2007-12-19_APPLICATION CORRESPONDENCE - C2006085

• Permit No: C2006085
• IBM Index Class Name: APPLICATION CORRESPONDENCE
• Doc Date: 12/19/2007
• Doc Name: Review Memo on Findings Document
• From: Mike Boulay
• To: Kent Gorham
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 2t5
Denver, Colorado 802D3 ~ C O L O R A D O

Phone: [phone] DIVISION O F
RECLAMATION
FAX: {303) 832-8106 MINING
INTEROFFICE MEMORANDUM SAE Y
Bill Owens
TO: Kent Gorham cover"or
Russell George

FROM: Mike Boulay /~ Executive Director
Ronald W. Cattany
Division Director
DATE: December 19, 2007 Natural Resource Trustee
SUBJECT: Northfield Mine Findings Document, Permit No. C-2006-085
As requested I have reviewed the Proposed Decision and Findings of Compliance document for
the Northfield Mine specifically with regard to groundwater hydrology. I just have a few
comments with regard to the stipulations. The remainder of my comments are editorial only.
In Stipulation No.l, we are requesting an initial water sample from the alluvial point of
compliance well prior to facility construction. To be consistent with our baseline data collection
Rules [2.04.7(1) (a)] which require seasonal quantity and quality, shouldn't we have them collect
and analyze more than one initial sample for the purpose of establishing baseline conditions?
Particularly since this is an alluvial aquifer which may fluctuate with seasonal changes, I
recommend that they collect and analyze two baseline samples from spring and fall. As a
suggestion the stipulation could be revised to read "...AND SEASONAL WATER QUANTITY
MEASUREMENTS AND WATER QUALITY SAMPLES HAVE BEEN TAKEN AND
ANALYZED FOR..."
Likewise in Stipulation No.2, consider revising the stipulation to read "...AND BASELINE
WATER LEVELS AND WATER SAMPLES HAVE BEEN TAKEN FOR ANALYSIS: '
In the discussion at the bottom of page 181eading up to Stipulation No. 3 regarding consumption
of water I have the following comments: 1) it would be helpful to explain where the water will be
produced from for the consumptive uses described. Will most of the water be obtained from
mine inflows for use in the mine and will there be a production well for the domestic uses?
2) Regarding Northfields claim that groundwater is nontributary, has the operator considered
both alluvial water and bedrock water that may be tributary and potentially impacted. In
Stipulation No. 3 it may be helpful to add the following: "PRIOR TO THE CONSUMPTIVE
USE OF EITHER ALLUVIAL OR BEDROCK GROUND WATER WITHIN THE PERMIT
BOUNDARY..."
On page 20 Item D, the findings states "an alternative subdrainage system for the area has been
proposed." It would be helpful to provide a brief explanation of what the sub drainage system is
and in what section of the permit application it is described.
Office of Office of
Mined Land Reclamation Active and Inactive Mines