_GENERAL DOCUMENTS - C1981017 ‎(251)‎

• Permit No: C1981017
• IBM Index Class Name: GENERAL DOCUMENTS
• Doc Name: Bid Documents ‎(IMP)‎ 1993 Correspondence
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources ��oF cow
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1313 Sherman St.,Room 215 •
Denver,CO 80203
Phone:[phone]
*1876
FAX:[phone] Roy Romer
Governor
Michael B.Long
Division Director
DATE: October 13, 1993
TO: Steve Renner
FROM: Kent Gorham
4,
RE: Coal Basin, September 9, 1993 Water Sample Results
I have reviewed the data from 6 samples collected by the Office of
Surface Mining on September 9, 1993 at the Coal Basin Mine. My
comments are as follows:
1. The water quality upstream of mining would be classified a soft,
sodium-bicarbonate water with total dissolved solids of
approximately 110 ppm.
2 . Downstream of the mine and the influenced tributaries, water
quality changes to hard, sodium-sulfate water with total dissolved
solids in the range of 775 ppm.
3 . The downstream water exceeds the drinking water standard for TDS
(500 ppm) and sulfate (250 ppm) . However, it should be noted that
use as drinking water may not occur for many miles downstream and
if so drinking water standards would not be an appropriate measure
until water is taken from the stream system for that use.
4. Heavy metals were not at a concentration of concern compared
drinking water standards. The pH was consistently alkaline with
the exception of the refuse pile drainage which was nearly neutral
(7.2) .
Copper, mercury, and silver aquatic life standards are more
stringent than drinking water standards. Silver is not included in
the parameters analyzed. Copper and mercury are below the
detection limit of the testing facility.
5 . These data show the mine runoff and/or discharge do affect the
stream system within the immediate area. How far downstream these
affects are evident and whether they are at suspect levels for
material damage cannot be determined from these data. Based on
comparison of discharge and initial loading estimates these samples
would appear to be a fair representation of water quality during
low-flow.