DRC-2008-002242 - 0901a0688070e18c

White Mesa U rani urn Mill
Chloroform Monitoring Report
State of Utah
Notice of Violation and Groundwater Corrective Action Order UDEQ
Docket No. UGQ-20-01
3rd Quarter (July through September)
2008
Prepared by:
Denison Mines (USA) Corp. (DUSA)
1050 17th Street, Suite 950
Denver CO 80265
November, 2008
1. INTRODUCTION
This is the Quarterly Chloroform Monitoring Report, as required under State of Utah
Notice of Violation and Groundwater Corrective Action Order State of Utah Department
of Environmental Quality ("UDEQ") Docket No. UGQ-20-01 for the 3rd Quarter of 2008
(the "Quarter") for Denison Mines (USA) Corp.'s ("DUSA's") White Mesa Uranium
Mill (the "Mill"). This Report also includes the Operations Report for the Long Term
Pump Test at MW-4, TW4-19, TW4-15 (MW-26) and TW4-20 for the Quarter.
2. SAMPLING AND MONITORING PLAN
2.1. Description of Monitor Wells Sampled During the Quarter
During the Quarter, the following chloroform contaminant investigation groundwater
samples and measurements were taken:
2.1.1. Groundwater Monitoring
Groundwater Monitoring was performed in all of the chloroform monitoring wells, being
the following wells:
• MW-4 • TW4-11
• TW4-A • TW4-12
• TW4-1 • TW4-13
• TW4-2 • TW4-14
• TW4-3 • TW4-15(MW-26)
• TW4-4 • TW4-16
• TW4-5 • TW4-17 (MW-32)
• TW4-6 • TW4-18
• TW4-7 • TW4-19
• TW4-8 • TW4-20
• TW4-9 • TW4-21
• TW4-10 • TW4-22
The locations of these wells are indicated on the map attached under Tab A.
Wells sampled during this reporting period were analyzed for the following constituents:
• Chloroform
• Chloromethane
• Carbon tetrachloride
• Methylene chloride
• Chloride
• Nitrogen, Nitrate +Nitrite as N
1
2.1.2. Gr.oundwater Head Monitoring
Depth to groundwater was taken in the following wells and/or piezometers during the
Quarter:
a) All of the chloroform contaminant investigation wells listed in paragraph 2.1.1
above on August 26, 2008;
b) The point of compliance monitoring wells under the Mill's Groundwater
Discharge Permit ("GWDP") on August 4-26, 2008.
c) Piezometers-P-1, P-2, P-3, P-4, and MW's 20 and 21 on July 8, 2008. P-5 on
July 8, 2008.
In addition, weekly depth to groundwater measurements were taken in MW-4, TW4-15
(MW-26), TW4-19 and TW4-20, as part of the long term pumping test for MW-4.
2.2. Sampling Methodology, Equipment and Decontamination Procedures
The sampling methodology, equipment and decontamination procedures that were
performed for the chloroform contaminant investigation during the Quarter can be
summarized as follows:
2.2.1. Well Purging and Depth to Groundwater
a) A list is gathered of the wells in order of increasing chloroform contamination.
The order for purging is thus established. Mill personnel start purging with all of
the non-detect wells and then move to the more contaminated wells in order of
chloroform contamination, starting with the wells having the lowest chloroform
contamination; and
b) Before leaving the Mill office, the pump and hose are rinsed with de-ionized
("DI") water. Mill personnel then proceed to the first well which is the well
indicating the lowest concentration of chloroform based on the previous quarters
sampling results. Well depth measurements are taken and the two casing
volumes are calculated (measurements are made using the same instrument used
for the monitoring wells under the Mill's GWDP). The Grundfos pump (a 6 gpm
pump) is then lowered to the bottom of the well and purging is begun. At the
first well, the purge rate is established for the purging event by using a calibrated
5 gallon bucket. After the evacuation of the first well has been completed, the
pump is removed from the well and the process is repeated at each well location
moving from least contaminated to most contaminated. All wells are capped and
secured prior to leaving the sampling location.
