billings & associates, inc
TRANSCRIPT
AQUIFER TESTS -NORTHEAST CORNER AHD EASTERN BOUNDARY
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VolumeUnited Nuclear Corp.Administrative Record0000013502/12/82
BILLINGS & ASSOCIATES, INC.
00000135
AQUIFER TESTS -NORTHEAST CORNER AHD EASTERN BOUNDARY
FOR
we FINING A13D BILLINGCHURCHROCK OPERATION
C H U R C H R O C F , KEV; M E X I C O
DYBILLINGS & ASSOCIATES, INC.
ALDUOUEROUE, NEW MEXICO
«^
w4^-- • uJ^&6^yytftyr^. Dillings^- t _ ' ^ _ * - ^ ^ * ^ r t f t ^ yruary 12, 1982
TABLE OF CONTENTS
i2£££rlp-Lion
Introduction
Section 1: Northeast Corner Zone 3 -Aquifer Test Design
Section 2: Auxiliary ^ell Nest LocationFor Detern.ination of The Extent
' of Contamination In Zone 1 end theTorrivio Sandstone - NortheastCorner^ WC Tailings
Section 3: Eest Borrow Pit Zone 1 -Extraction and Aquifer TestDesign
Appendix A
Appendix B
Appendix C
Appendix D
Appendix E
References Cited
11
LIST OF FIGURES
Figure A
1
. 2
3
4
5
Description
Zone 3 ~ Northeast Tail-ings Area (Drawdown vs. Radius)
Pump Test Layout
Typical ObservdtJion WellLayout
Zone 1 " East Borrow Pit(Drawdown vs. Radius)
Cross-Section of TypicalPumping Well
Cross-Section of TypicalObservation Well
LIST OF APPENDICES
Appendix A
Appendix E
Appendix C
Appendix D
Appendix E
Well ConstructionSpecifications
Well Development Procedures
Well Construction MaterialsSpecifications Supplied byUI3C
Pump Test Materials Suppliedby UI3C
UNC Participation
LIST OF PLATES
XlAtfLJL
1
E^CJ-Jp.tlPB
Well Locations
INTRODUCTION
This report details additional aquifer -..-sting and
drilling of the groundwater decontanination systems required
at the United nuclear Corp. (UMC) Churchrock Mill Site. The
report is divided into three sections. The first section
deals with the contamination existing in Zone 3 in the
northeast corner of the tailings area. The second section
deals with the contamination occurring in Zone 1 and the*
Torrivio Sandstone^ in the northeast corner of the tailings
area* Finally? the third section describes the extraction
syster. needed for the Zone 1 contamination on the east side
of the Borrow Pits. Contaminationy as a term used in this
report, refers solely to that related to tailings operation
and not to "natural contamination.tt
SECTION 1:
NORTHEAST CORHERZONE 3 - AQUIFER TEST DESIGN
INTRODUCTION
Previous water quality investigations (SAIr 1981 and BAIr
^982) / have identified groundwater contamination existing to
"the northeast of the United Nuclear Corp. (UNO tailings
area. The dispersion of the contamination appears to be in a
northeast flowpath.
It is UNC's intent that the contamination in this area be
removed^ Thereforor an aquifer test is proposed in order to
establish aquifer parameters in this area- These aquifer
parameters will then be used in the development and
installation of a permanent decontamination system.
: .'*';,.•••'. i;*. :' r. ' .,,1,:..'"'' •,.;'. ,1-S
A Q U I F E R TEST
The aquifer test will consist of one pumping well and
three observation wells (See Plate tl for well locations).
