DRC-2011-001869 - 0901a06880202361

DRC-2011-001869
Denison Mines (USA) Corp.
1050 17th Street, Suite 950
DENISON ^i^^ USA
I N E S Tel : [phone]
Fax : [phone]
www.denisonmines.com
February 14,2011
VIA HAND DELIVERY AND PDF
Rusty Lundberg,
Co-Executive Secretary
Utah Water Quality Board
Utah Department of Environmental Quality
195 North 1950 West
P.O. Box 144850
Salt Lake City, UT 84114-4850
Re: State of Utah Ground Water Discharge Permit No. UGW370004
White Mesa Uranium Mill - Notice Pursuant to Part I.G.I (a)
Dear Mr. Lundberg:
The White Mesa Mill (the "Mill") performed fourth quarter ("Q4") groundwater monitoring
during the period from October 19, to December 15, 2010 under the June 17, 2010 version of the
Mill's Groundwater Discharge Permit (the "GWDP"). All analytical data needed for comparison
to the GWCLs was received during the period ending January 14, 2011.
Pursuant to Part I.G.l.a) of the GWDP, please take notice that the concentrations of specific
constituents in the monitoring wells highlighted in yellow and bold italics in the columns for the
fourth quarter in the attached Table 1, exceeded their respective GWCLs. For ease of review.
Table 1 has been formatted to simplify the tracking of any continued exceedances from one
monitoring period to the next by charting ongoing monitoring of the same well in the same row,
and by highlighting exceedances (in color and bold italics).
Under the June 17, 2010 revisions of the GWDP, GWCLs have been determined on a well-by-
well basis to reflect background groundwater quality, as defined by the mean plus second
standard deviation concentration, or the equivalent. Accordingly, the GWDP requires that
constituent concentrations in each monitoring well shall not exceed the GWCLs set out in Table
2 of the GWDP. It should be noted that, because the GWCLs have been set at the mean plus
second standard deviation, or the equivalent, un-impacted groundwater would normally be
expected to exceed the GWCLs approximately 2.5% of the time. Therefore, exceedances are
expected in approximately 2.5% of all sample results, and do not necessarily represent impacts to
groundwater from Mill operations.
Page 1
The following are items of note relevant to all exceedance data presented herein:
1. Nitrate -i- nitrite and chloride in monitoring wells at the site are the subject of an ongoing
investigation. In the December 30, 2009 Nitrate Contamination Investigation Report,
prepared by Intera, Inc., Intera has concluded that the elevated nitrate -f- nitrite and
chloride concentrations observed at the Mill resulted from sources unrelated to the Mill's
operations. Denison is in the process of proposing additional investigations to confirm the
source(s) of these constituents.
2. As discussed in previous quarterly groundwater sampling reports, the background levels
and GWCLs for pH were established based on eight or more quarters of laboratory data,
which are historically higher than field data due to effects from the evolution of carbon
dioxide, and subsequent increase in pH from field to lab. Denison Mines (USA) Corp.'s
(Denison's) letter to the Co-Executive Secretary of the Utah Water Quality Board dated
January 31, 2011 proposed the recalculadon of the GWCLs for field pH. The proposal
requests the recalculation of the GWCLs based on a statistical analysis of actual field
data, which is expected to result in somewhat lower GWCLs for pH in most wells.
1.0 Required Quarteriy Sampling Wells
As indicated in the attached Table 1, the analytes discussed below exceeded their respective
GWCLs for two successive sampling periods during the fourth quarter. One time exceedances
are noted on Table 1, but not discussed below. Successive exceedances which occurred in
previous reporting periods are discussed in the respective Exceedance Notice for that quarter.
MW-11
Manganese has been slightly outside (slightly higher than) the GWCL in MW-11 in the
October, November (Q4) and December sampling events.
MW-14
Field pH has been slightly outside (slightly lower than) the GWCL in MW-14 in the
October, November (Q4) and December sampling events.
MW-26
Chloroform in MW-26 has exceeded its GWCL for all of the monitoring periods for
2010. MW-26 is used as a pumping well for the ongoing chloroform capture program
and is expected to yield increased concentrations of chloroform.
