DRC-2014-004182 - 0901a0688045b537

'tm ENERGY FUELS
Energy Fuels Resources (USA) Inc.
225 Union Blvd. Suite 600
Lakewood, CO. US, 80228
303 974 2140
www.energyfuels.com
VIA EMAIL AND OVERNIGHT DELIVERY
June 25, 2014
Mr. Bryce Bird
Director, Utah Division of Air Quality
State of Utah Department of Environmental Quality
195 North 1950 West
Salt Lake City, UT 84116
JUN
9/
DRC-2014-004182
Re: White Mesa Uranium Mill,
National Emissions Standards for Radon Emission from Operating Mill Tailings
Transmittal of May 2014 Monthly Radon Flux Monitoring Report for Cell 2 and Request
to Cease Monthly Sampling
Dear Mr. Bird:
This letter transmits Energy Fuels Resources (USA) Inc.'s ("EFRI's") radon-222 flux monitoring report
for May 2014 (the "Monthly Report") consistent with 40 CFR 61.254(b), for Cell 2 at the White Mesa
Uranium Mill (the "Mill"). Included with this Monthly Report is a Radon Flux Measurement Program
Report, dated May 2014, prepared by Tellco Environmental (the "Tellco May 2014 Monthly Report").
The Tellco May 2014 Monthly Report indicates that for the month of May 2014, the average radon flux
from Cell 2 was 16.7 pCi/(m2 -sec), which is lower than the 20 pCi/(m2 -sec) set out in 40 CFR
61.252(a).
As discussed in the attached Monthly Report, the radon flux from Cell 2 during 2012 was higher than
the 20 pCi/(m2 -sec) set out in 40 CFR 61.252(a). Although Cell 2 is no longer in operation, consistent
with 40 CFR 61.254b, EFRI chose to perform monthly radon flux monitoring beginning the month
immediately following submittal of the report for the year in non-compliance. The result of the 2013
radon-222 flux monitoring for Cell 2 was 20.4 pCi/(m2 -sec) (averaged over 9 monthly sampling events),
which slightly exceeds the 20 pCi/(m~ -sec). Monthly sampling for Cell 2 has been conducted since
April of 2013. A summary of the events that gave rise to EFRI's decision to monitor radon flux at Cell 2
monthly consistent with 40 CFR 61.254(b) is set out in Section 4.0 in the attached Monthly Report.
EFRI has submitted monthly reports from May 2013 through June 2014 summarizing the April 2013
through May 2014 monthly sampling at Cell 2. A summary of the monthly Cell 2 radon flux
measurements, as well as the date the EFRI monthly reports were submitted to the Utah Division of Air
Quality ("UDAQ"), is included as Table 1 to this letter.
EFRI began interim mitigation of radon flux from Cell 2 in 2013, as a result of the 2012 exceedance, by
applying one foot of additional soil cover to areas of Cell 2 with elevated radon. Details of the interim
radon mitigation cover construction activities and interim corrective actions are described in Section 7.1
and 7.2 of the attached Monthly Report, respectively. EFRI completed the first phase of the interim
N:\WMM\Required Reports\NESHAPS Reports\2014 Monthly NESHAPs reports\May 2014\transmitall letter April
2014.doc
Letter to B. Bird
June 25, 2014
Page 2 of 2
cover installation on 12 test areas in September of 2013. The effectiveness of the additional compacted
cover at the 12 test areas was evaluated over several months. The additional cover on the 12 test areas
was successful in achieving the desired reduction to 20 pCi/(m2-sec) or lower. As a result, EFRI applied
additional random fill at 90% compaction to other areas of Cell 2 to further reduce the radon flux
measurements.
As shown on Table 1, since the completion of the test areas in September of 2013, the monthly radon
flux sampling results for Cell 2 have been lower than 20 pCi/(rrf -sec), and therefore, the construction of
the interim radon mitigation cover can be considered successful. Due to the success of the interim cover
in reducing radon emissions from Cell 2, EFRI submitted a Request to Cease Monthly Sampling on May
30, 2014 with the April 2014 Monthly Report, but does not yet have written approval from UDAQ, and
therefore is submitting this report.
If you have any questions, please feel free to contact me at [phone].
Yours very truly,
Energy Fuelsnesources (USA) Inc.
