APPCOR12894

• Permit No: C1982056
• IBM Index Class Name: Application Correspondence
• Doc Date: 4/1/1983
• Doc Name: ADDENDUM TO RATIONALE COLO YAMPA COAL CO PN CO-0027154 ROUTT CNTY
• Media Type: D
• Archive: No

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COLORADO DEPARTMENT OF HEALTH
Water Quality Control Division
4210 East 11th Avenue
Denver, Colorado 80220
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ADDENDUM TO RATIONALE
COLORADO YAMPA COAL CO.
PERMIT NUMBER: CO-0027154
ROUTT OOUNTY
APR 011983
MINED LAND RECLAMATION
Colo. Dept. et Natural Resources
The permittee subml[ted a letter dated January 13, 1983 informing the Division
that the permittee is planning to expand operations and perform underground
coal mining at the site. Water from the underground mine would be pumped to a
sump. From the sump the water would be pumped to pond D, and to Foidel Creek
through permitted discharge point 005.
Presently, discharge point 005 has technology based, federal effluent
limitations (BPT) for iron and total suspended solids. These limitations were
placed in the permit because the pond was designed [o contain runoff from
surface mining activities associated with Mine lll. Discharges of runoff from
the pond coincided with high in-stream flows and it is the Division's position
that under these circumstances more stringent limitations are not required to
maintain instream water quality standards.
The proposed underground mine is expected to produce more water than occurred
from the surface mine. In addition, the drainage from the underground mine
would occur over all seasons of the year, not just in response to
precipitation events. Based on the projections submiCted by the permittee,
flows from the underground mine will increase from 49 gpm in the 1st year of
mining to over 1600 gpm in the 4th year. These rates of flow from the mine
will result in a continuous or nearly continuous discharge of water from 005
by January 1, 1984.
Pond D which has discharge point 005 as it's outfall has a total capacity of
approximately 51 acre-ft. of water without using the emergency spillway.
Based on the calculations of the DILRD, the pond needs 23.6 acre -f t, of storage
to handle sediment. This is a conservative figure and subject to change.
However, iC is a requirement of MLRD at this moment. In addition, 6.7
acre-f t. of storage is required to handle runoff from the 10 year-24 hour
storm event. In total, 30.3 acre-f t. of storage is needed for sediment and
runoff without considering the underground mine drainage. Thus, 20.7 acre-f t.
of storage is available for underground mine drainage.
Drainage from the underground mine is projected to be .19 acre-f t./day in year
one, 3.3 acre-f t./day in year two and reaching 7.2 acre-ft./day in year four.
In year two there would be approximately 6 days of storage available, in year
four, only 3 days of storage. Currently the pond is designed to discharge
almost continuously as water is collected. At the volumes of water projected
to flow from the mine a continuous discharge would occur. Since a continuous
discharge will occur instream water quality standards must be protected in the
permit.