DRC-2011-001275 - 0901a068801f798c

DENISO
2011-001
Denison Mliies (USA) Corp.
1050 17th Street, Suite 950
Denver, CO 80265
USA
Tel; 303 628-7798
Fax: [phone]
www.denisonmines.com
January 21, 2011
VIA E-MAIL AND OVERNIGHT DELIVERY
Mr. Rusty Lundberg
Utah Department of Environmental Quality
195 North 1950 West
P.O. Box 144850
Salt Lake City, UT 84114-4850
Re: State.of Utah Groundwater Discharge Permit ("GWDP") No. UGW370004
Transmittal of Revised Documents Addressing White Mesa Uranium Mill New Cell 4B and Response
to Division of Radiation Control ("DRC") Draft Letter of January 21, 2011 Regarding Comprehensive
Comments on Proposed Revised Plans
Dear Mr Lundberg:
This letter transmits Denison Mines (USA) Corp's proposed revisions to the Tailings Management System
Best Available Technology Operations and Maintenance ("BAT O&M") Plan for the White Mesa Mill which is
currently pending DRC approval. This letter also responds to DRC's draft letter of January 21, 2011
requesting additional changes to previously submitted versions of this document Per DRC's letter, we
understand that the Contingency Plan will be addressed separately and changes will not be tied to approva^
for use of Cell 4B or the New Decontamination Pad.
Dension received DRC's October 11, 2010 letter requesting changes to previously submitted versions of the
DMT Plan BAT O&M Plan, and Contingency Plan. To address those comments and other changes
necessary for operation of Cell 4B, Denison submitted on November 12, 2010 redline and clean copy
revisions of those documents, entitled DMT Plan Revision 11, BAT O&M Plan Revision 2.0 and Contingency
Plan Revision 4.0. DRC reviewed those submittals and requested additional changes to the DMT and BAT
O&M Plans in a letter of January 6, 2011. Denison accepted all the changes submitted on November 12!
2010 to create new black-line copies of the DMT and BAT O&M Plans, and prepared the additional changes!
in response to DRC's January 6, 2011 letter, as redlined markups, entitled DMT Plan 11.1 and BAT O&M
Plan Revision 2.1, submitted on January 10, 2011. DRC provided contingent approval of the DMT Plan
Revision 11.1, and provided three additional comments on the BAT O&M Plan Revision 2.1 in a draft letter to
Denison dated January 21, 2011.
In response to the DRC draft letter of January 21, 2011, Denison has accepted all the changes that
constituted BAT O&M Plan Revision 2.1 and prepared a redline version addressing the: remaining three
changes to the BAT O&M Plan, which is now entitled BAT O&M Plan Revision 2.2: This revision has been
provided as Attachment 1 to this letter.
For ease of review, the revised BAT O&M Plan Revision 2:2 has also been provided as a clean black-line file
version with all changes accepted. Denison requests that UDEQ review and approve the version attached to
N:\Cell 4B\January 21 Submittals and revisions BAT O&M\01.21.11 Transmittal to DRC Plan Revisions for Cell 4B.doc
Letter to Mr. Rusty Lundberg
January 21, 2011
Page 2
this letter, which has addressed all changes submitted by Denison since September 2008, for which Denison
is awaiting DRC approval.
We have also provided, below, specific responses to each request in UDEQ's January 21, 2011 draft letter
The sections and numbering ofthe remainder of this letter follow the DRC January 21, 2011 draft letter. Eacti
UDEQ request is shown in italics, below, followed by Denison's response.
DEQ Comments and Responses
/. On page 14, there is a proposed redlined phrase in the sentence beginning with, "Each pump is
equipped with a pressure sensing transducer...," in redline it states, "for Cell 4A and 3 inches for Cell
4B)." The "3 inches" must be changed to "2-1/4 inches (0.19 feet)," or other acceptable measurement.
Denison Response: The change has been made as requested.
2. We earlier provided this request as comment VII of our January 6, 2011 letter, regarding freeboard
calculations. DUSA has chosen to propose this O&M Plan, as if Cell 4B was approved for use.
a. Therefore, the section beginning on page 15, titled "Cell 4A Solution Freeboard Calculation," needs
to be re-titled to "Solution Freeboard Calculations," (as this section provides freeboard calculations
for Cell 1 and 4B) or another acceptable title.
Denison Response; The change has been made as requested.
b. The last sentence of this section, on page 17 needs to delete the reference to Cell 4A.
Denison Response: The change has been made as requested.
3. On page 5, paragraph d.2, there is a proposed redline change. The 18-inch diameter (proposed to be
deleted) is correct in accordance with the CQA Report record drawings; and must be retained. The
redline change proposed, i.e. a 2-foot inside diameter pipe is incorrect, and should be removed.
Denison Response: The change has been made as requested.
Please contact the undersigned if you have any questions or require any further information:
Yours very truly.
DENISON MINES (USA) CORP.
Jo Ann Tischler
Director, Compliance and Permitting
cc: David C. Frydenlund
Harold R. Roberts
David E. Turk
K. Weinel
Central files
DENISO
MINES
ATTACHMENT 1
PROPOSED REVISON 2.270 BAT OPEMTIONS AND MANAGEMENT PLAN
RED-LINED AND CLEAN VERSIONS
0l /n!2011 Revision Denison 2.42
Cell 4A and 48 BAT Monitoring, Operations and Maintenance Plan.
Introduction
Construction of Cell4A was authorized by the Utah Departrnent of Environmental
Quality, Division of Radiation Control ("DRC) on June 25,2007. The construction
authorization provided that Cell4A shall not be in operation until after a BAT
Monitoring, Operations and Maintenance Plan is submitted for Executive Secretary
review and approval. The Plan shall include requirements in Part I.F.3 of the
Groundwater Discharge PermitNo. UGW370004 ("GWDP") and fulfrll the
requirements of Parts I.D.6, I.E.8, and I.F.9 of the GWDP.
Construction of Cell48 was authorized by DRC on June 21,2010. The construction
authorization provided that Cell48 shall not be in operation until after a BAT
Monitoring, Operations and Maintenance Plan is submitted for Executive Secretary
review and approval. The Plan shall include requirements in Part I.F.3 of the GWDP and
fulfill the requirements of Pans l.D.l2,I.E.I2, and I.F.9 of the GWDP
Cell Desien
Tailings Cell4A consists of the following major elements:
a) Dikes - consisting of earthen embankments of compacted soil, constructed
between 1989-1990, and composed of four dikes, each including a l5-foot
wide road at the top (minimum). On the north, east, and south margins these
dikes have slopes of 3H to lV. The west dike has an interior slope of 2H to
lV. Width of these dikes varies; each has a minimum crest width of at least
15 feet to support an access road. Base width also varies from 89-feet on the
east dike (with no exterior embankment), to 2ll-feet at the west dike.
b) Foundation - including subgrade soils over bedrock materials. Foundation
preparation included excavation and removal of contaminated soils,
compaction of imported soils to a maximum dry density of 90%o. Floor of
Cell 44 has an average slope of lYo that grades from the northeast to the
southwest corners.
c) Tailings Capacity - the floor and inside slopes of Cell 44 encompass about 40
acres and have a maximum capacity of about 1.6 million cubic yards of
tailings material storage (as measured below the required 3-foot freeboard).
d) Liner and Leak Detection Systems - including the following layers, in
descending order:
l) Primary Flexible Membrane Liner (FML) - consisting of impermeable 60
N:\Cell 4BUanuarv 2l Submittals and revisions BAT O&NACell 4A and 4B O M Plan Rev 2.2 redline.docN+\Ge$
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mil high density polyethylene (HDPE) membrane that extends across both
the entire cell floor and the inside side-slopes, and is anchored in a fiench
at the top of the dikes on all four sides. The primary FML will be in direct
physical contact with the tailings material over most of the Cell 44 floor
area. In other locations, the primary FML will be in contact with the
slimes drain collection system (discussed below).
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2) Leak Detection System - includes a penneable HDPE geonet fabric that
extends across the entire area under the primary FML in Cell 44, and
drains to a leak detection sump in the southwest corner. Access to the leak
detection sump is via an l8-inch inside diameter (ID) PVC pipe placed
down the inside slope, located between the primary and secondary FML
liners. At its base this pipe will be surrounded with a gtavel filter set in
the leak detection sump, having dimensions of 10 feet by 10 feet by 2 feet
deep. In turn, the gravel filter layer will be enclosed in an envelope of
geotextile fabric. The purpose of both the gravel and geotextile fabric is to
serve as a filter.
3) Secondary FML - consisting of an impermeable 60-mil HDPE membrane
found immediately below the leak detection geonet. Said FML also
extends across the entire Cell 44. floor, up the inside side-slopes and is
also anchored in a trench at the top of all four dikes.
4) Geosynthetic Clay Liner - consisting of a manufactured geosynthetic clay
liner (GCL) composed of 0.2-inch of low permeability bentonite clay
centered and stitched between two layers of geotextile. Prior to disposal
of any wastewater in Cell 44, the Permittee shall demonstrate that the
GCL has achieved a moisture content of at least 50% by weight. This
item is a revised requirement per DRC letter to DUSA dated Sepember
28,2007
e) Slimes Drain Collection System - including a two-part system of strip drains
and perforated collection pipes both installed immediately above the primary
FML, as follows:
1) Horizontal Strip Drain System - is installed in a heningbone pattern
across the floor of Cell 44 that drain to a "backbone" of perforated
collection pipes. These strip drains are made of a prefabricated two-part
geo-composite drain material (solid polymer drainage strip) core
surrounded by an envelope of non-woven geotextile filter fabric. The strip
drains are placed immediately over the primary FML on 50-foot centers,
where they conduct fluids downgradient in a southwesterly direction to a
physical and hydraulic connection to the perforated slimes drain collection
pipe. A series of continuous sand bags, filled with filter sand cover the
strip drains. The sand bags are composed of a woven polyester fabric
filled with well graded filter sand to protect the drainage system from
plugging.
2) Horizontal Slimes Drain Collection Pipe System - includes a "backbone"
piping system of 4-inch ID Schedule 40 perforated PVC slimes drain
collection (SDC) pipe found at the downgradient end of the strip drain
lines. This pipe is in tum overlain by a berm of gravel that runs the entire
diagonal length of the cell, surrounded by a geotextile fabric cushion in
immediate contact with the primary FML. The non-woven geotextile
material is overlain at the surface by a woven geotextile fabric, which is
N:\Cell 4BUanuarv 2l Submittals and revisions BAT O&NACell 4,A, and 48 O M Plan Rev 2.2 redline.docN:€ell
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ballasted laterally by sandbags on each side of the backbone of the berm.
In furn, the gravel is overlain by a layer of non-woven geotextile to serve
as an additional filter material. This perforated collection pipe serves as
the "backbone" to the slimes drain system and runs from the far northeast
corner downhill to the far southwest corner of Cell 4,{ where it joins the
slimes drain access pipe.
3) Slimes Drain Access Pipe - consisting of an l8-inch ID Schedule 40 PVC
pipe placed down the inside slope of Cell 44 at the southwest corner,
above the primary FML. Said pipe then merges with another horizontal
pipe of equivalent diameter and material, where it is enveloped by gravel
and nonwoven geotextile that serves as a cushion to protect the primary
FML. The non-woven geotextile material is overlain at the surface by a
woven geotextile fabric, which is ballasted by sandbags.A reducer
connects the horizontal l8-inch pipe with the 4-inch SDC pipe. At some
future time, a pump will be set in this l8-inch pipe and used to remove
tailings wastewaters for purposes of de-watering the tailings cell.
