ML19345G450

Annual Financial Rept 1980

ML19345G450
Person / Time
Site:	Davis Besse
Issue date:	02/23/1981
From:	Ginn R, Miller R, Williams H CLEVELAND ELECTRIC ILLUMINATING CO.
To:
Shared Package
ML19345G447	List: ML19345G446 ML19345G450
References
NUDOCS 8104070266
Download: ML19345G450 (47)

Text

4 chen and associates CONSULTING CEOTECHNICAL ENGINEERS M SOUTM Zuke STREf f

• DENVEA,COLOAADO80223

• 3CDF4+7105 O

O CONSTRUCIIQ1 REPOfE FOR ENLARGEMENT Op TAILI'KE DISPOSAL RESERVOIR BEAR CREEK URANIUM COMPMW COtNERSE COUN1"I, WYCMING O

!O O

O o

Prepared for:

g BEAR CREEK URANILM COMPANY P.O. BOX 2654

. CASPER, WYOMING 82602 Attention: Mr. Robert Medlock Job No. 6213W Febr"ary 2, 1981 m OFFICES: CASPER

• COLORADO SPRINGS e GLENWOOD SPmHGS o SALT LAKE CITY

[]{P CJ f/04'ofoh'd

O O-TABLE OF O2TmfrS O

INff000CTIQ4 1 DESIGN 1 O ca4srRocriai 2 General 2 Equipment 3 g Procedures 3 Problers and Their Resolution 4 MAIN DN4 E24IARGD1ENT 5

"^S'N R * * ' b O

QUALITY ASSURANCE 7

SUMMARY

8 O PIG. l - curoFF TRENCH PIOFIIE ido DAM SECTION FIG. 2 - ILCATION OF PINEABILITY 'IESPS Ato 'IESf HOLES, INCREMENTAL AREA

~ TABIE I - SUP9ERY OF PEIDEABILITY TESTS O

O O

~

_______________J

D INDODUCTION The addition to the original tailing dam was necessary to 3 It also increased provide storage volune for the Iw flood series.

the storage capacity for mill tailings. The original dam was conpleted in 1977, and a construction report, our Job No. 5329W, was J prepared in accordance with NRC requirements.

The enlargement consisted of raising the dam embankment height approximately 10 feet and its length proportionately to tie into the J natural topography. On the right abutment, a long, wing dam was required. Interceptor ditches divert upstream drainage around the inpoundment area and discharge it downstrean of the seepage control D embankment. Areas in the basin were treated to reduce their permeability. Our firm participated in the design and construction control of the enlargement.

)

DESIG4 Design plans and specifications for the enlargement were J prepared by Rocky Mountain Energy Conpany. The geotechnical aspects of the enlargement were provided by Chen and Associates, Inc. under the following reports:

D (1) Job No.16,600 dated August 8,1979 and April 8,1980, Stability Analysis.

i (2) Job No. 17,566, Analysis of Tailing Consolidation, September 24,

] 1979 and April 17, 1980.-

i

(3) . Job No. 19,678B, Report of Investigation for Pervious Zones, Incremental Area of Enlarged Impoundment, January 22, 1980.

P j

L

e (4) Job No. 6216W, reports cc construction, March 5,1980 through Septenter 22, 1980.

'the design included a steepened upper slope to a crest elevation l of 5160 feet. 'Ihe side slopes were designed at 1.5:1 upstrean and 2:1 dwnstream to allow raising the embanknent without extending J

excessively over the existing slopes. The increased beight required extension of the urbankment approximately 200 feet cn the lef t abutment and a 1,000-foot long wing dan paralleling the inpoundment a

basin cm the right side. A key trench or cutoff to bedrock was tied into the existing cutoff trench and continued along the main embank-ment and wing dam extensions. Increasing the storage volume to accormodate the probable maxinun flood series eliminated the requirenunt for a spillway.

