DRC-2009-006630 - 0901a068801511ff

Stateof Utah
GARY R HERBERT
Gii^'c"\(>i'
GREG BELL
LiciiU'iiiini G<ivcr>\i)r
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Department of
Environmental Quality
Amanda Smith
£.ien(Mi'C Direcior
DIVISION OF RADIATION CONTROL
Dane L Finerfrock
Diifi'lor
December 1,2009
CERTIFIED MAIL
(Return Receipt Requested)
Mr. David C Frydenlund
Vice President and General Counsel
Denison Mines (USA) Corp. (DUSA)
1050 Sevcmeenth St. Suite 950
Denver, Colorado, 80265
Subject: Apparent Chloride Plume Coincident with Lhe Nitrate Plume at the White Mesa Uranium Mill Facility
near Bianding Utah: Recommendation.
Dear Mr. Frydenlund:
After reviewing the historic chloride data for all the monitoring wells at the While Mesa Uranium Mill facility near
Bianding it appears that an apparent chloride plume is in concert with the nitrate contamination plume.
Attached to this letter is a chloride and nitrate isoconcentration map prepared by DRC staff. Chloride and nitrate data
for the chloroform investigation wells are from the l" quarter 2009 moniioring event. Because some tailing cell
compliance wells are sampled semi-annually and some quarierly, chloride and nitrate data for these wells are from the
4"" quarter 2008 or 1^' quarter 2009 monitoring events. The map shows one chloride 100 mg/L isoconcentration line
and one nitrate 10 mg/L isoconcentration line (10 mg/L is the ground water quality standard). Outside the 100 mg/L
chloride isoconcentration line, chloride concentrations range between 6-91 mg/L. Inside this isoconcentration line
chloride concentrations are the highest at the facility ranging between 113 -1010 mg/L. Both the chloride and nitrate
isoconcentration lines appear to represent plumes that are in concert with each other.
It is recommended that DUSA address and explain the chloride high concentrations in conjunction with the nitrate
contamination investigation report that is due on or before January 4, 2010.
Jf you have questions of would like to discuss these findings, please call me at 801 -536-0046.
Sincerely.
Dean C Henderson. PG
Enclosure: Map
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Figure 1
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White Mesa Site Map
ofthe Nitrate and Chloride
Plumes and Ground Water Contours
for the 1 st Quarter 2009 (March)
Samping Event
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Scale (Feet)
1000 2000 3000 4000 5000
Legend
Monitoring Wdl Witti Ninrgte and
Chloride Concern rations mg/L
Chloroform Well O
Tanimg Cell Monilor wHI 0
Piezomete' 0
niniinrt Watw r.nninur (Feell
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222
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