Methylene chloride exceeded its GWCL in the October monthly and November (Q4)
sampling events.
Page 2
MW-26 Note: As stated in the September 2009 Statement of Basis (page 23) in support of the
January 20, 2010 revisions to the GWDP, "[i]t should be noted that, because MW-26 is a
pumping well for chloroform removal, concentrations of all constituents in that well are subject
to potential variation over time as a result of the pumping activity. This will be taken into
account by the Executive Secretary in determining compliance for this well."
MW-30
• Nitrate -i- nitrite concentrations exceeded its GWCL in all sampling events during the
fourth quarter 2010.
MW-31
• Nitrate -I- nitrite concentrations exceeded its GWCL in all sampling events during the
fourth quarter 2010.
1.1 New Exceedances Reported in Q4
New exceedances for the quarterly well sampling program are listed below. The exceedances
listed will result in an accelerated sampling frequency from quarterly to monthly. It is important
to note that the wells listed below will only be sampled for those constituents which exceeded the
GWCLs during the monthly events. The wells listed below will be sampled for all constituents
listed in the GWDP during the quarterly events as that is the regularly scheduled sampling for the
quarterly wells.
• Gross alpha in MW-26 exceeded the GWCL in the Q4 sampling event in November
2010. It is important to note that these data are considered suspect. The Method
Blank associated with the entire analytical batch of samples reported elevated
concentrations of Gross Alpha minus RN & U. Denison has requested reanalysis of
this analytical batch since it is still within the QAP required holding time of 6 months.
The data will be reported in the Quarterly Report due March 1, 2011. A letter detailing
the results ofthe reanalysis will follow under separate cover upon receipt ofthe
reanalysis.
• Sulfate in MW-31 exceeded its GWCL in the Q4 sampling event in November 2010.
2.0 Semiannual Sampling Wells Accelerated to Quarterly
As indicated in the attached Table 1, the analytes discussed below exceeded their respective
GWCLs for two successive sampling periods (Q3 and Q4).
MW-3
• Field pH has been slightly outside (slightly lower than) the GWCL for both the Q3
sampling event and the Q4 sampling event.
Page 3
MW-3A
• Field pH has been slightly outside (slightly lower than) the GWCL for both the Q3
sampling event and the Q4 sampling event.
MW-12
• Selenium has exceeded the GWCL for both the Q3 sampling event and the Q4 sampling
event.
MW-18
• Thallium has exceeded the GWCL for both the Q3 sampling event and the Q4 sampling
event.
MW-19
• Field pH has been slightly outside (slightly lower than) the GWCL for both the Q3
sampling event and the Q4 sampling event.
MW-23
• Field pH has been slightly outside (slightly lower than) the GWCL for both the Q3
sampling event and the Q4 sampling event.
MW-24
• Field pH has been slightly outside (slightly lower than) the GWCL for both the Q3
sampling event and the Q4 sampling event.
• ThaUium has exceeded the GWCL for both the Q3 sampling event and the Q4 sampling
event.
• Cadmium has exceeded the GWCL for both the Q3 sampling event and the Q4 sampling
event.
MW-27
• Nitrate -l- Nitrite have exceeded the GWCL for both the Q3 sampling event and the Q4
sampling event.
• Chloride has exceeded the GWCL for both the Q3 sampling event and the Q4 sampling
event.
MW-28
• Field pH has been slightly outside (slightly lower than) the GWCL for both the Q3
sampling event and the Q4 sampling event.
• Chloride has exceeded the GWCL for both the Q3 sampling event and the Q4 sampling
event.
MW-32
• Field pH has been slightly outside (slightly lower than) the GWCL for both the Q3
sampling event and the Q4 sampling event.