Dike Splash Pads - A minimum of eight (S) 20-foot wide splash pads are
installed on the interior dike slopes to protect the primary FML from abrasion
and scouring by tailings slurry. These pads consist of an extra layer of 60 mil
HDPE membrane that is placed down the inside slope of Cell44, from the top
of the dike and down the inside slope. The pads extend to a point 5-feet
beyond the toe of the slope to protect the liner bottom during initial startup of
the Cell. The exact location of the splash pads is detailed on the As-Built
Plans and Specifications.
Rub Protection Sheets - In addition to the splash pads described in f) above,
rub sheets are installed beneath all piping entering or exiting Cell 4,{ that is
not located directly on the splash pads.
Emergency Spillway - a concrete lined spillway constructed near the westem
corner of the north dike to allow emergency runoff from Cell 3 into Cell 44.
This spillway will be limited to a 6-inch reinforced concrete slab set directly
over the primary FML in a 4-foot deep trapezoidal channel. A second
spillway has been constructed in the southwest comer of Cell 44 to allow
emergency runoff from Cell 44 into Cell 48. All stormwater runoff and
tailings wastewaters not retained in Cells 3 and 4A, will be managed and
contained in Cell 48, including the Probable Maximum Precipitation and
flood event.
Tailings Cell48 consists of the following major elements:
a) Dike - consisting of a newly-constructed dike on the south side of the cell
with a l5-foot wide road at the top (minimum) to support an access road.
The grading plan for the Cell 48 excavation includes interior slopes of 2H
to lV. The exterior slope of the southern dike will have the typical slopes
of 3H to lV. Limited portions of the Cell 48 interior sideslopes in the
northwest comer and southeast corner of the cell (where the slimes drain
N:\Cell 4BUanuary 2l Submittals and revisions BAT O&lvl\Cell 4,4' and 48 O M Plan Rev 2.2 redline.docN:\Cell
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Cell 4A BAT Monitoring, Operations and Maintenance Plan 9l+l&l:2010 Revision
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and leak detection sump will be located) will also have a slope of 3H to
lV. The base width of the southern dike varies from approximately 100
feet at the western end to approximately 190 feet at the eastern end of the
dike, with no exterior embankment present on any other side of the cell.
Foundation - including subgrade soils over bedrock materials. Foundation
preparation included 6-inch over excavation of rock and placement and
compaction of imported soils to a maximum dry density of 90Yo at a
moisture content between +3Yo and -3Yo of optimum moisfure content, as
determined by ASTM D-I557. The floor of Cell 48 has an average slope
of lYo that grades from the northwest corner to the southeast comer.
Tailings Capacity - the floor and inside slopes of Cell 48 encompass
about 45 acres and the cell will have a water surface area of 40 acres and a
maximum capacity of about 1.9 million cubic yards of tailings material
storage (as measured below the required 3-foot freeboard).
Liner and Leak Detection Systems - including the following layers, in
descending order:
Primary Flexible Membrane Liner (FML) - consisting of 60 mil high
density polyethylene (HDPE) membrane that extends across both the
entire cell floor and the inside side-slopes, and is anchored in a trench at
the top of the dikes on all four sides. The primary FML will be in direct
physical contact with the tailings material over most of the Cell 48 floor
area. In other locations, the primary FML will be in contact with the
slimes drain collection system (discussed below).
Leak Detection System - includes a penneable HDPE geonet fabric that
extends across the entire area under the primary FML in Cell 48, and
drains to a leak detection sump in the southeast corner. Access to the leak
detection sump is via an 2$et!8-itgh inside diameter (ID) PVC pipe
placed down the inside slope, located between the primary and secondary
FML liners. At its base this pipe will be surrounded with a gravel filter set
in the leak detection sump, having dimensions of 10 feet by 10 feet by 2
feet deep. In tum, the gravel filter layer will be enclosed in an envelope of
geotextile fabric. The purpose of both the gravel and geotextile fabric is to
serve as a filter.
3) Secondary FML - consisting of a 60-mil HDPE membrane found
immediately below the leak detection geonet. Said FML also extends
across the entire Cell 48 floor, up the inside side-slopes and is also
anchored in a trench at the top of all fotr dikes.
4) Geosynthetic Clay Liner - consisting of a manufactured geosynthetic clay
liner (GCL) composed of 0.2-inch of low permeability bentonite clay
centered and stitched between two layers of geotextile. Prior to disposal
of any wastewater in Cell 48, the Permittee shall demonstrate that the
GCL has achieved a moisture content of at least 50%by weight.
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b)
c)
d)
l)
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Cell 4A BAT Monitoring, Operations and Maintenance Plan U+lAI20l0 Revision
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Slimes Drain Collection System - including a two-part system of strip
drains and perforated collection pipes both installed immediately above
the primary FML, as follows:
Horizontal Strip Drain System - is installed in a herringbone pattern
across the floor of Cell 48 that drain to a "backbone" of perforated
collection pipes. These strip drains are made of a prefabricated two-part
geo-composite drain material (solid polymer drainage strip) core
surrounded by an envelope of non-woven geotextile filter fabric. The strip
drains are placed immediately over the primary FML on S0-foot centers,
where they conduct fluids downgradient in a southeasterly direction to a
physical and hydraulic connection to the perforated slimes drain collection
pipe. A series of continuous sand bags, filled with filter sand cover the
strip drains. The sand bags are composed of a woven polyester fabric
filled with well graded filter sand to protect the drainage system from
plugging.
Horizontal Slimes Drain Collection Pipe System - includes a "backbone"
piping system of 4-inch ID Schedule 40 perforated PVC slimes drain
collection (SDC) pipe found at the downgradient end of the strip drain
lines. This pipe is in tum overlain by a berm of gravel that runs the entire
diagonal length of the cell, surrounded by a geotextile fabric cushion in
immediate contact with the primary FML. In turn, the gravel is overlain
by a layer of non-woven geotextile to serve as an additional filter material.
The non-woven geotextile material is overlain at the surface by a woven
geotextile fabric, which is ballasted by sandbags. This perforated
collection pipe serves as the o'backbone" to the slimes drain system and
runs from the far northwest corner downhitl to the far southeast corner of
Cell48 where it joins the slimes drain access pipe.
Slimes Drain Access Pipe - consisting of an l8-inch ID Schedule 40 PVC
pipe placed down the inside slope of Cell 48 at the southeast comer,
above the primary FML. Said pipe then merges with another horizontal
pipe of equivalent diameter and material, where it is enveloped by gravel
and non-woven geotextile that serves as a cushion to protect the primary
FML. The non-woven geotextile material is overlain at the surface by a
woven geotextile fabric, which is ballasted laterally by sandbags on each
side of the backbone of the berm. A reducer connects the horizontal 18-
inch pipe with the 4-inch SDC pipe. At some future time, a pump will be
set in this l8-inch pipe and used to remove tailings wastewaters for
purposes of de-watering the tailings cell.
Cell 48 North and East Dike Splash Pads - Nine 20-foot-wide splash pads
will be constructed on the north and east dikes to protect the primary FML
from abrasion and scouring by tailings slurry. These pads will consist of
an extra layer of textured, 60 mil HDPE membrane that will be installed in
the anchor trench and placed down the inside slope of Cell 48, from the
top of the dike, under the inlet pipe, and down the inside slope to a point at
N:\Cell 4BVanuary 2l Submittals and revisions BAT O&tv{\Cell 44, and 48 O M Plan Rev 2.2 redline'docN'.\Gell
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Cell 4A BAT Monitoring, Operations and Maintenance Plan UUA[2010 Revision
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least 5 feet onto the Cell48 floor beyond the toe of the slope.
g) Rub Protection Sheets - In addition to the splash pads described in f)
above, rub sheets are installed beneath all piping entering or exiting Cell
48 that is not located directly on the splash pads'
h) Emergency Spillway - a concrete lined spillway constructed near the
southern corner of the east dike to allow emergency runoff from Cell 4A
into Cell 48. This spillway will be limited to a 6-inch reinforced concrete
slab, with a welded-wire fabric installed within its midsection, set atop a
cushion geotextile placed directly over the primary FML in a 4-foot deep
trapezoidal channel. A 100 foot wide, 60 mil HDPE geomembrane splash
pad will be installed beneath the emergency spillway. No other spillway
or overflow structure will be constructed at Cell 48. All stormwater
runoff and tailings wastewaters not retained in Cells 2,3 and 4A, will be
managed and contained in Cell 48, including the Probable Maximum
Precipitation and flood event.
Cell Operation
Solution Discharge to Cell44'
Cell 44 will initially be used for storage and evaporation of process solutions
from the Mill operations. These process solutions will be from the
uranium/vanadium solvent extraction circuit, or transferred from Cell I
evaporation pond or the free water surface from Cell 3, or transferred from Cell2
tailings dewatering operations. The solution will be pumped to Cell4,{ through 6
inch or 8 inch diameter HDPE pipelines. The initial solution discharge will be in
the southwest corner of the Cell. The solution will be discharged in the bottom
of the Cell, away from any sand bags or other installation on the top of the FML.
Building the solution pool from the low end of the Cell will allow the solution
pool to gradually rise around the slimes drain sl.rips, elirninating zury darnage to
the strip drains or the sand bag cover due to solution flowing past the drainage
strips. The solution will eventually be discharged along the dike between Cell 3
and Cell 44, utilizing the Splash Pads described above. The subsequent discharge
of process solutions will be near the floor of the pond, through a discharge header
designed to discharge through multiple points, thereby reducing the potential to
damage the Splash Pads or the Slimes Drain system. At no time, subsequent to
initial filling, will the solution be discharged into less than 2 feet of solution. As
the cell begins to fill with solution the discharge point will be pulled back up the
Splash Pad and allowed to continue discharging at or near the solution level.
Solution Discharge to Cell48
Cell 48 will initially be used for storage and evaporation of process solutions
from the Mill operations. These process solutions will be from the
uranium/vanadium solvent extraction circuit, or transferred from Cell I
evaporation pond or the free water surface from Cell 3 or Cell 4A, or transferred
N:\Cell 4BUanuarv 2l Submittals and revisions BAT O&lriACell 4A' and 4B O M Plan Rev 2.2 redline.doc}*\Gell
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from Cell 2 dewatering operations. The solution will be pumped to Cell 48
through 6 inch or 8 inch diameter HDPE pipelines. The initial solution discharge
will be in the southeast corner of the Cell. The discharge pipe will be routed
down the Splash Pad provided in the southeast corner of the Cell at the spillway
to protect the primary FML. The solution will be discharged in the bottom of the
Cell, away from any sand bags or other installation on the top of the FML.
Building the solution pool from the low end of the Cell will allow the solution
pool to gradually rise around the slimes drain strips, eliminating any damage to
the strip drains or the sand bag cover due to solution flowing past the drainage
strips. The solution will eventually be discharged along the dike between Cell 3
and Cell 48, utilizing the Splash Pads described above. The subsequent discharge
of process solutions will be near the floor of the pond, through a discharge header
designed to discharge through multiple points, thereby reducing the potential to
damage the Splash Pads or the Slimes Drain system. At no time, subsequent to
initial filling, will the solution be discharged into less than 2 feet of solution. As
the cell begins to fill with solution the discharge point will be pulled back up the
Splash Pad and allowed to continue discharging at or near the solution level.
