DRC-2020-001501 - 0901a06880bc75e3

ENERGYFUELS
January 16, 2020
Energy Fuels Resources (USA) Inc.
225 Union Blvd. Suite 600
Lakewood, CO, US, 80228
303 974 2140
p RC- 202.0- DO I 501 www.energyfuels.corn
Div of Waste Management
and Radiation Control
JAN 2 1 2020 Sent VIA EXPEDITED DELIVERY
Mr. Ty L. Howard
Director
Division of Waste Management and Radiation Control
Utah Department of Environmental Quality
195 North 1950 West
Salt Lake City, UT 84116
Re: Transmittal of the Energy Fuels Resources (USA) Inc. White Mesa Uranium Mill, Slimes Drain
Compliance Plan
Dear Mr. Howard:
Pursuant to Part I.H.1 of the Groundwater Discharge Permit ("GWDP") Energy Fuels Resources (USA) Inc.
("EFRI") must submit a Slimes Drain Compliance Plan by January 19, 2020 for Director review and approval.
Enclosed are two copies of the EFRI Slimes Drain Compliance Plan as required by Part 1.H.1 of the GWDP.
If you should have any questions regarding this submittal please contact me.
Yours very truly,
c:71<et,
ENERGY FUELS RESOURCES (USA) INC.
Kathy Weinel
Quality Assurance Manager
CC: David Frydenlund
Paul Goranson Logan Shumway
Scott Bakken
Terry Slade
White Mesa Uranium Mill
Slimes Drain Compliance Plan
Prepared by:
ENERGYFUELS
Energy Fuels Resources (USA) Inc.
225 Union Boulevard, Suite 600
Lakewood, CO 80228
January 16, 2020
Contents
1.0 INTRODUCTION 1
1 . 1 Background 1
2.0 PRECIPITATION AND CELL 2 TEST SECTION WATER BALANCE 2
3.0 CELL 2 SLIMES DRAIN FLUID ELEVATIONS AND PUMPING 2
3. 1 Background 2
3.2 Quality Assurance Evaluation and Data Validation 3
3.3 Slimes Drain Data 3
3.4 Alternative Dewatering Tests 4
4.0 CELL 2 PIEZOMETER MONITORING 5
5.0 CELL 2 SETTLEMENT MONITORING 5
6.0 SUMMARY AND CONCLUSIONS 5
6.1 Demonstration of Decreasing Fluid Trends in the Slimes Drain Recovery Tests 6
6.2 Evaluation of Piezometer Head Data to Demonstrate Net Dewatering 7
6.3 Demonstration of Decreasing Trends in Cell Settlement Monitoring 8
6.4 Radon Mitigation 8
6.5 Conclusion 8
FIGURES
Figure 1 Cell 2 Dewatering Phase 1 Well Location
Figure 2 Dewatering Well Construction
TABLES
Table 1 2018-2019 Site and Long-term Average Precipitation
Table 2 Cell 2 Cover Test Section Water Balance Quantities
Table 3 Slimes Drain Volume Pumped 2015 — 2019
Table 4 Piezometer Water Level Elevations During and After Phase 1 Cover Placement
Table 5 Cell 2 Top Surface Settlement Measured Between April 2016 and December 2019
ATTACHMENTS
Attachment A Cell 2 Slimes Drain Elevation Graphs
Attachment B Cell 2 Piezometer Data
Attachment C Cell 2 Settlement Monitor Data
i
1.0 INTRODUCTION
Part I.D.3(b)(1) of the Groundwater Discharge Permit ("GWDP") provides that the Permittee shall
at all times maintain the average wastewater recovery head in the slimes drain access pipe to be as
low as is reasonably achievable ("ALARA"), in accordance with the currently approved Discharge
Minimization Technology ("DMT") Monitoring Plan.
Parts I.D.3, I.F.11, and II.G of the March 19, 2019 GWDP requires an annual assessment of the
slimes drain compliance. The annual assessments are completed and included in the Fourth
Quarter DMT Monitoring Report submitted annually on or before March 1 of each year.
Part I.H.1 of the GWDP requires:
"Within two (2) years after the effective date of this Permit Renewal (January 19,
2018), the Permittee shall submit a Slimes Drain Compliance Plan for Director
Review and Approval. The Plan shall include measures to ensure that wastewater
removal from the tailings cell slimes drain is effectively dewatering the tailings to
the extent practicable in order to allow placement of final cover within specified
time frames. The Plan may incorporate multiple methods to evaluate the
effectiveness of tailings cell dewatering and projected timelines for placement of
final tailings cell cover, including, but not limited to; 1. Demonstration of
decreasing fluid elevation trends as measured by slimes drain recovery tests; 2.
Evaluations of head data from piezometers installed in the affected tailings cell
demonstrating net dewatering, and 3. Demonstration of decreasing trends in cell
settlement monitoring. The Plan shall include specific measures for Tailings Cell
2 and will incorporate Tailings Cell 3 after initiation of dewatering operations."
This is the Energy Fuels Resources (USA) Inc. ("EFRI") Slimes Drain Compliance Plan (the
"Slimes Plan") contemplated by Part I.H.1 of the GWDP.
1.1 Background
On November 11, 2015, the Utah Department of Environmental Quality, Division of Waste
Management and Radiation Control ("DWMRC") recommended EFRI develop a plan to begin
reclamation of the tailings management cells. This plan consisted of placing the proposed cover
system presented in Reclamation Plan, Revision 5.1 (EFRI, 2016) on Cell 2 in two phases and
demonstrating acceptable cover performance via a performance monitoring program.
EFRI and DWMRC executed a Stipulation and Consent Agreement ("SCA") on February 23, 2017
defining the commitments and timeframes for completing placement of reclamation cover on Cell
2 and performance assessment of the cover system, in accordance with Reclamation Plan, Revision
5.1 (EFRI, 2016). Monitoring of cover performance is completed as required by the SCA and is
documented in various reports specified by the SCA. Cover performance reports are submitted
under separate cover in accordance with the schedule and requirements in the SCA.
1
Cell 2 Phase 1 cover placement commenced in April 2016 and was completed on April 20, 2017.
A cover test section for performance monitoring was constructed within the Cell 2 cover in the fall
of 2016 (concurrently with the Phase 1 cover placement). The cover for the test section includes
both the Phase 1 and Phase 2 cover system layers so as to evaluate the full cover profile during
monitoring.
2.0 PRECIPITATION AND CELL 2 TEST SECTION WATER BALANCE
Cell 2 cover performance monitoring per SCA requirements included installation of an on-site
meteorological station adjacent to Cell 2. Monthly precipitation data for the site for 2018 and 2019
are summarized in Table 1 along with the long-term average precipitation for the nearby Blanding,
Utah climate station (Station 420738). 2018 was a very dry year with the majority of precipitation
