2016-09-26_REVISION - M1980244

• Permit No: M1980244
• IBM Index Class Name: REVISION
• Doc Date: 9/26/2016
• Doc Name: Adequacy Review Response
• From: CC+V
• To: DRMS
• Type & Sequence: AM11
• Email Name: TC1
• Media Type: D
• Archive: No

47. Appendix 7, Figures 4 and 5
• These two figures show a constant Squaw Valley [sic] PSSA pond volume over 225
months. This is counterintuitive unless the assumption is to turn off the pumps once the
PSSA water level falls to a given level, which is not what the Division staff has
observed in the field for the Arequa Gulch VLF operation. Please clarify the assumption
and provide the Division assurance the proposed operational plans for the Squaw Gulch
PSSA are reflected in the water balance.
RESPONSE:ERC utilized the maximum pumping rates that were provided in the design
criteria, and whenever possible, allowed the model to pump the PSSAs down as much as
the pumping rates would allow, until the minimum operating volume was reached. The
constant pond volumes shown in these figures are due to the monthly time step used by
the model. Because the pumping rates were greater than the total inflow rates reaching
the PSSAs each month, this resulted in the PSSAs being pumped down to their minimum
level in each of the months of the simulation. If the model had been constructed using a
daily time step, more fluctuation in the pond volumes and depths would be depicted on a
day to day or week to week basis, however over the course of each month, no water is
expected to accumulate in the PSSAs beyond the minimum operating volumes. In order
to ensure that a large single day storm didn't create a problem in terms of the water
balance, a 100 year storm plus draindown from a power outage were also considered.
This evaluation showed that even for extreme fluctuations caused by an anomalous
single day event, the facilities have sufficient capacity(see response number 44).
48. Appendix 7, Figures 11, 12, 15, 16, 19, 20, 23, 24, and 27
• These figures show a constant PSSA pond volume over the entire simulation period.
This is counterintuitive unless the assumption is to turn off the pumps once the PSSA
water level falls to a given level,which is not what the Division staff has observed in
the field for the Arequa Gulch VLF operation. Please clarify the assumption and
provide the Division assurance the proposed operational plans for the Arequa Gulch
PSSA's are reflected in the water balance.
RESPONSE: The reason for these results is the same as the reason for results
discussed in response 47. Over the course of a month the pumping capacity for each
facility exceeds the total anticipated inflows. The evaluation of the 100 year storm and
draindown in addition to normal operating volume illustrates that sufficient capacity
exists in the facilities.
49. Appendix 7, Table B.1
• The water balance is dated November 2015. The Division received an update to the
Squaw Gulch PSSA elevation-storage capacity based on survey data in January 2016.
Does Table B.1 reflect the as-constructed survey or does it need to be updated?
RESPONSE: The revised Squaw Gulch PSSA filling curve has been provided to ERC,
and the water balance report has been updated to reflect the new results. The updated
filling curve, which is based on the survey data is provided in Table B.1 of Attachment
IL
VOLUME IV—APPENDICIES 9 THROUGH 14
50. Appendix 9, Water Purchase Agreements.
• These agreements are signed by AngloGold Ashanti (Colorado) Corp. representatives
for Cripple Creek and Victor Gold Mining Company, and not Newmont representatives.
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