2.1 New Exceedances Reported in Q4
New exceedances for the semi-annual well sampling program are listed below. The exceedances
listed will result in an accelerated sampling frequency from semi-annually to quarterly. It is
important to note that during the first and third quarterly events the wells listed below will only
Page 4
be sampled for those constituents which exceeded the GWCLs because the first and third
quarterly events do not include the semi-annual well sampling program. The wells listed below
will be sampled for all constituents listed in the GWDP during the second and fourth quarter
events as that is the regularly scheduled sampling for the semi-annual wells.
• Gross alpha in MW-2 exceeded the GWCL in the Q4 sampling event in November 2010.
It is important to note that these data are considered suspect. The Method Blank
associated with the entire analytical batch of samples reported elevated concentrations
of Gross Alpha minus RN & U. Denison has requested reanalysis of this analytical
batch since it is still within the QAP required holding time of 6 months. The data will
be reported in the Quarterly Report due March 1, 2011. A letter detailing the results of
the reanalysis will follow under separate cover upon receipt ofthe reanalysis.
• Selenium in MW-3A exceeded its GWCL in the Q4 sampling event in November 2010.
• Uranium in MW-5 exceeded its GWCL in the Q4 sampling event in November 2010.
• Gross alpha in MW-27 exceeded the GWCL in the Q4 sampling event in November
2010. It is important to note that these data are considered suspect. The Method
Blank associated with the entire analytical batch of samples reported elevated
concentrations of Gross Alpha minus RN & U. Denison has requested reanalysis of
this analytical batch since it is still within the QAP required holding time of 6 months.
The data will be reported in the Quarterly Report due March 1, 2011. A letter detailing
the results ofthe reanalysis will follow under separate cover upon receipt ofthe
reanalysis.
If you have any questions or require any further information, please contact the undersigned.
Yours truly,
Jo Ann Tischler
Director, Compliance and Permitting
cc: David C. Frydenlund
Ron Hochstein
Harold Roberts
David Turk
Ryan Palmer
Central Files
Page 5
Table 1 - GWCL Exceedances for Fourth Quarter 2010 under the June 17, 2010 GWDP
Ql Results Q2 Results Q3 Results Q4 Results
Monitoring
Well
(Water
Class)
Constituent
Exceeding GWCL
GWCL in
Jun 17,
2010
GWDP
Ql
Sample
Date
Ql Result
Q2
Sample
Date
Q2
Result
May
Monthly
Sample
Date
May
Monthly
Result
June
Monthly
Sample
Date
June
Monthly
Result
July
Monthly
Sample
Date
July
Monthly
Resuh
August
Monthly
Sample
Date
August
Monthly
