1994-10-19_PERMIT FILE - M1994093

• Permit No: M1994093
• IBM Index Class Name: Permit File
• Doc Date: 10/19/1994
• Doc Name: DAHLIA NORTH RESOURCES PIT MLRB 112 PERMIT APPLICATION CITY OF COMMERCE CITY CNTY OF ADAMS COLORADO
• Media Type: D
• Archive: No

EXHIBIT .-i - WATER IN OR ATION NARRATIVE (CONTINUED)
Water Requirements
Ground water will be consumed by evaporation, water in the product,
and washing. A substitute water supply plan will be submitted to
the State Engineer to replace depletions resulting from the mining
activity.
• Evaporation will occur from exposed ground water on the site .
Water will be exposed in the base of the dewatered, active mining,
and the wet mined areas . During the first two years of operation,
the only water surface exposed will be residual water in the base
of the dewatered pit . Based on 2 acres of exposed water, the
1, depletion is estimated at 5 acre feet per year. The estimated
maximum permanent water surface of the wet mined area will be 22
acres . The evaporation at the maximum mining stage, and the
maximum after reclamation, will be approximately 55 acre feet per
year.
The amount of water retained in the product is estimated at 41 by
• weight . Based on production of 1, 000, 000 tons per year the amount
of water consumed by removing wet product is approximately 26 acre
feet per year. The washing will require approximately 1, 000
gallons per minute . Washing will occur at the Thornton Plant,
where the material is transported by conveyor. The Thornton Pit
has a substitute plan in place, and depletions from the washing
• process will be accounted and replaced within that plan.
In summary, the estimated water consumption prior to the start of
the wet mining is as follows :
Tyne of Use Annual Consumption (acre feet)
•
Evaporation 5 . 0
Product and wash water 26 . 0
Total 31 . 0
• Once wet mining begins, the water consumption from evaporation will
be 2 . 5 acre feet for each acre of water exposed.
When reclaimed, a 110 acre surface area lined reservoir, and up to
a 22 acre surface area unlined lake, will occupy the site . No
water will be consumed by the liner reservoir. Therefore, no
• augmentation plan will be required for the lined reservoir, but up
to 55 acre feet of water will be required to replace evaporative
losses from a maximum size 22 acre unlined surface lake area,
located east of the Bull Seep Ditch.
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