DRC-2013-004014 - 0901a068803fd56b

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, x r ENERGY FUELs
VIA EMAIL AND OVERNIGHT DELIVERY
March 29,2013
Mr. Bryce Bird
Director, Utah Division of Air Quality
State of Utah Department of Environmental Quality
195 North 1950 West
Salt Lake City~ UT 841 16
Re: White Mesa Uranium Mill,
Energy Fuels Resources (USA) Inc.
225 Union Blvd. Suite 600
Lakewood, CO, US, 80228
303 974 2140
vvww .energyfuels. com
National Emissions Standards fot· Radon Emission from Operating Mill Tailings
Transmittal of2012 Annual Radon Flux Monitoring Reports
Dear Mr. Bird:
This letter transmits Energy Fuels Resources (USA) Inc.'s ("EFRI's") radon-222 flux monitoring reports·
for the year 2012 for two tailings cells, Cells 2 and 3, at the White Mesa Uranium Mill (the "Mill").
EFRI has submitted notices to the Utah Division of Air Quality ("DAQ") on August 22,2012 and March
8, 2013, explaining the indirect change of control that resulted in EFRI's change of name from Denison
Mines (USA) Corp. to Energy Fuels Resources (USA) Inc.
Introduction
Tbc result of the 2012 radon-222 flux monitoring fo r Cell 2 was 25.9 pCi m-2 s-1 (averaged over four
monitoring events) and for Cell 3 was 18 pCi m-2 s-1• The measured radon flux from Cell 2 in 2012
therefore exceeded the standard set out in 40 CFR 61.252 of 20 pCi m-2 s-1. Cell 3 was in compliance
with this standard for 2012.
EFRL has evaluated these results and has concluded that the increase in radon-222 flux from Cell 2 that
has resulted in this exceedance is most likely the unavoidable result of Cell 2 dewatering activities
mandated by the Mill's State of Utah Groundwater Discharge Permit (the "GWDP"). There appear to
have been no other changes in conditions at Cell 2 that could have caused this increase in radon from
Cell 2_ These conclusions are supported by evaluations performed by SEN ES Consultants Limited
("SENES''), who were retained by EFRI to assess the potential effects of dewatering on the radon flux
from Cell 2 and to provide calculations of the thickness of the temporary cover required to achieve the
radon flux standard during the dewateting process. These conclusions and analyses are discussed below.
Based on this analysis, EFRI proposes actions and a timeframe to bring CeLl 2 into compliance with the
standard set out in 40 CFR 61.252, as described below.
\\Dmcusdefs1 \mill\WMM\Required Reports\NESHAPS Reports\2012 NESHAPs\03.29.13 transmtl
Radon Flux monitoring final\03 22 13 transmtl Radon Fl ux monitoring 3.28.13 final.doc
Letter to B. Bird
March 29,2013
Page 2 of 15
Facility History
The Mill has constructed four impoundmen ts since its inception in 1980. Two impoundments, Cells 3
and 4A, are currently in operation as tailings cells. Two impoundments, Cells I and 48, are in operation
as evaporative ponds. The remaining impoundment, tailings Cell 2, which is fi lled with tailings and
covered with an interim soil cover, is no longer in operation.
Cell 2 and 3, which are 270,624 m2 (approximately 66 acres) and 288,858 m2 (approximately 71 acres),
respectively, were constructed prior to December 15, 1989 and are considered "existing impoundments''
as defined in 40 CFR 61.251. Radon flux from Cells 2 and 3 is monitored annually, as discussed below.
The Mill has submitted annual radon flux monitoring results for Cells 2 and 3 since 1992, pursuant to 40
CFR 61.254 Subpart W radon emissions reporting requirements. The radon monitoring events have
consisted of 100 separate monitoring points at which individual radon flux measurements have been
made by collection on carbon canisters. The individual radon flux measmemen ts are averaged to
determine compliance with 40 CFR Part 61 Appendix B, Method 115.
Cells 4A and 4B were constructed after December 15, 1989, and are subject to the work practice
standards in 40 CFR 61.252(b)(1 ), which require that the maximum sw'face area of each cell not exceed
40 acres. For this reason, Cells 4A and 48 are not required to undergo annual radon flux monitoring.
As discussed below, the Mill has been required dewater the Cell 2 slimes drain under the Mill's GWDP.
Changes were made in the pumping procedures in mid-2011 that resulted in an acceleration of
dewatering since that time. No other changes appear to have occurred in condition, use, or monitoring
of Cell 2 that could have resulted in an increase in radon f1ux from the cell.
Field Results
History of Cell 2 Dewatering
Soil stockpiled at the site (loam to sandy clay -referred to hereinafter as ''random fill") was used to
partially cover the tailings in Cell 2 until 2007, when Cell 2 was completely covered by random "fill. As
part of developing the final reclamation actions required to achieve the radon flux standard of20 pCi m·2
s·l, a final engineered cover was designed by TITAN Environmental (1996), and an updated design has
recently been proposed by MWH Americas Inc. (2011), which is currently under review by the Utah
Department ofEnvironmental Quality, Division of Radiation Control ("DRC").
The Utah Division of Water Quality issued GWDP UGW-370004 in 2005 . Under Part I.D.3 of the
cw-rent GWDP, EFRI h<:\,s been required to accelerate dewatering of the solutions in the Cell 2 slimes
drain. Specifically, according to Part l.D.3b)l):
"Slimes Drain Maximum Allowable Head -the Permittee shall at all times maintain the
average wastewater recovery head in the slimes drain access pipe to be as low as
Letter to B. Bird
March29, 2013
Page 3 of15
reasonably achievable (ALARA) in each tailings disposal cell, in accordance with the
currently approved DMT Monitoring Plan."
Part 1.0.3b)3) further requires that to demonstrate compliance the Mill must meet the conditions in an
equation (Equation I) specified in that Part, which is designed to demonstTatc that the rolling average of
the slimes drain solution elevation decreases continually. Per Part T.0.3) c)
'"Failure to satisfy conditions in Equation I shall constitute DMT failure and non-
compliance with this Permit."
As required by Part l.E.7 b) of the GWDP, the level of tailings solutions or· "slimes drain recovery
elevation" ("SORE") in Cell 2 is measured at the centerline of a slimes drain access pipe located near
the central part of the south dike. f.igure 1 provides a plot of SORE values from 2009 to the present,
taken from the Mill's Fourth Quarter 2012 Discharge Minimization Technology ("DMT ') Monitoring
Report.
Cell 2 SDRE level was monitored monthly from January 2008 through July 2011. During that time
period, the need to shut down slimes drain solution pumping in order to achieve the solution level
equilibrium required for the slimes drain level measurement resulted in the slimes drain pump being shut
down as much as 11 weeks per year or more than 20 percent of the time. The GWDP was modified in
2011 to require quarterly rather than monthly SORE level monitoring, to accommodate as much
pumping time, and as rapid a solution level reduction, as possible. As a result of the reduced monitoring
frequency and increased pumping up-time, the Mill was able to pump the slimes drain more days per
month or quarter, producing a more rapid decrease in water level commencing in mid-2011. This more
rapid decrease in solution level is indicated in Table 1 and Figure 1 .
The average water level in the Cell 2 slimes drain standpipe for each of the years 2008 through 2012 is
indicated in Table 1. These data indicate that water levels in Cell 2 have decreased approximately 3.25
feet (5600.56 to 5597.31 fmsl) since 2008. or thi s decrease in water level, approximately 1 foot
occurred between 2010 and 2011 , reflecting the improved dewatering that commenced patt way through
2011, and approximately 2 feet between 2011 and 2012, reflecting improved dewatering for all of20 12.
History ofCel/2 Radon Flux Monitoring
Results of annual monitoring for the calendar years 1992 through 2012 are sLUnmarized in the attached
Table 3. Versar, Inc. provided the field measurements and report for the 1992 calendar year. Tell co
Environmental, Inc. ("Tellco") has performed the field measurements, analysis, and reporting every year
since 1993. Annual monitoring has been performed during the summer dry season, typically between
June and August. Tellco field m onitoring for the last 11 calendar years has been performed consistently
in June each year.
As indicated by the data in Table 3, the radon flux measured at Cell 2 has been below the radon flux
limit of20 pCi/m2sec required by 40 CFR 61.254 Subpart W. However, the measured radon flux began
to increase steadily, while remaining below the emissions standard, since approximately 2009. Table 3
a lso provides the annual precipitation rates during the 1992 to 2012 monitoring period. While 20 ll and
Letter to B. Bird
March 29, 2013
Page 4 of 15
2012 were relatively dry years, and dryness of the interim cover on Cell 2 could contribute to increased
radon flux, the precipitation for those years was not outside the norm. Further, precipitation increased
from 2011 to 2012, while radon flux increased over the same time period, which would not be expected
if drought conditions were the primary contributing factor of the increased radon flux. We have
therefore concluded that the increased radon flux from Cell 2 is not likely due to changes in annual
precipitation rates.
Tellco performed the 2012 radon flux sampling during the second quarter of2012 in the month of June.
On June 25 of2012, Tellco advised EFRJ that the average radon flux for Cell 2 from samples taken in
June 2012 was 23.1 pCi/m2scc, which average flux , by itself, would have exceeded the Subpart W
requirement.
40 CFR 61.253 provides that:
"When measurements are to be made over a one year period, EPA shall be provided with
a schedule of the measurement frequency to be used. The schedule may be submitted to
EPA prior to or after the first measurement period. EPA sha11 be notified 30 days prior to
any emissions tests so that EPA may, at its option, observe the test."
Part 61 Appendix B, Method 115 provides that if a frequency greater than annual sampling is used, the
samples may be collected on weekly, monthly or quarterly intervals.
EFRI chose to collect additional samples from Cell 2:
l. to confinn the June 2012 results, and
2. to make additional measurements to evaluate, if possible, any data trends.
EFRI advised DAQ by notices on August 3, and September 14, 2012 that EFRl planned to collect
additional samples ii·01n Cell 2 in the trurd and fourth quarters of 2012. These samples were coll ected
on September 9, October 21, and November 21, 2013, respectively. The fourth sampling set was
performed in November 2012 to ensure that weather (particularly snow cover) would not interfere with
the sampling or affect the results. The Tellco reports resulting from the four radon flux tests in June,
September, October, and November 2012 are provided in Attachments 1 A, I B, l C, and 1 D,
respectively. As the June monitoring for Cell 3 indicated that it was in compliance with the standard,
further monit01ing of Cell 3 was not performed in September or October, 2013. The Tellco reports
provide the results of the compliance calculations required in 40 CFR 61.253 and the input parameters
used in making the calculation, and also include the following information required by 40 CFR 61.254
(a): the name and location of the mill, the name of the person (EFRI) responsible for the operation of
tl1e facility, the name of the person preparing the report; and the results of the testing conducted,
including the results of each measurement.
Letter to B. Bird
March 29,2013
Page 5 of 15
Test Pit Data Collected in 2013
In an attempt to identify causes ofthe trend in radon flux, EFRT excavated a series of 10 test pits in the
Cell 2 sands to collect additional information needed to ascertain factors affecting radon flow path and
nux. Mill personnel performed the excavations and collected the additional data during the period from
February 15 to 19, 2013. Figure 2 is a schematic drawing of Cell 2 indicating the location of test pits
excavated to collect additional information. Each selected test pit location corresponded to, or was
adjacent to, a location used for one of the radon flux canisters used for the four series of nux
measurements collected during 2012, and each location was confirmed and documented by GPS survey
instrwnent. The locations were selected to include locations with previously reported high and low
radon fluxes, and to provide a distribution of samples representative of the entire area of the cell.
The types of data collected at each location were:
• GPS coordinates of the flu.x test point/test pit location
• Elevation at top of cover soils
• Elevation at top of tailings sands
• Elevation at which tailings solution were reached
• Gamma reading in ur/hr at or above the surface of the soil cover before the test pits were
excavated.
A summary oftest pit results is provided in Table 2. The results are depicted graphically in Figure 3.
Evaluation ofPotential Factors Affecting Radon Flux
As mentioned above, EFRI evaluated a number of factors to identify potential conditions that may have
had an effect on the trend in Cell 2 radon flux.
The results of this evaluation are summarized below:
1. Annual precipitation during the period in question does not appear to be a signiticant factor.
2. Cell 2 was not in operation, pending final reclamation, with interim soil cover over the entire
cell, during the entire period. That is, it received no tai lings, and therefore ore grades and Mill
operations had no effect on Cell 2 during this period.
3. The same contractor and laboratory performed all sampling and flux measurements during the
period evaluated. That is, there were no changes in the source of flux data.
4. SDRE was measured in the same slimes drain access pipe during the entire period.
5. The only change to the Cell 2 system was the acceleration of dewatering via more effective
pumping of slimes drain solutions commencing in mid 2011.
6. No other changes were identified.
The above evaluation led EFRI to further analyze the relationship between historic radon flux data and
historic slimes drain water level for Cell 2. Table 2 summarizes the data for the years of Cell 2
dewatering, from 2008 to the present.
Letter to B. Bird
March 29, 2013
Page 6 of 15
Table 1 indicates that a lowering of the water level in Cell 2 has resulted in an increase in the average
radon flux and an increase in water level has resulted in a decrease in the average radon flux. Changes
in radon flux have consistently been inversely proportional to changes in water levels in Cell 2 since
2008. For the last three years the change in radon flux has been between 3 and 5 pCi/m2sec per each
foot of change in water level. It is also noteworthy that the significant increases in radon flux from Cell
2 between 2010 and 2011 and between 2011 and 2012 coincide with the periods of improved
(accelerated) dewatering of Cell 2.
Based on these field observations, EFRI has concluded that the increase in radon flux from Cell 2 in
recent years, which has resulted in the exceedance of the 20 pCi m·2 s·1 standard in 40 CFR 61.252 (a) in
2012 is most likely caused by the dewatering activities mandated by the Mill 's GWDP.
SENES Evaluation
EFRJ requested tJ1at SENES evaluate the available site specific data described above to:
1. Assess the potential effects of dewatering on the radon flux from Cell 2 during the dewatering
process, and
2. Provide illustrative calculations of the thickness of a temporary cover needed to achieve the
radon flux standard of20 pCi m·2 s·', during the dewatering process.
SENES' report is provided in Attachment 2, and its conclusions are summarized in the sections below.
The SENES study confirmed that, as expected on the basis of diffusion principles, the radon flux from
the surface of the Cell2 tailings is expected to increase as dewatering progresses.
The test pit measurements taken in February 2013 were used to determine the approximate thickness of
cover and thickness of dry tailings (i.e., thickness of tailings above the solution level) at each of the ten
test points. The test pit study indicated:
• An average cover thickness of 4.35 feet
• An average dry tailings thickness of 11.74 feet
• An average cover diffusion coefficient of 0.01 cm2/sec, which is comparable to the perfonnance
of random fill at 80 to 95% compaction.
These results were used in evaluations performed by SENES to estimate a theoretical radon t1ux from
the covered tailings at Cell 2 for various depths (thicknesses) of dry tailings, and to predict future
increases in radon flux as a function of decreases in water levels.
SENES noted that as the water in tailings pore space is replaced with air as a result of dewatering, more
radon becomes available for exchange with air, as radon is better able to diffuse through the tailings to
the air/tailings surface. When the pore space in porous material is filled with water the diffusion
coefficient is about Ill 00111 of that in pores filled with air. Therefore, it is expected that as the tailings
dewatering progresses, radon flux to air will also increase. However, due to the haJf life of radon (3 .82
days), a tailings thickness greater than about 3 to 5 meters is effectively equivalent to an infinitely thick
Letter to B. Bird
March 29, 2013
Page 7 of 15
radon source, because the radon generated below such thicknesses will decay before it can diffuse
through to the surface of the tailings. SENES therefore concluded that increasing dry tailings thickness
as a result of dewatering Cell 2 should result in increased radon flux, but that, given the current average
tailings thickness in Cell 2 of 11.74 ft, the anticipated radon flux is nearing its theoretical maximum.
This means that fu rther dewatering of Cell 2 should be expected to result in increased radon :flux, but at
a decreasing rate.
SENES also noted that the dewatering operation is expected to take several years to complete, and, if
addition of temporary cover of random fill is not feasible, exceeding the radon flux standard wi ll be an
unavoidable but temporary consequence of the dewatering process. This elevated radon flux will persist
through dewatering but would be reduced to below the regulatory limit once the final tailings cell cover
is in place.
In order to explore potential interim actions that could be taken to maintain radon flux within the 20 pCi
m·2 s·1 standatd, the SENES study evaluated the extent to which radon emanations from the cell can be
reduced by increasing the th ickness of the cutTent interim cover on Cell 2. SENES' analysis concluded
that:
(a) the addition of approximately 0.5 feet of random fill cover (at between 80 and 95% compaction)
to the current interim cover would be expected to reduce the average radon fl ux from its current
rate of approximately 26 pCi m·1 s·1 to less than 20 pCi m·2 s·1,
(b) the addition of approximately 1.0 feet of random till cover (at 80 to 95% compaction) to the
current interim cover would be expected to reduce the average flux of approximately 26 pCi m·2
s·l, plus the increased radon tesulting from further dewatering over approximately the next year,
to less than 20 pCi m·2 s-r, and
(c) the addition of approximately 2.0 feet of random fi ll cover (at 80 to 95% compaction) to the
current interim cover would reasonably be expected to be sufficient to reduce surface radon :flux
to below 20 pCi m·2 s _,, regardless of the depth of de watered tai Is.
Status of Proposed Updated Final Cover Design
As part of developing the Mill's final reclamation plan Tequired to achieve the radon flux standard of 20
pCi m·2 s·1, a final engineered cover design was submitted by TITAN Environmental in 1996 and
approved by the US NRC. An updated final cover design for the Mill's tailings system, submitted in
November 2011, is under review by DRC, and is not currently approved. DRC provided a second round
of interrogatories on the proposed cover design and associated Infiltration and Contaminant Transport
Model ("ICTM") in February 2013, for which EFRI and its consultant, MWH Inc. are preparing
responses. The proposed responses and approach to fina l cover design are the subject of a meeting
between DRC and EFRl scheduled for the last week of April 2013.
The proposed updated cover design includes the following components: from top to bottom
Letter to B. Bird
March 29, 2013
Page 8 of 15
• A 0.5 foot thick erosion protection layer consisting of gravel admixture (with no compaction
specification)
• A 3.5 foot thick water storage/bio-intrusionlfrost protection/radon attenuation l.ayer consisting of
loam to sandy clay materials at 85% compaction
• A 2.5 foot ft radon attenuation layer consisting of highly compacted loam to sandy clay, at 95%
compaction
• A 2.5 foot radoh attenuation and grading layer consisting of loam to sandy clay at approximately
80% compaction.
Proposed Action and Timeframe
Based on the foregoing analysis, and as discussed during EFRI's March 27, 2013 meeting with DAQ
and DRC staff, EFRl proposes the following in order to bring the facility into compliance:
MonitoringofCell 2
EFRI will perform monthly monitoring of radon flux at Cell 2 consistent with the requi rements of 40
CFR 61.254b. Monthly monitoring will commence in April 2013 and continue until US EPA or DAQ
determine that it is no longer required.
Construction and Monitoring of Interim Cover Test Area, and Application ofAdditional Random Fill
EFRl proposes to construct and monitor a test ... scale application to confirm the effect of the addition of
one foot of additional soil cover. EFRI proposes to apply one foot of random fill at 90% compaction to
a test area on Cell 2 of I 00 feet by 100 feet. This test area would be established on or before September
2013. The radon flux in the test area would be measured both before and after placement of the
additional till and periodically over a six month period.
If the desired reduction (to within compliance levels) is achieved on the test area, EFRI will apply one
foot of additional random fill at 90% compaction, to the remainder of Ccfl 2, on or before July 1, 2014.
EFRI will perform the 2014 annual radon tlux monitoring of Cell 2 after placement of the fill over the
entire Cell 2 area.
The foregoing proposed test and construction activities will be conditional upon DRC confirming that
such activities will not be prejudicial to or inconsistent with the final approved cover design currently
under review, and will be credited toward the final cover design.
ff you have any questions, please contact me at [phone].
;p:;t~
Energy Fuels Resources (USA) fnc.
JoAnn Tischler
Manager, Compliance and Licensing
Letter to B. 13ird
March 29,2013
Page 9 of 15
cc: David C. Frydenlund
Phil Goble, Utah DRC
Dan Hillsten
Rusty Lundberg, Utah DRC
Jay Morris, Utah DAQ
Harold R. Roberts
David E. Turk
Kathy Weinel
Director, Air and Toxics Technical Enforcement Program, Office of Enforcement, Compliance
and Environmental Justice, U.S. Environmental Protection Agency
Tables
Figures
Attachments
Letter to B. Bird
March 29,2013
Page 10 of15
Certification:
"l certify under penalty of law that I have personally examined and am familiar with the
information submitted herein and based on my inquiry of those individuals immediately
responsible for obtaining the information, T believe that the submitted information is true,
accurate, and complete. I am aware that there are significant penalties for submitting
fal info ation including the possibility of fine and imprisonment. See, 18 U.S.C.
1
David C. ·rydenlund
Senim Vice President and General Counsel
Year
2008
2009
2010
2011
2012
Table l
Year to Year Change in Radon Flux Compared to Change in SORE Water Level
for Cell2
Average l:l Water Level Jilux per ~Flux From l:l Flux*
From Year to VP.::tr Year to Year Slimes Drain
Water Level Year (ft) (pCi/m2/s) (pCi/m2/s) l:l Water Level
for the Year Negative values Negative values
(fmsl) reflect decrease in reflect decrease
water level in radon nux
5600.56 3.9
-0.397 9.8
5600.163 13.7
0.256 -0.9
5600.419 12.8
-1.005 5.2
5599.414 18
-2.104 7.8
5597.31 25.8
* Consistent negative values in this column demonstrate a consistently
inverse relationship between flux and slimes drain water level.
9.8
-0.397 =-24.7
-0.9
0.256 = -3.2
5.2
-1.005 = -5.2
7.8
-2.104 = -3 .7
Table 2
Summary of Test Pit Results
Thickness, ft Radon Flux, pCi m-2 s·'
Sampling and
Test Pit Location Dry Wet September October Cover Tailings Tailings 2012 2012 November 2012
D/G/H/I-22 3.23 11.4 4.23 20.1 18.9 36.4
D/G/H/1-25 1.17 14.71 4.16 42.9 23.8 40.8
D/G/HII-28 3.77 10.92 10.21 65.9 63.7 63.5
D/G/WI-30 5.67 10.13 11.92 70.1 48.2 57.5
D/G/H/I-48 8.88 11.13 10 1.7 2.5 2.7
D/0/H/I-85 5.77 12.98 13.82 4.1 6.8 6.8
D/0/H/I-37 2.42 17.96 5.63 44.6 34.4 43.8
D/0 /H/I-44 4.96 13.21 11.41 76.8 89.6 90.3
D/G/H/I-42 4.38 8 18.41 12.4 16.9 16.2
D/G/I-1/I-77 3.29 6.96 20.05 58.4 69.9 67.7
Average 4.35 11.74
Table 3
Cell 2 Radon Flux History -1992 to Present
Ave Flux Ave Flux Ave Flux Annual
(pCi/m2sec) (pCi/m2sec) (pCi/m2sec) Precipitation
Month Year Contractor Beach Cover Both (inches)
June 1992 Versar 12.9 7.0 9.0 12.41
Sept 1993 Tel leo 27.5 9.7 12.3 15.98
Aug 1994 Tel leo 23.3 7.7 .10.0 9.80
July 1995 Tel leo 28.4 6.1 9.5 11.12
Sept 1996 Tel leo 36.2 14.2 17.3 8.74
Sept 1997 Tel leo 41.3 7.4 12.1 16.62
July 1998 Tel leo 41.9 9.8 14.3 10.73
July 1999 Tel leo 25.7 12.4 13.3 9.44
Sept 2000 Tel leo 23.5 7.9 9.3 11.77
June 2001 Tel leo 32.2 18.2 19.4 7.66
June 2002 Tel leo 62.8 15.1 19.3 7.43
June 2003 Tel leo 71.5 13.3 14.9 8.97
June 2004 Tel leo 73.7 12.6 13.9 11.50
June 2005 Tel leo 55.8 6.6 7.1 14.76
June 2006 Tel leo 65.7 7.9 8.5 9.45
June 2007 Tel leo 50.2 13.1 13.5 11.59
June + 2008 Tel leo 3.9 12.73
June 2009 Tel leo 13.7 8.13
June 2010 Tellco 12.8 15.13
June 2011 Tellco 18.0 7.76
June 2012 Tel leo 23.1 3.1#
Sept 2012 Tel leo 26.6 6.3211
Oct 2012 Tel leo 27.7 7.9911
Nov 2012 Tellco 26.1 9.241111
Notes + F1rst year w1th no beaches exposed (all under mtenm cover)
# preciptiation as preceding month
## precipitation as of year end
SORE Slimes Drain Recovery Elevation
Feet Below Top of Standpipe
N N N ....... ....... ....... .j:>. N 0 00 0'\ .j:>.
0 0 0 0 0 0 0 0 0 0 0 0
1/30/2009
3/30/2009
5/30/2009
7/30/2009
9/30/2009 . ·~ .. . . n ~ I I u • I I I 1-11/30/2009 ()
N .:: ~ ,_..
1/31/2010 ,_..
(I) N -+ C/1 -· 3 3/31/2010 ,_..
V> §.
~ (!) ..... ~ en iO" 5/31/2010 (/) VI c N ~ '""' QJ 7/31/2010 P' ....... -· ~ :::J ~~ 9/30/2010 0 ...... N oaq
0 11/30/2010 <: E; 0 I ~ ~
\0 ~ ........ ... tr1 N !:: 1/31/2011 ,_..
::l ~ 0 (!) <: OJ
'"""'
..... 3/31/2011 a 0 Vi" ...... ... (!) 0 ..... ~ N iO" VI 5/31/2011 0 0 N
'"""'
<: ~
'"""' 7/31/2011 '"1
RO
....,
N 9/30/2011
§.
~ 0
'"""' I I } I I
111/30/2011 N
1/31/2012
3/31/2012
5/31/2012
7/31/2012
9/30/2012
11/30/2012
Figure 2
Locations of Flux Measurements and Cell 2 Test Pits
F-'l • c.=-c.--'-J ·:er: . . . . ~ ~ • ~ '1 El ~ _,
-.. u . . .
~
"r'tfTT .,., '"t
ts•avt:ltjj !l!Jft
!I'S!P\zt!!?
C Approximate
test pit
location
J'!Gf!ICJOI
~
::&a: -· ·-·-
~
~ t --.-----.-------. -------------
J'IUII
C) cover
CJ DryTailing
-WetTailing
Figure 3
Thicknesses of Wet and Dry Tailings and Cover at 10 Radon Flux Sampling Locations in Cell 2
j
Letter to B. Bird
March 29, 2013
Page 11 of 15
A TI ACHMENT 1 A
Tellco Report on Annual Radon Flux Monitoring
June 2012
National Emission Standards for Hazardous Air Pollutants
2012 Radon Flux Measurement Program
White Mesa Mill
6425 South Highway 191
Blanding, Utah 84511
June 2012 Sampling Results
Prepared for: Energy Fuels Resources (USA) Tnc.
6425 S. Highway 19 1
P.O. Box 809
Blanding, Utah 845 11
Prepared by: TeUco Environmental
P.O. Box 3987
Grand 1 unction, Co lorado 8 1502
TABLE OF CONTENTS
Page
1. INTRODUCTION ........................................................................................................................... 1
2. SITEH1STORY AND DESCRIPTION .......................................................................................... I
3. REGULATORY REQUIREMENTS FOR THE SITE .................................................................... 2
4. SAMPLTNG METf-TODO LOGY ..................................................................................................... 2
5. FIELD OPERATIONS .................................................................................................................... 3
5.~1 Equipment Preparation ....................................................................................................... 3
5.2 Sample Locations, Identification, and Placement.. ........................................................... 3
5.3 Sample Retrieval ............................................................................................................... 3
5.4 Environmental Conditions ................................................................................................ 4
6. SAMPLE ANALYSIS ..................................................................................................................... 4
6.1 Apparatus ........................................................................................................................... 4
6.2 Sample Inspection and Documentation ............................................................................. 4
6.3 Background and Sample Counting .................................................................................... 5
7. QUALITY CONTROL (QC) AND DATA VALIDATION ........................................................... 5
7.1 Sensitivity .......................................................................................................................... 5
7.2 Precision ............................................................................................................................. 6
7.3 Accuracy ............................................................................................................................ 6
7.4 Completeness ..................................................................................................................... 6
8. CALCULATIONS ........................................................................................................................... 7
9. RESULTS ........................................................................................................................................ 8
9.1 Mean Radon Flux ............................................................................................................... 8
9.2 Site Results ......................................................................................................................... 9
References .......................................................................................................................................... I 0
Figure 1 .............................................................................................................................................. II
Appendix A. Charcoal Canister Analyses Support Documents
Appendix B. Recount Data Analyses
Appendix C. Radon Flux Sample Laboratory Data, Including Blanks
Appendix D. Sample Locations Map (Figure 2)
i
1. INTRODUCTION
During June 2012, Tellco Environmental, LLC (Tellco) of Grand Junction, Colorado, provided
support to Energy Fuels Resources (USA) Inc. (Energy Fuels) regarding the required National
Emission Standards for Hazardous Air Pollutants (NESHAPs) Radon Flux Measurements. These
measurements are required of Energy Fuels to show compliance with Federal Regulations. The
standard is not an average per facility, but is an average per radon source. The standard is not an
average per facility, but is an average per radon source. The standard allows mill owners or
operators the option of either making a single set of measurements or making measurements over a
one year period (e.g., weekly, monthly, or quarterly intervals).
Tel leo was contracted to provide radon canisters, equipment, and canister placement personnel as well
as lab analysis of samples for calendar year 2012. The sampling effort commenced on June 11 , 2012.
Initially, Energy Fuels planned to make a single set of measurements to represent the calendar year
2012; the results of that set of measurements are presented in Section 9.0 of this report. However,
because the average radon flux rate measured in Cell 2 exceeded the regulatory standard, Energy
Fuels diJected Tellco to perform additional sampling in September, October, and November 2012
with the results of those samplings presented in separate reports. Energy Fuels personnel provided
support for loading and unloading charcoal ti·om the canisters. This report includes the procedures
employed by Energy Fuels and Tellco to obtain the results presented in Section 9.0 of this rep011.
2. SITE DESCRIPTION
The White Mesa Mill facility is located in San Juan County in southeastern Utah, six miles south of
Blanding, Utah. The mill began operations in 1980 for the purpose of extracting uranium a11d
vanadium from feed stocks. Processing e'ffiuents from the operation are deposited in four lined cells,
which vary in depth. Cell I , Cell 4A, and Cell4B did not require radon flux sampling, as explained in
Section 3 below.
Cell 2, which has a total area of approximately 270,624 square meters (m2), has been filled and
covered with interim cover. This cell was comprised of one region; a soil covet· of varying thickness,
which required NESHAPs radon flux monitoring. The Cell 2 cover region was the same size in 2012
as it was in 2011. There were no exposed tailings or standing liquid within Cell2.
Cell 3, which has a total area of 288,858 m2, is nearly filled with tailings sand and is undergoing pre-
closure activities. This cell was comprised of two source regions that required NESHAPs radon
monitoring: at the time of the June 20]2 radon sampling, approximately 219,054 m2 of the cell had a
soil cover of varying thickness and approximately 36,233 m2 of exposed tailings "beaches". The
remaining approximately 33,571 rn2 was covered by standing liquid in lower elevation areas. The
standing liquid area was much smaller than in 20 II. Raffinate crystals and residue from the repair of
the original Cell4A in 2006 have been placed in Cell3.
The Cell 3 cover region area was larger during the 2012 radon flux sampling than it was for the 20 J I
sampling program. Due to worker health and safety concerns by both Energy Fuels and Tellco
personnel, portions of the unstable and wet beaches and covered areas were not sampled. The areas
tested for radon emanation are representative of the disposition of tailings for the 2012 reporting
period.
1
3. REGULATORY REQUIREMENTS FOR THE SITE
Radon emissions from the uranium mill tailings at this site are regulated by the State of Utah's
Division of Radiation Control and administered by the Utah Division of Air Quality under generally
applicable standards set by the Environmental Protection Agency (EPA) for Operating Mills.
Applicable regulations are specified in 40 CFR Part 61 , Subpart W, National Emission Standards for
Radon Emissions from Operating Mill Tailings, with technical procedures in Appendix B. At present,
there are no Subpart T uranitun mill tailings at this site. These regulations are a subset of the
NESHAPs. According to subsection 61.252 Standard, (a) radon-222 emissions to ambient air from an
existing uranium mill taili ngs pile shall not exceed an average of20 picoCuries per square meter per
second (pCi/m2-s) for each pile or region. Subsection 61.253, Determining Compliance, states that:
"Compliance with the emission standard in this subpart shall be determined annually through the use
of Method 115 of Appendix B." The repair~d Cell 4A, and newly constructed Cell 48, were both
constructed after December 15, 1989 and each was constructed with Jess than 40 acres surface area.
Cell 4A and 4B comply with the requirements of 40 CFR 61.252(b), therefore no radon flux
measurements are required on either Cell 4A or 4B. Radon flux measurements were performed on
Cells 2 and 3 as discussed below.
4. SAMPLING METHODOLOGY
Radon emissions were measured using Large Area Activated Charcoal Canisters (canisters) in
conformance with 40 CFR, Part 61 , Appendix B, Method 115, Restrictions to Radon Flux
Measurements, (EPA, 2009). These are passive gas adsorption sampling devices used to determine
the flux rate of radon-222 gas from a surface. The canisters were constructed using a 1 0-inch
diameter PVC end cap containing a bed of 180 grams of activated, granular charcoal. The prepared
charcoal was placed in the canisters on a support grid on top of a Yz inch thick layer of foam and
secured with a retaining ring under 1 Yz inches of foam (see Figure 1, page 11 ).
One hundred canisters were placed in each region: one region in Cell 2 and two regions in Cell 3 as
depicted on the Sample Locations Map (see Figure 2, Appendix D). Due to worker health and safety
concerns, measurement of the wet beach areas of Cell 3 was limited to areas readily accessible by
foot. Each charged canister was placed directly onto the surface (open face down) and exposed to the
surface for 24 hours. Radon gas adsorbed onto the charcoal and the subsequent radioactive decay of
the entrained radon resulted in radioactive lead-214 and bismuth-214. These radon progeny isotopes
emit characteristic gamma photons that can be detected through gamma spectroscopy. The original
total activity of the adsorbed radon was calculated from these gamma ray measurements using
calibration factors derived from cross-calibration of standard sources containing known total
activities of radium-226 with geometry identical to the counted samples and from the principles of
radioactive decay.
After 24 hours, the exposed charcoal was transferred to a sealed plastic sample container (to prevent
radon Joss and/or further exposure during transport), identified and labeled, and transported to the
Tellco laboratory in Grand Junction, Colorado for analysis. Upon completion of on-site activities, the
field equipment was alpha and beta-gamma scanned for possible contamination resulting from
fieldwork activities. All field equipment was surveyed by Energy Fuels Radiation Safety personnel
and released for unrestricted use. Tellco personnel maintained custody of the samples from collection
through analysis.
2
5. FIELD OPERATIONS
5.1 Equipment Preparation
All charcoal was dried at I I 0°C before use in the field. Unused charcoal and recycled charcoal were
treated the same. 1 80-gram aJiquots of dried charcoal were weighed and placed in sample containers.
Proper balance operati on was verifted daily by checking a standard weight. The balance readout
agreed with the known standard weight to within ± 0.1 percent.
After acceptable balance check, empty containers were individually placed on the balance and the
scale was re-zeroed with the container on the balance. Unexposed and dried charcoal was carefully
added to the container until the readout registered 180 grams. The lid was immediately placed on the
container and sealed with plastic tape. The balance was checked for readout drift between readings.
Sealed containers with unexposed charcoal were placed individually in the shielded counting well,
with the bottom of the container centered over the detector, and the background count rate was
documented. Three five-minute background counts were conducted on ten percent of the containers,
selected at random to represent the "batch". If the background counts were too high to achieve an
acceptable lower limit of detection {LLD), the entire charcoal batch was labeled non-conforming and
recycled through the heating/drying process.
5.2 Sample Locations, Identification, and Placement
Designated sample point locations were established within each of the three regions (one region in
Cell 2 and two regions in Cell 3). A sample identification number (ID) was assigned to every sample
point, using a sequential alphanumeric system indicating the charcoal batch and physical location
within the region (e.g., 80 I ... B 1 00). This 10 was written on an adhesive label and affixed to the top
of the canister. The sample ID, date, and time of placement were recorded on the radon flux
measurements data sheets for the set of one hundred measurements.