COrJSTRUCTIOi General: Construction was performed by Bear Creek Uranium Mine personnel. Claystone overburden frcrn the B-1 pit was stockpile.i beginning in February 1980. Periodic testing was pcrformed by our representative during the stockpiling operation. The material consisted essentially of a plastic claystone with some siltstone and sandstone. During <xnstruction, additional borrcw was obtained frcxn

,the B-1 pit. Results of testing of these materials are included in the daily reports provided dering construction. The naterial was similar to the core zone material in the existing embankment and is imperviot s when cortpacted.

3 Equiprent: The equipnent utilized varied depending on the avail-g ability and stage of construction. The maxinun number of pieces used is listed below:

No. Description I

g 5 Wheel Tractor Scraper, Caterpillar 633-D 1 D-9 Caterpillar Dozer 1 Northwest Backhoe, SSDil

] 1 Motor patrol, Caterpillar 16-G 1 Sheepsfoot compactor, self-propelled, Caterpillar 825 g 1 Water wagon, 11,000 gallons Procedures: Bear Creek conducted a 1-shift operation throughout nost h of the period of construction. During placement and conpacticn of fill, our field representatives wre on the site. Daily and weekly reports have been submitted as the work progressed.

3 The sequence of cperations consisted of stripping the upper materials to provide a suitable surface for placement of new fill.

The fill material was taken frcxn the stockpiles and brought to the embankment and blanket areas with high speed scrapers. Pre-wetting in the stockpiles was utilized. Materials were spread in thin lifts, wetted to the proper moisture content, spread by the motor patrols and g conpacted to the required density by the sheepsfoot compactor.

Density tests were obtained during the process at depths 6 to 12 inches below the working grade. Both moisture and density were used as controls in placement and ccxnpacticn of the fill. Record 3

) .

r D , <. sanples were obtained of the material to confirm that it was suitable.

Results of those tests are also presented in our daily report.

Problems and their Resolution: No major problems were encountered during the construction.

During construction of the extended cutoff at Sta.18+00, it O

became apparent the existing 24-inch CMP culvert would have to be relocated. Excavation of the pipe showed it to be silted up. It was decided to abandon the culvert and the northeast diversion ditch, thus O

allowing surface drainage from part of that area to flow directly into the reservoir. The area served by the pipe was decreased by extending the southwest channel. Since the ditch is assumed to fail during the O

NHC PMF series, this does not change the capacity requirements. A letter requesting the change was sent to the Wyoming State Engineer by Rocky Mountain Energy Company on October 8, 1980.

O .

Moisture control in the fill material required close attention. .

Sometimes, areas were scarified and remoistened in order to meet the specified moisture requirenents.

O Extending the piezmeters was somewhat difficult. Piezameter No. I was saved and extended, and No. 3 was lost due to filling in with loose soil. This piezameter was replaced.

O Plastic borrow material was exhausted frm the stockpiles during construction, and additional inpervious material had to be located.

This was obtained frm the claystone overburden within the B-1 pit.

O The material selected was tested, met specifications and stockpiled for use in the embankment and blanket area.

O O

,, . _ _ _ w ,

e The cutoff trench cn the left abutment did not encounter tulrock between Stations 50 and 1+50. At Statico 1+00, the ground elevation is 5154, so the embankment height is only about 6 feet. The cutoff trench was excavated to elevation 5137 feet. Elevation 5137 is below the depth of the existing cutoff trench at the transition from the old to new cutoff trench. This depth is about 3 times the embankment height and was deemed sufficient considering the hydrostatic head at this point.

S4  !

{,

MAIN DAM D4LARGEMDR

(

Construction of the enlargement of the main section of the dam J

involved moving the tailing discharge lines and stripping the beached sand from the upstream face of the existing embankment. This was necessary to allow removal of the existing embankment material to form benches upon which to place the new material. On July 11, renmal of the material from the crest down to the claystone core began.

