DRC-2011-006597 - 0901a068802450e7

DENISO
MINES
Denison Mines (USA) Corp.
1050 17th Street, Suite 950
Denver, CO 80265
USA
Tel: [phone]
Fax:[phone]
www.denisonmines.com
i
June 17, 2011
VIA E-MAIL AND OVERNIGHT DELIVERY
Mr. Rusty Lundberg
Utah Department of Environmental Quality
195 North 1950 West
P.O. Box 144850
Salt Lake City, UT 84114-4850
Re: State of Utah Groundwater Discharge Permit ("GWDP") No. UGW370004
Notice of Violation and Groundwater Corrective Action Order, Docket No. UGW20-01 - Request for
Additional Information
Dear Mr. Lundberg:
This letter provides Denison Mines (USA) Corp's ("Denison's") response to the Utah Division of Radiation
Control's ("DRC's") May 26, 2011 Request for Additional Information ("RFI") received June 2, 2011 and to
discussion during DRC's May 17, 2011 conference call with Denison.
Enclosed with this letter as Attachment 1 is a copy of a letter report from Hydro Geo Chem, Inc., dated June
17, 2011 (the "Hydro Geo Chem Report"), which addresses certain matters raised in the RFI.
We have provided, below, specific responses to each request in the RFI. The sections and numbering of the
remainder of this letter follow DRC's May 26, 2011 letter. Each DRC request is shown in italics, below,
followed by Denison's response.
DRC Comments and Responses
DRC Comment:
However, in our conference call on May 17, 2011 we agreed that DUSA would complete one ofthe following by
June 17, 2011:
1. Submit a report for Executive Secretary approval to justify why chloroform isoconcentration data alone is
sufficient to define the full physical extent ofthe contamination plume down gradient of well TW4-4 and TW4-6
or,
2. Submit for the Executive Secretary approval a plan of action and work schedule to complete the installation
of one or more wells in locations hydraulically down gradient of wells TW4-4 and TW4-6 to demonstrate the
plume is bound and to assure that the plume is hydraulically being captured in this vicinity. In conjunction with
the existing wells, these new well(s) must show on a map:
The 70 ug/l chloroform isoconcentration line remains hydraulically up gradient to the
N:\Chloroform\New Cfm well SE\06.17.11 Final to DRC\06 17 11 Response to DEQ 05 26 11 chloroform RFI_Final.doc
Letter to Mr. Rusty Lundberg
Chloroform RFI Response
June 17, 2011
Page 2
new well(s) and.
Groundwater contour lines must show the new well(s) are hydraulically down gradient to TW4-4 and
TW4-6.
Denison Response: The Hydro Geo Chem Letter, enclosed as Attachment 1 to this letter, recommends an
approach for the installation of one or more monitoring wells hydraulically down gradient of wells TW4-4 and
TW4-6 to demonstrate that the chloroform plume is bounded and being hydraulically captured in the vicinity.
Attached as Appendix A to this letter is Denison's plan of action and work schedule (the "Plan") to implement
the recommendations set out in the Hydro Geo Chem Report.
As described in the Hydro Geo Chem Report, Denison believes that controlling the piume at TW4-6 does not
require the demonstration of hydraulic containment at TW4-6, and that continued decreases in chloroform
concentration at TW4-6 would demonstrate that pumping is effective at TW4-4. However, in order to
demonstrate continued concentration decreases, and that concentration data alone are sufficient to define the
full physical extent of the contamination plume down gradient of wells TW4-4 and TW4-6, as required in item
1, above, it would likely take more time than UDEQ has indicated would be acceptable. Therefore, the Plan is
being submitted in response to item 2 above.
DRC Comment:
1. The 4th quarter 2010 water levels and estimated capture zones map does not show the locations of
wells TW4-23, TW4-24, and TW4-25. Please assure that in the future all maps submitted will show all well
locations, beginning with the 2nd Quarter, 2011 Chloroform Monitoring Report, due on September 1,2011.
