PERMFILE100181

• Permit No: M1999098
• IBM Index Class Name: Permit File
• Doc Date: 12/6/1999
• Doc Name: RIVERVIEW RESOURCES 112 APPLICATION CAMAS COLO INC FN M-99-088 HYDROLOGIC REVIEW COMMENTS
• From: DMG
• To: CHRISTINA KAMNIKAR
• Media Type: D
• Archive: No

• • iii iiiiiiiiniii iii
STATE OF COL~~v 9~v~
DIVISION OF MINERALS AND GEOLOGY
Depanmenr of Natural Resources
I ;I }Sherman SL. Room '_ I S
Denver, Colorado 80?03
Phone: [phone]-}i67
FAX: 1}03183?-8106
Date : December 6, 1999
DI `/151 ON OF
MINERALS
GEOLOGY
R E C L A M A T I O N
MIN ING•SAFETY
To : Christina Kamnikar Bal o«ens
A envernnr
Greg E. `.Valcher
From :Tom Schreiner /,`/ Esecume Direao~
Michael B Lonb
Dwmun Ducaor
RE : Riverview Resources 1 12 Application, CAMAS Colorado, Inc. ,File No. M-99-088
Hydrologic Review Comments
The following hydrologic concems were identified during a review of the above mentioned
permit application and corresponding public comments. These concerns will need to be resolved
to the Division's satifaction prior to a recommendation of approval.
Exhibit D - Minine Plan
1. Several objectors have raised concerns regazding possible flooding and corresponding impacts
during mining and reclamation. Review of the mine and reclamation plan indicates that a
significant portion of the affected land may be subject to periodic flooding throughout the life of
the operation. Prior to a recommendation of approval the Division will require the applicant to
provide a thorough floodplain-impact analysis for the affected land and surrounding area. The
analysis should be developed using the most recent and accurate floodplain information
available. (The Division understands that a 1999 floodplain study for the area in question is
being finalized and has been prepared through the cooperative efforts of Weld County, City of
Greeley, U.S. Army Corps of Engineers, and the Colorado Water Conservation Board). At a
minimum, the Division will require the applicant to provide a map that clearly defines the
boundaries of the 100-year floodplain for the Cache le Poudre River relative to the proposed
affected area, and an engineering analysis that can adequately predict any changes to the current
100-year floodplain elevation, width boundaries of the current 100-year floodplain, and flowpath
of a 100-year flood event both during mining and during final reclamation based on the proposed
plans.
2. Other related floodplain concems that will need to be addressed include the following:
a. All product, overburden; and topsoil stockpiles should be located outside of the boundaries of
the 100-year floodway, if possible. The applicant should provide a map showing the location,
orientation, and configuration of any stockpiles.