Excavation for the cutoff trench cm the left abutment extended down through the existing core and to a maxinun depth of about 17 feet, or into the sandstone and siltstone bedrock. A sketch of the as-constructed profile is shown on Fig. 1. On the right abutment, J

bedrock was fairly shallow, and the transition was made at about Station 19+00 fran the old cutoff into'the wing dam which extends southeastward. Bedrock was shallow, and a ncminal cutoff varying from m

about 12 feet deep at the transition, Staticn 19+00, to about 3 feet beyond Station 22+00 was constructed.

e Prior to placirg rew 1ill, tre existing raterial or the ratural soils were scarified and :cistened, ne rew erca-Jcent raterial c:r.sisted entirely of irpervious, plastic claystcre with sore saMstcre. Cnedc sarples wre taken as tre raterial was placed ard

, have teen reported. Ccrpacticn and testing then tcch. place. idl cf tre raterial was cacracted to the specified density at tre reg; ired noisture content. Placecent of fill crntinued into the smd vak in Septecter 1980.

g) ,

l l S re care was required in the transition area betwen the existire dan ard the southeast wirg dan. In this area, the existing i

~J -

24-inch culvert occurs, as well as tailire discharge lines, ne tailing discharge lires were tecporarily buried in tre trench, and transitico slcpes of 5:1 were pecnided for the i pervious raterial *w a, interface with tre existirg trencn. Af ter tre ertarJcent was to design height at about Statico 20, the lines were relocated ard the tenporary trencn backfilled.

EASIN 'IPEAWl.T Initial work at t's site began with treatrent of the irmmntal area to prcwide an irpervious basin. Previous studies showed fccr a

areas that reeded treat:ent. 'Itese areas are sto.n cn Fig. 2. Tre treatrent included reracnire tre vegetaticn aM tcpsoil, insp3ctire tre area to be treated aM then recovirg an ailiticnal 2 incres *w 3 feet of natural soils. 'Ite exposed sabgrade was scarified, oistened ard ccrpacted to 98% standard Proctor density. The i..pervices claystcre was then placed in lifts and cccpacted. In scre areas, the excavated

_7_

coils wre m'.xed with the claystone frera the stockpile and replaced in 3

cortpacted ;if ts.

To confirm the effectiveness of the treated area, shallow roles wre hand augered at a depth of 1 1/2 feet into the clay liner and

• 4-inch diameter plastic pipe inserted in the holes. An q)en end permeability test was then performed. The results of these tests are shown on Table I. The tests show the treatment was effective in h reducing the permeability to 10-6 on./sec. or less.

t QUALITY ASSURANCE

)

During placement of mbankent or basin material, we had a full f tim representative on the site. A field soils laboratory was also established on the site to allow rapid processing of mils. A Troxler

, 3411-B nuclear moisture-density gauge was used as well as a standard sand cone for dieck testing.

Quality assurance begart in February when plastic claystone overburden material was being stockpiled. Results of those tests were reported in our letter of March 5, 1980. During placement of the inpervious soils, additional check tests were made. These were reported periodically during the course of construction. Continual visual classification was made during the placenwnt and cmpaction operations. Thirty-one sa"ples of the stockpiled nuterial were taken and tested during February 1980. During the course of construction, 21 additional samples were tested for standard properties.

For density and moisture control of the dan embankment,189

> tests were performed. Of these, a total of 13% failed to meet the

g specification requirements for noisture and density. Of these, about 5% failed due to low densities, 4% due to low moisture content, and 4%

4 due to both noisture and density being outside of specifications.

Areas where failing tests occurred were scarified, the noisture content a3 justed and reempacted. Subsequent testing indicated e satisfactory compactico for all of these zones.

In the basin blanket area, a total of 177 density tests were taken. Of these, approximately 19% did not meet specification requirements on first testing. Of the failing tests, 2% failed due to

('

low densities,14% due to low or high noisture content and 3% due to i

both noisture and density being unsatisfactory. All of these failing

'J '

areas were reworked, and substquent testing indicated satisfactory

, noisture and cmpac'. ion. Tne average density was close to 100% of standard Proctor density with noisture content within 2.5% of optimum.

SLM4ARY The (x>nstruction of the embankment enlargement and lining of the incremental area in the basin were cmpleted without any major problems. There is no difficulty meeting (xxnpaction requiretmnts with the material and equipnent beirg used. The cmpleted work has resulted in an increased embankment height and basin area that neets design intent an4 projg,ct a specifications.