Jaime Massey
Regulatory Compliance Specialist
cc: David C. Frydenlund
Phil Goble, Utah DRC
Dan Hillsten
Rusty Lundberg, Utah DRC
Jay Morris, Utah DAQ
Harold R. Roberts
Frank Filas
David E. Turk
Kathy Weinel
Director, Air and Toxics Technical Enforcement Program, Office of Enforcement, Compliance
and Environmental Justice, U. S. Environmental Protection Agency
Attachments
Table 1
Cell 2 Monthly Radon Flux Sampling
Sampling Event Result (pCi/(m2 -sec)) Monthly Report Submittal Date
2012 Average 25.9
April 2013 18.0 May 29, 2013
May 2013 22.6 June 20, 2013
June 2013 23.2 July 25,2013
July 2013 24.2 August 20, 2013
August 2013 30.2 September 23, 2013
September 2013 17.0 October 23, 2013
October 2013 19.0 November 15, 2013
November 2013 19.5 December 17, 2013
December 2013 10.0 January 15, 2014
2013 Average 20.4
January 2014 9.8 February 27, 2014
February 2014 11.0 March 27, 2014
March 2014 16.4 April 25, 2014
April 2014 13.3 May 30, 2014
May 2014 16.7 June 25,2014
Average since April 2013 17.9
ENERGY FUELS RESOURCES (USA) INC.
40 CODE OF FEDERAL REGULATIONS 61 SUBPART W
WHITE MESA MILL
SAN JUAN COUNTY, UTAH
TAILINGS CELL 2 MONTHLY COMPLIANCE REPORT FOR MAY 2014
Submitted June 25, 2014
by
Energy Fuels Resources (USA) Inc.
225 Union Blvd. Suite 600
Lakewood, Colorado 80228
[phone]
Table of Contents
1.0 Name and Location of the Facility 3
2.0 Monthly Report 3
3.0 Name of the Person Responsible for Operation and Preparer of Report 3
4.0 Background Information -- Summary of 2012 Annual Report 4
4.1 Facility History 4
4.2 Dewatering of Cell 2 4
4.3 Radon Flux Monitoring of Cell 2 4
4.4 Evaluation of Potential Factors Affecting Radon Flux 5
5.0 May 2014 Results 6
6.0 Other Information - Status of Proposed Updated Final Cover Design 6
7.0 Additional Information Required for Monthly Reports 7
7.1 Construction and Monitoring of Interim Cover Test Area, and Application of Additional Random
Fill 7
7.2 Interim Corrective Action 8
8.0 Certification 9
2
1.0 Name and Location of the Facility
Energy Fuels Resources (USA) Inc. ("EFRI") operates the White Mesa Mill (the "Mill"), located in
central San Juan County, Utah, approximately 6 miles (9.5 km) south of the city of Blanding. The Mill
can be reached by private road, approximately 0.5 miles west of Utah State Highway 191. Within San
Juan County, the Mill is located on fee land and mill site claims, covering approximately 5,415 acres,
encompassing all or part of Sections 21, 22, 27, 28, 29, 32, and 33 of T37S, R22E, and Sections 4, 5, 6, 8,
9, and 16 of T38S, R22E, Salt Lake Base and Meridian.
All operations authorized by the Mill's State of Utah Radioactive Materials License are conducted within
the confines of the existing site boundary. The milling facility currently occupies approximately 50 acres
and the tailings disposal cells encompass another 275 acres.
2.0 Monthly Report
Although Cell 2 is no longer in operation, this Report is being submitted as a monthly report for the
Mill's Cell 2 for May 2014, consistent with 40 Code of Federal Regulations (CFR) 61.254(b) applicable
to operating tailings impoundments.
A summary of the events that gave rise to EFRI's decision to file this monthly report consistent with 40
CFR 61.254(b) is set out in Section 4 of this Report. A summary of the radon emissions from Cell 2
measured in May 2014 is set out in Section 5 of this Report.
The monthly monitoring data for May 2014, consistent with 40 CFR 61.254(b), is provided in Attachment
1 to this Report, which contains the Radon Flux Measurement Program Report, dated May 2014, prepared
by Tellco Environmental (the "Tellco May 2014 Monthly Report"). The results are summarized in
Section 5 of this Report.