Initial Solids Discharge into Cell4A
Once Cell 44 is needed for storage for tailings solids the slurry discharge from
No. 8 CCD thickener will be pumped to the cell through 6 inch or 8 inch diameter
HDPE pipelines. The pipelines will be routed along the dike between Cell 3 and
Cell 44, with discharge valves and drop pipes extending down the Splash Pads to
the solution level. One or all of the discharge points can be used depending on
operational considerations. Solids will settle into a cone, or mound, of material
under the solution level, with the courser fraction settling out closer to the
discharge point. The initial discharge locations are shown on Figure lA. Figure
24 illustrates the general location of the solution and slurry discharge pipelines
and control valve locations. The valves are 6" or 8" stainless steel knife-gate
valves. The initial discharge of slurry will be at or near the toe of the Cell slope
and then gradually moved up the slope, continuing to discharge at or near the
water surface. This is illustrated in Section A-A on Figure 2A. Because of the
depth of Cell 4A, each of the discharge points will be utilized for an extended
period of time before the cone of material is above the maximum level of the
solution. The discharge location will then be moved further to the interior of the
cell allowing for additional volume of solids to be placed under the solution level'
The solution level in the cell will vary depending on the operating schedule of the
Mill and the seasonal evaporation rates. The tailings slurry will not be allowed to
discharge directly on to the Splash Pads, in order to further protect the FML. The
tailings slurry will discharge directly in to the solution contained in the Cell, onto
an additional protective sheet, or on to previously deposited tailings sand.
Initial Solids Discharge into Cell4B
N:\Cell 4BVanuary 2l Submittals and revisions BAT O&lvflCell 4A and 4B O M Plan Rev 2.2 redline.docN''€ell
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Once Cell 48 is needed for storage for tailings solids the sluny discharge from
No. 8 CCD thickener will be pumped to the cell through 6 inch or 8 inch diameter
HDPE pipelines. The pipelines will be routed along the dike between Cell 3 and
Cell 48, with discharge valves and drop pipes extending down the Splash Pads to
the solution level. One or all of the discharge points can be used depending on
operational considerations. Solids will settle into a cone, or mound, of material
under the solution level, with the courser fraction settling out closer to the
discharge point. The initial discharge locations are shown on Figure 18. Figure
28 illustrates the general location of the solution and slurry discharge pipelines
and control valve locations. The valves are 6" or 8" stainless steel knife-gate
valves. The initial discharge of sluny will be at or near the toe of the Cell slope
and then gradually moved up the slope, continuing to discharge at or near the
water surface. This is illustrated in Section A-A on Figure 2B. Because of the
depth of Cell 48, each of the discharge points will be utilized for an extended
period of time before the cone of material is above the maximum level of the
solution. The discharge location will then be moved further to the interior of the
cell allowing for additional volume of solids to be placed under the solution level.
The solution level in the cell will vary depending on the operating schedule of the
Mill and the seasonal evaporation rates. The tailings sluny will not be allowed to
discharge directly on to the Splash Pads, in order to ftrther protect the FML. The
tailings slurry witl discharge directly in to the solution contained in the Cell, onto
an additional protective sheet, or on to previously deposited tailings sand.
Equipment Access to Cell44' and Cell48
Access will be restricted to the interior portion of the cells due to the potential to
damage the flexible membrane liners. Only low pressure rubber tired all terrain
vehicles or foot traffic will be allowed on the flexible membrane liners. Personnel
are also cautioned on the potential damage to the flexible membrane liners
through the use and handling of hand tools and maintenance materials.
Reclaim Water System at Cell44'
A pump barge and solution recovery system is operating in the southwest corner
of the cell to pump solution from the cell for water balance pulposes or for re-use
in the Mill process. Figure 34 illustrates the routing of the solution return
pipeline and the location of the pump barge. The pump barge will be constructed
and maintained to ensure that the flexible membrane liner is not damaged during
the initial filling of the cell or subsequent operation and maintenance activities.
The condition of the pump barge and access walkway will be noted during the
weekly Cell inspections.
Reclaim Water System at Cell48
A pump barge and solution recovery system will be installed in the southeast
N:\Cell 4BUanuary 2l Submittals and revisions BAT O&lvflCell 44, and 48 O M Plan Rev 2.2 redline.docNi\ee[
lBUanuary?0ll SuhniealsandRsvisiensforGell 1B\e&MPlan0l'10,1l\€eil lAsnd lBe MlhnRev2,l
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Cell 4A BAT Monitoring, Operations and Maintenance Plan 9l+1lt2010 Revision
Denison2.2*
corner of the cell to pump solution from the cell for water balance purposes or for
re-use in the Mill process. Figure 38 illustrates the routing of the solution return
pipeline and the location of the pump barge. The pump barge will be constructed
*d maintained to ensure that the flexible membrane liner is not damaged during
the initial filling of the cell or subsequent operation and maintenance activities.
The condition of the pump barge and access walkway will be noted dtring the
weekly Cell inspections.
Interim Solids Discharge to Cell4A
Figure 44 illustrates the progression of the slurry discharge points around the
north and east sides of Cell 44. Once the tailings solids have been deposited
along the north and east sides of the Cell, the discharges points will subsequently
be moved to the sand beaches, which will eliminate any potential for damage to
the liner system.
Interim Solids Discharge to Cell48
Figure 48 illustrates the progression of the slurry discharge points around the
north and east sides of Cell 48. Once the tailings solids have been deposited
along the north and east sides of the Cell, the discharges points will subsequently
be moved to the sand beaches, which will eliminate any potential for damage to
the liner system.
Liner Maintenance and OA/OC for Cell4,{
Any construction defects or operational damage discovered during observation of
the flexible membrane liner will be repaired, tested and documented according to
the procedures detailed in the approved Revised Construction Quality
Assurancc Plan for the Construction of the Cell 4A. Lining System, May
2007, by GeoSyntec Consultants.
Liner Maintenance and OA/OC for Cell48
Any construction defects or operational damage discovered during observation of
the flexible membrane liner will be repaired, tested and documented according to
the procedures detailed in the approved Construction Quality Assurance Plan
for the Construction of the Cell 48 Lining System, October 2009' by
Geosyntec Consultants.
BAT Performance Standards for Tailines CeIl4A and 4B
DUSA will operate and maintain Tailings Cell 4A and 48 so as to prevent release of
N:\Cell 4BUanuary 2l Submiuals and revisions BAT O&llACell 44 and 48 O M Plan Rev 2.2 redline.docN:\€ell
igUaruaryigtt SubmittalsandttevisiensferGell lB€&MPlan0l,lO'trl\Gell ll\arC lBe MFlanRsv2'l
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Cell 4,{ BAT Monitoring, Operations and Maintenance Plan U+lA[2010 Revision
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wastewater to groundwater and the environment in accordance with this BAT Monitoring
Operations and Maintenance Plan, pursuant to Part I.H.8 of the GWDP. These
performance standards shall include :
1) Leak Detection System Pumping and Monitoring Equipment - the
leak detection system pumping and monitoring equipment in each cell
includes a submersible pump, pump controller, water level indicator (head
monitoring), and flow meter with volume totalizer. The pump controller
is set to maintain the ma:<imum level in the leak detection system in each
cell at no more than I foot above the lowest level of the secondary flexible
membrane, not including the sump. A second leak detection pump with
pressure transducer, flow meter, ild manufacturer recommended spare
parts for the pump controller and water level data collector is maintained
in the Mill warehouse to ensure that the pump and controller can be
replaced and operational within 24 hours of detection of a failure of the
pumping system. The root cause of the equipment failure will be
documented in a report to Mill management with recommendations for
prevention of a re-occuffence.
2) Maximum Allowable Head - the Permittee shall measure the fluid head
above the lowest point on the secondary flexible membrane in each cell
by the use of procedures and equipment specified in the White Mesa
Mill Tailings Management System and Discharge Minimization
Technolory @MT) Monitoring Plan, 10/10 Revision: Denison-10.2'
or the currently approved DMT Plan. Under no circumstance shall fluid
head in the leak detection system sump exceed a l-foot level above the
lowest point in the lower flexible membrane liner, not including the
sump.
3) Maximum Allowable Daily LDS Flow Rates - the Permittee shall
measure the volume of all fluids pumped from each LDS on a weekly
basis, and use that information to calculate an average volume pumped
per day. Under no circumstances shall the daily LDS flow volume
exceed 24,160 gallons/day for Cell 4A or 26,145 gallons/day for Cell
48. The manimum daily LDS flow volume will be compared against the
measured cell solution levels detailed on the attached Table 1A or lB for
Cells 4A or 48, respectively, to determine the maximum daily allowable
LDS flow volume for varying head conditions in the cell.
4) 3-foot Minimum Vertical Freeboard Criteria ' the Permittee shall
operate and maintain wastewater levels to provide a 3-foot Minimum of
vertical freeboard in Tailings Cell4A and Cell48. Said measurements
shall be made to the nearest 0.1 foot.
5) Slimes Drain Recovery Head Monitoring - immediately after the
Permittee initiates pumping conditions in the Tailings Cell 4A or Cell
N:\Cell 4BUanuar'.v 21 Submittals and revisions BAT O&Ivl\Cell 4,4, and 48 O M Plan Rev 2'2 redline'docN:\Gell
lBUanuary?0ll SubmittdsanCRevisiensfer€ell lB\e&MPlan0l,l0'1l\Gell 4ltend lBe MlhnRev2,l
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Page 1 1
Cell 44 BAT Monitoring, Operations and Maintenance Plan gl+lU[2010 Revision
Denison2.2*
48 slimes drain system, monthly recovery head tests and fluid level
measurements will be made in accordance with aplan approved by the
DRC Executive Secretary. The slimes drain system pumping and
monitoring equipment, includes a submersible pump, pump controller,
water level indicator (head monitoring), and flow meter with volume
totalizer.
Routine Maintenance and Monitorins
Trained personnel inspect the White Mesa tailings system on a once per day basis. Any
abnormal occurrences or changes in the system will be immediately reported to Mill
management and maintenance personnel. The inspectors are trained to look for events
involving the routine placement of tailings material as well as events that could affect the
integrity of the tailings cell dikes or lining systems. The daily inspection reports are
summarized on a monthly basis and reviewed and signed by the Mill Manager.
Solution Elevation
Measurements of solution elevation in Cell44' and Cell48 are to be taken by
survey on a weekly basis, and measurements of the beach area in Cell4.{ and Cell
48 with the highest elevation are to be taken by survey on a monthly basis, by the
use of the procedures and equipment specified in the latest approved edition of the
DMT Plan.
Leak Detection Svstem
The Leak Detection System in Cell 44 and Cell 48 is monitored on a
continuous basis by use of a pressure transducer that feeds water level
information to an electronic data collector. The water levels are measured
every hour and the information is stored for later retrieval. The water
levels are measured to the nearest 0.10 inch. The data collector is
currently programmed to store 7 days of water level information. The
number of days of stored data can be increased beyond 7 days if needed.
