770,012
10
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