DRC-2010-003204 - 0901a0688018ae98

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May T2,2010
VIA PDF AND FEDERAL EXPRESS
Mr. Dane L. Finerfrock
Co-Executive Secretary
Utah Water Quality Board
State of Utah Department of Environmental Quality
168 North 1950 West
P.O. Box 144850
Salt Lake City, UT 84114-4850
Dear Mr. Finerfrock:
Re: Chloroform Contamination Investigation. Chloroform Concentrations Exceeding the
Groundwater Quality Standard in Monitor Well TW4-6. Submittal of a Revised Plan of
Action and Work Schedule. Revision in Response to DRC Letter of February 18, 2010.
Recent chloroform concentrations in monitor well TW4-6 at the White Mesa Mill (the *Mill")
have exceeded the 70 ugll State of Utah groundwater quality standard, requiring an adjustment to
the hydraulic containment program relating to the chloroform contamination plume at the Mill.
On December 31, 2009 Denison Mines (USA) Corp. ("Denison") submitted a plan of action and
work schedule to achieve hydraulic containment at TW4-6 as required by the Confirmatory
Action Letter dated November 9,2009.
On February ll,2010 Division of Radiation Control (*DRC") and Denison staff had a conference
call to discuss Denison's proposed plan of action and schedule, at which time Denison agreed to
make several modifications to the plan and schedule. The conclusions reached during that
conference call were confirmed in an email dated Februarv 11. 2010 from DRC Staff to Denison.
Enclosed please find:
a) a copy of the letter report dated December 28,2009 from Hydro Geo Chem, Inc., that was
previously submitted with Denison's December 31, 2009 plan and schedule; and
b) a letter report dated February 16,2010 from Hydro Geo Chem, Inc., that addresses certain
of the modifications to the plan and schedule discussed with DRC on February 11, 2010.
In accordance with the recommendations in Hydro Geo Chem's two letter reports, and the
discussions with DRC staff on February 11,2010, Denison proposes the following revised plan of
action and work schedule to achieve hydraulic containment at TW4-6:
1. On or before January 3I, 2009, Denison commenced pumping at TW4-4, which is
immediately upgradient of TW4-6, using similar pumping equipment and procedures as currently
utilized for the other chloroform pumping wells at the Mill site.
2. Denison will expand the chloroform capture zone and groundwater contour maps to
include groundwater head data at well MW-17 and piezometer P-5. These revised maps will b_e
contained in the quarterly chloroform monitoring reports, commencing with the report for the l"'
quarter of 2010.
3. Denison will install new chloroform monitoring well TW4-26 at the location indicated on
Figure 1 attached to Hydro Geo Chem's February 16,z}l}letter report. This well and all other
new monitoring well(s) will be permanent and constructed in accordance with UAC R317-6-
6.3(D(6) and shall comply with Part 1.F.6 of the Denison Ground Water Discharge Permit No.
UGW370004. The well will be installed and developed by August 1,2010. TW4-26 and any
other monitoring well(s) installed downgradient of TW4-6 will be sampled quarterly for the
analytical parameters listed in section 4 in Appendix A of the White Mesa Uranium Mill Ground
Water Monitoring Quality Assurance Plan.
4. Denison will aquifer test TW4-4, TW4-6 andTW4-26, on or before August I,2010,to
a) Calculatepermeabilitiesandhvdraulicconductivities:b) Calculate iocal groundwater velocities; andc) Determine an efficient pumping system at each pumping well location.
Such aquifer testing will be described in a report that will be submitted to the Executive Secretary
on or before Septernber 30,2010. Should the Executive Secretary require additional new monitor
well(s) be installed down gradient of TW4-6, an aquifer test to calculate items in a and b above
will be described in a report that will be submitted to the Executive Secretary within 60 calendar
days after well installation..
5. Analytical results for chloroform samples from TW4-4, TW4-6 and TW4-26 will be
reported in the Quarterly Chloroform Monitoring Reports that are filed with the Executive
Secretary.
6. After submittal of the 4th quarter, 2010 chloroform monitoring report, if the Executive
Secretary determines for any reason that pumping TW4-4 is not effectively reducing the
chloroform concentration in TW4-6 Denison will begin pumping TW4-6 within 30 days of
written notice from the Executive Secretary.
7. The pumping of TW4-4, or, if required under paragraph 6 or 7 above, both TW4-4 and
TW4-6, will continue until the chloroforrn concentration in TW4-6 has been reduced to below 70
ugl.
8. If, after review of at least two quarters of sample results from TW4-26 it is determined
that the chloroform concentration in TW4-26 exceeds 70 u!1, then Denison will install an
additional monitoring well, at a location agreed to by the Executive Secretary, within 60 days
DEN'SOJ)/I
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after the location has been agreed to by the Executive Secretary. If at least two quarters of sample
results for this additional well indicate a chloroform concentration in excess of 70 ugll in that
well, this process of adding an additional monitoring well will be repeated until such time as the
sample results for an added monitoring well are less than 70 ull chloroform.