occurring in October. The site then had a significantly wet winter and spring in 2019, with three
months having over 200% higher than average precipitation. The wet conditions in 2019
temporarily caused increased water levels in the tailings in Cell 2 primarily on the west side of the
cell (see Section 4).
The cover test section has been monitored for percolation through the cover system since
installation. The test section water balance results for 2018 and 2019 are summarized in Table 2.
The monitoring results show the test section cover system is performing effectively with nearly all
precipitation being quickly returned to the atmosphere via evapotranspiration.
3.0 CELL 2 SLIMES DRAIN FLUID ELEVATIONS AND PUMPING
3.1 Background
GWDP Part I.D.3(b)(2) requires that effective July 11, 2011, the Permittee shall conduct a
quarterly slimes drain recovery test. The GWDP further requires that the test meets the following
minimum requirements: 1) includes a duration of at least 90-hours, as measured from the time that
pumping ceases, and 2) achieves a stable water level at the end of the test, as measured by three
consecutive hourly water level depth measurements with no change in water level, as measured to
the nearest 0.01 foot. It is important to note that prior to the July 2011 frequency change, monthly
testing was conducted from 2009 through the second quarter of 2011.
In accordance with the requirements described above, the quarterly slimes drain recovery head
monitoring data have been recorded and are routinely reported in the quarterly DMT Report. The
quarterly slimes drain head recovery tests include the date and time for the start and end of the
recovery test, the initial water level, and the final depth to stable water level for the quarter. All
measurements are made from the designated fluid measuring point. The fluid level measuring
point was surveyed by a licensed Utah land surveyor in Q3 2017 after the extension of the slimes
drain access pipe. The extension of the slimes drain access pipe was required due to the Cell 2
cover activities.
Cell 2 Phase 1 cover placement/construction commenced in April 2016. The Phase 1 cover
activities include the placement and compaction of approximately 4.5 feet of soil materials. These
cover placement activities caused an increase in the measured elevations of the Cell 2 slimes drain
fluids during cover construction. The cover materials surcharged the tailings mass, creating excess
pore pressure as the fluid was compressed along with the tailings. As a result of the increased pore
2
pressure, the phreatic surface of the Cell 2 slimes increased. The increase in elevations was
expected and is unavoidable during cover construction activities. Cover construction activities
also included the installation of a series of piezometers across Cell 2. Fluid levels are monitored
and recorded in the piezometers. Initially, fluid measurements in the piezometers were conducted
weekly. After the completion of the Phase 1 activities, the fluid measurements were conducted
monthly. The piezometer data are discussed below. The data indicate that increased fluid levels
in Cell 2 in late 2016/early 2017 was directly related to the placement of fill and cover construction
activities.
The slimes drain pump in Cell 2 is activated and deactivated by a float mechanism and water level
probe system. When the water level reaches the level of the float mechanism, the pump is
activated. Pumping then occurs until the solution level reaches the lower probe, which turns the
pump off. It is important to note that, as a result of the added cover materials and the increase in
solution elevations, additional volumes of solutions have been pumped since the commencement
of cover activities began.
3.2 Quality Assurance Evaluation and Data Validation
EFRI management has evaluated all slimes drain data collected, data collection methods, and all
related calculations required by the GWDP, and have verified the accuracy and reliability of both
the data and calculations reported.
As a result of its quality assurance evaluation and data validation review, EFRI has concluded that
the 2009, and 2010 monthly slimes drain tailings fluid elevation measurements, the 2011 monthly
(through June) and quarterly (July forward), and the quarterly 2012, 2013, 2014, 2015, 2016, 2017,
2018, and 2019 slimes drain tailings fluid elevation measurements to date meet the test
performance standards found in Part I.D.3(b)(2) and I.E.7(b) of the GWDP and can be used for
purposes of determining compliance with the requirements of the GWDP.
3.3 Slimes Drain Data
A graphical representation of the Cell 2 slimes drain recovery test data from 2009 — 2019 are
included in Attachment A. This graph shows an overall downward trend since 2009. An increase
in the slimes drain fluid level is noted in the fourth quarter of 2016, which is the result of the Phase
1 cover activities, which include the placement and compaction of approximately 4.5 feet of soil
materials. These cover placement activities caused the increase in the measured elevations of the
Cell 2 slimes drain fluids. The cover materials surcharged the tailings mass, creating excess pore
pressure as the fluid was compressed along with the tailings. As a result of the increased pore
pressure, the phreatic surface of the Cell 2 slimes increased, and the amount of fluid available for
pumping increased. The increase in elevations was expected and is unavoidable during cover
construction activities.
A graphical representation of the Cell 2 slimes drain recovery test data from December 2016
through 2019 is also included in Attachment A. This time period was chosen because the
maximum surcharge elevation was recorded in December 2016 mid-way through the Phase 1 cover
activities (April 2016 — April 2017). It is important to note that by December 2016, the majority
of the 4.5 feet of soil materials had been added to Cell 2 and the soil materials and the associated
3
weight of those materials caused the surcharge and the elevated December 2016 measurement.
This graph shows an overall downward trend after the December 2016 measurement. While some
minor increases are noted, the overall trend in slimes drain fluid elevations is downward. Minor
