52294 6



## RECORD O F DECISIO N STOCKPILE D FIN E SLA G ARKANSA S VALLE Y SMELTE R SLA G PIL E CALIFORNI A GULC H SUPERFUN D SIT E (OPERABL E UNI T 3 ) LEADVILLE

, COLORAD O Ma y 199 8 U.S

. Environmenta l Protectio n Agenc y 99 9 18t h Street

, Suit e 50 0 Denver

, Colorad o 8020 2

### Federa l

Program s Corporatio n ASubsxSaiyotCampDmsser&UcKeelnc.

152 6 Col e Boulevard

, Suit e 150 Golden

, Colorad o 8040 1 Tel : 30 3 232-013 1 Fax : 30 3 232-090 4 M a y 15,199 8 Ms

. Rebecc a Thoma s U.S

. Environmental Protectio n Agenc y Regio n VIII

, Mai l Cod e (8EPR-SR ) 99 9 18t h Street

, Suit e 50 0 Denver

, C O 80202-246 6 Project : RA C Regio n VIII

, Contract No

. 68-W5-002 2 Wor k Assignmen t No.014-RSBD-082 9 DCN : 3280-014-RT-DECD-0265 6 Subject : Fina l Recor d o f Decisio n fo r Stockpile d Fin e Slag

, Arkansa s Valle y Smelte r Sla g Pile

, Californi a Gulc h Superfim d Sit e (OU3)

, Leadvill e Colorado

. Dea r Ms

. Thomas : Enclose d pleas e fin d 1 0 copie s o f th e Ma y 199 8 Fina l Recor d O f Decisio n fo r Stockpile d Fin e Slag

, Arkansa s Valle y Smelte r Sla g Pile

, Operabl e Uni t 3 o f th e Californi a Gulc h Superfun d Site

, Leadvill e Colorado

. Th e signe d signatur e pag e ha s bee n incorporate d int o thes e copies

. I f yo u hav e an y question s o r comment s regardin g thi s documen t pleas e fee l fre e t o call

. Sincerely

, C O M FEDERA L PROGRAM S CORPORATIO N

K e n Blac k Projec t Manage r Enclosure s J i m Moor e Tas k Manage r

cc : DC N

P:\3280-014\FINALROD\RODTRANZDFTOlJ3.wp d

### RECOR D O F DECISIO N 

### STOCKPILE D FIN E SLA G 

### ARKANSA S VALLE Y SMELTE R SLA G PIL E CALIFORNI A GULC H SUPERFUN D SIT E (OPERABL E UNI T 3 ) LEADVILLE

, COLORAD O 

### Th e U.S

. Environmenta l Protectio n Agenc y (EPA)

, wit h th e concurrenc e o f th e Colorad o Department o f Public Healt h an d Environmen t (CDPHE)

, present s thi s Recor d o f Decisio n 

### (ROD ) fo r stockpile d fin e sla g at the Arkansa s Valle y smelte r sla g pil e o f Operabl e Uni t 3 (O U 3 ) withi n the Californi a Gulc h Superfun d Sit e i n Leadville

, Colorado

. The RO D i s base d o n the Administrativ e Recor d fo r Californi a Gulc h OU3

, includin g th e Remedia l Investigation / 

### Feasibilit y Stud y (RI/FS)

, th e Propose d Plan

, an d th e publi c comment s received

. Th e RO D present s a brie f summar y o f th e RI/FS

, actua l an d potentia l risk s t o huma n healt h an d th e environment , and the Selecte d Remedy

. EP A followe d the Comprehensiv e Environmenta l 

### Response

, Compensation

, an d Liabilit y Act

, a s amended
, th e Nationa l Contingenc y Pla n (NCP)

, an d appropriat e guidanc e i n preparatio n o f th e ROD

. Th e thre e purpose s o f th e RO D ar e to : 

### 1

. Certif y tha t th e remed y selectio n process wa s carrie d ou t i n accordanc e wit h th e 

### requirement s o f th e Comprehensiv e Environmenta l Response

, Compensation

, an d Liabilit y Act

, 4 2 U.S.C

. 960 1 e t seq., a s amende d b y th e Superfun d Amendment s an d Reauthorizatio n Ac t (collectively

, CERCLA)

, and
, t o th e exten t practicable
, t h e NCP ; 2

. Outlin e th e engineerin g component s an d remediatio n requirement s o f th e Selecte d Remedy ; an d
3

. Provid e th e publi c wit h a consolidate d sourc e o f informatio n abou t th e history
, 

### characteristics
, and ris k pose d b y th e condition s o f th e stockpile d fin e sla g a t th e 

### Arkansa s Valle y Smelte r sla g pil e o f O U 3 , a s wel l a s a summar y o f th e cleanu p alternatives considered
, thei r evaluation
, th e rational e behin d th e Selecte d 

### Remedy

, and th e agencies consideratio n

of

, and responses to, th e comment s received

. 