2.2.2. Sampling
a) Following the purging of all chloroform investigation wells, the sampling takes
place (usually the next morning). Prior to leaving the Mill office to sample, a
2
cooler along with blue ice is prepared. The trip blank is also gathered at that time
(the trip blank for these events is provided by the Analytical Laboratory). Once
Mill Personnel arrive at the well sites, labels are filled out for the various samples
to be collected. All personnel involved with the collection of water and samples
are the outfitted with rubber gloves. Chloroform investigation samples are
collected by means of dedicated bailers and the wells are purged by means of a
dedicated portable pump. Each quarterly pumping and sample collection event
begins at the location least affected by chloroform (based on the previous
quarters sampling event) and proceeds by affected concentration to the most
affected location. The dedicated portable pump is appropriately decontaminated
prior to each purging sampling event and the QA rinsate sample is collected after
said decontamination but prior to the commencement of the sampling event.
b) Mill personnel use a disposable bailer to sample each well. The bailer is attached
to a reel of approximately 150 feet of nylon rope and then lowered into the well.
After coming into contact with the water, the bailer is allowed to sink into the
water in order to fill. Once full, the bailer is reeled up out of the well and the
sample bottles are filled as follows;
(i) First, a set of VOC vials is filled. This set consists of three 40 ml vials
provided by the Analytical Laboratory. The set is not filtered and is
preserved with HCL;
(ii) Second, a 500 ml sample is collected for Nitrates/Nitrites. This sample is
also not filtered and is preserved with H2S04 (the bottle for this set is
also provided by the Analytical Laboratory);
(iii) Third, a 500 ml sample is collected for Chloride. This sample is not
filtered and is not preserved; and
c) After the samples have been collected for a particular well, the bailer is disposed
of and the samples are placed into the cooler that contains blue ice. The well is
then recapped and Mill personnel proceed to the next well.
DUSA completed (and transmitted to UDEQ on May 25, 2006) a revised Quality
Assurance Plan ("QAP") for sampling under the Mill's GWDP. The GWDP QAP was
reviewed by UDEQ and has been approved for implementation. The QAP provides a
detailed presentation of procedures utilized for groundwater sampling activities under the
GWDP. While the water sampling conducted for chloroform investigation purposes has
been conformant with the general principles set out in the QAP, some of the requirements
in the QAP were not fully implemented prior to UDEQ's approval for reasons set out in
correspondence to UDEQ dated December 8, 2006. Subsequent to the delivery of the
December 8, 2006 letter, DUSA discussed the issues brought forward in the letter with
UDEQ and has received correspondence from UDEQ about those issues. In response to
UDEQ's letter and subsequent discussions with UDEQ, DUSA has incorporated changes
in chloroform QA procedures in the form of a separate document. The chloroform QA
document describes the differing needs of the chloroform investigation program, and is
3
and attachment to the GWDP QAP where QA needs other than those described in the
chloroform QA document are addressed.
2.3 Field Data Worksheets
Attached under Tab B are copies of all Field Data Worksheets that were completed
during the Quarter for the chloroform contaminant investigation monitoring wells listed
in paragraph 2.1.1 above and sampled June 27, 2007.
2.4 Depth to Groundwater Sheets
Attached under Tab C (to be transmitted separately on December 1, 2008) are copies of
the Depth to Water Sheets for the weekly monitoring of MW-4, TW4-15 (MW-26),
TW4-19 and TW4-20 as well as the monthly depth to groundwater monitoring data for
chloroform contaminant investigation wells measured during the quarter. Depth-to­
groundwater measurements which were utilized for groundwater contours are included on
the Field Data Worksheets at Tab B of this report.
3. DATA INTERPRETATION
3.1. Interpretation of Groundwater Levels, Gradients and Flow Directions.
3.1.1. Current Site Groundwater Contour Map
The contour map uses the August 26, 2008 data for the wells listed in paragraph 2.1.2 (a)
above, August 4-26, 2008 data for the wells listed in paragraph 2.1.2 (b), and July, 2008
for the piezometers and wells listed in paragraph 2.1.2 (c) above.
Also included under Tab D is a groundwater contour map of the portion of the Mill site
where the four chloroform pumping wells are located, with hand-drawn stream tubes, in
order to demonstrate hydraulic capture from the pumping
3 .1.2. Comparison of Current Groundwater Contour Maps to Groundwater Contour
Maps for Previous Quarter
The groundwater contour maps for the Mill site for the second quarter of 2008, as
submitted with the Chloroform Monitoring Report for the second quarter of 2008, are
attached under Tab E.
A comparison of the water table contour maps for the Quarter to the water table contour
maps for the previous quarter indicates similar patterns of drawdown related to pumping
of MW-4, MW-26 (TW4-15), TW4-19 and TW4-20. Water levels and water level
contours for the site have not changed significantly since the last quarter, except for a few
locations.