upticks are likely the result of increased precipitation in 2019 as noted in Section 2.0 above.
Table 3 shows the volume of fluids pumped from the Cell 2 slimes drain since 2015. As discussed
above, the cover materials surcharged the tailings mass, creating excess pore pressure as the fluid
was compressed along with the tailings. As a result of the increased pore pressure, the phreatic
surface of the Cell 2 slimes increased, and the amount of fluid available for pumping also
increased. An increase in the annual volume of fluid pumped is noted from 2016 through 2019.
When compared to the pre-cover (2015) levels, the 2016 — 2019 increase in fluids pumped directly
corresponds to the commencement of cover placement activities.
3.4 Alternative Dewatering Tests
During the summer of 2015, two different alternative dewatering designs were developed, with
one tested, for accelerating the consolidation and dewatering of the tailings slimes in Cell 2.
The first test was a simple trench excavated into the tailings sands/slimes, followed by a
measurement of the volume of fluid pumped from the trench. The intent was to compare the
volume of fluid pumped against the area of exposed tailings. An area of the 4 foot interim cover
was removed to allow access to the tailings surface. A trench approximately 2 feet wide by 15
feet long was excavated approximately 5 feet into the tailings sands. The trench was allowed to
fill with fluid seeping in from the tailings sands. Once the fluid level had stabilized, the solution
was pumped from the trench. As the solution was being pumped it became apparent that the
tailings sands were not stable and the trench soon collapsed. No further testing was possible at
that time and the trench was backfilled, and the interim cover replaced.
The second test was designed as a well point installation approximately 15 feet into the tailings
sands. It proposed installation of an 8 inch steel casing into the tailings sand. After casing
installation the tailings sands would be removed from the interior of the casing by the use of high
pressure water. A 6 inch slotted PVC casing would then be installed inside the steel casing. The
steel casing would then be removed and the tailings sands would consolidate around the slotted
PVC casing. Test locations are shown on the attached Figure 1, and the detailed design and
installation procedures are included in Figure 2. A review by EFRI management and operations
staff raised serious concerns about the construction feasibility and the effectiveness of the
installation. There were serious concerns about the ability to effectively push an 8 inch steel pipe
into 15 feet of tailings sand and concerns about damage to the cell synthetic liner should the pipe
penetrate too far. Evacuating the tailings from the interior of the casing was also a concern.
Assuming installation could be completed as designed, EFRI technical staff had serious concerns
that the slotted PVC pipe would quickly blind off without the installation of an adequately designed
and installed multi-layer filter between the tailings sands and the slotted PVC pipe. It was also felt
that the effective dewatering area of a single 6 inch slotted pipe would be so small as to not justify
the installation and pumping cost. Based on all these concerns, and the results of the above
trenching/pumping tests, it was determined that the well point dewatering concept was not feasible
to construct and would not be an effective dewatering tool.
4
4.0 CELL 2 PIEZOMETER MONITORING
Standpipe piezometers were installed across Cell 2 prior to the first phase of final cover placement
to monitor changes in water levels due to dewatering prior to and after final cover placement.
These piezometers provide information on the rate and extent of dewatering of the tailings. The
piezometers were primarily located adjacent to the settlement monuments to minimize damage to
the piezometers during cover construction, while providing sufficient locations to evaluate the
water levels.
Attachment B presents figures showing water levels in the piezometers since installation (June
2016) through January 2020. Figure B.1 shows the water levels for all the piezometers. For
comparison, Figures 8.2, 8.3 and B.4 show the water levels in the piezometers located on the west
side of Cell 2 (excluding locations near the sump), near the sump, and on the east side of Cell 2
(excluding locations near the sump), respectively. Water levels are lower near the sump, indicating
migration of water towards the sump.
The figures show that water levels for piezometers increased during the Phase 1 cover placement
(late 2016 to early 2017), and then generally decreased until the wet winter/spring of 2019. The
increase in water levels was expected during Phase 1 cover placement and is due to the excess pore
water pressure from consolidation associated with the loading from the additional cover. In 2019
water levels for piezometers increased or were generally level for the majority of the year. These
conditions are likely due to the significantly wet 2019 winter/spring. For the piezometers with
increasing water levels in 2019, recent readings are showing a return to a decreasing trend in water
levels. Overall, water levels have decreased since Phase 1 cover placement. A summary of water
level changes since Phase 1 cover placement is provided in Table 4.
5.0 CELL 2 SETTLEMENT MONITORING
Settlement monument measurements since installation through December 2019 are shown in the
graphs presented in Attachment C. Table 5 lists the settlement measured since the start of Phase
1 cover construction (April 2016) through December 2019. Settlement totals during this period
range from 0 to 0.5 feet. Settlement of the cover surface due to the Phase 1 cover loading is
occurring as expected, with a relatively quick response to the additional loading, as occurred when
the initial interim fill was placed on the tailings. The majority of total settlement due to Phase 1
cover placement is estimated to have occurred. Settlement is showing a decreasing trend and less
than 0.1 feet of cumulative settlement was measured for 2019 for all the monuments (range of 0
to 0.06 feet).
6.0 SUMMARY AND CONCLUSIONS
The purpose of this Slimes Plan is to provide data to ensure that fluid removal from the tailings