The water level data is downloaded to a laptop computer on a weekly
basis and incorporated into the Mill's environmental monitoring data base,
and into the files for weekly inspection reports of the tailings cell leak
detection systems. Within 24 hours after collection of the weekly water
level data, the information will be evaluated to ensure that: 1) the water
level in the Cell 44 and Cell 48 leak detection sumps did not exceed the
allowable level (5556.14 feet amsl in the Cell 4A LDS sump and 5558.5
feet amsl in the Cell 48 sump), and2) the average daily flow rate from the
LDS did not exceed the morimum daily allowable flow rate at any time
during the reporting period. For Cell 4A and Cell 48, under no
N:\Cell 4BUanuary 2l Submittals and revisions BAT O&tv{\Cell 44, and 48 O M Plan Rev 2.2 redline.docNi\Gsll
liUanuary joit Subrn:tdsendRevisi,ensferGelt lB\e&MPlan0l,l0,ll\Gell I'tand lBe MPhnRev2.l
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Cell 4A BAT Monitoring, Operations and Maintenance Plan U+lA[2010 Revision
Denison2.2*
circumstance shall fluid head in the leak detection system sump exceed a
l-foot level above the lowest point in the lower flexible membrane liner,
not including the sump. To determine the Maximum Allowable Daily
LDS Flow Rates in the Cell 4A and Cell 48 leak detection system, the
total volume of all fluids pumped from the LDS of each cell on a weekly
basis shall be recovered from the data collector, and that information will
be used to calculate an average volume pumped per day for each cell.
Under no circumstances shall the daily LDS flow volume exceed 24,160
gallons/day from Cell 44 or 26,145 gallons/day from Cell 48. The
maximum daily LDS flow volume will be compared against the measured
cell solution levels detailed on the attached Tables lA and lB, to
determine the maximum daily allowable LDS flow volume for varying
head conditions in Cell 44 and Cell 48. Any abnormal or out of
compliance water levels must be immediately reported to Mill
management. The data collector on each cell is also equipped with an
audible alarm that sounds if the water level in the leak detection sump
exceeds the allowable level (5556.14 feet amsl in the Cell 4A LDS sump
and 5558.5 feet amsl in the Cell 48 sump). The current water level is
displayed at all times on each data collector and available for recording on
the daily inspection form. Each leak detection system is also equipped
with a leak detection pump, EPS Model # 25505-3 stainless steel, or
equal. Each pump is capable of pumping in excess of 25 gallons per
minute at atotal dynamic head of 50 feet. Each pump has a 1.5 inch
diameter discharge, and operates on 460 volt 3 phase power. Each pump
is equipped with a pressure sensing transducer to start the pump once the
level of solution in the leak detection sump is approximately 2.25 feet
(elevation 5555.89 in the Cell 44 LDS sump and 5557.69 feet amsl in the
Cell48 sump) above the lowest level of the leak detection sump (9 inches
[0.75 feetl above the lowest point on the lower flexible membrane liner for
cell44 andLl/E inches [0.19 feet] for cell4B), to ensure the allowable
1.0 foot (5556.14 feet amsl in the Cell 44 LDS sump and 5558.5 feet amsl
in the Cell 48 sump) above the lowest point on the lower flexible
membrane liner is not exceeded). The attached Figures 64 and 68 (Cell
44 and 48, respectively), Leak Detection Sump Operating Elevations,
illustrates the relationship between the sump elevation, the lowest point on
the lower flexible membrane liner and the pump-on solution elevation for
the leak detection pump. The pump also has manual start and stop
controls. The pump will operate until the solution is drawn down to the
lowest level possible, expected to be approximately 4 inches above the
lowest level of the sump (approximate elevation 5554.0 and 5555.77 ft.
amsl for Cells 44 and 48, respectively). The pump discharge is equipped
with a 1.5 inch flow meter, EPS Paddle Wheel Flowsensor, or equal, that
reads the pump discharge in gallons per minute, and records total gallons
pumped. The flow rate and total gallons are recorded by the Inspector on
the weekly inspection form. The leak detection pump is installed in the
horizontal section of the 18 inch, perforated section of the PVC collection
N:\Cell 4BVanuar-.v 2l Submittals and revisions BAT O&lv1\Cell 4A, and 4B O M Plan Rev 2.2 redline'docN'.\€ell
lBUanuary 2gl I iubmitels and novisions fer Gell lB\e&M flan 0l,l0,l l\Gell 11\ and 48 e il{ Plon Rev 2J
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Cell 4A BAT Monitoring, Operations and Maintenance Plan 9l+lL[2010 Revision
Denison2.2l
pipe. The distance from the top flange face, at the collection pipe invert,
to the centerline of the 225 degree elbow is 133.4 feet in Cell 4,{ and
135.6 feet in Cell 48, and the vertical height is approximately 45 feet in
Celt 4A and approximately 42.5 feet in Cell 48. The pump is installed at
least 2 feet beyond the centerline of the elbow. The bottom of the pump
will be installed in the leak detection sump at least 135.4 feet in Cell 4A
and 137.6 feet in Cell 48 or more from the top of the flange invert. A
pressure transducer installed within the pump continuously measures the
solution head and is programmed to start and stop the pump within the
ranges specified above. The attached Figure 5, illustrates the general
configuration of the pump installation.
A spare leak detection pump with pressure transducer, flow meter, and
manufacturer recommended spare parts for the pump confoller and water
level data collector will be maintained in the Mill warehouse to ensure that
the pump and controller on either cell can be replaced and operational
within 24 hours of detection of a failure of the pumping system. The root
cause of the equipment failure will be documented in a report to Mill
management with recommendations for prevention of a re-occurrence.
Slimes Drain System
(i) A pump, Tsurumi Model # KTZ23.7-62 stainless steel, or equal, will be
placed inside of the slimes drain access riser pipe of each cell and a near
as possible to the bottom of the slimes drain sump. The bottom of the
slimes drain sump in Cell 44 and Cell 48 are 38 and 35.9 feet below a
water level measuring point, respectively, at the centerline of the slimes
drain access pipe, near the ground surface level. Each pump discharge
will be equipped with a 2 inch flow meter , EIH Model #33, or equal, that
reads the pump discharge in gallons per minute, and records total gallons
pumped. The flow rate and total gallons will be recorded by the Inspector
on the weekly inspection form.
(ii) The slimes drain pumps will be on adjustable probes that allow the pumps
to be set to start and stop on intervals determined by Mill management.
(iii)The Cell 4A and Cell 48 slimes drain pumps will be checked weekly to
observe that they are operating and that the level probes are set properly,
which is noted on the Weekly Tailings Inspection Form. If at any time
either pump is observed to be not working properly, it will be repaired or
replaced within 15 days;
(iv)Depth to wastewater in the Cell 4A and Cell 48 slimes drain access riser
pipes shall be monitored and recorded weekly to determine maximum and
minimum fluid head before and after a pumping cycle, respectively. All
head measurements must be made from the same measuring point, to the
nearest 0.01 foot. The results will be recorded as depth-in-pipe
measurements on the Weekly Tailings Inspection Form;
NtCell 4BUanuary 2l Submittals and revisions BAT O&lv1\Cell 4A and 48 O M Plan Rev 2.2 redline.docN'.\Cell
lBUanuryS0ll SuknitelsandRevisiensfor€eU 1B\e&MPlangl,l0,lilCell lAand IBO MPlanRsv?'l
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Page 14
Cell 4A BAT Monitoring, Operations and Maintenance Plan gl+lUtz0l0 Revision
Denison 2.2*
(v) On a monthly basis, each slimes drain pump will be turned off and the
wastewater in the slimes drain access pipe will be allowed to stabilize for
at least 90 hours. Once the water level has stabilized (based on no change
in water level for three (3) successive readings taken no less than one (1)
hour apart) the water level of the wastewater will be measured and
recorded as a depth-in-pipe measurement on the Monthly Inspection Data
form, by measuring the depth to water below the water level measuring
point on the slimes drain access pipe;
The slimes drain pumps for each cell will not be operated until Mill management
has determined that no additional process solutions will be discharged to that cell,
and the cell has been partially covered with the first phase of the reclamation cap.
The long term effectiveness and performance of the slimes drain dewatering will
be evaluated on the same basis as the currently operating slimes drain system for
CeIl2.
Tailings Emersencies
Inspectors will notify the Radiation Safety Officer and/or Mill management immediately
if, during their inspection, they discover that an abnormal condition exists or an event has
occurred that could cause a tailings emergency. Until relieved by the Environmental or
Radiation Technician or Radiation Safety Officer, inspectors will have the authority to
direct resources during tailings emergencies.
Any major catastrophic events or conditions pertaining to the tailings area should be
reported immediately to the Mill Manager or the Radiation Safety Officer, one of whom
will notiff Corporate Management. If dam failure occurs, notify your supervisor and the
Mill Manager immediately. The Mill Manager will then notifi Corporate Management,
MSHA (303-231-5465), and the State of Utah, Division of Dam Safety (801-538-7200).
€€l}4+Solution Freeboard Calculations
The manimum tailings cell pond wastewater levels in Cell l, Cell 2,Cell3, Cell4A, and
Cell48 are regulated by condition 10.3 of the White Mesa Mill 1le.(z) Materials
License.
Condition 10.3 states that "Freeboard limits, stormwater and wastewater management for
the tailings cells shall be determined as follows:
A. The freeboard limit for Cell I shall be set annually in accordance
with the procedures set out in Section 3.0 to Appendix E of the
previously approved NRC license application, including the
January 10, 1990 Drainage Report. Discharge of any surface water
or wastewater from Cell I is expressly prohibited.
B. The freeboard limit for Cells 3,4A and 48 shall be recalculated
N:\Cell 4BVanuary 21 Submittals and revisions BAT O&ld\Cell 4A and 4B O M Plan Rev 2.2 redline.docN;\Gell
lBUanuary 20t I Submittels and Revisiens fer €eU 4B\e&M Plan 0l,l0,l l\Gell llt and lB e M Phn Rev 2,1
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Page 15
Cell 4A,' BAT Monitoring, Operations and Maintenance Plan gl+lU20l0 Revision
Denison2.2l
annually in accordance with the procedures established by the
Executive Secretary. Said calculations for freeboard limits shall be
submitted as part of the Annual Technical Evaluation Report
(ATER), as described in Conditionl2.3 below [of the licesnse and
not included hereinl.C. The discharge of any surface water, stormwater, or wastewater
from Cells 3,4A, and 48 shall only be through an Executive
Secretary authorized spillway structure. [Applicable NRC
Amendment:l6l [Applicable UDRC Amendment: 3] [Applicable
UDRC Amendment:4]"
The freeboard limits set out in Section 6.3 of the DMT Plan are intended to capture the
Local 6-hour Probable Maximum Precipitation (PMP) event, which was determined in
the January 10, 1990 Drainage Report for the White Mesa site to be 10 inches.
Based on the PMP storm event, the freeboard requirement for Cell 1 is a maximum
operating water level of 5615.4 feet above mean sea level (amsl). The Cell 1 freeboard
limit is not affected by operations or conditions in Cells 2,3,4A, or 48.
Cells 2 and 3 have no freeboard limit because those Cells are full or near full of tailings
solids. Cell 4,{ has no freeboard limit because it is assumed that all precipitation falling
on Cell 4A will overflow to Cell 48. All precipitation falling on Cell 2,3, and 4A and
the adjacent drainage areas must be contained in Cell48. The flood volume from the
PMP event over the Cell2,3, and Cell 4A pond areas, plus the adjacent drainage areas,
which must be contained in Cell48, is I59.4 acre-feet of water.