4
Reported decreases in water levels of approximately 5 feet in MW -19 and of
approximately 20 feet in pumping well TW4-20 occurred, and reported increases of
approximately 5 and 6 feet occurred at pumping wells MW-4 and TW4-19, respectively.
Water level fluctuations at pumping wells MW-4, MW-26 {TW4-15), TW4-19, and
TW4-20 are due in part to fluctuations in pumping conditions just prior to and at the time
the measurements are taken. The largest decrease (increase in drawdown) of
approximately 20 feet occurred at TW4-20, and the largest increase (decrease in
drawdown), of approximately 6 feet, occurred at TW 4-19.
3.1.3. Hydrographs
Attached under Tab F are hydrographs showing groundwater elevation m each
chloroform contaminant investigation monitor well over time.
3 .1.4. Depth to Groundwater Measured and Groundwater Elevation
Attached under Tab G are tables showing depth to groundwater measured and
groundwater elevation over time for each of the wells listed in Section 2.1.1 above.
3.1.5. Evaluation of the Effectiveness of Hydraulic Capture
Perched water containing chloroform has been removed from the subsurface by pumping
MW-4, TW4-19, MW-26 (TW4-15), and TW4-20. The purpose of the pumping is to
reduce total chloroform mass in the perched zone as rapidly as is practical. These wells
were chosen for pumping because 1) they are located in areas of the perched zone having
relatively high permeability and saturated thickness, and 2) high concentrations of
chloroform were detected at these locations. The relatively high transmissivity of the
perched zone in the vicinity of the pumping wells results in the wells having a relatively
high productivity. The combination of relatively high productivity and high chloroform
concentrations allows a high rate of chloroform mass removal.
The impact of pumping these wells is indicated by the water level contour maps attached
under Tabs D and E. Cones of depression have developed in the vicinity of the pumping
wells which continue to remove significant quantities of chloroform from the perched
zone. The water level contour maps indicate that effective capture of water containing
high chloroform concentrations in the vicinity of the pumping wells is occurring. As
noted in Section 3.1.2, a decrease in measured water level (increase in drawdown)
occurred at pumping well TW 4-20 and increases in water levels (decreases in
drawdowns) occurred at MW-4 and TW4-19 between the second and third quarters of
2008. Overall, the combined capture of TW4-19, TW4-20, MW-4 and MW-26 {TW4-15)
has not changed significantly since the last quarter. The large increase in drawdown at
TW4-20 has increased the apparent capture zone of this well relative to that of other
nearby pumping wells.
5
Although high chloroform concentrations exist at some locations downgradient of the
pumping wells (for example, near TW4-4), the low permeability of the perched zone at
these locations would prevent significant rates of chloroform mass removal should these
wells be pumped. By pumping at the more productive, upgradient locations, however,
the rate of downgradient chloroform migration will be diminished because of the
reduction in hydraulic gradients, and natural attenuation will be more effective.
3.2. Interpretation of Analytical Results
3 .2.1. Copy of Laboratory Results
Included under Tab H of this Report are copies of all laboratory analytical results for the
groundwater quality samples collected under the chloroform contaminant investigation
on September 10, 2008 along with the laboratory analytical results for a trip blank.
3.2.2. Electronic Data Files and Format
DUSA has provided to the Executive Secretary an electronic copy of all laboratory
results for groundwater quality monitoring conducted under the chloroform contaminant
investigation during the Quarter, in Comma Separated Values (CSV). A copy of the
transmittal e-mail is included under Tab I.
3.2.3 Current Chloroform Isoconcentration Map
Included under Tab J of this Report is a current chloroform isoconcentration map for the
Mill site.
3.2.4 Data and Graphs Showing Chloroform Concentration Trends
Attached under Tab K is a table summarizing chloroform and nitrate values for each well
over time.
Attached under Tab L are graphs showing chloroform concentration trends in each
monitor well over time. As TW4-14 was previously dry and wells TW4-23, 4-24 and 4-
25 have limited data, a trend graph for that well has not been included but will be
included with the 4th Quarter report as sufficient data will have been collected at that
time.