Denison Response: The 4th quarter 2010 water levels and estimated capture zones map does show the
locations of wells TW4-23, TW4-24, and TW4-25, however, these wells are not labeled on the map. A revised
version of this map is provided as Figure 2 in Attachment 1 to this letter. Denison will use this map in future
chloroform reports beginning with the 2"^ Quarter 2011 Chloroform Monitoring Report.
DRC Comment:
2. In Appendix G in the 1st, 2nd, 3rd, and 4th quarter 2010 chloroform monitoring reports DUSA has
reported wells with incorrect measuring point elevations for depth to groundwater measurements. Below is a
table summarizing the wells with erroneous measuring point elevations. Please make these corrections.
Denison Response: Thank you for identifying the errors in the well measuring point elevations. Denison will
make all the corrections as indicated in the table of well measuring point elevations, included with DRC's
comment, except for measuring point elevation for TW4-23. The Well Construction Schematic drawing as
provided in the March 17, 2010 As-Built Report from Hydro Geo Chem is incorrect. A revised drawing
showing the correct values for the ground level and measuring point level has been provided in Attachment 2.
The correct value for the measurement point elevation, as shown on the revised drawing, is 5607.37 feet
amsl.
Denison will correct these values, as indicated in the comment and the revised TW4-23 As-Built, in future
quarterly chloroform reports beginning with the 2"^^ Quarter of 2011 Chloroform Monitoring Report. The
correct values, including the proper elevation for TW4-23, were used in the groundwater contour maps and
capture zone maps for the 2010 quarterly reports referred to above, and in the sections of the report text
based on these maps. The incorrect values have appeared only in the Appendix G tables of Water Level and
Data over Time in those reports. (The Appendix H plots do not use these values and are correct as
published).
DENISO
MINES
Letter to Mr. Rusty Lundberg
Chloroform RFI Response
June 17, 2011
Page 3
If DRC requires that these corrections be made in any previous reports, Denison would like an opportunity to
discuss with DRC how and when this is to be accomplished, since some of the incorrect elevation values
have been used in Depth to Groundwater/Elevation table entries as early as 1999.
DRC Comment:
3. In Appendix G in the 1st, 2nd, 3rd, and 4th quarter 2010 chloroform monitoring reports, DUSA has
reported wells with incorrect well depths. Below is a table summarizing the wells with incorrect [depths
compared] to the corresponding correct well depth. Please make these corrections.
Denison Response: Thank you for identifying the errors in the well depths. Denison has reviewed the
spreadsheets used to generate the Appendix G tables of Water Level and Data over Time, and the Appendix
F Hydrographs of Groundwater Elevations over Time and determined an error in the spreadsheet resulted in
duplicating an incorrect value into the same field in eight of the tables.
Denison will make all the corrections as indicated in the table of well depths included with DRC's comment,
except for the well depths for MW-32 and TW4-10. Mill sampling personnel sounded all of the Mill's
groundwater, chloroform, and nitrate wells, via use of measuring tape, in February 2011. The values for the
well depths for MW-32 and TW4-10, based on actual tape measurement, have been adjusted to 130.6 feet
bgs and 111 feet bgs respectively. For future chloroform reports, Denison will use the corrected values in the
table accompanying DRC's comment, and the two adjusted values for MW-32 and TW4-10 from the tape
measurement.
Denison will correct these values in future quarterly chloroform reports beginning with the 2"^^ Quarter of 2011
Chloroform Monitoring Report. The correct values have been used consistently in the groundwater contour
maps and capture zone maps, and in the sections of the report text based on these maps for the 2010
quarterly reports referred to above. The adjusted values for MW-32 and TW4-10 have been used since 1^*
Quarter 2011. The incorrect values have appeared only in the Appendix G tables of Water Level and Data
over Time for those reports. (The Appendix H plots do not use these values and are correct as published).
If DRC requires that these corrections be made in any previous reports, Denison would like an opportunity to
discuss with DRC how and when this is to be accomplished, since the incorrect elevation values have been
used in Depth to Groundwater/Elevation table entries as early as 2002.
Please contact me if you have any questions or require any further information.
Yours very truly,
DENISON MINES (USA) CORP.