### Th e RO D i s typicall y organize d int o th e followin g thre e distinc t sections : 1

. Th e Declaratio n sectio n function s a s a n abstrac t fo r th e ke y informatio n containe d i n th e RO D an d i s th e sectio n o f th e RO D signe d b y th e EP A Actin g Regiona l Administrato r and th e CDPH E Director ; 

### 2

. Th e Decisio n Summar y sectio n provide s a n overvie w o f th e O U 3 characteristics
, th e alternative s evaluated
, an d th e analysi s o f thos e options

. Th e Decisio n 

### Summar y also identifie s th e Selecte d Remed y an d explain s how th e remed y fulfill s statutor y requirements ; an d

Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5I29SP:V32SO-OI4\FINALROD\OU3ROD2.WP

D

### 3

.

Th e Responsivenes s Summar y sectio n addresse s publi c comment s receive d on th e Propose d Plan

, an d othe r informatio n i n th e Administrativ e Record

. However

, sinc e th e EP A di d no t receiv e an y writte n publi c comments, thi s RO D wil l no t contai n a Responsivenes s Summary

.

Recor d o r Decisio n Stockpile d Fin e Sla g (O U 3 ) 5I298P:\3280-OM\FINALROD\OU3ROD2.WP

DDECLARATIO N

Recor d ofDecisio n Stockpile d Fin e Sla g (O U 3 ) 5I298P:\3280-OI4\FINALROD\OU3ROD2.WP

D

### DECLARATIO N

SIT E NAM E AN D LOCATIO N 

### Stockpile d Fin e Sla g Arkansa s Valle y Smelte r Sla g Pil e Californi a Gulch Superfun d Sit e (Operabl e Uni t 3 ) Leadville

, Colorad o STATEMEN T O F BASI S AN D PURPOS E 

### Thi s decisio n documen t present s th e Selecte d Remed y fo r stockpile d fin e sla g a t th e Arkansa s Valle y smelte r sla g pil e o f Operabl e Uni t 3 withi n th e Californi a Gulc h Superfun d Sit e i n 

### Leadville

, Colorado

. EPA

, wit h th e concurrenc e o f CDPHE

, selecte d th e remed y i n accordance wit h CERCL A an d th e NCP

. Not e tha t thi s decisio n addresse s stockpile d fin e sla g only

. Othe r 

### activities require d fo r OU3

, includin g othe r sla g piles
, th e railroa d easement , an d th e railroa d 

### yard
, ar e addresse d under a Consen t Decre e wit h th e Denve r & Ri o Grand e Wester n Railroad

. Thi s decisio n i s base d o n the Administrativ e Recor d fo r the stockpile d fin e sla g a t the Arkansa s Valle y smelte r sla g pil e o f O U 3 withi n th e Californi a Gulc h Superfun d Site

. Th e 

### Administrativ e Recor d (o n microfilm ) an d copies o f ke y document s ar e availabl e fo r revie w a t th e Lake Count y Publi c Library

, locate d a t 111 5 Harriso n Avenue i n Leadville

, Colorado

, an d a t 

### th e Colorad o Mountai n Colleg e Library

, in Leadville

, Colorado

. Th e complet e Administrativ e Recor d ma y als o b e reviewe d a t th e EP A Superfun d Record s Center

, locate d a t 99 9 18t h Street

, 

### 5t h Floor

, Nort h Terrac e i n Denver

, Colorado

. ASSESSMEN T O F TH E SIT E Th e stockpile d fin e sla g a t th e Arkansa s Valle y smelte r sla g pil e doe s no t present a n imminen t o r substantia l endangerment t o publi c health
, welfare

, o r th e environment

. DESCRIPTIO N O F TH E SELECTE D REMED Y 

### Th e Selecte d Remed y i s th e N o Actio n Alternative

, whic h wa s presente d i n th e Fina l Stockpile d 

### Fin e Sla g Feasibilit y Stud y Repor t (FS ) (Terranext

, 1996a)

. Th e F S use d a comparativ e analysi s t o evaluat e severa l alternative s an d identif y th e advantage s an d disadvantage s o f each

. Selectio n o f th e N o Actio n Alternativ e wa s base d o n thi s analysis

. Fo r th e stockpile d fin e slag
, th e 

### Selecte d Remed y leave s th e sla g pile s i n thei r existin g conditio n wit h n o remediation
, engineerin g controls
, lon g ter m maintenance , o r clean u p planned

. Th e Selecte d Remed y i s protectiv e o f huma n healt h an d th e environment , an d i s considere d effectiv e becaus e 1 ) n o 