However/ other wells in the area will be periodically
monitored during the test. Appendix A describe? the
procedure of and presents the specifications for well
construction. Appendix B presents the well development
procedures- Appendix C lists the estimated material
specifications for veil construction. Presently available
data indicate that the construction and development^of these
wells should be completed in such a manner that they may be
p&rfc of the permanent decontamination system*
A preliminary discharge range of 0.9 gal./min. to 1 4 . 5
gal./min. for a minimum test pumping time of 10 days was
established for the aquifer test. This discharge range and
minimum test time allows for a radius of influence of at
least 150 feet. The pumping time, discharges^ drawdowns and
radii of influences were computed from the solution of the
Theis equation ( 1 9 3 5 ) . The Theis equation in its simplest
foryr. is (Johnson Division? UOP Inc., 1980) :
where s
s =-
0 -
T ^
W ( u )
s == ( 1 1 4 . 6 x Q/T) x W ( u )
drawdown, in ft. at any point in the vicinity of a
well discharging at a constant rat
pumping rate/ in gal./min.
transrr.issivity of the aquifer^ in gal./day/ft*
the well function and is approximated by the
equation below:
7 3W ( u ) ^ -0.5772 - log. u+u - u / ( 2 x 2 ! ) + u / ( 3 x 3 ! )e
u 4 / ( 4 x 4 ! ) . . .
In this express ion,
u = 1.87 x r2 x S/(Txt)
where?
r =
s ^
T ==
t ^
distance^ in ft-y from the center of the pumped
well to a point where drawdown is measured,
coefficient of storage, dimensionless
transmissivity? in gal./day/ft.
time since pumping Btartedy in days^
If the transmissivity and storage coefficient are known,
values for these and other terms can be substituted in the
formula to obtain a desired unknown.
«
For example, using a transmissivity equal to 822.9
gal./day/ft* and a storage coefficient of 0 .015 (typical Zone
3 aquifer parameters in the 400 well series, SAI, 1 9 8 1 ) ,
various values of drawdown may be computed for correspondingrf-"^-
values of pumping times and distances from the pumping well
(radi i )<
Using a radius of 0.1 ft. (approximate radius of pump),
and a limiting drawdown value of 50 feet (average thickness
of Zone 3 is 58 feet as deter^i^e^ Jf^gJp site^eophysic&l
logs? leaving 8 feet to accomodate pump height), a maximum
purr.ping rate of 22 gal./min. was detern.ined for a 10 day
pumping tirr.e. A pumping time of 10 days was chosen because
it yielded a sufficient radius of influence for the purposes
of the test* Once the discharge of 2 2 * 0 gal./rr.in. had been
determined, drawdowns at various distances from the pumping
well were then computed. These drawdowns are presented
graphically on Figure <1 .
Using the s$me procedure for the solution of. the Theis
equation as that presented above, the second curve an Figure
?1 was generated for a transmissivty value of 35-2
gal./day/ft, and a coefficient of storage of 0 . 0 1 5 , This
5
FiQUre Sl
ZONE 3 - NORTHERST TRILINGS
T I M E -. 10 CRTS
bc-
•X.»0Q»(X(E:
a
300
1 » (0- 22 (GRLJMIt^l
RND T » 9Z2.9 (GRL.^&flT/FT.U
• « tQ « 1.1 [GOL. /MIN.1 SNO
T - 3S.2 EGRL. /DPT/FT . ! )
JL \ 1 i ? i H I I I M H
DESTFtMCE FRO^I PUMPING VFI.L t fT . l
100 IODQ
BILLINGS & PSSOCIRTES
PROJECT 9 1 2
DPTE 920210
!NC
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curve represents the drawdowns at various distances from the
pumped well for a discharge of 1*1 gal*/min. This discharge
produces the upper value of drawdown for a 10 day test. The
transmissivity value of 35.2 gal./day/ffc. was determined from
data obtained from a slug test on well TWQ-124 (SAI, 1 9 8 0 ) .
k
These calculations serve only as guidelines in enabling a
more accurate design of the aquifer test. The final
discharge rate and pumping fcin-.e for the aquifer test will be
determined in the field. The discharge rate will be set by
conducting a step drawdown test prior to the initialization
of the aquifer test- For the step drawdown test and the
aquifer test/ the measurement of discharge will be
accomplished by the use of a flowmeter. See Appendix C for
the needed testing materials* See Figures S2 and S3 for the
testing arrangement of both the pumping well and the
observation wells, respectively* Water level measurements
will be obtained by pressure transducers for wells 600, 517,
518, 124 and 505-B, and by water marker for wells TWO-123,
125, 126 and 127. See Appendix E for UKC participation.