The sampli ng locations were spread out throughout each region. Prior to placing a canister at each
sample location, the retaining ring, screen, and foam pad of each canister were removed to expose the
charcoal support grid. A pre-measured charcoal charge was selected from a batch, opened and
distributed evenly across the support grid. The canister was then reassembled and placed face down
on the surface at each sampling location. Care was exercised not to push the device into the soil
surface. The canister rim was "sealed" to the surface using a berm of local borrow material.
Five canisters (blanks) for each region were similarly processed and the canisters were kept inside an
airtight plastic bag during each 24-hour testing period.
5.3 Sample Retrieval
At the end of the 24-hour testing period, all canisters were disassembled and each sample was
individually poured through a funnel into a container. Identification numbers were transferred to the
appropriate container, which was sealed and placed in a box for transport. Retrieval date and time
3
were recorded on the same data sheets as the sample pl acement information. The blank samples were
similarly processed.
Of the 300 canisters placed throughout the three sampling regions, three samples were lost as fo llows:
• Sample B29 was lost because charcoal was inadvertently not loaded into the canister;
• Sample C86 was destroyed by heavy equipment activity after placement; and
• Sample 0 56 was lost during the loading/reloading process.
5.4 Environmental Conditions
A rain gauge and a minimum/maximum th ermometer were in place at the White Mesa Millsite to
monitor rainfall and air temperatures during sampling in order to ensure compliance with the
regul atory measurement criteria.
In accordance with 40 CFR, Part 61 , Appendix B, Method 11 5:
• Measurements were not initiated within 24 hours of rainfall.
• No rainfall occurred during any of the sampling periods.
• None of the radon measurements presented in this report were performed during
temperatures below 35°F or on frozen ground (the minimum air temperature recorded at
the site during the June 2012 collection periods was 51°F).
6. SAMPLE ANALYSIS
6.1 Apparatus
Apparatus used for the analysis:
• Single-or multi-channel pulse height analysis system, Ludlum Model 2200 with a
Teledyne 3" x 3" sodium iodide, thallium-activated (Nai(TI)) detector.
• Lead shielded counting well approximately 40 em deep with 5-cm thick lead walls and a 7-
cm thick base and 5 em thick top.
• National Institute of Standards and Technology (Nl S1) traceable aqueous solution radium-
226 absorbed onto 180 grams of activated charcoal.
• Ohaus Model C501 balance wi th 0. I -gram sensitivity.
6.2 Sample Inspection and Documentation
Once in the laboratory, the integrity of each charcoal container was verified by visual inspection of the
plastic container. Laboratory staff documented damaged or unsealed containers and verified that the
data sheet was complete.
All of the 297 sample containers and 15 blank containers received and inspected at the Tellco
analytical laboratory were verified as valid.
6.3 Background and Sample Counting
The gamma ray counting system was checked daily, including background and radium-226 source
measurements prior to and after each counting session. Based on calibration statistics, using two
sources with known radium-226 content, background and source control limits were established for
each Ludlumffeledyne counting system with shielded well (see Appendix A).
Gamma ray counting of exposed charcoal samples included the following steps:
• The length of count time was determined by the activity of the sample being analyzed,
according to a data quality objective of a minimum of 1,000 accrued counts for any given
sample.
• The sample container was centered on the Nal detector and the shielded well door was
closed.
• The sample was counted over a determined count length and then the mid-sample count
time, date, and gross counts were documented on the radon fl ux measurements data sheet
and used in the calculations.
• The above steps were repeated for each exposed charcoal sample.
• Approximately 10 percent of the containers counted were selected for recounting. These
containers were recounted within a few days foiJowing the original count.
7. QUALITYCONTROL(QC)AND DATA VALIDATION
Charcoal flux measurement QC samples included the following intra-laboratory analytical frequency
objectives:
• Blanks, 5 percent, and
• Recounts, I 0 percent
All sample data were subjected to validation protocols that included assessments of sensitivity,
precision, accuracy, and completeness. All method-required data quality objectives (EPA, 2009) were
attained.
7.1 Sensitivity
A total of fifteen blanks were analyzed by measuring the radon progeny activity in samples subjected
to all aspects of the measurement process, excepting exposure to the source region. These blank
sample measurements comprised approximately 5 percent of the field measurements. The results of
the blank sample radon flux rates ranged from 0.04 to 0.13 pCi/rn2-s, with an average of
approximately 0.09 pCi/m2-s.
5
7.2 Precision
Thirty recount measurements, distributed throughout the sample sets, were performed by replicating
analyses of individual fie ld samples (see Appendix B). These recount measurements comprised
approximately I 0 percent of the total number of samples analyzed. The precision of all recount
measurements, expressed as relative percent difference (RPD), ranged from less than 1 percent to 10.1
percent with an overall average precision of approximately 1.7 percent.
7.3 Accuracy
Accuracy of field measurements was assessed daily by counting two laboratory control samples with
known Ra-226 content. Accuracy of these lab control sample measurements, expressed as percent
bias, ranged from approximately -2.4 percent to + 1.4 percent. The arithmetic average bias of the lab
control sample measurements was approximately + I. 7 percent (see Appendix A).
7.4 Completeness
Ninety-nine samples from the Cell 3 Beach Region were veritied, representing 99 percent
completeness for that region.
Ninety-nine samples from the Cell 3 Cover Region were verified, representing 99 percent
completeness for that region.
Ninety-nine samples from the Cell 2 Cover Region were verified, representing 99 percent
completeness for that region.
Altogether, 297 samples from 300 sample locations were verified during this sampling program,
representing 99 percent completeness overall.
6
8. CALCULATIONS
Radon flux rates were calculated for charcoal collection samples using calibration factors derived
from cross-calibration to sources with known total activity with identical geometry as the charcoal
containers. A yield efficiency factor was used to calculate the total activity of the sample charcoal
containers. Individual field sample result values presented were not reduced by the results of the field
blank analyses.
In practice, radon flux ~:ates were calculated by a database computer program. The algorithms utilized
by the data base program were as follows:
Equation 8.1:
pCi Rn-222/m2sec = [Ts* A *b*~.s(di9t.7s>]
where: N =net sample count rate, cpm under220-662 keV peak
Ts = sample duration, seconds
b = instrument calibration factor, cpm per pCi; values used:
0.1708, forM-Ol/D-21 and
0.1727, forM-02/D-20
d =decay time, elapsed hours between sample mid-time and count mid-time
A =area of the canister, tn2
Equation 8.2:
Gross Sample, cpm + Background Sample,cpm
SampleCount,t ,min Background Count,t,min Error,2a = 2 X..!-------------------X Sample Concentration
Equation 8.3:
_ 2.71 + ( 4.65)(Sb}
LLD -[Ts* A *b*o.s<di9T.?S)]
where: 2. 71 = constant
4.65 =confidence interval factor
Net ,cpm
sb =standard deviation ofthe background count rate
Ts = sample duration, seconds
b = instnunent calibration factor, cpm per pCi; values used:
O.J708, for M-01/D-21 and
0.1727, for M-02/D-20
d =decay time, elapsed hours between sample mid-time and count mid-time
A =area of the canister, m2
7
9. RESULTS
9.1 Mean Radon Flux
Referencing 40 CFR, Part 61, Subpart W, Appendix B, Method I 15 -Monitoring for Radon-222
Emissions, Subsection 2.1.7 -Calculations, "the mean radon flux for each region of the pile and for
the total pile shall be calculated and reported as follows:
(a) The individual radon flux calculations shall be made as provided in Appendix A EPA
86(1). The mean radon flux for each region of the pile shall be calcul ated by summing all
individual flux measurements for the region and dividing by the total number of flux
measurements for the region.
(b) The mean radon flux for the total uranium rn ill tailings pile shall be calculated as follows:
J1A1 + ... J,Az [+] ... Ji,A;
At
Where: J5 =Mean flux for the total pile (pCi/m2-s)
J; =Mean flux measured in region i {pCi/m2-s)
Ai =Area of region i (m2)
A, =Total area of the pile (m2)"
40 CFR 61, Subpart W, Appendix B, Method 11 5, Subsection 2.1.8, Reporting states "The results of
individual flux measurements, the approximate locations on the pile, and the mean radon flux for each
region and the mean radon flux for the total stack [pile] shall be included in the emission test report. Any
condition or unusual event that occurred during the measurements that could significantly affect the results
should be reported."
9.2 Site Results
Site Specific Sample Results (reference Figure 2 and Appendix C)
(a) The mean radon flux for each regjon within the site as follows:
Cell 2-Cover Area
Cell 3 -Cover Area
-Beach Areas
-Standing Liquid
23.1 pCi/m2-s (based on 270,624 m2 area)
= 14.4 pCi/m2-s (based on 219,054 m2 area)
56.7 pCilln2-s (based on 36,233 m2 area)
= 0 pCilm2-s (based on 33,531 m2 area)
Note: Reference Appendix C of this report for the entire summary of individual measurement results.
8
(b) Using the data presented above, the calculated mean radon flux for each ceJl (pile) is, as follows:
Cell 2 = 23.1 pCi/m2 -s
(23.1)(270,624)
270,624
Cell 3 = 18.0 pCi/m2 -s
( 14.4)(219.054) + (56.7)(36,233) + (0)(33,53 1)
288,858
The weighted average radon flux rate as shown above for Cell 3 was calculated in accordance to
Subsection 2.1.3 (a) of the EPA's Method 11 5, which states "Water covered area -no
measurements required as radon flux is assumed to be zero".
As shown above, the arithmetic mean radon flux for Cell 2 at Energy Fuels White Mesa milling
facility is slightly above the NRC and EPA standard of20 pCi/m2-s, while the arithmetic mean radon
flux for Cell 3 is below said standard. The unusually dry weather which was especially severe in
2012 likely lowered the water table at the site as well as reduced the moisture content in surface
soils. It is believed that this could have increased the radon flux rates over the previous years'
reported results. Appendix C is a summary of individual measurement results, including blank sample
analysis. Sample locations are depicted on Figure 2, which is included in Appendix D. The map was
produced by Tellco.
9
References
U. S. Environmental Protection Agency, Radon Flux Measurements on Gardinier and Royster
Phosphogypsum Piles Near Tampa and Mulberry, Florida, EPA 520/5-85-029, NTIS #PB86-
16 I 87 4, January 1986.
U. S. Environmental Protection Agency, Title 40, Code of Federal Regulations, July 2011.
U. S. Nuclear Regulatory Commission, Radiological Ejjluent and Environmental Monitoring at
Uranium Mills, Regulatory Guide 4.14, April 1980.
U. S. Nuclear Regulatory Commission, Title 10, Code of Federal Regulations, Part 40, Appendix A,
January 20 12.
10
Figure 1
Large Area Activated Charcoal Canisters Diagram
11
IO·on, ci-a
PIIC EMC.ap
Appendix A
Charcoal Canister Analyses Supp01t Documents
A
ENERGY FUELS RESOURCES (USA) INC.
WHITE MESA MILL, BLANDING, UTAH
2012 NESHAPs RADON FLUX MEASUREMENTS
CELLS 2 &3
SAMPLING DATES: 6/11/12-6/14/12
SYSTEM DATE Bkg Counts (1 min. each)
I. D. #1 #2 #3
M-01/D-21 6/14/2012 143 132 137
M-01/D-21 6/14/2012 141 155 153
M-01/D-21 6/15/2012 136 127 131
M-01/D-21 6/15/2012 130 136 134
M-01/D-21 6/16/2012 132 124 132
M-01/D-21 6116/2012 137 138 139
M-01/D-21 6/14/2012 143 132 137
M-01/D-21 6/14/2012 141 155 153
M-01/D-21 6/15/2012 136 127 131
M-01/D-21 6/15/2012 130 136 134
M-01/D-21 6/16/2012 132 124 132
M-01/D-21 6/16/2012 137 138 139
M-02/D-20 6/14/2012 145 140 142
M-02/D-20 6114/2012 125 137 136
M-02/D-20 6/15/2012 148 142 133
M-02/D-20 6/15/2012 131 140 134
M-02/D-20 6/16/2012 124 125 131
M-02/D-20 6/16/2012 145 136 138
M-02/D-20 6/14/2012 145 140 142
M-02/D-20 6/14/2012 125 137 136
M-02/D-20 6/15/2012 148 142 133
M-02/D-20 6/15/2012 131 140 134
M-02/D-20 6/16/2012 124 125 131
M-02/D-20 6/16/2012 145 136 138
ACCURACY APPRAISAL TABLE
JUNE 2012 SAMPLING
Source Counts (1 min. each) AVG NET
#1 #2 #3 cpm
10146 10226 10264 10075
10216 10290 10283 10113
10351 10308 10252 10172
10412 10467 10322 10267
10317 10319 10382 10210
10336 10322 10377 10207
10091 10110 10250 10013
10143 10059 10073 9942
10106 10135 10126 9991
10105 10316 10217 10079
10134 10138 10202 10029
10122 10127 10173 10003
10232 10350 10291 10149
10505 10372 10446 10308
10405 10344 10421 10249
10506 10369 10492 10321
10214 10352 10244 10143
10286 10448 10292 10202
10263 10163 10168 10056
10322 10356 10287 10189
10270 10199 10172 10073
10191 10311 10173 10090
10144 10132 10075 9990
10179 10175 10553 10163
YIELD FOUND SOURCE
cpm/pCi pCi ID
0.1708 58985 GS-04
0.1708 59212 GS-04
0.1708 59557 GS-04
0.1708 60111 GS-04
0.1708 59778 GS-04
0.1708 59760 GS-04
0.1708 58624 GS-05
0.1708 58208 GS-05
0.1708 58495 GS-05
0.1708 59012 GS-05
0.1708 58716 GS-05
0.1708 58564 GS-05
0.1727 58765 GS-04
0.1727 59689 GS-04
0.1727 59346 GS-04
0.1727 59761 GS-04
0.1727 58734 GS-04
0.1727 59075 GS-04
0.1727 58226 GS-05
0.1727 58998 GS-05
0.1727 58325 GS-05
0.1727 58425 GS-05
0.1727 57848 GS-05
0.1727 58846 GS-05
AVERAGE PERCENT BIAS FOR ALL ANALYTICAL SESSIONS:
KNOWN %BIAS
pCi
59300 -0.5%
59300 -0.1%
59300 0.4%
59300 1.4%
59300 0.8%
59300 0.8%
59300 -1 .1%
59300 -1.8%
59300 -1.4%
59300 -0.5%
59300 -1.0%
59300 -1.2%
59300 -0.9%
59300 0.7%
59300 0.1%
59300 0.8%
59300 -1.0%
59300 -0.4%
59300 -1.8%
59300 -0.5%
59300 -1.6%
59300 -1.5%
59300 -2.4%
59300 -0.8%
-0.6%
R·e.
Po f.-+
f~c r('s~·
f ,'e
~{,....-
CHARCOAL CANISTFR ANALYSIS SYSTEM
SITE LOCATION: Vf h i·h M. -l-6&\ JA I t f,_"B.l""-Y-1 d ·, V\j ~ "T.L._ __
cLIENT: 'De""'l se>..-. ~lvt.t.~ (us AL (o...-f---------
Cnlibration Check Log
Systcm JD: M-0 2/D -:;)...0 CnlibrationDate:. t1 (09/r2.. Due Date: ~Jocp/!.3
0 I
Scaler SIN: 5'/ t;;" {p 3 Hi gh Voltage:_ e 2 <-;' Window: 4.42 Thrshld: 2.20
Detector SIN: 0 L/-1 S-3 ;;:L Sourtc ID/SN: 'Rt\ 21--~~ G S -o'-f Source Activity: S '1·· 3 l<f-C
Bl k c . Bk d I' 2 1., 11 I C:;L 3rt.-. 11 -1 to 15 a an amster g . ,angc, cpm: 0" == _ _!-_1 ___ to _;_.::;..J____ v 1 .....:..::::::......~...J'----
Gross Source Range, cpm: 2 cr = I 0'2 I I t<> I 0 (po5 3 cr == I 0 I\ 3 to I D 7 f!:t_
Technician: .Y-;2 ~------
All counts times are one minute
Date By Backl!round Counts (I min. c11ch) Source Counts (1 min. each) ok?
#1 #2 #3 Avg. #I #2 #3 Average YIN
&/1'-f In-lZt.."D,-l 4s-\t4 o \,4 ..,_ I I L.{ '?-10232 t03S"'O t 0 '.)..0) , I 010 I '" &/1t..//r1... Pl GI!JW)1. \'<.~ 1'31 13 " 13 .3 I D -;-o s-I 0 37'2 .. \Ot.~ tJ (o i O'f'f I 'y
(pf,.,. n~ 1/j.{~>j,yl. F4''B \4"2-,·2,·~ I '11 1 o'+o s 1 0~~ l0 li2.J 10 3C,O ..:..;
(p/1'5/ /~ ~_torr--' 3t 140 -WI-· 135" /OSOI(J t 0"301 t ol-t V'l-:2.. ID'-1-S-(p Y'
lP//~p In-l:t-~ 12.4-\?..> 1?-7 1 0?-14 t o ·~5::2-{ 0 2-4t.l 1 0 "2.70 'I
w/t~ 1 r2. lA:ar~ t4S 130 1313 ! 140 ro :z-Bb 1 O'flf'8 I 0'2.!.7) ·-z.. {03 ~;}... 'y
l
I
' i
-· I
I
I :
,,
YIN: Y = avewgc backgrou nd and source cpm falls with 11 the control iimits.
N =average backgr()und and source cpn' docs not 1:111 within the control limits.
The acceptable ranges wer•! determin.:d fn1m p ior backg ou nd and source check data.
p.~e
'?o!,+.
fh~
'fb~-t
'fre
Post
CHARCOAL CANISTER ANALYSIS SYSTEM
SITELOCATION: W ~: t-e 1--'\e~P~ fv\.·;t( 1 tsi~VIcl~VV)-, LA T
CLIENT: ~<?-vdso"" t"'li·V\es {t.~~.5A} CorP-~· _______ _
Calibration Check Log
W\ -0 J-j 'l) -.:2-0 System ID: .. ____ ..!......_ _____ _ Calibration Date: W /09 J I .:2.. Due Date: (p / D<:j_L _t=3'---
Scaler SIN: __ __;;:-~:..:;__!_S_-_,_~_3 __ f)-:~ '5' High Voltage: ~ Window: 4.42 Thrshld: 2.20
Detector SIN: _...JO""-' _4-'----t .;;..5_,3::;__L.~ o 2-Z.·~ !tG r-tJC"" Source ID/SN: K..~ (l:l:;:; :_:;, Source Activity: 5''1 •· ~ ktl>c_;
Blank Canister Bkgd. Range, cpm: 2 cr = 1'2-:l__ to IS'J.-. 3 cr= IIJ to 159
Gross Source Range, cpm: 2cr= l<O 0 '3 ) to I 0 ~f..t; 7 3 cr = q$72 to t o3·z.y,
Technician: ---~~~L:.,__;:L::.__...:::~:::::..lol-4c==::=----
All counts times are one minute
Date By Background Counts (1 min. each) Source Counts() min. each) ok?
#l #2 #3 Avg. tfl #2 #3 Average YIN
I!.>/ 14 /r1.-ouc--.. 14~ 140 I LJ. -z. I Lf 'J. 10'2(i~ lo(~~ IOit,B I o 10'6 y
I &/1'-1 I,.,_ '9l-~ }'\. 125" \37 l~fn I '2,·3 1 o·~2"l-I o '3<;-(D lo.:2:R7 I 0 3 -:2-::z.-'y,'
lfv/t')/IZ.. ltfL.4.t : ..... lt..\ P> 142. 1'.3 ~ 141 1'0"2 7'0 loiC)O! 101'72 I 0 2-ll/ ~i
fv/1)/1 ~ ~I-to~ 13( 140 134 13~ lOr~ I I 0'3 II t '01'/~ I 0::Z...2..<5" y
(pft wh .,_ ~i:>w.. t ·Lt..f-\ ?.s-\31 \';;)..7 lol4~ J0\~2. 10o'7.~ tOll 7 y
iP/IW/1'?-b.lt?iM 1'75 \ ·~t, /'3 ~ .14'0 10\~10 \0 I ·7 :5" t oc.:;-c:: =? 10~ 0 ':2-'I
YIN: Y =average background and source cpm Iiliis within the control limits.
N =average background and source cpm docs not tall within the control limits.
The acceptable ranges were detennined from prior background and source check data.
R~
Pv~t­
t?•-e. Fb<..r
Pre..
rost
CHARCOAL CANISTER ANALYSIS SYSTEM
SITE LOCATION: w (!) 7+r:= M e.~q 1Vl·.ll ,_151 ~if\ _d ~ Vl3-.J'--=LA.LT.L__ __ _
CLIENT: \:)-eN\ 'ISGV\ tv\\ vtf_.~ (~If) Co rf--· ----------
Calibration Check Log
System ID: _.!..tv1..!...--0_I--=-./_o_~_2----'-l ___ Calibration Date: &> / 0~ }1 2 ... Due Date: & / 0<1 /I "3
ScalerS/N: __ .=5:::...-_.1::::-S:.........:.7_"-____ High Voltage: 11?-S' Window: 4.42 Thrshld: 2.20
Detector SIN: -~()::....4..J.....:_l.:::.5-:.3~·~L.._--Source 10/SN: ~ l" "l. <Joj G S ~ 0~ Source. Activity: .5Y.-3 K~C.:
Blank Canister Bkgd. Range, cpm: 2 cr = _1_1 ~-·-to IS 'B 3 cr = 110 to lfo7 ~--
Gross Source Range, cpm: 2 (J = I D oq ~ to I ot.f B I 3 (J = _Of.!....OJ~<i._!:B:.__ to I DS7 B
Technician: y ·Z-~-------
All counts times are one minute
Date By Background Counts (1 min. each) Source Counts (1 min. each) ok?
#1 #2 #3 Avf!.. #1 #2 #3 Average YIN
(pf;L{/0-!17~·~ \ '-l ~ 1~?-1~/ I '31 0 lq~ 1 o-227;; f(f2/;,4 1 o-:z .. t-z... y
&/t'-J/t2-~.i"Ctr J l.,f I ft::: '<' ih 3 150 r0-..21 (.., 11)-2•?) 0 )Cf2_1~:y1 j(),;?-(.;,3 'Y
(v/1 ~,,...,.._ ~~-:y-f3G I').... I \~) 13/ o-;;~·, I 030R 1-n "2 c::--2 I 030'1 y
(pj,")/]1-lvlto~' ~130 ''A.,(i, 134: \3'3 o tf 1·'J-lO t.J ~.n-1 \0 3::2.:2-10'-fOO y
(f,fi&J 1"7-VU.c.,-\'32-1~4-t '37-1'20 l0"?-.11 to ·~ ,o.; 1 o?Jf5: i0'3"3G) y
c., /tw J 1'J..-11/LC~t.YV 1":10 1-s~ 130) /'38 lO "3'3~ J032.:2 .. 10"2.77 I 03'4 c;-y
YIN: Y =average background and source cpm 1alls within the control limits.
N =average background and source cpm does not Jail within. the control limits.
The acceptable ranges were determined from prior b<~ckground and source check data.
P.--<. f't:~Jf
Pr-e
POSt
f.~e
r~·r
CHARCOAL C/\NlSTER ANALYSTS SYSTEM
SITELOCATION: \tJb',-te Me..£P\ f"'\'~\\)·J3j"'VIJ~vt~-J ~,..J...T-'-----
CLIENT: 12 .e-""-\ YV h tv'\~ V\.€..$ ( 4 5 A) CD rf,
CalibratiOI) Check Log
System ID: rY'I·-0 I / D -:2. \ Calibration Date: Due Date: ~~ 09 J 13
Scaler SIN: ~-{ S1 ;)_ High Voltage:_ \I "2.-'5 Window: 4.42 Thrshld: 2.20
u () 1-'1--Y/ r-s-vr:-(;:-Detector SIN: 0 ~ 1.50 "3 Source £0/SN: "'&'\ I u ., .:::> Source Activity: .Jq • "3k.fCi
Blank Canister Bkgd. Range, cpm: 2 cp= I \ <1 to I S 8 3 a =-··-I I 0 to / (p]
Gross Source Range, cpm: 2 a "' I 0 05'9 to _I q'-+2-.3 __ 3 a == 90J b 'l3 to I D~ {if
Technician: 'P~ a::t.~Jv.~-----
All counts times are one minute
Date By Background Counts (I miJl. cacll) Source Counts(I min. each) ok?
#1 112 #3 Avf!.. #l #2 #3 Average YIN
~/J'-//12 117'.L.v:J. 14? l12 1~7 13'1 \ n nO\\ ~01 \0 1-n?<:::-0 101~0 'l
IC,/ I 't I I 7-B'l4t,;L. , I 4-\ . .:::-.:;-ts-3 tS'O l014 3 I 0 oc:;-q 1 oo· ... r:? 1 ooqd-Y'
1&/iS/J-:>-11/h:.,/t.. l3U. l2.1 \11 i31 !OtOv1 -,~51~ fn1z~ I D I J...-:l-y
~/IS/ j:l-IPLto~ \5D l '7, i. ,..,u. -I 3,3 1010.<\ , li -~~~"" I 1)""> 14 /D;;J..t 3 y·
C,/ll,o/t'J-l)t lot¥--1"3 '2-. t?J.I-f-~i 1?-q I o I':?,'~ (r> 1 ·7. P> ln2n-::2.. iOl~ 8 '{
{pf/tp /1:).. V.tictl" I 3 ·7 136 /30) 13f3 t r") ,.;2--2. l n-1 ·'2/ \ ot·13 I o 1'-fJ y
i
!
YIN: Y =average background and source cpu1 f.11ls within the control limits.
N =average background and source cpm does not !'all within the control limits.
The acceptable ranges were determined from p:·ior background and source check data.
Appendix B
Recount Data Analyses
B
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: B SURFACE: TAILINGS
AREA: BEACH DEPLOYED: 6 11 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21 , M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 64oF
12 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
145 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD PRECISION
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s % RPD
BlO
RECOUNT
B20
RECOUNT
B30
RECOUNT
B40
RECOUNT
B50
RECOUNT
B60
RECOUNT
B70
RECOUNT
B80
RECOUNT
B90
RECOUNT
BlOO
RECOUNT
Bl O
BlO
B20
B20
B3 0
B30
B4 0
B4 0
B50
~50
B60
B60
B70
B70
B80
B80
B90
B90
BlOO
BlOO
8 28 8 35 6 15 12 10 27
8 28 8 35 6 16 12 10 30
8 36 8 40 6 15 12 10 34
8 36 8 40 6 16 12 1 0 30
8 43 8 49 6 15 12 10 41
8 43 8 49 6 16 12 10 31
8 51 8 55 6 15 1 2 10 48
8 51 8 55 6 1 6 1 2 10 31
8 51 9 2 6 15 12 10 56
8 51 9 2 6 1 6 12 10 33
9 0 8 51 6 15 12 11 5
9 0 8 51 6 16 12 10 33
8 53 8 4 6 6 15 12 11 11
8 53 8 46 6 16 12 10 34
8 41 8 3 9 6 15 12 11 18
8 41 8 39 6 16 12 10 34
8 29 8 35 6 15 12 11 25
8 29 8 35 6 16 12 10 36 ----
8 1 8 8 30 6 15 12 11 33
8 1 8 8 30 6 16 12 10 36
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
35248 2J.2.3
29325 2J.2.3
9146 214 .8
7747 214.8
19428 217 .6
15690 217.6
20838 215.6
17515 215.6
37413 216.4
30719 216 .4
10711 215.3
9122 215.3
15162 211.1
12454 211.1
17421 214.7
14972 214.7
17797 220.3
15149 220.3
21728 211.1
18651 211.1
85.2
84.9
21.9
22.2
46.8
45.2
50.3
50.5
90.2
88 .5
26.0
26.3
36.9
36.1
42 .4
43 .4
43 .2
43 .7
52 .7
53 .8
8 .5
8.5
2 .2
2 .2
4.7
4 .5
5 .0
5 .1
9.0
8 .8
2 .6
2 .6
3 .7
3 .6
4.2
4.3
4.3
4 .4
5 .3
5 .4
0 .04
0.05
0 .04
0 .05
0.04
0.05
0 .04
0 .05
0 .04
0.05
0 .04
0 .05
0.04
0 .05
0 .04
0.05
0 .04
0.05
0 .04
0.05
0.3%
1.2%
3.5%
0 .4%
2 .0%
1.4%
2.2%
2 .3%
1.3%
2.0%
AVERAGE PERCENT PRECISION FOR THE CELL 3 BEACH REGION: 1 .7%
Page 1 of 1
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: C SURFACE: TAILINGS
AREA:COVER DEPLOYED: 6 12 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21 , M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 51°F
13 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
143 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE RETRIV ANALYSIS MID-TH1E CNT GROSS GROSS RADON ± LLD PRECISION
LOCATION I. D. HR MIN HR l.UN MO DA YR HR MIN (l.UN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s % RPD
C10
RECOUNT
C20
RECOUNT
C30
RECOUNT
C40
RECOUNT
cso
RECOUNT
C60
RECOUNT
C70
RECOUNT
C80
RECOUNT
C90
RECOUNT
C100
RECOUNT
C10
C10
C20
C20
C30
C30
C40
C40
cso
cso
C60
C60
C70
C70
C80
C80
C90
C90
C100
C100
9 3 6 9 so 6 15 12 8 44
9 36 9 so 6 16 12 10 15
9 3 3 9 4 9 6 15 12 8 54
9 33 9 49 6 16 12 10 12
9 49 9 57 6 15 12 9 2
9 49 9 57 6 16 12 10 18
9 49 9 57 6 15 12 9 10
9 49 9 57 6 16 12 10 19
10 4 10 6 6 .15 12 9 19
10 4 10 6 6 1 6 12 10 21
10 6 10 6 6 15 12 9 27
10 6 10 6 6 16 12 10 21
10-15 10 18 6 15 12 9 36
10 15 10 18 6 16 12 10 22
10 25 10 24 6 15 12 9 54
10 25 10 24 6 16 12 10 22
10 28 10 26 6 15 12 10 4
10 28 10 26 6 16 12 10 24
10 26 10 29 6 15 12 10 11
10 26 10 29 6 16 12 10 25
4
4
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
2
2
1189 223.2
1129 223 .2
6508 212.1
5426 212.1
1997 211.3
1659 211.3
1049 216.8
1773 216.8
5154 211.5
4232 211 .5
34642 209.5
29055 209 .5
40407 213.8
33132 213.8
1927 218.4
1640 218.4
2559 212.1
2026 212.1
1189 209.8
1022 209.8
0 .30
0 .34
12 .5
12.6
3.7
3.7
1.8
1.8
10.0
9.9
68 .8
69.6
80.1
80.1
3.6
3 .6
4.8
4.6
0.9
0.9
0.0
0 .0
1.3
1.3
0.4
0.4
0.2
0.2
1.0
1.0
6.9
7 .0
8.0
8.0
0.4
0.4
0.5
0.5
0.1
0.1
0.04
0 .04
0.04
0.04
0.04
0.04
0.04
0.04
0 .04
0.04
0.04
0.04
0.04
0.04
0.04
0 .04
0 .04
0.04
0 .04
0.04
10.1%
0 .5%
0.1%
0.8%
0 .3%
1 .1%
0.1%
0.9%
5.4%
2.1%
AVERAGE PERCENT PRECISION FOR THE CELL 3 COVER REGION: 2.2%
Page 1 of 1
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: D SURFACE: TAILINGS
AREA:COVER DEPLOYED: 6 13 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 56°F
14 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
146 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD PRECISION
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN} COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s % RPD
010
RECOUNT
D20
RECOUNT
030
RECOUNT
040
RECOUNT
050
RECOUNT
D60
RECOUNT
070
RECOUNT
080
RECOUNT
090
RECOUNT
0100
RECOUNT
010
010
020
020
030
030
040
040
050
050
060
060
070
070
080
080
090
090
0100
0100
10 56 11 1 6 15 12 13 1
10 56 11 1 6 16 12 9 55
11 14 11 6 6 15 12 13 9
11 14 11 6 6 16 12 9 55
10 56 11 1 6 15 12 13 19
10 56 11 1 6 16 12 9 57
11 14 11 6 6 15 12 13 26
11 14 11 6 6 16 12 9 57
11 24 11 11 6 15 12 13 34
11 24 11 11 6 16 12 10 1
11 37 11 39 6 15 12 13 41
11 37 11 39 6 1 6 12 10 1
11 24 11 11 6 15 12 13 51
11 24 11 11 6 16 12 10 3
11 39 11 41 6 15 12 14 3
11 39 11 41 6 16 12 10 4
11 42 11 42 6 15 12 14 12
11 42 11 42 6 16 12 10 9
11 45
11 45
11 47
11 47
6 15 12
6 16 12
14
10
21
8
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
3
3
2
2
27215 214.7
23094 214.7
10431 209.4
9206 209 .4
41445 207.6
35280 207.6
24972 209.7
22148 209.7
8093 212.6
68J.8 212.6
2110 214.0
1824 214 .0
6425 209.9
5395 209.9
1506 212.7
1326 212 .7
1430 210 .1
1289 210 .1
1401 210.2
1289 210.2
45.8
46.0
1 7.6
18 .1
70.1
70 .... 4...__
42.5
44 .0
13 .7
13.5
3.3
3.3
10 .8
10.6
1.0
1.0
0 .57
0.58
1.0
1.0
4.6
4.6
1.8
1.8
7.0
7.0
4.3
4.4
1.4
1.4
0.3
0.3
1.1
1.1
0.1
0.1
0.1
0.1
0.1
0.1
0.03
0.04
0.03
0 .04
0.03
0.04
0.03
0 .04
0.03
0 .04
0.03
0 .04
0 .03
0.04
0.03
0 .04
0.03
0.04
0.03
0 .04
AVERAGE PERCENT PRECISION FOR THE CELL 2 COVER REGION:
Page 1 of 1
0.4%
2.8%
0.4%
3.5%
1.5%
0 .0%
1.9%
0.0%
1.7%
0 .0%
1.2%
Appendix C
Radon Flux Sample Laboratory Data (including Blanks)
c
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: B SURFACE: TAILINGS
AREA: BEACH DEPLOYED: 6 11 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC.TE.DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 64°F
12 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
145 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
B01
B02
B03
B04
B05
B'01 8 20 8 31 6 15 12' 10 20 1 24811 2.12.4 60.3 6.0 0.04
B02 8 21 8 31 6 15 12 i.O 20 1 5·9916 215.2 144.7 14 .5. 0 .04 ----. .. ---... _, --~ B03 8 22 8 32 6 15 12 10 21 1 36591 21 7.9 89.2 8.9 0 .04
B04 8 23 8 32 6 15 12 10 21 1 29086 222.5 70 .1 7.0 0.04
BOS 8 24 8 33 6 15 12 10-23 n 1 49SOO 2l 7 :--7 -l 2l .7 12.2 0.04
B06 8 24 8 33 6 15 12 10 23. 1 284'88 22'1.0 68.7 6.9 0.04 ------~ -..... _.........., ----------------B07 B07 8 25 8 34 6 15 12 10 25 1 25124 218 .7 61.2 6.1 0 .04
B08 B08 8 26 8 34 6 15 12 10 25 1 21862 212.3 52.7 5 .3 0.04
B09 ---B09 8 27-8 ~3s-6 is 12 10 27 1 38~21 2 09.2 94.4 9.4 0 .04
1no s1o 8 28 8 35 6 15 12 10 27 1 35248 212.3 85.2 8.5 o.o4 ~~ -.-:.:~-.-; ~-11011!-......-..: ;,o -....... _ ---..,;;;..;_ --·.----
B11 B11 8 28 8 36 6 15 12 10 28 1 21653 216.4 52.7 5.3 0.04
B12 B12 8 29 8 36 6 15 12 10 28 1 58528 214.4 141.7 14 .2 0.04
B13 ---· B1-3 -n 8 30 8 37 n61s 1"2 10 -30 1 3~0S18~~-~ 74.5 ---7-.5--·0 .04
B14 B14 8 31 8 37 6 15 1.2 10 30 1 389'97 210 .8 . 94.4 9.4 0.04 .. . ----::;;_ _.,;..:,:. -...... ----B15 B15 8 32 8 38 6 15 12 10 31 1 32615 208 .9 79 .7 8.0 0.04
B16 B16 8 32 8 38 6 15 12 10 31 1 27337 215.3 66.0 6.6 0.04
B~17 ---B17 8 33 8 -39 -6 -15 l 2 -10 33 -1 283 1,0 211.0 n 69.'2. --6.9 ' 0.04
B18 , B18 8 34 8 · 3·9 6 15 12 10 33 1 45398 209.6 110 .. 0 11.0 0.04 . . -~ ....:: ..,_. --...-; --. .. _.. ----~ _.._ ... -B19 B19 8 35 8 40 6 15 12 10 34 1 14913 215.6 36.3 3.6 0.04
B20 B20 8 36 8 40 6 1 5 12 1 0 34 1 9146 214.8 21 .9 2.2 0.04
B21 --B2.1 8 3 6 8 41 -6 -15 ·12 10~ 36 --T --42092 2D .5·--103.1 r 10.3 --a .o4 _____ _
B22 __ B2? ___ 8 _37 8 41 6 15 1~ 12.._ 36 1 }7d47 215.2 65 . ..!_ _ 6._5 0 .. 0.!.,
B23 B23 8 38 8 42 6 15 12 10 37 1 10440 215.9 25.3 2.5 0.04
B24 B24 8 39 8 42 6 15 12 10 37 1 25543 213.6 61.8 6.2 0 .04
B25 ~-B25 8 39 8' .ll3--6-15 l 2 10 39 -1 -26350 212.7 64."5 -~ 6.4--0.04
B26 __ ~~6 ~ _ .8 ~1.2_~-4 1. _ 6~ 15 12 !_0 39 1 __ 23564~~ 2].2. 2 _§.6.: 8 _ 5. 7 9. 04 ~-~----..J
B27 B27 8 41 8 48 6 15 12 10 40 1 54969 215.7 134 .5 13 .5 0.04
B28 B28 8 42 8 48 6 15 12 10 40 1 25210 212.2 60.9 6.1 0.04
B29 -~ B29 8 43 8~ -4n9 ------ ----
_....__ B·~O .-. §_ 43~ 8 .49 6 15 12 l (L_. 41
B31 8 44 8 50 6 15 12 10 43
B32 B32 8 45 8 51 6 15 12 10 43
B33 -·--~B;33 8 '46 8 -s i 6 15-12 10 44
B34 B34 8 46 8 52 6 15 12 10 44 '-=-~~· ~" -"-
1
1
1
1
1
Page 1 of 3
1942?_ 217.(i 46.8 -
21490 215.2 52.4
43840 218.6 106.1
2i382 219.2 -57.1
2_578~ 214.8 62.3
4. 7 0. 04
5.2 0.04
10.6 0.04
5 ~7 -0.04
6.2 0.04
SAMPLE LOST
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS. WHITE MESA MILL
PILE: 3 BATCH: B SURFACE: TAILINGS
AREA: BEACH DEPLOYED: 6 11 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 64"F
12 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
145 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN {MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
B35
B36
B37
B38
B39
B40
B41
B42
B43
B44
B45
B46
B47
B48
B49
B50
B51
B52
B53
B54
B55
B56
B57
B58
B59
B60
B61
B62
B63
B64
B65
B66
B67
B68
B35 8 47 8 52
B36 8 48 8 53
B37 8 48 8 53
B38 • 8 49 8 54
B39 8 50 8 55
B40 8 51 8 55
B41 8 51 8 56
B42 8 52 8 57
B43 8 53 8 57
B44 8 54 8 58
B45 8 55 8 59
B46 8 55 8 59
B47 8 54 9 0
B48 8 53 9 1
B49 8 52 9 1
B50 8 51 9 2
B51 8 51 8 56
B52 8 52 8 55
B53 8 53 8 54
B54 8 54 8 54
B55 8 55 8 53
B56 8 56 8 53
B57 8 57 8 52
B58 8 58 8 52
B59 8 59 8 51
B60 9 0 8 51
B61 ~ 9 1 8 50
B62 9 2 8 50
B63 9 1 8 49
B64 9 0 8 49
B65 8 59 8 48
B66 8 57 8 48
B67 8 56 8 47
B68 8 55 8 47
6 15 12 10
6 15 12 10
6 15 12 10
6 15 ~12 10
6 15 12 10
6 15 12 10
6 1s 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10 --6 15 12 10
6 15 12 10
6 15 12 10
6 _!!?_12 10
6 15 12 11
6 15 12 11
6 15 12 11
6 15 12 11
6 15 12 11
6 15 12 11
6 15 12 11
6 15 12 11
6 1 5 12 11
6 15 12 11
6 15 12 11
6_15 -;1..2 11
6 15 12 11
6 15 12 11
45
45
47
47
48
48
50
50
51
51
53
53
54
54
56
56
58
58
59
59
1
1
3
2
5
5
6
6
7
7
9
9
10
10
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
Page 2 of 3
23725
19009
31588
20170
19856
20838
16452
26027
8177
5329
29579
27282
28895
25614
64714
37413
21883
17529
8887
9976
54678
3994
1301
1454
4858
10711
4661
12164
23957
10254
12340
62525
14011
9860
217.3
21 4.8
214.3
216.3
217 .1
215 .6
215.9
210.0
218 .1
218.8
216 .8
216.1
212.6
216.9
216 .8
216 .4
210.8
209.9
210 .7
211.7
213.3
213 .1
215.6
222.3
213.7
215.3
216.2
214 .5
218.5
217.1
217.0
217.4
213 .6
218.7
57 .9
45 .8
77.3
48.7
48 .4
50.3
40.1
62.9
19.8
12.6
72 .4
~6.:.2.