}# CIIEp}s c

7 sTef,t N CHai AND ASSOCIATES, INC.

1:

o A\

?) [ By . O rw' m b. /,-. > p/t / Richard C. Hepworth, P.E.

IG/bn 9 '

cc: Rocky Itunta h' Energy Cmpany Attention: Mr. Bob Coppin

L. {

-2+00 -1400 0 1+o0 2+00 5180 V N d Scale:

r \g N Vertical l' Horizontal N

5160 N fr N

. =,

,~ K

• m.,

5140 fr

. po u.

! 16+00 17+00 18+00 19+00 20+o0 21+00 i S Actual Escavation for

< Cutoff Trench ri 4

/ --

4 l-Preratsee t slee t

-sl o ogg

-/e w p ,

. ':; . M t Wi 1 F-2 . TM j

-5150 Prerelse ,,

g Embankment s' s' s u

J OEE5'l.ls'

' ... . a '

e. , _. t u .,n 4

m ,.. - . . _ , , . .

1 I

i

=20' 1"=100' f

OFILE OF Ctff0FF TRENCH EXCAVATloN 22+co 23+00 24+00 25+00 26+00 27+00 28+00 29+o0 5180 ginal Ground Crest El.=5160 Line j - - -

5160

."~ ~ ~ ~ - *_ _ _ _ _

~

--./ ,

p_ f -

\ s

\ Maximum Operating 1 Water Level El.=5 150 5140 Discharge Line term 516 %

JL. . . ..n::

11 f Mew Seach 5150 -

j allings T g 7 w i

?$'$E len Line ' ' ' ' ' ' ' ' s,' ' ~

, ,' , ' h .s' 'O' s. ,

Profile of Catoff Transk l and sum tress amotSan Fig. t

I y- y m.- - c.7 Inr - a

+7 e

b: .

g- ,, - . _ e h .) , .s N 3' . ,

~

{

,, s

? .)

g ,

s , s,TL

' N , 4

..- e'

.i,-~ ,

,. y g

(

- e '/ / - ag,-i to - -4.

W 'o,44 , d' s ay ____._w 3 / = 4. . , e

f. +g, -

f >,t- 8 d "$\TM 1

.g /* '.G 0 ,'.

, u

)e -/ -

- s.1 4, s, -

i j

g.U n-*Ce *

• f ,

f >t

, e - p' -- sie x a i f. N '

EstSTierG Wst 54fE a .

i

~ w s'\. n s \. ' l

./'. \,

\

] 4  % s, , '\ \

' r s/. / '. g .C, y f 5

'(i , ,

'( ( . . , *\ . a - - .

. / 3e , .

/>  ; --4-- s ',

f(- . % jf.rp

• D. .,/. t'

• t,

\

. s,

\.. * <

M,/. ._ $ **

, s. , .

g . . . .

\

s.

=

g.

[* \

\----V '

'Nk ' <

/y +

e s

)

DtSTissG TAlUNGS POmo , ,

eA

• s \

,,' , r. T= Ei *

I^

)

(

' =

') .

.\ /*

{ ,. "

g .

t '

.N_ s e S

\

' , s

, t r iSTt8ef W.:45 DAW .

(,~- s ,

e 4 3.

,, . , .s . - -- -

/

. \

.= ~ _ .

A-s.

• g , . . .*p~-n- -.gn ~. ..- & . e.

- _ _ . . . , j ,' -

N -~  %.

.g . j

.s

. ~

,_ m .

6

,. , , . r.

f

/ ,"

. .'y ;,e /

. ~ .

t g

~

, y

~

p - . . .' ,

'\ A-

, ..--'s  % g

--- e . w ,.

's 'g .

T t

.?

~

.?, )

, / ',

i ,

s-s .T

• 1 4'- .

-> \

'14 -

'-  ?

d z, \-y r 1

, j . , ,._

+ .

\_ l ,/' :. '

',\  %

.\ *\ . . ,

j ,,"\\\

k. $ # '

l

, ') +s g f

\ ..

' . ., i-

, i 1 1, ..

. . .-.s \

1,-l _.t

\ .

