DRC-2013-002515 - 0901a068803928c2

^^^^
State of Utah
GARY R HERBERT
Governor
GREG BELL
Lieutenant Governor
Department of
Environmental Quality
Amanda Smith
Executive Director
DIVISION OF RADIATION CONTROL
Rusty Lundberg
Director
"DRC-2013-002515"
MEMORANDUM
TO:
THROUGH
FROM:
DATE:
SUBJECT:
File C-2010-98 Notice of LDS Flows at Tailings Cell 1
Phil Goble, Section Manager ^/^/^l I
Russell J. Topham, P.E.
June 20,2013
Cell 1 Liner Repairs. Radioactive Materials License UT1900479 (RML) and Groundwater
Discharge Permit (GWDP) UG370004; Energy Fuels Resources, Inc. (EFR) White Mesa
Mill, Blanding, Utah
Summary
As noted in a memorandum to this file dated September 25, 2012, EFR has completed repairs to the Cell 1
liner system. For most technical aspects of the repair, please refer to that memorandum. Based upon the
findings presented in that memorandum, on September 25, 2012 the DRC approved the repair efforts, but
opted to keep the file open until fluid levels exceeded the repair elevation for 30 days and monitoring
revealed no fluids in the leak detection system. The DMT Performance Standards Monitoring Report for
the 1st Quarter of 2013 contains data showing fluid levels above the elevation of the repairs for the entire
quarter (90 days), with no fluids observed in the leak detection system. No other issues identified during
the course of the project remain to be resolved.
Recommendation: Evidence of satisfactory performance of the repair of the Cell 1 Liner having been
provided to the DRC, I recommend closing the project.
Chronology
Table 1 presents a chronological outline of the Cell 1 leak detection and liner repair event history from
June 2, 2010 to the present, as reconstructed from file documentation. Only significant events appear in the
table; not all telephone calls and email messages seemed important to a clear understanding ofthe problem
and resolution. Several documents in the file contain more detailed presentation of conversations and the
evolution ofthe project over time.
Pgte i Action,:^
June 2,2010 Field crew detects fluid in the leak detection system for Cell 1.
Daily (Monday through Friday) monitoring of fluid level in the leak detection
system commences.
195 North 1950 West • Salt Uke City, UT
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June 3, 2010 Fluid accumulation reaches a level sufficient to allow collection of a sample to
analyze for constituents present in tailings fluids, but absent in ground water.
Samples submitted to two laboratories for analysis.
Initial field pH test implicates Cell 1 as the source of the fluid.
Fluid extraction from the leak detection system commences to facilitate calculation
of leakage rates through the cell liner.
Work crews divert inflows to other tailings cells and begin transferring fluid to Cell
4A with intent to lower the fluid level in Cell 1. Over the next two months, as fluid
levels subside to an eventual low of 5613.40 feet above mean sea level. Areas
where liner wear is suspected are uncovered, and any detected damage is repaired.
DRC receives notification by telephone of tailings fluid detected in the Cell 1 leak
detection system.
June 9, 2010 DRC receives written notification (dated June 7,2010) of tailings fluid detected in
the Cell 1 leak detection system.
August 7, 2010 Fluid level reaches 5614.22 feet above mean sea level. Fluid detected in the leak
detection system.
August 8, 2010 DRC receives notification of fluid detected in the leak detection system of Cell 1,
August 10, 2010 Denison Mines adds a 6-foot extension to the Cell 1 leak detection system
standpipe to discourage introduction of debris.
Fluid transfer from Cell 1 to Cell 4A commences at "maximum transfer pump
rate," likely meaning the maximum rate that pumps then onsite could operate.
August 12,2010 In a teleconference, mill managers and DRC agree that the June 2 and August 7,
2012 identifications of fluid in the leak detection system comprise one event. Not
all damage had been repaired prior to reintroducing fluid to the cell.
August 18,2010 Denison Mines proposes a liner repair plan.
August 23,2010 Conference call between Denison Mines and DRC results in a list of adjustments to
the liner repair plan, introducing corrective actions to eliminate uncertainties over
the performance of the leak detection system.
August 30, 2010 Denison Mines submits revised liner repair/corrective action plan.
September 22, 2010 DRC approves corrective action plan.
October 22, 2010 Video inspection reveals debris in the Cell 1 and Cell 3 leak detection systems.
November 11,2010 Denison Mines submits inspection videos to the DRC.
December 1-2, 2010 Denison Mines removes debris from Cell 1 and Cell 3 leak detection system piping,
to the extent practicable, and performs video confirmation.
December 27, 2010 Denison Mines submits confirmation videos of the work completed on December 1
and 2, 2010.
March 31, 2011 The DRC requires installation of a replacement method of leak detection in Cells 1
and 3, as the method in use appears inadequate to satisfy Part II.C ofthe applicable
Ground Water Discharge Permit. The DRC also required placing an attached
cap/cover on the leak detection system standpipe further to prevent introduction of
debris into the system piping.
April 28, 2011 Via conference call, Denison Mines reports selection of alternative monitoring
equipment for the leak detection systems for Cells 1 and 3, and installation of
covers on the Cells 1 and 3 system standpipes.
May 10, 2011 The DRC requires a plan and schedule for installing new equipment and
implementing new monitoring methods for Cells 1 and 3 leak detection systems.