70.6
61.8
158.3
90.2
53.5
42.4
21.6
f 4.0
134.8
9.4
1.3
3.2
11 .7
26 .0
11.2
29.6
59 .3
24 .9
30.4
153 .5
34 .5
23.9
5.8
4.6
7.7
4.9
4.8
5.0
4.0
6.3
2.0
1.3
7.2
6.6
7 .1
6.2
15 .8
9.0
5.3
4.2
2.2
2 .4
13.5
0.9
0.1
0 .3
1.2
2.6
1.1
3 .0
5 .9
2.5
3 .0
15.3
3.5
2.4
0 .04
0 .04
0.04
0.04
0 .04
0 .04
0.04
0.04
0 .04
0 .04
0.04
0.04
0.04
0 .04
0.04
0.04
0.04
0 .04
0.04
0.04
0.04
0.04
0.04
0 .04
0 .04
0.04
0 .04
0.04
0.04
0.04
0.04
0 .04
0.04
0 .04
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: B SURFACE: TAILINGS
AREA: BEACH DEPLOYED: 6 11 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 64°F
12 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
145 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
8100
869
87Q.
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
8100
8 54 8
~ 53 8
8 52 8
8 50 8
8 49 8
8 48 8
8 47 8
8 46 8
8 45 8
8 43 8
8 42 8
8 41 8
8 40 8
8 39 8
8 38 8
8 36 8
8 35 8
8 34 8
8 33 8
8 32 8
8 31 8
8 29 8
8 28 8
8 27 8
8 26 8
8 25 8
8 24 8
8 22 8
8 21 8
8 20 8
8 19 8
8 18 8
46 6 15 12 11
46 6 15 12 11
45 6 15 12 11
45 6 15 12 11
44 6 15 12 11
44 6 1,5_ 12 11
41 6 15 12 11
40 6 15 1 2 11
40 6 15 12 11
40 6 15 12 11
39 6 15 12 11
39 6 15 12 11
38 6 15 12 11
38 6 15 12 11
38 6 15 12 11
37 6 15 12 11
37 6 15 12 11
36 6 15 12 11 ---36 6 15 12 11
36 6 15 12 11
35 6 15 12 11
35 6 15 12 11
35 6 15 12 11
34 6 15 12 11
34 6 15 12 11
33 6 l~ 12 11
33 6 15 12 11
32 6 15 12 11
32 6 15 12 11
31 6 1 5 12 11 ---31 6 15 12 11
30 6 15 12 11
11
11
13
13
14
14
15
15
17
17
18
18
19
19
21
21
22
22
24
24
25
25
27
27
28
28
30
30
31
31
33
33
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
27046
15162
1627
13116
12725
;t 7591
13077
10898
18 289
13486
5586
17421
14996
24116
20122
24441
12 939
15149
17519
35645
20725
17797
19445
9201
4210
17791
36638
29209
38405
24727
21431
21728
210.9
211.1
216.0
219.9
213.4
213.3
211.7
216.2
215 .8
215.9
216.8
214.7
216.4
211.2
218.9
211 .1
212 .2
213.3
211.0
211 .7
216.2
220.3
215.6
211.1
216.0
216.1
213.5
210.1
214.2
210.7
211.2
211 .1
AVERAGE RADON FLUX RATE FOR THE CELL 3 BEACH REGION :
Page 3 of 3
66.9
36 .9
3 .7
31.9
31.3
42 .8
32 .2
26.5
45 .1
32 .8
13.5
42.4
36.9
58.8
49.6
59.6
31-:7
36.8
4 3 .0
86 .9
51.0
43 .2
47.7
22.1
10.0
43.1
90.2
71.0
94 :4
60 .0
52 .5
52 .7
6.7
3.7
0.4
3.2
3.1
4 .3
3.2
2.6
4.5
3.3
1.4
4.2
3.7
5.9
5.0
6.0
3.2
3.7
4 .3
8.7
5.1
4 .3
4.8
2.2
1.0
4.3
9.0
7.1
9.4
6 .0
5.3
5.3
56 .7 pCi/m2 s
0.04
0.04
0.04
0.04
0.04
0.04
0 .04
0.04
0.04
0 .04
0.04
0.04
0.04
0.04
0.04
0 .04
0 .04
0 .04
0 .04
0 .04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0 .04
0.04
0 .04
0.04
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: C SURFACE: TAILINGS
AREA: COVER DEPLOYED: 6 12 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM 1.0.: M01 /D21, M02/D20 CAL DUE: 6/10/13
AIR TEMP MIN: 51 oF
13 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
143 cpm WI. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
COl
C02
C03
C04
cos
C06
C07
cos
C09
ClO
Cll
C12
C13
C14
ClS
C16
C17
C18
C19
C20
C21
C22
C23
C24
C25
C26
C27
C28
C29
C30
C31
C32
C33
C34
COl
C02
C03
C04
cos
C06
C07
cos
C09
ClO
Cll
C12
C13
C14
C15
C16
C17
ClS
C19
C20
C21
C22
C23
C24
C25
C26
C27
C28
C29
C30
C31
C32
C33
C34
9 23
9 24
9 26
9 27
9 29
9 30
9 32
9 33
9 35
9 36
9 38
9 39
9 23
9 24
9 26
9 27
9 29
9 30
9 32
9 33
9 35
9 36
9 38
9 39
9 42
9 43
9 45
9 46
9 48
2-. 4 9
9 51
9 53
9 54
9 56
9 43 6 15 12 8
9 44 6 15_].2 8
9 45 6 15 12 8
9 46 6 15 12 8
9 47 6 15 12 8
9 47 6 1_5 12 8
9 48 6 15 12 8
9 49 6 15 12 8
9 50 6 15 12 8
9 50 6 l2._12 8
9 51 6 15 12 8
9 52 6 15 12 8
9 43 6 15 ~ l2 8
9 44 6 15 12 8 ---9 45 6 15 12 8
9 46 6 15 12 8
9 47 6 15 12 8
9 47 6 J.~_p 8
9 48 6 15 12 8
9 49 6 15 12 8
9 50 6 15~ 12 8
9 50 6_15 12 8
9 51 6 15 12 8
9 52 6 15 12 8
9 53 6 15 12 9
9 54 6 ~5 12 9
9 55 6 15 12 9
9 55 6 15 12 9
9 56 6 15 12 9
9 57 6 8... 12 9
9 57 6 15 12 9
9 58 6 15 12 9
9 ss 6 1s 12 9
9 59 6 15 12 9
32
32
34
34
36
36
39
39
41
44
47
47
48
48
50
50
51
52
54
54
56
55
58
58
0
0
1
1
2
2
4
4
5
5
1
1
1
1
1
1
1
1
1
4
1
1
1
1
1
1
1
2
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
Page 1 of 3
1390
2587
5111
6996
8643
26269
2178
30876
2403
_1189
4538
18385
2685
4876
18753
1077
1073
1155
1504
6508
1508
14021
1125
1896
35664
1041
1100
11387
4502
1997
9288
9999
12528
14566
212.4
214.1
211.8
210.5
211.4
215.2
211.7
213.0
212.7
223.2
212.1
214.4
211.1
212.1
211.7
212.2
211.3
212.1
211.7
212.1
211.5
211.0
214.3
222.6
212.4
219.9
218.2
216.6
215.4
211.3
212.1
226.2
212.2
211.1
2.5
4.8
9.9
13.5
16 .9
51.4
4.0
60.5
4.5
0.3
8.8
36 .0
5.1
9.3
37.0
1.8
1.9
0.9
2.7
12 .5
1.2
21 .4
2.0
3 .5
71.0
1.~
1.9
22.3
8.7
3 .7
18.3
19.6
24.9
28.7
0.2
0.5
1.0
1.3
1.7
5.1
0.4
6.0
0.4
0.0
0.9
3.6
0.5
0.9
3.7
0.2
0.2
0.1
0.3
1.3
0.1
2.7
0.2
0.3
7.1
0.2
0.2
2.2
0.9
0.4
1.8
2.0
2.5
2.9
0.04
0 .04
0.04
0.04
0.04
0.04
0 .04
0.04
0.04
0.04
0.04
0 .04
0.04
0.04
0 .04
0 .04
0.04
0.04
0.04
0.04
0.04
0.04
0 .04
0.04
0.04
0.04
0 .04
0.04
0.04
0.04 . --
0.04
0.04
0.04
0.04
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: C SURFACE: TAILINGS
AREA:COVER DEPLOYED: 6 12 12 RETRIEVED: 6
COUNTED BY: DLC FIELD 1ECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21 , M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: s1•F
13 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
143 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
C35
C36
C37
C38
C39
C40
C41
C42
C43
C44
C45
C46
C47
C48
C49
C50
C51
C52
C53
C54
C55
C56
C57
C58
C59
C60
C61
C62
C63
C64
C65
C66
C67
C68
C35
C36
C37
C38
C39
9 58 9 5 9 6 15 12 9
9 43 9 54 6 15 12 9
9 4 5 9 55 6 15 12 9
9 46 9 55 6 15_12 9
9 4 8 9 56 6 15 12 9
C40 9 49
C41 9 51
C42 9 53
C43 9 54
C44 9 56
C45 9 58
C46 10 0
C47 10 1
C48 10 2
C49 -10 3
C50 10 4
C51 10 5
C52 10 6
C53 10 7
C54 _1Q.. 8
C55 10 1
C56 10 2
C57 10 3
C58 10 4
C59 1 0 5
C60 10 6
C61 10 7
C62 1 0 8
C63 10 15
C64 10 16
C65 10 17
C66 10 18
C67 10 1 9
C68 10 20
9 57
9 57
9 58
9 58
9 59
9 59
10 4
10 4
10 5
10 5
10 6
10 6
10 7
10 8
10 8
10 4
10 4
10 5
10 5
10 6
10 6
10 7
10 8
10 1 8
10 1 9
10 20
10 20
10 2 1
10 22
6 15 12
6 15 12
6 15 12
6 15 12
6 15 12
6 15 12
6 15 12
6 15 12
6 15 12
6 1 s 12
6 15 12
6 15 12
6 15 12
6 15 12
~ 15 12
6 15 12
6 15 12
6 15 12
6 15 12
6 15 12
6 15 12
6 i s 12
6 1~-12
6 15 12
6 15 12
6 15 12
6 15 12
6 15 1 2
6 15 1 2
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
9
7
7
8
8
10
10
11
11
13
13
15
15
17
17
19
19
21
21
22
22
24
24
25
25
27
27
28
28
29
29
31
31
34
34
1
1
1
1
1
1
1
1
2
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
3
3
Page 2 of 3
5727 211.4
2414 222 .3
11150 211.3
19402 210.8
1646 211.7
1049
8426
2522
1516
10863
1005
1109
1539
3088
9084
5154
15429
32801
2242
10552
1708
1431
1180
1001
14817
34642
19874
11351
1812
5204
2784
3895
1247
1222
216.8
211.0
212.1
2 13 .0
2 11.3
210.5
212.7
2 14.3
213 .5
209.8
211.5
212.2
2 1 6.6
217.8
216 .5
214.8
2 11 .3
211.6
2 1 7.4
210.7
209.5
211.2
211.9
213.9
210.7
214.0
213.5
214.1
212 .9
11 .2
4 .5
22.0
~.2
3.0
1.8
16.6
4.7
1.2
21.3
1.7
0 .8
2.8
5 .9
18:0
10.0
30 .8
65.1
4 -:-2
20 .7
3.2
2.6
2.1
1.7
29.6
68 .8
39 :a
~2.4
3 .4
10.1
5.3
7.5
0 .5
0 .5
1.1
0 .4
2.2
3.8
0.3
0.2
1.7
0 .5
0.1
2.1
0.2
0.1
0 .3
0 .6
1.8
1.0
3.1
6 .5
0.4
2 .1
0.3
0 .3
0.2
0 .2
3 .0
6.9
4.0
2.2
0.3
1.0
0.5
0.7
0 .1
0 .1
0 .04
0 .04
0.04
0.04
0.04
0.04
0 .04
0.04
0.04
0.04
0.04
0 .04
0 .04
0 .04
0.04
0 .04
0.04
0.04
0.04
0.04
0.04
0 .04
0.04
0.04
0 .04
0 .04
0.04
0.04
0.04
0.04
0.04
0.01_
0.04
0 .04
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: C SURFACE: TAILINGS
AREA:COVER DEPLOYED: 6 12 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 51"F
13 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
143 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
C69
C70
C71
C72
C73
C74
C75
C76
C77
C78
C79
C80
C81
C82
C83
C84
C85
C86
C87
C88
C89
C90
C91
C92
C93
C94
C95
C96
C97
~98
C99
C100
C69 10 21. 10 22
C70 10 15 10 18
C71 10 16 10 19
C72 10 17 10 20
C73 10 18 10 20
C74 10 19 10 21
C75 10 20 10 22
C76 10 21 10 22
C77 10 22 10 23
C78 10 23 10 23
C79 10 24 10 24
C80 10 25 10 24
C81 -10 26 10 25
C82 ~ 1Q 27 10 25
C83 10 28 10 26
C84 10 22 10 23
C85 10 23 10 23
10 24 10 24
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 15 12 9
6 _1;.§..._}2 9
6 15 12 9
6 15 12 9
6 15 12 10
C86
C87
C88
C89
C90
C91
C92
C93
C94
C95
C96
C97
C98
C99
C100
u -10 25 10 24 6 15 12 10
10 26 10 25 6 15 12 10
10 27 10 25 6 15 ~12 n10
;to 28 10 26 §.._~12 10
10 22 10 27 6 15 12 10
10 23 10 27 6 15 12 10
10 24
10 25
10 26
10 22
10 23
10 24
10 25
10 26
10 28
10 28
10 29
10 27
10 27
10 28
10 28
10 29
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
6 15 12 10
38
36
41
42
44
44
45
48
51
52
55
54
57
57
58
58
0
2
1
4
4
5
5
7
7
8
8
9
9
10
11
4
1
1
2
1
1
1
3
1
2
2
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
2
1195
40407
4653
1732
3937
3919
1836
1098
180.91
1845
1817
1927
5015
~640
1230
1659
1078
211.6
213.8
209.2
219.6
211.3
213.2
215.1
210.9
213.6
213.0
215.6
218.4
209 .9
214.5
210 .9
214.2
220.1
1493 210.7
1311 209.7
5195 210.6
2559 212.1
2390 213.9
3618 213 .6
11377
3114
7111
13277
5725
68397
3383
1189
214 .1
209.8
220 .3
213.1
209.3
212 .8
214.0
209.8
AVERAGE RADON FLUX RATE FOR THE CELL 3 COVER REGION:
Page 3 of 3
0.3
_80 ;.].
9 .1
1.4
7:6
7.5
3.4
0.4
36.2
1.6
1.5
3.6
9 .8
5 .0
2.2
3 .0
1.~9
1.2
2.3
10.2
4.8
4.5
6.9
22.7
...2_,9
14.1
26.2 1u
136.2
6.5
0 .9
0.0
8.0
0.9
0 .1
0.8
0.8
0.3
0 .0
3.6
0.2
0.2
0.4
1.0
0 .5
0.2
0 .3
0 .2
0 .1
0.2
1.0
0.5
0.5
0 .7
2.3
0.6
1.4
2.6
1.1
13.6
0.7
0.1
14 .4 pCi/m2s
0.04
0.04 --~--0.04
0 .04
0.04
0.04
0 .04
0.04
0.04
0 .04
0.04
0 .04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0 .04
DESTROYED
0.04------~----~
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
0.04
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: D SURFACE: TAILINGS
AREA:COVER DEPLOYED: 6 13 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 56°F
14 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
146 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
DOl
D02
D03
D04
DOS
006
D07
DOS
D09
DlO
D11
D12
Dl3
014
DlS
Dl6
017
018
019
020
D21
D22
D23
D24
D25
026
027
D28
D29
D30
D31
D32
033
034
DOl
002
003
004
DOS
D06
D07
DOS
D09
010
Dll
D12
013
D14
D15
D16
017
D18
D19
020
D21
D22
D23
024
D25
026
D27
D28
D29
D30
031
D32
D33
D34
10 41 10 55
10 42 10 55
10 43 10 56
10 44 10 56
10 45 10 57
10 46 10 57
10 51 11 0
10 52 11 0
10 54 11 1
10 56 11 1
10 58 11 2
11 0 11 2
11 2 11 3
11 4 11 3
11 6 11 4
11 7 11 4
11 9 11 5
11 11 11 5
11 13 11 6
11 14 11 6
10 41 10 55
10 42 10 55
10 43 10 56
10 44 10 56
10 45 10 57
10 46 10 57
10 51 11 0
10 52 11 0
10 54 11 1
10 56 11 1
10 58 11 2
11 0 11 2
11 2 11 3
11 4 11 3
6 15 12 12
6 15 12 12
6 15 12 12
6 15 12 12
6 15 12 12
6 15.....!_? 12
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 1_2 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 _15 12 13
6 15 12 13
55
55
56
56
58
58
0
0
1
1
3
3
5
5
6
6
8
8
9
9
11
11
14
13
16
16
17
17
19
19
20
6 15 12 13 20
6 15 12 13 22
6 15 12 13 22
1 2356
1 11125
1 2180
1 25082
2 1667
2 -~1266
1 2086
1 10893
1 1475
1 27215
1 8369
1 38135
1 14230
1 6:?16
1 4842
1 7799
1 25468
1 13719
1 15686
1 10431
1 1547
1 12077
2 1982
1 27726
1 25280
1 -2..!§_43
1 4614
1 39075
1 19637
1 41445
1 12748
1 44363
1 5883
1 45840
Page 1 of 3
212.0
211.0
214.6
213.9
2~0 .1
214 .3
211.9
210.9
212.8
214.7
214.5
212.7
213 .1
210.3
209.7
211.4
210 .1
212.3
211.4
209.4
214.8
212.4
211.5
212.0
211.8
210.8
210.6
211.2
211 .4
207 .6
210.8
212.1
209.7
211.2
3 .8
18.5
3 .5
42.0
1.2
0.8
3.3
18 .2
2.3
45.8
14 .1
64.4
24:2
10.3
8 .1
13 .0
43 .6
23.1
26.8
17.6
2.4
20.1
1.4
46.6
42":9
41.4
7 .6
65.9
33.4
70.1
21.6
75.1
9 .9
77 .8
0.4
1.8
0 .3
4.2
0.1
0.1
0.3
1 .8
0 .2
4.6
1.4
6.4
2 .4
1.0
0.8
1.3
4.4
2.3
2.7
1.8
0.2
2.0
0.1
4.7
4.3
4.1
0.8
6 .6
3 .3
7.0
2.2
7 .5
1.0
7.8
0.03
0.03
0 .03
0.03
0.03
0 .03
0.03
0.03
0 .03
0.03
0.03
0.03
0.03
0.03
0 .03 -~--
0.03
0.03
0.03
0.03
0 .03
0.03
0.03
0 .03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0 .03
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: D SURFACE: TAILINGS
AREA:COVER DEPLOYED: 6 13 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M021D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 56•F
14 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
146 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
LOCATION I. D. HR MIN HR MIN i'iO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
D35
D36
037
038
039
040
041
042
043
044
D45
046
047
D48
049
050
051
052
053
D54
055
056
D57
058
D59
060
061
062
063
064
065
066
067
068
035
036
D37
038
D39
040
041
042
043
044
D45
046
047
048
D49
050
051
D52
D53
054
D55
056
057
058
D59
D60
061
062
D63
064
D65
06§.
067
068
11 6 11 4
11 7 11 4
11 9 11 5
11 11 11 5
11 13 11 6
11 14 11 6
11 16 11 7
11 16 11 7
11 17 11 8
11 18 11 8
11 19 11 9
11 20 11 9
11 21 11 10
11 22 11 10
1l-23 11 11
11 24 11 11
11 25 11 12
11 29 11 35
11 30 11 35
11 31 11 36
11 32 11 36
11 33 11 37
i1 34 11 37
11 35 11 38
11 36 11 38
11 37 11 39
11 16 11 7
11 16 11 7
11 17 11 8
11 18 11 8
h 19 11 9
1_.1 20 11 9
11 21 11 10
11 22 11 10
6 15 12 13 23
6 15 12 13 23
6 1s 12 13 25
6 15 12 13 25
6 15 12 13
6 15 12 13
6 15 ~ 12 13
6 15 12 13
6 15 12 1 3
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 _1,L 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 __15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 ~1.2_12 13
6 15 12 13
6 15 12 13
26
26
28
28
29
29
31
31
32
32
34
34
35
35
37
37
38
40
40
44
41
46
46
47
47
48
48
50
50
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
}
1
1
1
1
1
1
Page 2 of 3
1002
29559
26006
19559
24231
24972
37087
7363
7935
45000
53821
_1752
15236
1127
8754
8093
36450
13371
87806
t 2715
3627
6594
18030
1215
2110
3661
1722
1935
30225
13435
1 9632
12989
2067
210.8
208.1
212.2
209.4
209 .6
209 .7
209 .2
208.3
212.5
212.4
210.9
209.1
213.0
214.3
216.5
212 .6
210.9
210 .4
210 .6
209.8
212.6
212 .3
209.2
211.1
214.0
209.6
209.4
210.7
211.6
212.8
210.9
211.4
211.3
1.5
50.2
44.6
33 .2
41.6
42 .5
63.9
12.4
13 .5
76.8
93.0
_2 .§_
26.2
1.7
14 .9
13 .6
63 .0
22 .4
150.0
38.;_2
6.0
1l.l
30.3
0 .8
3 .3
6.1
2.7
3 .1
51.6
23 .1
3~.5
22 .3
3 .3
0.1
5.0
4.5
3.3
4.2
4.2
6.4
1.2
1.3
7.7
9.3
0.3
2.6
0 .2
1 .5
1.4
6.3
2.2
15.0
3.8
0 .6
1.1
3 .0
0.1
0.3
0.6
0 .3
0.3
5.2
2.3
3 .3
2.2
0.3
0.03
0 .03
0.03
0.03
0 .03
0.03
0.03
0 .03
0 .03
0.03
0 .03
0 . 03 -------0.03
0.03
0 .03
0.03
0.03
0 .03
0.03
0 .03
0.03
0.03
0 .03
0 .03
0.03
0 .03
0 .03
0.03
0.03
0.03
0 .03
VOID
0.03 -~--~
0.03
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: D SURFACE: TAILINGS
AREA: COVER DEPLOYED: 6 13 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/1 0/13
AIR TEMP MIN: 56°F
14 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
146 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS :
069
070
071
072
073
074
075
076
077
078
079
080
081
082
083
084
085
086
087
088
089
090
091
092
093
094
095
096
097
098
099
0100
069
070
071
072
073
074
075
076
077
078
079
080
081
082
D83
084
085
086
087
088
089
090
091
092
093
094
095
096
097
.£98
099
0100
11 23 11 11
11 24 11 11
11 25 11 12
11 29 11 35
11 30 11 35
11_31_11 36
11 32 11 36
11 33 11 37
11 36 11 40
11 37 11 40
11 38 11 41
11 39 11 41
11 4 0 11 42
11 41 11 42
11 4 2 11 43
11 43 11 4 3
11 44 11 44
11 4§_ 11 44
11 46 11 45
11 47 11 45
11 41 11 42
11 42 . 11 42
11 43 11 43
11 44 11 43
11 45 11 44
11 46 11 44
11 47 11 45
11 48 11 45
11 49 11 46
11 -~ ~1 46
11 44 11 4 7
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 15 12 13
6 1 5_ 1 2 13
6 15 12 13
6 15 12 13
6 1 5 12 13
6 15 12 14
6 15 12 14
6 15 12 14
6 15 12 14
6 15 12 14
6 1 5 12 14
6 15 12 14
6 15l 2 14
6 15 12 14
6 15 12 14
6 15 12 14
6 15 . 12 14
6 15 12 14
6 15 12 14
6 15 12 14
6 :15 12 14
6 15 12 14
6 15 12 14
6 15 12 1 4
6 15 12 14
6 15 12 14
6 15 12 14
51
51
52
52
53
53,
55
5 6
58
0
2
3
5
5
6
6
7
7
9
9
10
12
15
15
17
11
18
18
19
19
21
1
1
1
1
1
1
2
1
1
3
1
2
1
1
1
1
1
1
1
1
1
3
2
2
1
1
1
1
1
1
1
3270
6425
18341
20298
14415
12858
1741
1304
34188
1412
3328
1506
4970
15882
12567
1858
2527
4724
2116
3062
4039
1430
1493
1428
13482
3440
3617
8277
19236
6138
1 760
213.3
209.9
212.8
213.3
212.2
212.5
209 .9
209.4
212.1
210.9
211.7
212.7
213.9
2 10 .8
209.2
210.6
212 .1
p2 .2
209.9
211.7
210.7
210.1
209.6
211.3
210.7
211.8
213.0
211.1
210.1
210.7
212.4
11 45 11 47 6 15 12 14 22 2 1401 210.2
AVERAGE RADON FLUX RATE FOR THE CELL 2 COVER R.EGION:
Page 3 of 3
5.4 0.5 0.03
10.8 1.1 0.03
31.7 3 .2 0 .03
34 .2 3.4 0 .03
24 . 5 2 . 4 0 . 03
21.6 _ 2.2 q,.o3
1.2 0.1 0.03
2 .0 0.2 0.03
58.4 5.8 0.03
0 .6 0.1 0 .03
5 .5 0 .5 0 .03
1.0 0 .1 0 .03
8 .3 ~ 0.8 0 .03
26.8 2.7 0.03 ---21.4 2.1 0.03
2.9 0.3 0 .03
4 . 1 -o. 4 o :o3
7~ -0 . 8 -• .2.: •. .03
3 .4 0.3 0 .03
5 . 0 0 . 5 0 . 03
6.7 ~ 0.7 0.03
0.6 0.1 0...:.03
1.0 0 .1 0.03
1.0 0.1 0.03
23.0 -2.3 0.03
5 .6 -0 .6 0~3
6 .0 0 .6 0 .03
13 .9 1.4 0.03
33.0 -3 .3 0 .0 3
10 .2 -1. 0 -__L03
2.8 0 .3 0 .03
0 .9 0.1 0 .03
23 .1 pCi/m2 s
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: B SURFACE: TAILINGS
AREA: BEACH DEPLOYED: 6 11 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM J.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 64°F
12 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
145 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
B BLANK 1 B BLANK 1 8 34 8 32 6 1.4 12 18 38 10 1.846 207.7 0.09 0.03 0 .04 CONTROL
B BLANK 2 B BLANK 2_~ 34 8 32 6 14 12 18 49 10 1827 207.6 0.08 0.03 0.04 CONTROL
B BLANK 3 B BLANK 3 8 34 8 32 6 14 12 18 49 10 1820 207.1 0.08 0.03 0.04 CONTROL
B BLANK 4 B BLANK 4 8 34 8 32 6 14 12 19 0 10 1747 207.9 0.06 0.03 0.04 CONTROL
B BLANK 5 B BLANK 5 -8 34 8 32 6 14 12 19 0 10 1903 208.2 0.10 0.03 0.04 CONTROL
AVERAGE BLANK CANISTER ANALYSIS FOR THE CELL 3 BEACH REGION: 0.08 pCi/m2 s
Page 1 of 1
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 3 BATCH: C SURFACE: TAILINGS
AREA:COVER DEPLOYED: 6 12 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 51°F
13 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
143 cpm Wt. Out
TARE WEIGHT:
180.0
29.2
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS :
C BLANK 1 C BLANK 1 9 54 9 39 6 14-12 18 5 10 2165 209.1 0.13 0.03 0.03 CONTROL
C BLANK 2 C JLLANK 2 9_ 54 9 39 6 14 12 18 5 10 1895 207.9 0.08 0.02 0.03 CONTROL -C BLANK 3 C BLANK 3 9 54 9 39 6 14 12 18 16 10 2165 207.8 0.13 0.03 0.03 CONTROL
C BLANK 4 C BLANK 4 9 54 9 39 6 14 12 18 16 10 2149 207.6 0 .13 0.03 0.03 CONTROL
C BLANK 5 c BLANKS -9 54 9 39 6 14 12 18 27 10 2023 208.2 0.11 0.03 0.03 CONTROL
AVERAGE BLANK CANISTER ANALYSIS FOR THE CELL 3 COVER REGION: 0.12 pCi/m2 s
Page 1 of 1
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: D SURFACE: TAILINGS
AREA: COVER DEPLOYED: 6 13 12 RETRIEVED: 6
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,TE,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 56°F
14 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
146 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR ?-liN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
D BLANK 1 D BLANK 1 11 25 11 0 6 14 12 17 30 10 1742 208 .7 0 .04 0 .02 0 .03 CONTROL
D BLANK 2 D BLANK 2 11 25 11 0 6 14 12 17 30 10 1895 208 .8 0 .06 0 .02 0 .03 CONTROL ----D BLANK 3 D BLANK 3 11 25 11 0 6 14 12 17 42 10 1913 209 .4 0 .07 0 .02 0 .03 CONTROL
D BLANK 4 D BLANK 4 11 25 11 0 6 14 12 17 42 10 1899 209 .8 0 .07 0 .02 0 .03 CONTROL
D BLANK 5 D BLANK s· ~{ 25 0 6 -53 l 844 --0.02 0.03 CONTROL 11 14 12 17 10 209.6 0.06
AVERAGE BLANK CANISTER ANALYSIS FOR THE CELL 2 COVER REGION: 0.06 pCi/m2 s
Page 1 of 1
Appendix D
Sample Locations Map (Figure 2)
D
e VI w O v
IU
~ "'=> ~ 5 ~ .. !I 2~ ~ ldi ~ ... ~ ... ~ ow >: I lli!"' ~ 0 ... ! ~~ ~ wW 1n a:=> !! a. ...
(; • 0 § a: i 8 w z w
&o ao I. !O ~ ~0
ao
llo "
§0
go§ ~o ~0
§o~ j!io §o
§o~ I!Jo so
I §o ~ go
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Letter to B. Bird
March 29,2013
Page 12 of15
ATTACHMENT lB
Tellco Report on Annual Radon Flux Monitoring
September 2012
National Emission Standards for Hazardous Air Pollutants
2012 Radon Flux Measurement Program
White Mesa Mill
6425 South Highway 191
Blanding, Utah 84511
September 2012 Sampling Results
Prepared for: Energy Fuels Resources (USA) Inc.