### complet e huma n o r ecologica l exposur e pathway s wer e identifie d fo r the stockpile d fin e sla g and 2 ) th e potentia l fo r releas e o f metal s i n leachat e fro m th e stockpile d fin e sla g i s minimal

. Th e Selecte d Remed y provide s a contingenc y fo r resourc e utilization
, whic h ma y b e undertake n 

### i n th e futur e i f regiona l marke t deman d exist s fo r th e material

. Resourc e utilizatio n involve s th e Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) ^

. SI2W:\32SCM>I4\FINALROD\OU3ROD2.WP

D J- 1 " 1

### us

e o r reus e o f th e sla g materia l a s a commercia l produc t Du e t o concern s abou t th e potentia l fo r release o f airborn e participate s i f resourc e utilizatio n i s undertaken
, th e EP A ha s determine d 

### tha t resourc e utilizatio n o f th e stockpile d fin e sla g i s onl y appropriat e i f i t i s encapsulate d fo r reuse

. Encapsulatio n ca n includ e th e us e o f fin e sla g i n concret e o r asphal t aggregate ; o r a s roa d 

### base
, backfil l o r othe r constructio n materia l a s lon g a s th e fin e sla g i s chemicall y boun d o r physicall y separate d fro m an y exposure scenari o b y a barrie r consistin g o f anothe r material

. Dus t suppressant s t o contro l paniculat e emission s an d bes t managemen t practice s t o contro l stormwater runof f woul d als o b o employe d t o contai n contaminan t release s fro m the fin e sla g stockpil e an d durin g implementatio n o f th e contingenc y remedy

. Resourc e utilizatio n mus t als o 

### tak e int o consideratio n an y toxi c leachin g potentia l fo r th e fin e slag

. DECLARATIO N STATEMEN T 

### N o remedia l actio n i s necessar y t o ensur e protectio n o f huma n healt h an d th e environment

.

Ma x H

. Dodson Dat e 

### Assistan t Regiona l Administrato r Ecosystem s Protectio n an d Remediatio n U.S

. Environmenta l Protectio n Agency

, Region VII I

Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 41498P:\32SMI4\FINALROD\OU3ROD2.WP

D

### DECISIO N SUMMAR Y

Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 51298PA3280-014\FINALROD\OU3ROD2.WP

D

### TABL E O F CONTENT S 

### LIS T O F FIGURE S

....................................................... . DS-ii i LIS T O F TABLE S

........................................................ . DS-iv LIS T O F ACRONYM S AN D ABBREVIATION

S

.............................. :



### . DS- v 

### 1 . 0 SIT E NAME

, LOCATION

, AN D DESCRIPTIO

N

........................ .

DS- 1 2 . 0 OPERABL E UNI T HISTOR Y AN D ENFORCEMEN T ACTIVITIE

S

......... . DS- 3 3 . 0 HIGHLIGHT

S O F COMMUNIT

Y PARTICIPATIO

N

..................... .

DS- 5 

### 4. 0 SCOP E AN D ROL E O F OPERABL E UNI T

............................. .

DS- 7 5 . 0 SUMMAR Y

O F SIT E CHARACTERISTIC

S

............................ .

DS- 9 6 . 0 SUMMAR Y

O F SIT E RISK S

........................................ . DS-1 3 6 . 1 RESIDENTIA

L EXPOSUR E T O SLA G

......................... .

DS-1 3 6 . 2 RESIDENTIA

L EXPOSUR E T O IMPACTE D GROUNDWATE R

.... . DS-1 4 6 . 3 RECREATIONA

L USE R EXPOSUR E T O SLA G

................ .

DS-1 4 6. 4 WORKE R EXPOSUR E T O SLA G

.............................. .

DS-1 4 6 . 5 ENVIRONMENTA

L EXPOSUR E T O SLA G

..................... .

DS-1 5 

### 6.5. 1 AQUATI

C EXPOSUR E

................................ .

DS-1 5 6.5. 2 TERRESTRIA

L EXPOSUR E

............................ .

DS-1 5 7. 0 DESCRIPTIO

N O F ALTERNATIVE

S

................................ .

DS-1 6 8 . 0 SUMMAR Y

O F COMPARATIV

E ANALYSI S O F ALTERNATIVE

S

....... . DS-1 8 8 . 1 EVALUATIO

N AN D COMPARISO

N CRITERI A

................. .

DS-1 8 

### 8.1. 1 THRESHOL

D CRITERI A

.............................. .

DS-1 8 8.1. 2 PRIMAR Y

BALANCIN

G CRITERI A

..................... .

DS-1 8 

### 8.1. 3 MODIFYIN

G CRITERI A

............................... .