Resuh
Q3
Sample
Date
Q3
Result
October
Monthly
Sample
Date
October
Monthly
Result
Q4
Sample
Date
Q4
Result
December
Monthly
Sample
Date
December
Monthly
Result
Sample
Frequency
Required Quarterly Sampling Wells
MW-11
(Class II)
Manganese (ug/L) 131.29 2/10/10 134 4/28/10 137 5/24/10 122 6/16/10 99 7/20/10 123 8/25/10 138 9/8/10 128 10/20/10 141 11/11/10 133 12/15/10 75* Quarterly MW-11
(Class II) Tetrahydrofuran (ug/L) 11.5 2/10/10 12 4/28/10 5.2 5/24/10 <1.0 6/16/10 <1.0 7/27/10 2.17 8/25/10 <1.0 9/8/10 <1.0 10/20/10 <1.0 11/11/10 <1.0 12/15/10 <1.0 Quarterly
MW-14
(Class III) Field pH (S.U.) 6.5 - 8.5 2/2/10 6.46 4/21/10 6.29 5/21/10 6.94 6/16/10 7.03 7/20/10 6.36 8/25/10 6.45 9/8/10 6.29 10/20/10 6.36 11/10/10 6.29 12/15/10 6.45 QucUterly
MW-25
(Class III) Uranium 6.5 2/26/2010 5.93 4/28/2010 6.43 NS NA NS NA NS NA NS NA 9/8/2010 6.57 NS NA 11/10/10 5.89 NS NA Quarterly
MW-26
(Class III)
Nitrate -i- Nitrite (as N)
(ms/L) 0.62
2/2/10
1.3
4/22/10
2
5/21/10
0.3
6/I6/I0
0.4
7/21/10
0.6
8/16/10
0.6
9/26/10
0.7
10/20/10
0.4
11/15/10
0.2
12/15/10
0.4 Quarterly
MW-26
(Class III)
Uranium (ug/L) 41.8
2/2/10
58.7
4/22/10
66.7
5/21/10
37.4
6/I6/I0
36.6
7/21/10
34.4
8/16/10
71.8
9/26/10
72.7
10/20/10
37.5
11/15/10
30.4
12/15/10
29.6 Quarterly
MW-26
(Class III)
Chloroform (ug/L) 70
2/2/10
700
4/22/10
1700
5/21/10
800
6/I6/I0
940
7/21/10
900
8/16/10
2800
9/26/10
2100
10/20/10
1000
11/15/10
1900
12/15/10
1400 Quarterly
MW-26
(Class III)
Chloride (mg/L) 58.31
2/2/10
72
4/22/10
57
5/21/10
80
6/I6/I0
47
7/21/10
52
8/16/10
49
9/26/10
64
10/20/10
52
11/15/10
48
12/15/10
52 Quarterly
MW-26
(Class III)
Field pH (S.U.) 6.74 - 8.5 2/2/10 6.59 4/22/10 7.16 5/21/10 7.08 6/I6/I0 7.05 7/21/10 6.36 8/16/10 6.98 9/26/10 7.18 10/20/10 6.36 11/15/10 7.18 12/15/10 6.98 Quarterly MW-26
(Class III) Dichloromethane
(Methylene Chloride)
fue/L)
5
2/2/10
1
4/22/10
9.9
5/21/10
NR
6/I6/I0
2.2
7/21/10
12
8/16/10
24
9/26/10
45
10/20/10
5.5
11/15/10
16
12/15/10
1.2 Quarterly
MW-26
(Class III)
TDS (mg/L) 3284.19
2/2/10
3100
4/22/10
3280
5/21/10
NS
6/I6/I0
NS
7/21/10
NS
8/16/10
NS
9/26/10
3440
10/20/10
NS
11/15/10
3140
12/15/10
NS Quarterly
MW-26
(Class III)
Gross Alpha minus Rn
& U (pCi/L) 4.69
2/2/10
2.4
4/22/10
0.6
5/21/10
NS
6/I6/I0
NS
7/21/10
NS
8/16/10
NS
9/26/10
2.5
10/20/10
NS
11/15/10
6.4
12/15/10
NS Quarterly
MW-30
(Class II)
Nitrate -i- Nitrite (as N)
(mg/L) 2.5 2/9/10 16.1 4/27/10 /5.« 5/21/10 17 6/15/10 15.3 7/21/10 16 8/24/10 16 9/15/10 75 10/19/10 75 11/9/10 15 12/14/10 16 Quarterly MW-30
(Class II) Selenium (ug/L) 34
2/9/10
32
4/27/10
35.3
5/21/10
NS
6/15/10
NS 7/27/10 33.5 8/24/10 35.6
9/15/10
32.6
10/19/10
32.4
11/9/10
32.2
12/14/10
30.5 Quarterly
MW-31
(Class III)