Every 24 hours after the start of the test, water samples
from the pumping well will be taken. These samples will be
analyzed for the following parameters:
f» pHe ECft S04« TDSQ N03
7
2" Flowmeter
To TailingsGate Value
(Not to Scale)
Figure < 2: Pump Test Layout
Cable ClampTo Pumping Well
Pressure Transducer
(Not to Scale)
Fi9ure <3: Typical Observation Well Layout
9
CONCLUSIONS
Groundwater contamination has been identified in Zone 3
near the northeast corner of UNC's tailings. This
'contamination is to be removed by a permanent deconfcamination
system. In order to establish the size of the needed
decontamination system, the parameters of the contaminated
aquifer must be determined.
Therefore, an aquifer test is proposed in order to
establish the transmissivity and storage coefficient of the
contaminated aquifer. Once these aquifer parameters are
determined, a permanent system to decontaminate the aquifer
will be designed and constructed.
10
SECTION 2
AUXILLARY WELL NEST LOCATION FORDETERMINATION OP THE EXTENT OF
CONTAMINATION IN ZONE 1 ANDTHE TORRIVIO SANDSTONE -
NORTHEAST CORNER, UNC TAILINGS. AREA
11
INTRODUCTION
Water quality data from Well 450-A and 505-A indicate
contamination in Zone 1 in this area. If Zone 1 is
.contaminated in this area, the plume of contamination appears
to be small in size. For instance? other wells screened in
Zone 1 such as 448 and TWQ-120^ show no signs of
contamination.
Water quality data from Well 449 and 505-C suggests C
contamination in the Torrivio sandstone in this area.
CONCLUSION
Two pumping wells similar in design and completion to
Well 600 should be drilled at the locations shown on Plate
^1. Should contamination be identified in this area, in Zone
1 and the Torrivio sandstone, then these two wells should
serve as extraction wells for the removal of the
contamination. See Appendix A and C for a complete
description of well construction procedures and
specifications.
Upon completion of the ^constJUctxpn of the well, the
development process should begin. For a detailed reference
on well development procedures, see Appendix B*
12
Should the water samples indicate contamination in these
zones, aquifer tests using these wells should be implemented.
These aquifer tests should be carried out in conjunction with
previously identified observation wells exhibiting
contamination*
L
Should no indication of contair Inafcion be found from these
new veils, then the extraction system will progress, pssuming-^ - - - „ . - - _ . - , .," • • '•«"*
contamination in Zone 3 only.
»-0 -•^
C " ^
< ^J^&J
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13
SECTION 3:
EAST BORROW PITZONE 1 ~ EXTRACTION ANDAQUIFER TEST DESIGN
14
Water quality data (BAI» 1982) in the area east of the
borrow pits have indicated groundwater contamination in Zone
i. It is proposed that this problem of contamination be
solved by a groundwater extraction system. Previous pumping
( S A I , 1980) in this area has shown that a pump system could
work in the extraction of the contamination. Based on this
previous pumping, two pumping wells with locations shown on
Plate *1 are needed.
Using the transmissivity of 200.5 gal./day/ft, and the
forage coefficient of 0.000105 obtained from Well 304 during
the Well 303 pump test ( S A I , 1 9 8 0 ) , initial discharges/
drawdowns and pumping times were computed for the proposed
Cast Borrow Pit aquifer test. Using a technique for the
solution of the Theis equation, as presented in Section 1 , a
ficwrate of 3 . 3 gal./min. for a minimum pumping time of 10
days was determined. According to the calculation^ this
flowrate will produce a drawdown of 36 feet in the pumping
well (See Figure t 4 ) . The average thckness of Zone 1 as
determined by the geophysical logs is 44 feet. Therefore, a
total of 8 feet is left to accommodate the pump height.
