DRC-2012-002341 - 0901a068803230e4

State of Utah
GARY R HERBERT
Governor
GREG BELL
Lieutenant Governor
Department of
Environmental Quality
Amanda Smith
Executive Director
DIVISION OF RADL\TION CONTROL
Rusty Lundberg
Director
DRC-2012-002341
TO
FROM
DATE
SUBJECT
MEMORANDUM
Phil Goble
Dean Henderson j^l^/^
November 6,2012
Review of the Redevelopment of Existing Perched Momtonng Wells at the White
Mesa Mill, submitted on September 30,2011 by Denison Mines (USA) Corp for
the White Mesa Uranium Mill, near Blanding, Utah
This IS a review of Denison Mines (USA) Corp's [company changed name to Energy Fuels
Resources (USA), Inc. ("EFR")] report on Redevelopment of Existing Perched Monitoring Wells
at the White Mesa Mill ("Report") EFR requested, beginning in February 2010, that the Utah
Division of Radiation Control ("DRC") agree to a vanance from the groundwater Quality
Assurance Plan ("QAP") requirements that turbidity m momtonng wells should be 5
nephelometnc turbidity units ("NTU") or less and must equilibrate to within 10 % RPD. The
Report was prepared m response to the requirement in DRC's letter of June 1, 2010, which stated.
"Before DRC can consider approval of any variance regarding turbidity in monitoring wells,
DUSA has to provide convincing evidence that all monitoring wells at the Mill have been
developed properly and all commonly [used] well development methods were attempted and
exhausted "
REVIEW
Monitor Well Development Method
EFR used the surging and bailing followed by overpumping methods for monitor well
development Surging and bailing followed by overpumping is consistent with and acceptable
well development techmques in the U S Environmental Protection Agency (EPA) guidance,
guidance provided in Dnscoll (1986) and Aller et al, (1991), and EPA (1992,1994 and 2001),
and Yeskis and Zavala In addition, based on the DRC staff field expenence with developing
momtor wells, DRC staff agrees that surging and bailing followed by overpumping is reasonable
and recommends that the DRC accepts this well development method
195 Nortli 1950 West • Salt Lake City, UT
Mailing Address P O Box 144850 • Salt Lake City, UT 84114-4850
Telephone [phone] • Fax (801) 533^097 -TDD [phone]
www deq Utah gov
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Page 2
Monitor Well^ Development Activities
EFR developed a total of 54 MW-, TWN- and TW4-senes momtor wells Water volumes were
removed using surging and bailing followed by overpumping method ranged from 3 to 7 well
casing volumes for wells that had a water column 12 feet or less, and for wells that had greater
than a 12 foot water column, 7 to 13 well casing volumes were removed After development
actrvities were completed only 8 of the 54 momtor wells had turbidity measurements of > 5 NTU
After the review ofthe infonnation provided in the Report it appears that because 1) shale and
clay interbeds in both the Burro Canyon Formation and Dakota Sandstone, that host the perched
water monitored by the wells, are likely to mobilize dunng purging Kaolimte, reported to be
present as a cementing matenal in both the Dakota and Burro Canyon, may likely be a continuing
source of turbidity in perched wells, and 2) the friable sands and conglomeratic matenals reported
within the Burro Canyon may also contnbute to the turbidity in perched wells therefore, it is
difficult to develop monitor wells installed in the Dakota and Burro Canyon formations to a 5
NTU standard.
It appears that the level of effort to develop these momtor wells under the descnbed geologic and
hydrogeologic conditions was reasonable and acceptable
Effect of Turbidity on Monitoring Parameters
The QAP requires water to be analyzed for gross alpha and heavy metals to be filtered in the field
using a 0 45 micon filter therefore turbid water > 5 NTU will not affect analysis.
DRC staff sent emails to Amencan West Analytical Laboratones ("AWAL") located in Salt Lake
City, Utah and LionviUe Laboratory ("LL") located in Exton, Pennsylvania to ask if turbid water
samples > 5 NTU .effect analytical results for the remainder ofthe other momtonng parameters m
the QAP ammoma, nitrate, VOCs, pH, TDS, fluonde, chlonde, sulfate, carbonate, bicarbonate,
sodium, potassium, magnesium, calcium, and total amons and cations AWAL responded " /
don't think turbidity from clay and silt would skew the data much if at all The colorimetric tests
(Cl, S04, NOS) measure the amount of light blocked Turbidity can block light and create a false
signal but we are required to run samples before and after adding reagents and to subtract the
false signal from the turbidity (before reagents) from the true signal " And LL responded
" wet chem manager and turbidity should not be a big problem For your samples we usually
end up filtering or diluting some due to the high salt content It should be OK ".
Based on the above information turbid samples > 5 NTU should not affect analysis for the
momtonng parameters required in the QAP.
Turbidity as a Drinking Water Standard
It states in the Utah Momtonng and Water Quality Dnnking Water Standards R309-200-
4(5)(c)(ii) The limit for turbidity in drinking water from ground water sources not under the direct
influence of surface sources is 5 0 NTU based on an average for two consecutive days pursuant to
R309-205-8(3)
Page 3
The groimdwater purged and sampled from the MW-, TWN- and TW4-senes momtonng wells at
the Mill facility is not used for dnnking water Therefore to achieve a turbidity standard of 5
NTU IS not really necessary for well development and as a compliance parameter for groundwater
sampling
EFR Three Recommendations
Based on the results of the redevelopment, the following recommendations are made in the
Report After each EFR recommendation DRC will have a wntten response
1. EFR Recommendation* Abandon MW-20 This is appropriate because as a result of
damage due to disturbance during redevelopment, the well is no longer useful as a
perched monitoring well The well is no longer a compliance monitoring well and
abandonment of the well will not result in the loss of compliance information
DRC Response Monitor well MW-20 will still provide valuable groundwater elevation
and water quality data Therefore, DRC staff recommends that monitor well MW-20
remain as a general momtonng well
2 EFR Recommendation Remove turbidity as a stabilization parameter from the approved
QAP This IS appropriate because turbidity in the MW-, TWN- and TW4-series wells is
dependent on the nature of the formation hosting perched water at the site As
demonstrated by the redevelopment effort, turbidity cannot be improved, and may continue
to deteriorate as a result of redevelopment
DRC Response In the cunently approved EFR QAP (Rev. 7 2) Attachment 2-3, approved
on June7, 2012, EFR now has three purging strategies that will be used to remove stagnant
water from the casing dunng groundwater sampling at the Mill The three strategies are as
follows*
1. Purging three well casing volumes with a single measurement of field parameters
2. Purging two casing volumes with stable field parameters (within 10% RPD)
3 Purging a well to dryness and stability of a limited list of field parameters after recovery
The groundwater in the well should recover to withm at least 90% of the measured
groundwater static surface before sampling If after 2 hours, the well has not recovered to
90% the well will be sampled as soon as sufficient water for the fiill analj^ical suite is
available
Because of the recent changes m the QAP, DRC staff believes that EFR now has options
to deal with wells with potential parameter stability issues, therefore, DRC staff believes
no change should be made to the QAP.
3 EFR Recommendation* Based on consideration of all well information available to date,
Denison has determined that low-flow/micro-purging will not provide any benefit in
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sampling any of the wells Denison chooses to withdraw the draft of the QAP submitted on
June 4, 2010 proposing these techniques
DRC Response DRC accepts the EFR withdrawal ofthe draft ofthe QAP (Rev 7.0)
submitted on June 4, 2010 proposing low-flow/micro-purging techniques for monitor well
sampling
Page 5
References
Aller, Linda, Truman W. Bennett, Glen Hackett, and Rebecca J Petty 1991 Handbook of
Suggested Practices for the Design and Installation of Ground Water Momtonng Wells
EPA160014-891034. March 1991.
EPA Environmental Response Team 1994. SOP 2044 Rev 00 October 3,1994
EPA Environmental Response Team 2001. SOP 2044 Rev 01 October 23, 2001
Yeskis, Douglas and Bernard Zavala 2002 Ground Water Sampling. Guidelines for
Superfimd and RCRA Project Managers. Ground Water Forum Issue Paper. Office of Solid
Waste and Emergency Response EPA 542-S-02-001 May 2002
U S Environmental Protection Agency (EPA) 1992. RCRA Ground-Water Momtonng Draft
Techmcal Guidance Office of Solid Waste, U S. Environmental Protection Agency 401
M Street, S W, Washington, D C. 20460 November 1992
Utah Environmental Quality Dnnking water, R309-200-5 Turbidity