GENERAL50567

• Permit No: C1981037
• IBM Index Class Name: General Documents
• Doc Date: 12/10/1992
• Doc Name: CITIZENS REQUEST FOR INSPECTION DATED NOVEMBER 13 1992 GEC C-81-037
• From: DMG
• To: THE CORLEY CO
• Permit Index Doc Type: GENERAL CORRESPONDENCE
• Media Type: D
• Archive: No

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~`~ STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
1313 Sherman St., Room 215
Denver, CO 80203
Phone: [phone]
FAX: [phone]
December 10, 1992
Dr. W.D. Corley
The Corley Company
P.O. Box 1821
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Roy Ramer
Governor
Michael 8. Long
Division Direclar
Colorado Springs, CO 80901
RE: Citizen's Request for Inspection, Dated November 13, 1992;
G.E.C., C-81-037
Dear Dr. Corley:
The Division inspected the West Pit of G.E.C. on November 18, 1992 and
December 3, 1992, and you accompanied me on the latter inspection.
The Request for Inspection identified three issues: sizing of the
diversion ditch culvert; sizing of the extension on the culvert and
sealing of the erosional depression below the outlet of the
30" culvert. The Division's findings on each of these issues follows.
The Division reviewed Harrison Western's plans for installation of a
30" culvert which would handle flow from a 10-year 24-hour event in
the unnamed drainage. That flow was estimated at 33 cfs. The
Southfield permit application estimates the flow from both the
West Pit and the unnamed drainage at 29 cfs as part of their analysis
of their postmining topography (Volume 12, Exhibit 19, pages
142R-145R). The Division's review of the figures utilized a more
conservative curve number than that employed by Energy Fuels. In
addition, Energy Fuels assumed that the West Pit would be revegetated
to pre-mine conditions. Review of a culvert chart suggests that a
30" culvert could handle that flow with a headwater of 3.0', or 0.5'
above the top of a 2.5' culvert. Thus, the 30" culvert is adequately
sized according to the hydraulic calculations.
The 24" CMP extension is inadequately sized to handle such a flow
without substantially increasing the headwater. Harrison Western was
asked to replace it with a 30" CMP culvert on August 26, 1992. In
addition, the 30" culvert is now plugged on the inlet. Harrison
Western and the Division both signed a Compliance Agreement on
April 22, 1992 in which Harrison Western, in paragraph 23, agreed to
excavate a diversion ditch from the unnamed creek to the Magpie
Diversion by June 30, 1992. Harrison Western was asked on July 16,
1992 to re-work the diversion installation in accordance with the
approved plan. The Division is issuing N.O.V. 92-39 to effect
completion of the Compliance Agreement.