3.2.5 Analysis of Analytical Results
Comparing the analytical results to those of the previous quarter, as summarized in the
table included under Tab K, the following observations can be made:
a) Chloroform concentrations have increased by more than 20% in the following
wells, compared to last quarter: TW4-6, TW4-ll, TW4-18, TW4-19, TW4-22,
and TW4-24.
6
b) Chloroform concentrations have decreased by more than 20% in the following
wells, compared to last quarter: MW-4, TW4-15, TW4-20, and TW4-21;
c) Chloroform concentrations have remained within 20% in the following wells
compared to last quarter: TW4-1, TW4-2, TW4-4, TW4-5, TW4-7, and TW4-
10;
d) Chloroform concentrations at TW 4-16 increased from non-detect to 10 11g/L, and
at TW4-9 decreased from 1.0 11g/L to non-detect; and
e) TW4-3, TW4-8, TW4-12, TW4-13, TW4-14, MW-32 (TW4-17), TW4-23, and
TW4-25 remained non-detect.
In addition, between the second and third quarters of 2008, the chloroform concentration
in well TW4-20 decreased from 30,000 11g/L to 21,000 11g/L, and the concentration in
TW4-21 decreased from 160 11g/L to 120 11g/L. The concentration in TW4-22 increased
substantially from 1,200 11g/L to 6,300 11g/L. Wells TW4-23 and TW4-25 remained non­
detect for chloroform, and the concentration in well TW4-24 increased from 1.4 to 2.9
11g/L. TW4-24, located west of TW4-22, and TW4-25, located north of TW4-21, bound
the chloroform plume to the west and north.
Chloroform concentrations in TW 4-6, which was the most downgradient temporary
perched well prior to installation of temporary well TW4-23, increased from 24 to 39
11g/L. This well has likely remained outside the chloroform plume due to a combination
of 1) slow rates of downgradient chloroform migration in this area due to low
permeability conditions and the effects of upgradient chloroform removal by pumping,
and 2) natural attenuation. Both TW4-6 and TW4-23 bound the chloroform plume to the
south.
3.3. Quality Assurance Evaluation And Data Validation
Quality assurance evaluation and data validation procedures in effect at the time of
sampling were followed. These involve three basic types of evaluations: field QC
checks; Analytical Laboratory checks; and checks performed by DUSA personnel, as
described below.
3.3 .1 Field QC Checks
Field Quality Control samples for the chloroform investigation program consist of a field
duplicate sample, a field blank and a trip blank. These check samples are to be generated
for each quarterly sampling episode. During the 3rd Quarter of 2008 duplicates (TW4-65,
duplicate of TW4-3 and TW4-70, duplicate of TW4-17), a DI blank (TW4-60) and a trip
blank were collected and analyzed. The results of these analyses are included with the
routine analyses under Tab H.
7
3.3.2 Analytical Laboratory QA/QC Procedures
The Analytical Laboratory has provided summary reports of the analytical quality
assurance/quality control (QA/QC) measurements necessary to maintain conformance
with NELAC certification and reporting protocol. The Analytical Laboratory QA/QC
Summary Report, including copies of the Mill's Chain of Custody and Analytical
Request Record forms, for the September sampling event, are included under Tab H.
3.3.3 Mill QA Manager Review
The Mill QA Manager, which, for these sampling events was DUSA's Manager of
Environmental Affairs, performed four types of reviews: a determination of whether Mill
sampling personnel followed Mill sampling procedures; a review of the results from the
Field QC Checks; a review of analytical reports for holding times and qualifying
indicators for the data; and a review of the Analytical Laboratory QA/QC analysis. The
results of the QA Manager's review are discussed below.
a) Adherence to Mill Sampling SOPs
On a review of adherence by Mill personnel to the sampling procedures summarized in
Section 2.2 above, the QA Manager concluded that such procedures had been followed.
b) Results From Field QC Checks
The duplicate samples of TW4-3 and TW4-17 indicated a relative percent difference
within the prescribed standard of 20%. However, chloroform presence was indicated in
the field blank and rinsate samples. The matter of continued chloroform presence in
these field blank and rinsate samples in under investigation on the part of the QA
Manager and the results of that investigation and corrective actions taken will be included
with the 4th Quarter, 2008 Report.
c) Review of Analytical Laboratory QA/QC Analysis and Analytical Reports
The QA Manager reviewed the Analytical Laboratory's QA/QC Summary Reports and
made the following conclusions;
(i) Check samples were analyzed for each method used in analyzing the
Chloroform investigation samples. These methods were:
Parameter
Nitrogen, (Nitrate + Nitrite as N)
Chloroform,
Carbon tetrachloride
Chloromethane
8
Method
E353.2
E624
E624
E624
Methylene chloride
Chloride
E624
A4500-CL B
(ii) The check samples included at least the following: a method blank, a
laboratory control spike (sample), a matrix spike and a matrix spike
duplicate;
(iii) All qualifiers, if any, and the corresponding explanations in the summary
reports are reviewed by the QA Manager. The only qualifiers reported
were for matrix interference in some of the analyzed monitoring location
samples, however, the reporting limit was maintained below the
parameter standard in these instances.