The flood volume from the PMP event over the Cell4A area is 36 acre-feet of water (40
acres, plus the adj acent drainage area of 3 .25 acres, times the PMP of I 0 inches). For the
purposes of establishing the freeboard in Cell48, it is assumed Cell4A has no freeboard
limit and all of the flood volume from the PMP event will be contained in Cell48. The
flood volume from the PMP event over the Cell48 arca is 38.1 acrc-fcct of watcr (40
acres, plus the adjacent drainage areaof 5.7 acres, times the PMP of l0 inches). This
would result in a total flood volume of 197 .5 acre-feet, including the I23.4 acre-feet of
solution from Cells 2 and 3 and 36 acre-feet of solution from Cells 2, 3, and 4,{ that must
be contained in Cell48. The procedure for calculating the freeboard limit for Cell 48 is
set out in the DMT Plan.
The Groundwater Quality Discharge Permit, No. UGW370004, for the White Mesa Mill
requires that the minimum freeboard be no less than 3.0 feet for Cells 1,4A, and 48 but
based on License condition 10.3 and the procedure set out in the DMT Plan, the
freeboard limits for Cells 1,4A, and 48 will be at least three feet.
Figure 7, Hydraulic Profile Schematic, shows the relationship between the Cells, and the
relative elevations of the solution pools and the spillway elevations.
The required freeboard for Cells 'lA arrd 48 will be recalculated annually.
N:\Cell 4BVanuarv 2l Submitals and revisions BAT O&tvflCell 4,A, and 4B O M Plan Rev 2.2 redline.docE*\Cell
lBUanuaryS0ll SubmiealsandRevisiensferGeU4B\e&MPlanOlJSll\€e[4Aand49e MPhnRsvS,l
Page 16
Attachments
10)
I t)
r)
2)
Cell 4A BAT Monitoring, Operations and Maintenance Plan 9l+lL[2010 Revision
Denison2.24
Figures lA and 1B, Initial Filling Plan, Geosyntec Consultants
Figure 2A and 28, Initial Filling Plan, Details and Sections, Geosyntec
Consultants
Figure 34 and 38, Initial Filling Plan, Solution and Slurry Pipeline Routes,
Geosyntec Consultants
Figure 4,A' and 48,Interim Filling Plan, Geosyntec Consultants
Figure 5, Leak Detection System Sumps for Cell 44 and 4B, Geosyntec
Consultants
Figure 6A and 68, Leak Detection Sump Operating Elevations, Geosyntec
Consultants
Figure 7, Hydraulic Profile Schematic
Cell4,A, and Cell48 Freeboard Calculations
Table 1A, Calculated Action leakage Rates for Various Head Conditions,
Cell 44, White Mesa Mill, Blanding, Utah, Geosyntec Consultants
Table lB, Calculated Action leakage Rates for Various Head Conditions,
Cell48, White Mesa Mill, Blanding, Utah, Geosyntec Consultants
White Mesa Mill Tailings Management System and Discharge Minimization
Technology (DMT) Monitoring Plan.
3)
4)
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6)
7)
8)
e)
N:\Cell 4BUanuary 2l Submittals and revisions BAT O&llACell 4A and 48 O M Plan Rev 2.2 redline.docN:\Gell
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Page 18
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6eosynfec Consuftonts Table 1A
Calculated Action Leakage Rates for Various Head Conditions
Cell 44, White Mesa Mifl
Blanding Utah
Hsad Above linsr
$ystem {fnst}
talculated Actlon Le*kap Rate
(gallonslacraldeyl
5 222"fi4
10 314.S
r5 $84.58
?0 444"S8
25 49fi,5
30 543,88
3S 587.5
37 sff4.0
Geosyntec Consultants Table 18
Calculated Action Leakage Rates for Various Head Conditions
Cell 48, White Mesa Mill
Bfanding, Utah
Head Abo*e Llner System
{feetl
ffimulaidil Action Leakase Rate
{gallon slaweldaVl
5 zLL,4
10 317.0
15 369,9
2A 422,7
25 475,S
30 578"4
35 570,0
37 58L,2
0ll2ll201 I Revision DenisonZ.2
Cell 4[and 4B BAT Monitoringo Operations and Maintenance Plall.
Introduction
Construction of Cell44 was authorized by the Utah Department of Environmental
Quality, Division of Radiation Control ("DRC) on June 25,2007. The construction
authoization provided that Cell 4,4. shall not be in operation until after a BAT
Monitoring, Operations and Maintenance Plan is submitted for Executive Secretary
review and approval. The Plan shall include requirements in Part I.F.3 of the
Groundwater Discharge PermitNo. UGW370004 ("GWDP") and fulfill the
requirements of Parts LD.6,I.E.8, and I.F.9 of the GWDP.
Construction of Cell 48 was authorized by DRC on June 21,2010. The construction
authorization provided that Cell 48 shall not be in operation until after a BAT
Monitoring, Operations and Maintenance Plan is submitted for Executive Secretary
review and approval. The Plan shall include requirements in Part I.F.3 of the GWDP and
fulfill the requirements of Parts I.D.l2,l.E.l2, and I.F.9 of the GWDP
Cell Desien
Tailings Cell4A consists of the following major elements:
a) Dikes - consisting of earthen embankments of compacted soil, constructed
between 1989-1990, and composed of four dikes, each including a l5-foot
wide road at the top (minimum). On the north, east, and south margins these
dikes have slopes of 3H to lV. The west dike has an interior slope of 2H to
lV. Width of these dikes varies; each has a minimum crest width of at least
15 feet to support an access road. Base width also varies from 89-feet on the
east dike (with no exterior embankment), to 211-feet at the west dike.
b) Foundation - including subgrade soils over bedrock materials. Foundation
preparation included excavation and removal of contaminated soils,
compaction of imported soils to a maximum dry density of 90%. Floor of
Cell 4A, has an average slope of lYo that grades from the northeast to the
southwest corners.
c) Tailings Capacity - the floor and inside slopes of Cell4.{ encompass about 40
acres and have a maximum capacity of about 1.6 million cubic yards of
tailings material storage (as measured below the required 3-foot freeboard).
d) Liner and Leak Detection Systems - including the following layers, in
descending order:
l) Primary Flexible Membrane Liner (FML) - consisting of impermeable 60
mil high density polyethylene (HDPE) membrane that extends across both
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the entire cell floor and the inside side-slopes, and is anchored in a tench
at the top of the dikes on all four sides. The primary FML will be in direct
physical contact with the tailings material over most of the Cell4A floor
area. In other locations, the primary FML will be in contact with the
slimes drain collection system (discussed below).
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2) Leak Detection System - includes a permeable HDPE geonet fabric that
extends across the entire area under the primary FML in Cell 4A, and
drains to a leak detection sump in the southwest corner. Access to the leak
detection sump is via an l8-inch inside diameter (ID) PVC pipe placed
down the inside slope, located between the primary and secondary FML
liners. At its base this pipe will be surrounded with a gravel filter set in
the leak detection sump, having dimensions of 10 feet by 10 feet by 2 feet
deep. In turn, the gravel filter layer will be enclosed in an envelope of
geotextile fabric. The purpose of both the gravel and geotextile fabric is to
serve as a filter.
3) Secondary FML - consisting of an impermeable 60-mil HDPE membrane
found immediately below the leak detection geonet. Said FML also
extends across the entire Cell 4,A. floor, up the inside side-slopes and is
also anchored in a trench at the top of all four dikes.
4) Geosynthetic Clay Liner - consisting of a manufactured geosynthetic clay
liner (GCL) composed of O.2-inch of low permeability bentonite clay
centered and stitched between two layers of geotextile. Prior to disposal
of any wastewater in Cell 4'A,, the Permittee shall demonstrate that the
GCL has achieved a moisture content of at least 50% by weight. This
item is a revised requirement per DRC letter to DUSA dated September
28,2007
e) Slimes Drain Collection System - including a two-part system of strip drains
and perforated collection pipes both installed immediately above the primary
FML, as follows:
l) Horizontal Strip Drain System - is installed in a heningbone pattern
across the floor of Cell 4A that drain to a "backbone" of perforated
collection pipes. These strip drains are made of a prefabricated two-part
geo-composite drain material (solid polymer drainage strip) core
surrounded by an envelope of non-woven geotextile filter fabric. The strip
drains are placed immediately over the primary FML on SO-foot centers,
where they conduct fluids downgradient in a southwesterly direction to a
physical and hydraulic connection to the perforated slimes drain collection
pipe. A series of continuous sand bags, filled with filter sand cover the
strip drains. The sand bags are composed of a woven polyester fabric
filled with well graded filter sand to protect the drainage system from
plugging.
2) Horizontal Slimes Drain Collection Pipe System - includes a "backbone"
piping system of 4-inch ID Schedule 40 perforated PVC slimes drain
collection (SDC) pipe found at the downgradient end of the strip drain
lines. This pipe is in turn overlain by a berm of gravel that runs the entire
diagonal length of the cell, strrounded by a geotextile fabric cushion in
immediate contact with the primary FML. The non-woven geotextile
material is overlain at the surface by a woven geotextile fabric, which is
ballasted laterally by sandbags on each side of the backbone of the berm.
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In turn, the gravel is overlain by a layer of non-woven geotextile to serve
as an additional filter material. This perforated collection pipe serves as
the "backbone" to the slimes drain system and runs from the far northeast
corner downhill to the far southwest corner of Cell 44 where it joins the
slimes drain access pipe.
3) Slimes Drain Access Pipe - consisting of an l8-inch ID Schedule 40 PVC
pipe placed down the inside slope of Cell 4,A. at the southwest corner,
above the primary FML. Said pipe then merges with another horizontal
pipe of equivalent diameter and material, where it is enveloped by gravel
and nonwoven geotextile that serves as a cushion to protect the primary
FML. The non-woven geotextile material is overlain at the surface by a
woven geotextile fabric, which is ballasted by sandbags.A reducer
connects the horizontal l8-inch pipe with the 4-inch SDC pipe. At some
future time, a pump will be set in this l8-inch pipe and used to remove
tailings wastewaters for purposes of de-watering the tailings cell.
0 Dike Splash Pads - A minimum of eight (8) 2O-foot wide splash pads are
installed on the interior dike slopes to protect the primary FML from abrasion
and scouring by tailings slurry. These pads consist of an extra layer of 60 mil
HDPE membrane that is placed down the inside slope of Cell4A, flom the top
of the dike and down the inside slope. The pads extend to a point 5-feet
beyond the toe of the slope to protect the liner bottom during initial startup of
the Cell. The exact location of the splash pads is detailed on the As-Built
Plans and Specifications.
g) Rub Protection Sheets - In addition to the splash pads described in f) above,
rub sheets are installed beneath all piping entering or exiting Cell 4.{ that is
not located directly on the splash pads.
h) Emergency Spillway - a concrete lined spillway constructed near the western
corner of the north dike to allow emergency runoff from Cell 3 into Cell 44.
This spillway will be limited to a 6-inch reinforced concrete slab set directly
over the primary FML in a 4-foot deep trapezoidal channel. A second
spillway has been constructed in the southwest comer of Cell 4A to allow
emergency runoff from Cell 4A into Cell 48. All stormwater runoff and
tailings wastewaters not retained in Cells 3 and 4A, will be managed and
contained in Cell 48, including the Probable Maximum Precipitation and
flood event.
Tailings Cell4B consists of the following major elements:
a) Dike - consisting of a newly-constructed dike on the south side of the cell
with a l5-foot wide road at the top (minimum) to support an access road.