L t \

l i s

) i , 'u

) . 'i(s.

,i,

- :.2 ' ;.

s

. . h pl II f /' -

\I #

s  ;, e f '. i 1 ,

. / I 4 j i } l.l [ ! , , ' '. i *

/

' l

';,,'. , s

/ ,

, ,j , , '

s s s

>t7

~ . <

l 4 , .t,,g } 3 '

'. ~

i  ! '

'-./* /

N .) t{ '\ u \'h'g s

, [ p .

i", f ,

\% PRE'll0USLY l

,, ^ - - N.l '

) i

// TREATED AREA

( .g\ ; \ \' ,\" \ \3 -

! ,s i4 g

• s -

y 'l'l1 ..

lh, s i l/

(',,

,M)' . ,'(' . . MLyQ .e. l)t)

'~ ^[  ; i AREA TREATED

.bf. ' , , W.w ,.,

, ,s l roR TuiS s , g'R 9 4 5, x ., V j.f .

j j e .7; j PROJECT

- -. . . --~- m ,c l .

]

• I s

% ~< -

I

%., s.1 ,  : . .,wl .\ 1.] ;I

,,n . .- ., . ., ,

N 'x N

'~

.. / * / ,

hs

's van ) 19 ., i;' / / '

%. W.-'

s L  : : , .,ll lr' i

'Rx, 1 \ . -rs u ..

---

pr i1 i ,

\

s . . , . r,. . , /. sf ,,

Yli i.

^

., i

\

>  ?

s g' -- 1 m

\'

s

- -? '*

1m-se

\ ,

\

s. , ,

/ .. _ . .__ _

1

~ s,

,a . . . ,

>"~

se - se , -

7

~.  ; -

.er

', ~

t- I

. . , _ . , . ~.

A N

/.- y ; ...,.. e in-s e

.e /,I-a - s

-77 'u -

V. ,, ,-

A

,s.

- NOTE: INCREMENTAL AREA SHADED N

vn-o4 m ,

s -, , , -

,g*% N -!..  ; i 1' O Permeability Test Ng ..

' ' ~'

' E[ i June-July 1980 K 5% < > :]f '

• 3  !' ,

\

to E! '<' Test Holes, Nov.-Dec. 1979

.s \ ,. N;i' h 7s wi- .-

m'~--5 u$'3 .m. '

" t'V

/  ;

m . *. 4oo*

~

. . . .- . k , ). . . ~ . . 5.'s Tw so

%j..s.. -

og . . . ,

y' o soo' I-

's .

.\

• x vx J. 8 N > ~' LOCAT met 3F resutAstLITY vuesa s,

i

,/ AND TEST NDLES, INGLEENTAL MEA 9"J w..x

,~ - -

_. p._,

-- ~ y , \ . x . . -]; j'" ';J

=

[' -,'

f;

.J. -

s v;-

r.

N .,.[

' ( -- ~

,..f

/p '

f. - chese sad associates. inc. J~ , wi w .sss.,a m m e cx e.,s w es e +=== w . amsoes -- _  ;; e " ' *V

• 8

• _

r .," . . at t }. - .

4pg

}  : .y , g&~ j ,_ -

p

% m .M .s-

J O TABLE I SG1 MARY OF PER'4EABILITY TESTS Length of Time Coefficient of Location Depth of Hole for Test Permeability (Ft.) (Hrs ) (cm./sec.)

s Area I -2 1.3 478 2.1 x 10-7 I

-1 1.2 290 1.1 x 10-6

-4 1.1 290 3.5 x 10-7

-3 1.1 500 2.6 x 10-7 O

Area II -5 1.5 504 3.8 x 10-7

-6 1.5 504 6.5 x 10-7 I . -7 1.5 408 4.2 x 10-7

(

i O

Area III -10 1.5 504 3.7 x 10-7

-9 1.5 504 1.0 x 10-6

-8 1.6 504 1.5 x 10-7 O

TOPE: Tests performed according to USBR "open end permeability test",

4" 9 cased hole.

O O

O loo"..".)

+ - .

u: