GENERAL48692

• Permit No: C1981019
• IBM Index Class Name: General Documents
• Doc Name: Proposed Decision & Findings of Compliance
• Permit Index Doc Type: General Correspondence
• Media Type: D
• Archive: No

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The following assessment of the cumulative hydrologic impacts is for all
anticipated mining in the general area of the existing Colowyo mining
operation. It was made primarily using the baseline geology and hydrology,
arxi the statement of probable hydrologic consequences contained in the
Colowyo permit application.
The Colowyo mine is the only coal mining operation anticipated in either
the surface water or ground water general area for this mine. The
Division defines "all anticipated mining" as existing mines (life-of-mine)
and those proposes mines for which permit applications have been receives.
At present, no permit applications have been received for proposed mines
in this area, so only existing operations are considered as all anticipated
mining. The other existing mining operations in the geographic area are
not expected to interact hydrologically with the Colowyor operation.
Four existing operations, the Northern Meeker mine, the Empire Energy
Eagle No. 5 and 9 mines, and the Utah International Trapper mine are all
located in the geographical vicinity of the Colowyo mine. The Northern
Meeker mine is located in the White River watershed, and is, therefore,
not hydrologically adjacent with respect to surface water and alluvial
ground water. The Empire Energy Eagle mines and the Utah International
Trapper mine are located within the Yampa River drainage, as is the
Colowyo mine. However, the Colowyo operation is located approximately
seven miles south of the Yampa River. Runoff from the mine site flows
to one of three receiving streams (Good Spring Creek, Taylor Creek, and
Wilson Creek), which flow to Milk Creek, a tributary to the Yampa River.
Alttnugh the Colowyo operation may affect receiving streams, no measureable
effect is anticipated upon either the quantity:or~ quality of surface flow
or alluvial ground water in the Yampa River (see discussion of Probable
Hydrologic Consequences, pages 22-25 ). Therefore, the Colowyo mine is
not expected to interact hydrologically with respect to surface water or
alluvial ground water with the other mines 1•ocat~ within the Yampa River
drainage.
No regional bedrock aquifer exists within the strata to be affected by the
Colowyo mining operation. Only a limited amount of bedrock ground water
exist.~in the area, and it exists as small, laterally discontinuous,
perched aquifers. The closest regional aquifer is the Trout Creek sandstone;
which is approximately 800 feet below the lowest coal seam to be mined.
Mining at Colowyo is not expectc~I to affect this aquifer. The Colowyo
mining operation is, therefore, considered isoloated with respect to its
bedrock ground water effects, and would not be expected to interact with
the other mines in the geographical vicinity.
Probable Hydrologic Consequences - Sufface Water
The following discussion of the probable hydrologic consequences of the
proposed operation is based upon_ th_e discussion provided by the applicant
_(pp. 2.04-81 to 2.04.91 of thetAay 24, 1982 Colowyo Coal Company Response
to Draft Findings and 5tipula.tions).