Again, these calculations serve only as guidelines and the
parameters obtained from these calculations will be adjusted/
if necessary? during the field program*
15
'Figure ?4
ZONE 1 " ERST BORROW PIT
TIME « 50 ORYS
(—
1DDO
BILLINGS & RSSOCIRTES,
PROJECT 9 1 2
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i «> 4 (GRL./MIN.l
INC
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The two wells, 603 and 6 0 4 , will be drilled by reaming
Wells 307 and 303, respectively. These wells are being
reamed (redrilled) and reconstructed in order to increase the
efficiency of the well. The diameter obtained by reaming
-(redrilling) will be the same diameter or larger than that of
the original well. The construction and development of Wells
603 and 604 will proceed according to Appendices A and B ,5 '
respectively, except for the reaming process.
iL.
Prior to the initialization of the aquifer test, a step ""
drawdown test will be run in order for a permanent discharge
to be set. See Figure f2 for the pump test layout. Once the
permanent discharge rate has been established, the aquifer
test should proceed in a manner similar to the start-up of
the 400 series extraction system ( S A I , 1 9 8 1 ) *
The first well ( 6 0 3 ) , should begin pumping and when its
radius of influence has reached the halfway mark to the
second well ( 6 0 4 ) , the second well should begin pumping. The
radius of influence for both pumping wells will be determined
by measuring the drawdown occurring at wells 313, 311, 310,
303, 301, 515-A and 516-A. Drawdown in the observation wells
will be measured by a combination of pressure transducers and
watermarkers* A field decision after 10 pumping days will be
ruade as to whether to continue pumping or to begin recovery.
17
The data obtained from the pump wells an^ the observation
wells will be used in analysis techniques to evaluate the
aquifer parameters. These parameters will be used to
ascertain whether or not more wells are needed for the
-permanent extraction system.
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18
APPENDIX A
WELL CONSTRUCTION SPECIFICATIONS
19
Pumping Wglls
The pumping wells ( 6 0 0 , 601, 602, 6 0 3 , and 604) will be
rotary drilled, using Revert as the drillig fluid, to a
diameter of 12 1/4" and to elevation depths of approximately
6857, 6803, 6 9 0 8 , 6871 and 6888 feet above mean sea level,
respectfully. Cuttings will be obtained and recorded at 5
ft. intervals. When the total depth is being approached, the
drilling may be stopped short or deeper than the predicated
final depth, depending upon the cuttings obtained. By doing
this, the possibility of interformational contact due to over
drilling will be greatly lessened* The wells will then be
geophysically logged in order to verify the correct depth of
the target formation. The following parameters will be
obtained from the geophysical log:
• Resistance« Gamma» Spontaneous Potential*
Once the target formations have been identified, the
construction of the wells will proceed according to the
followng procedure (See Figure ( 5 ) :
6 The borehole will, if necessary, be backfilleowith bentonite pellets until a seal isobtained at the bottom of the targetformation.
« The casing \ ill then be lowered into the welluntil the screen is opposite the formation.
• The sand pack will then be placed in theennulys opposite the screen
9 A bentonite seal of approximately 15 feet willthen be placed on top of the sand pack.
20
•\ >^ x' ^~T\"^6" Sch 40
Blank PVC
12 1 /4" Annulus
" Sch 40
PVC Slotted Screen
6 " Sch 40
PVC End Cap
Benfconite Sealr-
20 Sc^nd Pack
Bentonite Seal
(Not to Scale)
Figure <5; Cross-Section of Typical Pumping Well
21
• A bentonite cement slurry will then beinjected into the annul us froni the topbentonite seal up to the ground surface.