'(Jo Ann Tischler
Director, Compliance and Permitting
cc: David C. Frydenlund
Harold R. Roberts
David E. Turk
DENISO
MINES
'-^ttertoM
Weinel
Attack ^iTients
Letter to Mr. Rusty Lundberg
Chloroform RFI Response
June 17, 2011
Page 5
APPENDIXA
WHITE MESA MILL
Notice of Violation and Groundwater Corrective Action Order, Docket No. UGM20-01
PLAN OF ACTION
And
WORK SCHEDULE
For the Installation of One or More Monitoring Wells Downgradient of
TW4-4 and TW4-6
Denison Mines (USA) Corp
1050 l/^ Street, Suite 950
Denver, CO 80265
June 17, 2011
DENISO
MINES
Letter to Mr. Rusty Lundberg
Chloroform RFI Response
June 17, 2011
Page 6
Reference is made to the letter from the State of Utah Division of Radiation Control ("DRC") dated May 26,
2011, requesting additional information relating to the chloroform groundwater investigation at the Denison
Mines (USA) Corp. ("Denison") White Mesa Mill (the "Mill"), pursuant to Notice of Violation and Groundwater
Corrective Action Order, Docket No. UGW20-01.
In accordance with the recommendations in Hydro Geo Chem Inc.'s letter report dated June 17, 2011 (the
"Hydro Geo Chem Report"), Denison proposes the following plan of action and work schedule the ('Plan") to
complete the installation of one or more wells in locations hydraulically downgradient of existing chloroform
monitoring wells TW4-4 and TW4-6 to demonstrate that the chloroform plume is bounded and to assure that the
plume is under hydraulic capture in this vicinity:
1. Work Plan
1.1. Installation of TW4-27
A single new well (TW4-27) will be installed south of TW4-14 and east of TW4-6 and TW4-26 at the location
provided on Figure 6 of the Hydro Geo Chem Report. A single well at this location is considered adequate to
ensure that chloroform does not move undetected in an unanticipated easterly direction toward the eastern
property boundary. TW4-27 will be a monitoring well and will not be a pumping well.
The proposed location for TW4-27 would
a) extend the current network of easternmost monitoring wells to the south,
b) provide additional data to indicate whether the water level at TW4-14 is anomalous, and
c) provide additional data to address UDEQ's concerns about potential eastward migration of chloroform.
TW4-27 will be permanent and constructed in accordance with UAC R317-6-6.3(l)(6) and will comply with Part
1.F.6 of the Denison Ground Water Discharge Permit No. UGW370004. TW4-27 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.
1.1.1. Aquifer Testing of TW4-27
Provided there is sufficient saturated thickness, Denison will perform a hydraulic test at TW4-27 to:
a) Calculate permeabilities and hydraulic conductivities; and
b) Calculate local groundwater velocities.
Such aquifer testing will be described in a report (the "Hydrogeologic Report") that will be submitted to the
Executive Secretary.
112. Reporting
Analytical results for chloroform samples from TW4-27 and water levels will be reported in the Quarterly
Chloroform Monitoring Reports that are filed with the Executive Secretary of the State of Utah Radiation Control
Board (the "Executive Secretary").
DENISO
MINES
Letter to Mr. Rusty Lundberg
Chloroform RFI Response
June 17, 2011
Page 7
Denison will expand the chloroform capture zone and groundwater contour maps in those reports to include
sample results and groundwater head data at TW4-17.
1.2. Collection of Additional Water Level and Chloroform Data to Determine if TW4-27 Satisfies the
Stipulated Criteria
Water level and chloroform concentration data collected from the existing wells, and upon completion from
TW4-27, will be used to determine if:
a) the 70 pg/l chloroform isoconcentration line remains hydraulically upgradient of TW4-27; and
b) groundwater contour lines show that TW4-27 is hydraulically downgradient of TW4-4 and TW4-6.
1.3. Possible Abandonment of TW4-14
If water level data from TW4-27 indicate that the water level at TW4-14 is anomalous, TW4-14 will be
abandoned, with the approval of the Executive Secretary. The water level at TW4-14 will be considered
anomalous if the water level at TW4-27 is comparable to the water level at TW4-6.