(iv) The laboratory holding time for all analyses was within chloroform
specification and sample temperature was acceptable upon receipt.
4. LONG TERM PUMP TEST AT MW-4, TW4-15 (MW-26), TW4-19 AND
TW4-20, OPERATIONS REPORT
4.1. Introduction
As a part of the investigation of chloroform contamination at the Mill site, IUSA has been
conducting a Long Term Pump Test on MW-4, TW4-19, TW4-15 (MW-26) and TW4-
20. The purpose of the test is to serve as an interim action that will remove a significant
amount of chloroform-contaminated water while gathering additional data on hydraulic
properties in the area of investigation. The following information documents the
operational activities during the Quarter.
4.2. Pump Test Data Collection
The long term pump test for MW-4 was started on April 14, 2003, followed by the start
of pumping from TW4-19 on April 30, 2003, from TW4-15 (MW-26) on August 8, 2003
and from TW4-20 on August 4, 2005. Personnel from Hydro Geo Chern, Inc. were on
site to conduct the first phase of the pump test and collect the initial two days of
monitoring data for MW -4. IUSA personnel have gathered subsequent water level and
pumping data.
Analyses of hydraulic parameters and discussions of perched zone hydrogeology near
MW-4 has been provided by Hydro Geo Chern in a separate report, dated November 12,
2001, and in the May 26,2004 Final Report on the Long Term Pumping Test.
Data collected during the Quarter included the following:
a) Measurement of water levels at MW-4, TW4-19, TW4-15 (MW-26), and TW4-
20 on a weekly basis, and at selected temporary wells and permanent monitoring
9
wells on a monthly basis (See Section 3.1 and Tabs B and C for a discussion of
the water levels);
b) Measurement of pumping history:
(i) pumping rates
(ii) total pumped volume
(iii) operational and non-operational periods;
c) Periodic sampling of pumped water for chloroform and nitrate & nitrite analysis
and other constituents, as discussed in detail in Section 3.2 above.
4.3. Water Level Measurements
Beginning August 16, 2003, the frequency of water level measurements from MW-4,
TW4-15 (MW-26), and TW4-19 was reduced to weekly. From commencement of
pumping TW4-20, water levels in that well have been measured weekly. Depth to
groundwater in all other chloroform contaminant investigation wells is monitored
monthly. Copies of the weekly Depth to Water monitoring sheets for MW -4, TW 4-15
(MW-26), TW4-19 and TW4-20 and the October and December monthly Depth to Water
monitoring sheets for all of the chloroform contaminant investigation wells are typically
included under Tab C but will be transmitted separately on December 1, 2008. Monthly
depth to water measurements for September are recorded in the Field Data Worksheets
included under Tab B.
4.4. Pumping Rates and Volumes
4.4.1. MW-4
Approximately 81,400 gallons of water were pumped from MW-4 during the Quarter.
The average pumping rate from MW-4, when the pump was pumping, was approximately
4.0 gpm throughout the Quarter. The well is not purging continuously, but is on a delay
device. The well purges for a set amount of time and then shuts off to allow the well to
recharge. Water from MW -4 was transferred to the Cell 1 evaporation pond through a
pipeline installed specifically for that purpose. At the end of the 3rd Quarter, 2008, and
since commencement of pumping on April 14, 2003, an estimated total of approximately
1, 726,140 gallons of water have been purged from MW -4.
10
4.4.2. TW4-19
Approximately 529,020 gallons of water were pumped from TW4-19 during the Quarter.
The average pumping rate from TW 4-19, when the pump was pumping, was
approximately 6.0 gpm throughout the Quarter. The pump in this well is operating on a
delay. It pumps for approximately one and a half minutes and then is off for two to three
minutes. Water from TW4-19 was directly transferred to the Cell 1 evaporation pond
through a pipeline installed specifically for that purpose. At the end of the 1st Quarter,
2007, and since commencement of pumping on April 30, 2003, an estimated total of
approximately 8,633,530 gallons of water have been purged from TW4-19.
