GENERAL32987

• Permit No: C1981044
• IBM Index Class Name: General Documents
• Doc Date: 3/2/1984
• Doc Name: Revised Proposed Decision & Findings of Compliance
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

-43- ~I~-~ ~\ ~ tl
Cumulative Ground Water Impacts
The proposed Sugarloaf Mine is hydrologically adjacent to the Empire Energy
Eagle No. 5 Mine in that they share a common geologic structural/ground water
basin, the Round Bottom Synclinal Basin. Impacts to regional rock aquifers
at both mines may produce cumulative ground water quality and quantity impacts
within the basin. A quantification of cumulative impacts is impossible at
this time, given the lack of baseline data on the Round Bottom Syncline at
both mines. However, qualitative assessments can be made of cumulative
hydrologic impacts of the mines.
The cumulative ground water quantity impacts of the Sugarloaf and Empire
Energy Mines are expected to be minimal in the regional aquifers of the Round
Bottom because the proposed Sugarloaf Mine is located on the northwestern edge
of the syncline and the Empire Energy Mines are located on the southeastern
edge; eleven miles separate these mines. Additionally, these two mines are
separated by the Yampa River, which is a recharge boundary. Therefore, the
impacts of the two mines on the quantity of ground water will be concentrated
in separate segments of the Round Bottom Synclinal Basin and cumulative
impacts to the entire basin is anticipated to be minimal.
The Sugarloaf and Empire Energy Mines may impact the quality of ground water
in regional rock aquifers in the Round Bottom Synclinal Basin. However, given
the distance between the mines and given the presence of the Yampa River
between the mine sites, the cumulative ground water impacts is anticipated to
be negligible.
Empire Energy Corporation's Eagle No. 9 Mine and the Trapper surface mine will
impact the quality and quantity of ground waters in the Upper Williams Fork
Formation and the Big Bottom alluvium.
The quantity of ground water will be impacted by the two mines in the first
White sandstone (referred to as the third White sandstone at the Trapper Mine)
of the Williams Fork Formation. The quantity of ground water will be impacted
during and shortly after cessation of mining at the two mines. The Trapper
Mine will mine through a portion of the recharge area of this aquifer and the
Eagle No. 9 Mine will deplete the ground water stored in the aquifer through
mine inflows. The combfned quantity impact will be a lowering of ground water
levels in wells completed in the First White sandstone and a reduction in
discharge rates of springs and seeps issuing from this aquifer.
The Eagle No. 9 Mine will not impact the ground water quality in and the
discharges from the first White sandstone during mining. The Ea91e No. 9 Mine
will receive discharges from adjacent aquifers during mining and will not
discharge to these aquifers during mining, due to the hydrologic pressures.
The Eagle No. 9 Mine may significantly impact the quality of ground water in
the first White sandstone and other overlying and underlying aquifers once
mining has ceased. Mine waters from the Eagle No. 9 Mine could flow from the
mine workings to the first White sandstone through the demonstrated
communication between aquifers and mine workings.