1.4. Installation of Additional WelKs) if Necessarv
It may take some time for the hydraulic system to adjust to the addition of TW4-27. However, if after two
quarters of data, the criteria set out in paragraph 1.2 above are not satisfied, then Denison will propose a plan
and schedule at that time for the location of one or more additional wells, based on the information gained from
monitoring TW4-27.
2. Schedule
Denison proposes that the foregoing Plan be performed in accordance with the following schedule:
a) TW4-27 will be installed within 30 days after receipt of Executive Secretary approval of this Plan. An
as-built report, along with the Hydrogeologic Report, will be submitted to the Executive Secretary
within 60 days after the date of such approval.
b) Quarterly water level measurements and sampling will commence during the next regularly scheduled
chloroform sampling campaign after installation of the well. A determination of whether or not the
criteria specified in paragraph 1.2 above have been satisfied with the addition of TW4-27 will be made
after receipt of two quarters of water level and chloroform data. A decision whether or not to abandon
TW4-14 will also be made by Denison and the Executive Secretary at that time.
c) If it is determined that the criteria specified in paragraph 1.2 above have not been satisfied with the
addition of TW4-27, then Denison will submit within 30 days after submittal of the Quarterly Chloroform
Monitoring Report that contains the second of the two quarters of data referred to above, a plan and
schedule for installation of one or more additional chloroform monitoring wells.
DENISO
MINES
Letter to Mr. Rusty Lundberg
Chloroform RFI Response
June 17, 2011
Page 8
ATTACHMENT 1
DENISO
MINES
HYDRO GEO CHEM, INC.
Environmental Science & Technology
June 17,2011
David Frydenlund, Esq.
Denison Mines (USA) Corp.
1050 17th Street, Suite 950
Denver, Colorado 80265
Dear Mr. Frydenlund,
This letter provides a recommended approach in response to the Utah Department ofEnvironmental
Quality's (UDEQ's) concems regarding the southem tip of the perched zone chloroform plume at
Denison Mines (USA) Corp.'s (Denison's) White Mesa Uranium Mill (the site).
In a Tuesday, May 11 conference call with Denison and in a letter dated May 26, 2011, UDEQ
expressed concems over the adequacy of perched monitoring wells TW4-4, TW4-6, TW4-14, and
TW4-26 to define the chloroform distribution and hydraulic gradients in the vicinity of these wells,
and to establish whether or not chloroform in the vicinity of TW4-6 will be captured by pumping
TW4-4. Figure 1 is a map showing well locations and the boundaries of the chloroform plume based
on first quarter, 2010 and first quarter, 2011 chloroform data. Note that the southem portion of the
chloroform plume has been shrinking.
UDEQ believes that at least one additional perched monitoring well downgradient of TW4-4 and
TW4-6 is needed. In its May 26,2011 letter, UDEQ requested that Denison submit to the Executive
Secretary of the State of Utah Radiation Control Board (the Executive Secretary) for approval a plan
of action and work schedule to complete the installation of one or more wells in locations
hydraulically downgradient of wells TW4-4 and TW4-6 to demonstrate the plume is bounded and to
assure that the plume is hydraulically being captured in this vicinity. The letter also states that, in
conjunction with the existing wells, these new well(s) must show on a map:
• The 70 |jg/l chloroform isoconcentration line remains hydraulically upgradient to the new
well(s); and
• Groundwater contour lines must show the new well(s) are hydraulically downgradient to
TW4-4 and TW4-6.
51 West Wetmore, Suite 101 Tucson, Arizona 85705-1678 l"^-*' 520.293.1500 520.293.i550-Fax [phone]-Toll Free
David Frydenlund, Esq.
June 17,2011
Page 2
As described in more detail below and as explained in our telephone conference, I believe that the
existing wells adequately bound the chloroform plume and that additional wells are not necessary.