If you have any questions or require any further information, please contact the undersigled.
Yours very truly,
Vice President, Regulatory Affairs and Counsel
Ron F. Hochstein
Harold R. Roberts
Jo Ann Tischler
David E. Turk
Stewart Smith
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HYDITO cEO CI"1I1M^ lNC,
Et t yirau u nt t n I Sri m r r t'l'rclniln6t
February 16,2010
David Frydenlund, Esq.
Denison lvline.s (USA) Colporarion
1050 17th Sfirer, Suire 950
Denver, Coloradc 80265
Dear Mr. Frydcnlund,
This is a follow-up to Hydro Oeo Chem, Inc's (HGC's) Dccember 28, 2009lener to Mr.
Steven Landau, Denison Mines, thal addrcssed the detection of chloroform at concentrations
exceeding 70 micrograms per Liter (pg/L) at perched well TW4-6 at the r#hite Mesa Uranium Mill
(the "sile"). As discussed in the Preliminary Con'ective Action Plan (PCAP) for the sire, should
concentrations at a downgradient well such as TW4-6 exceed ?0 pg&, a new downgradient well is to
beinstalled with tlrsconcunence of the Utah Departmenl of EnvironmentalQuality (UDEQ)" HGC
recommended an altentaiite that consisted of punrping TW4-4, the well located immediately
upgradient of TW4'6, and delaying the in$lallation of a new downgradienr wetrl to $ee, if the
upgradient pumping would reduce concentrations at TW4-6 below ?0 p g/L. Pumping of T'W4-6 was
also recommended if concentration.s at TW4-6 did not decrease as a result of pumping TW4-4.
Under the alternativs, a nelry well would be installed downgradient of TW4-6 slrould concentrations
al TW4-6 continue to increase during pumping of both wells.
As indicated in your Februriry 12,2010 e-mail, UDEQ requesrs the insrallation of a new
downgradient well before the impact of pumping on concentrarions at TW4-d can be deternrined by
monitoring. UDEQ also rquests that hydraulic tests be performed on the new wctl, and existing
wells TW4*4 and TW4-6, to allow calculation of the hydraulic conductivities, pcrched water porc.
velocilies, and efficient pumping schemes at each location.
The proposed location for the new well, designated TW4-25, is provided on Figure l, which
is a water level contour map based on December 2fs9 measwements. The water level contours
indicate that conditions south of TW4-6 are complicated by rhe prescnce of the southern wildtife
pond (to the south-soutbwest) and the persistently low water level ar TW4-14 {to the northeast}.
These features result in a change from a generally southerly hldraulic gradienr north of TW4{ to an
apparently more easterly gradient south of TW4-6. The proposed well is therefore located soutlr-
southeast of TW4-6, at about equal distances from TW4-14 (ro the northeasti and TSr4-23 (to the
west-norlhwest).
5l l\Ie.st \terrnore, Srritc l0l Tur.snn, ilriutna S5?05,1{t78 IS,,520.?93.1 5{t0 5?0.294. l55O-F u 8Q0,727 .55$7.1iil| Srcc
David F'rydenlund, l!sq.
February 16, 2010
Page2
HGC proposes to per{orm the hydraulic tests on fle new well, and exi$ting wells TW44 and
TW4-6, after installation, and developmenl of the new well, Testing procedurres will be the same as
described in HGC, 2005'.
Please feel free to contact rne if you have any questions or need adclitional inforrrration,
Attachment: Figure (l)
I HGC, 2005 Perehed Monitoring Well Inrtallation and Tesring at the White Mesa Uranium Mill, Aprit thr.ough
June 2005. Submitted to Intemational Uranium (USA) Corporation,
ll:\? I Smohvofcb lOlm I Jdt_ltrrte
ATTACHMBNT
ITIGURE
Kriged Decenrber 2009 Water l,evels Showing Extent of Chloroform > ?0 prg/L agctLocation of Proposed Well TW4-26, White Mesa Site
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VIA PDF AND FEDERAL EXPRESS
Mr. Dane L. Finerfrock
Co-Executive Secretary
Utah Water Quality Board
State of Utah Department of Environmental Quality
168 North 1950 West
P.O. Box 144850
Salt Lake city, UT 84114-4850
Dear Mr. Finerfrock:
Re: Chloroform Contamination Investigation. Chloroform Concentrations Exceeding the
Groundwater Quality Standard in Monitor Well TW4-6. Submittal of a Revised Plan of
Action and Work Schedule. @evision in Response to DRC
Letter of Februarv 18. 2010.
