2011-06-15_PERMIT FILE - M2010049

• Permit No: M2010049
• IBM Index Class Name: PERMIT FILE
• Doc Date: 6/15/2011
• Doc Name: Response- Review 5
• From: CGRS Environmental Services
• To: DRMS
• Email Name: MAC
• Media Type: D
• Archive: No

?June 6, 2011

Division of Reclamation, Mining and Safety (Division)
1313 Sherman Street, Room 215
Denver, Colorado 80203
/Attn: Mr. Michael Cunningham
RE: Varra Great Western Sugar Project
Response to Division Letter s/
DRMS File No. M-2010-0490-' Review 5
CGRS No. 1-135-12539aa
Dear Mr. Cunningham:
ENVIRONMENTAL SERVICES
RECEIV60
AJINN 15 2011
Dlv4sion of Reclamation,
Wining and Safety
I have been authorized by Varra Companies (Varra) to respond to your review comments of June
1, 2011.
Item 1 - The Division is requesting that the applicant establish a "Trigger Point" at which
mitigation or the evaluation of mitigation will occur. As written, the Division's proposed
criterion is not only impossible to comply with but also reflects its failure to recognize the basic
fundamentals of groundwater hydraulics and totally ignores the purpose and content of the
dewatering evaluation. The drawdown associated with such operations is not fixed in time or
space and trying to impose a single limit is not appropriate or achievable as the drawdown will
vary greatly across the site and exceed the Division's recommended criteria in close proximity to
the mine face. Natural groundwater levels cannot be practically maintained in close proximity
to mining operations. Obviously, Varra Companies does not have concerns regarding drawdown
beneath its property. We propose that sentinel wells be established as close as possible to its
property boundaries and the trigger point be used at these points. However, the Division should
acknowledge that during mining of the southern tracts, and possibly other areas, that water
levels will fall below the recommended trigger level. Both the Division and applicant should
recognize that mitigation may or may not be required even if the proposed trigger level is
exceeded or not. Varra also contends that its operations considers and maintains the hydrologic
balance as required by the Water Resources Division.
Item 2 -The wells that are appropriate for Trigger Point monitoring are monitoring wells 1, 2, 11
and proposed VCI wells 12 and 13. Well locations are presented on Exhibit C-1.
Item 3 - We concur with the three month criteria. As significant water level changes can take
months to occur we do not feel more frequent monitoring is warranted; however, we propose
that off-site wells in areas of concern may be added to the monitoring program if access can be
obtained. Areal extent, not frequency should be the issue of concern.
Item 4 - When the trigger point is met Varra will increase its assessment of surrounding land
use. It will obtain opinions from a qualified hydrogeologist as to possible impacts to surrounding
P.O. Box 1489 Fort Collins, CO 80522 T 800-288-2657 F 970-493-7986 www.cgrs.com