Nitrate + Nitrite (as N)
(mg/L) 5
2/9/10
21.7
4/20/10
22.5 5/21/10 23 6/15/10 21.1 7/21/10 20 8/24/10 22
9/13/10
21 10/19/10 20
11/9/10
20
12/14/10
20 Quarterly MW-31
(Class III) TDS (mg/L) 1320 2/9/10 1150 4/20/10 1220 NS NA NS NA NS NA NS NA 9/13/10 1330 NS NA 11/9/10 1320 12/14/10 NS Quarterly
Quarterly
MW-31
(Class III)
Sulfate (mg/L) 532
2/9/10
507
4/20/10
522 NS NA NS NA NS NA NS NA
9/13/10
527 NS NA
11/9/10
539
12/14/10
NS
Quarterly
Quarterly
Req uired Semi-Annual SampUng Wells
MW-2
(Class III)
Gross Alpha minus Rn
& U (pCi/L) 3.2 NS NA 4/27/10 1.2 NS NA NS NA NS NA NS NA NS NA NS NA 11/17/10 5.5 NS NA Semi-Annually
MW-3
(Class III)
Selenium (ug/L) 37 NS NA
5/3/10
37.2 NS NA NS NA NS NA NS NA
9/20/10
35.5 NS NA
11/19/10
38.8 NS NA Semi-Annually MW-3
(Class III) Field pH (S.U.) 6.5 - 8.5 NS NA 5/3/10 6.14
(6.25) NS NA NS NA NS NA NS NA 9/20/10 6.14 NS NA 11/19/10 6.14 NS NA Semi-Annually
MW-3
(Class III)
Fluoride (Mg/L) 0.68 NS NA
5/3/10
0.71 NS NA NS NA NS NA NS NA
9/20/10
0.63 NS NA
11/19/10
0.77 NS NA Semi-Annually
MW-3A
(Class III)
Field pH (S.U.) 6.5 - 8.5 NS NA
5/4/10
6.23
(6.24) NS NA NS NA NS NA NS NA
9/21/10
6.23 NS NA
11/22/10
6.23 NS NA Semi-Annually MW-3A
(Class III) Sulfate (mg/L) 3640 NS NA 5/4/10 3680 NS NA NS NA NS NA NS NA 9/21/10 3630 NS NA 11/22/10 3850 NS NA Semi-Annually
MW-3A
(Class III)
TDS (mg/L) 5805 NS NA
5/4/10
5860 NS NA NS NA NS NA NS NA
9/21/10
5470 NS NA
11/22/10
5330 NS NA Semi-Annually
MW-3A
(Class III)
Selenium (ug/L) 89 NS NA
5/4/10
81.4 NS NA NS NA NS NA NS NA
9/21/10
NS NS NA
11/22/10
94.8 NS NA Semi-Annually
MW-5
(Class II) Uranium (ug/L) 7.5 NS NA 4/26/10 0.39 NS NA NS NA NS NA NS NA NS NA NS NA 11/11/10 11.6 NS NA Semi-Annually
MW-12
(Class III) Selenium (ug/L) 25 NS NA 4/27/10 25.7 NS NA NS NA NS NA NS NA 9/20/10 31.9 NS NA 11/19/10 27.6 NS NA Semi-Annually
MW-18
(Class III)
Thallium (ug/l) 1.95 NS NA
5/4/10
3.73 NS NA NS NA NS NA NS NA
9/15/10
3.64 NS NA
11/18/10
3.57 NS NA Semi-Annually MW-18
(Class III) Sulfate (mg/L) 1938.9 NS NA 5/4/10 1950 NS NA NS NA NS NA NS NA 9/15/10 1930 NS NA 11/18/10 1910 NS NA Semi-Annually MW-18
(Class III) Field pH (S.U.) 6.25-8.5 NS NA 5/4/10 6.2 NS NA NS NA NS NA NS NA 9/15/10 7.15 NS NA 11/18/10 7.15 NS NA Semi-Annually
MW-18
(Class III)
TDS (mg/L) 3198.77 NS NA
5/4/10
3280 NS NA NS NA NS NA NS NA
9/15/10
3190 NS NA
11/18/10
3030 NS NA Semi-Annually
Ql Results Q2 Results Q3 Results
Monitoring
Well
(Water
Class)
Constituent
Exceeding GWCL
GWCL in
Current
GWDP
Ql
Sample
Date
Ql Result
Q2
Sample
Date
Q2
Result
May
Monthly
Sample
Date
May
Monthly
Result
June
Monthly
Sample
Date
June
Monthly
Result
July
Monthly
Sample
Date
July
Monthly
Result
August
Monthly
Sample
Date
August
Monthly
Result