4.4.3. TW4-15 (MW-26)
Approximately 61,280 gallons of water were pumped from TW4-15 (MW-26) during the
Quarter. The average flow rate from TW4-15, when the pump was pumping, was
approximately 1.5 gpm throughout the Quarter. The well is not purging continuously, but
is on a delay device. The well now purges for a set amount of time and then shuts off to
allow the well to recharge. The water is directly transferred to the Cell 1 evaporation
pond through a pipeline installed specifically for that purpose. At the end of the 1st
Quarter, 2006, and since commencement of pumping on August 8, 2003, an estimated
total of approximately 1,218,240 gallons of water have been purged from TW 4-15.
4.4.4. TW4-20
Approximately 53,260 gallons of water were pumped from TW4-20 during the Quarter.
The average flow rate from TW4-20, when the pump was pumping, was approximately
6.0 gpm throughout the Quarter. The well is not purging continuously but is on a delay
device. The well pump is set on a water elevation device. When the water reaches a set
point, the pump turns on until the water level drops to another set point. The water is
directly transferred to the Cell 1 evaporation pond through a pipeline installed
specifically for that purpose. Since commencement of pumping on August 4, 2005, an
estimated total of approximately 935,420 gallons of water have been purged from TW 4-
20.
4.5 Daily Inspections
Denison has submitted an Operations and Maintenance Plan, Chloroform Pumping
System, White Mesa Mill, Blanding, Utah, Revision 1.0 to UDEQ for approval. Upon
approval of that plan, the Mill will commence documenting its daily inspections of the
operational status of the chloroform pumping wells on the daily inspection form, an
example of the form of which is attached as Tab M.
11
4.6 Operational Problems
No operational problems in the pumping wells were reported during the 3rd Quarter, 2008
period.
4.7 Conditions That May Affect Water Levels in Piezometers
No water was added to any of the three wildlife diversion ponds during the Quarter.
4.8 Chloroform Analysis
Monthly chloroform sampling ceased on November 8, 2003. From that time all
chloroform contaminant investigation wells were sampled on a quarterly basis. The
sample results are discussed above in Section 3.2.
5. CONCLUSIONS AND RECOMMENDATIONS
The water level contour map for the Quarter indicates that effective capture of water
containing high chloroform concentrations in the vicinity of the pumping wells is
occurring.
Between the second and third quarters of 2008, the chloroform concentration in well
TW4-20 decreased from 30,000 j..tg/L to 21,000 j..tg/L, and the concentration in TW4-21
decreased from 160 j..tg/L to 120 j..tg/L. The concentration in TW4-22 increased
substantially from 1,200 j..tg/L to 6,300 j..tg/L. Fluctuations in concentrations in these
wells are likely related to variations in pumping in TW4-20 and nearby wells, and their
location near the suspected former office leach field source area. Regardless of these
measured fluctuations in chloroform concentrations, sampling of temporary wells TW 4-
24 (located west of TW4-22) and TW4-25 (located north of TW4-21), indicated these
wells remain outside the chloroform plume and thus bound the plume to the west and
north. Chloroform was not detected at TW4-25 and was detected at a concentration of
less than 3 j..tg/L at TW4-24.
Although there has been a general increase in chloroform concentrations in TW4-22 since
last year, the reported relatively substantial increase from 1,200 to 6,300 j..tg/L between
the second and third quarters seems anomalous. Fourth quarter sampling results should
help indicate whether or not this is a short term fluctuation.
Continued pumping of TW4-19, TW4-20, MW-4, and MW-26 (TW4-15) is
recommended. Pumping these wells, regardless of any short term fluctuations in
concentrations detected at the wells (such as at TW4-20), helps to reduce downgradient
chloroform migration by removing chloroform mass and reducing average hydraulic
gradients, thereby allowing natural attenuation to be more effective.
12
The chloroform concentration at downgradient well TW 4-6 increased from 24 to
39 �giL. Although fluctuations in concentrations have occurred, this well has likely
remained outside the chloroform plume due to a combination of 1) slow rates of
downgradient chloroform migration in this area due to low permeability conditions and
the effects of upgradient chloroform removal by pumping, and 2) natural attenuation.