The grading plan for the Cell 4B excavation includes interior slopes of 2H
to lV. The exterior slope of the southern dike will have the typical slopes
of 3H to lV. Limited portions of the Cell 48 interior sideslopes in the
northwest corner and southeast corner of the cell (where the slimes drain
and leak detection sump will be located) will also have a slope of 3H to
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lV. The base width of the southem dike varies from approximately 100
feet at the western end to approximately 190 feet at the eastern end of the
dike, with no exterior embankment present on any other side of the cell.
b) Foundation - including subgrade soils over bedrock materials. Foundation
preparation included 6-inch over excavation of rock and placement and
compaction of imported soils to a maximum dry density of 90%o at a
moisture content between +3Yo and -3Vo of optimum moisture content, as
determined by ASTM D-1557. The floor of Cell 48 has an average slope
of lo/o that grades from the northwest comer to the southeast comer.
c) Tailings Capacity - the floor and inside slopes of Cell 48 encompass
about 45 acres and the cell will have a water surface area of 40 acres and a
maximum capacity of about 1.9 million cubic yards of tailings material
storage (as measured below the required 3-foot freeboard).
d) Liner and Leak Detection Systems - including the following layers, in
descending order:
l) Primary Flexible Membrane Liner (FML) - consisting of 60 mil high
density polyethylene (HDPE) membrane that extends across both the
entire cell floor and the inside side-slopes, and is anchored in a trench at
the top of the dikes on all four sides. The primary FML will be in direct
physical contact with the tailings material over most of the Cell 48 floor
area. In other locations, the primary FML will be in contact with the
slimes drain collection system (discussed below).
2) Leak Detection System - includes a permeable HDPE geonet fabric that
extends across the entire area under the primary FML in Cell 48, and
drains to a leak detection sump in the southeast corner. Access to the leak
detection sump is via an l8-inch inside diameter (ID) PVC pipe placed
down the inside slope, located between the primary and secondary FML
liners. At its base this pipe will be surrounded with a gtavel filter set in
the leak detection sump, having dimensions of l0 feet by l0 feet by 2 feet
deep. In turn, the gravel filter layer will be enclosed in an envelope of
geotextile fabric. The purpose of both the gravel and geotextile fabric is to
serve as a filter.
3) Secondary FML - consisting of a 60-mil HDPE membrane found
immediately below the leak detection geonet. Said FML also extends
across the entire Cell 48 floor, up the inside side-slopes and is also
anchored in a trench at the top of all four dikes.
4) Geosynthetic Clay Liner - consisting of a manufactured geosynthetic clay
liner (GCL) composed of O.2-inch of low permeability bentonite clay
centered and stitched between two layers of geotextile. Prior to disposal
of any wastewater in Cell 4B, the Permittee shall demonstrate that the
GCL has achieved a moisture content of at least 50%by weight.
e) Slimes Drain Collection System - including a two-part system of strip
drains and perforated collection pipes both installed immediately above
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the primary FML, as follows:
1) Horizontal Strip Drain System - is installed in a heningbone pattern
across the floor of Cell 49 that drain to a "backbone" of perforated
collection pipes. These strip drains are made of a prefabricated two-part
geo-composite drain material (solid polymer drainage strip) core
surrounded by an envelope of non-woven geotextile filter fabric. The strip
drains are placed immediately over the primary FML on 50-foot centers,
where they conduct fluids downgradient in a southeasterly direction to a
physical and hydraulic connection to the perforated slimes drain collection
pipe. A series of continuous sand bags, filled with filter sand cover the
strip drains. The sand bags are composed of a woven polyester fabric
filled with well graded filter sand to protect the drainage system from
plugging.
2) Horizontal Slimes Drain Collection Pipe System - includes a "backbone"
piping system of 4-inch ID Schedule 40 perforated PVC slimes drain
collection (SDC) pipe found at the downgradient end of the strip drain
lines. This pipe is in tum overlain by a berm of gravel that runs the entire
diagonal length of the cell, surrounded by a geotextile fabric cushion in
immediate contact with the primary FML. In turn, the gravel is overlain
by a layer of non-woven geotextile to serve as an additional filter material.
The non-woven geotextile material is overlain at the surface by a woven
geotextile fabric, which is ballasted by sandbags. This perforated
collection pipe serves as the "backbone" to the slimes drain system and
runs from the far northwest corner downhill to the far southeast corner of
Cell48 where it joins the slimes drain access pipe.
3) Slimes Drain Access Pipe - consisting of an l8-inch ID Schedule 40 PVC
pipe placed down the inside slope of Cell 48 at the southeast comer,
above the primary FML. Said pipe then merges with another horizontal
pipe of equivalent diameter and material, where it is enveloped by gravel
and non-woven geotextile that serves as a cushion to protect the primary
FML. The non-woven geotextile material is overlain at the surface by a
woven geotextile fabric, which is ballasted laterally by sandbags on each
side of the backbone of the berm. A reducer connects the horizontal 18-
inch pipe with the 4-inch SDC pipe. At some future time, a pump will be
set in this l8-inch pipe and used to remove tailings wastewaters for
purposes of de-watering the tailings cell.
0 Cell48 North and East Dike Splash Pads - Nine 20-foot-wide splash pads
will be constructed on the north and east dikes to protect the primary FML
from abrasion and scouring by tailings slurry. These pads will consist of
an extra layer of textured, 60 mil HDPE membrane that will be installed in
the anchor trench and placed down the inside slope of Cell 4B, from the
top of the dike, under the inlet pipe, and down the inside slope to a point at
least 5 feet onto the Cell 48 floor beyond the toe of the slope.
g) Rub Protection Sheets - In addition to the splash pads described in f)
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above, rub sheets are installed beneath all piping entering or exiting Cell
48 that is not located directly on the splash pads.
h) Emergency Spillway - a concrete lined spillway constructed near the
southern comer of the east dike to allow emergency runoff from Cell 4,{
into Cell 48. This spillway will be limited to a 6-inch reinforced concrete
slab, with a welded-wire fabric installed within its midsection, set atop a
cushion geotextile placed directly over the primary FML in a 4-foot deep
trapezoidal channel. A 100 foot wide, 60 mil HDPE geomembrane splash
pad will be installed beneath the emergency spillway. No other spillway
or overflow structure will be constructed at Cell 48. All stormwater
runoff and tailings wastewaters not retained in Cells 2,3 and 4,{, will be
managed and contained in Cell 48, including the Probable Maximum
Precipitation and flood event.
Cell Operation
Solution Discharge to Cell4,A.
Cell 4A will initially be used for storage and evaporation of process solutions
from the Mill operations. These process solutions will be from the
uranium/vanadium solvent extraction circuit, or transferred from Cell I
evaporation pond or the free water surface from Cell 3, or transferred from Cell2
tailings dewatering operations. The solution will be pumped to Cell 4,{ through 6
inch or 8 inch diameter HDPE pipelines. The initial solution discharge will be in
the southwest comer of the Cell. The solution will be discharged in the bottom
of the Cell, away from any sand bags or other installation on the top of the FML.
Building the solution pool from the low end of the Cell will allow the solution
pool to gradually rise around the slimes drain strips, eliminating any damage to
the strip drains or the sand bag cover due to solution flowing past the drainage
strips. The solution will eventually be discharged along the dike between Cell 3
and Cell44, utilizing the Splash Pads described above. The subsequent discharge
of process solutions will be near the floor of the pond, through a discharge header
designed to discharge through multiple points, thereby reducing the potential to
damage the Splash Pads or the Slimes Drain system. At no time, subsequent to
initial filling, will the solution be discharged into less than 2 feet of solution. As
the cell begins to fill with solution the discharge point will be pulled back up the
Splash Pad and allowed to continue discharging at or near the solution level.
Solution Discharse to Cell48
Cell 48 will initially be used for storage and evaporation of process solutions
from the Mill operations. These process solutions will be from the
uranium/vanadium solvent extraction circuit, or transferred from Cell 1
evaporation pond or the free water surface from Cell 3 or Cell 4A., or transferred
from Cell 2 dewatering operations. The solution will be pumped to Cell 48
through 6 inch or 8 inch diameter HDPE pipelines. The initial solution discharge
will be in the southeast corner of the Cell. The discharge pipe will be routed
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down the Splash Pad provided in the southeast corner of the Cell at the spillway
to protect the primary FML. The solution will be discharged in the bottom of the
Cell, away from any sand bags or other installation on the top of the FML.
Building the solution pool from the low end of the Cell will allow the solution
pool to gradually rise around the slimes drain strips, eliminating any damage to
the strip drains or the sand bag cover due to solution flowing past the drainage
strips. The solution will eventually be discharged along the dike between Cell 3
and Cell 48, utilizing the Splash Pads described above. The subsequent discharge
of process solutions will be near the floor of the pond, through a discharge header
designed to discharge through multiple points, thereby reducing the potential to
damage the Splash Pads or the Slimes Drain system. At no time, subsequent to
initial filling, will the solution be discharged into less than 2 feet of solution. As
the cell begins to fill with solution the discharge point will be pulled back up the
Splash Pad and allowed to continue discharging at or near the solution level.
Initial Solids Discharge into Cell4,A.
Once Cell 4A is needed for storage for tailings solids the slurry discharge from
No. 8 CCD thickener will be pumped to the cell through 6 inch or 8 inch diameter
HDPE pipelines. The pipelines will be routed along the dike between Cell 3 and
Cell 44, with discharge valves and drop pipes extending down the Splash Pads to
the solution level. One or all of the discharge points can be used depending on
operational considerations. Solids will settle into a cone, or mound, of material
under the solution level, with the courser fraction settling out closer to the
discharge point. The initial discharge locations are shown on Figure 1A. Figure
24 illustrates the general location of the solution and slurry discharge pipelines
and control valve locations. The valves are 6" or 8" stainless steel knife-gate
valves. The initial discharge of sluny will be at or near the toe of the Cell slope
and then gradually moved up the slope, continuing to discharge at or near the
water surface. This is illustrated in Section A-A on Figure 2A. Because of the
depth of Cell 44, each of the discharge points will be utilized for an extended
period of time before the cone of material is above the maximum level of the
solution. The discharge location will then be moved firther to the interior of the
cell allowing for additional volume of solids to be placed under the solution level.
The solution level in the cell will vary depending on the operating schedule of the
Mill and the seasonal evaporation rates. The tailings shury will not be allowed to
discharge directly on to the Splash Pads, in order to further protect the FML. The
tailings slurry will discharge directly in to the solution contained in the Cell, onto
an additional protective sheet, or on to previously deposited tailings sand.
Initial Solids Discharge into Cell48
Once Cell 48 is needed for storage for tailings solids the slurry discharge from
No. 8 CCD thickener will be pumped to the cell through 6 inch or 8 inch diameter
HDPE pipelines. The pipelines will be routed along the dike between Cell 3 and
Cell 48, with discharge valves and drop pipes extending down the Splash Pads to
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the solution level. One or all of the discharge points can be used depending on
operational considerations. Solids will settle into a cone, or mound, of material
under the solution level, with the courser fraction settling out closer to the
discharge point. The initial discharge locations are shown on Figure lB. Figure
28 illustrates the general location of the solution and slurry discharge pipelines
and control valve locations. The valves are 6" or 8" stainless steel knife-gate
valves. The initial discharge of slurry will be at or near the toe of the Cell slope
and then gradually moved up the slope, continuing to discharge at or near the
water surface. This is illustrated in Section A-A on Figure 28. Because of the
depth of Cell 48, each of the discharge points will be utilized for an extended
period of time before the cone of material is above the maximum level of the
solution. The discharge location will then be moved further to the interior of the
cell allowing for additional volume of solids to be placed under the solution level.
