Colorado River Protection Activities on the

Moab UMTRA Project

Ken Pill, HydrogeologistTechnical Assistance Contractor

CMU Upper Colorado River Basin Water Forum

October 31, 2011

Site Setting

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Matheson Wetlands Preserve

Moab

Colorado River

Well Field

Tailings Pile

Evaporation Pond

Moab Wash

Site Background and Scope

Former uranium ore-processing facility 1956 to 1984 480-acre site, 130 acres covered by mill tailings pile Toe of pile is 750 ft from west bank of Colorado River Relocate 16 million tons

of uranium mill tailings to engineered disposal cell

Actively remediate ground water at Moab site• Endangered fish

species habitat protection

1984

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Ground Water Conditions

Ammonia Plume

June 2011 data Ammonia toxicity

pH and temperature dependent• Toxicity increases

at higher pH values

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Ground Water Remediation

Currently extracting ground water closer to the toe of the tailings pile

All extracted ground water pumped to a lined evaporation pond located on the top of the tailings pile

Capability to inject diverted Colorado River water into 34 injection wells along the riverbank

Ground Water Extraction

Fresh Water

Injection

Evap Pond Toe of

Tailings Pile

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Mass removal rates have increased over the past 5 years

Evaporators used to replace pile sprinkler system

As of October 2011 have removed• 699,000 lbs of ammonia• 3,200 lbs of uranium

Ground Water Remediation (continued)

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Cont

amin

ant M

ass R

emov

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Grou

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ater

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Year

Ground Water Extracted (million gal)

Ammonia (NH3) Mass Removal Rate (lbs/1,000 gal)

Uranium (U) Mass Removal Rate (lbs/100,000 gal)

Evaluating Long-Term Treatment Options Treatability study

• Russ Walker, CMU Dept of Physical and Environmental Sciences

Prepared conceptual design for chemical ground water treatment system• Golder and Assoc• pH adjustment with

lime for U ppt• Shallow settling

ponds with aeration at pH = 10.5 for NH3 removal

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Impacts of River Stage on Water Chemistry

Flow ~3,700 cfs

Base flow conditions— Gaining river

Stiff diagrams illustrate differences between water chemistry

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Impacts of River Stage (continued)

Flow ~35,900 cfs

Peak runoff conditions— Losing river

Fresh water lens migrated ~40 ft bgs and 150 ft laterally

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Fresh Water Injection

After fresh water lens developed due to runoff, supplemented with injection

Operating consistently since 2010• Have injected

9 million gallons through October 2011

Oct 2011 Ammonia (mg/L)

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Suitable Habitat Potential

Closed upstream, open downstream

After spring runoff peak through September 30

Base Flow Conditions (~3,250 cfs)

Side Channels

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Habitat Potential (continued)

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Days Habitat Present

Colorado River Flow

2011 Flooding Worked with

Utah Division of Wildlife Resources to rescue native fish from ponded water after river receded

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June 9, 201148,500 cfs

Moab Project Information

gjem.energy.gov/moab

Webcam view of Moab site

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Questions?

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