However, given UDEQ's request that one or more additional wells be installed, I propose that one
additional non-pumping chloroform monitoring well be installed at this time and that the water level
and chloroform concentration data from that well be used to determine if the criteria referred to
above are satisfied. If after the receipt of at least two quarters of data, Denison cannot demonstrate
that the criteria stated above have been satisfied, Denison will at that time be in a position to propose
one or more additional wells, based on a review of the data generated from TW4-27.
Overview
Perched monitoring wells TW4-4 and TW4-6 were installed in 2000 to monitor chloroform
concentrations in the downgradient portion of the plume. Concentrations at TW4-4, located
immediately upgradient (north) of TW4-6, have exceeded 70 |ig/L since the fu'st quarter of 2001 and
have remained above 1000 |ig/L. Chloroform concentrations at TW4-6 ranged from non-detect to a
maximum of 52 pg/L between 2000 and the fourth quarter of 2008. From the first quarter of 2009
through the fourth quarter of 2010 concentrations at TW4-6 exceeded 70 pg/L. Concentrations
reached a maximum of 1000 [ig/L in the first quarter of 2010 then began dropping. The
concentration at TW4-6 as of the first quarter of 2011 is again below 70 |ig/L. The concentration at
perched well TW4-26, installed at a location presumably downgradient (south) of TW4-6 in May,
2010, was initially 13 |ig/L and has dropped to 2 |ig/L. Concentrations at TW4-14 and TW4-23,
located east and west, respectively, of TW4-6, have been non-detect since installation in 2002 and
2007, respectively.
Because of the relatively high chloroform concentrations at TW4-4, and the increasing
concentrations at TW4-6, pumping of TW4-4 was initiated during the first quarter of 2010 to attempt
to reduce or reverse the increase in chloroform at TW4-6. Pumping at TW4-4 is more practical than
pumping at TW4-6 because the permeability of the perched zone at TW4-6 and TW4-26 is two
orders of magnitude lower than at TW4-4 (Hydro Geo Chem, 2010. Hydraulic Testing ofTW4-4,
TW4-6, and TW4-26, White Mesa Uranium Mill, July 2010). The estimated sustainable pumping
rates at TW4-6 and TW4-26 are less than 0.1 gallons per minute (gpm) whereas the estimated
sustainable pumping rate at TW4-4 is 4 gpm. Furthermore, pumping at TW4-6 would act to draw the
higher concentrations detected at TW4-4 downgradient to TW4-6.
Since initiation of pumping at TW4-4 in the first quarter of 2010, chloroform concentrations at TW4-
6 have decreased from 1000 |ig/L to 47 jig/L. Since installation in the second quarter of 2010,
concentrations at TW4-26 have decreased from 13 |ig/L to 2 ng/L. Water levels at TW4-6 have not
measurably decreased during this time period, making it difficult to assess whether it is within
hydraulic capture of TW4-4. The low permeability of the perched zone at TW4-6 and the decrease in
permeability between TW4-4 and TW4-6 makes slow development of hydraulic capture likely.
However, it is not necessary to establish hydraulic capture at TW4-6 to reduce concentrations at
TW4-6. It is sufficient only to reduce or cut off the source of chloroform to TW4-6 which is the
apparent result of pumping TW4-4 based on the data collected to date.
H:\718(X)0\lw27prop\tw27prop_rev3.doc
David Frydenlund, Esq.
June 17,2011
Page 3
With regard to the water levels in the vicinity of TW4-4, there has been a consistently low water
level at TW4-14 (located east of TW4-4) since installation in 2002. This low water level dominates
water level contours in the vicinity of TW4-4, TW4-6, and TW4-26. As of the first quarter of 2011,
the water level in TW4-14 was 12 feet lower than the level in TW4-6, and 19 feet lower than the
level in TW4-4 (even though TW4-4 is pumping). Similarly, in the fourth quarter of 2010, the water
level in TW4-14 was lower than in TW4-6 and TW4-4 by 13 feet and 9 feet, respectively. Figures 2
and 3 are kriged site-wide water level contour and estimated capture zone maps for the first quarter
of 2011 and the fourth quarter of 2010. These figures are identical to those submitted with their
respective Quarterly Chloroform Monitoring Reports except that TW4-6, TW4-14, and TW4-26 are
speciflcally labeled. Both figures, show closed contours surrounding TW4-14 suggesting that TW4-
14 is downgradient of TW4-4, TW4-6, and TW4-26. This is illustrated in the attached Figure 4
which is a detail map of the plume area showing perched water level contours and flow directions for
the first quarter of 2011. The water level at TW4-14 seems anomalous because if this well were
indeed downgradient of TW4-4, chloroform would be expected to migrate from TW4-4 to TW4-14
and not to TW4-6 and TW4-26 as has been demonstrated. If the water level data are kriged without
the water level at TW4-14, the water level contours indicate a perched hydraulic gradient to the
south-southwest, in a direction ranging from sub-parallel to away from the eastern property
boundary, as shown in Figure 5.