The solution level in the cell will vary depending on the operating schedule of the
Mill and the seasonal evaporation rates. The tailings slurry will not be allowed to
discharge directly on to the Splash Pads, in order to further protect the FML. The
tailings slurry will discharge directly in to the solution contained in the Cell, onto
an additional protective sheet, or on to previously deposited tailings sand.
Equipment Access to Cell4,A. and Cell48
Access will be restricted to the interior portion of the cells due to the potential to
damage the flexible membrane liners. Only low pressure rubber tired all terrain
vehicles or foot traffic will be allowed on the flexible membrane liners. Personnel
are also cautioned on the potential damage to the flexible membrane liners
through the use and handling of hand tools and maintenance materials.
Reclaim Water System at Cell44,
A p,rmp barge and solution recovery system is operating in the southwest corner
of the cell to pump solution from the cell for water balance purposes or for re-use
in the Mill process. Figure 3A illustrates the routing of the solution return
pipeline and the location of the pump barge. The pump barge will be constructed
and maintained to ensure that the flexible membrane liner is not damaged during
the initial filling of the cell or subsequent operation and maintenance activities.
The condition of the pump barge and access walkway will be noted during the
weekly Cell inspections.
Reclaim Water Slistem at Cell48
A pump barge and solution recovery system will be installed in the southeast
corner of the cell to pump solution from the cell for water balance purposes or for
re-use in the Mill process. Figure 38 illustrates the routing of the solution return
pipeline and the location of the pump barge. The pump barge will be constructed
and maintained to ensure that the flexible membrane liner is not damaged during
NlCell 4B\January 2l Submittals and revisions BAT O&\[\Cell 4,4' and 48 O M Plan Rev 2.2 clean.docN:\Cell
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Cell 44' BAT Monitoring, Operations and Maintenance Plan 0ll2ll20l0 Revision
Denison2.2
the initial filling of the cell or subsequent operation and maintenance activities.
The condition of the pump barge and access walkway will be noted during the
weekly Cell inspections.
Interim Solids Discharge to Cell4.A.
Figure 4A illustrates the progression of the slurry discharge points around the
north and east sides of Cell 4A. Once the tailings solids have been deposited
along the north and east sides of the Cell, the discharges points will subsequently
be moved to the sand beaches, which will eliminate any potential for damage to
the liner system.
Interim Solids Discharge to Cell48
Figure 48 illustrates the progression of the slurry discharge points around the
north and east sides of Cell 48. Once the tailings solids have been deposited
along the north and east sides of the Cell, the discharges points will subsequently
be moved to the sand beaches, which will eliminate any potential for damage to
the liner system.
Liner Maintenance and OA/OC for Cell4A
Any construction defects or operational damage discovered during observation of
the flexible membrane liner will be repaired, tested and documented according to
the procedures detailed in the approved Revised Construction Quality
Assurance Plan for the Construction of the Cell 4A Lining System' May
2007, by GeoSyntec Consultants.
Liner Maintenance and OA/OC for Cell48
Any construction defects or operational damage discovered during observation of
the flexible membrane liner will be repaired, tested and documented according to
the procedures detailed in the approved Construction Quality Assurance Plan
for the Construction of the CeIl 48 Lining System, October 2009, by
Geosyntec Consultants.
BAT Performance Standards for Tailinss Cell4A and 48
DUSA will operate and maintain Tailings Cell4,A, and 4B so as to prevent release of
wastewater to groundwater and the environment in accordance with this BAT Monitoring
Operations and Maintenance Plan, pursuant to Part I.H.8 of the GWDP. These
performance standards shall include:
NtCell 4BUanuary 2l Submittals and revisions BAT O&tvl\Cell 4A and 48 O M Plan Rev 2.2 clean.docN:\Cell
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Cell 4A BAT Monitoring, Operations and Maintenance Plan 0ll2ll20l0 Revision
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1) Leak Detection System Pumping and Monitoring Equipment - the
leak detection system pumping and monitoring equipment in each cell
includes a submersible pump, pump controller, water level indicator (head
monitoring), and flow meter with volume totalizer. The pump controller
is set to maintain the manimum level in the leak detection system in each
cell at no more than I foot above the lowest level of the secondary flexible
membrane, not including the sump. A second leak detection pump with
pressure transducer, flow meter, and manufacturer recommended spare
parts for the pump controller and water level data collector is maintained
in the Mill warehouse to ensure that the pump and controller can be
replaced and operational within 24 hours of detection of a failure of the
pumping system. The root cause of the equipment failure will be
documented in a report to Mill management with recornmendations for
prevention of a re-occuffence.
Maximum Allowable Head - the Permittee shall measure the fluid head
above the lowest point on the secondary flexible membrane in each cell
by the use of procedures and equipment specified in the White Mesa
Mill Tailings Management System and Discharge Minimization
Technology (DMT) Monitoring Plan, 10/10 Revision: Denison-10.2'
or the currently approved DMT Plan. Under no circumstance shall fluid
head in the leak detection system sump exceed a l-foot level above the
lowest point in the lower flexible membrane liner, not including the
sump.
Maximum Allowable Daily LDS Flow Rates - the Permittee shall
measure the volume of all fluids pumped from each LDS on a weekly
basis, and use that information to calculate an average volume pumped
per day. Under no circumstances shall the daily LDS flow volume
exceed 24,160 gallons/day for Cell4A or 26,145 gallons/day for Cell
4ts. 'l'he maximum daily LDS flow volume will be compared against the
measured cell solution levels detailed on the attached Table lA or lB for
Cells 4A or 48, respectively, to determine the maximum daily allowable
LDS flow volume for varying head conditions in the cell.
3-foot Minimum Vertical Freeboard Criteria - the Permittee shall
operate and maintain wastewater levels to provide a 3-foot Minimum of
vertical freeboard in Tailings Cell4,A. and Cell48. Said measurements
shall be made to the nearest 0.1 foot.
Slimes Drain Recovery Head Monitoring - immediately after the
Permittee initiates pumping conditions in the Tailings Cell4,A, or Cell
48 slimes drain system, monthly recovery head tests and fluid level
measurements will be made in accordance with a plan approved by the
DRC Executive Secretary. The slimes drain system pumping and
monitoring equipment, includes a submersible pump, pump controllero
water level indicator (head monitoring), and flow meter with volume
NlCell 4BUanuary 2l Submittals and revisions BAT O&lvl\Cell 4A and 48 O M Plan Rev 2.2 clean.docNlCell
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Page 1 I
2)
3)
4)
s)
Cell 44, BAT Monitoring, Operations and Maintenance Plan 0ll2ll20l0 Revision
Denison2.2
totalizer.
Routine Maintenance and Monitorins
Trained personnel inspect the White Mesa tailings system on a once per day basis. Any
abnormal occurrences or changes in the system will be immediately reported to Mill
management and maintenance personnel. The inspectors are trained to look for events
involving the routine placement of tailings material as well as events that could affect the
integrity of the tailings cell dikes or lining systems. The daily inspection reports are
summarized on a monthly basis and reviewed and signed by the Mill Manager.
Solution Elevation
Measurements of solution elevation in Cell4,A, and Cell48 are to be taken by
survey on a weekly basis, and measurements of the beach area in Cell4,{ and Cell
48 with the highest elevation are to be taken by survey on a monthly basis, by the
use of the procedures and equipment specified in the latest approved edition of the
DMT Plan.
Leak Detection System
The Leak Detection System in Cell 4,A. and Cell 48 is monitored on a
continuous basis by use of a pressure transducer that feeds water level
information to an electronic data collector. The water levels are measured
every hour and the information is stored for later retrieval. The water
levels are measured to the nearest 0.10 inch. The data collector is
currently programmed to store 7 days of water level information. The
number ofdays ofstored data can be increased beyond 7 days ifneeded.
The water level data is downloaded to a laptop computer on a weekly
basis and incorporated into the Mill's environmental monitoring data base,
and into the files for weekly inspection reports of the tailings cell leak
detection systems. Within 24 hours after collection of the weekly water
level data, the information will be evaluated to ensure that: 1) the water
level in the Cell 4A and Cell 48 leak detection sumps did not exceed the
allowable level (5556.14 feet amsl in the Cell 4.A LDS sump and 5558.5
feet amsl in the Cell48 sump), and2) the average daily flow rate from the
LDS did not exceed the maximum daily allowable flow rate at any time
during the reporting period. For Cell 4A and Cell 48, under no
circumstance shall fluid head in the leak detection system sump exceed a
l-foot level above the lowest point in the lower flexible membrane liner,
not including the sump. To determine the Maximum Allowable Daily
LDS Flow Rates in the Cell 4,A. and Cell 48 leak detection system, the
total volume of all fluids pumped from the LDS of each cell on a weekly
basis shall be recovered from the data collector, and that information will
N:\Cell 4BVanuary 2l Submittals and revisions BAT O&lv{\Cell 44. and 48 O M Plan Rev 2.2 clean.docN:\Cell
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Cell 4A BAT Monitoring, Operations and Maintenance Plan 0112112010 Revision
Denison2.2
be used to calculate an average volume pumped per day for each cell.
Under no circumstances shall the daily LDS flow volume exceed 24,160
gallons/day from Cell 44. or 26,145 gallons/day from Cell 48. The
maximum daily LDS flow volume will be compared against the measured
cell solution levels detailed on the attached Tables lA and lB, to
determine the maximum daily allowable LDS flow volume for varying
head conditions in Cell 44 and Cell 4B. Any abnormal or out of
compliance water levels must be immediately reported to Mill
management. The data collector on each cell is also equipped with an
audible alarm that sounds if the water level in the leak detection sump
exceeds the allowable level (5556.14 feet amsl in the Cell 4,{ LDS sump
and 5558.5 feet amsl in the Cell 48 sump). The current water level is
displayed at all times on each data collector and available for recording on
the daily inspection form. Each leak detection system is also equipped
with a leak detection pump, EPS Model # 25505-3 stainless steel, or
equal. Each pump is capable of pumping in excess of 25 gallons per
minute at a total dynamic head of 50 feet. Each pump has a 1.5 inch
diameter discharge, and operates on 460 volt 3 phase power. Each pump
is equipped with a pressure sensing transducer to start the pump once the
level of solution in the leak detection sump is approximately 2.25 feet
(elevation 5555.89 in the Cell 4A LDS sump and 5557.69 feet amsl in the
Cell 48 sump) above the lowest level of the leak detection sump (9 inches
[0.75 feet] above the lowest point on the lower flexible membrane liner for
Cell 44. and2ll4 inches [0.19 feet] for Cell 4B), to ensure the allowable
1.0 foot (5556.14 feet amsl in the Cell 4,A, LDS sump and 5558.5 feet amsl
in the Cell 48 sump) above the lowest point on the lower flexible
membrane liner is not exceeded). The attached Figures 64. and 6B (Cell
44, and 48, respectively), Leak Detection Sump Operating Elevations,
illustrates the relationship between the sump elevation, the lowest point on
the lower flexible membrane liner and the pump-on solution elevation for
the leak detection pump. The pump also has manual start and stop
controls. The pump will operate until the solution is drawn down to the
lowest level possible, expected to be approximately 4 inches above the
lowest level of the sump (approximate elevation 5554.0 and 5555.77 ft
amsl for Cells 4,{ and 4B, respectively). The pump discharge is equipped
with a 1.5 inch flow meter, EPS Paddle Wheel Flowsensor, or equal, that
reads the pump discharge in gallons per minute, and records total gallons
pumped. The flow rate and total gallons are recorded by the Inspector on
the weekly inspection form. The leak detection pump is installed in the
horizontal section of the 18 inch, perforated section of the PVC collection
pipe. The distance from the top flange face, at the collection pipe invert,
to the centerline of the 22.5 degree elbow is 133.4 feet in Cell 4A and
135.6 feet in Cell 48, and the vertical height is approximately 45 feet in
Cell 4,A, and approximately 42.5 feet in Cell 48. The pump is installed at
least 2 feet beyond the centerline of the elbow. The bottom of the pump
will be installed in the leak detection sump at least 135.4 feet in Cell 4A
N:\Cell 4BVanuary2l SubmittalsandrevisionsBATO&llACell 44,and48O MPlanRev2.2 clean.docN:\Cell
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Cell 44. BAT Monitoring, Operations and Maintenance Plan 0112112010 Revision
Denison2.2
and 137.6 feet in Cell 48 or more from the top of the flange invert. A
pressure transducer installed within the pump continuously measures the
solution head and is programmed to start and stop the pump within the
ranges specified above. The attached Figure 5, illustrates the general
configuration of the pump installation.
