WSP10860

• File Number: 8274.400
• Description: Colorado River Basin Salinity Control - General Basinwide Salinity Issues - NPDES
• Basin: Colorado Mainstem
• Water Division: 5
• Date: 4/1/1992
• Title: Colorado River Salinity Standards Compliance at The La Plata Mine - NPDES Permit NM0029505 - New Mexico
• Water Supply Pro - Doc Type: Report/Study

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3. Evaporation Pond for Total Solar Evaporation of Mine pit
Wate-..:

In order to dispose of saline water produced at the San Juan
Mine, solar evaporation of the water provides an alternative to
treatment. Evaporation rates experienced in the La Plata, New
Mexico area indicate an average of 2.84 gallons per minute per
acre', Using a conservative rate of 2.5 gallons per minute per
acre, a pond area of 36,7 acres is required,

Assuming a construction cost of $100,000 per acre as
representative, 36.7 acres of evaporation pond area would cost
$3,670,000.

Computing an annualized payment for the pond
produces a cost of about $431,042 per year.
compared with total salt removal of 222 tons
cost per ton of salt removed becomes $1942.

for facility
When this cost is
of maximum flow, the

Conclusions

Mine pit development at the La Plata Coal Mine is planned to
intercept Fruitland Formation and La Plata Valley Alluvium ground
waters, as well as surface waters, naturally on their way to the
San Juan River. Alternatives have been outlined in this
demonstration for removal and disposal of these waters in
compliance with the Policy for Implementation of Colorado River
Salinity Standards.

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, Ralph pik$, hydrologist. National Weather Service. Personal
communication, April 12, 1991.

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