Recent chloroform concentrations in monitor well TW4-6 at the White Mesa Mill (the "Mill")
have exceeded the 70 ugll State ofUtah groundwater quality standard, requiring an adjustment to
the hydraulic containment program relating to the chloroform contamination plume at the Mill.
On December 31, 2009 Denison Mines (USA) Corp. ("Denison") submitted a plan of action and
work schedule to achieve hydraulic containment at TW4-6 as required by the Confirmatory
Action Letter dated November 9. 2009.
On February I l, 2010 Division of Radiation Control ('DRC") and Denison staff had a conference
call to discuss Denison's proposed plan of action and schedule, at which time Denison agreed to
make several modifications to the plan and schedule. The conclusions reached during that
conference call were confirmed in an email dated February I l. 2010 from DRC Staff to Denison.
Enclosed please find:
a) a copy of the letter report dated December 28,2009 from Hydro Geo Chem, Inc., that was
previously submitted with Denison's December 31,2009 plan and schedule; and
b) a letter report dated February 16,2010 from Hydro Geo Chenl Inc., that addresses certain
of the modifications to the plan and schedule discussed with DRC on February I l, 2010.
In accordance with the recommendations in Hydro Geo Chem's two letter reports, and the
discussions with DRC staff on February 11, 2010, Denison proposes the following revised plan of
action and work schedule to achieve hydraulic containment at TW4-6:
1. On or before January 31, 2009, Denison commenced pumping at TW44, which is
immediately upgradient of TW4-6, using similar pumping equipment and procedures as currently
utilized for the other chloroform pumping wells at the Mill site.
2. Denison will expand the chloroform capture zone and groundwater contour maps to
include groundwater head data at well MW-17 and piezometer P-5. These revised maps will be
contained in the quarterly chloroform monitoring reports, commencing with the report for the 1"
quarter of2010.
3. Denison will install new chloroform monitoring well TW4-26 at the location indicated on
Figure 1 attached to Hydro Geo Chem's February 16,2010 letter report. This well and all othernew monitorins well(s) will be permanent and constructed in accordance with UAC R3l7-6-
6.3(lX6) and shall comply with Part 1.F.6 of the Denison Ground Water Discharge Permit No.
UGW370004. The well will be installed and developed by August l, 2010. TW4-26 and any
other monitorine well(s) installed downsradient of TW4-6 will be sampled quarterly for the same
4
Appendix A of the White Mesa Uranium Mill Ground Water Monitoring Ouality Assurance Plan.
4. Denison will aquifer test TW4-4, TW4-6 and.TW4-26, on or before August 1, 2010, to
a) Calculatepermeabilities andhydraulic conductivities;b) Calculate local groundwater velocities; andc) Determine an efficient pumping system at each pumping well location.
Such aquifer testing will be described in a report that will be submitted to the Executive Secretary
onorbeforeSeptember30,20l0. ShouldtheExecutiveSecretaryreouireadditionalnewmonitor
well(s) be installed down gradient of TW4-6. an aquifer test to calculate items in a and b abovewill be described in a report that will be submitted to the Executive Secretarv within 60 calendar
days after well installation..
5. Analytical results for chloroform samples from TW4-4, TW4-6 and TW4-26 will be
reported in the Quarterly Chloroform Monitoring Reports that are filed with the Executive
Secretarv.
6.
th,e4s;?d-and3d
-qua*er-s+Zge
ieasAfter submittal
if th nes for
OEN'sOJ)JIMINES
6 Denison besin numnins TW4-(5 within 30 davs of writte.n notice frnm the Fxecrrtive
Secretarv.r
tffi
----@
mping wetts€t the Mitt site'
is'---M
eemmenei
previeus ls qurter prer thereto- If the ehloreferm eeneentratien in TW t-6 is detemdned net te
ing
site'
&.2-_ The pumping of TW4-4, or, if required under paragraph 6 or 7 above, both TW4-4 and
TW4-6, will continue until the chloroform concentration in TW4-6 has been reduced to below 70
uC/l.
9, enee ehloreferm eeneentretiens in TW1-6 heve been redueed te belew ?g ug/l; Denisen * - - @
++8-1f, after review of at least two quarters of sample results from TW4-26 it is determined
that the chloroform concentration in TW4-26 exceeds 70 ug/|, then Denison will install an
additional monitoring well, at a location agreed to by the Executive Secretary, within 60 days
after the location has been agreed to by the Executive Secretary. If at least two quarters of sample
results for this additional well indicate a chloroform concentration in excess of 70 ugll in that
well, this process of adding an additional monitoring well will be repeated until such time as the
sample results for an added monitoring well are less than 70 ug/ chloroform.
If you have any questions or require any firther information, please contact the undersigned.
Yours very truly,
DuxrsoN Mnns (USA) Conr.
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Vicc Prpridml Rc&Lttry AfrLirs aud Couneel
Ron F. Hochctoin
Harotd R" Robcrts
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