REP00790

• Permit No: C1982056
• IBM Index Class Name: Report
• Doc Date: 5/26/1987
• Doc Name: 1986 AHR Evaluation
• From: Cathy Begej
• To: File
• Annual Report Year: 1986
• Permit Index Doc Type: Hydrology Report
• Media Type: D
• Archive: No

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STATE OF COLORADO
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Roy Romer, Governor
DEPARTMENT OF NATURAL RESOURCES
MINED LAND RECLAMATION DIVISION
DAVID C. SNELTON, Director
DATE: May 26; 1987
T0: Hydrology File, Foidel Creek Mine, File No. C-82-056
FROM: Cathy Begej ~
C~
RE: EVALUATION OF 1986 AHR, FOIDEL CREEK MINE
INTRODUCTION:
The Foidel Creek Mine is impacting the hydrologic balance of the area through
its dewatering of the Wadge coal aquifer and the subsequent discharge to
Foidel Creek. Dewatering of the Wadge coal aquifer has simultaneously
accelerated the migration of a saline spoils plume from the adjacent surface
mine; resulting in mine discharge waters which reflect spoils quality, rather
than unaffected Wadge overburden quality. Foidel Creek, ephemeral above the
mine, is currently experiencing perennial discharge.
In 1986, mine discharge waters averaged 0:26 cfs, slightly lower than the
maximum projected discharge from the Foidel Creek portals of 0.278 cfs. TDS
levels in 1986 were similar to levels observed throughout the three-year
monitoring period. These waters mix with surface water runoff from the
adjacent surface mine; and result in a discharge which has ten percent fewer
dissolved solids than the mine discharge itself. Previous years, and in the
future; this pond will also include contributions from the Area 2 Pit. This
pit is fed exclusively by backfilled spoils and in 1986 had TDS levels
approximately 1000 mg/1 higher than the mine discharge water. Consequently,
the quality of effluent from Pond D should deteriorate once the Area 2 Pit
begins to discharge:
SURFACE WATER
Foidel Creek Drainage
Foidel Creek baseline is best derived from site 14, an upstream site on the
north fork of Foidel. The drainage has not been affected by mining. This
ephemeral drainage flow has historic flow ranging from 0 - 11:6 cfs with no
flow periods occurring in late summer and mid-winter: The slightly alkaline
calcium sulfate water has a high hardness (x = 410 mg/1) and an average
salinity of 635 mg/1 TDS: Mean iron, manganese, and sulfate concentrations
are higher than material damage suspect levels. Total iron levels average 1.
mg/1 and range from 0:01 - 13:80 mg/1. The aquatic life standard is 1 mg/1.
Total manganese levels average 0.2 mg/1 and range from 0.01 - 19.2 mg/1. The
irrigation stock watering level is 0.2 mg/1.
423 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel. [phone]