3.0 Name of the Person Responsible for Operation and Preparer of Report
Energy Fuels Resources (USA) Inc.
225 Union Boulevard, Suite 600
Lakewood, Colorado 80228
303.628.7798 (phone)
303.389.4125 (fax)
EFRI is the operator of the Mill and its tailings impoundments (Cells 2, 3, and 4A) and evaporation
impoundments (Cells 1 and 4B). The Mill is an operating conventional uranium mill, processing both
conventional ores and alternate feed materials. The "method of operations" at the Mill is phased disposal
of tailings. The annual radon emissions for existing impoundments are measured using Large Area
Activated Charcoal Canisters in conformance with 40 CFR, Part 61, Appendix B, Method 115,
Restrictions to Radon Flux Measurements, (Environmental Protection Agency ["EPA"], 2008). These
canisters are passive gas adsorption sampling devices used to determine the flux rate of Radon-222 gas
from the surface of the tailings material. For impoundments licensed for use after December 15, 1989
(i.e., Cell 4A, and 4B), EFRI employs the work practice standard listed at 40 CFR 61.252(b)(1) in that all
tailings impoundments constructed or licensed after that date are lined, are no more than 40 acres in area,
and no more than two impoundments are operated for tailings disposal at any one time.
Although Cell 2 is no longer in operation, EFRI is submitting this monthly compliance report consistent
3
with the standards in 40 CFR 61.254(b) applicable to operating tailings impoundments.
4.0 Background Information -- Summary of 2012 Annual Report
4.1 Facility History
Cells 2 and 3, which have surface areas of 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.
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 surface area of each cell not exceed
40 acres. For this reason, Cells 4A and 4B are not required to undergo annual radon flux monitoring.
Cell 4A receives the Mill's tailings sands. Cells 1 and 4B, receive solutions only, and are in operation as
evaporation ponds. Cell 3, which is nearly filled, receives the Mill's solid waste and 1 le.(2) material only.
Cell 2 is filled with tailings, is covered with an interim soil cover, and is no longer in operation.
4.2 Dewatering of Cell 2
The Utah Division of Water Quality issued Groundwater Discharge Permit ("GWDP") UGW-370004 in
2005. Under Part I.D.3 of the current GWDP, EFRI has been required to accelerate dewatering of the
solutions in the Cell 2 slimes drain. Dewatering of Cell 2 began in 2008. In mid-2011, changes were
made in the pumping procedures for slimes drain dewatering of Cell 2 that resulted in an acceleration of
dewatering since that time. As discussed in more detail below, studies performed by EFRI indicate that
the increase in radon flux from Cell 2 has likely been caused by these dewatering activities. No other
changes appear to have occurred in condition, use, or monitoring of Cell 2 that could have resulted in an
increase in radon flux from the cell.
The average water level in the Cell 2 slimes drain standpipe for each of the years 2008 through 2013
indicate that water levels in Cell 2 have decreased approximately 3.98 feet (5600.56 to 5596.58 fmsl)
since 2008. Of this decrease in water level, approximately 1 foot occurred between 2010 and 2011,
reflecting the improved dewatering that commenced part way through 2011, and approximately 2 feet
between 2011 and 2013, reflecting improved dewatering for all of 2012 and 2013.
4.3 Radon Flux Monitoring of Cell 2
Tellco performed the 2012 radon flux sampling during the second quarter of 2012 in the month of June.
On June 25, 2012, Tellco advised EFRI that the average radon flux for Cell 2 from samples taken in June
2012 was 23.1 pCi/(m2 -sec) (referred to in the Tellco report as pCi/m2-s), which was higher than the 20
pCi/(m2-sec) standard referred to in 40 CFR 61.252(a). The result of the 2012 radon-222 flux monitoring
for Cell 3 was 18 pCi/(m2 -sec). Cell 3, therefore, was in compliance with this standard for 2012. The
results of the 2013 Cell 3 radon-222 flux monitoring were discussed in the 2013 Annual Radon Flux
Monitoring Report for Cell 3 submitted on March 27, 2014.
4
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."