The water level data presented in Figures 4 and 5 indicate that regardless of whether the water level
at TW4-14 is considered anomalous, the likelihood that chloroform could move undetected toward
the eastem property boundary is minimal. The historical chloroform data indicate that the direction
of perched water flow is to the south or south-southwest from TW4-4 towards TW4-6 and TW4-26,
and not to the southeast toward TW4-14.
For these reasons, I believe that the existing monitoring well network adequately bounds the
chloroform plume and that additional wells are not necessary to the southeast of TW4-4 and TW4-6.
At the present time, the data from existing wells in this area seem adequate, especially considering
the shrinkage of the chloroform plume that has occurred since TW4-4 pumping began. However, I
realize that UDEQ disagrees with my position on this, and have therefore set out my
recommendations below for the installation of one (or more) additional monitoring wells.
Recommendations
In order to address UDEQ's concems, I recommend the following:
1. Installation ofTW4-27
One new well (TW4-27) will be installed south of TW4-14 and east of TW4-6 and TW4-26 (Figure
6). One well at this location is considered adequate to ensure that chloroform does not move
undetected in an unanticipated easterly direction toward the eastem property boundary. TW4-27 will
be a monitoring well and will not be a pumping well.
H:\718000\tw27prop\tw27prop_rev3.doc
David Frydenlund, Esq.
June 17,2011
Page 4
The proposed location for TW4-27 will
a) extend the current network of eastemmost monitoring wells to the south,
b) provide additional data to indicate whether the water level at TW4-14 is anomalous, and
c) provide additional data to address UDEQ's concerns about potential eastward migration of
chloroform.
2. Collection of Additional Water Level and Chloroform Data
Water level and chloroform concentration data collected from the existing wells, and upon
completion from TW4-27, will be used to determine if the addition of TW4-27 demonstrates that:
d) the 70 )ig/l chloroform isoconcentration line remains hydraulically upgradient of TW4-27;
and
e) groundwater elevations show that TW4-27 is hydraulically downgradient of TW4-4 and
TW4-6.
3. Possible Abandonment of TW4-14
Ifthe water level data from TW4-27 indicate that the water level at TW4-14 is anomalous, TW4-14
should be abandoned. The water level at TW4-14 will be considered anomalous if the water level at
TW4-27 is comparable to the water level at TW4-6. One the other hand, if the water level at TW4-27
is comparable to the water level at TW4-14 or if TW4-27 is dry, the water level at TW4-14 will not
be considered anomalous.
4. Installation of Additional WelKs) if Necessarv
It may take some time for the hydraulic system to adjust to the addition of TW4-27. However, if after
at least two quarters of data, the criteria set out in paragraph 2 above are not satisfied, then, Denison
should be in a position to propose a plan and schedule at that time for the location of one or more
additional wells, based on the information gained from monitoring TW4-27.
Please feel free to contact me if you have any questions or comments.
