HYDRO30463

• Permit No: C1982056
• IBM Index Class Name: Hydrology
• Doc Date: 7/13/2007
• Doc Name: Ground Water Points of Compliance Determination
• From: DRMS
• To: File
• Permit Index Doc Type: Other Ground Water
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman S[., Room 215
Denver, Colorado 80203 C O L O R A D O
Phone: [phone] u t v I s t o N o f
RECLAMATION
FAX: [phone] M I N I N G
- &-
SAFETY
MEMO
Bill Ritter, lr.
Date: June 13, 2007 Governor
Harris D. Sherman

From: Tom Kaldenbach Executive Director
Ronald W. Cattany
Division Director
T0: Flie Natural Resou¢e Trustee
Foidel Creek Mine (Permit C-82-056)
Hydrology
Re: Ground Water Points of Compliance Determination
I have reviewed the need for establishing ground water points of compliance at the Foidel
Creek Mine. I reviewed the mine's past annual hydrology reports and hydrogeologic
maps in the permit application.
Rule 4.05.13 requires establishment of ground water points of compliance if the mine has
the potential to negatively impact ground water for which quality standards have been
established by the Water Quality Control Commission. I have concluded that ground
water points of compliance are warranted at the Foidel Creek Mine for alluvial ground
water, but not for bedrock ground water, as explained below-
Alluvial Ground Water - Pumping of underground mine water that is relatively high in
dissolved solids could migrate into ground water in the alluvium of Foidel Creek or Fish
Creek. TDS of underground mine water has been a few thousand mg/I compared to less
than 1,500 mg/1 in many of the alluvial water samples. The following three existing
wells would fulfill the need for alluvial ground water points of compliance: 008-AV-2
(Foidel Creek alluvium), 008-AU-3 (Fish Creek alluvium), and 008-AT-1 (Trout Creek
alluvium).
Bedrock Ground Water -The underground mine workings of the Foidel Creek Mine are
developed in the axial areas of the Twentymile Park Syncline and a southern extension of
the Hayden Syncline (USGS Water-Resources Investigations Report 90-4020 shows the
synclinal axes). In order for gob leachate to adversely impact bedrock groundwater
quality in all but the southwestern part of the permit area, the leachate would have to
migrate up the flanks of the synclines through the coal seam beyond the affected area of
the mine. In these areas, migrating leachate would not make it beyond the affected area
because it would discharge to the ground surface from the coal outcrop that extends
around the flanks of the synclines. In the southwestern part of the affected area,
excavation of the workings on the eastern flank of the southern extension of the Hayden
Syncline would have promoted eastward ground water migration across the synclinal axis
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