Chloroform remained non detect at downgradient temporary well TW4-23. Both TW4-6
and TW4-23 bound the chloroform plume to the south.
13
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Page40of41
ATTACHMENT! WHITE MESA URANIUM MILL FIELD DATA WORKSHEET FOR GROUND WATER
Description of Sampling Event: 3 �et Ow, w r£ ,, cVrPcF-et�. .........
Sampler
Location (well name) /Jttd �/ Na�e and initials ""1A11r�,a- /.l j, �� .... �
Date and Time for Purging :_._-------and Sampling (if different) 7 · )IJ ·tJ <if
Well Purging Equip Used: pump or _bailer Well Pump (if other than Bennet) J,J;/,j):j
Sampling Event 61.,-ttJ cUfr{llfMVY'= Prev. Well Sampled in Sampling Event ;(J fJ
pH Buffer 7.0 1-0 pH Buffer4.0. ___ -!.,;4-:_o ____ _
Specific Conductance Cfq1 uMHOS/cm
Depth to Water Before �gjng 1$ .1 t
Conductance (avg)'-----"-----'"-
Well Water Temp. (avg) ____ �
Well Depth'-.-.----------
Casing Volume (V) 4" Well:. ___ _.(.653h)
3" Well: -(.367h)
pH of Water (avg).-'.'----· _____ _ Redo� Potentiai $h). -Turbidity __ _
Weather Cond.dcwJ 1 {l,qf, 0 Ext' I Amb. Temp.(prior to sampling event) / L C.
Time: lOSS"':: Gat. Purged.__ __ _
Conducta.lce d. 0 CJ (q
pH L, 9':/
Temperature \ L\ ''lS }
L\1-?.:::> Redox Potential (Eh)�-.:.:::b�---
Time:_-+---
"'\--.......;o--Gal. Purged.___,---'..__ _ _,__
�
pH
Te
(�: .. ..
· .. ·
..
.. "' --: .. . ,
_,
.!
( (·
Mill-Groundwater Discharge Permit
Groundwater Monitoring
Date: 11.17.06 Revision: 1
Quality Assurance Plan (QAP) Page41 of41
Turbidity ________ _ Turbidity _________ _
Volume of Water Purged When Field Parameters are Measured.,__ ________ _
Pumping Rate Calculation
Flow Rate (Q), in gpm. ----&00= =�------------
Time to evacuate two casing volumes (2V) T�2WQ=---------------
Number of casing volumes evacuated (if other than two)·----�-------
If well evacuated to dryness. number of gallons evacuateJ:l,__ __________ _
Name of Certified Analytical Laboratory if Other Than Energy I,.abs. __ �---====�----
I!� of Sam(!le Saln(!le S8mele Volume Filtered Preservative Added
VOCs
Nutrients neavv Metals
All Other Non�
Radioloaics ..
Gross Alpha Other {specify) �ed!Ri:i. ;(dbf�t1it.
Taken
{drde}
(y) N � N y 1ft.» y t:V
y w � N
(indicate ·it odier 'f�Uili ·as sneclfied belowl
.• '
3x40ml
lOOml 2SOfui
250ml
l,OOOml
Sample volume
(circle} (cirde)
y ® .. � HCL 00 N
y w .H2S04 (Y) N
y N HN� y N
y N No Preservative Added
y N H:zS04 y N
y �) y fYI
If a preservative is used, Specify Type and Quantity of�servative:
(· (
Mill-Groundwater Discharge Pennit
Groundwater Monitoring
Date: 2.25.07 Revision: 2
Quality Assurance Plan (QAP)
ATTACHMENT 1 WHITE MESA URANIUM MILL FIELD DATA "tORKSHEET FOR GROUND WATER
Description of Sampling Event: .3 e.� Wc..{}_Tfi? c...h loro'Povt.v"'-
Page40of41
Sampler
Location (well name) ·"t*I.VLi -

l

N�e and initials 1iir1Me II 4 f<.ytw P
Date and Time for Purging C/!1 I tl g and Sampling (if different) 1//tl /tJ /?. . ,, . '
Well Purging Equip Used: .Kpump or _bailer Well Pump (if other than Bennet) (..,ruM( h.>
Prev. Well Sampled in Sampling Event 1'W'-Ir 7
pH Buffer 7.0. ___ '"1.'-''-"'6 ___ _ pH Buffer4.0. __ ..!....lj..;..:. tl:..__ ____ _
Specific Conductance o/'17 uMHOS/cm Well Depth._,., _ __.:.1,.!..1 .!..\ -------
Depth to Water Before Pur;gin.c.g--='-�l:...:.·..:::C..'-y'---Casing Volume (V) 4" Well: 3,2 .l3 (.653h) (.367h) 3'' Well: AJ/h Conductance(avg)7. ___ .......;...o __ � pH of Water (avg)."""'··----==----
WeD Water Temp. (avg) ____ ___ Redo" Potential (Eh) �urbidity __ --_
Weather Cond. C I o I.A.� Ext' I Amb. Temp.(prior to sampling event)
Time: Gal. Purged
Conducta(lce d.,d..lt\
pH b-73
Temperature lL\-]d-.
