HYDRO23967

• Permit No: C1981019
• IBM Index Class Name: Hydrology
• Doc Date: 11/30/1998
• Doc Name: RESPONSE TO COMMENTS ON DRAFT PERMIT COLOWYO COAL CO LP CDPS CO-0045161 FORMERLY COG-850017 MOFFAT C
• From: WQCD
• To: DMG
• Permit Index Doc Type: CORRESPONDENCE
• Media Type: D
• Archive: No

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STATE OF COLOI~1llU

Roy Romer, Governor
Paoi Shwayder, Executive Director
t7edica[ed to protecting and improving the health and environment olthe people o(Colorado
4300 Cherry Creek Dr. 5. Laboratory and Radiation Services Division
Denver, Colorado 80246.1530 8100 Lowry Blvd.
Phone [phone] Denver CO 80220-6928
Located in Glendale, Colorado 1303) 692-3090
h «p://svww.cdphestate.co.us
Water Quality Control Division
WQCD-P-B2
[phone] FAX [phone]
November 27, 1998
Daniel I. Hernandez
Senior Environmental Protection Specialist
Colorado Division of Minerals and Geology
1313 Sherman Street, Room 215
Denver, CO 80203
RE: Response to Comments on Draft Permit
Colowyo Coal Company L.P. - Colowyo Coal Mine
CDPS No. CO-0045161 (pending) (formerly COG-85001'n
Moffat County
Dear Mr. Hernandez:
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Colorado Department
of Public Health
and Etmmnment
RECEIVED
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rivision of Minerals & Geology
The Water Quality Control Division is finalizing modifications to the new draft permit for Colowyo Coal
Company L.P. Thank you for your comments on this draft permit. This letter responds to your January 12,
1998, letter in full. At your request, we had previously submitted a partial response dated February 20, 1998.
This letter may repeat these responses where they are still applicable. We will also respond to the followup
letter dated February 27, 1998, that you submitted in response to our letter. Our responses will reference the
numbering used in your letters.
JANUARY 12. 1998 LETTER
A. Permi
1. The Division has made the decision to exempt surface runoff discharges at this time from whole effluent
toxicity testing requirements irrespective of the source of the runoff. Our position is based on these
factors:
a. Iron is the primary constituent with the potential for toxicity in most coal mining facility surface runoff
discharges. Iron is much less toxic than other metals -the toxicity level for aquatic life is much higher;
b. We have found that contact time is important, since oxidation is needed to significantly increase the
concentration of iron in a discharge. This is our position for requiring WET testing for discharges
from pits, we believe the likelihood for extended contact with the coal seam exists for water pumped
from pits since it is likely to remain in a pit until the operator needs to remove it to facilitate mining;
c. Surface runoff discharges are expected to occur when stream flows are high and instream quality is
deteriorated by non-point source pollution and other sources. Also, we would expect temperatures of
surface runoff (especially snowmelt) to be typically lower than the temperature of pit water. This
would slow oxidation. It would be unreasonable to require permittees to construct treatment facilities
to enable them to assure compliance with WET limitations, if this became necessary, since the flow
volumes are unpredictable and sometimes quite large.