EFRI advised the Utah Division of Air Quality ("UDAQ"), by notices submitted on August 3 and
September 14, 2012, that EFRI planned to collect additional samples from Cell 2 in the third and fourth
quarters of 2012. These samples were collected on September 9, October 21, and November 21, 2012,
respectively. As the June 2012 monitoring for Cell 3 indicated that it was in compliance with the
standard, further monitoring of Cell 3 was not performed in 2012.
The result of the 2012 radon-222 flux monitoring for Cell 2 was 25.9 pCi/(m2 -sec) (averaged over four
monitoring events). The measured radon flux from Cell 2 in 2012 was therefore higher than the standard
of 20 pCi/(m2-sec) referred to in 40 CFR 61.252(a).
The Cell 2 and Cell 3 radon flux results were reported in EFRI's 2012 Annual Radon Flux Monitoring
Report (the "2012 Annual Report").
The provisions of 40 CFR 61.254(b) requires that:
"If the facility is not in compliance with the emission limits of paragraph 61.252 in the calendar
year covered by the report, then the facility must commence reporting to the Administrator on a
monthly basis the information listed in paragraph (a) of this section, for the preceding month.
These reports will start the month immediately following the submittal of the annual report for
the year in non-compliance and will be due 30 days following the end of each month."
This Report is being submitted as the monthly report for May 2014 for Cell 2, consistent with the
requirements set out in 40 CFR 61.254(b). Monthly monitoring will continue until US EPA or UDAQ
advises EFRI that such monthly monitoring need not be continued. As mentioned in the cover letter,
EFRI submitted a request to cease monthly sampling on May 30, 2014 with the April 2014 Monthly
Report, but does not yet have written approval from UDAQ. Therefore, EFRI is submitting this report.
4.4 Evaluation of Potential Factors Affecting Radon Flux
In an attempt to identify the cause of the increase in radon flux at Cell 2, EFRI conducted a number of
evaluations in 2013, including:
• Excavation of a series of 10 test pits in the Cell 2 sands to collect additional information needed
to ascertain factors affecting radon flow path and flux,
• Evaluation of radon trends relative to slimes drain dewatering,
• Development of correlation factors relating dewatering rates to radon flux, and
• Estimation of the thickness of temporary cover that would be required to reduce radon flux to
levels lower than 20 pCi/(m2-sec), during the dewatering process.
These studies and results are discussed in detail in EFRI's 2012 Annual Radon Flux Report and
summarized in the remainder of this section.
5
Slimes drain dewatering data indicate that a lowering of the water level in Cell 2 has resulted in an
increase in the average radon flux, and that 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/(rrT-sec) per each foot of change in water level. It is also noteworthy that the significant
increases in radon flux from Cell 2 which occurred between 2010 and 2011 and between 2011 and 2012
coincided with the periods of improved (accelerated) dewatering of Cell 2.
EFRI has evaluated these results and has concluded that the increase in radon-222 flux from Cell 2 in
excess of 20 pCi/(m2 -sec) is most likely the unavoidable result of Cell 2 dewatering activities mandated
by the Mill's State of Utah GWDP. This is due to the fact that saturated tailings sands attenuate radon
flux more than dry tailings sands, and the thickness of saturated tailings sands decrease as dewatering
progresses. There appear to have been no other changes in conditions at Cell 2 that could have caused
this increase in radon flux from Cell 2. These conclusions are supported by evaluations performed by
SENES 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 temporary cover
required to achieve the radon flux standard during the dewatering process.
SENES' evaluations were presented in a report provided as an attachment to EFRI's 2012 Annual Report.
SENES estimated a theoretical radon flux from the covered tailings at Cell 2 for various depths
(thicknesses) of dry tailings, and predicted future increases in radon flux as a function of decreases in
water levels.
In order to explore potential interim actions that could be taken to maintain radon flux at levels at or
below 20 pCi/(m"-sec), the SENES study also evaluated the extent to which radon emanations from the
cell can be reduced by increasing the thickness of the current interim cover on Cell 2.
5.0 May 2014 Results
Detailed results for May 2014 for Cell 2 are contained in the Tellco May 2014 Monthly Report. As
described in the Tellco May 2014 Monthly Report, monitoring was performed consistent with 40 CFR 61
Subpart W Appendix B, Method 115 radon emissions reporting requirements. The radon monitoring
consisted of 100 separate monitoring points at which individual radon flux measurements have been made
by collection on carbon canisters. The individual radon flux measurements were averaged to determine
whether they exceeded 20 pCi/(m2-sec).