cell slimes drain is effectively dewatering the tailings to the extent practicable in order to allow
placement of final cover within specified time frames. Part I.H.1 of the GWDP provides multiple
methods to evaluate the effectiveness of tailings cell dewatering including:
5
1. Demonstration of decreasing fluid elevation trends as measured by slimes drain recovery tests;
2. Evaluations of head data from piezometers installed in the affected tailings cell demonstrating
net dewatering, and
3. Demonstration of decreasing trends in cell settlement monitoring.
Below are the results of the assessment of the three GWDP listed items.
6.1 Demonstration of Decreasing Fluid Trends in the Slimes Drain Recovery Tests
As previously stated, the Phase 1 cover activities included the placement and compaction of
approximately 4.5 feet of soil materials. These cover placement activities caused an increase in
the measured elevations of the Cell 2 slimes drain fluids. The cover materials surcharged the
tailings mass, creating excess pore pressure as the fluid was compressed along with the tailings.
As a result of the increased pore pressure, the phreatic surface of the Cell 2 slimes increased, and
the amount of fluid available for pumping increased. The increase in elevations was expected
and is unavoidable during cover construction activities.
The graphical representations of the Cell 2 slimes drain recovery test data from 2009 — 2019,
included in Attachment A, shows an overall downward trend since 2009 indicating that the
pumping is removing the Cell 2 slimes effectively and the levels are decreasing indicating positive
progress in dewatering. While an increase in the slimes drain fluid level is noted in the fourth
quarter of 2016 (which corresponds to the Phase 1 cover activities) the trend from the highest
surcharge in December 2016 is also downward with levels within 0.83 feet of the lowest measured
pre-cover level. While some minor increases are noted in the December 2016 - 2019, the overall
trend in slimes drain fluid elevations is downward. Minor upticks are likely the levels result of
increased precipitation in 2019 as noted in Section 2.0 above.
The slimes drain pump in Cell 2 is activated and deactivated by a float mechanism and water level
probe system which causes the system to pump whenever fluids are present in the system. In
addition, the slimes drain pump has been lowered to the lowest point practicable to maximize the
length of time the pump operates. The slimes drain pumping system design maximizes the time
the pump operates and therefore maximizes the dewatering. An increase in the annual volume of
fluid pumped is noted from 2016 through 2019 when compared to the pre-cover (2015) levels.
The cover placement increased the amount of fluid available for pumping and the system design
optimized the removal of the additional fluids. The increased volumes pumped, noted in Table 3,
indicates that pumping was completed effectively and at the maximum extent possible.
To maximize the pumping of the Cell 2 slimes drain, which in turn maximizes the dewatering (as
indicated by the decreasing fluid levels), EFRI monitors the operation of the pumping system daily.
EFRI has not reported a Cell 2 pumping system outage that lasted longer than 24-hours since 2013.
It is important to note that the 2013 outage was caused by sub-zero, freezing weather which froze
the discharge lines, which was outside of EFRI' s control. Continuous operations of the Cell 2
slimes has maximized the pumping and dewatering to the maximum extent possible.
6
As stated above, the Cell 2 slimes drain pumps fluid at the maximum rate possible once the fluids
flow into the slimes drain sump. The flow of liquid into the slimes drain is governed by the
relatively low permeability of the overlying tailings. There are no system designs or modifications
which can increase the volume of fluid pumped because the velocity of fluid flowing to the sump
is driven by the permeability of the tailings. No changes can be made to Cell 2 which would
increase the tailings permeability. As such EFRI is pumping and dewatering at the maximum rate
possible.
The lowest Cell 2 slimes drain recovery test measurement of 28.83 feet below the measuring point
was recorded June 21, 2016. Prior to cover placement activities and through June 2016, the pace
of dewatering had decreased and approached a "horizontal asymptote" or a leveling off. The
leveling off of the volume of fluids pumped is expected and beyond the control of EFRI for the
reasons stated above. Leveling off of the volume does not indicate that pumping is not effectively
dewatering the cell or that the maximum volume is not being pumped, it indicates that the low
permeability of the tailings is governing the rate of dewatering.
The results of the alternative dewatering tests described in Section 3.4 showed that additional
processes for dewatering have little to no effect on the dewatering rate and would not result in an
increased volume of slimes pumped. There are no other strategies or engineering modifications
available to EFRI that would provide a meaningful increase in the dewatering rate on Cell 2.
Overall, EFRI is pumping fluids and dewatering Cell 2 effectively and at the maximum rate
possible. The pumping system is optimized to provide the maximum pumping and fluid removal.
No additional system modifications are possible.
6.2 Evaluation of Piezometer Head Data to Demonstrate Net Dewatering
Since the Cell 2 Phase 1 cover was placed, the piezometers show a decreasing trend in water levels
in the tailings that demonstrates net dewatering of the tailings. Water levels were lowered by
approximately 1 to 3 feet (net) across the cell during this time period. Piezometer water levels
are lower near the sump signifying continued migration of water towards the sump due to
dew atering.
As with the Cell 2 slimes drain elevations, fluid levels for piezometers increased during the Phase
1 cover placement (late 2016 to early 2017). Piezometer levels then generally decreased until the
wet winter/spring of 2019. The increase in fluid levels was expected during Phase 1 cover
placement and is due to the excess pore water pressure from consolidation associated with the
loading from the additional cover. In 2019 fluid levels for piezometers increased or were generally
level for the majority of the year. These conditions are likely due to the significantly wet 2019
winter/spring. For the piezometers with increasing fluid levels in 2019, recent readings are
showing a return to a decreasing trend in fluid levels.
As previously stated, the pumping system is optimized to pump the maximum fluid from Cell 2
and any minor increase in fluid levels due to increased precipitation are being addressed as
evidenced by the return to a downward trend in the piezometer fluid levels. Continuous operations
of the Cell 2 slimes has maximized the pumping and dewatering to the maximum rate possible.
7
A cover test section was installed on Cell 2 with layers for both Phase 1 and Phase 2 cover. Water
balance results from monitoring the cover show the test section is performing well and despite a
very wet 2019 winter/spring, allowed less than 0.1 percent of precipitation to percolate through
the cover. These results indicate that after the Phase 2 cover is placed across Cell 2, the cover is
expected to effectively minimize precipitation from infiltrating into tailings. It is expected that a
wet precipitation season would have minimal impact on the water levels in the tailings compared
to the response seen in 2019 for Cell 2.
6.3 Demonstration of Decreasing Trends in Cell Settlement Monitoring
Cell 2 settlement monuments show a decreasing trend in settlement since the Phase 1 cover was
placed, with less than 0.1 feet of cumulative settlement occurring in 2019. The majority of
settlement due to the Cell 2 Phase 1 cover placement occurred quickly during the construction
season as expected.
6.4 Radon Mitigation
The Phase 1 cover activities included the placement of approximately 4.5 feet of cover soil. Data
from 2017 — 2018 show that the cover placed to date has successfully reduced the radon flux to
well below 20 picocuries per square meter per second (pCi/m2-sec). The 2017 and 2018 average
radon flux measurements were 0.7 and 3.35 pCi/m2-sec respectively. Preliminary 2019 results
indicate the low radon flux levels continue in 2019. The low radon flux data indicate that the
Phase 1 cover is adequate to protect human health and safety, as well as the environment until
the final cover layers are placed.
6.5 Conclusion
The Cell 2 slimes drain pumping and recovery tests, the piezometer data and the settlement
monitoring data indicate that the Cell 2 slimes pumping system is operating effectively and that
Cell 2 is being dewatered at the maximum possible rate.
8
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FIGURES
"
® 62 West <
/ ner 5598
"-----__Cover: 5615
Depth to,
-* C2 Central Liner: 5589
Cover: 5615
Depth to Liner: 26'
Energy Fuels Resources (USA) Inc.
REVISIONS Project: White Mesa Mill
Date By County: San Juan State: Utah
Location:
Figure 1
Cell 2 Dewatering
Phase 1 Well Location
SCALE IN FEET Author: RE Date: 8/1 8/1 5 Drafted By:
* C2 Central Dewatering Wells Point Table Utah South NAD83 State Plane Feet
200 400 200 100 0
•Point Raw Description Northing act no
1 C2 West 10164238 2916960
2 C2 Central 10164187 4217631
3 C2 East 10164069 2218945
1
2 0' 8" Steel Pipe
6" Slotted PVC Pipe
4' deep
Backhoe Trench
Possible Tailings
Solution Depth
8 BGS
15.0'
0.5'
f
Notes:
1. Inserting the 8" steel pipe
1.1. A 4-foot deep trench will be excavated through the cover soil and
into the tailings. This material will be placed directly into the loader
bucked and trammed to Cell 3 to avoid contamination of the cover
soil.
1.2. The steel pipe will have ears welded onto the pipe at 12 and at 20.
This will allow a chain inserted into the ears and used to pull the
pipe into the tailings sands. The loader or backhoe will be required
to pull the pipe into the tailings depending on the resistance.
1.3. Once the pipe is inserted approximately 6 feet into the tailings (10
below the top of the cover soil), backfill the trench with rocky
random fill. This will allow for a safe working area around the pipe.
1.4. Move the chain from the 12 ears to the 20' ears and continue
advancing the pipe into the tailings sands until there is about 2
remaining above the tops of the cover soil.
2. Removing the tailings sands from the 8" pipe
2.1. The tailings sands need to be removed from the 8" pipe to allow for
the 6" PVC pipe to be installed.
2.2. A Tee will need to be installed on the top of the 8" steel pipe to
allow for a controlled flush of the 8" pipe with water to remove the
tailing sands.
2.3. The top needs to extend 2 above the horizontal leg of the tee.Tthis
will allow for the solution and sand to be deposited from the
horizontal leg and into a container and for the water supply line to
be inserted in the top. The tailings sands and flushing water need
to be placed in Cell 3.
2.4. The flushing of the tailing sands may require 5,000 gallons and
may need to be accomplished in several steps. The flushing flow
needs to be approximately 50 gpm and 50 psi. A 4" flexible hose
should be lowed down the 8" pipe as the sands are removed.
2.5. When the tailings sands have been removed, measure the depth
to water for 10 minutes to determine how fast the flushing solutions
are flowing out the bottom of the pipe and into the tailings.
3. Install the 6' slotted PVC pipe
3.1. The slotted PVC Pipe will serve as the well long term well casing.
The bottom 15' need to be slotted. The slots should be as small as
available in a 6" pipe. I expect this to be 0.02" width for the slots.
3.2. Place 2 gallons of pea gravel in the bottom of the 8" steel pipe.
3.3. The bottom of the PVC pipe should have a perforated cap placed
on it prior to placing in the steel pipe.
3.4. Lower the PVC Pipe into the 8' steel pipe.
4. Remove the 8" steel pipe.
4.1. Re-attach the chain to the 20' ears and pull the pipe out of the
tailings sands.
4.2. The tailings sands will sluff against the 6" PVC pipe and should
hold it in place.
5. Purge the 6° PVC well
5.1. Either with a pump or a bailer, purge the 6" well for 15 minutes and
determine the pumping rate and draw down. Attempt to measure
the pumping rate while the well is drawn down the full depth. (close
to 20')
6. Continued pumping
6.1. Based on the pumping rate continue pumping:

6.1.1. 0-1 gpm - purge the well for 15 minutes once a day for a
week measuring well yield at full draw down.

6.1.2. 1-3 gpm - install a pump with a valve for flow control and
pump the well for 1 hours each day for a week. Monitor the
pumping rate each day.

6.1.3. Over 3 gpm - Install a pump with a valve for flow control and
pump the well for 2 hours each day for a week. Monitor the
pumping rate each day
Fe Energy Fuels Resources (USA) Inc.
REVISIONS Project: White Mesa Mill
Date By CountY: San Juan State:Utah
Location:
Figure 2
Dewatering Well Construction
Author: Date: 8/18/15 Drafted By:
TABLES
Table 1 2018-2019 Site and Lon -term Avera e Preci itation
Month
Blanding Long-
term Average
Precip.
(mm)
2018 Site
Precip.
(mm)
Percent of
Long-term
Average
Precip.
(%)
2019 Site
Precip.
(mm)
Percent of
Long-term
Average
Precip.
(%)
Jan 35.56 8.20 23% 46.72 131%
Feb 30.99 4.24 14% 65.64 212%
Mar 25.91 8.25 32% 62.24 240%
Apr 21.84 3.07 14% 12.17 56%
May 18.03 6.54 36% 36.66 203%
Jun 11.18 11.73 105% 2.26 20%
Jul 29.21 6.42 22% 4.71 16%
Aug 34.54 9.99 29% 8.69 25%
Sep 32.51 2.55 8% 0.01 0%
Oct 36.58 81.74 223% 5.20 14%
Nov 26.16 5.58 21% 21.12 81%
Dec 35.31 15.11 43% 42.52 120%
337.82 163.42 48% 307.94 91%
Table 2 Cell 2 Cover Test Section Water Balance Quantities
Calendar
Year
Water Balance Quantities (mm)
Precipitation Runoff Lateral
Flow Evapotranspiration Change in
Storage Percolation
2018 163.4 0.09 0.00 124.6 37.9 0.90
2019 309.1 0.28 0.00 325.9 3.3 1.01
Table 3 Slimes Drain Volume Pum ed 2015 - 2019
Year Gallons Pumped
2015 1,004,382
2016 1,256,906
2017 1,238,677
2018 1,145,522
2019 1,069,604
1
1
1
I
1
1
1
1
I
I
1
I
1
1
1
1
1
i
I
Table 4 Piezometer Water Level Elevations Durin and After Phase 1 Cover Placement
Piezometer
Location
on Cell
Maximum
Measured Water
Level Elevation
during Phase 1
Cover Placement
(ft)
Measured
Water Level
Elevation on
1/3/2020 (ft)
Change in Water
Level Elevation
since Phase 1 Cover
Placement (ft)*
C2-P01 West 5612.55 5611.75 -0.80
C2-P02 West 5613.30 5612.32 -0.98
C2-P03 West 5612.31 5611.43 -0.88
C2-PO4 West 5613.97 5612.88 -1.09
C2-P05 West 5608.39 5607.10 -1.29
C2-P06 West 5609.21 5608.05 -1.16
C2-P07 West 5610.08 5608.60 -1.48
C2-P08 West 5605.25 5604.08 -1.17
C2-P09 Near Sump 5602.94 5601.89 -1.05
C2-P10 Near Sump 5601.54 5600.14 -1.40
C2-P11 Near Sump 5602.38 5600.27 -2.11
C2-P12 Near Sump 5599.45 5596.13 -3.32
C2-P14 Near Sump 5603.99 5602.58 -1.41
C2-P15 Near Sump 5604.01 5602.48 -1.53
C2-P16 Near Sump 5604.37 5602.95 -1.42
C2-P13 East 5605.72 5604.75 -0.97
C2-P17 East 5607.49 5606.79 -0.70
C2-P18 East 5607.82 5606.21 -1.61
C2-P19 East 5609.09 5607.85 -1.24
C2-P20 East 5610.63 5609.63 -1.00
C2-P21 East 5612.40 5610.28 -2.12
C2-P22 East 5613.39 5610.84 -2.55
C2-P23 East 5614.24 5611.87 -2.37
*Negative number indicates a decrease in water level.
1
1
1
1
1
1
1
I
I
I
1
1
1
1
I
1
1
1
1
Settlement
Monument
April 2016 to
December 2019
Settlement
(ft)
2019
Settlement
(ft)
2W1 0.25 0.01
2W2 0.34 0.02
2W3 0.32 0.03
2W3-S 0.36 0.03
2W4-N 0.26 0.02
2W4-C 0.29 0.04
2W4-S 0.49 0.05
2W5-N 0.25 0.03
2W5-C 0.31 0.02
2W5-S 0.41 0.05
Settlement
Monument
April 2016 to
December 2019
Settlement
(ft)
2019
Settlement
(ft)
2W6-N 0.18 0.03
2W6-C 0.30 0.00
2W6-S 0.42 0.03
2W7-N -0.03 0.03
2W7-C 0.08 0.02
2W7-S 0.29 0.04
2E1-N 0.20 0.03
2E1 0.28 0.03
2E1-1S 0.31 0.03
2E1-2S 0.43 0.06
Table 5 Cell 2 Top Surface Settlement Measured Between A ril 2016 and December 2019
1
1
1
1
1
I
1
I
1
1
I
I
1
1
1
1
1
1
1
ATTACHMENT A
Cell 2 Slimes Drain Elevation Graphs
Feet Below Top of Standpipe
UJ o LEN co"' cr,`') tri cu r' NJ NJ 0 NJ NJ
a
1/30/2009
• 5/30/2009
• 9/30/2009
1/31/2010
• 5/31/2010
9/30/2010
• 1/31/2011
5/31/2011
• 9/30/2011
1/31/2012
• 5/31/2012
9/30/2012
1/31/2013
• 5/31/2013
9/30/2013
• 1/31/2014
5/31/2014
9/30/2014
1/31/2015
5/31/2015
9/30/2015
1/31/2016
5/31/2016
9/30/2016
1/31/2017
5/31/2017
9/30/2017
1/31/2018
5/31/2018
9/30/2018
1/31/2019
5/31/2019
9/30/2019

NJ

(z
sa
p
as
)

