Description
Criteria
Units
Basis Value
Source
Tailings beach
-
%
0.5
Heritage Minerals
slope
Tailings storage
-
Mt
Maximum feasible
Heritage Minerals
requirement
storage
Water Management
Minimum
-
m
1
WSP
freeboard
Wet season water
1:100 AEP 3 month wet
mm
1,260
WSP – Wattle Gully
storage allowance
seasons rainfall depth
Dam Break Report
Design flood
120 hr probable maximum
mm
2,620
WSP – Wattle Gully
event
precipitation
Dam Break Report
Extreme storm
1:1,000 AEP 72 hr storm
mm
1,020
WSP – Wattle Gully
storage
Dam Break Report
Minimum decant
-
m
No allowance
-
pond depth
4.3.2. Dam Break and Consequence Category Assessment
A dam break assessment (DBA) and consequence category assessment (CCA) for the proposed Upper
Mundic Gully TSF has been undertaken with results summarised in Table 18. A copy of the full report
(Revision C) is provided in Appendix C.
Table 18. Summary of results for consequence category assessment
Guideline
Consequence Category
Stage 1
Stage 2
ANCOLD – Dam Break
Significant
High B
ANCOLD – Environmental Spill
Low
Low
DETSI – Dam Break
Low
Significant
DETSI – Failure to Contain (Overtopping)
Low
Low
DETSI – Failure to Contain (Seepage)
Low
Low
The consequence classification of Upper Mundic Gully TSF is ‘Significant’ and ‘High B’ based on the
ANCOLD criteria and ‘Low’ and ‘Significant’ based on the DETSI criteria for Stage 1 and Stage 2
respectively. The overtopping/ environmental spill and seepage consequence categories were
considered to be “low’ for both ANCOLD and DETSI.
82
Wulguru Technical Services Pty Ltd – Supporting Information to Amend an Environmental Authority
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