APPCOR12220

• Permit No: C2006085
• IBM Index Class Name: Application Correspondence
• Doc Date: 10/2/2007
• Doc Name: Adequacy Review Responses Memo
• From: Mike Boulay
• To: Kent Gorham
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMA710N, MINING AND SAFETY
Department of Natural Resources
1313 Sherman 5[., Room 275
Denver, Colorado 80203
Phone: [phone]
FAX: [phone]
COLORADO
DIVISION OF
RECLAMATION
M[NING
- &-
SAFETY
INTEROFFICE MEMORANDUM
Bill Owens
Governor
TO: lent GOTham Russell George
Executive Director
/
/~ Ronald W. Cottony
FROM: r
Mike Boulay M Division Director
Natural Resource Trustee
DATE: October 2, 2007
SUBJECT: Northfield Mine, Permit No. C-2006-085
Permit Application Adequacy Review Responses
I have reviewed the adequacy responses prepared by Environmental Alternatives, Inc., and
Weaver Engineering Services for the Northfield Mine that were received by the Division on
August 23, 2007. My original adequacy questions were provided to you in a June 15, 2007
memo. These were incorporated into our June 18, 2007 adequacy letter as items 12a, 13a, 13b,
15a, 17a, 17b, 34, and 34a. I have the following remaining comments.
12a. Derivation of the hydraulic conductivity values was provided in Northfields response, but
was not incorporated into the permit application package (PAP) as requested. Please
incorporate the discussion and analysis of pump test data into the PAP for future
reference.
13a. Northfield provided well information and a discussion of the Chandler Creek alluvium in
the response letter but did not update the permit application package (PAP) as requested.
Please update Section 2.04.7 with the Chandler Creek alluvial deposit description and
available information.
13b. Northfield proposes to construct one monitoring well in the Chandler Creek alluvium at a
down gradient location for monitoring and compliance purposes. Please provide the
Division with the monitoring well design and location for review and approval prior to
installation.
In response to 13b, Northfield does not propose an up gradient well in the alluvium
because it is their opinion that the alluvium is not regionally saturated up gradient of the
permit boundary. This discussion should be included in the Hydrology Description,
substantiated with available information and incorporated into the PAP (see item 13a.
above).
15a. Response accepted.
Office of Office of
Mined Land Reclamation Active and Inactive Mines