U.) NJ NJ NJ 0 VD Oa --.1 6 6 'o 6 o o 0 0
NJ NJ cri
cp
NJ NJ NJ UJ SJ

(Z
sa
p
as
) J
e
a
u
n

-

Feet Below Top of Standpipe
12/5/2016
1/5/2017
2/5/2017
3/5/2017
4/5/2017
5/5/2017
1- 6/5/2017
r 7/5/2017
k 8/5/2017
9/5/2017
10/5/2017
11/5/2017
[
12/5/2017
1/5/2018
2/5/2018
3/5/2018
4/5/2018
5/5/2018
F. 6/5/2018 1 h 7/5/2018
8/5/2018
9/5/2018
[
1_
10/5/2018
11/5/2018
12/5/2018
1/5/2019 1
F
2/5/2019
3/5/2019
4/5/2019
5/5/2019 1 1 6/5/2019
7/5/2019
8/5/2019
9/5/2019
10/5/2019
11/5/2019
ATTACHMENT B
Cell 2 Piezometer Data
Jun-17 Dec-17 Jun-18 Dec-16 Jun-20 Dec-18 Jun-19 Dec-19
Figure B.1 - Cell 2 Standpipe Piezometers
Water Level Elevations
C2-P01 • - C2 P02 C2-P03 C2-PO4 C2 P05 —X— C2-P06 —4K---
—E3— C2-P10 --,...- C2-P07 —I— C2-P08 —8— C2-P09 —0— C2-P 11 —6—C2-P12
—:X.--C2-P13 C2-P14 • C2-P15 C2-P16 —6— C2-P17 C2-P18
—*—C2-P19 —*—C2-P20 C2-P21 0 ---4---- C2-P22 —1!r—C2-P23
Note (1): Pieozometer C2-P01 reading for Mar 20, 2019
was erroneous due to an issue with the water level meter
Date
Wa
te
r Le
v
e
l
E
le
va
tio
n

(
ft
)

5,615
5,610
5,605
5,600
5,595
5,590
Jun-16
5,590
Jun-16 Jun-19 Dec-19 Jun-20 Jun-18
Date
Dec-16 Jun-17 Dec-17 Dec-18
5,615
5,610
5,605
5,600
Note (1): Pieozometer C2-P01 reading for March 20, 2019
was erroneous due to an issue with the water level meter
5,595
C2-P01 --e--C2-P02 C2-P03 C2-PO4
—A—C2-P05 —*—C2-P06 —C2-P07 —1—C2-P08
Wa
te
r L
e
ve
l Ele
va
tio
n (
ft
)

Figure 6.2 - Cell 2 Standpipe Piezometers
Water Level Elevations
West Side of Cell (excluding locations near sump)
5,610
Jun-18
Date
Dec-19 Jun-19 Jun-20 Dec-18 Dec-17 Jun-17 Dec-16
44= 5,605
o '475 ca
a)
LU
a)
Q.;
5,600
5,595
5,590
Jun-16
Figure B.3 - Cell 2 Standpipe Piezometers
Water Level Elevations
Locations Near Sump
Jun-18
Date
Jun-16 Dec-16 Jun-17 Dec-17 Dec-18 Jun-19 Dec-19 Jun-20
Figure B.4 - Cell 2 Standpipe Piezometers
Water Level Elevations
East Side of Cell (excluding locations near sump)
C2-P18 —*--C2-P19 44—C2-P13 —Ar—C2-P17
—ta—C2-P20 —8—C2-P21 C2-P22 —6—C2-P23
Wa
te
r L
e
ve
l
E
le
v
at
io
n

(
ft
)

5,615
5,610
5,605
5,600
5,595
5,590
ATTACHMENT C
Settlement Monitor Data
MI NMI MIIIIMIIIMI INIIM 11.1 MI NEM MN NM 1111111 MI
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
El
e
v
atio
n,
f
e
e
t r
n
s
l
Figure C.1
White Mesa Mill
Cell 2W1 Settlement Plate Measurements
(1)
(1)
mlorommenimmommap.---, mmmilllasihmkranimm.m.
Note: (1) Settlement plate extended during Phase 1 cov er construct ion.
El
e
v
atio
n,
f
e
et m
s
l 5624
5622
5620
Note: (1) Settlement plate exte nded during Phase 1 cov er construct ion.
MO =II NM I= MN MI =I IMO MINIMIININ MN MOM— IIMMINISM
5632
5630
5628
5626
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
Figure 0.2
White Mesa Mill
Cell 2W2 Settlement Plate Measurements
(1)1111111mumn
•
IMIN NM MI MN INN IIIN 11111—N1111 NOM MN
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
El
e
va
tio
n,
fe
e
t m
s
l

Figure C.3
White Mesa Mill
Cell 2W3 Settlement Plate Measurements
,l)glimmems
•
Note: (1 Settlement plate exten ded during Phase 1 cover construction.
:011111muum
Note: (1) Settlement plate extended durin g Phase 1 co ver construction.
El
e
v
a
ti
o
n
,

fe
e
t
m
e
i
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
NM NM MN NM MON NM N111111 MIN MOM- II= 111•111•11-
Figure 0.4
White Mesa Mill
Cell 2W4 Settlement Plate Measurements
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
NM I= MN NM MI NM MTh
Figure 0.5
White Mesa Mill
Cell 2E1 Settlement Plate Measurements
El
e
v
a
tio
n
,

fe
e
t
m
s
l
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Note: (1) .ettlement late exten
1 III 1111111,1,11'11 iiiIIIIIII•IIIIII WWII hi,ii I,
III
r , IIIIHIH llflllllll li IfjojIlln ,' .