Q3
Sample
Date
Q3
Result
October
Monthly
Sample
Date
October
Monthly
Result
Q4
Sample
Date
Q4
Result
December
Monthly
Sample
Date
December
Monthly
Result
Sample
Frequency
Required Semi-Annual Sampling Wells, continued
MW-19
(Class III) Field pH (S.U.) 6.78-8.5 NS NA 5/4/10 6.61
(6.66) NS NA NS NA NS NA NS NA 9/15/10 6.61 NS NA 11/18/10 6.61 NS NA Semi-Annually
MW-23
(Class III) Field pH (S.U.) 6.5 - 8.5 NS NA 4/22/10 6.18 NS NA NS NA NS NA NS NA 9/14/10 6.18 NS NA 11/22/10 6.18 NS NA Semi-Annually
MW-24
(Class III)
Cadmium (ug/L) 2.5 NS NA
5/6/10
4.28 NS NA NS NA NS NA NS NA
9/21/10
5.06 NS NA
11/17/10
3.22 NS NA Semi-Annually MW-24
(Class III) Thallium (ug/L) 1 NS NA 5/6/10 1.3 NS NA NS NA NS NA NS NA 9/21/10 1.57 NS NA 11/17/10 1.09 NS NA Semi-Annually MW-24
(Class III)
Field pH (S.U.) 6.5 - 8.5 NS NA
5/6/10 5.91
(5.78) NS NA NS NA NS NA NS NA
9/21/10
5.91 NS NA
11/17/10
5.91 NS NA Semi-Annually
MW-27
(Class III)
Nitrate -i- Nitrite (as N)
(mgA.) 5.6 NS NA
5/3/10
5.8 NS NA NS NA NS NA NS NA
9/14/10
5.9 NS NA
11/12/10
5.7 NS NA Semi-Annually
MW-27
(Class III)
Chloride (mg/L) 38 NS NA
5/3/10
42 NS NA NS NA NS NA NS NA
9/14/10
42 NS NA
11/12/10
45 NS NA Semi-Annually MW-27
(Class III) Sulfate (mg/L) 462 NS NA 5/3/10 469 NS NA NS NA NS NA NS NA 9/14/10 461 NS NA 11/12/10 452 NS NA Semi-Annually
MW-27
(Class III)
TDS (mg/L) 1075 NS NA
5/3/10
1160 NS NA NS NA NS NA NS NA
9/14/10
1060 NS NA
11/12/10
1110 NS NA Semi-Annually
MW-27
(Class III)
Gross Alpha minus Rn
& U (pCi/L) 2 NS NA
5/3/10
1.6 NS NA NS NA NS NA NS NA
9/14/10
NA NS NA
11/12/10
2.4 NS NA
MW-28
(Class III)
Chloride (mg/L) 105 NS NA 4/I9/I0 108 NS NA NS NA NS NA NS NA 9/14/10 11)6 NS NA 11/12/10 107 NS NA Semi-Annually MW-28
(Class III) Field pH (S.U.) 6.1 - 8.5 NS NA 4/I9/I0 5.67 NS NA NS NA NS NA NS NA 9/14/10 5.67 NS NA 11/12/10 5.67 NS NA Semi-Annually
MW-32
(Class III)
Gross Alpha minus Rn
& U (pCi/L) 3.33 NS NA 4/20/10 5.4 NS NA NS NA NS NA NS NA 9/13/10 2.9 NS NA 11/10/10 8.8 NS NA Semi-Annually MW-32
(Class III) Field pH (S.U.) 6.4 - 8.5 NS NA
4/20/10
6.03 NS NA NS NA NS NA NS NA
9/13/10
6.03 NS NA
11/10/10
6.03 NS NA Semi-Annually
Notes:
GWCL values are taken from January 20, 2010 version of GWDP.
NS = Not Required and Not Sampled
NR = Required and Not Reported
NA = Not Applicable
Exceedances are shown in yellow
Values in green are considered suspect. Data review indicated sample results are associated with elevated Method Blanks. Reanalysis of the samples has been requested.
0 Values shown in parentheses are results from resampling of the well during the same sample period. Wells were resampled due to a field or laboratory problem which is described in the report for that sampling period.