2008-09-17_REVISION - M1980244 ‎(28)‎

• Permit No: M1980244
• IBM Index Class Name: REVISION
• Doc Date: 9/17/2008
• Doc Name: Response to Adequacy Review
• From: CC&V
• To: DRMS
• Type & Sequence: AM9
• Media Type: D
• Archive: No

water to the Grassy Valley Creek to maintain flow rates similar to those currently observed
• throughout the year due to the expected impact of mining in the Wild Horse East Cresson
Mine Expansion area, which will lower the water shed feeding the creek & wetlands. The
expected decrease based on the mass balance will ran ge anywhere from 20 % to 30% of the
total flow. Where would this supplemental water come from? Where is the warranty for the
purchase of this water in Exhibit "L"? Worst case scenario, the Division would like to see
analyzed would be that the proposed mining activities could cut of the flow in Grassy
Valley to between 10-15 gpm. Granted the lower portion of the water shed will not be
impacted and as such one can't assume 0 flow. How would CC&V mitigate if the worst case
scenario takes place? What will happen to the entire Alluvial Valley Floor if the worst case
happens? Please discuss that possibility in detail and how CC&V will address the possible
impacts if it takes place.
Response.
Section VI.E. contains nine separate questions if CC&V assessed this correctly. CC&V
provides the following response to these multiple matters. As for the riparian areas, CC&V
proposes to monitor these areas during operations within the catchment area of Grassy
Valley.
Ground Water
Ground water levels would be continuously monitored at a total of 14 locations as shown in
Table 2. The well locations are shown on Figure 4 included as Attachment 8. Wells would be
• fitted with transducers from which data would be downloaded on a quarterly basis.
Ground water quality would be monitored by sampling all the monitoring wells in Table 2
quarterly, and analyzing water samples for the standard suite of parameters for CC&V's
current ground water monitoring program.
Table 2 - Ground Water Monitoring of Rinarian Area
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GVMW-04A 43464 62788 10028 480 90 480 Xgd Center Grassy (rock)
GVMW-04B 43470 62793 10028 50 28 50 Xbs Center Grassy (alluvium)
GVMW-08A 47418 59488 9884 250 200 250 Tph Downgradient (rock)
GVMW-08B 47437 59483 9883 50 20 50 Tph Downgradient (alluvium)
GVMW-10 45984 60589 9960 270 206 270 Tph ECOSA monitor (rock)
GVMW-14B 41874 63257 10089 100 77 98 Xgd North Cresson (shallow)
GVMW-14C 41899 63237 10089 625 484 612 Xms North Cresson (rock)
GVMW-16B 42158 63492 10177 102 68 102 Xbg Twin for PZ-3 (rock)
GVMW-23A 50041 59292 9764 250 40 100 Xgd Diatreme boundary (rock)
GVMW-23B 50032 59310 9770 40 10 40 Xgd Diatreme boundary (alluv)
PZ-1 42560 62981 10092 38 8 38 Qal Riparian area (alluvium)
PZ-2 42374 63163 10092 31 9 29 Qal Riparian area (alluvium)
PZ-3 42098 63435 10105 20 10 20 Qal Riparian area (alluvium)
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