6425 S. Highway 191
P.O. Box 809
Blanding, Utah 84511
Prepared by: Tellco Environmental
P.O. Box 3987
Grand Junction, Colorado 81 502
TABLE OF CONTENTS
Page
I. lNTRODUC'flON ........................................................................................................................... 1
2. SITE HISTORY AND DESCRIPTION .......................................................................................... 1
3. REGULATORY REQUfREMENTS FOR THE SITE .................................................................... 2
4. SAMPLfNG METHODOLOGY ..................................................................................................... 2
5. FIELD OPERATIONS .................................................................................................................... 3
5.1 Equip1nent Preparation ....................................................................................................... 3
5.2 Sample Locations, Identification, and Placement.. ........................................................... 3
5.3 Sample Retrieval ............................................................................................................... 4
5.4 Environmental Conditions ................................................................................................ 4
6. SAMPLE ANALYSTS ..................................................................................................................... 4
6.1 Apparatus ........................................................................................................................... 4
6.2 Sample Inspection and Documentation ............................................................................. 4
6.3 Background and Sample Coun ting .................................................................................... 5
7. QUALITY CONTROL (QC) AND DATA VALIDATION ........................................................... 5
7.1 Sensitivity .......................................................................................................................... 5
7.2 Precision ............................................................................................................................. 6
7.3 Accuracy ............................................................................................................................ 6
7.4 Completeness ..................................................................................................................... 6
8. CALCULATIONS ........................................................................................................................... 6
9. RESUL'r S ........................................................................................................................................ 7
9.1 Mean Radon Flux ............................................................................................................... 7
9.2 Site Results ......................................................................................................................... 8
References ............................................................................................................................................ 9
Figure! .............................................................................................................................................. tO
Appendix A. Charcoal Canister Analyses Support Documents
Appendix B. Recount Data Analyses
Appendix C . Radon Flux Sample Laboratory Data, Including Blanks
Appendix D. Sample Locations Map (Figure 2)
i
1. INTRODUCTION
During September 8-9, 2012, Tellco Environmental, LLC (Tellco) of Grand Junction, Colorado,
provided suppott to Energy Fuels Resources (USA) Inc. (Energy Fuels) to conduct additional radon
flux measurements regarding the required National Emission Standards for Hazardous Air Pollutants
(NESHAPs) Radon Flux Measurements. These measurements are required of Energy Fuels to show
compliance with Federal Regulations (further discussed in Section 3 below). The standard is not an
average per facility, but is an average per radon source. The standard allows mill owners or operators
the option of either making a single set of measurements or making measurements over a one year
period (e.g., weekly, monthly, or quarterly intervals).
Radon flux measurements were initially performed in June 2012 on Cell 2 and Cell 3 with the
intention of performing a single set of measurements to represent the year 2012 as allowed by the
regulations (Method 115). The results of the June 2012 sampling (presented in a separate report)
measured an arithmetic average radon flux rate of 23.1 picoCuries per square meter per second
(pCi/m2-s) for Cell 2 and 18.0 pCi/m2-s for Cell 3. Because the results for Cell 2 exceeded the
regulatory standard of 20 pCi/m2-s, Energy Fuels directed Tellco to perform additional radon flux
measurements of Cell 2 in September, October, and November 2012. This report addresses the results
of the September 2012 sampling while the June, October and November 2012 sampling results are
each presented in separate repot1s. No additional sampling of Cell 3 was performed because the
average radon flux rate measured by the June 20 12 sampling was below the regulatory standard.
Tellco was contracted to provide radon canisters, equipment, and canister placement personnel as well
as lab analysis of samples for calendar year 2012. Energy Fuels personnel provided support for
loading and unloading charcoal from the canisters. This report includes the procedures employed by
Energy Fuels and Tellco to obtain the results presented in Section 9.0 of this report.
2. SITE DESCRIPTION
The White Mesa Mill faci lity is located in San Juan County in southeastern Utah, six miles south of
Blanding, Utah. The mill began operations in 1980 for the purpose of extracting uranium and
vanadium from feed stocks. Processing effluents from the operation are deposited in four lined cells,
which vary in depth. Cell I, Cell4A, and Cell 48 did not require radon flux sampling, as explained in
Section 3 below.
Cell 2, which has a totaJ area of approximately 270,624 square meters (m\ has been filled and
covered with interim cover. Thi s cell was comprised of one region; a soil cover of varying thickness,
which required NESHAPs radon flux monitoring. The Cell 2 cover region was the same size in 2012
as it was in 20 II. There were no exposed tailings or standing liquid within Cell 2.
Cell 3, which has a total area of 288,858 m2, is nearly filled with tailings sand and is undergoing pre-
closure activities. This cell was comprised of two source regions that required NESHAPs radon
monitoring: at the time of the June 2012 radon sampling, approximately 219,054 m2 ofthe cell had a
soil cover of varying thickness and approximately 36,233 m2 of exposed tailings "beaches". The
remaining approximately 33,571 m2 was covered by standing liquid in lower elevation areas. The
1
standing liquid area was much smaller than in 20 II. Raffinate crystals and residue from the repair of
the original Cell 4A in 2006 have been placed in Cell 3.
The Cell 3 cover region area was larger during the 201 2 radon flu x sampling than it was for the 20 II
sampling prograrn. Due to worker health and safety concerns by both Energy Fuels and Tellco
personnel, portions of the unstable and wet beaches and covered areas were not sampled. The areas
tested for radon emanation are representative of the disposition of tailings for the 2012 reporting
period.
3. REGULATORY REQUIREMENTS FOR THE SITE
Radon emissions from the uranium mill tailings at this site are regulated by the State of Utah's
Division of Radiation Control and admihistcred by the Utah Division of Air Quality under generally
applicable standards set by the Environmental Protection Agency (EPA) for Operating Mills.
Applicable regulations are specified in 40 CFR Part 61 , Subpart W, National Emission Standards for
Radon Emissions from Operating Mill Tailings, with technical procedures in Appendix B. At present,
there are no Subpart T uranium mill tailings at this site. These regulations are a subset of the
NESHAPs. According to subsection 61.252 Standard, (a) radon-222 emissions to ambient ai r from an
existing uranium mill tailings pile shall not exceed an average of20 picoCuries per square meter per
second (pCi/m2-s) for each pile or region. Subsection 6l.253, Determining Compliance, states that:
"Compliance with the emission standard in this subpart shall be determined annually through the use
of Method 11 5 of Appendix B." The repaired Cell 4A, and newly constructed Cell 4B, were both
constructed after December 15, 1989 and each was constructed with less than 40 acres surface area.
Cell 4A and 48 comply with the requirements of 40 CFR 61 .252(b), therefore no radon flux
measurements are required on either Cell 4A or 48.
4. SAMPLING METHODOLOG Y
Radon emissions were measured using Large Area Activated Charcoal Canisters (canisters) in
conformance with 40 CFR, Patt 61, Appendix B, Method 115, Restrictions to Radon Flux
Measurements, (EPA, 2012). These are passive gas adsorption sampling devices used to detennine
the tlux rate of radon-222 gas from a surface. The canisters were constructed using a I 0-inch
diameter PVC end cap containing a bed of 180 grams of activated, granular charcoal. The prepared
charcoal was placed in the canisters on a support grid on top of a Y2 inch thick layer of foam and
secured with a retaining ring under I Yz inches of foam (see Figure l, page II).
One hundred sampling locations were distributed throughout Cell 2 (which consisted of one t•egion) as
depicted on the Sample Locations Map (see Figure 2, Appendix D). Each charged canister was placed
directly onto the surface (open face down) and exposed to the surface for 24 hours. Radon gas
adsorbed onto the charcoal and the stlbscquent radioactive decay of the entrained radon resulted in
radioactive lead-2 14 and bismuth-2 14. These radon progeny isotopes emit characteristic gamma
photons that can be detected through gamnla spectroscopy. The original total activity of the
adsorbed radon was calculated from these gamma ray measurements using calibration factors
derived from cross-calibration of standard sources containing known total activities of radium-226
with geometry identical to the counted samples and from the principles of radioactive decay.
After 24 hours, the exposed charcoal was transferred to a sealed plastic sampl e container (to prevent
radon loss and/or further exposure during transport), identified and labeled, and transported to the
2
Tcllco laboratory in Grand Junction, Colorado for analysis. Upon completion of on-site activities, the
field equipment was alpha and beta-gamma scanned for possible contamination resulting from
fieldwork activities. All field equipment was surveyed by Energy Fuels Radiation Safety personnel
and released for unrestricted use. Tell co personnel maintained custody of the samples from collection
through analysis.
5. FIELD OPERATIONS
5.1 Equipment Preparation
Al l charcoal was dried at II ooc before use in the fie ld. Unused charcoal and recycled charcoal were
treated the same. 180-gram aliquots of dried charcoal were weighed and placed in sample containers.
Proper balance operation was verified daily by checking a standard weight. The balance readout
agreed with the known standard weight to within ± 0. I percent.
After acceptable balance check, empty containers were individually placed on the balance and the
scale was re-zeroed with the container on the balance. Unexposed and dried charcoal was carefully
added to the container until the readout registered 180 grams. The lid was immediately placed on the
container and sealed with plastic tape. The balance was checked for readout drift between readings.
Sealed containers with unexposed charcoal were placed individually in the shielded counting wel l,
with the bottom of the container centered over the detector, and the background count rate was
documented. Three tive-minute background counts were conducted on ten percent of the containers,
selected at random to represent the "batch". If the background counts were too high to achieve an
acceptable lower limit of detection (LLD), the entire charcoal batch was labeled non-conforming and
recycled through the heating/drying process.
5.2 Sample Locations, ldentitlcation, and Placement
On September 8, 20 12, the sampling locations were spread out throughout the Cell 2 region. The same
designated sample point locations that were established for the June 2012 sampling of Cell 2 were
used for the September sampling. A sample identification number (10) was assigned to every sample
point, using a sequential alphanwneric system indicating the charcoal batch and physical location
within the region (e.g., HO 1 ... HI 00). This £0 was written on an adhesive label and affixed to the top
of the canister. The sample £0, date, and time of placement were recorded on the radon flux
measurements data sheets for the set of one hundred measurements.
Prior to placing a canister at each sample location, the retaining ring, screen, and foam pad of each
canister were removed to expose the charcoal support grid. A pre-measured charcoal charge was
selected from a batch, opened and distributed even ly act·oss the support grid. The canister was then
reassembled and placed face down on the surface at each sampling location. Care was exercised not
to push the device into the soil surface. The canister rim was "sealed" to the surface using a berm of
local borrow material.
Five canisters (blanks) were similarly processed and the canisters were kept inside an airtight plastic
bag during the 24-hour testing period.
3
5.3 Sample Retrieval
On September 9, 2012 at the end of the 24-hour testing period, all canisters were disassembled and
each charcoal sample was individually poured through a funnel into a container. Identification
numbers were transferred to the appropriate container, which was sealed and placed in a box for
transport. Retrieval date and time were recorded on the same data sheets as the sample placement
information. The blank samples were similarly processed.
All of the I 00 canisters placed throughout the Cell 2 sampling region were successfully retrieved and
all of the charcoal samples were successfully contajnerized during the unloading process.
5.4 Environmental Conditions
A rain gauge was in place at th e White Mesa Mill site to monitor rainfall and air temperatures during
sampling in order to ensure compliance with the regulatory measurement criteria.
In accordance with 40 CFR, Part 61, Appendix B, Method 1 15:
• Measurements were not initiated within 24 hours of rainfall.
• No rainfall occurred during any of the sampling periods.
6. SAMPLE ANALYSIS
6.1 Apparatus
Apparatus used for the analysis:
• Single-or multi-channel pulse height analysis system, Ludlum Model 2200 with a
Teledyne 3" x 3" sodium iodide, thallium-activated (Naf(TI)) detector.
• Lead shielded counting well approximately 40 em deep with 5-cm thick lead walls and a 7-
cm thick base and 5 em thick top.
• National Institute of Standards and Technology (NIST) traceable aqueous solution radium-
226 absorbed onto 180 grams of activated charcoal.
• Ohaus Model C50 I balance with 0.1-gram sensitivity.
6.2 Sample Inspection and Documentation
Once in the laboratory, the integrity of each charcoal container was verified by visual inspection of the
plastic container. Laboratory staff documented damaged or unsealed containers and verified that the
data sheet was complete.
All of the I 00 sample containers and 5 blank containers received and inspected at the Tellco analytical
laboratory were verified as valid.
4
6.3 Background and Sample Counting
The gamma ray counting system was checked daily, including background and radium-226 source
measurements prior to and aftct· each counting session. Based on calibration statistics, us ing two
sources with known radium-226 content, background and source control li mits were established for
each Ludlumr relcdyne counting system with shielded well (see Appendix A).
Gamma ray counting of exposed charcoal samples included the following steps:
• The length of count time was determined by the activity of the sample being analyzed,
according to a data quality objective of a minimum of I ,000 accrued counts for any given
sample.
• The sample container was centered on the Nal detector and the shielded well door was
closed.
• The sample was counted over a determined count length and then the mid-sample count
time, date, and gross countc;; were documented on the radon flux measurements data sheet
and used in the calculations.
• The above steps were repeated for each exposed charcoal sample.
• Approximately I 0 percent of the containers counted were selected for recounting. These
containers were recounted within a few days following the original count.
7. QUALITY CONTROL (QC) AND DATA VALIDATION
Charcoal flux measurement QC samples included the following intra-laboratory analytical frequency
objectives:
• Blanks, 5 percent, and
• Recounts, 10 percent
All sample data were subjected to validation protocols that included assessments of sensitivity,
precision, accuracy, and completeness. All method-required data quality objectives (EPA, 2012) were
attained.
7.1 Sensitivity
A total of five blanks were analyzed by measuring the radon progeny activity in samples subjected to
all aspects ofthe measurement process, excepting exposure to the source region. These blank sample
measurements comprised approximately 5 percent of the field measurements. The results of the blank
sample radon nux rates ranged from 0.02 to 0.05 pCi/m2-s, with an average of approximately 0.03
pCi/nl-s.
7.2 Precision
Ten recount measurements, distributed throughout the sample set, were performed by replicating
analyses of individual field samples (see Appendix 8). These recount measurements comprised
approximately 1 0 percent of the total number of samples analyzed. The precision of all recount
5
measurements, expressed as re lative percent difference (RPD), ranged from less than 1 percent to 6.5
percent with an overall average precision of approximately 2.0 percent.
7.3 Accuracy
Accuracy of field measurements was assessed daily by counting two laboratory control samples with
known Ra-226 content. Accuracy of these lab control sample measurements, expressed as percent
bias, ranged from approximately -0.1 percent to +2.2 percent. The arithmetic average bias of the lab
control sample measurements was approximately + 1.0 percent (see Appendix /\).
7.4 Completeness
One hundred samples from the Cell 2 Cover Region were veri fied, representing I 00 perce nt
completeness fo r the September 2012 radon flux sam piing.
8. CALCULATIONS
Radon flux rates were calculated for charcoal collection samples using calibration factors derived
fro m cross-calibration to sources with known total activity with identical geometry as the charcoal
contai ners. A yield efficiency factor was used to calculate the total activity of the sample charcoa l
con tainers. Individ ual field sample resul t values presented were not reduced by the res ults of the fie ld
blank analyses.
In practice, radon flux rates were calculated by a database computer program. The algorithms utilized
by the data base program were as follows:
Equation 8.1 :
pCi Rn-222/m2sec = [Ts* A *b*~.S\dl'.lt.7l5j
where: N =net sample count rate, cpm under 220-662 keY peak
Ts =sample duration, seconds
b =instrument calibration factor, cpm per pCi; values used:
0.1708, for M-0 1/D-21 and
0.1727, for M-02/D-20
d =decay Lime, elapsed hours between sample mid-time and counl mid-time
A =area of the canister, m2
Equation 8.2:
Gross Samp l e, cpm Background sarnple, cpm _ __;:.. _ __:_+----
SampleCount,t ,min Backgr ound Count,t ,min Err or,2o-= 2>< ....:.__;..._ _______ ___:. _______ ><Samp l e Concentration
Equation 8.3:
_ 2.71 +(4.65l(S~
LLD -[Ts* A *b*0.5(di<J 01s)]
Net ,cpm
6
where: 2.71 =constant
4.65 =confidence interval factor
sb =standard deviation ofthe background count rate
Ts =sample duration, seconds
b ""'instrument calibmtion factor, cpm per pCi; values used:
0.1708, for M-01/D-21 and
0.1727, for M-02/D-20
d =decay time, elapsed hours between sample mid-time and count mid-time
A ""'area of the canister, m2
9. RESULTS
9.1 Mean Radon Flu x
Referencing 40 CFR, Patt 61 , Subpart W, Appendix B, Method 115 -Monitoring for Radon-222
Emissions, Subsection 2.l.7 -Calculations, "the mean radon flux for each region of the pile and for
the total pile shall be calculated and reported as follows:
(a) The individual radon flux calculations shall be made as provided in Appendix A EPA
86(1 ). The mean radon flux for each region of the pile shall be calculated by summing all
individual flux measurements for the region and dividing by the total number of flux
measurements for the region.
(b) The mean radon flux for the total uranium mill tailings pile shall be calculated as follows:
A,
Where: J5 =Mean flux for the total pile (pC i/m2-s)
Ji =Mean flux measured in region i (pCi/m2-s)
Ai = Area of region i (m2)
1\, =Total area ofthe pile (m2)"
40 CI'R 61 , Subpart W, 1\ppendix B, Method 11 5, Subsection 2. I .8, Reporting states "The results of
individual flux measurements, the approximate locations on the pile, and the mean radon flux for each
region and the mean radon nux for the total stack [pile] shall be included in the emission test report. Any
condition or unusual event that occurred during lhe measurements that could significantly affect the results
should be reported."
7
9.2 Site Results
Site Specific Sample Results (reference Appendix C)
(a) The mean radon flux for each region within the site as follows:
Cell 2 -Cover Area 26.6 pCi/m2-s (based on 270,624 m2 area)
Note: Reference Append ix C of this report for the entire summary of individual measurement resu lts.
(b) Using the data presented above, the calculated mean radon flux for each cell (pile) is, as follows:
Cel12 = 26.6 pCi/m2-s
(26.6)(270,624) = 26.6
270,624
As shown above, the arithmetic mean radon !'lux for Cell 2 at Energy Fuels White Mesa milling
facility is slightly above the NRC and EPA standard of 20 pCi/m2-s. The unusually dry weather
wh ich was especially severe in 2012 likely lowered the water table at the site as well as reducing the
moisture content in surface soils. It is believed that this likely increased the radon flux rates over the
previous years' reported results. Appendix C is a summary of individual measurement results,
including blank sample analysis. Sample locations are depicted on Figure 2, which is included in
Appendix D. The map was produced by Tellco.
A
References
U. S. Environmental Protection Agency, Radon Flux Measurements on Gardinier and Royster
Pho.\phogypsum Piles Near Tampa and Mulbeny, Florida, EPA 520/5-85-029, NTIS #PB86-
161874, January 1986.
U. S. Environmental Protection Agency, Title 40, Code of Federal Regulations, July 2012.
U. S. Nuclear Regulatory Commission, Radiological Ejjluent and Environmental Monitoring at
Uranium Mills, Regulatory Guide 4.14, April 1980.
U. S. Nuclear Regu latory Commission, Title 10, Code of rederal Regulations, Part 40, Appendix A,
January 2012.
9
F igure 1
Large Area Activated Charcoal Canisters Diagram
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PYC En<f C~p
Appendix A
Charcoal Canister Analyses Support Documents
A
CHARCOAL CANISTER ANALYSIS SYSTEM
SITE LOCATION: \tV h A-~ Ne-st'\ 1'-1 ,'II, B lotVJd: Vl1) Y.T
cLIENT: 'De 111 >OV) M't >'\ es (usA) Corp.
Calibration Check Log
System ID: JiJ, -D '2.. / D -2 0 Calibration Date: _(e_f-0 9 / I L Due Date: ____f./_ 0 'J/ I f
Scaler S/N: SIS~) High Voltage:. ~?-.., '!> Window: 4.42 Thrshld: ___1,10 __
Detector SIN: 0 Y 1.5 ~2-Sotu·cc ID/SN: RPl "'2-2.. C<? /G-S-r}f:,ourcc Activity: ~ ·3 K.l2f;
B lm1k Canister Okgd. Range, cpm: 2 cr = l 2-f to I 5" :l.. 3 cr = I \ 7 to I §'C)
Gross Source Range, cpm: 2cr = 1.0'b1Lto \0 (o05 3cr= I Oll3
Technician: __ 1)_, __::z_;.....··_. -~-"'---1'-------
to 1 07 o:(_
All counts times are one minute
Date By Background Counts (1 min. each) Source Counts (I min. each ok?
#I #2 #3 Avg. fl.) 112 #3 Average YIN
lJ/cPJ/("1.. ~4>@< tt+O 1 '~2 1'35"' 1?;>'-l 058:2.. /O(pot J O~:S l 0'57?-y
0/00>/;'2-1,.:,7./...,;., 132> 138 I '-:)0) 137 I Ol.fOJS I 0'5"~ lo52-3 t05'3~ v
,;;; / ro/1""2--DL4>r{J' 1310 143 1;;(. e /3<,., i OS'€>7 I 0 '5'0):3 1 o5'64 /05135 )I
GJ)Io} n DLw ITl \44 I L/ I llf I lo4'1'2-IOt:;:c:;? I nc;·t.,P, 1 0530) ~"--f
YIN: Y = average background and source cpm falls within the control limits.
N =average background and source cpm does not fall within the control limits.
The acceptable ranges were determined from prior background and source check data.
CHARCOAL CANfSTER ANAL YSJS SYSTEM
SITE LOCATION: vJ h ~-\-c Me~ q tv\: I I , "B It/! v1 J,' 1'19 1 vt T
cuENT: 'D eVI.IS®_M I V\e~,___,(~vt:....::5:....'-A..:....·J,.,__--'=C=o~•,p=·----
Calibration Check Log
System ID: ~ -~ 0 ')... J 'D ·· 2 0 Calibration Date: v /-o 9 /.r2_ Due Date:~
Scaler SIN: S I 5 (;, 3 High Voltage: 'B "2. 5 Window: 4.42 Thrshld; 2.20
DctcctorS/N:O L\f5 '5::2.._ SourcelD/SN: R~22~/67 S,OS SourceActivity: s-q,3 Kf2C;
Blank Canister Bkgd. Range, cpm: 2 o = I '2.± to _I_$.=___ 3 <r:. I I I U> 1 ,$3 __
Gross Source Range, cpm: 2 o = 1 0 0 3 / to I 0 (a & / 3 <r = Of 5 t :l.. to ( 0 '8 ).. 0
Technician: :92L-C~-
All counts times are one minute
Date By Background Counts (I min. each) Source Counts (I min. each) ok?
#I #2 #3 Avg. #l #2 #3 i\veraAe YIN
i 9/00J}f').. ivr1....£v.>. ll./ 0 13?-1 .~5 /~6 10£..], 7 IO~Z..D I D.Sh3 10573 y
~lot?J) 1"2. "i372&u, L33 L3_£ I 30) l-:1,7 l 0 ~"2. JD5'25. i040l [Ot.f{(, y
10/10 I I ;2. IV2eo~ 1--~~~ J y 3 t-:2.~ t3(., _ _lOtp I t oseoo, IOb35 1 oc,o.5 '/
9/10/J"::J--I7;J'J.too. ~I :3/ 1Ylf 1.4J I LJ. I I 0 4<1'0 ios-.:;-) liDfo~:S 10.':)7 1 y
f
-
YIN: Y =average background and source cpm falls within the control limits.
N =average background and source cpm does not fall within the control limits.
The acceptablt: ranges were determined from prior background and source check data.
CHARCOAL CANISTER ANALYSIS SYSTEM
siTE LOCATION: W h~-t"( ts\e.!>"' M. ',II 1 R \~II) do"'?' , LiT
c;LIENT: \)-eV)<tSOI0 ('v\\V\eS ( lv\.$AJ (of'f
Calibration Check Log
System ID: fV\ -0 I / 'D -:L \
---i Calibration Date: (,/ ( 0 '1/1 2-Due Date: (p / 0" / I 3
Scaler S/N: 5 !57 2-:-, High Voltage: I I 2'5 _ Window: __ 4,Q___ Thrshld: _J.f.Q___
Detector SIN: Q_!:.L . .:.::IS=-3::::._.:3~----SoLtrceiD/SN: IJ<. ~ 221G7 S -Olf Source Activity: _5] '3 ~z
Blank Canister Bkgd. Range, cpm: 2 cr ""
Gross Source Range, cpm: 2 cr =
/ I 0) to l 5"'l? 3 cr .. ( f 0 to _l_jp..,_]"---
lOOcjS" to ro jf3 I 3cr= 01JC1 8 to_('OS7t8
Technician: ~-"'<p-::=:ir-------
All counts times are one minute
Date By Back~round Counts (I min. each) Source Counts (l min. cnch) ok?
f~l #2 #3 Avg. #l #2 #3 Average YIN
9}Q9_/_I--::i wa~~'" \3/ rJ/ 1:2-S 1~'-1 103~?--. t0"2....7'J I 0 l"JS' /028_{c:> 'I
0/0~/J?-DL~ 145' 't J-"j I t.f ~ 13° I OJ'-/0 · I o·~(..;-J t03"'8 ( 0'2..-0J s y
~Ito/ n-~ -r4~ 1.::2 cy_ J-:2-~ J3 '-,., {03:2-Y t0\'2Jf l 03'09 10'_2..7~ v
9/to) n-lh1,' 11-")... !3~ 1"2---<1 1'1-·:~ 10'17l I 0~"}1 to2..SS I 0 ~I 0) v
I
YIN: Y = average background and source cpm falls within the control limits.
N ,_,average backgrow1d and source cpm docs not fall within the control limits.
The acceptable ranges wen; detennincd from prior background and source check data.
CHARCOAL CAi'IISTER ANALYSIS SYSTEM
SITE LOCATION: w h ·, h fv\ 6(\ tv\ ~ II I B IV') V) d.,· V\.3 I VI T
cu ENT: 'De.V)\Son tv\\V\es (U.S{j~ Lo"'f·
Calibration Check Log
System 10: _M -0 l / D · 2 I
J
Scaler SIN: c,-I 5 7 ::2..
Detec.;tor SIN: 0 Lf f 53 3
Calibration Date: f.J? / 0~ / I 7_ Due Date: & / oq /.J3__
High Voltage: /I -.::2..5 Window: __ 4 . .11_ Thrshld: =2.2=0.__
Source 10/SN: Ro.:22 itq s-o 5 Source Activity: s-q r31< ~~
Blank Canister Dkgd. Range, cpm: 2 cr =~D)..:...._ __ to I 5'8 3 cr = _ __._( ~~ 0-=---to I (;, (
Gross Source Range, cpm: 2cr= l 0 0 so; to t 0 <;-2-3 3 cr =__..0 _0 _G:......=;.8_to [ 0 s-r t.f
Technician: __ p--'-"-_L __ ~---4-------
All counts times are one minute
Date By Background Counts (1 min. each) Source Counts (I min. each) ok?
#I #2 #3 Avg. #I #2 #3 Average YIN
q)oO)/r> ""· 131 1Lf7 1'2~ 13'f
IOJ ItO/ n-});_tt,q,. f-\ '"2-2. \ ~ 3 I 2._')_ j _:2-B
I
YIN: Y =average backgl'ound and source cpm falls within the control limits.
N = average background and source cpm does not fall within the control limits.
The acceptable ranges were determined from prior background and source check data.
Appendix B
Recount Data Analyses
B
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: H SURFACE: SOIL
AREA: COVER DEPLOYED: 9 8 12 RETRIEVED: 9
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 55°F
9 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD PRECISION
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s · % RPD
HlO
RECOUNT
H20
RECOUNT
H30
RECOUNT
H40
RECOUNT
H50
RECOUNT
H60
RECOUNT
H70
RECOUNT
HBO
RECOUNT
H90
RECOUNT
HlOO
RECOUNT
H10
HlO
H20
H20
H30
H30
H40
H40
H50
H50
H60
H60
H70
H70
HBO
HBO
H90
H90
H100
HlOO
8 40 9 0 9 9 12 20 32
8 40 9 0 9 10 12 7 49
8 55 9 9 9 9 12 20 39
8 55 9 9 9 10 12 7 49
9 12 9 19 9 9 12 20 46
9 12 9 19 9 10 12 7 51
8 57 9 10 9 9 12 20 52
8 57 9 10 9 10 12 7 51
9 42 9 37 9 9 12 20 59
9 42 9 37 9 10 12 7 52
9 27 9 28 9 9 12 21 6
9 27 9 28 9 10 12 7 52
9 22 9 23 9 9 12 21 13
9 22 9 23 9 10 12 7 54
9 3 9 13 9 9 12 21 25
9 3 9 13 9 10 12 7 54
8 37 8 57 9 9 12 21 34
8 37 8 57 9 10 12 7 58
8 33 8 53 9 9 12 21 43
8 33 8 53 9 10 12 7 57
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
1
1
25564 218.3
22425 218.3
7691 215.6
6859 215 .6
31945 218 .8
29006 218.8
41579 212 .1
38928 212 .1
11385 219 .0
9897 219 .0
1715 217 .1
1574 217 .1
10363 217 .4
9509 217 .4
1411 216 .5
1323 216 .5
1123 220 .6
1028 220 .6
1131 214.2
1139 214.2
38 .2
36.9
11.4
11.0
48.2
48.0
62.6
63 .7
17 .1
16 .3
2 .4
2.4
15.6
15 .6
0 .8
0 .8
0 .6
0 .6
1.5
1.6
3 .8
3 .7
1 .1
1 .1
4 .8
4.8
6 .3
6.4
1.7
1.6
0.2
0 .2
1.6
1.6
0.1
0.1
0.1
0 .1
0 .2
0.2
0 .03
0 .03
0.03
0 .03
0 .03
0.03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
3 .5%
3 .6%
0.4%
1 . 7%
4 .8%
0 .0%
0.0%
0 .0%
0 .0%
6 .5%
AVERAGE PERCENT PRECISION FOR THE CELL 2 COVER REGION: 2.0%
Page 1 of 1
Appendix C
Radon Flux Sample Laboratory Data (including Blanks)
c
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: H SURFACE: SOIL
AREA: COVER DEPLOYED: 9 8 12 RETRIEVED: 9
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 55"F
9 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
HOl
H02
H03
H04
H05
H06
H07
H08
H09
HlO
Hll
H12
H13
Hl4
H15
H16
H17
H18
H19
H20
H21
H22
H23
H24
H25
H26
H27
H28
H29
H30
H31
H32
H33
H34
HOl
H02
H03
H04
H05
H06
H07
H08
H09
HlO
Hll
H12
H13
H14
H15
H16
H17
H18
H19
H20
H21
H22
H23
H24
H25
H26
H27
H28
H29
H30
H31
H32
H33
H34
8 27 8 52
8 28 8 53
8 30 8 54
8 31 8 55
8 33 8 55
8 34 8 56
8 36 8 57
8 37 8 58
8 39 8 59
8 40 9 0
8 42 9 1
8 43 9 1
8 45 9 2
8 46 9 3
8 48 9 4
8 49 9 5
8 51 9 6
8 52 9 7
8 54 9 8
8 55 9 9
9 25 9 27
9 24 9 26
9 22 9 25
9 21 9 24
9 19 9 23
9 18 9 22
9 16 9 21
9 15 9 21
9 13 9 20
9 12 9 19
9 10 9 18
9 9 9 17
9 7 9 16
9 6 9 15
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 2 0
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
25
25
26
26
28
29
31
31
32
32
34
34
35
35
37
37
38
38
39
39
41
41
42
42
43
43
44
44
46
46
47
47
48
48
1
1
1
1
2
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
Page 1 of 3
4010
14468
27459
2392
1316
1640
2395
18140
2346
25564
9428
8180
17410
15174
9188
30712
28002
2352
19664
7691
2830
12598
1569
26833
15649
28361
3865
42212
25811
31945
14370
50079
9917
29644
214.3
214.4
220.6
219.0
217.2
215.9
214.7
216.4
222.6
218.3
219.9
216 .7
214.1
213.8
213 .7
216 .1
217.4
213 .0
214 .6
215.6
217 .6
215.7
216 .8
213 .9
216.5
218 .9
216 .5
217 .3
219 .5
218.8
216.3
218 .5
218.6
220 .4
5 .9
21.5
41.4
3 .4
0 .8
2.2
3 .4
27.0
3.3
38.2
14.1
12.1
26.3
22.6
13 .8
46 .1
42.5
3 .3
29 .8
11.4
4.1
18.9
2.2
40.5
23.8
42 .8
5.7
63 .7
39.3
48.2
21.8
75.6
14.9
44.6
0.6
2.1
4.1
0 .3
0.1
0.2
0 .3
2.7
0.3
3 .8
1.4
1.2
2.6
2.3
1.4
4.6
4.2
0.3
3.0
1.1
0.4
1.9
0 .2
4.0
2.4
4.3
0 .6
6.4
3.9
4.8
2.2
7 .6
1.5
4.5
0.03
0 .03
0 .03
0.03
0 .03
0.03
0.03
0.03
0.03
0.03
0.03
0 .03
0.03
0.03
0 .03
0 .03
0 .03
0.03
0.03
0 .03
0.03
0.03
0 .03
0 .03
0.03
0 .03
0 .03
0 .03
0 .03
0.03
0 .03
0 .03
0.03
0 .03
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: H SURFACE: SOIL
AREA: COVER DEPLOYED: 9 8 12 RETRIEVED: g.
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 55°F
9 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD·
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN} COUNTS WT IN pCi/m2 s pci/m2 s p<;:i/m2 s COMMENTS:
H35
H36
H37
H38
H39
H40
H4 1
H42
H43
H44
H45
H46
H47
H48
H49
H50
H51
H52
H53
H54
H55
H56
H57
H58
H59
H60
H61
H62
H63
H64
H65
H66
H67
H68
H35
H36
H37
H38
H39
H40
H4 1
H42
H43
H44
H45
H46
H47
H48
H49
H50
H51
H52
H53
H54
H55
H56
H57
H58
H59
H60
H61
H62
H63
H64
H65
H66
H67
H68
9 4
9 3
9 1
9 0
8 58
8 57
9 55
9 54
9 52
9 51
9 49
9 48
9 46
9 45
9 43
9 42
9 40
9 39
9 37
9 36
9 34
9 33
9 31
9 30
9 28
9 27
9 9
9 10
9 12
9 13
9 15
9 16
9 18
9 19
9 14
9 14
9 13
9 12
9 11
9 10
9 43
9 43
9 42
9 41
9 4 1
9 40
9 39
9 38
9 37
9 37
9 36
9 35
9 34
9 33
9 32
9 32
9 31
9 30
9 29
9 28
9 17
9 18
9 19
9 20
9 21
9 22
9 23
9 24
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 20
9 9 12 2 0
9 9 12 20
9 9 12 2 0
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
50
50
51
51
52
52
54
54
55
55
56
56
58
58
59
59
0
0
2
2
3
3
4
4
6
6
8
8
9
9
11
11
12
12
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
1
1
1
1
1
1
1
1
1
Page 2 of 3
3094
41126
22637
32569
39760
41579
44131
11231
10895
58806
68353
3797
16055
1761
17985
11385
40883
17192
112824
39893
4527
155050
7658
19298
1323
1715
5859
4107
2448
60642
17889
21495
26416
3454
219 .0
213 .9
217.7
213 .0
214.4
212 .1
216.0
217.9
217 .1
214.8
213.1
215.9
218 .6
217 .3
212 .2
219 .0
216 .7
221 .7
216 .4
222 .9
222.0
216 .5
218 .6
214 .1
220 .1
217 .1
219 .6
216 .2
215 .4
216 .7
213 .6
216.4
215 .3
215 .7
4 .5
62 .0
34.4
49 .0
60.5
62 .6
68 .0
16 .9
16 .6
89 .6
105 .3
5.6
24 .5
2 .5
27 .5
17.1
62.8
26 .0
173 .6
60 .6
6.7
235 .9
11.6
29 .2
0 .8
2.4
8 .8
6 .0
3.5
91 .9
27 .3
32.4
40 .4
5.0
0 .5
6.2
3.4
4 .9
6 .1
6 .3
6.8
1.7
1.7
9.0
10.5
0.6
2 .5
0 .2
2.8
1.7
6 .3
2.6
17.4
6 .1
0 .7
23 .6
1.2
2.9
0 .1
0 .2
0 .9
0 .6
0 .4
9 .2
2 .7
3.2
4 .0
0 .5
0 .03
0 .03
0.03
0 .03
0 .03
0.03
0 .03
0 .03
0.03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0.03
0 .03
0.03
0.03
0 .03
0.03
0 .03
0 .03
0 .03
0 .03
0.03
0.03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: H SURFACE: SOIL
AREA: COVER DEPLOYED: 9 8 12 RETRIEVED: 9
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 55°F
9 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT ·GROSS GROSS RADO;-:r ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN {MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
H69
H70
H71
H72
H73
H74
H75
H76
H77
H78
H79
H80
H81
H82
H83
H84
H85
H86
H87
H88
H89
H90
H91
H92
H93
H94
H95
H96
H97
H98
H99
H100
H69
H70
H71
H72
H73
H74
H75
H7 6
H77
H78
H79
H80
H81
H82
H83
H84
H85
H86
H87
H88
H89
H90
H91
H92
H93
H94
H95
H96
H97
H98
H99
HlOO
9
9
9
9
9
9
9
9
9
9
9
9
9
9
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
8
21
22
24
25
27
28
30
31
7
6
4
3
1
0
58
57
55
54
52
51
36
37
39
40
42
43
45
46
48
30
9 25
9 26
9 27
9 28
9 29
9 30
9 31
9 32
9 16
9 15
9 14
9 1 3
9 12
9 11
9 10
9 9
9 8
9 7
9 6
9 5
8 56
8 57
8 58
8 5 9
9 0
9 1
9 2
9 3
9 4
8 55
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
9 9 12 21
13
13
15
15
17
17
19
19
21
22
24
25
27
27
29
29
30
30
32
32
33
34
3 7
36
39
39
40
40
42
42
1
1
1
1
1
1
1
1
1
2
1
2
1
1
1
1
1
1
1
1
1
2
2
1
1
1
1
1
1
1
4504
10363
16101
25537
6054
13528
1254
1496
45654
1376
4706
1411
4851
18234
16722
2016
4548
3021
2785
4295
4951
1123
1225
1582
5204
4205
3700
3809
23703
10320
218 .4
217 .4
223 .7
221.3
220 .7
215 .4
220 .1
215 .7
213.0
218.1
214.6
2 16.5
217.8
215.0
217 .4
2 18 .3
215.6
218 .4
217 .6
216 .1
214.7
220 .6
217 .7
230 .8
216.8
218.3
216.6
215.9
215 .5
217 .9
31 8 54 9 9 12 21 43 1 1339 215 .9
33 8 53 9 9 12 21 43 1 1131 214.2
AVERAGE RADON FLUX RATE FOR THE CELL 2 COVER REGION:
Page 3 of 3
6.7 0 .7
15 .5 1.6
24.6 2.5
38 .6 3.9
9.1 0.9
20.4 2 .0
1.7 0 .2
2 .1 0.2
69 .9 7.0
0 . 8 0 .1
7 . 0 0. 7
0 .8 0 .1
7 .2 0.7
2 7 .5 2.7
25 .5 2.5
2 . 8 0.3
6 .8 0 .7
4 . 4 0. 4
4 .1 0.4
6 . 3 0. 6
7.4 0. 7
0 .6 0.1
0 .7 0 .1
2 .2 0 . 2
7 .8 0. 8
6.2 0. 6
5.5 0.5
5.6 0. 6
36.2 3 .6
15.4 1.5
1.8 0 .2
1.5 0.1
26.6 pCi/m2 s
0.03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0.03
0.03
0 .03
0 .03
0.03
0 .03
0 .03
0 .03
0 .03
0 .03
0 .03
0.03
0.03
0 .03
0 .03
0 .03
0.03
0 .03
0 .03
0.03
0.03
0 .03
0 .03
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: H SURFACE: SOIL
AREA:COVER DEPLOYED: 9 8 12 RETRIEVED: 9
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 55°F
9 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE RETRIV ANALYSIS MID -TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
H BLANK 1 H BLANK 1 8 25 8 45 9 9 12 21 49 10 1750 209 .5 0 .04 0 .02 0 .03 CONTROL
H BLANK 2 H BLANK 2 8 25 8 45 9 9 12 21 49 10 1626 210 .5 0.02 0 .02 0 .03 CONTROL
H BLANK 3 H BLANK 3 8 25 8 45 9 9 12 22 0 10 1779 209 .4 0 .05 0 .02 0 .03 CONTROL
H BLANK 4 H BLANK 4 8 25 8 45 9 9 12 22 0 10 1671 207 .4 0 .03 0 .02 0.03 CONTROL
H BLANK 5 H BLANK 5 8 25 8 45 9 9 12 22 12 10 1656 208 .2 0 .03 0 .02 0.03 CONTROL
AVERAGE BLANK CANISTER ANALYSIS FOR THE CELL 2 COVER REGION : 0 .03 pCi/m2 s
Page 1 of 1
Appendix D
Sample Locations Map (Figure 2)
D
* \!) V'> ~s §~~~ z UJ
~ ~11 !c>
-' u ~ );!
~ -"-0~~
-' ::l: "'=> l! j --~ ~9.sl!::<
::E co .. ~ .. V'>. ~ 1! .. ~ --~ )!.'"« ~
Ow
~ ~!lOll
<( M wo:;
~ 0 ~~ "@8~ 0 "'"'
~~§~~
UJ ~ ....
~
:::;_; M "'"' ~~ "' o:::>
U~i~
UJ w a. ....
1!
1-"" >-J: a; \!) 0
ai~ig
3: a: i §; w
~"~0
z V'> w
~0 ro !0
lo 'fO ~0 ~0
~o i !O ~ ~0
i o i o ~0 !0
I J ~0 ~0 !o to tO ! I .
§ y :>o :zo ~0 lO f o I "
io ::;o to ~ i o . '{
io ~0 J ~0 !0 ! ~o~ ~o I ~ io ~
a "'! ~0 20"' ~0 f2o
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Letter to B. Bird
March 29, 2013
Page 13 of 15
A TI ACHMENT 1 C
Tellco Report on Annual Radon Flux Monitoring
October 2012
National Emission Standards for Hazardous Air Pollutants
2012 Radon Flux Measurement Program
White Mesa Mill
6425 South Highway 191
Blanding, Utah 84511
October 2012 Sampling Results
Prepared for: Energy Fuels Resources (USA) Inc.
6425 S. Highway 191
P.O. Box 809
Blanding, Utah 84511
Prepared by: Tellco Environmental
P.O. Box 3987
Grand Junction, Colorado 81502
TABLE OF CONTENTS
Page
1. INTRODUCTION ........................................................................................................................... 1
2. SITE HISTORY AND DESCRJPTION .......................................................................................... I
3. REGULATORY REQUIREMENTS FOR THE SITE .................................................................... 2
4. SAMPLING METHODOLOGY ..................................................................................................... 2
5. FIELD OPERA TTONS .................................................................................................................... 3
5.1 Equipment Preparation ....................................................................................................... 3
5.2 Sample Locations, Identification, and Placement.. ........................................................... 3
5.3 Sample Retrieval ............................................................................................................... 4
5.4 Environmental Conditions ................................................................................................ 4
6. SAMPLE ANALYSIS ..................................................................................................................... 4
6.1 Apparatus ........................................................................................................................... 4
6.2 Sample Inspection and Documentation ............................................................................. 4
6.3 Background and Sample Counting .................................................................................... 5
7. QUALITY CONTROL (QC) AND DATA VALIDATION ........................................................... 5
7.1 Sensitivity .......................................................................................................................... 5
7.2 Precision ............................................................................................................................. 6
7.3 Accuracy ............................................................................................................................ 6
7.4 Completeness ..................................................................................................................... 6
8. CALCULATIONS ........................................................................................................................... 6
9. RESULTS ........................................................................................................................................ 7
9.1 Mean Radon Flux ............................................................................................................... 7
9.2 Site Results ......................................................................................................................... 8
References ............................................................................................................................................ 9
Figure 1 .............................................................................................................................................. 10
Appendix A. Charcoal Canister Analyses Support Documents
Appendix B. Recount Data Analyses
Appendix C. Radon Flux Sample Laboratory Data, Including Blanks
Appendix D. Sample Locations Map (Figure 2)
i
1. INTRODUCTION
During October 20-2l, 2012, Tellco Environmental, LLC (Tellco) of Grand Junction, Colorado,
provided support to Energy Fuels Resources (USA) Inc. (Energy Fuels) to conduct additional radon
flux measurements regarding the required National Emission Standards for Hazardous Air Pollutants
(NESHAPs) Radon Flux Measurements. These measurements are required of Energy Fuels to show
compliance with Federal Regulations (further discussed in Section 3 below). The standard is not an
average per facility, but is an average per radon source. The standard allows mill owners or operators
the option of either making a single set of measurements or making measurements over a one year
period (e.g., weekly, monthly, or quarterly intervals).
Radon flux measurements were initially performed in June 2012 on Cell 2 and Cell 3 with the
intention of performing a single set of measurements to represent the year 2012 as allowed by the
regulations (Method 115). The resuJts of the June 2012 sampling (presented in a separate report)
measured an arithmetic average radon flux rate of 23.1 picoCuries per square meter per second
(pCi/m2-s) for Cell 2 and 18.0 pCi/m2-s for Cell 3. Because the results for Cell 2 exceeded the
regulatory standard of 20 pCi/m2-s, Energy Fuels directed Tellco to perform additional radon flux
measurements of Cell 2 in September, October, and November 2012. This report addresses the results
of the October 2012 sampling while tbe June, September, and November 2012 sampling results are
each presented in separate reports. No additional sampling of Cell 3 was performed because the
average radon flux rate measured by the June 2012 sampling was below the regulatory standard.
Tellco was contracted to provide radon canisters, equipment, and canister placement personnel as well
as lab analysis of samples for calendar year 20 12. Energy Fuels personnel provided support for
loading and unloading charcoal from the canisters. This report includes the procedures employed by
Energy Fuels and Tellco to obtain the results presented in Section 9.0 of this report.
2. SITE DESCRIPTION
The White Mesa Mill facility is located in San Juan County i11 southeastern Utah, six miles south of
Blanding, Utah. The mill began operations in 1980 for the purpose of extracting uranium and
vanadium from feed stocks. Processing effluents from the operation are deposited in four lined cells,
which vary in depth. Cell 1, Cell 4A, and Cell 4B did not require radon flux sampling, as explained in
Section 3 below.
Cell 2, which has a total area of approximately 270,624 square meters (m2), has been filled and
covered with interim cover. This cell was comprised of one region; a soil cover of varying thickness,
which required NESHAPs radon flux monitoring. The Cell 2 cover region was the same size in 2012
as it was in 20 ll. There were no exposed tailings or standing liquid within Cel12.
Cell 3, which has a total area of288,858 m2, is nearly filled with tailings sand and is undergoing pre-
closure activities. This cell was comprised of two source regions that required NESHAPs radon
monitoring: at the time of the June 2012 radon sampling, approximately 219,054 m2 of the cell had a
soil cover of varying thickness and approximately 36,233 m2 of exposed tailings "beaches". The
remaining approximately 33,571 m2 was covered by standing liquid in lower elevation areas. The
1
standing liquid area was much smaller than in 201l. Raffinate crystals and residue from the repair of
the original Cell 4A in 2006 have been placed in Cell 3.
The Cell 3 cover region area was larger during the 2012 radon flux sampling than it was for the 2011
sampling program. Due to worker health and safety concerns by both Energy Fuels and Tellco
personnel, pmtions of the unstable and wet beaches and covered areas were not sampled. The areas
tested for radon emanation are representative of the disposition of tailings for the 2012 reporting
period.
3. REGULATORY REQUIREMENTS FOR THE SITE
Radon emissions from the uranium mill tailings at this site are regulated by the State of Utah's
Division of Radiation Control and administered by the Utah Division of Air Quality under generally
applicable standards set by the Environmental Protection Agency (EPA) for Operating Mills.
Applicable regulations are specified in 40 CPR Part 61, Subpart W, National Emission Standards for
Radon Emissions from Operating Mill Tailings, with technical procedures in Appendix B. At present,
there are no Subpart T uranium mill tailings at this site. These regulations are a subset of the
NESHAPs. According to subsection 61.252 Standard, (a) radon-222 emissions to ambient air from an
existing uranium mill tailings pile shall not exceed an average of20 picoCuries per square meter per
second (pCi/m2-s) for each pile or region. Subsection 61.253, Determining Compliance, states that:
"Compliance with the emission standard in this subpart shall be determined annually through the use
of Method 11 5 of Appendix B." The repaired Cell 4A, and newly constructed Cell 4B, were both
constructed after December 15, I 989 and each was constructed with less than 40 acres surface area.
Cell 4A and 4B comply with the requirements of 40 CFR 61.252(b), therefore no radon flux
measurements are required on either Cell 4A or 4B.
4. SAMPLING METHODOLOGY
Radon emissions were measured using Large Area Activated Charcoal Canisters (canisters) in
conformance wrth 40 CFR, Part 61, Appendix B, Method 115, Restrictions to Radon Flux
Measurements, (EPA, 20 I 2). These are passive gas adsorption sampling devices used to determine
the flux rate of radon-222 gas from a surface. The canisters were constructed using a lO-inch
diameter PVC end cap containing a bed of 180 grams of activated, granular charcoaL The prepared
charcoal was placed in the canisters on a support grid on top of a Y2 inch thick layer of foam and
secured with a retaining ring under 1 Y2 inches of foam (see Figure 1, page 11 ).
One hundred sampling locations were distributed throughout Cell2 (which consisted of one region) as
depicted on the Sample Locations Map (see Figure 2, Appendix D). Each charged canister was placed
directly onto the surface (open face down) and exposed to the surface for 24 hours. Radon gas
adsorbed onto the charcoal and the subsequent radioactive decay of the entrained radon resulted in
radioactive lead-214 and bismuth-214. These radon progeny isotopes emit characteristic gamma
photons that can be detected through gamma spectroscopy. The original total activity of the
adsorbed radon was calculated from these gamma ray measurements using calibration factors
derived from cross-calibration of standard sources containing known total activities of radium-226
with geometry identical to the counted samples and rrom the principles of radioactive decay.
After 24 hours, the exposed charcoal was transferred to a sealed plastic sample container (to prevent
radon loss and/or further exposure during transport), identified and labeled, and transported to the
2
Tellco laboratory in Grand Junction, Colorado for analysis, Upon completion of on-site activities, the
field equipment was alpha and beta-gamma scanned for possible contamination resulting from
fieldwork activities. All field equipment was surveyed by Energy Fuels Radiation Safety personnel
and released for unrestricted use. Te.llco personnel maintained custody of the samples from collection
through analysis.
5. FIELD OPERATfONS
5.1 Equipment Preparation
All charcoal was dried at 11 0°C before use in the field. Unused charcoal and recycled charcoal were
treated the same. 180-gram aliquots of dried charcoal were weighed and placed in sample containers.
Proper balance operation was verified daily by checking a standard weight. The balance readout
agreed with the known standard weight to within ± 0.1 percent.
After acceptable balance check, empty containers were individually placed on the balance and the
scale was re-zeroed with the container on the balance. Unexposed and dried charcoal was carefully
added to the container until the readout registered 180 grams. The lid was immediately placed on the
container and sealed with plastic tape. The balance was checked for readout drift between readings.
Sealed containers with unexposed charcoal were placed individually in the shielded counting well,
with the bottom of the container centered over the detector, and the background count rate was
documented. Three five-minute background counts were conducted on ten percent of the containers,
selected at random to represent the "batch". lf the background cow1ts were too high to achieve an
acceptable lower limit of detection (LLD), the entire charcoal batch was labeled non-conforming and
recycled through the heating/drying process.
5.2 Sample Locations, Identification, and Placement
On October 20, 2012, the sampling locations were spread out throughout the Cell 2 region. The same
original designated sample point Jocations that were established for the June 2012 sampling of Cell 2
were used for the October sampling. A sample identification nwnber (ID) was assigned to every
sample point; using a sequential alphanumeric system indicating the charcoal batch and physical
location within the region (e.g., GOI ... GlOO). This ID was written on an adhesive label and affixed to
the top of the canister. The sample ID, date, and time of placement were recorded on the radon flux
measurements data sheets for the set of one hundred measurements.
Prior to placing a canister at each sample location, the retaining ring, screen, and foam pad of each
canister were removed to expose the charcoal support grid. A pre-measured charcoal charge was
selected from a batch, opened and distributed evenly across the support grid. The canister was then
reassembled and placed face down on the surface at each sampling location. Care was exercised not
to push the device into the soil surface. The canister rim was ''sealed" to the surface using a berm of
local borrow material.
Five canisters (blanks) were similarly processed and the canisters were kept inside an airtight plastic
bag during the 24-hour testing period.
3
5.3 Sample Retrieval
On October 21, 2012 at the end of the 24-hour testing period, all canisters were retrieved,
disassembled and each charcoal sample was individually poured through a funnel into a contaJner.
Identification numbers were transferred to the appropriate contaJner, which was sealed and placed in a
box for transport. Retrieval date and time were recorded on the same data sheets as the sample
placement information. The blank samples were similarly processed.
All of the 100 canisters placed throughout the Cell 2 sampling region were successfully retrieved and
all of the charcoal samples were successfully containerized during the unloading process.
5.4 Environmental Conditions
A rain gauge was in place at the White Mesa Mill site to monitor rainfall and air temperatures during
sampling in order to ensure compliance with the regulatory measurement criteria
In accordance with 40 CFR, Part 61, Appendix B, Method 115:
• Measurements were not in itiated within 24 hours of rainfall.
• No rainfall occurred during any of the sampling periods.
6. SAMPLE ANALYSIS
6.1 Apparatus
Apparatus used for the analysis:
• Single-or multi-channel pulse height analysis system, Ludlum Model 2200 with a
Teledyne 3" x 3" sodium iodide, thallium-activated (Nai(TI)) detector.
• Lead shielded counting well approximately 40 em deep with 5-cm thick lead walls and a 7-
em thick base and 5 em thick top.
• National Institute of Standards and Technology (NlST) traceable aqueous solution radium-
226 absorbed onto 180 grams of activated charcoal.
• Ohaus Model C501 balance wjth 0.1 -gram sensitivity.
6.2 Sample Inspection and Documentation
Once in the laboratory, the integrity of each charcoal container was verified by visual inspection of the
plastic container. Laboratory staff documented damaged or unsealed containers and verified that the
data sheet was complete.
All of the 100 sample containers and 5 blank containers re<:eived and inspected at the Tell co analytical
laboratory were verified as valid.
4
6.3 Background and Sample Counting
The gamma ray counting system was checked daily, including background and radium-226 source
measurements prior to and after each counting session. Based on calibration statistics, using two
sources with known radium-226 content, background and source control limits were established for
each Ludlum!feledyne counting system with shielded well (see Appendix A).
Gamma ray counting of exposed charcoal samples included the following steps:
• The length of count time was determined by the activity of the sample being analyzed,
according to a data quality objective of a minimum of I ,000 accrued counts for any given
sample.
• The sample container was centered on the Nal detector and the shielded well door was
closed.
• The sample was counted over a determined count length and then the mid-sample count
time, date, and gross counts were documented on the radon flux measurements data sheet
and used in the calculations.
• The above steps were repeated for each exposed charcoal sample.
• Approximately I 0 percent of the containers counted were selected for recounting. These
containers were recounted within a few days following the original count.
7. QUALITY CONTROL(QC)AND DATA VALIDATION
Charcoal flux measurement QC samples included the following intra-laboratory analytical frequency
objectives:
• Blanks, 5 percent, and
• Recounts, I 0 percent
All sample data were subjected to validation protocols that included assessments of sensitivity,
precision, accuracy, and completeness. All method-required data quality o~jectives (EPA, 2012) were
attained.
7.1 Sensitivity
A total of five blanks were analyzed by measuring the radon progeny activity in samples subjected to
all aspects of the measurement process, excepting exposure to the source region. These blank sample
measurements comprised approximately 5 percent of the field measurements. The results of the blank
sample radon flux rates ranged from 0.04 to 0.06 pCilm2-s, with an average of approximately 0.05
pCi/m2-s.
7.2 Precision
Ten recount measurements, distributed throughout the sample set, were performed by replicating
analyses of individual field samples (see Appendix B). These recount measurements comprised
approximately 10 percent of the total number of samples analyzed. The precision of all recount
5
measurements, expressed as relative percent difference (RPD), ranged from less than 1 percent to 5.7
percent with an overall average precision of approximately 2.4 percent.
7.3 Accuracy
Accuracy of field measurements was assessed daily by counting two laboratory control samples with
known Ra-226 content. Accuracy of these lab control sample measurements, expressed as percent
bias, ranged from approximately -1.4 percent to + 1.9 percent. The arithmetic average bias of the lab
control sample measurements was approximately +0.0 percent (see Appendix A).
7.4 Completeness
One hundred samples from the Cell 2 Cover Region were verified, representing 100 percent
completeness for the October 2012 radon flux sampling.
8. CALCULATIONS
Radon flux rates were calculated for charcoal collection samples using calibration factors derived
from cross-calibration to sources with known total activity with identical geometry as the charcoal
containers. A yield efficiency factor was used to calculate the total activity of the sample charcoal
containers. Individual field sample result values presented were not reduced by the results of the field
blank analyses.
In practice, radon fl ux rates were calculated by a database computer program. The algorithms utilized
by the data base program were as follows:
Equation 8.1:
pCi Rn-222/rn2sec = [Ts* A *b*~.s(d/91.75)]
where: N =net sample count rate, cpm under 220-662 keY peak
Ts = sample duration, seconds
b = instrument calibration factor, cpm per pCi; values used:
0.1708, for M-0 1/0-21 and
0.1727, for M-02/0-20
d =decay time, elapsed hours between sample mid-time and count mid-time
A =area of the canister, m2
Equation 8.2:
Gross Sample , cpm Background Sampl e , cpm /------~~~~+----~----~~~~
SampleCount,t ,min Background Count,t ,mi n Error, 2a = 2 x --=-------------------------------------x Sample Concen t rat ion
Net, cpm
6
Equation 8.3:
_ 2.71 + (4.65)(S~.)
LLD-(Ts* A *b*O.s<c:Wf'ls))
where: 2.71 =constant
4.65 =confidence interval factor
sb =standard deviation of the background count rate
Ts =sample duration, seconds
b =instrument calibration factor, cpm per pCi; Values used:
0.1708, for M-01/D-21 and
0.1727, for M-02/D-20
d =decay time, elapsed hours between sample mid-time and count mid-time
A ~area of the canister, m2
9. RESULTS
9.1 Mean Radon Flux
Referencing 40 CFR, Part 61 , Subpart W, Appendix B, Method 115 -Monitoring for Radon~222
Emissions, Subsection 2.1.7 -Calculations, "the m,ean radon flux for each region of the pile and for
the total pile shall be calculated and reported as follows:
(a) The individual radon flux calculations shall be made as provided in Appendix A EPA
86(1). The mean radon flux for each region of the pile shall be calculated by summing all
individual flux measUiements for the region and dividing by the total number of flux
measurements for the region.
(b) The mean radon flux for the total uranium mill tailings pile shall be calcuJated as follows:
A,
Where: Js =Mean flux for the total pile (pCi/m2-s)
J1 =Mean flux measured in region i (pCi/m2-s)
Ar = Area of region i (m2)
A, =Total area of the pile (m2)"
40 CFR 61, Subpart W, Appendix B, Method 115, Subsection 2.1.8, Reporting states "The results of
individual flux measurements, the approximate locations on the pile, and the mean radon tlux for each
region and the mean radon flux for the total stack (pile] shall be included in the emission test report. Any
condition or unusuaJ event that occurred during the measurements that could significantly affect the results
should be reported."
7
9.2 Site Results
Site Specific Sample Resu_lts (reference Appendix C)
(a) The mean radon flux for each region within the site as follows:
Cell 2 -Cover Area 27.7 pCi/m2-s (based on 270,624 m2 area)
Note: Reference Appendix C of this report for the entire summary of individual measurement results.
(b) Using the data presented above, the calculated mean radon flux for each celJ (pjJe) js, as follows:
Cell2 = 27.7 pCi/m2-s
(27.7)(270,624) = 27.7
270,624
As shown above, the arithmetic mean radon flux of the October 2012 samples for Cell 2 at Energy
Fuels White Mesa milling facility is slightly above the NRC and EPA standard of20 pCi/m2-s. The
unusually dry weather which was especially severe in 2012 likely lowered the water table at the site
as well as reducing the moisture content in surface soils. It is believed that this likely increased the
radon flux rates over the previous years' reported results. Appendix C is a summary of individual
measurement results, including blank sample analysis. Sample locations are depicted on Figure 2,
which is included in Appendix D. The map was produced by Tellco.
8
References
U. S. Environmental Protection Agency, Radon Flux Measurements on Gardinier and Royster
Phosphogypsum Piles Near Tampa and Mulberry, Florida, EPA 520/5-85-029, NTIS #PB86-
161874, January 1986.
U.S. Environmental Protection Agency, Title 40, Code of Federal Regulations, July 2012.
U. S. Nuclear Regulatory Commission, Radiological Effluent and Environmental Monitoring at
Uranium Mills, Regulatory Guide 4. I 4, April 1980.
U.S. Nuclear Regul atory Commission, Title 10, Code of Federal Regulations, Part 40, Appendix A,
January 201 2.
9
Figure 1
Large Area Activated Charcoal Canisters Diagram
fiOIIR£ large-ArQ4 Ra~on r.ollettor
10
•O·•~ !$-~
PYCfMC~p
Appendix A
Charcoal Canister Analyses Support Documents
'A
ENERGY FUELS RESOURCES (USA) INC.
WHITE MESA MILL, BLANDING, UTAH
2012 NESHAPs RADON FLUX MEASUREMENTS
SAMPLING DATES: 10/20/12-10/21/12
SYSTEM DATE Bkg Counts {1 min. each)
I. D. #1 #2
M-01/D-21 10/21/2012 127 151
M-01/D-21 10/21/2012 141 142
M-01/D-21 10/22/2012 144 131
M-01 /D-21 10/22/2012 127 150
M-01/D-21 10/21/2012 127 151
M~01/D-21 10/21/2012 141 142
M-01/D-21 10/22/2012 144 131
M-01/D-21 10/22/2012 127 150
M-02/D-20 10/21/2012 148 146
M-02/D-20 10/21/2012 142 151
M-02/D-20 10/2212012 136 124
M-02/D-20 10/2212012 140 126
M-02/D-20 10/21/2012 148 146
M-02/D-20 10/21/2012 142 151
M-02/D-20 10/22/2012 136 124
M-02/D-20 10/22/2012 140 126
#3
136
144
145
153
136
144
145
153
144
142
130
125
144
142
130
125
ACCURACY APPRAISAL TABLE
OCTOBER 2012 SAMPLING
Source Counts (1 min. each) AVG NET
#1 #2 #3 cpm
10346 10395 10371 10233
10416 10147 10201 10112
10404 10253 10350 10196
10214 10160 10429 10124
10140 10206 10309 10080
10223 10312 10195 10101
10247 10295 10206 10109
10154 10438 10236 10133
10603 10586 10569 10440
10318 10498 10302 10228
10593 10247 10490 10313
10454 10361 10520 10315
10271 10230 10242 10102
10178 10366 10350 10153
10316 10254 10461 10214
10332 10186 10255 10127
YIELD FOUND SOURCE
cpm/pCi pCi ID
0.1708 59910 GS-04
0.1708 59206 GS-04
0.1708 59694 GS-04
0.1708 59276 GS-04
0.1708 59018 GS-05
0.1708 59139 GS-05
0.1708 59188 GS-05
0.1708 59325 GS-05
0.1727 60452 GS-04
0.1727 59222 GS-04
0.1727 59718 GS-04
0.1727 59726 GS-04
0.1727 58493 GS-05
0.1727 58790 GS-05
0.1727 59141 GS-05
0.1727 58641 GS-05
AVERAGE PERCENT BIAS FOR ALL ANALYTICAL SESSIONS:
KNOWN %BIAS I
j)Ci
59300 1.0%
59300 -0.2%
59300 0.7%
59300 0.0%
59300 -0.5%
59300 -0.3%
59300 -0.2%
59300 0.0%
59300 1.9%
59300 -0.1%
59300 0.7%
59300 0.7%
59300 -1.4%
59300 -0.9%
59300 -0.3%
59300 -1 .1%
0.0%
CHARCOAL CAN1STER ANALYSIS SYSTEM
SITE LOCATION: W 'v\: k M..<-~ ~ M~ l( 1 B (orc-1 d. [ ,;1.f)) CAT
CLTENT: GVI~~y N ~ Ls 'R-eso'-tV'c.eS:
Calibration Check Log
SystcmlD: ty\.-0{ /t>-2\
ScalcrSIN: t)IS'"t?-
Detector SIN: D L-f I S 3 3
Calibration Date: _ & /0 ~) J I '-Due Date: & / 0 ~
High Voltage: t l k S" Window: 4.42 Thrshld: ____1,2_Q__
Source ID/SN:
Blank Canister Bkgd. Range, cpm: 2 a= II") to
P-~1 '2 -z.. '/G-s "·O'fsourcc Activity: 5~ • 3 K .f-!..t..··
l 5 'S 3 a = l I 0 to I \.:J 7
Gross Source Range, cpm: 2 cr= I 0 oq S"" to t O'f1} .L _ 3 cr = OJ qa, g to i OS/?.>
Technician: V Z-ketv-
All counts times are one minute
Date By Back~ ound Counts (1 min. each) Source Counts (I min. each) ok?
#1 #2 #3 Avg. #I #2 #3 Average YIN
tO h ... • It#--b/J,..n., \'2-7 \51 t3~ t·3g t03Yc, l03~5 I 0'3/f \o'3., I 'I
wi::t.t!t'l.-IP.t~ I '1 I I '12--1'-t ~ lLf-:2-. \O'tlv l o\ '41 t O:l.O/ I OL..Sc;-·v
t<1l.l.i. '· '2-P'4Am-1 LfLI I ''3t 1 't ~ \40 t o~'-f l.0"2-~::1 I o·~s-0 ~0 "3'3 (, 'I
I\Oh-1--/ 11. niJAdA.. i ?-'1 i50 lS3 -~3 l02-14 \0\"'0 l 0 4-2..~ I 02.<PB " f
YIN: Y =average background and source cpm falls within the control limits.
N =average background and source cpm does not fall within the control limits.
The acceptable ranges were detem1ined from prior background and source check data.
l'f'~
ro~t
p \'G.
Vc.'~t
CHARCOAL CAN~STER ANALYSIS SYSTEM
SITE LOCATION: \J\/ Vt; +~ _N\.e Sd'J )A ~ ( (, I J3 ( ~11 dS ~> lA J'"
cLIENT: E:. V' ~ .. <Cl 'f F\.\ e l ~ R.e..f f/ u..'f'u~
Calibration Check Log
10 .tv. -O\ I D ,.., ., System : -"'-V"~'--.L..---=----~---Calibration Date: a? J 0 '1 J I ~ Due Date: ~ / 0~ / I "3
Scaler S/N: 5-I 5 l -:2-. High Voltage:~ 5"' Window: _ _,4"-'.4.::..2 _ Thrsbld: 2.20
Detector SIN: _0_'-f_l_o_~-_3__;3;__ ___ Source ID/SN: () "2 .. ."'1-(,/,._.:::. .. --"'" ~ :y -0 :JSource Activity:
Blank Canister Bkgd. Range, cpm: 2 0' = II "> to \ 5'f::> 3 0' = I I 0 to ( (.,. "2
Gross Source Range, cpm: 2 cr = / 00 SO) to t 0 t.f '2 3 3 cr = '1 C7)(.:, ~ to i 0 S I t...f
Technician: 'P t-~-----
All counts times are one minute
Date By Backg ound Counts (I min. each) Source Counts (I min. each
#1 #2 #3 Avg. #1 #2 #3 Average
l o '.2.o(.. r o 300l l o2L a
YIN: Y =average background and source cpm falls within the control limits.
N =average background and source cpm does not fall within the control limits.
The acceptable ranges were determined from prior background and source check data.
ok?
YIN
CHARCOAL CANISTER ANALYS IS SYSTEM
SITE LOCATION: vJ b J.~ M.e>~~ M ~ \\ 1 'Rifl n d ~~ #' lAT
CUENT: G: V) ~If fJ y F\A ~ l.s 'R ~ s O~G$
Calibration Check Log
System ID: --!...M..~.-_0_~_ . ...L./__::_L7_··_2.__:_:0:::.._ __ Calibration Date: (,; /0 Q) Lc!:_ Due Date: ~· / o " / 1 ""3
Scaler SIN: 6 1 S" I:? 3 High Voltage: ~ 2 5 Window: 4.42 Thrshld: 2.20
Detector SIN: <..?L{ l'~.., v')_ Source ID/SN: t?-c-1 '.2 'l-J, /C?-5 ··. 0 lJ Source Activity: 5 '1· ~ k pC..-
Blnnk Canister Bkgd. Range, cpm: 2 cr = 12-~to _ I 5"2.. 3cr =_j_)7 to_j_~
Gross Source Range, cpm: 2 cr = t 0 2.1 I to l 0 {? o G 3 cr ,., I 0 II 3 to L o ·7 o cj_
Technician: __ )240--.. c:..· --=L-:.... .. __;{);_~-~~'------
All counts times are one minute
Date By Background Counts (I min. each) Source Counts (I min. each) ok?
#l #2 #3 Avg. #I #2 #3 Average YIN
loht J, "2. ,J:I.L.llU. l'fS l '-t(, l Lft.f l41, l Oc,(r~ (05€>C. IOSbO) lDS~ G, ....;
l0/7-t/,....., ~~r~ f (.{ '"'2-151 14 -"J-145 \0~.~ IO'f~S i03o".l. tO ::'37~ y.
toh~n I'D!t/, v ' ~~~ l-:1..4-·~(') t"30 \ QC;'Oj 3 10:2-'4-7 \0~0 10t+43 'I ,o t:~-""J.-/t"-~~---lLtO t2.h l"lG \'30 i 045'+ t03 ~D / ~OS'.J..O t044S' y
YIN: Y =average background and source cpm falls within the eontrollimits.
N =average background and source cpm does not fall within the control limits.
The acceptable ranges were determined from prior background and source check data.
CHARCOAL CANISTER ANALYSIS SYSTEM
s rTELOCATION: -vJ ~;.\-c. M~s~ N\: l\ , 131t7tnA 1 n~ > L{\
CLIENT: ~\'I.e ~\.1 i,h-t l! (5 '8-e.sot.t.{"(..e~
I
Calibration Check Log
System TD: __ M __ -_0_:2.---=--L/---=D:....._-_._2._0__ Calibration Date: __iL_f-0 ~ } P-Due Date:
5'15 ~ -3 ~'25 Scaler SIN:--·-·-------High Voltage: Window: 4.42
~/ot7J)J3
ThrsWd: 2 20
Detector SIN: _ _9. __ '-t 1 5) '").._ 0 '). "%-~ /_..,. • ..-~fl :t ~,<. Source JDISN: f"'V\ I &-5 "O.:>source Activity: _J_='_1_;.)_-F--1
Blank Canister Bkgd. Range, cpm: 2 cr = 1'.1-Y-to I 5""2-3 cr = \I --z to IS"~
Gross Source Range, cpm: 2cr= I OO 3 t to i 0 ft1 (,. 7 3 cr = 9 '3 7 ;1... to I 0 S 2..(p
Technician: ----'b=-='--'/-_' __ ~--+-=;.__-----
All counts times arc one minute
Date By Background Counts (1 min. each) Source Counts (1 min. each) ok?
#1 #2 #3 · Avg. #1 #2 #3 Average YIN
f O('J...I} 1"2. iP.t-c.v~ ~14B 14:~ iU.~ l4t, i o~; J LO::Z.~O t0'2.t..j'2,_ l 0-:2.-Y.R y_
,o(-z..l I.-. '1!7/U,~ I tt "1-I"\"". t l.tl.,... 1 L.fS'" tDf7CO to ~<o(;, I 0'3S'b l 0"2..-0) g v
t0/2 .. -,.fn .. O>tc~ {7, /1 lU l~O 1"30 I 0 '31 <., l0'4Si..f I 04 ee,J I 0'3 Lf4 y
wi~li1-l>L£ .. w.. \UO \2-j.:~ \~ t30 l 0 ?.":a.,").. I Ol 8G? IO''Z-S'S to~-:;-A y
.
YIN: Y =average background and source cpm falls within the control limits.
N = average background and source cpm docs not fall within the control limits.
The acceptable ranges were determined from prior background and source check data.
Appendix B
Recount Data Analyses
8
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: G SURFACE: SOIL
AREA: COVER DEPLOYED: 10 20 12 RETRIEVED: 10
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/021, M021D20 CAL. DUE: 6/10/13
RECOUNT CANISTER ANALYSIS:
AIR TEMP MIN: 39oF
21 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
151 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD PRECISION
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s % RPD
G10
G20
RECOUNT
G40
RECOUNT
G50
RECOUNT
G60
RECOUNT
G70
RECOUNT
G80
RECOUNT
G90
RECOUNT
G100
RECOUNT
G10
G10
G20
G20
G30
G30
G40
G40
G50
G50
G60
G60
G70
G70
G80
G80
G90
G90
G100
GlOO
8 10 8 31 10 21 12 21 6
8 10 8 31 10 22 12 7 50
8 22 8 40 10 21 12 21 14
8 22 8 40 10 22 12 7 50
8 35 8 46 10 21 12 21 21
8 35 8 46 10 22 12 7 51
8 23 8 41 10 21 12 21 29
8 23 8 41 10 22 12 7 51
8 58 9 0 "10-21-12-21 38
8 58 9 0 10 22 12 7 53
8 46 8 51 10 21 12 21 48
8 46 8 51 10 22 12 7 53
9 16 9 11 10 21 12 21 56
9 16 9 11 10 22 1.2 7 54 -----
8 41 8 48 10 21 12 22 6
8 41 8 48 10 22 12 7 55
8 15 8 30 u 21 12 22 15
8 15 8 30 10 22 12 7 58
8 10 8 27 10 21 12 22 24
8 10 8 27 10 22 12 7 58
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
1
2
30494 218 .8
27635 218.8
14497 216.8
13462 216.8
37861 227.8
34177 227.8
29622 215.7
27551 215.7
9501 220-.8
8703 220.8
1715 220.0
1684 220.0
9181 22l .7
8142 221.7
1422 224.1
1302 224.1
1236 -2-04 .-7
1119 204.7
1043 220.7
2051 220.7
45.9
45.1
21.8
21.9
57 .. 5
56.1
44 .8
45.0
4.6
4.5
2 .2
2.2
5.8
5.6
4.5
4.5
n ·--:-3 ___ -1---:-4
14.2 1.4
2.4
2.5
13.9
13.3
0.86
0.83
1.4
1 .4
0.2
0 .3
1.4
1.3
0.1
0.1
0.1
0.1
0.1
0.1
0 .03
0.03
0.03
0.03
0.03
0.03
0.03
0 .03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
1. 8%
0.5%
2.5%
0.4%
0. 7%
4.1%
4.4%
3.6%
5. 7%
0.0%
AVERAGE PERCENT PRECISION FOR THE CELL 2 COVER REGION: 2.4%
Page 1 of 1
Appendix C
Radon Flux Sample Laboratory Data (including Blanks)
c
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: G SURFACE: SOIL
AREA: COVER DEPLOYED: 10 20 12 RETRIEVED: 10
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 39°F
21 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
151 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
G01 G01 8 0 8 23 10 21 12 21 0
0
1
_, __ G02 ' G02· 8 1 8 23 10 21 1.2 2·1
G03 G03 8 2 8 24 10 21 12 21
G04 G04 8 3 8 24 10 21 12 21
-. G05 8 4 8 2 5 10 21 1-2
G07
GOB
Gll
G15
G16
<:i17
G_18.
G19
G20
G23
G24
G'06 8 6 -8 25-10 2'1
G07 8 7 8 30 10 21 12
GOB 8 8 8 30 10 21 12 21
----G.,--0.,..9.,...---'8 .9 8 31 10' 2l L2-21
_ G10 8 iO 8 31 10 21 ·12 21
Gll 8 11 8 32 10 21 12 21
G12 8 13 8 32
di3---8 14 8~
15 8 33
10 21 21
21
10. 21 12. 21
4
4
6
6
8
8
9
9
8 16 8 38 10 21 12 21 11
G16 8 17 8 38 10 21 12 21 11
8 ls 8 ~-101 21 12 2i -12
____ G18 8___12 8 J9 1'0 21 12 21 1-2'
G19 8 21 8 40 10 21 12 2 1 14
G20 8 22 8 40 10 21 12 21 14
G2~1 --an 45 -a 5o 10. 2 1 12 21 15
G22 8 44 8 50 10J .L.12._..11 15
G23 8 43 8 49 10 21 12 21 17
G24 8 42 8 49 10 21 12 21 17
---8 41 8-48 "10 2 1 12 21 18
__;~;;;.;;-;;..;~;...._~----=-~;;;..-.=..~ __ ....;8;.._....;3~9;... _8 ......!.L .]..Q..._21_... 12 2_1 18
G27
G28
G31
G27
G28
G29
G30
G31
G32
8 38 8 47 10 21 12 21 20
8 37 8 47 10 21 12 21 20 8 :36·-8-~---.
8 35 8
8 33 8 45 10 21 12 21
8 32 8 45 10 21 12 21 23
8--3) 8 44 10 2l 12 21 24
a so· a 44 1.0 21 12 21 24
i 2850 21-5 . 1 4 . 1 0 . 4 0 • 0 3
1 25161 214.9 37.9 3.8 0.03 -~-1 1535 218.5 2.1 0.2 0.03
1 30744 219.1 46.3 4.6 0.03
-1 l029 21.7 .7~--~.3 -0.1 0.03
L._ .10'21 2i-~7 1.4 0.1 0.03
1 1802 218.4 2.5 0.3 0.03
1 25484 216.1 38.3 3.8 0.03
1 -2423 220.~8 ---3.5 0.3 0.03 --~~---
1
1
1
1
.1
1
1
1
1
1
1
1
1
1
1
1
l
1
1
1
1
1
1
1
1
6997
28791
9'633
17487
45 .9 4.6 0.03
216.3 10.5 1.0 0.03
219.5 43.4 4 .3 0.03
215.0 14.5 1.5 -0 .. 03
212.9 ~6 .3 2.-6 0.03
8310 215.6 12.5 1.2 0.03
4776 217.8 7.0 0 .7 0.03
26.9'06 --216 .0 n 40.9 4 ":"1 o-.o3
2125§ Q.11.o 32.-o 3.2 o.o2
15945 216.3 24.2 2.4 0.03
14497 216 .8 21.8 2.2 0 .03
14 7 5 2·16 :s 2 ' 6---0 . 2 0 . 0:3:
239'81 217.0 3·6.4 3.6 0.03 ~ ---T -!
1445 217.1 2.0 0.2 0.03
20249 216 .7 30.7 3.1 0 .03
266o~9 2t-6.4 4o.8 -4 :-1 --0.03
25669 217 . ..!..._. -38.9 3. 9 0. 03
4162 217.0 6.2 0 .6 0.03
41814 215.2 63.5 6 .4 0.03
29056 -220 .. 3 ·44.6 ~ 4 .5
3'7861 227.8 57.5
8781 214.8 13.3 1.3
56615 218.6 86.0 8 .6
218 A -14.-4 1.'4
31033 212.8 47.0 4.7
Page 1 of 3
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: G SURFACE: SOIL
AREA: COVER DEPLOYED: 10 20 12 RETRIEVED: 10
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL DUE: 6/10/13
AIR TEMP MIN: 39oF
21 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
151 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
G35
G36
G37
G38
G39
G35
G36
G37
G3'8
G39
G40
8 29 8 43 10 21 12 21 26 1 2786 21608 4ol Oo4 0.03
8 28 8 43 10 21 12 21 26 1 38360 2l8o0 5801 5.8 Oo03
ff 27--~ 4'2 10 2"'ll~ 21 i7 1 n U6Q 9--ii6 • 4 43 • 8 -4-:-'4 --Q • 93
8 25 8 4·2 16 21 12 21 27.. 1 34545 21.906 5203 5 02 0.03 -. . ~ -·· ~ 8 24 8 41 10 21 12 21 29 1 30051 21801 4600 4o6 Oo03
8 23 8 41 10 21 12 21 29 1 29622 215.7 44o8 4o5 Oo03
9 §-9 --8~0-21 12 21 ~1 -1 43661 215 o 5 6'7 A 6 o 7 0 o
~~--9 7 9 8 10 21 12 21 :n 1 1074·9 218'.,3 1602 1.6 0.03
G43 G43 9 6 9 7 10 21 12 21 32 1 10122 223o7 l5o4 1.5 Oo03
G44 G44 9 5 9 7 10 21 12 21 32 1 59191 21701 90o3 9o0 Oo03
G45 --G4S -9 4 9 n_ 6 10 21 12 2l 34 1 ~676·15 221-:l w-104 04 L0-.4 0. 0..,.3-------
G46 . G46 9 3 9 6 10 21 12 2l 34 1 4000 221.'9 5 .9 o:6 Oo03 -----~-----. ---------. . . ;.;;...-------~-G47 G47 9 2 9 1 10 21 12 21 36 1 14649 220 01 2205 2o3 Oo03
G48 G48 9 0 9 1 10 21 12 21 36 1 1886 218 06 2o7 Oo3 Oo03
G49 ---G49 -a-:-s -9 -9--o 10 21 -rr 21 38 -~-1 1.s1ss 22o on 210 9 .....-2 os o:03
..:;G.;;:;5.;;.0_~ __ ...;:G::.:5~0:.._ _ __;;;.8_..;;::5..::.8--=9~·-..::(J~....;l::;.;O::..· ..=~:;,;l:;.._~l.;;:.2_2.1 38 1 9501 22008 _14_.3 1.4 0~0_0_3
G51 G51 8 57 8 59 10 21 1 2 21 40 1 40596 220o7 6207 6 o3 Oo03
56 8 59 10 21 12 21 40 1 14789 22005 2204 202 Oo03
1 " r -14 o sa 2 :l-9 0 7 17-6 . 6 · 17 0 7-.......,o,_o....,o,..,3,..... ___ ~--
~ .'-!~• ,. w• v ~~ _v e-v ~v ~~ ~~ ~~ u ....L...,_n-928 ~21.J. -~ _!8.7 4o9 0.03
G55
G56
G57
q!?'8
G59
G60
G67
G68
G55 8 52 8 53 10 21 12 21 43 1 3964 221.7 5o9 Oo6 0.03
G56 8 51 8 53 10 21 1 2 21 43 1 1 66533 21708 25504 25o5 Oo03
G57 8 -·50 8 ~ 52 'lQ ·21, 12 21-44 1 449'9 5 21'4"':''§----gg:"6-n7"":'"0 Q • 0.3
532.§ 8 ~9-~ _52 _10_2!_._12 21 46 2 ___ -i77_7 2l.4o.1 1.1 0...:.1. ~ 0.03
G59 8 48 8 51 10 21 12 21 49 2 1682 220o8 1.1 0 01 Oo03
G60 8 46 8 51 10 21 12 21 48 1 1715 22000 204 Oo2 0.03
G~1 9 10 9 9 10 21 12 21 51 1 .. -53~1-215.9 ~ 8n.O 00~8--0-.-0-3-~--------,
~62 -___ 9 _11_ ~ -9 _ _1..2;_2_1 _1_2_ 21 51 1 4843 218 0! ___ 7 02=--~~=0~! 7!.-.· ~--:.O..:.o.;.0;;;,3 ____ ---'~-
G63 9 12 9 10 10 21 12 21 52 1 2899 2l8o2 4o3 Oo4 Oo03
G64 9 13 9 10 10 21 12 21 52 1 60882 21503 93o4 9o3 Oo03
~---.,G65 -........ 9 1 4 9 -11 10 2i 12 2i 53 i 21907 21606 --33 08 -3-:4"--o.,..._....,o,..,3--~--~---,
~6_6 9 . 16 .9 11 10 21 12 21 53 1 -~3204 21J. 7 --35 0 5 3. 6 0. 03
G67 9 17 9 12 1 0 21 12 21 55 1 17439 217ol 2609 207 Oo03
G68 9 18 9 12 10 21 12 21 55 1 3672 22301 5o4 Oo5 Oo03
Page 2 of 3
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: G SURFACE: SOIL
AREA: COVER DEPLOYED: 10 20 12 RETRIEVED: 10
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
AIR TEMP MIN: 39•F
21 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
151 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
G69
G70
G71
G72
G73
G74
G75
G76
G77
G78
G79
G80
G81
I G82
G83
G84
G85
G86
G87
G88
G89
G90
G91
G97
G98
G99
G100
G69 9 18 9
G70 9 16 9
G71 9 14 9
G72 9 12 9
G73 9 10 9
G74 9 8 9
G75 9 6 9
G76 9 4 9
G77 8 35 8
G78 8 37 8
G79 8 39 8
G80 8 41 8
G81 8 43 8
G82 8 45 8
G83 8 47 8
G84 8 49 8
G85 8 51 8
Ga..§___ _a_ 53 a
G87 8 55 8
G88 8 57 8
G89 -8 13 8
G90 8 1.5 8 ---G91 8 17 8
G92 8 19 8
G93 8 21 8
G94 8 23 8
G95 8 26 8
G96 8 28 8
G97 --8 -30 8
12 10 21 12 21
11 10 21 12 21
9 10 21 12 21
8 10 21 12 21
7 10 21 12 21
5 10 21 12 21
4 10 21 12 22
3 10 21 12 22
44 10 2T 12 22
45 10 21 1.? 22
46 10 21 12 22
48 10 21 12 22
49 10 2-1-12 22
so 10 21. 12 22
52 10 21 12 22
53 10 21 12 22
54 10 -2'1 TI 22
56 10 2 ;1 12 22
57 10 21 12 22
58 10 21 12 22
29 10 2 l 12 22
30 10 21 12 22 ---31 10 21 12 22
33 10 21 12 22
34 10 21 12 22
35 10 21 12 22
37 10 21 12 22
38 10 21 12 22
39 10 21 12-22
56
56
58
58
59
59
1
1
2
3
5
6
8
8
10
10
11
11
12
12
14
15
18
17
20
20
21
21
23
G98 B 0 8 25 1_9_21 1~ 22 23
G99
GlOO
8
8
7 8 26 10 21 12 22 24
10 8 27 10 21 12 22 24
1 4825
1 9181
1 16841
1 24565
1 5665
1 13117
1 1374
1 1314
1 43794
2 1577
1 4083
2 1422
1 SllO
1 20896 ---1 21298
1 2376
1 -~--4500
1 !:)548
1 3165
1 6027
1 -4'285
2 1236
2 1625
1 2232
1 6642
1 4384
1 2475
1 4840
1 27993
221.1
221.7
221.9
222.0
215.9
222.4
225 .2
222.1
217.9
218.6
216.6
224.1
218.7
222.5
220.8
220.9
224.1
223 .1
215.3
221.3
220 .6
204.7
219.0
221.5
224.6
221.1
224.6
220.4
220.9
1
1
1
2403 215.9
1255 216.1
1043 220.7
AVERAGE RADON FLUX RATE FOR THE CELL 2 COVER REGION:
Page 3 of 3
7.3
13 .9
26 .0
37.6
8.6
20.0
1.9
1 .8
67 .7
1.0
6.1
0.9
7.7
31.9
32.9
3.4
6.8
8.3
4 .7
9 .1
6.4
0.7
1.0
3.2
10.1
6.5
3.6
7 .2
43:3
0.7
1.4
2.6
3.8
0 .9
2.0
0.2
0.2
6.8
0.1
0.6
0.1
0.8
3.2
3.3
0.3
0.7
0.8
0.5
0.9
0.6
0 .1
0.1
0.3
1.0
0.7
0.4
0.7
4.3
14.1 1. 4
1.7 0.2
1.4 0.1
27.7 pCi/m2 s
0 .03
0.03
0.03
0.03
0.03
0.03
0 .03
0.03
0.03
0.03
0.03
0.03
0 .03
0.03 --~~-~~ 0.03
0.03
0.03
0.0~3 ____________ __
0.03
0 .03
0.03
0.03
0.03
0.03
0.03
0.03
0 .03
0.03
0 .03
0.03
0.03
0.03
CLIENT: ENERGY FUELS RESOURCES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: G SURFACE: SOIL
AREA: COVER DEPLOYED: 10 20 12 RETRIEVED: 10
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/10/13
BLANK CANISTER ANALYSIS:
AIR TEMP MIN: 39"F
21 12 CHARCOAL BKG:
DATA ENTRY BY: DLC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
151 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
G BLANK 1 G BLANK 1 7 30 8 10 10 21 12 18 28 10 1877 205 .7 0 .05 0.02 0.03 CONTROL
_s;_?~K 2 G BLANK 2 7 30 8 1<2..._10 2], 12 18 28 10 1820 205 .5 0 .05 0.02 0.03 CONTROL
G BLANK 3 G BLANK 3 7 30 8 10 10 21 12 18 41 10 1806 207.5 0.04 0.02 0.03 CONTROL
G BLANK 4 G BLANK 4 7 30 8 10 10 21 12 18 41 10 1814 207.8 0.04 0 .02 0.03 CONTROL
G ·BLANK 5 G BLANK 5 7 30 8 10 10 21 i2 18 -55 10 1883 207.6 0. 0"6 o""":o2 0.03 CONTROL
AVERAGE BLANK CANISTER ANALYSIS FOR THE CELL 2 COVER REGION: 0 .05 pCi/m2 s
Page 1 of 1
Appendix D
Sample Locations Map (Figure 2)
D
·C£U.1•
002 .... ... GoS 0: 001 ... GOt G10 "" ... ... G1• 0 0 0 0 0 0 0 0 0 0 0 0
..,, G>l .,. "" '66 ~ ...,. "" ""' "" .... .... Q6 ..... 0 0 0 0 0 0 0 0 0 0 0 0 -<l>Y!><l>OlGlOH-....... GS1 GSO .... c;,. 46' .. , G51 6SO "&' ... ""' Goo$
0 0 0 0 0 0 0 0
-<lUl-
G1> G'f} ·~ .,., "&' G60 G07 GOO ...
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WHITE MESA MILL
BLANDING. UTAH
NESHAPS 201 2
OCTOBER 2012 SAMPUNG
PREPARED FOR
ENERGY FUELS RESOURCES
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Letter to B. Bird
March 29,2013
Page 14 of 15
ATTACHMENT lD
Tellco Report on Annual Radon Flux Monitoring
November 2012
National Emission Standards for Hazardous Air Pollutants
2012 Radon Flux Measurement Program
White Mesa Mill
6425 South Highway 191
Blanding, Utah 84511
November 2012 Sampling Results
Prepared for: Energy Fuels Resources (USA) Inc.
6425 S. Highway 191
P.O. Box 809
Blanding, Utah 84511
Prepared by: Tellco Environmental
P.O. Box 3987
Grand Junction, Colorado 81502
TABLE OF CONTENTS
Page
1. INTRODUCTION ........................................................................................................................... 1
2. SITE HISTORY AND DESCRIPTION .......................................................................................... 1
3. REGULATORY REQUIREMENTS FOR THE SITE .................................................................... 2
4. SAMPLING METHODOLOGY ..................................................................................................... 2
5 .. FIELD OPERA TlONS .................................................................................................................... 3
5.1 Equip1nent Preparation ....................................................................................................... 3
5.2 Sample Locations, Identification, and Placement ............................................................. 3
5.3 Sample Retrieval ............................................................................................................... 4
5.4 Environmental Conditions ................................................................................................ 4
6. SA.MPLE ANALYSIS ..................................................................................................................... 4
6.1 Apparatus ........................................................................................................................... 4
6.2 Sample Inspection and Documentation ............................................................................. 4
6.3 Background and Sample Counting .................................................................................... 5
7. QUALITY CONTROL (QC) AND DATA VALIDATION ........................................................... 5
7.1 Sensitivity .......................................................................................................................... 5
7.2 Precision ............................................................................................................................. 6
7.3 Accuracy ............................................................................................................................ 6
7.4 Co1npleteness ..................................................................................................................... 6
8. CALCULATIONS ........................................................................................................................... 6
9. RESULTS ........................................................................................................................................ 7
9.1 Mean Radon Flux ............................................................................................................... 7
9.2 Site Results ......................................................................................................................... 8
References ............................................................................................................................................ 9
Figure 1 .............................................................................................................................................. 10
Appendix A. Charcoal Canister Analyses Support Documents
Appendix B. Recount Data Analyses
Appendix C. Radon Flux Sample Laboratory Data, Including Blanks
Appendix D. Sample Locations Map (Figure 2)
i
1. INTRODUCTION
During November J 9-20, 2012, Tellco Environmental, LLC (Tellco) of Grand Junction, Colorado,
provided support to Energy Fuels Resources (USA) Inc. (Energy Fuels) to conduct additional radon
flux measurements regarding the required National Emission Standards for Hazardous Air Pollutants
(NESHAPs) Radon Flux Measurements. These measurements are required of Energy Fuels to show
compliance with Federal Regulations (further discussed in Section 3 below). The standard is not an
average per facility, but is an average per radon source. The standard allows mill owners or operators
the option of either making a single set of measurements or making measurements over a one year
period (e.g., weekly, monthly, or quarterly intervals).
Radon flux measurements were Initially performed in June 2012 on Cell 2 and Cell 3 with the
intention of performing a single set of measurements to represent the year 2012 as allowed by the
regulations (Method 115). The results of the June 2012 sampling (presented in a separate repmt)
measured an arithmetic average radon flux rate of 23.1 picoCuries per square meter per second
(pCi/m2-s) for Cell 2 and 18.0 pCi/m2-s for Cell 3. Because the results for Cell 2 exceeded the
regulatory standard of 20 pCilm2-s, Energy Fuels directed Tellco to perform additional radon flux
measurements of Cell 2 in September, October, and Novembet' 2012. This repott addresses the results
of the November 2012 sampling while the June, September) and October 2012 sampling results are
each presented in separate reports. No additional sampling of Cell 3 was performed because the
avet•age radon flux rate measured by the June 2012 sampling was below the regulatory standard.
Tellco was contracted to provide radon canisters, equipment, and canister placement personnel as well
as lab analysis of samples for calendar year 2012. Energy Fuels personnel provided support for
loading and lmloading charcoal from the canisters. This report includes the procedures employed by
Energy Fuels and Tellco to obtain the results presented in Section 9.0 of this report.
2. SITE DESCRIPTION
The White Mesa Mill facil ity is located in San Juan County in southeastern Utah, six miles south of
Blanding1 Utah. The mill began operations in 1980 for the purpose of extracting uranium and
vanadium from feed stocks. Processing effluents from the operation are deposited in four lined cells,
which vary in depth. Cell l, Cell 4A, and Cell 4B did not require radon flux sampling, as explained in
Section 3 below.
Cell 2, which has a total area of approximately 270,624 square meters (m2), has been filled and
covered with interim cover. This cell was comprised of one region; a soil cover of varying thickness,
which required NESHAPs radon flux monitoring. The Cell 2 cover region was the same size in 2012
as it was in 201 I. There were no exposed tailings or standing liquid within Cell 2.
Cell 3, which has a total area of 288,858 m2, is nearly filled with tailings sand and is undergoing pre-
closure activities. This cell was comprised of two source regions that required NESHAPs radon
monitoring: at the time of the June 2012 radon sampling, approximately 219,054 m2 of the cell had a
soil cover of varying thickness and approximately 36,233 m2 of exposed tailings "beaches". The
remaining approximately 33,571 m2 was covered by standing liquid in lower elevation areas. The
1
standing liquid area was much smaller than in 201 I. Raffinate crystals and residue from the repair of
the original Cell 4A in 2006 have been placed in Cell 3.
The Cell 3 cover region area was larger during the 2012 radon flux sampling than it was for the 2011
sampling program. Due to worker health and safety concerns by both Energy Fuels and Tellco
personnel, portions of the unstable and wet beaches and covered areas were not sampled. The areas
tested for radon emanation are representative of the disposition of tailings for the 2012 reporting
period.
3. REGULATORY REQUIREMENTS FOR THE SITE
Radon emissions fi:om the uranium mill tailings at this site are regulated by the State of Utah's
Division of Radiation Control and administered by the Utah Division of Air Quality under generally
applicable standards set by the Environmental Protection Agency (EPA) for Operating Mills.
Applicable regulations are specified in 40 C FR Part 61, Subpart W, National Emission Standards for
Radon Emissions from Operating Mill Tailings, with technical procedures in Appendix B. At present,
there are no Subpart T uranium mill tailings at this site. These regulations are a subset of the
NESHAPs. According to subsection 61.252 Standard, (a) radon-222 emissions to ambient air from an
existing uranium mill tailings pile shall not exceed an average of20 picoCuries per square meter per
second (pCi/m2-s) for each pile or region. Subsection 61.253, Determining Compliance, states that:
"Compliance with the emission standard in this subpart shall be determined annually through the use
ofMethod 115 of Appendix B." The repaired Cei1 4A, and newly constructed Cell4B, were both
constructed after December 15, 1989 and each was constructed with less than 40 acres surface area.
Cell 4A and 4B comply with the requirements of 40 CFR 61.252(b), therefore no radon flux
measurements are requi red on either Cell 4A or 4B.
4. SAMPLING METHODOLOGY
Radon emissions were measured using Large Area Activated Charcoal Canisters (canisters) in
conformance with 40 CFR, Part 61, Appendix. B. Method 115, Restrictions to Radon Flux
Measurements, (EPA, 2012). These are passive gas adsorption sampling devices used to determine
the flux rate of radon-222 gas from a surface. The canisters were constructed using a 1 0-inch
diameter PVC end cap containing a bed of 180 grams of activated, granular charcoal. The prepared
charcoal was placed in the canisters on a supp01t grid on top of a Y:z incr thick layer of foam and
secured with a retaining ring under I Y:z inches of foam (see Figure l, page I I).
One hundred sampling locations were distributed throughout Cell 2 (which consisted of one region) as
depicted on the Sample Locations Map (see Figure 2, Appendix D). Each charged canister was placed
directly onto th e surface (open face down) and exposed to the surface for 24 hours. Radon gas
adsorbed onto the charcoal and the subsequent radioactive decay of the entrained radon resulted in
radioactive lead-214 and bismuth-214. These radon progeny isotopes emit characteristic gamma
photons that can be detected through gamma spectroscopy. The original total activity of the
adsorbed radon was calculated from these gamma ray measurements using calibration factors
derived from cross-calibration of standard sources containing known total activities of radium-226
with geometry identical to the counted samples and from the principles of radioactive decay.
After 24 hours, the exposed charcoal was transfetTed to a sealed plastic sample container (to prevent
radon loss and/or further exposure during transport), identified and labeled, and transported to the
2
Tellco laboratory in Grand Junction, Colorado for analysis. Upon completion of on-site activities, the
field equipment was alpha and beta-gamma scanned for possible contamination resulting from
fieldwork activities. All field equipment was surveyed by Energy Fuels Radiation Safety personnel
and released for unrestricted use. Tellco personnel maintained custody ofthe samples from coJlection
through analysis.
5. FIELD OPERATIONS
5.1 Equipment Preparation
All charcoal was dried at 11 0°C before use in the field. Unused charcoal and recycled charcoal were
treated the same. I 80-gram aJiquots of dried charcoal were weighed and placed in sample containers.
Proper balance operation was verified daily by checking a standard weight. The balance readout
agreed with the known standard weight to within ± 0.1 percent.
After acceptable balance check, empty containers were individually placed on the balance and the
scale was re-zeroed with the container on the baJance. Unexposed and dried charcoal was carefully
added to the container until the readout registered 180 grams. The lid was immediately placed on the
container and sealed with plastic tape. The balance was checked for readout drift between readings.
Sealed containers with unexposed charcoal were placed individuaJiy in the shielded counting well,
with the bottom of the container centered over the detector, and the background count rate was
documented. Three five-minute background counts were conducted on ten percent of the containers,
selected at random to represent the "batch". If the background counts were too high to achieve an
acceptable lower limit of detection (LLD), the entire charcoal batch was labeled non-conforming and
recycled through the heating/drying process.
5.2 Sample Locations, Identification1 and Placement
On November 19, 2012, the sampling locations were spread out throughout the CeJI 2 region. The
same original designated sample point locations that were established for the June 2012 sampling of
Cell 2 were used for the October sampling. A sample identification number (ID) was assigned to
every sample point, using a sequential alphanumeric system indicating the charcoal batch and physical
location within the region (e.g., 101 ... I 1 00). This ID was wdtten on an adhesive label and affixed to
the top of the canister. The sample JD, date, and time of placement were recorded on the radon flux
measurements data sheets for the set of one hundred measurements.
Prior to placing a canister at each sample location, the retaining ring, screen, and foam pad of each
canister were removed to expose the charcoal support grid. A pre-measured charcoal charge was
selected from a batch, opened and distributed evenly across the support grid. The canister was then
reassembled and placed face down on the surface at each sampling location. Care was exercised not
to push the device into the soil surface. The canister rim was "sealed" to the surface using a berm of
local borrow material.
Five canisters (blanks) were similarly processed and the canisters were kept inside an aittight plastic
bag during the 24-hour testing period.
3
5.3 Sample Retrieval
On 1\lovember 20, 2012 at the end of the 24·hour testing period, all canisters were retrieved,
disassembled and each charcoal sample was individually poured through a funnel into a container.
Identification numbers were transferred to the appropriate container, which was sealed and placed in a
box for transport. Retrieval date and time were recorded on the same data sheets as the sample
placement information. The blank samples were similarly processed.
During the retrieval process, two of the canisters (I 15 and 148) placed throughout the Cell 2 sampling
region were dropped, spilling the charcoal samples from those ca11isters. The charcoal samples from
the remaining 98 canisters were successfully containerized during the unloading process.
5.4 Environmental Conditions
A rain gauge was in place at the Whjte Mesa Mill site to monitor rainfall and air temperatures during
sampling in order to ensure compliance with the regulatory measurement criteria.
In accordance with 40 CFR, Patt 61 , Appendix B, Method 115:
• Measurements were not initiated within 24 hours of rainfall.
• No rainfall occurred during any of the sampling periods.
6. SAMPLE ANALYSIS
6.1 Apparatus
Apparatus used for the analysis:
• Single-or multi-channel pulse height analysis system, Ludlum Model 2200 with a
Teledyne 3" x 3" sodium iodide, thallium-activated (Nai(Tl)) detector.
• Lead shielded counting well approximately 40 em deep with 5-cm thick lead walls and a 7-
cm thick base and 5 em thick top.
• National Institute of Standards and Technology (NIST) traceable aqueous solution radium-
226 absorbed onto 180 grams of activated charcoal.
• Ohaus Model C501 balance with 0.1-gram sensitivity.
6.2 Sample Inspection and Documentation
Once in the laboratory, the integrity of each charcoal container was verified by visual inspection of the
plastic container. Laboratory staff documented damaged or unsealed containers and verified that the
data sheet was complete.
All of the 98 sample containers and 5 blank containers received and inspected at the Tellco analytical
laboratory were verified as valid.
4
6.3 Background and Sample Counting
The gamma ray counting system was checked daily, including background and radium-226 source
measurements prior to and after each counting session. Based on calibration statistics, using two
sources with known radium-226 content, background and source control limits were established for
each LudlumfTeledyne counting system with shielded well (see Appendix A).
Gamma ray counting of exposed charcoal samples included the following steps:
• The length of count time was determined by the activity of the sample bei11g analyzed,
according to a data quality objective of a minimum of I ,000 accrued counts for any given
sample.
• The sample container was centered on the Nat detector and the shielded well door was
closed.
• T he sample was counted over a determined count length and then the mid-sample cotUlt
time, date, and gross counts were documented on the radon flux measurements data sheet
and used in the calculations.
• The above steps were repeated for each exposed charcoal sample.
• Approximately 1 0 percent of tl1e containers counted were selected for recounting. These
containers were recOlmted within a few days following the original count.
7. QUALITY CONTROL (QC) AND DATA VALIDATION
Charcoal flux measurement QC samples included the following intra~Iaboratory analytical frequency
objectives:
• Blanks, 5 percent, and
• Recounts, 10 percent
All sample data were subjected to validation protocols that included assessments of sensitivity,
precision, accuracy, and completeness. All method-required data quality objectives (EPA, 2012) were
attained.
7.1 Sensitivity
A total of five blanks were analyzed by measuring the radon progeny activity in samples subjected to
all aspects of the measurement process, excepting exposure to the source region. These blank sample
measurements comprised approximately 5 percent of the field measurements. The results ofthe blank
sample radon flux rates ranged from 0.02 to 0.04 pCi/m2 -s, with an average of approximately 0.03
pCi/m2-s.
7.2 Precision
Ten recount measurements, distributed throughout the sample set, were performed by replicating
analyses of individual field samples (see Appendix B). These recount measurements comprised
approximately 10 percent of the total number of samples analyzed. The precision of all recount
5
measurements, expressed as relative percent difference (RPD), ranged from less than 1 percent to 9.5
percent with an overall average precision of approximately 3.8 percent.
7.3 Accuracy
Accuracy of field measurements was assessed daily by counting two laboratory control samples with
known Ra-226 content. Accuracy of these lab control sample measurements, expressed as percent
bias, ranged from approximately -2.5 percent to +2.5 percent. The arithmetic average bias of the lab
control sample measurements was approximately -0.3 percent (see Appendix A).
7.4 Completeness
Ninety-eight samples from the Cell 2 Cover Region were verified, representing 98 percent
completeness for the November 2012 radon flux sampling.
8. CALCULATIONS
Radon flux rates were calculated for charcoal collection samples using calibration factors derived
from cross-calibration to sources with known total activity with identical geometry as the charcoal
containers. A yield efficiency factor was used to calculate the total activity of the sample charcoal
containers. Individual field sample result values presented were not reduced by the results ofthe field
blank analyses.
In practice, radon flux rates were calculated by a database computer program. The algorithms utilized
by the data base program were as follows:
Equation 8.1:
where:
pCi Rn-222/m2sec = [Ts* A *b*~.S(d/91.15)]
N
Ts
b
d
A
=net sample count rate, cpm under 220-662 keV peak
= sample duration, seconds
= instrument calibration factor, cpm per pCi; values used:
0.1708, forM-01/D-21 and
0.1727, forM-02/D-20
=decay time, elapsed hours between sample mid-time and count mid-time
= area of the canister, m2
Equation 8.2:
Gross Sampl e , cpm Bac kground Sampl e, cpm + Sampl eCount ,t ,min Ba ckground Count,t,min Error,2cr = 2x -'-------------------x Sampl e Concentration
Net ,cpm
6
Equation 8.3:
LLD = [~:; A+*b;g:s1f~~~s1)
where: 2.71 == constant
4.65 =confidence interval factor
sb =standard deviation of the background count rate
Ts =sample duration, seconds
b =instrument calibration factor, cpm per pCi; values used:
0.1708, for M-01/D-21 and
0.1727, for M-02/D-20
d =decay time, elapsed hours between sample mid-time and count mid-time
A =area of the canister, m2
9. RESULTS
9.1 Mean Radon Flux
Referencing 40 CFR, Part 61, Subpart W, Appendix B, Method 115 -Monitoring for Radon-222
Emissions, Subsection 2.1.7 -Calculations, ''the mean radon flux for each region of the pile and for
the total pile shall be calculated and reported as fo llows:
(a) The indiv idual radon flux calculations shall be made as provided in Appendix A EPA
86(1). The mean radon flux for each region ofthe pile shall be calculated by summing all
indjvidual flux measurements for the region and dividing by the total number of flux
measurements for the region.
(b) The mean radon flux for the total uranium mill tailings pile shall be calculated as fo1lows:
At
Where: J5 =Mean flux for the total pile (pCi/m2-s)
Ji =Mean flux measured in region i (pCi/m2-s)
Ai =Area of region i (m2)
At =Total area of the pile (m2r
40 CFR 61, Subpart W, Appendix B, Method 115, Subsection 2.1.8, Reporting states "The results of
individual flux measurements, the approximate locations on the pile, and the mean radon flux for each
region and the mean radon fl'-'x for the total stack [pile] shall be included in the emission test report. Any
condition or unusual event that occurred during the measurements that could significantly affect the results
should be reported."
7
9.2 Site Results
.Site Specific Sample Results (reference Appendix C)
(a) The mean radon tlux for each region within the site as follows;
Celt 2 -Cover Area = 26.1 pCi/m2-s (based on 270,624 m2 area)
Note: Reference Appendix C of this report for the entire summary of individual measurement results.
(b) Using the data presented above, the calculated mean radon flux for each cell (pile) is, as follows:
Cell2 = 26.1 pCi/m2-s
(26.1 )(270,624) = 26.1
270,624
As shown above, the arithmetic mean radon flux of the November 2012 samples for Cell 2 at
Energy Fuels White Mesa milling facility is slightly above the NRC and EPA standard of 20
pCi/m2-s. The unusually dry weather which was especially severe in 2012 likely lowered the water
table at the s ite as well as reducing the moisture content in surface soils. Jt is believed that this
likely increased the radon flux rates over the previous years' reported results. Appendix C is a
summary of individual measurement resuJts, including blank sample analysis. Sample locations are
depicted on Figure 2, which is included in Appendix D. The map was produced by Tellco.
8
References
U. S. Environmental Protection Agency, Radon Flux Measurements on Gardinier and Royster
Phosphogypsum Piles Near Tampa and Mulberry, Florida, EPA 520/5-85-029, NTIS #PB86-
161874, January 1986.
U. S. Environmental Protection Agency, Title 40, Code of Federal Regulations, July 2012.
U. S. Nuclear Regulatory Commission, Radiological Effluent and Environmental Monitoring at
Uranium Mills, Regulatory Guide 4.14, AprH 1980.
U.S. Nuclear Regulatory Commission, Title 10, Code ofFederal Regulations, Part 40, Appendix A,
January 2012.
9
Figure 1
Large Area Activated Charcoal Canisters Diagram
fJGUR[
10
10··~ ~~
PYC EMC~p
Appendix A
Charcoal Canister Analyses Support Documents
A
ENERGY FUELS RESOURCES
WHITE MESA MILL, BLANDING, UTAH
2012 NESHAPs RADON FLUX MEASUREMENTS
SAMPLING DATES: 11/19/12-11/20/12
SYSTEM DATE Bkg Counts (1 min. each)
I. D. #1 #2
M-01/D-21 11/21/2012 153 147
M-01 /D-21 11/21/2012 155 152
M-01 /D-21 11/22/2012 155 126
M-01/D-21 11/22/2012 151 139
M-01/D-21 11/21/2012 153 147
M-01/0-21 11/21/2012 155 152
M-01/D-21 11/22/2012 155 126
M-01/D-21 11/22/2012 151 139
M-02/D-20 11/21/2012 126 143
M-02/D-20 11/21/2012 129 144
M-02/D-20 11/22/2012 138 141
M-02/D-20 11/22/2012 125 138
M-0210-20 11/21/2012 126 143
M-02/D-20 11/21/2012 129 144
M-02/0-20 11/22/2012 138 141
M-02/0-20 11/2.2/2012 125 138
#3
154
146
150
137
154
146
150
137
142
136
145
129
142
136
145
129
ACCURACY APPRAISAL TABLE
NOVEMBER 2012 SAMPLING
Source Counts (1 min. each)
#1 #2 #3
10215 10296 10253
10333 10279 10301
10132 10157 10101
10303 10114 10132
10287 10274 10238
10347 10270 10318
10215 10066 10069
10313 10331 10141
10307 10313 10268
10241 10240 10228
10572 10433 10489
10553 10561 10495
10096 10040 10071
10197 10058 10162
10594 10187 10453
10483 10599 10624
AVG NET YIELD FOUND SOURCE
cpm cpm/pCi pCi ID
10103 0.1713 58980 GS-04
10153 0.1713 59272 GS-04
9986 0.1713 58297 GS-04
10041 0.1713 58615 GS-04
10115 0.1713 59048 GS-05
10161 0.1713 59315 GS-05
9973 0.1713 58219 GS-05
10119 0.1713 59074 GS-05
10159 0.1718 59133 GS-04
10100 0.1718 58789 GS-04
10357 0.1718 60283 GS-04
10406 0.1718 60568 GS-04
9932 0.1718 57811 GS-05
10003 0.1718 58223 GS-05
10270 0.1718 59779 GS-05
10438 0.1718 60757 GS-05
AVERAGE PERCENT BIAS FOR ALL ANALYTICAL SESSIONS:
KNOWN %BIAS
pCi
59300 -0.5%
59300 0.0%
59300 -1.7%
59300 -1.2%
59300 -0.4%
59300 0.0%
59300 -1.8%
59300 -0.4%
59300 -0.3%
59300 -0.9%
59300 1.7%
59300 2.1%
59300 -2.5%
59300 -1.8%
59300 0.8%
59300 2.5%
-0.3%
CHARCOAL CANISTER ANAL YSlS SYSTEM
SITE LOCA TlON: 'vV ~ ·, \-e tv\ t' ~ ~ M \ 1.1, u I V\ Vl d : 1'\~ I l.{T
cLIENT: 'EV'I-ef~'f E'--\-f\5 R-<.'.sowrc.es
Calibratjon Checlc Log
System TO: __:__t'/l_-Q=-1....!./_t>..:..__-_2-_l __ _ Calibration Date: (j / 00 /! ""2-, Due Date: ~ / 010 /t 3
4.42 Thrshld: 2.20 Scaler SIN: 5 151 '?-.
Detector SIN: 0 l.f-1 5 3·3
High Voltage: I I '). 5 Window:
0 _"2-1-1,;/
Source lL>/SN: ·~ I GS-'D 4_ Source Activity: 5t:y • 3 it.. p {.;j
Blank Canister Bkgd. Range, cpm: 2 cr = _ ..... l..:..I...Lq ___ to --'--1 :::.5'_B=:..__ 3 o = ll 0 10 I ~ 7
Gross Source Range, cpm: 2 cr= t 0 OlilS to 1 O'-t-<0 I
·rechnician: J2k ~,r:=:::
3cr= 01">9 B to l0578
All counts times are one minute
Date By Backg ·ound Counts ( 1 min. each) Source Counts (I min. each) ok?
#I #2 113 Avg. #l #2 #13 Average YIN
\1 f2.!) I '?... .,, /. ..... I c:;-3 \~'/ tS"L.f I '3 I ft')"LI ~ I n·?~OII ... r 0'?~<"1 10?_c;-5 _'L_
11/z.i /t-:1-11:>7/..,... l5c:) t<)'2 14C.. It:-I 1 0~3~ t0'2,./Q 1 n "3ol 10 30'+ ...,
ll/~0-b/~ tS~ I :l... <.t, I 'i"'O 14Ll t()\ ~:2 I 01 t::;4 r61o/ T OI30 4
tt'J'2.i.J C'l. lh/ ",J)" \51 t3~ L37 1·4'i 10'303 Jo\Tlf To\~2 !otH3 y
I
-
YIN: Y = avemge background and source cpm falls within the controlltmits.
N = nvernge background and source cpm docs not fall within the control limits.
The acceptable ranges were determined from prior background and source check data.
CHARCOAL CANISTER ANALYSIS SYSTEM
siTE LOCATION: \fJ h :.\--c M.. e s ti\. \"\ t ({ 1 t3 ( t7t "' d. ~. V\. .j 7 L{ T
CLIENT: f;v-. e.v-'1~ ~\.{ < \s R ~ .So~vt.c~c c-s
Calibration Check Log
System ID: ___,f!\...__M_'O_I,I-/_J?~--7-_I __ _ Calibration Date: ~/00 J I "'2... Due Date: ~ / 0~ J I J
Scaler SIN: --=~::::c.-_1 5_:__7:........::.2-_____ High Voltage: II '25 Window: 4.42 Thrshld: 2.20
Detector SIN: _o_Lf_:__l 5.::...._3---=-3 ____ Source fD/SN: ~"2.:1-tJ. /6-S-p .$ Source Activity: s-q, 3 K ~ Li
Blank Canister Bkgd. Range, cpm: 2 0" =_----=--l _I _,OJ'---to _ ___::lc...::S':.-8_ 3 a = _ _,(~l:..._O:..__ to __ l....:;h_·7 __
2 cr = l 0 0 5 ~ to l 0 '{ 43 3 cr e 0 7 & B lo I 0 s I 'I Gross Source Range, cpm:
Technician: VZ-?~ ---'-----'---
All counts times are one minute
Date By Backg ound Counts (1 min. each) Source Counts (I min. each) ok?
#1 #2 #3 Avg. #I #2 #3 Average YIN
\ 1}?-1 }11 ~l.!Ao. l 53 IY"' ls _<t_ 1 ~1 l 02.f67 I 0"271.-f l 02~B 10?-.i.:f.::. y
\t/7.-,/n-ll;»~ ~\55 I ~ I q ~ t5"1 I C>~£.4 7 t ():l. 70 103/'B \ 031'?-~
II}:J:J-I ( 2 ~~ 1 s-s t 2 J,, L ")0 I t.; '-f 1021< I 00 fn(,; to o~~ \0 I i ·7 'y'
1\j}-.""J,-/1'2... D'J.-.. I "5'" l \ -:l.Ol 131 IY?-IC"?t3 L D '3:> 3' t o J 41 IO.:.:t<.:.~ -;
YIN: Y =average background and source cpm falls within the control limits.
N • average backgrow1d and source cpm does not faU within the control limits.
The acceptable ranges were dete1mined from prior background and source check dala.
Pre
fo~
f'f"(
r>o~+
CHARCOAL CANISTER ANALYSIS SYSTEM
siTE LOCATION: \N ~~k M eS&\ M: l( , '61 ""'"" J ,t ~ ) L{ T
CLIENT: 'E. V\ C v-~ :7 ~ 1-\ ~ \ "'> \Z e S o v.. V" C...~ S
Calibration Check Log
"" -o~-:--. ·-~o "·J o o. ) ,..., System ID: --!.IV~ l __ -:!:LL-v __ .... _____ Calibration Date: V' -, '-Due Date:
Scaler SIN: ---'~~f_S"_v_3 _____ High Voltage: B 2-s-Window: _..;:!4-'..:::!.4:.2 _ Thrsbld: __,2""'.2"""0'---
Detector SIN: 0 lf I 5 3 2-Sourcc JD/SN: 'R ~ z<-b /cj-5-0 tf
I Source Activity: G" 0 . 3 k. f(J
Blank Canister Bkgd. Range, cpm: 2 cr = _.Ll2==-.'fJ__ __ to _..!..(....,$?=~--3 a "' _\_l_/_:_ __ to _l::...S"...._.9'----
Gross Source Range, cpm: 2a= l02 .. 1f to IO~oS Ja= tDI\3 to (07 o'f Tecbo-ic-=-ian-:::=~f:;/~ __ L_CrJ __ ~_,_ __ ~:==~-=---
All counts times are one minute
Date By Background Counts (1 min. each) Source Counts 71 min. each) ok?
#1 #2 #3 Avg. #I #2 #3 Average YIN
1.\/21 I I'?.. vf£pp, I "2. {, 143 h-7
\\ ']..1/l"l. ~/j,.,;, \2~ I 'fcf l ~(-\ ~ G, it 0'"2..4 ( I 02.40 Hh.2~ IO:l:-3b '-{
II '2-?..-/ n .. v~~ 1"3'8 \ '-f\ l4~
1\ ').7,../12-~J/:-r _{2~ \3£:, \,')...0)
YIN: Y =average background and source cpul llllls within the control limits.
N =average background and source cpm ov.:s not fall within the control limits.
The acceptable ranges were determined from prior background and source check data.
CHARCOAL CANISTER ANALYSIS SYSTEM
SITE LOCATION: w ~ ·,+e tv\ ~S<'\ 1"\ ~ I (I 8 \ ~V\d j VI j J 4 T
CLlENT: E~ ev-"l '1--F"'-' t Is R e ~ o U.~t:.~'S
Culibratjon Check Log
System ID: fV\-0 2/ '!/ -7_0 Calibration Date: ~ /0 C, /1 ""2-Due Date:
Scaler SIN: 51 S 1.9 3 High Voltage: 8'2-5 Window: _..:~.4"-'-c12..___ Thrshld: 2.20
Detector SIN: o__:d-1_5-'3"'---:L _____ Source JD/SN: ~"27-(, (G5 -o.t; Source Activity: s:} .3 Ktci
Blank Canister Bkgd. Range, cpm: 2 cr =_I L._L.f_·_ to J5'l. 3cr= I\] to I 59
Gross Source Range, cpm: 2cr= IOO?~_,.)_o(,V7 Ja=
Technician: V-= ~
q 6 7 :2.. to I OB "2.. h
All counts times are one minute
Dare By Bac~ ound Counts (1 min. each) Source Counts (I min. each) ok?
#1 #2 #3 ,\vg. #I #2 #3 Avera~e YIN
11/21 lt-z. D1 _£,a.. l.Z& I Lf3 l '-t 2. 137 tooq to loo'-fo l D C>'7 I too&q 'I
II/~ II?-ou-, l '2.. G) I t.tLt 1'3 0 13lp ID I 017 1005.,2 10/~;l... JD\ 3q y
llh1-}J£.. ~ 13f6 I 'f I It/~ I 'f I 105"'0)4 t 01'6-1 ID4-S'"3 10411 v
iuh-,.,/t '2. ~~ f..h>J \'1-S \3S l2P> 131 I OLf'\b~ I OS0)0 I D[p2..'-f IOC(DV) v I
·--
I
YIN: Y =average background and source cpm falls witlun the control limits.
N =average background and source cp111 .lth:$ nul JilU within the control limits.
The acceptable ranges were determined from pr: •• r l•.1.:k~ruund aod source check data.
Appendix B
Recount Data Analyses
B
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: I SURFACE: SOIL
AREA: COVER DEPLOYED: 11 19 12 RETRIEVED: 11
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/020 CAL. DUE: 6/09/13
RECOUNT CANISTER ANALYSIS:
AIR TEMP MIN: 31°F
20 12 CHARCOAL BKG:
DATA ENTRY BY: MC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt.Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD PRECISION
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s % RPD
IlO
.fill COUNT
I20
RECOUNT
130
RECOUNT
I40
RECOUNT
ISO
RECOUNT
I60
RECOUNT
I70
RECOUNT
ISO
RECOUNT
!100
RECOUNT
IlO
IlO
I20
I 20
130
130
I40
I40
ISO
ISO
I 60
I60
I70
I70
ISO
ISO
I90
I90
!100
!100
8 16 8 30 11 21 1 2 1 0 4
8 16 8 30 11 22 12 8 55
8 28 8 36 11 21 12 10 13
8 28 8 36 11 22 12 8 55
8 52 8 51 11_21_12 __ 1_0_ 21
8 52 8 51 11 22 12 8 57
8 38 8 44 11 2 1 1 2 10 28
8 38 8 44 11 22 1 2 8 57
9 17 9 4 11 2l-12 -l0~ 36
9 17 9 4 11 22 12 8 58
9 6 8 57 11 21 12 10 46
9 6 8 57 11 22 12 8 58
9 24 9 12 11 21 12 . 10 56
9 24 9 12 11 22 12 8 59
8 57 8 48 11 21 12 11
8 57 8 48 11 22 12 9
6
0
8 14 8 -2-9 11 2i 12 11 16
8 1 4 8 29 11 22 12 9 2
8 8 8 26 11 21 12 11 27
8 8 8 26 11 22 1 2 9 3
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
2
2
2
2
5337 216.3
4509 216.3
12397 211 .6
10679 211 .6
8.7 0.9 0.03
8 .7 0.9 0.04
20 .6
21.1
2.1
2.1
0 .03
0.04
36295 217 :1 ---61---:~---6--:-1 0.03
0.04 30964 217.1 61.9 6 ,2
36981 213.4
32570 213 .4
7340 210.2
6230 210.2
1664 214 .5
1467 214.5
16423 215 .6
14526 215.6
1462 212.8
1350 212 .8
1219 218---:-1
1133 2U.1
1906 217 .1
1 823 217 .1
62.2
64.9
12 . .3
12 .3
2.6
2.7
27.8
29.0
1.0
1.1
6.2
6.5
1.2
1.2
0 .3
0 .3
2.8
2.9
0.1
0.1
o-:-78 o--:-r
~-0.1
1.4
1.5
0 .1
0.2
0.03
0.04
0.03
0.04
0 .03
0.04
0.03
0 .04
0 .03
0 .04
0.03
0.04
0.03
0.04
0.0%
2 .4%
1.1%
4.2%
0 .0%
3.8%
4.2%
9 .5%
6.2%
6 .9%
AVERAGE PERCENT PRECISION FOR THE CELL 2 COVER REGION: 3 .8%
Page 1 of 1
Appendix C
Radon Flux Sample Laboratory Data (including Blanks)
c
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: I SURFACE: SOIL
AREA: COVER DEPLOYED: 11 19 12 RETRIEVED: 11
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/09/13
AIR TEMP MIN: 31•F
20 12 CHARCOAL BKG:
DATA ENTRY BY: MC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
!03
!04
!05
!06
!07
!08
!09
!10
Ill
!12
!13
!14
!15
!16
I17
!18
!19
!20
I21
!22
!23
!24
!25
p6
!27
!28
!29
!30
!31
!32
!33
!34
!01
!02
!03
!04
IOS
!06
!07
!08
!09
IlQ.
Ill
112
!13
8 3 8 24 11 21 12 9 55
8 4 8 25 11_21_]2 9 55
8 6 8 25 11 21 12 9 56
8 7 8 26 11 21 12 9 56
8 9 8 27 11 ii 12 9 59
8 10 8 27 11 21 12 9 58
8 11 8 28 11 21 12 10 3
8 13 8 29 11 21 12 10 3
8 14 8 29 11 21 12 10 4
8 16 8 30 11 21 }t..., 10 4
8 17 8 30 11 21 12 10 6
8 18 8 31 11 21 12 10 6
8 20 a 32 11--n--12 10 7
!14 8 21 8 ----!15 8 22 8
!16 8 24 8
!17 8 25 8
na _a 36 8
!19 8 27 8
!20 8 28 8
I21 . -9 4 8
!22 9 3 8 ---!23 9 2 8
I24 9 0 8
!25 ~ 8-59 8
!26 8 57 8
!27 8 56 8
!28 8 55 8
!29 --8-~53 8
!30 8 52 8
!31 8 51 8
!32 8 4 9 8
!33 8 47 8
!34 8 46 8
32 11 21 12 10
33 11 21 12
34 11 21 12 10
34 11 21 12 10
41 11 21 12 10
35 11 21 12 10
36 11 21 12 10
57 11 211210
56 11 21 12 10
55 11 21 12 10
55 11 21 12 10
54 11 21 12 10
53 11 21 12 10
53 11 21 12 10
52 11 21 12 10
s1 1:i"2'l":l2 io
51 11 ~ 21 1L2 1 0
so 11 21 12 10
so 11 21 12 10
49 11 21 12 10
48 11 21 12 10 ·---
7
9
10
11
13
13
14
14
16
16
17
17
19
19
21
21
22
22
24
24
1
!
1
1
2
1
1
1
1
1
1
1
1
1
1921
!_?684
1302
20166
l 731
1831
20931
2331
25546
5337
19805
8890
1.2516
7168
1 22628
1 21041
2_ 1778
1 17157
1 12397
1 -1001
~---~4881
1 1280
1 13781
1 20068
1 19712 ----1 3599
1 32130
1 ~ 20078
1 36295
1 6438
1 45278
1 7820
1 23551
Page 1 of 3
214.7
217.8
214.0
213.7
213.0
216 .6
208.8
215.4
214.6
216.3
216.1
212.6
214.5
211.4
213.6
214 .1
214.0
213.7
211.6
217.2
213.8
215.8
213.4
213.0
213.7
217.2
212.0
216.0
217.1
213.2
215.0
215 .1
215.5
3.0
25.9
2.0
33.5
1.2
2.8
35 .2
3 .7
43':1
_8.}
33.4
14.7
21 :0
11.8
0.3
2.6
0.2
3.3
0 .1
0.3
3 .5
0.4
4.3
0 .9
3.3
1.5
2 .1
1.2
37 .8 3.8
35.6 -3 .6
1.2 0.1
29.0 2.9
20.6 2.1
1.5 -0 .1
25.6 _2 .5
1.9 0.2
23.1 2.3
34.1 3.4
33 .1 3 .3 ---5.9 0.6
54 .2 5. 4
34.1 --3 .4
€J .2 6.1
10.8 1.1
76 .3 7.6
1u --1.3
39.6 4.0
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0.03
0 .03
0.03
0.03
0.03
0.03
0.03
Spilled
0.03 __ ~---
0.03
0.03
0.03
0. 03::.-..-~---~
0.03
0.03
0.03
0 .03
0.03
0.03
0.03
0.03
0.03
0 .03
0.03
0 .03
~~~~--~
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: I SURFACE: SOIL
AREA:COVER DEPLOYED: 11 19 12 RETRIEVED: 11
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/09/13
AIR TEMP MIN: 31°F
20 12 CHARCOAL BKG:
DATA ENTRY BY: MC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm WI. Out:
TARE WEIGHT:
180.0
29.2
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
!35
!36
I39
I40
I41
I42
I43
I44
I45
,I46
I47
I48
I49
I 51
I 52
I 53
!54
ISS
I 56
I 57
ISS
I 59
I60
I61
I62
I63
I64
I65
I66
I67
I68
!35
!36
I37
I38
I39
I40
141
l_4t_
I43
I44
I45
I46
I47
I48
I 49
ISO
-~-I 51
I 52
I 53
I 54
ISS
I 56
157
ISS
I 59
I60
I61
!_62
I63
I64
I65
!§6
I67
I68
8 45
8 44
8 42
8 41
8 39
8 38
9 26
9 25
9 24
8 48 11 21 12 10
8 47 11 21 12 10
8 46 11 21 12 10
8 46 11 2l~l2 10
8 45 11 21 12 10
8 44 11 21 12 10
9 10 11 21 12 10
9 9 11 21 12 10 ---9 8 11 21 12 10
9 23 9
9 22 9
9 2L 9
9 20 9
9 19 9
9 18 -9
9 17 9
9 16 9
9 15 9
9 14 9
9_13_ 9
9 12 9
9 11 9
9 10 8
9 9 8
9 7 8
9 6 8
9 27 9
9 28 9
8 11 21 12 10
7 11 21 12 10
6 11 1}_12 10
6 11 21 12 10
5 11 21 12
5 11 ii -12 10
4 11 21 12 10
3 11 21 12 10
3 11 21 12 10
2 11 ~2 l 12 10
1 11 ,11_ 12 10
1 11 21 12 10
0 11 21 12 10
59 11 21 12 10
59 11 21 12 10 ---58 11 21 12 10
57 11 21 12 10
10 11 2l 12 10
11 11 21 12 10
25
25
27
27
28
28
30
30
31
31
33
u 34
36
36
37
37
39'
3 ~
40
40
42
43
47
46
50
50
1
1
1
t
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
1
2
2
1
1
1
9 2~ 12 11 n 12 10 s1-·-1
9 30 9 12 11 21 12 10 51 1
9 31--9 13 11 21"12 10 5~3--1
9 32 _J 14 11 2.l.....J-2 10 53 -1
9 32 9 14 11 21 12 10 54 1
9 30 9 13 11 21 12 10 54 1
Page 2 of 3
2546 215.8
31117 214.3
20009 -211. 7
22982 .217 . 4
22891 211.7
36981 213.4
40096 -212 .2
8823 216.2
8394 212.5
48478 217 .5
64747 213.2
3274 216.6
13037 212.9
13437
7340
32849
11086
86623
2616.1,
3321
125022
86635
1792
1727
1664
4918
3779
213 .1
210.2
215.2
213.4
214.0
214.2
212.4
212.6
213.4
213.9
214.7
214.5
212.6
215 .0
2616 212.4
45122 211.6
16436 ~12.6
1 7784_ 213. 7
2891 214.5
4525 213.7
4.1
52.3
33.9
38.~
38.8
62 .2
68 .9
14 .8
14 .2
82.5
11LS
5.3
22.2
22 .9
12 .3
56.4
18.7
149.2
44.;.!
5 .5
213.0
149.2
1.3
1.2
2.6
8~
6 .2
4.3
77 .0
2'8:2
30.2
4.8
7.5
0.4
5.2
3.4
3.9
3.9
6.2
6.9
1.5
1.4
8.2
11.1
0.5
2.2
2.3
1.2
5.6
1.9
14.9
4.4
0.5
21.3
14.9
0.1
0 .1
0.3
0.8
0.6
0.4
7.7
2.8
3.0
0 .5
0 .7
0.03
0.03
o-:"03
0~3
0.03
0.03
o-:-o3
0.03
0 .03
0 .03
o:o3
0 .03
0 .03
0.03
0 .03
0 .03
0 .03
0.03
0 .03
0 .03
0.03
o-:D 3
Q.;.Q..3
0.03
0.03
o-:-o3
2...:_0}
0 .03
0 .03
0.03
0 .03
0 .03
0 .03
Spilled
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: I SURFACE: SOIL
AREA:COVER DEPLOYED: 11 19 12 RETRIEVED: 11
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21 , M02/D20 CAL. DUE: 6/09/13
AIR TEMP MIN: 31°F
20 12 CHARCOAL BKG:
DATA ENTRY BY: MC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt.Out:
TARE WEIGHT:
180.0
29.2
g.
g.
GRID SAMPLE DEPLOY RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
LOCATION I. D. HR MIN HR MIN MO DA YR HR MIN (MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
I69
I70
I71
I72
I73
I74
I75
I76
I77
I78
I79
ISO
I81
I82
I83
I84
I87
I88
I89
I90
I91
I92
I93
I94
I95
I96
I97
I98
I99
IlOO
I69 9 27
I70 9 24
I71 9 22
I72 9 19
I73 9 16
I74 9 1 3 ----I75 9 11
I76 9 8
I77 9 5
I78 -9 3
I79 9 0
ISO 8 57
I81 --8 54
I82 8 52 ---I83 8 49
I84 8 46
ISS 8 43
I86 8 41
I87 8 38
I88 8 35
ra9 a 11
I90 8 14
I91 8 16
I 92 8 19
9 13 11 21 12 10
9 12 11 21 12 10
9 11 11 21 12 10
9 10 11 21 12 10
9 9 11 21 12 10
9 9 1J__ll_12 10
9 8 11 21 12 11
9 7 11 21 12 11
8 45 11 2l 12 11
8 46 11 21 12 11
8 4 7 11 21 12 11
8 48 11 21 12 11
8 49 11 21 12 11
8 so 11 _21_12 11
8 52 11 21 12 11
8 54 11 21 12 11
8 56 11 21 12 11
8 57 11 21 12 11
8 59 11 21 12 11
9 0 11 21 12 11
8 28 11 21 12 11
8 29 11 21 12 11
8 30 11 21 12 11
8 32 11 21 12 11
56
56
57
57
59
59
0
0
2
3
5
6
9
9
10
10
12
12
13
13
15
16
19
19
I93 -
I94
8
8
8
8
8
8
8
8
22 8 33 11 21 12 11 22
2 5 8 34 11 21 12 11 22
I95
I96
I97
I98
I99
IlOO
27 8 36 11 21 12 11 23
30 8 3 7 11 21 12 11 23
33 8 38 11 :21-12-11 25
3 8 24 11 21 12 11 25
6 8 25 11 21 12 11 26
8 8 26 11 21 12 11 27
1 8036
1 16423
1 19671
1 8845
1 13675
1 1531
1 1376
1 5333
1 3 4662
2 1363
1 4326
2 1462
1 5464
1 17101
1 17872
1 1974
1 --4035
1 5044
1 2715
1 5165
1 --4217
2 1219
2 1477
1 2254
219.9
215.6
218.7
215.5
215.6
218.2
215.7
218.3
213.6
214.9
216.3
212.8
215.7
215.9
213.8
215.9
216.0
213.1
213.1
216.5
216 .6
218.1
216.9
218 .4
1 ~ 6130 218.7
1 l]17 214.2
1 2428 217 .7
1 4077 214.0
1 21390 214.6
1 7843 217 .0
1 5755 215 .1
2 1906 217.1
AVERAGE RADON FLUX RATE FOR THE CELL 2 COVER REGION:
Page 3 of 3
13 .6 1.4
27~ -2.8
33 .7 3.4
14 .8 1 . 5
23.3 2.3
2 ._4. -0.2
2 .1 0.2
8.8 0.9
60.1 -6.0
0 .9 0.1
7.2 0.7
1.0 0.1 9:2 -0.9
28.9 2.9
30 .4 3.0
3 .1 0 .3
6 .6 0.7
8.2 0.8
4. 4 0. 4
8. 4 0. 8
7 ~0 ~ 0. 7
0.8 0.1 ---1.0 0 .1
3. 6 0.4
10.3 1. 0
2.7 0.3
3 .9 0 .4
6.7 0.7
36.6 3 .7
13.0 1. 3 -----9 .6 1.0
1.4 0.1
26 .1 pCi/m2s
0.03
0.02
0.03
0.03
0.03
0.03
0.03
0 .03
0.03
0.03
0.03
0.03
0 .03
0 .03
0 .03
0.03
0.03
0.03
0.0-3--------~----
0.03
0 .03
0.03
0.03
0 .03
0.03
0.03 __ ~--------~
0.03
0.03
0.03
0 .03
0.03
0.03
CLIENT: DENISON MINES PROJECT: RADON FLUX MEASUREMENTS, WHITE MESA MILL
PILE: 2 BATCH: I SURFACE: SOIL
AREA: COVER DEPLOYED: 11 19 12 RETRIEVED: 11
COUNTED BY: DLC FIELD TECHNICIANS: CS,MC,DLC
COUNTING SYSTEM I.D.: M01/D21, M02/D20 CAL. DUE: 6/09/13
BLANK CANISTER ANALYSIS:
AIR TEMP MIN: 31°F
20 12 CHARCOAL BKG:
DATA ENTRY BY: MC
PROJECT NO.: 12004.00
WEATHER: NO RAIN
148 cpm Wt. Out:
TARE WEIGHT:
180.0
29.2
GRID SA!>IPLE RETRIV ANALYSIS MID-TIME CNT GROSS GROSS RADON ± LLD
g.
g.
LOCATION I. D. HR I>IIN HR MIN MO DA YR HR !>UN {MIN) COUNTS WT IN pCi/m2 s pCi/m2 s pCi/m2 s COMMENTS:
I BLANK 1 I BLANK 1 8 0 8 25 11 21 12 9 5 10 1680 202.0 0.03 0.02 0.03 CONTROL
L&~K 2 I BLANK 2 8 0 8 25 11 2_1 _2.2 9 5 10 1596~ 208.6 0.0_?~ 0.02 0.03 CONTROL .
I BLANK 3 I BLANK 3 8 0 8 25 11 21 12 9 18 10 1666 209.3 0.03 0 .02 0 .03 CONTROL
I BLANK 4 I BLANK 4 8 0 8 25 11 21 12 9 18 10 1638 210.5 0 .03 0.02 0.03 CONTROL
'I-BLANK 5 I BLANK 5 8 0 8 25 112 i-r2 9 30 10 1fo5 207.7 0.04 -0.02 0.03 CONTROL
AVERAGE BLANK CANISTER ANALYSIS FOR THE CELL 2 COVER REGION: 0 .03 pCi/m2s
Page 1 of 1
Appendix D
Sample Locations Map (Figure 2)
D
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m ... "' ~ ~ QJ ... ... ... 0 1 w 0 0 0 0 0 0 0 0 0 -o:M.;(<)-.,. .., .. ... ... 'II' "' .., ISO ... 0 0 0 0 0 0
-<8..ll-
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-oOUSI+-.. "' '"' .. , ~· 0 0 0 0 0
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8J "' "' ... ... 0 0 0 0 0 ~ II
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I DLANQIN!:Z, !.!IAI:I
NESHAPS .201.2
I NOVBMBER2012SAMPUNG
PREPARED FOR I ENERGY FUELS RESOURCES
I ~
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£IMRONMENTAl. U.C
THIS OAAWING IS THE PAOP~RTY Of 1tU.CO ~U.C.AJ«>ISNOJl'OB(­~O,N.::>OIAEOORVSEOFOitANY OTKVI:PfiOJKTO«~OITWISI'tiOJKl OIC£PT l'f' M:/liHN£HJwrTH TEUCo.
Letter to B. Bird
March 29, 2013
Page 15 of 15
ATTACHMENT 2
SENES Consultants Limited Technical Memorandum
WIDTE MESA MILL CELL 2 RADON FLUX
Prepared for:
Energy Fuels Resources (USA) Inc.
225 Union Blvd., Suite 600,
Lakewood, CO, US, 80228
Prepared by:
SENES Consultants Limited
121 Granton Drive, Unit 12
Richmond Hill, Ontario
L4B 3N4
March 2013
Printed on Recycled Paper Containing Post-Consumer Fibre
~
White Mesa Mill Cell 2 Radon Flux
EXECUTIVE SUMMARY
Energy Fuels Resources (USA) Inc. (EFRI) is currently preparing one of their uranium tai ling
cells (Cell 2) at their White Mesa Uranium Mill, located in San Juan County Utah, for final
reclamation. One of the regulatory requirements for site licensing is meeting the long-term
radon emanation standard for uranium mill tailings, and therefore, EFRl must install an
engineered cover designed to limit the flux of radon to the atmosphere to the applicable limit of
20 pCi m-2 s-1. During operations, prior to installation of the final engineered cover, the tailings
cell must also maintain radon emissions from the cell within this 20 pCi m·2 s·1 standard.
In order to place the final cover, the tailings need to be first dewatered and stabilized. Since the
ability of radon to diffuse through air is several orders of magnitude larger than through water,
the radon flux from the surface of tailings in the process of reclamation is expected to increase as
the tailings are progressively dewatered.
The present report looks at the potential effects of dewatering on the radon flux from Cell 2. The
radon model used in this report was based on the detailed methodology recommended by the
U.S. NRC Regulatory Guide 3.46 (1989), which uses a one-dimensional steady-state gas
diffusion model. The parameter values were based on values used in MWH (201 1) updated by
insight gained from recent measurements of thicknesses of cover, depth to water table in the
tailings and radon fluxes in Cell 2.
The analyses provided in this report confirm that, as expected on the basis of diffusion
principles, the radon t1ux from the sw·face of the Cell 2 tai lings is expected to increase as
dewatering progresses.
The dewatering operation is expected to take several years to complete, and, if addition of
temporary cover of random fill is not technically or financially feasible, exceeding the radon flux
standard will be an unavoidable but temporary consequence of the dewatering actions required to
reclaim Cell 2. Thjs elevated radon flux will persist through reclamation but would be reduced
to below the regulatory limit once the final cover is in place.
Tn order to explore potential interim actions that could be taken to maintain radon flux within the
20 pCi m·t s·' standard, we have also evaluated the extent to whi ch radon emanations from the
cell can be reduced by increasing the thickness of the cunent interim cover on Cell 2. Based on
our analysis, we have concluded that (a) the addition of approximately 0.5 feet of random ftll
cover (at between 80 and 95% compaction) to the current interim cover would be expected to
reduce the average radon flux from its current rate of approximately 26 pCi nf2 s-1 to less than 20
pCi m·2 s·', (b) the addition of approximately 1.0 feet of random fill cover (at 80 to 95%
compaction) to the current interim cover would be expected to reduce the average flux of
350496-011 -March 2013 ES-1 SBNES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
approx imately 26 pCi m-2 s·', plus the increased radon resulting from further dewatering over
approximately the next year, to less than 20 pCi m-2 s·1, and (c) the addition of approximately 2.0
feet of random fill cover (at 80 to 95% compaction) to the current interim cover would
reasonably be expected to be sufficient to reduce surface radon .tlux to below 20 pCi m-2 s·',
regardless of the depth of dewatered tails.
350496-0 11 -March 2013 ES-2 SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
TABLE OF CONTENTS
Page No.
EXECUTIVE SUMMARY ....................................................................................................... ES-1
1.0 INTRODUCTION ........................................................................................................... 1-1
2.0 BACKGROUND TO TRANSPORT OF RADON THROUGH SOIL. .......................... 2-1
2.1 Radon Production ................................................................................................ 2-1
2.2 Transport through Cover ...................................................................................... 2-1
2.3 Dewatering and Radon Flux ................................................................................ 2-3
3.0 TAILINGS AND COVER CHARACTERISTICS ......................................................... 3-1
3.1 Tailings ................................................................................................................ 3-1
3.2 Cover. ................................................................................................................... 3-2
3.3 Measurements of Thicknesses and Radon Flux ................................................... 3-3
4.0 METHODOLOGY .......................................................................................................... 4-1
4.1 Calculation Methodology .................................................................................... 4-1
4.2 Analysis of Test Pit Data ..................................................................................... 4-1
4.3 Radium-226 Activity in Tailings ......................................................................... 4-5
5.0 RESULTS AND CONCLUSIONS ................................................................................. 5-1
5.1 Tailings Dewatering and Radon Flux ............................................................. .' .... 5-1
5.2 Required Cover Thickness ................................................................................... 5-2
6.0 REFERENCES ................................................................................................................ 6-1
350496-0 II -March 2013 SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
LIST OF TABLES
Page No.
Table 2-1 Radon Attenuation of Various Covers (U.S. EPA 1986) ......................................... 2-2
Table 3-1 Tailings Characteristics ............................................................................................ 3-2
Table 3-2 Characteristics ofRandom Fill. ................................................................................ 3-2
Table 3-3 Average Radon Flux Measured on Cell 2 ................................................................ 3-3
Table 3-4 Tailings and Cover Thickness and Radon Flux Measured in Locations
Sampled in 2011 and 2012 ....................................................................................... 3-4
Table 3-5 Standpipe Water Level and Radon Flux ................................................................... 3-5
Table 4-1 Parameter Values and Equations .............................................................................. 4-3
Table 4-2 Radon Attenuation of Various Covers ..................................................................... 4-4
Table 5-1 Estimated Required Thickness of Cover .................................................................. 5-3
LIST OF FIGURES
Page No.
Figure 2-l Experimental Diffusion Coefficients (UNSCEAR 2000) ........................................ 2-1
Figure 2-2 Radon Penetration of Various Covers (U.S. EPA 1982) .......................................... 2-2
Figure 2-3 Effects of Depth to Water Table on Radon Flux ...................................................... 2-3
Figure 3-1 20 II and 2012 Sampling Locations and 2013 Thicknesses ..................................... 3-4
Figure 4~ 1 Estimated Radon Flux Based on the Recommended Average Diffusion
Coefficient (0.01 cm2/s) Compared to Measured Fluxes .......................................... 4-4
Figure 4-2 Sensitivity of Estimated Radon Flux to Radium-226 Activity in Tailings .............. 4-5
Fi.gure 5-1 Estimated Average Radon Flux from Bare and Covered Tailings ........................... 5-l
Figure 5-2 Estimated Flux versus Cover Depth for the Current Dry Tailings* ......................... 5-2
350496·0 II -March 2013 11 SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
1.0 INTRODUCTION
SENES Consultants Limited (SENES) was retained by Energy Fuels Resources (USA) Inc.
(EFRI) to conduct an assessment of radon flux arising fi·om the reclamation of one of their tailing
cells (Cell 2) at the White Mesa Uranium Mill in San Juan County Utah (the "Mill").
Between 1980 and 2000, about 3,911,000 tons of ore with an average ore grade of about 0.350%
U30s were processed in the mill, as a result of which some 2,337,000 tons of tailings were placed
in Cell 2 at the Mill. Soil stockpiled at the site (loam to sandy clay -referred to hereafter as
"random fill") was used to cover the tailings until 2007, when Cell 2 was completely covered by
about 4.5 ft. of random fill. As part of developing the final reclamation actions required to
achieve the radon flux standard of 20 pCi m-2 s-1, a final engineered cover was designed by
TIT AN Environmental (1996), and an updated design has recently been proposed by MWH
Americas Inc. (20 11 ), whjch is currently under review by the Utah Department of Environmental
Quality, Division ofRadiation Control ("DRC").
To place the fmal cover, the tailings first need to be dewatered and stabilized. This process is
required under Part I.D.3(b) of the Mill's State of Utah Groundwater Discharge Permit, and is
also part of the reclamation actions which are currently underway and will require a number of
years to complete. Since the ability of radon to diffuse through water is several orders of
magnitude lower than through air, the radon flux from the surface of tailings in the process of
reclamation should be expected to increase as the tailings are progressively dewatered.
Release of radon from uranium tailings is regulated by the U.S. EPA's Code of Federal
Regulations at 40 CFR Part 61.250, for operating mill tailings and at 40 CFR Part 194 (EPA
1986) for reclaimed mill tailings. For operating mill tailings, 40 CFR 61.252 provides that
'Radon-222 emissions to the ambient air fi'om an existing uranium mill tailings pile shall not
exceed 20 pCilm2/sec of radon-222.' For reclaimed tailings, 40 CFR Part 194 requires that ' ...
uranium tailings cover be designed to produce reasonable assurance that the radon-222 release
rate would not exceed 20 pCi/m2/sec for a period of 1,000 years to the extent reasonably
achievable and in any case for at least 200 years when averaged over the disposal area over at
least a one year period'. This standard has also been adopted by the State of Utah, which
licenses the Mi ll , as the long-term emanation standard for uranium mill tailings (Utah
Administrative Code Rule 313-24).
For the short term drying conditions (during which a portion of the tailings will lose saturation
and the formerly water-filled tailings pore space will become air-filled) an increase in radon flux
should be expected, which could lead to a radon flux in excess of the 20 pCi m-2 s-L standard set
out in 40 CFR 61.252. There are provisions for new tailings facilities (i.e. those constructed after
December 15, 1989) whjch are subject to phased disposal (U.S. EPA 1998), and which are not
350496-011 -March 2013 1-1 SENES Consultants Limited
While Mesa Mill Cell 2 Radon Flux
subject to the 20 pCi m·2 s·1 standard set out in 40 CFR 61 .252 during operations. The increase
in radon flux due to dewatering does not pose a problem for such cells. However, the regulations
do not address how existing tailings facilities are expected to manage increases in radon :flux
during the dewatering process prior to installation of the final reclamation cover.
The present report assesses the potential effects of dewatering on the radon flux from Cell 2
during the dewatering process. This report also describes the data and methods used in the
assessment. In addition, we provide illustrative calculations of the th ickness of a temporary
cover needed to achieve the radon flux standard of 20 pCi m·2 s·1, during the dewatering process
prior to installation of th e final reclamation cover.
350496-0\l -March 20 13 1-2 SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
2.0 BACKGROUND TO TRANSPORT OF RADON THROUGH SOIL
2.1 RADON PRODUCTION
Radon is produced through the radioactive decay of radiurn-226, and has a half-life of 3.82 days.
Radium-226 is a long-lived decay product of the uranium-238 seri es present in the tailings
created through the milling of uranium ore. Radon-222 is the only member of the decay chain
which is in a gaseous form. As a (noble) gas, radon-222 can be released to the atmosphere if it
emanates from a mineral matrix that contains radium-226. The radon production rate (q) in a
porous radium-bearing material can be expressed as:
E /3 q = [Ra] X p X p X A,= p
where, [RaJ is radium-226 concentration, p is bulk density, E is emanation coefficient, P is
porosity and A. is radon decay constant. p is defined as the emanation power.
2.2 T RANSPORT T HROUGH COVER
When tailings are covered by an inert material, the diffusive radon flux (J) at the surface of the
cover can be expressed approximately as:
-z 1 = f oeT
where, Jo is the radon flux from the uncovered tailings, Z is the cover thickness and L is the
diffusion length (or the distance to which concentration decreases by a factor of e), defined as
follows:
L= jf;
where, 0 is the bulk diffusion coefficient, and DIP is the effective diffusion coefficient.
Experimental effective diffusion coefficients provided by UNSCEAR (2000) are shown in
Figure 2-1. The effect of increased water content in pore spaces in reducing diffusion is evident.
10·
FIGURE 2-1 EXPERI MENTAL D IFFUSION M
1
C OEFFICIENTS (UNSCEAR 2000) ~ 10·6
u ~ J0·7 0 u
z 2 i JO·I
0
UJ ~ 10·9
UJ IO·I
350496·01 1-March 2013 2-1
0
• ~ilporosiry0.2
0 Soil porojiry 0.2S
• Sol/porojity0.4
0.2 0.4 0.6 0.8
VOLUME FRACTION OF WATER SATURATION
SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
The U.S. EPA ( 1982, 1986) also provides a (simplified) method for modeling of radon
transmission through soil/earth covers. This method uses sjmilar concepts of radon attenuation
as outlined above; however, some of the terminology varies slightly. In particular, the EPA
refers to a half-value layer (HVL)~ which is defined as the thickness of material that reduces
radon emissions to one-half of its initial value (as distinct from 1/e). The llVLs depend on cover
composition and moisture content among other factors that affect the ability of radon to diffuse
through the cover. To a reasonable approximation, radon transmission (T) through soil/earth
covers of thickness (t) may be approximated as follows:
T = e-t/L
where, L is the cover thickness through which radon is attenuated by a factor of 1/e. The HVL is
given by ln(2) *L = 0.693*L. Repeated application of this formula can be used to approximate
the effect of multiple covers. HVLs for various covers, and corresponding radon attenuation
coefficients and radon transmission factors developed by the EPA are shown in Table 2-1 and
illustrated in fjgure 2-2.
TABLE2-l RADON ATTENUATION OF VARIOUS COVERS (U.S. EPA 1986)
Cover Moisture (0A,) HVL Attenuation cocf'ticient (tim)
(meters (m))
Sandy soil 3.4 1 0.7
Soil 7.5 0.75 0.9
Soil 12.6 0.5 1.4
Compacted moist soil 17 0.3 2.3
Clay 21.5 0.12 5.8
FIGURE 2-2 RADON PENETRATION OF VARIOUS COVERS (U.S. EPA 1982)
j -,---------------------------------------------------~
OS
oL-----~~~~--~~~==~----_j
0 1,5
Cover Thickness (meters)
350496-011-March 2013 2-2 SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
2.3 DEWATERING AND RADON FLUX
The relationship between the thickness of dry tailings and radon flux can be explained based on
Figure 2-3. As the water in pores is replaced with air, more radon becomes available for
exchange with air as radon is better able to diffuse through the tailings to the air/tailings surface.
When the pore space in the porous material is filled with water, the diffusion coefficient is about
1/100111 of that in pores filled with air (e.g., Tanner 1964). Therefore, it is expected that as the
tailings dewatering progresses, radon flux to air wm also increase. However, as seen later in
Section 5.2, due to the short half-life of radon (3 .82 days), a tailings thickness greater than about
3-5 m is effectively equivalent to an infinitely thick radon source, because the radon generated
below such thicknesses will decay before it can diffuse through to the surface of the tailings.
FIGURE 2-3 EFFECTS OF DEPTH TO WATER TABLE ON RADON FLUX
Air n t l
Containing Solids
350496-011 -March 2013 2-3
Air
•••·• •'•• •'1 e • .... ~ ........ . ... ........ . •• • • • 't ..• "
E• .• .• • .,.,.•.,.•.• .... N ~ .. 6 ..... 6 • ..,
A Ra-226
Containing Solids
SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
3.0 TAILINGS AND COVER CHARACTERISTICS
T he following Section, which describes Cell 2 and the characteristics of available cover
materials, is based on information in MWH (2011) as well as recent information collected by
Tellco (2012).
3.1 TAILINGS
The M ill tailings are reported as generally silty sand but heterogeneous due to the placement
process. Based on grain-size analyses performed on the tailings, sand-sized particles arc
dominant with the remainder being silt-and clay-sized particles. The average grain size
distribution for the Mill's tailings, based on 13 samples. consists of 57% sand, 26% silt, and 7%
clay.
The activity of radium-226 in the tailings is reported by MWH at 981 pCilg. This value was
used in this report as the average activity for all the calculations. However, there is some
uncertainty about the radium-226 activity present in the tailings1• The effect of this uncertainty
was analyzed assuming a 25% range in Ra-226 activity.
The tailings cells at the Mill were lined with a synthetic geomembrane liner which has led to the
long-term accumulation of water from infil tration of precipitation and saturation of the tailings.
During and for a period after placement, the tailings were submerged under impounded water.
The submerged tailings were primarily comprised of smaller particle size material (slimes). The
perimeter of the tailings cells comprised a mixture of particles (slimes and sand) which deposited
on the perimeter beaches. The area was not covered with water but was wetted and kept
satlU'ated. During the pre-closure period, the beaches became unsaturated and a random fi II
cover was placed on the tailings. By 2008, the entire surface of Cell 2 had been covered with a
random fill soil cover. Table 3-1 provides some key characteristics of the tailings as provided in
MWH (2011).
1 The average grade of ore processed at the Mill since its inception is estimated to be approximately 0.350% U30 8.
Assuming secular equilibrium in the ore between uranium-238 and radium-226, and that all radium in the original
ore goes into the tailings, the activity of radium-226 will be calculated as (0.00350 g U30 s/ g ore) x (0.848 g
U-238/ g U30 8) x (33,000 pCi U-238/ g U-238) -= 981 pCi U-238/g ore. Although EFRI estimates the average
grade of ore processed at the Mill to be approximately 0.350% U30 8, the average grade of ore that generated the
tailings deposited into the cells may have varied as between Cell 2 and Cell 3. As a result, although 981 pCi/g
radium-226 is EFRI's best estimate, thero is some uncertainty as to the average grade of radium-226 in Cell 2.
3504\16-01 1-March 2013 3-1 SENES Consultants Lirnilcd
White Mesa Mill Cell 2 Radon Flux
TABLE3-1 TAILINGS CHARACTERISTICS
Parameter Value
Thickness 30ft. (914 em)
Radium activity concentration 981 pCi/g
Radon emanation coefficient 0.19 (based on laboratory data)
Specific gravity 2.75 (based on laboratory tests)
Placed density 74.3 pcf (based on laboratory tests)
Porosity 0.57 (calculated)
Long-te1m moisture content 6% (conservative assumption based on NRC)
3.2 COVER
In 1996, TITAN designed a 'final' cover for protection of the tailings in the long-term. The
TITAN cover comprised 3 ft. of random fill, one foot of clay, another 2 ft. of random fill and a
rock cover (from bottom to top). By 2008, Cell 2 had been completely covered by a layer of
random fill of varying depths. MWH (2011) has proposed an updated cover design which
recommends three layers of random fill including 2.5 ft. un-compacted (minimally compacted to
about 80% standard Proctor compaction), 2.5 ft. compacted (to 95%), and 3.5 ft. compacted (to
80%), and 0.5 ft. of a gravel-admixture for erosion protection. MWH's proposed updated cover
design is currently under review by DRC.
The existing interim cover (and the one studied for the drying period) consists of the random fill
stockpiled at the site. Table 3-2 provides characteristics of the random fill as provided in MWH
(2011).
TABLE 3-2 C HARACTERISTICS OF RANDOM FILL
Parameter Value
Radiwn activity concentration 0 (assumed based on guidance in NRC 1989)
Radon emanation coefficient 0.19 (based on laboratory data)
Specific gravity 2.67
Placed density 93.4 pcf(low compaction) and 110.9 pcf(highcompaction)
Porosity 0.44 (low compaction) and 0.33 (high compaction)
Long-term moisture content 7.8% (laboratory results and NRC estimation method)
350496-011 -March 2013· 3-2 SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
3.3 MEASUREMENTS OF THICKNESSES AND RADON FLUX
Past measurements of Cell 2 indicate that the average radon flux over the entire cell (including
sections submerged in water, saturated beaches and under-cover areas) never exceeded the
20 pCi m-2 s-1 standard before 2012. The proposed updated final cover is also predicted to
comply with the regulations (MWH 2011 ); however, recent measurements have shown an
increase in radon flux as dewatering has progressed. The average of the most recent radon
measurements on Cell 2 in 2012 exceeds the 20 pCi m-2 s-1 standard. Table 3-3 shows average
radon flux measured on Cell 2 since 1992.
During 2013, cover depth and the 'thickness of exposed sand' (i.e. dry tailings) and 'feet of
solution' (i.e. wet tailings) were measured in test pits at 10 of these same locations on Cell 2.
Figure 3-1 provides a map of Cell 2 showing the locations of the 10 sampling locations and test
pits. Table 3-4 shows the overall average of measured levels of radon flux at each of these 10
sampling locations. Both Figure 3-1 and Table 3-4 provide the thicknesses of wet and dry
tailings, the thickness ofthe existing cover material and radon fluxes at each test pit location.
TABLE 3-3 AVERAGE RADON FLUX MEASURED ON CELL 2
Year Beach Under cover Both
1992 12.9 7 9
1993 27.5 9.7 12.3
1994 23.3 7.7 10
1995 28.4 6.1 9.5
1996 36.2 14.2 17.3
1997 41.3 7.4 12.1
1998 41.9 9.8 14.3
1999 25.7 12.4 13.3
2000 23.5 7.9 9.3
2001 32.2 18.2 19.4
2002 62.8 15.1 19.3
2003 71.5 13.3 14.9
2004 73.7 12.6 13.9
2005 55 .8 6.6 7.1
2006 65.7 7.9 8.5
2007 50.2 13.1 13.5
2008* -3.9 3.9
2009 -13.7 13.7
2010 -12.8 12.8
201] -18 18
2012** -25.9 25.9 .. ·l -1 un1t. pC1 m s . * First year with no beaches exposed (all under interim cover). * * Represents the average of four measurement events taken in 20 12.
350496-011-March 2013 3-3 SENES Consultanls Limited
White Mesa Mill Cell 2 Radon Flux
F IGURE 3-1 2011 AND 2012 SAMPLING LOCATIONS AND 2013 THICKNESSES
10 Feet
CJ cover
D DryTailing
-WetTailing
Source: Google Earth; Cell 2 boundaries and sample locations based on Figure 2 in Tel leo (2012).
TABLE 3-4 TAILINGS AND COVER THICKNESS AND RADON FLUX MEASURED IN LOCATIONS
SAMPLED IN 2011 AND 2012
Sampling Thickness, ft. Radon Flux, oCi m-2 s-1
and Test Dry September October Pit Cover Wet Tailings
Location Tailings 2011 2012
D22 3.23 11.40 4.23 18.9 36.4
D25 1.17 14.71 4.16 23.8 40.8
D28 3.77 10.92 10.21 63.7 63.5
030 5.67 10.13 11.92 48.2 57.5
048 8.88 11.13 10.00 2.5 2.7
085 5.77 12.98 13.82 6.8 6.8
037 2.42 17.96 5.63 34.4 43.8
044 4.96 13.21 11.41 89.6 90.3
D42 4.38 8.00 18.41 16.9 16.2
077 3.29 6.96 20.05 69.9 67.7
350496·01 l -March 2013 3-4 SENES Consultants Limited
White Mesa Mill Cell 2 Radon FLux
Table 3-5 shows the change in average observed water levels in the slimes drain standpipe in
Cell 2 and the average observed radon flux from the entire surface of Cell 2 since 2008. The
third column of Table 3-5 shows the year-to-year difference in observed water level in the Cell 2
slimes drain standpipe. Column 4 shows the average Cell 2 radon flux ti·om the entire surface of
Cell2 for each year, and column 5 shows the year-to-year change in average radon flux. (Values
in brackets reflect year-to-year lowering in water levels or radon flux.)
One important observati on is immediately apparent, namely that a lowering of the water level in
Cell 2 results in an increase in the average radon flux and an increase in water level results in a
decrease in the average radon flux. Th:is observation from field data supports the previously
noted observation based on theory.
TABLE3-5 STANDPIPE WATER LEVEL AND RADON FLUX
A Water Level !':!.Flux From
From Year to Year to Year !l Flux
Water L evel Year (ft) Flux per (~Ci m-2 s·1) !':!.Water Level Year (fmsl) Year Values in Values in brackets (pCi m-2 s"1) brackets reflect Values in brackets
reflect decrease in reflect decreases
water level decease in radon
flu x
2008 5600.56 3.9 9.8 (0.397) 9.8 (0.397) =24.7
2009 5600.163 13.7 (0.9) 0.256 (0.9) =3.2 0.256 2010 5600.419 12.8 5.2 (1.005) 5.2 (1.005) =5.2
2011 5599.414 18 7.9 (2.104) 7.9 (2~4) =3.7
2012 5597.3 1 25.9
Column 6 is the ratios of the year-to-year change in average radon flux levels divided by the
corresponding year-to-year change in water levels, which, in effect, is a global derivative
reflecting the slope of the underlying curve. Roughly speaking, based on those observations, the
average radon flux increases by about 4 pCi m-2 s-1 (with a range of about 3 to 5 pCi m·2 s"1).
Although based on limited data, it is noteworthy that since 2008 the change in radon flux: has
been consistently inversely related to changes in water levels, and the changes have been
re latively consistent over the last three years.
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White Mesa Mill Cell 2 Radon Flux
4.0 METHODOLOGY
The radon model used for calculations in this report is that described in the U.S. NRC Regulatory
Guide 3.46 (1989) for Calculation of Radon Flux Attenuation by Earthen Uranium Mill Tailings
Covers. This methodology was used to calculate radon flux from the bare tailings, and also to
estimate the cover depth required to keep the radon flux below the limit of20 pCi m·2 s·1 as more
of the tailings become dry.
4.1 CALCULATION METHODOLOGY
The NRC model uses a one-dimensional steady-state gas diffusion model. Fundamental
parameters used in this model include the thicknesses, densities, specific gravities, moisture
contents, radium activities, radon diffusion coefficients, and radon emanation coefficients of the
materials (tailings and cover).
Table 4-1 lists all the parameters and equations used by the NRC model, as well as parameter
values specitic to Cell 2 as provided in MWH (2011). With the parameters provided in Table
4-J, assuming a dry tailings thickness of 10 ft. and a cover thickness of 3 ft. with a low
compaction (80%) random fill, a diffusion coefficient of about 0.03 cm2/s can be estimated. For
this scenario, a theoretical radon flux of about 241 pCi m·2 s·1 would be estimated, which is
higher than the actual measmed radon flux in Cell 2. Jn order to refine the assumptions used in
the model, the model was adj usted to take into account the results of the test pit field work
refeiTed to in Section 3.3 above, as discussed in Section 4.2 below.
4.2 ANALYSIS OF TEST PIT DATA
Radon flux values estimated using the parameter values provided in Table 4-1 appear,
sometimes, to be several times higher than those estimated from recent test pit data refen·ed to in
Section 3.3 above. Therefore, an average soi l diffusion coefficient (De) was back-calculated for
the average cover thickness and average dry tailings thickness (4.35 ft. and 11.74 ft.,
respectively) at 0.0086 crn2/s using all 2011/2012 samples. Using the average De for individual
sampling points generally produces fluxes consistent with those measured, except for sample
D25, where a thick dry tailings and little cover has actually resulted in a flux lower than
expected. This could be the result of a local variation in the characteristics of the soil cover, e.g.
degree of compaction or moisture content. The average De was modified by removing sample
D25 from the averaging and a modified average De of 0.0098 cm2/s was back-calculated. Figure
4-l compares the estimated radon flux (based on the modified average De) to the measured
fluxes, which shows a reasonable coiTelation.
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White Mesa Mill Cell 2 Radon Flu.;-c
Although further adjustments are possible, given the overall uncertainly, a nominal diffusion
coefficient of 0.01 cm2/s would seem reasonable, based on the test pit data. This diffusion
coefficient is lower than previously estimated (at 0.03 cm2/s in Section 4.1) for unconsolidated
random fill cover and thus provides a more effective radon barrier than pre viously considered.
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White Mesa Mill Cell 2 Radon Flux
T ABLE 4-1 PARAMETER VALUES AND EQUATIONS
Description Parameter
Specific activity of radium-226 in R,
tailings
Dry bulk mass density of tailings Pt
Radon emanation coefficient for the E,
tailings
Radon decay constant f,.
Specific gravity of tailings G,
Mass density of water Pw
Long-term average moisture content w,
of tailings after dewatering
Porosity of tailings 111
Moisture saturation fraction of mt
tailings
Diffusion coefficient for radon in the D,
total pore space of the tailings
Thickness of tailings xt
Radon tlux fi·om bare tailings source J,
Dry bulk mass density of soil cover Pc
Specific gravity of soil cover Gc
Long-term average moisture content We
of soil cover
Porosity of cover soil llo
Moisture saturation fraction of cover me
soil
Diffusion coefficient for radon in the De
total pore space of the tail if!gs
Equilibrium distribution coefficient k
for radon in water and air
rnverse relaxation length for cover be
soil
Thickness of soil cover Xc
Interface constant tor tailings at
Interface constant for cover soil ac
lnverse relaxation length for tailings b,
Radon flux from cover Jc
Equations based on NRC ( 1989):
Equation 4: 00=1-Pel Gc-Pw
Equation 7: D= 0.07 exp [-4(m-m.n2 + m5)]
Equation 8: me= 0,01 Pc· WJ nc. Pw; m,= 0.01 Pt· WJ n,. Pw
Equation 9: 11= 104 R1• p, .E1 ~(A..D1). tanh (X, "(AID,))
Equation I 0: be= ../AIDe; b1 =~AID,
Equation II: ac= n/. De [1-(1-k)mcl2; at= n12• D, [1-(1-k)m.f
Unit Selected
Value
pCi/g 981
g/cm3 1.19
-0.19
s·t 2.10 X
10'6
-2.75
g/cmJ I
dry wt. percent 6
-0.57
-0.125
cm'/s 0.0499
em 305
pCi m''s· 691
g/cm3 1.50
-2.67
dry wt. percent 7.8
-0.44
-0.265
cm~/s 0.030 *
pCi/cmJ water 0.26
per pCi/cm3 air
em·' 0.0084
em 91
cm'/s 0.013
cm2/s 0.0037
em 0.0065
pCi m·2 s'1 241
Equation 12: 10=(2 J,.exp(-bc..Xcll/ (1+ (...f(aJac).tanh(b,.X,))+(l-(-l(aJac).tanh(b,.X,)).exp(-2bc.Xcll
* Modified later (Section 4.2)
350496-011 -March 2013 4-3
Comment Equation
no.
Section 2.1 -
MWH20ll -
MWH201 1 -
NRC 1989 -
MWH2011 -
NRC1989 -
NRC 1989; MWH -
2011
MWH2011 -
-Equation 8
-Equation 7
I 0 ft -
-Equation 9
MWH2011 , 80% -
MWH20ll -
MWH201l -
-Equation 4
-Equation 8
-Equation 7
NRC1989 -
-Equation 10
3 ft soil (80% -
compaction for
sample calculation
referred to in
Section 4.1)
-Equation 11
-Equation II
-Equation 10
-Equation 12
SENES Consultants Limited
White Mesa Mill Cell 2 Radon Flux
FIGURE 4-1 ESTIMATED RADON FLUX BASED ON TilE RECOMMENDED AVERAGE DIFFUSION
COEFFICIENT (0.01CM2/S) COMPARED TO MEASURED FLUXES
140
0 Radon-2011
120 -Radon-2012 • -100 ---er-Radon-estim ated ... ill
";'
E 80 iJ c. -)( 60 :::s u::
s::
0 40 "0
1'0 a::
20 0 [il
(!]
0
022 025 028 030 048 085 037 044 042 077
Table 4-2 compares the U.S.EPA's HVLs with the ones estimated for the two soil covers
characterized by MWH (2011), and the one with an average De ofO.Ol cm2/s, which shows that
the actual interim cover with an average De of 0.01 cm2/s is performing with an attenuation
coefficient between that for the MWH 80% and 95% compaction and greater than the attenuation
coefficient for EPA's compacted moist soiL
TABLE 4-2 RADON ATTENUATION OF VARIOUS COVERS
Cover Moisture HVL Attenuation
(%) (meters (m)) coefficient (lim)
U.S. EPA 1986
Sandy soil 3.4 1 0.7
Soil 7.5 0.75 0.9
Soil 12 .6 0.5 1.4
Compacted moist soil 17 0.3 2.3
Clay 21.5 0.12 5.8
Estimated from Cell 2 Data
80% compaction (MWH) 7.8 0.55 1.55
95% compaction (MWH) 7.8 0.21 3.27
Average De (O.Olcm2/s) -0.43 2.47
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White Mesa Mill Cell 2 Radon Flux
4.3 RADIUM-226 ACTIVITY IN T A fLINGS
As discussed in Section 3.1 , there is some uncertainty about the radiuro-226 activity present in
the tailings. A sensitivity analysis was therefore completed assuming ± 25% variation in the
average activity proposed by MWII (2011) of981 pCi/g. Average De's were back-calculated for
these two activities (736 and 1226 pCi/g) and were applied to individual sample locations. The
back-calculated De's were 0.012 and 0.0084 cm2/s for the lower and higher activities,
respectively. Estimated and observed radon fluxes for the three radium-226 activities (and their
corresponding De's) are shown on Figure 4-2. It is noted from this figure in general the radon
flux (out of soil) is not very sensitive to radium-226 activity in tailings and, moreover, does not
materially reduce the scatter in the data which most likely arises from a simplification of the
actual physical conditions in Cell2.
FIGURE 4-2 SENSITIVlTY OF ESTIMATED RADON FLUX TO RADIUM-226 ACTIVITY IN
TAILINGS
140 ~--------------------------------------~~
120
~ 100 v,
N E
u 80 Q. -
u::
"0 60 2:! IU E
·~
1.1.1 40
20 -
! 022
• 042 ,
,. ,
, ,
t 07•7
'028
,
• 85 ,. " • 030
{ , "
, , , ,
• 044
I ,
0 ~~----.-----.-----r---~r----,-----,-----;
0 20 40 60 80 100 120 140
Observed Flux (pCi.m·2S·l)
Note: the points show fluxes estimated for an average radium-226 activit~ (981 pCi/g), while the bars represent the
range of fluxes calculated using± 25% variation in the average activity.
The dashed line represents a perfect correlation between estimated and observed tluxes.
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White Mesa Mill Cell 2 Radon Flux
5.0 RESULTS AND CONCLUSIONS
5.1 TAILINGS DEWATERING AND RADON FLUX
Based on test pit data, the nominal average thickness of the random fill cover is approximately
4.35 feet. Figure 5-l shows the theoretical effect of increasing depths of dry tailings up to a
maximum depth of 30 feet to account for the dewatering process. It is evident from the figure
that with the current depth to water table (thickness of dry tails) of about J 1.74 ft., the anticipated
radon flux is nearly at its theoretical maximum. The corresponding theoretical radon flux for the
assumed conditions is about 40 pCi m-2 s·1, slightly conservative compared to the 2012 measured
average of 25.9 pCi m-2 s-1• However, given the available data, the theoretical radon flux of
40 pCi m-2 s-1 is considered to be a fairly close approximation to the actual measured radon flu x.
FIGURE 5-1
800
700
... "2 600 -
')I
E 500 -u c. -400 X :l ;;:::
Ql 300 b.O ro ...
Ql 200 > <(
100
0
0
ESTIMATED AVERAGE RADON FLUX FROM BARE AND COVERED TAILINGS
5 10
~Average flux (bare tailings)
-Average flux (under 4.35 ft cover)
15 20 25
Dry tailings thickness (ft)
30
Figure 5-2 shows the theoretical estimated flux from the cutTent dry tailings for different cover
thicknesses. With 4 to 5 ft. of cover (average current thickness), the estimated flux is about
40 pCi m-2 s-1• Again, this theoretical estimated flux is considered conservative and, based on
the fact that current average .flux at approximately 4.35 feet of cover is 26 pCi m"2 s·', not 40 pCi
m·2 s·', appears to conservatively overstate the actual radon flux at each cover thickness. It
should be noted that the average estimated flux assumes average conditions exist across the full
Cell 2; however, as illustrated by Figure 5-2 there is some variability and as can be inferred from
the figure, only a small change in average cover thickness would be needed to result in the
observed average flux from 2012 of26 pCi m-2 s·1•
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White Mesa Mill Cell 2 Radon Flux
FIGURE 5-2 ESTIMATED FLUX VERSUS COVER D EPTH FOR THE CURRENT DRY TAILINGS*
300 ~--------------------------------------------------~
250
;::;--200 '"!
~ E d 150
c.. -X :J L:L 100
so
0
1 2 3
Average Cover Depth ( 4.35 fl)
Theoreti_cal Average flux at 4.35 11=40
4 5 6 7 8
Cover depth (ft)
9
* An average dry tailing thickness of 11.74 ft.
5.2 R EQUIRED COVER TIIIC KNESS
As suggested earlier, the radon flux from the bare surface of the tailings will continue to increase
to some maximum value limited by the balance between increased radon potential and radon
decay as dewatering continues with progressive lowering of the water table within the tailings.
However, it can also be infetTed from Figure 5-1 and the test pit data, which suggests average
dry tailings of approximately 11.74 ft., that the rate of increase in radon flux from the surface of
the cover with decreased water level (i.e., increased dry tailings thickness) i.s decreasing. This
also suggests that the cover thickness is approaching its theoretical limit.
In 2012, the average flux was measured at about 26 pCi m-2 s·1• The theoretical model
conservatively predicts the radon flux under current conditions to be 40 pCi m·2 s·1•
As previously noted, the current cover thickness varies between 2.4 and 9 feet in various
locations, with an average of 4.35 ft. Based on the theoretical model, Table 5-1 shows the
estimated cover thickness required to maintain the surface flux at or below 20 pCi m·2 s·1 as the
thickness of the dry tailings increases.
The estimated cover thicknesses in Table 5-1 are based on the theoretical model, which predicts
that a cover thickness of 5.79 feet would be required to achieve a radon flux of 26 pCi m·2 s-1,
when in reality the current average cover of 4.35 ft. appears to result in that radon tlux rate.
Table 5-1 can therefore be considered to set a theoretical upper bound, based on the data
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White Mesa Mill Cell 2 Radon Flux
available, and estimates that a total average thickness of 6.39 ft. would be sufficient to limit
radon flux to 20 pCi m·2 s·1, regardless of the depth of dry tailings. In fact, based on the Mill's
actual experience and test pit results, a thickness of less than 6.39 feet may prove to be adequate
to achi eve that objective.
Data in Table 5-1 suggests that in order to achieve an overall radon flux of 20 pCi
m·2 s·1, irrespective of thickness of dry tailings, it would be necessary to add an average of about
2 feet of random :fill increasing the cover depth to about 6.4
TABLE 5-1 ESTIMATED REQUIRED THICKNESS OF COVER
Dry Tailings Average Flux from Average Flux Required Cover Thickness*, ft.
Thickness, Bare Tailinys, under 4.35 ft. of to achieve to achieve
ft. pCi m·2 s· Cover, pCi m·2 s·1 20 oCi.m"2s·1 26 oCi.m-2s·1
1I 700 49.5 6.38 5.79
12 706 49.6 6.38 5.79
13 710 49.7 6.38 5.80
14 713 49.7 6.38 5.80
15 714 49.7 6.39 5.80
20 718 49.8 6.39 5.80
25 718 49.8 6.39 5.80
30 718 49.8 6.39 5.80 .. * Jnclustve of extstmg cover
As discussed in Section 2.2, a simple method for estimating the required cover thickness is to use
the half-value layer (HVL) which is the thickness of material that reduces radon emissions to
one-half of its initial value. For a nominal average an average diffusion coefficient of
0.01 cm2/s, the HVL can be estimated at 0.43 m (1.4 ft.). The HVL can be used to calculate the
impact of any depth of soil cover on radon reduction. For example in order to reduce the cunent
average radon flux of 20 pCi m·2 s·1 (average measured in 2012) to 20 pCi m·2 s·1, a 30%
reduction in flux is required (radon transmission or T=0.7). The soil thickness (t) to achieve this
can then be calculated as t=-IIVL * ln(T)/ 0.693 = -0.43* ln(0.7)/0.693= 0.16 m = 0.5 ft. Thus,
an additional 0.5 ft. of random fill cover (at between 80% and 95% compaction) would be
expected to reduce the average radon Oux from the cover of Cell 2 to below 20 pCi m·2 s·1•
If the rate of increase of radon nux per foot decrease in water level of 3 to 5 pCi m·2 s·1observed
between 2009 and 2012 is representative, noting that any such rate is expected to decrease as
dewatering continues, and dewatering has been progressing at the rate of approximately one to
two feet per year, it would be reasonable to expect that radon fl ux will increase by about 3 to
1 0 pCi m -l s -I over the next year as a result of dewatering. Adding this expected increment to the
existing flux rate of 26 pCi m·2 s·1 would result in an expected flux rate of 30 to 36 pCi m·2 s·1.
Applying the foregoing fonnula, approximately 1.0 ft. of random fill (at between 80 and 95%
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White Mesa Mill Cell 2 Radon Flux
compaction), over the existing cover would be expected to reduce the average radon flux from
the cover of Cell 2 to below 20 pCi m·2 s·1•
Further, as previously noted, the current cover thickness varies between 2.4 and 9 feet in various
locations, with an average of 4.35 ft. In order to achieve an overall radon flux of 20 pCi m·2 s·',
and assuming parameters and conditions as outlined above, an average of an additional (about)
2 feet of random fi ll (at between 80 and 95% compaction) cover would reasonably be expected
to be sufficient to reduce the surface radon flux to below 20 pCi m·2 s·1, regardless oft11e depth of
dewatered tails.
The dewatering operation is expected to take several years to complete and if addition of random
fill is not practicable, exceeding the radon flux standard will be an unavoidable but temporary
consequence of the dewatering actions required to reclaim Cell 2.
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White Mesa Mill Cell 2 Radon Flux
6.0 REFERENCES
MWH Americas Inc. 2011. Pages from the Updated Tailings Cover Design Report.
Tanner, A.B. 1964. Radon Migration in the Ground: A Review". In the Natural Radiation
Environment, ppl61-190, J Adams and W. Lowder. Eds, University ofChicago Press.
Tell co Environmental 2012. National Emission Standards for llazardous Air Pollutants 2012
Radon Flux Measurem ent Program White Mesa Mill.
TIT AN Environmental 1996. Pages from the Tailings Cover Design report.
United Nations Scientific Committee on the Effects of Atomic Radiation (UNSCEAR) 2000.
Sources and Effects of Ionizing Radiation -Volume I: Sources. Report to the General
Assembly, with Scientific Annexes, United Nations, New York.
United States Environmental Protection Agency (U.S. EPA) 1982. Final Environmental Impact
Statement for Remedial Action Standards for inactive Uranium Processing Sites (40 CFR
192)-Volume 1. EPA 520/4/82/013-1 , October.
United States Environmental Protection Agency (U.S. EPA) 1986. Background information
document. Standard for Radon-222 Emissions from Licensed Uranium Mill Tailings.
EP A/520/1 -86-009.
United States Envitomnental Protection Agency (U.S. EPA) 1998. Regulations as found in 40
CFR 61 Subpart W National emission standards for radon emissions from operating mill
tailings. April.
United States Nuclear Regulatory Commission (NRC) 1989. Regulatory Guide 3.64 Calculation
of Radon Flux Attenuation by Earthen Uranium Mill Tailings Covers. Jw1e.
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