2008-12-12_REVISION - C1982056

• Permit No: C1982056
• IBM Index Class Name: REVISION
• Doc Date: 12/12/2008
• Doc Name: Adequacy Review Memo
• From: Kent Gorham
• To: Janet Binns
• Type & Sequence: MR233
• Email Name: KAG
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
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Denver, Colorado 80203 I
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Phone: [phone] RECLAMATION
FAX: [phone] MINING

SAFETY
Bill Ritter, Jr.
Governor
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t Harris D. Sherman
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Ronald W. Cattany
To: Janet Binns Division Director
Natural Resource Trustee
From: Kent Gorh
CC: Dan Hernan
Subject: MR-233 Adequacy Review, Foidel Creek Mine, C-82-056
Date: December 12, 2008
I have completed my review of the revised materials for the clay storage area (MR-233) at the
Foidel Creek Refuse Disposal Area. My comments are as follows.
I concur with you and Dan that the area is too large to consider the area as a Small Area
Exemption (SAE). Furthermore, we have an unofficial directive to not include any fuel storage
within areas designated as an SAE. Therefore, the disturbance does not qualify as an SAE
candidate due to both size and the inclusion of fuel storage within the disturbance area.
I also concur with the applicants assessment that Pond D has adequate capacity to contain and
treat the runoff from a 10-year event, including the proposed disturbance, due to the fact that
much of the area in the current Pond D design either does not report to the pond or is in a better
hydrologic condition than assumed in the pond design model. The addition of about 5 acres of
disturbance should not compromise Pond D in any way at this time.
Any culverts added should be equal in size to the size of the next culvert downstream in ditch
RDA-l. Map 24 shows an 18 inch culvert in section RDA-lc.
And finally, I recommend that the hydrology and sedimentology modeling be brought up-to-date
when the applicant proposes expansion of the RDA to the west, currently scheduled for 2009. At
that time, current disturbances and any new proposed disturbances can be accurately modeled
within the Pond D watershed. As always, self-monitoring of the Pond D effluent under the
approved WQCD discharge permit should be reviewed to identify any unexpected problems or
issues.
Considering my comments above, I have no concerns and the revision can be approved as
submitted. Let me know if you have any questions.
Office of Office of
Mined Land Reclamation Denver • Grand Junction • Durango Active and Inactive Mines