1111
ed during hase 1 cov r construct on.
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
El
e
va
tio
n
,

fe
e
t m
s
l
a
on. Note: (1) ettlement plate extend ed during P hase 1 cove r constructi
MI NM MI MI an MI MN NM =II INII MI =I MI MN NM MI MN MN NM
Figure 0.6
White Mesa Mill
Cell 2E1-N Settlement Plate Measurements
i i
(1) solomsni
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
10101 MI MN MI =I En MN MI 11•11 MI NM MI =I =I NM MN IIIM IIIIII OM
Figure C.7
White Mesa Mill
Cell 2E1-1S Settlement Plate Measurements
5632
5630
5628 (1) Illinnamm
5626 1).
El
e
v
ati
on,
fe
e
t m
s
l 5624
5622
5620
5618
5616
5614
_
Note: (1 ) Settlemen t plate exten ded during Phase 1 co er construc tion.
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
El
e
va
tio
n
,

fe
e
t m
s
l 5624
5622
5620
MI I= MI MEM MI IMMI MN Ma =I NM NM MI ME I= MN
5632
5630
5628
5626
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
Figure 0.8
White Mesa Mill
Cell 2E1-2S Settlement Plate Measurements
(1.)rmum
us 1)
,1)
plate extended during ohase 1 cover construction. Note: 1) Settlement
El
e
v
a
tio
n,
fe
e
t
m
s
l
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
i IN11-11•11 II= INIIII—Mil 11=11•1111M NMI MIMI Mill MI ME
Figure C.9
White Mesa Mill
_Cell 2W7-C Settlement Plate Measurements
(1) ullialmollemi
Note: (1
month b
) Settlemen t plate had three feet o
ecause intei" im cover was added in
‘ rod exten ed October
this area of Cell 2
2014
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
(1)uamomme
1)U
IA 1 I H 111111I II I '111111111 111111111 OW1111101
111111111W I j 1
El
e
v
atio
n,
fe
e
t
m
s
l
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
MN NM MI INIITh MI MI MI OM NM IMO IMMI I= IIIM-1111
Figure 0.10
White Mesa Mill
,Cell 2W5-N Settlement Plate Measurements
Note: (1) Settlement plate exten ed during Phase 1 cov er construct on.
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
1)
Settlement plate extettided during Phase 1 co er construc ion. Note: (1
Figure 0.11
White Mesa Mill
,Cell 2W3-S Settlement Plate Measurements
MN MN NMI MOS Mil MN MI MI NM I= MI MI
El
e
va
tio
n
,

fe
e
t m
s
l
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
MN MOM IIMIIIINIM OM IMIIIM INIII MI NM MIN
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
El
e
va
tio
n,
fe
e
t
r
n
s
l
Figure C.12
White Mesa Mill
Cell 2W5-S Settlement Plate Measurements
- ----- __________ --------------- - a-- --------
(1) illinalmom
(1)
lir
Note: (1) Settlemen Phase 1 co ver construct ion. t plate exte nded during
5632
5630
5628
5626
El
e
va
ti
o
n,
fe
e
t m
e
i 5624
5622
5620
5618
5616
5614
5612
NM OM NM MN MI MN MN 10111 IINN/111- MOM MI
Figure 0.13
White Mesa Mill
Cell 2W7-N Settlement Plate Measurements
,
(2)
(1)
_
Notes: (1) Settlement plate had three feet of rod extend d in Octob r 2014
(2)
because interim
Settlement
cover
plate extended
was added in
during
this area If Cell 2
phase 1 covrr construc ion
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
El
e
v
ati
o
n,
fe
e
t m
s
l
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
1•11-11M— IIIIN IM11-111011 NM MN MI MN MINI-11111111
Figure 0.14
White Mesa Mill
_Cell 2W7-S Settlement Plate Measurements
(1)Iganwanua
1)111rni
Note: (1) Settlemer t plate exte nded during Phase 1 co Ver construction. 5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
NM MI -11M111- MTh Mil MN MN MN MI MIN MI NM NM
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
El
e
va
tio
n
,

fe
e
t m
s
l
Figure 0.15
White Mesa Mill
Cell 2W6-N Settlement Plate Measurements
(1)iummunima
1).
Note: (1) Settlement plate extenid ed during Phase 1 cov er construct ion.
Note: (1 ) Settlemen t plate exten ded during Phase 1 cov er construction.
Figure 0.16
White Mesa Mill
Cell 2W6-C Settlement Plate Measurements
MN NM-- MN MI 11•11—Mla NM MN INIINIMMON NIMMINININ
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
El
e
v
a
ti
o
n,
fe
e
t m
s
l
El
e
va
tio
n,
f
e
e
t m
s
l
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
INN MI MINNIIIM 111.111M— MI-- MI MN NM MN MI OM OM
Figure C.17
White Mesa Mill
Cell 2W6-S Settlement Plate
rumillesimmanik
1) 1111111 1111111M
Note: (1) Settlement plate exten ded during Phase 1 cove r construction.
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
( 1)U
1)Illumumm
Note: (1 ) Settlemen t plate exte nded during Phase 1 cov er construc tion.
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Dec-88
El
e
va
ti
o
n,
f
e
e
t m
s
l
Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
Figure 0.18
White Mesa Mill
Cell 2W5-C Settlement Plate
=I IMI MI MN San IMINI MIN UM 11111 MN NM Illin ININIM NM
Ele
va
tio
n,

f
e
e
t m
s
l
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
MIR II= MN --MI 1111111 MIN MI NM
Figure 0.19
White Mesa Mill
Cell 2W4-N Settlement Plate
1) 7111111111.1mm
Note: (1 ) Settlement plate exte nded during Phase 1 co er construc
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
tion.
MN MN MIN 11•11 NM NM MI =II MI MN MN ME OM MN MI MI IIIIIMI I= II=
5632
5630
5628
5626
5624
5622
5620
5618
5616
5614
5612
Dec-88 Dec-91 Dec-94 Dec-97 Dec-00 Dec-03 Dec-06 Dec-09 Dec-12 Dec-15 Dec-18 Dec-21
Ele
va
ti
o
n,
f
e
et m
e
i
Figure 0.20
White Mesa Mill
Cell 2W4-S Settlement Plate Measurements
....
Note: (1 ) Settlemen t plate exten ded during Phase 1 co er construc tion.
i