Observation Wells:
The observation wells will be rotary drilled, using
Revert as the drilling fluid, to a diameter of 5 inches and
to the elevation depths presented in the following table:
K^JLl, Npx.
521522
Elevation Depth(£t i above miSil.J.
68576859
These elevation depths intersect Zone 2 by apprcxinicitely
2 feet. The wells will then be geophysically logged in order
to verify the depth of the target formation. The parameters
obtained from the geophysical log will be:
• Resistance• Gamma« Spontaneous Potential,
The construction of the observation wells will proceed in
the same manner as the pumping wells except for the size of
the well (See Figure t 6 ) .
22
^ry x' >/2" Sch 40Blank PVC
5" Annulus
»2" Sch 40^VC Slotted Screen
2" Sch 40PVC Fnd Cap
Bentonite-Cement Slurry
Bentonite Sealr '
10-20 Sand Pack
Bentonite Seal
(Not to Scale)
Figure *6: Cross-Section of TypicalObservation Well
23
APPENDIX B
WELL DEVELOPMENT PROCEDURES
24
It is the purpose of well development to clean the well
bore and the immediate area around it of as much drilling mud
and fluid/ fine grained sediment and any other foreignvmaterial as possible. One of the best methods for doing this
is to pump or otherwise produce water from the water bearing, - . - - - - -
zone in order to flush the foreign fluids and sediments.
All of the pumping wells will be developed by: _
1. Circulating for approximately one-half hour with new,clean pit water before setting the casing.
2. Blowing the well dry by sir-lifting, using a drill steminside the well casing* In this procedure? the bottomof the drill stem will be periodically raised at 5 f t .intervals until the entire thickness of the formationhas been blown. If the water is clear, this procedurewill stop. If the water is not clear, the procedurewill begin again.
When the well development process is completed? the water
level in the well will then be allowed to stabilize.
Periodic water levels (approximately every 8 hours) will then
be taken until a decision is reached concerr-ing the static
water level*
The observation wells will be developed by:
1. Circulating for approy-imately one-half hour with usedpit water before setting the casing.
2. Hand bailing the well after the casing is set. Thebailing will discontinue, which terminates thedevelopment of the well when the water becomes clearo
25
The well will then be allowed to stabilize while periodic
water levels are obtained. A decision will be reached as to
when the water level in the well has reached its static
position.
26
APPENDIX C
WELL CONSTRUCTION MATERIALS SPECIFICATIONSSUPPLIED BY UNC
27
Zone 3—- Northeast Corner
Mai.erj.a.l
2" PVC Screen (Sch 40, 0.035 in slot)
2" PVC-Solid (Sch 40, bell end)b-
Bentonite Pellets (1/2" diameter? 50? buckets)
Sand (10-20 grade)
Cement (1 bag & 6 gal. H20 =1 cu. ft.. Type ID
Bentonite (loose bagged)
2" PVC End Caps (Sch 40 solid)
2" PVC slip couplings (Sch 40, long type)
PVC primer (Purple HiEtch)
PVC Glue (Clear Fastset, 1 qt. cans)
6" PVC Screen (Sch 40 , 0 .035 in slot)
6" PVC Slip Couplings (Sch 4 0 r long type)
6" PVC-Soli'd (Sch 40, Bell end)
6" PVC End Caps (Sch 40, Solid)
3 /4 " screws
3/4" Hand Drill
28
100 feet
320 feet
15 buckets
40 cu. ft.
120 bags.
11 cu. ft.
3
15
3 cans
3 nans
50 feet
8
160 feet
2
60
1
ZQJUS.J. and TO^fiviQ - Northeast Corner
Material
3entonite Pellets <1 /2 " diameter, 50fi buckets)
•Quantity12 buckets
Sand (10-20 grade) 40 cu. ft.
