1993-11-15_GENERAL DOCUMENTS - C1981017

• Permit No: C1981017
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Date: 11/15/1993
• Doc Name: Bid Documents ‎(IMP)‎ Hydrology Correspondence Part ‎(2 of 2)‎
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

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CF Cp) 5TATE OF COLORADO
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+� Q j i.; Roy Romer, Governor
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DEPARTMENT OF NATURAL RESOURCES tx�
MINED LAND RECLAMATION DIVISION Y'
FRED R. BANTA, Director
January 25, 1989
Ms. Diane Delaney
Mid-Continent Resources, Inc.
201 Centennial Street, Suite 406
Glenwood Springs, Colorado 81601
RE: Coal Basin Mine, C-017-81 , Annual Hydrologic Report
Dear Ms. Delaney:
I have reviewed the 1988 annual hydrologic report and annual report for the
mine. Overall , no unexpected impacts are shown from the '88 monitoring. I
have detailed below areas of special interest.
The October, 1988 samples for both Dutch and Coal Creek have elevated levels
of Total Dissolved Solids (TDS) over previous years. By calculating the TDS
from the major cations and anions present, I find little error so the level
appears accurate. This elevated level of TDS could be an effect of the
back-to-back low water years as noted in your report, but could also be
affected by the elevated level of TDS present in the mine water discharge.
All these sites should be watched in future years to see if the trend toward
elevated TDS continues. The placement of on line desanders on the mine water
discharge as previously proposed by Mid-Continent would probably help to
alleviate the increased level of TDS in the mine water.
The 8/7/86 TDS level noted for Bear Creek is incorrect. I believe a search
tnrough your records will show correspondence with the ACZ Laboratories, where
they recalculated and gave a much lower level of TDS. My own calculated TDS
is 95 mg/l . The ACZ number should be in this range.
It appears that during the technical revision which changed the monitoring
plan, a TDS requirement for laboratory analysis was left out of the
groundwater portion. A laboratory determined TDS is important both to check
the field conductivity and to check laboratory values of all major cations and
anions. The addition of this element for analysis for should be committed to
by sending a replacement page for the permit application.
The Sutey refuse area wells show elevated TDS in 1988. However, little or no
seepage is expected from the pile due to compaction and presence of an
underdrain. The underdrain which carries a large of portion of water under
the pile is showing relatively good quality with a TDS of around 600 mg/l .
215 Centennial Building, 1313 Sherman Street Denver, Colorado 80203-2273 Tel.[phone]