REV09639

• Permit No: M1980244
• IBM Index Class Name: Revision
• Doc Name: 7.0 WATER BALANCE 7.1 WATER BALANCE MODEL
• Type & Sequence: AM8
• Media Type: D
• Archive: No

•
March 2000
-61-
993-2099.150
- 5.6 MG of operating volume which represents 20 feet of operating head
in the Phase II PSSA;
- 4.2 MG of solution draindown volume which represents 12 hours of
draindown based on a maximum anticipated solution application rate of
5,800 gpm;
- 16.0 MG of solution accumulation due to seasonal climatic variation at a
95 percent confidence level;
- 11.3 MG associated with the 100-year, 24-hour design storm event; and
- 12.8 MG of solution associated with the field capacity of the ore within
the Phase II PSSA.
The calculated volume of the Phase II PSSA solution exceeds the available storage by
approximately 7.5 MG. Therefore, the excess Phase II PSSA solution will be routed to the
20 MG capacity Phase I/II/III External Pond for storage.
• 7.3.3 Phase IV PSSA
The Phase IV PSSA was sized based oa the results of the probabilistic water balance. The
total Phase IV PSSA capacity was calculated to be 52.2 million gallons, which consists of
the following components:
- 3.7 MG of operating volume which represents an average 20 feet of
operational head in the Phase IV PSSA;
- 5.8 MG of solution draindown volume which represents 12 hours of
draindown based on the maximum anticipated solution application rate of
8,000 (gpm);
- 14.0 MG of solution accumulation due to seasonal climatic variation at a
95 percent confidence level;
- 14.6 MG associated with the 100-year, 24-hour design storm event; and
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I:\99\Z099\FINAL REPOR1~3099MAIN3.DOC Golder Associates