A spare leak detection pump with presstre transducer, flow meter, and
manufacturer recommended spare parts for the pump controller and water
level data collector will be maintained in the Mill warehouse to ensure that
the pump and controller on either cell can be replaced and operational
within 24 hours of detection of a failure of the pumping system. The root
cause of the equipment failure will be documented in a report to Mill
management with recommendations for prevention of a re-occuffence.
(i) A pump, Tsurumi Model # KTZ23.7-62 stainless steel, or equal, will be
placed inside of the slimes drain access riser pipe of each cell and a near
as possible to the bottom of the slimes drain sump. The bottom of the
slimes drain sump in Cell 4A and Cell 48 are 38 and 35.9 feet below a
water level measuring point, respectively, at the centerline of the slimes
drain access pipe, near the ground surface level. Each pump discharge
will be equipped with a 2 inch flow meter,E[H Model #33, or equal, that
reads the pump discharge in gallons per minute, and records total gallons
pumped. The flow rate and total gallons will be recorded by the Inspector
on the weekly inspection form.
(ii) The slimes drain pumps will be on adjustable probes that allow the pumps
to be set to start and stop on intervals determined by Mill management.
(iii)The Cell 4A. and Cell 48 slimes drain pumps will be checked weekly to
observe that they are operating and that the level probes are set properly,
which is noted on the Weekly Tailings Inspection Form. If at any time
either pump is observed to be not working properly, it will be repaired or
replaced within l5 days;
(iv)Depth to wastewater in the Cell 4,A. and Cell 4B slimes drain access riser
pipes shall be monitored and recorded weekly to determine maximum and
minimum fluid head before and after a pumping cycle, respectively. All
head measurements must be made from the same measuring point, to the
nearest 0.01 foot. The results will be recorded as depth-in-pipe
measurements on the Weekly Tailings Inspection Form;
(v) On a monthly basis, each slimes drain pump will be turned off and the
wastewater in the slimes drain access pipe will be allowed to stabilize for
at least 90 hours. Once the water level has stabilized (based on no change
in water level for three (3) successive readings taken no less than one (l)
hour apart) the water level of the wastewater will be measured and
recorded as a depth-in-pipe measurement on the Monthly Inspection Data
form, by measuring the depth to water below the water level measuring
N:\Cell 4BUanuary 2l Submittals and revisions BAT O&M\Cell 44, and 48 O M Plan Rev 2.2 clean.docN:\Cell
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Slimes Drain S
Cell 4A' BAT Monitoring, Operations and Maintenance Plan 0ll2ll20l0 Revision
Denison2.2
point on the slimes drain access pipe;
The slimes drain pumps for each cell will not be operated until Mill management
has determined that no additional process solutions will be discharged to that cell,
and the cell has been partially covered with the first phase of the reclamation cap.
The long term effectiveness and performance of the slimes drain dewatering will
be evaluated on the same basis as the currently operating slimes drain system for
Cell2.
Tailings Emergencies
Inspectors will notify the Radiation Safety Officer and/or Mill management immediately
if, during their inspection, they discover that an abnormal condition exists or an event has
occurred that could cause a tailings emergency. Until relieved by the Environmental or
Radiation Technician or Radiation Safety Offrcer, inspectors will have the authority to
direct resources during tailings emergencies.
Any major catastrophic events or conditions pertaining to the tailings area should be
reported immediately to the Mill Manager or the Radiation Safety Officer, one of whom
will notifr Corporate Management. If dam failure occurs, notit/ your supervisor and the
Mill Manager immediately. The Mill Manager will then notifr Corporate Management,
MSHA (303-231-5465), and the State of Utah, Division of Dam Safety (801-538-7200).
Solution Freeboard Calculations
The maximum tailings cell pond wastewater levels in Cell l, Cell 2,Cell3, Cell4A, and
Cell 48 are regulated by condition 10.3 of the White Mesa Mill I le.(z) Materials
License.
Condition 10.3 states that "Freeboard limits, stormwater and wastewater management for
the tailings cells shall be determined as follows:
The freeboard limit for Cell I shall be set annually in accordance
with the procedures set out in Section 3.0 to Appendix E of the
previously approved NRC license application, including the
January 10, 1990 Drainage Report. Discharge of any surface water
or wastewater from Cell I is expressly prohibited.
The freeboard limit for Cells 3,4A and 48 shall be recalculated
annually in accordance with the procedures established by the
Executive Secretary. Said calculations for freeboard limits shall be
submitted as part of the Annual Technical Evaluation Report
(ATER), as described in Conditionl2.3 below [of the licesnse and
not included hereinl.
The discharge of any surface water, stormwater, or wastewater
from Cells 3,4A, and 48 shall only be through an Executive
NlCell 4BUanuary 2l Submitials and revisions BAT O&lvl\Cell 4A and 48 O M Plan Rev 2.2 clean.docN:\Cell
4BUanuary 2l Submittals and revisions BAT O&M\Cell 44, and 48 O M Plan Rev 2.2 clean.doc
Page 15
A.
B.
C.
Cell 4A BAT Monitoring, Operations and Maintenance Plan 0ll2Il20l0 Revision
Denison2.2
Secretary authorized spillway structure. [Applicable NRL
Amendment:161 [Applicable UDRC Amendment: 3] [Applicable
UDRC Amendment:4]"
The freeboard limits set out in Section 6.3 of the DMT Plan are intended to capture the
Local 6-hour Probable Maximum Precipitation (PMP) event, which was determined in
the January 10, 1990 Drainage Report for the White Mesa site to be 10 inches.
Based on the PMP storm event, the freeboard requirement for Cell 1 is a maximum
operating water level of 5615.4 feet above mean sea level (amsl). The Cell I freeboard
limit is not affected by operations or conditions in Cells 2,3,4A, or 48.
Cells 2 and 3 have no freeboard limit because those Cells are full or near full of tailings
solids. Cell4A has no freeboard limit because it is assumed that all precipitation falling
on Cell 44. will overflow to Cell 48. All precipitation falling on Cell 2,3, and 4A and
the adjacent drainage areas must be contained in Cell48. The flood volume from the
PMP event over the Cell2,3, and Cell 44 pond areas, plus the adjacent drainage areas,
which must be contained in Cell48, is 159.4 acre-feet of water.
The flood volume from the PMP event over the Cell4,A. area is 36 acre-feet of water (40
acres, plus the adjacent drainage arca of 3.25 acres, times the PMP of 10 inches). For the
purposes of establishing the freeboard in Cell 48, it is assumed Cell 4A has no freeboard
limit and all of the flood volume from the PMP event will be contained in Cell48. The
flood volume from the PMP event over the Cell48 area is 38.1 acre-feet of water (40
acres, plus the adjacent drainage areaof 5.7 acres, times the PMP of 10 inches). This
would result in a total flood volume of 197.5 acre-feet, including the 123.4 acre-feet of
solution from Cells 2 and 3 and 36 aue-feet of solution from Cells 2, 3, and 4,{ that must
be contained in Cell 48. The procedure for calculating the freeboard limit for Cell48 is
set out in the DMT Plan.
The Groundwater Quality Discharge Permit, No. UGW370004, for the White Mesa Mill
requires that the minimum freeboard be no less than 3.0 feet for Cells 1,4A, and 48 but
based on License condition 10.3 and the procedure set out in the DMT Plan, the
freeboard limits for Cells 1,4A, and 48 will be at least three feet.
Figure 7, Hydraulic Profile Schematic, shows the relationship between the Cells, and the
relative elevations of the solution pools and the spillway elevations.
The required freeboard for Cell48 will be recalculated annually.
N:\Cell 4BUanuary 2l Submittals and revisions BAT O&l\ACell 44, and 4B O M Plan Rev 2.2 clean.docN:\Cell
4BUanuary 2l Submittals and revisions BAT O&M\Cell 44' and 48 O M Plan Rev 2.2 clean.doc
Page 16
Attachments
10)
11)
1)
2:)
Cell 4,A. BAT Monitoring, Operations and Maintenance Plan 0ll2ll20l0 Revision
Denison2.2
Figures lA and 1B, Initial Filling Plan, Geosyntec Consultants
Figure 2A and 28, Initial Filling Plan, Details and Sections, Geosyntec
Consultants
Figure 34 and 38, Initial Filling Plan, Solution and Slurry Pipeline Routes,
Geosyntec Consultants
Figure 4,A. and 48, Interim Filling Plan, Geosyntec Consultants
Figure 5, Leak Detection System Sumps for Cell 4.A' and 48, Geosyntec
Consultants
Figure 64 and 68, Leak Detection Sump Operating Elevations, Geosyntec
Consultants
Figure 7, Hydraulic Profile Schematic
Cell4A and Cell48 Freeboard Calculations
Table lA, Calculated Action leakage Rates for Various Head Conditions,
Cell4,A., White Mesa Mill, Blanding, Utah, Geosyntec Consultants
Table 18, Calculated Action leakage Rates for Various Head Conditions,
Cell48, White Mesa Mill, Blanding, Utah, Geosyntec Consultants
Whitc Mcsa Mill Tailings Management System and Discharge Minimization
Technology (DMT) Monitoring Plan.
4)
s)
7)
8)
e)
NlCell 4BUanuary 2l Submittals and revisions BAT O&lvl\Cell 44, and 48 O M Plan Rev 2.2 clean.docN:\Cell
4BUanuary 2l Submittals and revisions BAT O&M\Cell 4,4, and 48 O M Plan Rev 2.2 clean.doc
Page 17
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deasyntec Consuftants Table 1A
Calculated Action Leakage Rates for Varlous Head Conditions
Cell 4h, White Mesa Mifl
Blandin* Utah
Head Abovs linsr
Syrtem {fsstl
Cafculetad Actlon lcefiage Rate
(gallonslacreldeyl
5 222,94
10 3L4.0
15 3fi4.58
20 444-08
25 4ps,5
30 543,88
35 587.5
37 fifi4.fi
Geosyntec Consultants Tabfe 18
Calculated Action Leakage Rates for Various Head Conditions
Cell 48, White Mesa Mill
Blanding, Utah
Head Above Llner Syrtem
(feetf
Calculated Action lerkage Rate
{gallon slaereldaVl
5 aLL.4
10 3L7.4
15 359,9
20 422,7
25 475,6
30 528.4
35 570,0
37 581,2