The average radon flux for Cell 2 in May 2014 was reported by Tellco to be 16.7 pCi/(m2-sec).
6.0 Other Information - Status of Proposed Updated Final Cover Design
As part of developing the Mill's final reclamation plan required to achieve the radon flux standard of 20
pCi/(m -sec), a final engineered cover design was submitted by TITAN Environmental in 1996 and
approved by the US Nuclear Regulatory Commission ("NRC"). An updated final cover design for the
Mill's tailings system, submitted in November 2011, is under review by the Utah Division of Radiation
Control ("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.
On April 30, 2013, a meeting was held in Denver, Colorado to discuss specific issues identified in DRC's
February 2013 review comments, including, but not limited to, DRC's request for site-specific tailings
6
data and a probabilistic seismic hazard analysis ("PSHA") for the Mill. Representatives of DRC, DRC's
consultant (URS Professional Solutions, LLC), EFRI, and EFRI's technical consultant (MWH Americas,
Inc.) attended the meeting. During the meeting, EFRI proposed a tailings investigation to address the
request for site-specific tailings data. A work plan for this investigation was provided to DRC on June
24, 2013, and DRC provided approval of the work plan verbally to EFRI on September 12, 2013. The
tailings investigation was completed in October 2013 and subsequent laboratory testing of samples
collected was completed in April 2014. A Tailings Data Analysis Report summarizing the results of the
investigation is currently being prepared for submittal to DRC in June 2014. A PSHA for the Mill is
being prepared for submittal to DRC in June 2014 as well. Submission of responses to DRC's February
2013 review comments on Revision 5.0 of the Reclamation Plan are planned to be completed in 2014
after DRC's review of the Tailings Data Analysis Report and PSHA for the Mill. The results provided in
the Tailings Data Analysis Report and PSHA for the Mill will be used to update technical analyses to
address DRC's February 2013 review comments on Revision 5.0 of the Reclamation Plan. The responses
will also incorporate decisions made at the April 30, 2013 meeting on key issues related to Revision 5.0
of the Reclamation Plan.
7.0 Additional Information Required for Monthly Reports
Controls or Other Changes in Operation of the Facility
40 CFR 61.254(b)(1) states that in addition to all the information required for an Annual Report under 40
CFR 61.254(b), monthly reports provided under that section shall also include a description of all controls
or other changes in operation of the facility that will be or are being installed to bring the facility into
compliance.
Based on the evaluations described in Section 4, above, and as discussed during EFRI's March 27, 2013
meeting with UDAQ and DRC staff, in addition to the monthly monitoring reported in this Monthly
Report, EFRI has performed the following steps to ensure that radon emissions from Cell 2 are kept as
low as reasonably achievable and at or below 20 pCi/(m2-sec).
7.1 Construction and Monitoring of Interim Cover Test Area, and Application of Additional Random
Fill
i. EFRI constructed 12 test areas on Cell 2 to assess the effect of the addition of one foot of
additional soil cover. EFR applied one foot of random fill moistened and compacted by a dozer
to 12 circular test areas of approximately 100 to 120 feet in diameter. The total tested area is
larger than the single 100 foot by 100 foot area proposed in previous Cell 2 monthly radon flux
monitoring reports. Installation of 12 test areas containing the additional 1 foot of compacted soil
was completed by August 2, 2013. Wetting and re-compaction of all 12 areas was completed
prior to the start of the September 21, 2013 monthly flux monitoring event.
ii. The radon flux has been monitored monthly at 100 locations on Cell 2, including the 12 test
areas, since April 2013.
iii. The effectiveness of the additional compacted cover at the 12 test areas was evaluated over
several months. The additional cover on the 12 test areas was successful in achieving the desired
reduction to 20 pCi/(m2-sec) or lower. As a result, EFRI applied additional random fill at 90%
compaction to other areas of Cell 2 to further reduce the radon flux measurements.
7
Based on discussions with DRC, EFRI will proceed with the application of cover and will provide a letter
to DRC with information demonstrating that the application of soil cover is consistent with the design and
QC requirements of the proposed Reclamation Plan, currently under revision, on the understanding that
the application of cover will be credited toward the final cover design.
7.2 Interim Corrective Action
EFRI has taken the following additional steps to provide interim mitigation of radon flux from Cell 2.
EFRI has identified the areas of elevated radon flux associated with known sources of radiological
contamination at or near the surface of the cell cover. Specifically:
• Windblown tailings from Cell 3 which have been deposited on Cell 2 as Cell 3 is being closed
have been removed and re-buried in Cell 3. A berm approximately five feet high, extending the
length of the Cell 3 beach has been constructed at the edge of Cell 2, to prevent further carryover
of sands from Cell 3 onto the Cell 2 cover prior to closure of Cell 3.
• Any contaminated material near the surface of Cell 2 has been reburied.
• Additional cover material has been added to each of 12 identified areas of elevated flux on Cell 2.
• Additional cover material has been added to other areas with elevated flux on Cell 2.
• Monthly radon flux monitoring to assess the effectiveness of the above actions is ongoing.
a) Facility's Performance Under Terms of Judicial or Administrative Enforcement Decree
The Mill is not under a judicial or administrative enforcement decree.
8
8.0 Certification
I 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, I believe that the submitted information is true, accurate and complete. I am aware that there
are significant penalties /for submitting false information including the possibility of fine and
imprisonment. See*lyB, UJ5.C. 1001.
Signed: Jl \ /jT Date: "%^e 2JT; ~>V/^
David C. Ewyae^ilun^
Senior VicWresident, General Counsel & Corporate Secretary
ATTACHMENT 1
National Emissions Standards for Hazardous Air Pollutants
2014 Radon Flux Measurement Program
May 2014 Sampling Results
National Emission Standards for Hazardous Air Pollutants
2014 Radon Flux Measurement Program
White Mesa Mill
6425 South Highway 191
Blanding, Utah 84511
May 2014 Sampling Results
Cell 2
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 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 5
6.3 Background and Sample Counting 5
7. QUALITY CONTROL (QC) AND DATA VALIDATION 5
7.1 Sensitivity 6
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)
1. INTRODUCTION
During May 19-20, 2014 Tellco Environmental, LLC (Tellco) of Grand Junction, Colorado, provided
support to Energy Fuels Resources (USA) Inc. (Energy Fuels) to conduct radon flux measurements at
its White Mesa Mill site 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 to represent the year or making
multiple measurements over a one year period (e.g., weekly, monthly, or quarterly intervals).
Energy Fuels is presently performing radon flux measurements on a monthly basis at Cell 2. Prior to
2012, Energy Fuels had been making a single set of measurements to represent the radon flux each
year; however, as the radon flux levels began exceeding the regulatory standard of 20 picoCuries per
square meter per second (pCi/m2-s) in 2012, Energy Fuels responded by opting to make the radon flux
measurements on a more frequent basis.
Also, in response to the increase in the radon flux rates, Energy Fuels has placed approximately
19,432 cubic meters of additional material, varying in depth from approximately 31-61 centimeters,
throughout an area of approximately 50,130 square meters (nr). In March 2014, Energy Fuels
suspended the placement of additional cover materials at Cell 2 because the average flux rate had been
below the regulatory standard for several months.
Tellco was contracted to provide radon canisters, equipment, and canister-placement personnel as well
as lab analysis of samples collected. Energy Fuels personnel provided support for loading and
unloading charcoal from the canisters. This report details the procedures employed by Energy Fuels
and Tellco to obtain the results presented in Section 9.0 of this report. This report presents the radon
flux measurements results only for Cell 2 for May 2014; Cell 3, which is presently on a quarterly
sampling schedule, was not sampled during May 2014.
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 and
vanadium from feed stocks. Processing effluents from the operation are deposited in 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 m2, has been filled and covered with interim
cover. This cell is comprised of one region, an interim soil cover of varying thickness, which requires
NESHAPs radon flux monitoring. There were no apparent exposed tailings within Cell 2 during the
April 2014 sampling.
Cell 3, which has a total area of approximately 288,858 m2, is nearly filled with tailings sand and is
undergoing pre-closure activities. This cell is comprised of two source regions that require NESHAPs
:
radon monitoring: a soil cover region of varying thickness and an exposed tailings "beaches" region.
The remaining area is covered by standing liquid in lower elevation areas.
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 U.S. 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 air from an
existing uranium mill tailings pile shall not exceed an average of 20 pCi/m2-s for each pile (or cell).
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." Cell 1 is
completely covered with standing liquid and therefore no radon flux measurements are required on
Cell 1. 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 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 with 40 CFR, Part 61, Appendix B, Method 115, Restrictions to Radon Flux
Measurements, (EPA, 2013). 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 10-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 M- inch thick layer of foam and
secured with a retaining ring under 1 Vi inches of foam (see Figure 1, page 10).
One hundred sampling locations were distributed throughout Cell 2 (consisting 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 from the principles of radioactive decay.
After approximately 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 Tellco laboratory in Grand Junction, Colorado for analysis. Upon completion of on-
site activities, the field equipment was alpha and beta-gamma scanned by Energy Fuels Radiation
Safety personnel for possible contamination resulting from fieldwork activities. All of the field
equipment used was subsequently 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 110°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". 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
On May 19, 2014, 100 sampling locations were spread out throughout the Cell 2 covered region. The
same sampling locations that were established for previous samplings of Cell 2 were used for the
placement of the canisters for May 2014, although the actual sample identification numbers (IDs) are
different. An individual ID was assigned to each sample point, using a sequential alphanumeric
system indicating the charcoal batch and physical location within the region (e.g., G01...G100). 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 these canisters were kept inside an airtight plastic
bag during the 24-hour testing period.
5.3 Sample Retrieval
On May 20, 2014 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
3
transport. Retrieval date and time were recorded on the same data sheets as the sample placement
information. The blank samples were similarly processed.
All 100 charcoal samples from Cell 2 covered region were successfully retrieved and containerized
during the retrieval and unloading process.
Tellco personnel maintained custody of the samples from collection through lab analysis.
5.4 Environmental Conditions
A rain gauge and thermometer were placed within Cell 2 to monitor rainfall and air temperatures
during sampling; additionally, Energy Fuels maintains an onsite rain gauge.
In accordance with 40 CFR, Part 61, Appendix B, Method 115:
• Canisters were not placed within 24 hours of rainfall at the site.
• There was no rainfall at the site after the placement of the canisters.
• The criteria regarding minimum ambient air temperature and frozen ground do not apply
when performing sampling on a monthly basis; however, the minimum air temperature
during the sampling period was 42 degrees F, and the ground was not frozen at any of the
sample locations.
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 (Nal(Tl)) detector.
• Lead shielded counting well approximately 40 cm deep with 5-cm thick lead walls and a 7-
cm thick base and 5 cm 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.
4
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 personnel checked for damaged or unsealed containers and verified that
the data sheet was complete.
All of the 100 sample containers and 5 blank containers received and inspected at the Tellco analytical
laboratory were ultimately verified as valid and no damaged or unsealed containers were observed.
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/Teledyne system with shielded counting 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 gamma 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 10 percent of the containers counted were selected for recounting. These
containers were recounted on the next day 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, 2013) were
attained.
5
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. Analysis of the five
blank samples measured radon flux rates ranging from approximately 0.00 to 0.02 pCi/m2-s, with an
average of approximately 0.01 pCi/m2-s. The lower limit of detection (LLD) was 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
measurements, expressed as relative percent difference (RPD), ranged from less than 0.1 percent to
8.0 percent with an overall average precision of approximately 2.6 percent RPD.
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 -3.2 percent to -0.2 percent. The arithmetic average bias of the lab
control sample measurements was approximately -1.6 percent (see Appendix A).
7.4 Completeness
All 100 of the samples from the Cell 2 cover region were verified, representing 100 percent
completeness.