Cement (1 bag & 6 gal. H20 = 1 cu. f t . , Type ID 100 bags
Bentonite (loose bagged) 10 cu* ft.
6" PVC Screen (Sch 40, 0 .035 in slot)
6" PVC Slip Couplings (Sch 40, Long Type)
6" PVC-Solid (Sch 40, Bell End)
6" PVC End Caps (Sch 40, Solid)
3 / 4 * 1 Screws
3 /4" Hand Drill
2 li£_l ,-.,.,Eflgt Borrow ,£it£
90 feet
10
310 feet
3
60
1
HfiLL£JLicll
Bentonite Pellets ( 1 / 2 1 1 diameter, 50^ buckets)
Sand (10-20 grade)
Cement (1 bag & 6 gal. H20 = 1 cu. ft.. Type II)
Bentonite (loose bagged)
6" PVC Screen (Sch 40, 0.035 in slot)
6" PVC-Solid (Sch 40, Bell End)
6" PVC End Caps (Sch 40, Solid)
PVC Primer (Purple HiEtch)
PVC Glue (Clear Fa'stset, 1 qt* cans)/
3/4" Screws
3/4" Drill
29
Q ,nfciJ.y
12 buckets
40 cu. ft.
65 bags
10 cu. f t -
90 feet
200 feet
3
2 cans
2 cans
60
1
APPENDIX D
PUMP TEST MATERIALS SUPPLIED BY UNC
30
Ha.terigJ-Submersible Pumps- 1 to 30 ^al/min at 100-250 ft. head
Pressure Transducers- 0-100 p . s . i . , 400 ft. cable on each
Terminal Indicator (with at least 6 ports
Recharger(AC and DC)
Power Source (Generator or Permanent)" 110V and 220V supply
Flexible PEC Tubing and Necessary Couplings
1/4" Stee:. Cable and Reel
Gate Values- 2"
90 degree Elbow" 2"
Kipples- 2" diameter x 6 " length
Flowmeter- 2" Intake and Outake- 1*-50 g . p . m .~ Instantaneous and totalizer
Quick Connect- 2" diameter
Discharge Hose (Quick Connect)- 2" diameter " 1500 feet total length
Barrel" 55 gallon
31
^UAIlUj
3
6
2
1 r ——
1
600 feet
600 feet
9
15
3
3
Support Blocks- approx. 3 feet in height
Watermarker(250 ft.)
'Electrical Conductivity Meter
Sampling Bottles- 1 liter
Duct Tape- 20 foot roll
Hose Clanps
Rubber Gloves- ( p a i r )
Alarm Clock
APPENDIX E
UMC PARTICIPATION
33
UNC Participation;
1. Drill Rig and crew.
2. Technician (Hours 10 p*m. to 6 a . m . " duration oftesting) »
3» Pump setter.
4. Electrician (Start-Up).
5e Geophysical truck and crew.; -,,.^ -^--^ ...*•.-,-iH .- .;. -s|!-'£-—^e..-! i".t"'B13-^^aB
' • » -;T
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34
REFERENCES CITED
Desgr.ipti.Qn
Theis, C . V . , 1935, "The Relation Between theLowering of the Piezometric Surface and the Rateand Duration of Discharge of a Well UsingGround-Water Storage:" Am. Geophys. Union Trans.,y*- ML^-P* 519-524.
Science Applications, I n c . , 1981, "Ground WaterDischarge Plan", Submitted to United Nuclear Corp.,Unpublished Report.
Billings & Associates, I n c . , 1982, ^Drilling forSeepage Control System; 500 Series: Church rockM i l l " , Submitted to United Nuclear C o r p . ,Unpublished Report*
"Ground Water and Wells", 1980, Johnson Division/UOP, I n c . , Saint Paul, Minnesota.
Science Applications, I n c . , 1980, "Ground WaterDischarge Plan,' 1 Submitted to United Nuclear C o r p . ,Unpublished Report.
35