Redox Potential (Eh) _ _,:l_�""'"l ___ _
(·•· .. .. .
· ...
-·
( (.
Mill-Groundwater Discharge Permit Groundwater Monitoring Date; 1L17.06 Revision: 1
Quality Assurance Plan (QAP) Page41 of41
Volume of Water Purged \Wtu FiaiElltimlmsters 818 MlmsiiEe8 G. b
Pumping Rate Calculation
Flow Rate (Q), in gpm. A S/60 = ------le�:...._ ___ _
Time to evacuate two casing volumes (2V)
T=2VIQ= il M�o
Number of casing volumes evacuated (if other than two)__,......:.N�/ A:..:......--:---------
If well evacuated to dryness, nuinber of gallons evacuate.d,__�N�I..,A�-.-_______ _
Name of Certified Analytical Labomtory if Other Than Energy Labs'--"A/.�it""';.;.:'I:':::.._ ____ _
TvPe of Samll)e Samele Samj!le Yolume Filtered Preservative Added
VOCs Nutrients Heavy Metals ..
All Other Non-
Radiologies -.
Gross Alpha Other (specify)
htt.wul :b.It3 :":ik
Taken
!circle}··
(}? N ('i} N._ y ®J y �
y ... (N> ® N
(indicate if other "tluili as soeeified
IJelowj
3x40ml lOOml 250ihl 250ml . . l,OOOml
Sample volume
(circle} (ci�cle)
y. (b1l .... HCL (Y) N y MJ .H:zS04 OCIN y N HN03 y N y N No Preservative Added
y N HzS04 y N y @ y ®
If a preservative is used,
Specify Type and
Quantity of�ervative:
Mill-Groundwater Discharge Pennit
Groundwater Monitoring
Quality Assurance Plan (QAP)
Date: 2.25.07 Revision: 2
Page40of41
ATTACHMENT 1
WHITE MESA URANIUM MILL FlEW DATA ""{ORKSHEET FOR GROUND WATER.
Descliption of Sampling Event: 3 e.: Ov.u. a.u.? c..h I o c oF D'll.v"'-
Sampler
Location (well name) TW'=J • d. Na�e and initials :1Ar1aoe II 4 1'2-y&..t P
Date and Time for Purging q I 1/11 8' and Sampling (if different) 1/JIJ / tJ & . r 1 . ,
Well Purging Equip Used: .Kpump or _bailer Well Pump (if other than Bennet) (.,aMcl 6�
Pl-ev. Well Sampled in Sampling Event JWY�I...\
pH Buffer 7.0 __ ___,7.c...;..-=c.6 ___ _ pH Buffer4.0 __ -.::.t;...;...IJ::;.__ ____ _
Specific Conductance 19 7 uMHOS/cm Well Depth..,.. _ _,I'-"4-:::.J.\-'-', JL..,":>.L-------
Depth to Water Before Purging b q. 4 �
Conductance (avg)"-___ ......_ __ _._
Well Water Temp. (avg)'-----­
Casing Volume (V) 4" Well: '13.7;).
3" Well: NIIJ (.653h)
(.367h) pH ofWater (avg)'-''--------
Redox. Potential (Eh) __ Turbidity __ _
WeatherCond. C. I o ...... ail Ext' IAmb. Temp.(prior to sampling event) :l.l�<; ·
Time: Gal. Purged
Conductance :;),1.\.l'-
pH faA8
Temperature (t..l/1(;,
Redox Potential (Eh) __ '$:.5,_5,__ __ _
Turbidity ___ 4_,_.:J. ____ _
(··; .. . •
. � ..
.·