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 rates were calculated by a database computer program. The algorithms utilized
by the data base program were as follows:
Equation 8.1:
2 N
pCi Rn-222/m sec = [Xs*A*b*0.5(d/9175)]
6
where: 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:
0.1699, for M-01/D-21 and
0.1702, for M-02/D-20
= decay time, elapsed hours between sample mid-time and count mid-time
= area of the canister, nr
Equation 8.2:
Error,2cr = 2x
Gross Sample, cpm Background Sample,cpm
H
Sample Count,t,min Background Count,t,min
Net,cpm
x Sample Concentration
Equation 8.3:
LLD 2.71 +(4.65MS„)
[Ts*A*b*0.5(d/9T75)]
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:
0.1699, for M-01 /D-21 and
0.1702, for M-02/D-20
d = decay time, elapsed hours between sample mid-time and count mid-time
A = area of the canister, nr
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 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:
Ji Ai + . . . J2A2 [+1 • • • J,A,
Js =
A,
Where: Js = Mean flux for the total pile (pCi/m2-s)
J, = Mean flux measured in region i (pCi/m2-s)
A, = Area of region i (m2)
At = Total area of the pile (m2)"
7
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 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 Appendix C)
(a) The mean radon flux for the Cell 2 region at the site is as follows:
2 2
Cell 2 - Cover Region = 16.7 pCi/m -s (based on 270,624 m 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 Cell 2 is as follows:
Cell 2= 16.7pCi/m2-s
(16.7)(270.624) = 16.7
270,624
As shown above, the arithmetic mean radon flux of the samples for Cell 2 at Energy Fuels' White
Mesa milling facility is below the U.S. Nuclear Regulatory Commission and EPA standard of 20
pCi/m2-s. The May 2014 sampling results for Cell 2 are higher than the April 2014 results.
Appendix C presents the 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, NT1S #PB86-
161874, January 1986.
U. S. Environmental Protection Agency, Title 40, Code of Federal Regulations, July 2013.
U. S. Nuclear Regulatory Commission, Radiological Effluent 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 2013.
9
Figure 1
Large Area Activated Charcoal Canisters Diagram
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10
Appendix A
Charcoal Canister Analyses Support Documents
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CHARCOAL CANISTER ANALYSIS SYSTEM
SITE LOCATION: WkV4ct-PV> W , gl^i^ S
CLIENT:
Calibration Check Log
Calibration Date: Due Date: System ID:
Scaler S/N: S > High Voltage: lO'ZS Window: 4.42 Thrshld: 2.20
Detector S/N: Source ID/SN: Source Activity:
Blank Canister Bkgd. Range, cpm: 2 O" = _ 8k to 154 3c = I?17) to H )
Gross Source Range, cpm:
Technician: £-t j-t^^
All counts times are one minute.
Date By Background Counts (1 min. each)
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CHARCOAL CANISTER ANALYSIS SYSTEM
SITE LOCATION;_
CLIENT: £-*0-fc/T>yy F^-f^ -6 S<7 Hv^S
System ID:
Scaler S/N:
Detector S/N:
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: ~ 0' / t)"^-1 Calibration Date: W 13 Due Date:
Window: 4.42 Thrshld: 2.20
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High Voltage
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Gross Source Range, cpm:
Technician:
All counts times are one minute.
Date
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CHARCOAL CANISTER ANALYSIS SYSTEM
SITE LOCATION. VA/IVI^ \\^90\ ^Un^^ ? CA~T
CLIENT: £-^^y FM*\5 %&JUUtft*5
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System ID: M~Ol~ /D~~3-Q Calibration Date: G> / ff / ! 3 Due Date: fl 1 ^
Scaler S/N: 3^1 SU 3 High Voltage: I fl"7 ^ Window: 4.42 Thrshld: 2.20
Detector S/N: QH~*S Source ID/SN: ^OP^/ Gj^Of Source Activity: • 3 r^Xl",
Blank Canister Bkgd. Range, cpm: 2 a
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Technician: £•—
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The acceptable ranges were determined from prior background and source check data.
CHARCOAL CANISTER ANALYSIS SYSTEM
SITE LOCATION: VWjg Ht-9\ 1 ll, Sl*^'^ , UC"T
CLIENT: &Y\ er~t^f fvA t\S ^SOM^VS £j4 5flr)
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_ High Voltage: j ° Window: 4.42 Thrshld: 2.20
Detector S/N: 0^-\ lb 37- Source ID/SN: R'tf'^/Cr § ~Q** Source Activity. S"3-3« p^-<
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/ Technician:
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#1 #2 #3 Avg. #1
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BALANCE OPERATION DAILY CHECK
Balance Model: ?P<"4 - 0 ~ j<r*gi rY) St*J. *\ 7. 3^7
Standard Weight (g): g. 00*O
Date Pre-check (g)
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Appendix B
Recount Data Analyses
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Sample Locations Map (Figure 2)
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