Sincerely,
Stewart J. Smith
Associate Hydrogeologist
Attachments (6)
H:\718000\tw27prop\tw27prop_rev3.doc
ATTACHMENTS
FIGURES
1 Site Plan and Perched Well Location Map Showing Q1, 2011 and Q1, 2010 Chloroform
Plumes as Defined by 70 ug/L Boundaries
2 Kriged 1"' Quarter, 2011 Water Levels and Estimated Capture Zones, White Mesa Site
3 Kriged 1"' Quarter, 2010 Water Levels and Estimated Capture Zones, White Mesa Site
4 Kriged 1'' Quarter, 2011 Water Level Detail Map Showing Estimated Flow Directions
and Ql, 2010 and Ql, 2011 Chloroform Plume Boundaries
5 Kriged 1Quarter, 2011 Water Level Detail Map Generated Excluding TW4-14 and
Showing Estimated Flow Directions and Ql, 2010 and Ql, 2011 Chloroform Plume
Boundaries.
6 Proposed Location of TW4-27 Showing Kriged Q1, 2011 Water Levels and Q1, 2011 and
Ql, 2010 Chlorofonn Plume Boundaries (Detail Map)
FIGURES
MW-20
TW4-19
o
PIEZ-1 e
TWN-1
o
TW4-26
MW-34
SCALE IN FEET
EXPLANATION
perched monitoring well
temporary perched monitoring well
perched piezometer
temporary perched nitrate
monitoring well
temporary perched monitoring well
installed May, 2010
perched monitoring well installed
August/September, 2010
^ ^ Ql, 2011 70 ug/L chloroform plume boundary
( I Q1, 2010 70 ug/L chloroform plume boundary
HYDRO
GEO
CHEM, INC.
SITE PLAN AND PERCHED WELL LOCATION MAP
SHOWING 01, 2011 AND Ql, 2010 CHLOROFORM PLUMES
AS DEFINED BY 70 ug/L BOUNDARIES
WHITE MESA SITE
APPROVED
SJS
REFERENCE
H :/718000/tw27prop/chl_10_11 .srf 1
PROPERTY
BOUNDARY
MW-22
• 5450
O5555
PIEZ-1
© 5593
TWN-4
O5604
TW4-26
^5537
MW-34
•<>-5492
SCALE IN FEET
EXPLANATION
perched monitoring well showing
elevation in feet amsl
temporary perched monitoring well
showing elevation in feet amsl
perched piezometer showing
elevation in feet amsl
temporary perched nitrate monitoring well
showing elevation in feet amsl
temporary perched monitoring well installed
May, 2010 showing elevation in feet amsl
perched monitoring well installed
August/September, 2010
showing elevation in feet amsl
! * * fit
estimated capture zone
boundary stream tubes
resulting from pumping NOTE: MW-4, MW-26, TW4-4, TW4-19 and TW4-20 are pumping wells
HYDRO
GEO
CHEM, INC.
KRIGED 1st QUARTER, 2011 WATER LEVELS
AND ESTIMATED CAPTURE ZONES
WHITE MESA SITE
APPROVED
SJS
REFERENCE H:/718000/
tw27prop/wl0211cz2_rev1 .srf
SCALE IN FEET
EXPLANATION
MW-22
# 5450
O 5557
PIEZ-1
e 5593
MW-31
-^5547
KJ)- 5574
^ 5541
perched monitoring well showing
elevation in feet amsl
temporary perched monitoring well
showing elevation in feet amsl
perched piezometer showing
elevation in feet amsl
perched monitoring well installed April, 2005
showing elevation in feet amsl
temporary perched monitoring well installed
April, 2005 showing elevation in feet amsl
temporary perched monitoring well installed
May, 2007 showing elevation in feet amsl
TWN-4
^5605 temporary perched nitrate
monitoring well showing
elevation in feet amsl resulting from pumping //
ind TW4-20 are pumping wells
HYDRO
GEO
CHEM, INC.
KRIGED 1st QUARTER, 2010 WATER LEVELS
AND ESTIMATED CAPTURE ZONES
WHITE MESA SITE
APPROVED
SJS
REFERENCE H:/718000/
tw27prGp/wl0310cz2_rev1 .srf
* F* sr* / \^—V
t7 fs^
EXPLANATION
01, 2011 70 ug/L chloroform plume boundary
01, 2010 70 ug/L chloroform plume boundary
^TWN-1 temporary perched nitrate monitoring
5598 well showing elevation in feet amsl
O "''W4-1 temporary perched monitoring well
5555 showing elevation in feet amsl
0 MW-32 perched monitoring well showing
5549 elevation in feet amsl
150 300
SCALE IN FEET
NOTE: MW-4, MW-26, TW4-4, TW4-19, and TW4-20 are pumping wells
HYDRO
GEO
CHEM, INC.
KRIGED 1st QUARTER, 2011 WATER LEVEL DETAIL MAP
SHOWING ESTIMATED FLOW DIRECTIONS
AND 01, 2010 AND 01, 2011 CHLOROFORM PLUME BOUNDARIES
WHITE MESA SITE
APPROVED
SJS
REFERENCE H:/718000/
tw27prop/f lowq 1 _chl .srf
/ V
EXPLANATION
01, 2011 70 ug/L chloroform plume boundary
^ 01, 2010 70 ug/L chloroform plume boundary
^ TWN-1
0 150 300
SCALE IN FEET
temporary perched nitrate monitoring
5598 vvell showing elevation in feet amsl
O ''"W4-1 temporary perched monitoring well
5555 showing elevation in feet amsl
0 MW-32 perched monitoring well showing
5549 elevation in feet amsl
NOTE: MW-4, MW-26, TW4-4, TW4-19, and TW4-20 are pumping wells
HYDRO
GEO
CHEM, INC.
KRIGED 1st QUARTER, 2011 WATER LEVEL DETAIL MAP GENERATED
EXCLUDING TW4-14 AND SHOWING ESTIMATED FLOW DIRECTIONS
AND Q1, 2010 AND 01, 2011 CHLOROFORM PLUME BOUNDARIES
WHITE MESA SITE
APPROVED
SJS ^"^^ H:/718000/
tw27propo/flowq1 nol 4_chl.srf
Ql, 2011 70 ug/L
chloroform plume boundary
/ ^ Ql, 2010 70 ug/L
X. ^ chloroform plume boundary
^TWN-1 temporary perched nitrate monitoring
5598 vvell showing elevation in feet amsl
O ''"W4-1 temporary perched monitoring well
5555 showing elevation in feet amsl
0 MW-32 perched monitoring well showing
5549 elevation in feet amsl
A proposed new
well(TW4-27)
0 150 300
SCALE IN FEET
NOTE: MW-4, MW-26, TW4-4, TW4-19, and TW4-20 are pumping wells
HYDRO
GEO
CHEM, INC.
PROPOSED LOCATION OF TW4-27
SHOWING KRIGED 01, 2011 WATER LEVELS AND
Ql, 2011 AND Ql, 2010 CHLOROFORM PLUME BOUNDARIES
(Detail Map)
APPROVED
SJS
REFERENCE
H :/718000/tw27prop/tw27prop.srf
Letter to Mr. Rusty Lundberg
Chloroform RFI Response
June 17, 2011
Page 9
ATTACHMENT 2
DENISO
MINES
TOP OF CASING ELEVATION
= 5607.37 FT AMSL
GROUND SURFACE ELEVATION
= 5605.77 FT AMSL
10
LJ L-
X I— Q_ LJ Q
20 -
30 -
40 -
50 -
60
70
80
90 -
100 -
110
120
4 INCH DIA. PVC CAP
NOMINAL 12 3/4 INCH DIA.
BOREHOLE
10-0"
SURFACE CASING (8 INCH DIA PVC)
PORTLAND CEMENT GROUT
4 INCH DIA SCH 40 FLUSH
THREAD PVC CASING
NOMINAL 6 3/4 INCH DIA.
BOREHOLE
COLORADO SILICA GRAVEL PACK
4 INCH DIA SCH 40 FLUSH-THREAD
0.02 SLOT PVC SCREEN
CUTTINGS 3 7/8" DIAMETER CORE HOLE
NOT TO SCALE
HYDRO
GHEM, INC.
TW4-23
AS-BUILT WELL CONSTRUCTION SCHEMATIC
Approved
SJS
Date Author Date File Name
06/16/11 JAA 06/16/11 7180244A
Figure