June 1,2011 Denison Mines submits photographs of Cell 1 and Cell 3 leak detection system
standpipes which show installed extensions and covers.
Denison Mines proposes equipment and schedule for installation of new liquid
level monitoring equipment in Cell 1 and Cell 3 leak detection systems.
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July 12,2011 The DRC conditionally approves leak detection system plans.
July 13,2011 Denison Mines installs the approved modifications to the Cell 1 and Cell 3 leak
detection systems.
September 1,2011 The DRC observes during a site inspection that the approved leak detection system
modification plans have been executed, i.e., the equipment has been installed.
September 8, 2011 Denison Mines submits documentation of successful installation and startup of the
new elements of the Cell 1 and Cell 3 leak detection systems, except that the
warning light on the leak detection system activates at 24 inches of fluid head, and
the pump activates at 18 inches of fluid head, rather than at initial detection.
October 14, 2011 Public comment opens on the license renewal for the White Mesa Mill. License
Condition 11.3 contains language requiring the system to activate an alarm when
the fluid head on the transducer reached 2 inches, and to activate the pump when
the fluid head reaches 12 inches.
August 27, 2012 The DRC receives the 2nd Quarter, 2012 DMT Standards Monitoring Report in
which Denison Mines details the completed Cell 1 liner repair project. In this
report, Denison Mines details how the project evolved from spot repair to total
replacement of sections of liner above 5613 feet above mean sea level along the
perimeter of the cell. Overlapping testing of the repair section seams demonstrated
successful completion of the repairs to industry quality assurance standards.
September 25, 2012 The DRC extends approval of the repair operation, but keeps the file open pending
30 days' exposure of the liner to fluid levels above the elevation of the repair zone.
March 31, 2013 The first quarter of 2013 concludes with fluid levels in Cell 1 having exceeded the
elevation of the repairs for the entire quarter, with no detection of fluid in the leak
detection system.
Analysis
Leak Detection System
The DRC conditionally approved modifications to the leak detection system of Cell 1 on July 12,2011.
The DRC sought two outcomes in the modifications: reliable detection of fluid entering the leak detection
system as early as possible; and, removing fluid from the leak detection system as soon as possible to
prevent or reduce contamination of underlying ground water resources. The current construction and
proposed license condition represent the best compromise between the ideal and the doable available at this
time.
The DRC would like to detect any fluid passing through the liner as soon as the leak occurs. The system in
place on June 2,2010 was sufficient to detect fluid leaking through the liner, but variability in the level
reached by the detection system led to doubts that the system detected leakage as early or as low in the
system as desired. Consistently reading the fluid status 2 inches above a transducer set at the lowest point
in the leak detection system provides more confidence and consistency in leakage detection, and in the
event of a leak, leakage rate calculations, than the system previously used. Electronic alternatives that
would not require buildup of fluid head over the sensor are much more prone to fouling, and therefore,
much less reliable. The system selected and installed appears to be the best available alternative to improve
reliability and accuracy of fluid level measurement.
When Denison Mines was required to upgrade the leak detection system, the DRC anticipated that the
associated pump would activate at the time fluid was detected. Pumps selected for the Cell 1 and Cell 3
leak detection systems needed to be chemical resistant and capable of moving fluid out ofthe leak
detection system quickly. Pump rates were selected to draw down the fluid level in the leak detection
system rapidly. This minimizes the fluid that could find its way into ground water aquifers below the cell.
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Ifthe pump breaks suction, damage to the pump can occur. A damaged pump draws less fluid, and may
become ineffective in reducing fluid levels. To prevent the pump from breaking suction too frequently,
Denison Mines designed the system to activate when 18 inches of fluid ccumulated above the sensor. The
DRC has included in License Condition 11.3, requirements that the pump activates once fluid head reaches
12 inches above the transducer. Formerly, the system required installation of a pump after detecting fluid.
The system now in place allows automated extraction of fluid immediately upon fluid activating the pump,
without waiting for crews to install and activate the pump. This improves protection of the environment by
enabling fluid extraction on a weekend or overnight without necessitating delay for crews to discover the
fluid in the system.
The design ofthe monitoring and fluid extraction systems represents an effort to optimize performance
while balancing competing objectives. Given the number of unknown factors being considered, such as
leakage rate, when a leak may develop, etc., the system currently installed represents a significant
improvement in protecting ground water resources and improving worker safety in the event of a leak.
Recommendation: The DRC should approve the leak detection system as currently equipped.
Liner Repair
As detailed in the chronology above, Denison Mines (now Energy Fuels) completed repair of the liner for
Cell 1 by mid-year 2012. The repairs entailed replacing a band of material around the cell above elevation
5613 above mean sea level. The repair effort took 2 years to complete. Repair joints were tested to industry
standard ASTM D-5641 with overlapping test sections on every seam. If leaks in the seams were detected,
crews removed the patch section involved and replaced it entirely. The repair report appears in the BAT
Performance Standards Monitoring Report for the second quarter of 2012, dated August 22, 2012 as
Attachment E. The DRC approved the repairs on September 25, 2012, but held the file open until such time
as fluid levels reached an elevation sufficient to challenge the repairs for 30 days. The BAT Performance
Standards Monitoring Report for the first quarter of 2013, dated May 29, 2013 provides evidence that fluid
levels had achieved sufficient elevation for the entire first quarter of 2013 without fluid entering the leak
detection system.
Recommendation: The DRC should close the file on the leak repair effort.