DS-1 8 

### 8 . 2 EVALUATIN

G TH E STOCKPILE D

FIN E SLA G ALTERNATIVE S

.. . DS-1 9 8.2. 1 OVERAL L PROTECTIO N O F HUMA N HEALT H AN D TH E 

### ENVIRONMEN

T

..................................... . DS-1 9 

### 8.2. 2 COMPLIANC E WIT H APPLICABL E O R RELEVAN T AN D APPROPRIAT

E REQUIREMENT

S (ARARs )

.............. .

DS-1 9 8.2. 3 LONG-TER M EFFECTIVENES

S AN D PERMANENC E

..... . DS-1 9 8.2. 4 REDUCTIO N O F TOXICITY

, MOBILITY

, O R VOLUM E THROUG H TREATMEN

T

.............................. .

DS-2 0 8.2. 5 SHORT-TER M

EFFECTIVENES

S

....................... .

DS-2 0 8.2. 6 IMPLEMENTABILIT

Y

................................ .

DS-2 1 Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 51298P:O2«M)14\F]NALROD\OU3ROD2.WP

D

### 8.2. 7

COS T

............................................... . DS-2 1 

### 8.2. 8 STAT E ACCEPTANC

E

................................ .

DS-2 2 8.2. 9 COMMUNIT

Y ACCEPTANC

E

.......................... .

DS-2 2 8.2.1 0 SUMMAR

Y

.......................................... . DS-2 2 9. 0 SELECTE D REMED Y

............................................. . DS-2 4 10. 0 STATUTOR Y

DETERMINATION

S

.................................. .

DS-2 5 

### 10. 1 PROTECTIO

N O F HUMA N HEALT H AN D TH E ENVIRONMEN

T

.. . DS-2 5 10. 2 COMPLIANC

E WIT H ARAR s

................................ .

DS-2 6 10. 3 COS T EFFECTIVENES

S

..................................... . DS-2 6 10. 4 UTILIZATIO

N O F PERMANEN T SOLUTION S AN D ALTERNATIV E 

### TREATMEN T TECHNOLOGIE S (O R RESOURC E RECOVER Y TECHNOLOGIES

) T O TH E MAXIMU M EXTEN T POSSIBL E

...... . DS-2 6 

### 10. 5 PREFERENC E FO R TREATMEN T A S A PRINCIPA L ELEMEN T

... . DS-2 6 11. 0 DOCUMENTATIO

N O F SIGNIFICAN

T CHANGE S

.................... .

DS-2 7
12. 0 REFERENCE S

................................................... . DS-2 8 APPENDI X A ARARs

.......................................................... . DS-3 0

Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) SI298P:\3280-014\FrNALROD\OU3ROD2.WP

DFIGUR E



### Figur e 1 Figur e 2 Figure s LIS

T O F FIGURE S
General Locatio n Map

, Californi a Gulc h Superfun d Sit e Californi a Gulc h Superfun d Sit e an d Operabl e Units

. Arkansa s Valle y Sla g Pil e Curren t Surfac e Areas

, Volumes

, an d Angle s o f 

### Repos e Figur e 4 Arkansa s Valle y Slag Pil e Sampl e Location s an d Reconnaissanc e Informatio n

Recor d o f Decision Stockpile d Fin e Sla g (OU 3 ) 5129SP:\32«M)M\F1NALROD\OU3ROD2.WP O DS-ii iLIS T O F TABLE S TABL E 

### Tabl e 1 Estimates o f Cost s fo r Remedial Alternative s Tabl e 2 Gri d Compariso n Metho d fo r Alternative s Analysi s

Recor d o f Decisio n Stockpile d Fin e Slag (O U 3 ) JI298P:\3280-014\FINALROD\OU3ROD2.WP

D

### LIS

T O F ACRONYM S AN D ABBREVIATION S AMS L Abov e Mea n Se a Leve l AO C Administrativ e

Orde r o f Consen t ARA R Applicabl e o r Relevan t and Appropriat e Requirement s A V Arkansa

s Valle y BM P Bes t Managemen t Practices CDPH E Colorad o Department o f Publi c Healt h an d Environmen t CERCL A Comprehensiv e

Environmenta l Response

, Compensatio n an d Liabilit y Ac t C F R Cod e o f Federa l Regulation s D&RG W Denve r an d Ri o Grand e Wester n Railroa d EP A U.S

. Environmenta l Protectio n Agenc y F S Fina l Stockpile d Fin e Sla g Feasibilit y Stud y mg/k g milligra m

pe r kilogra m 

### mp h mile s pe r hou r N C P Nationa l

Oi l an d Hazardou s Substance s Pollutio n Contingenc y Pla n N P L Nationa l

Prioritie s Lis t O U Operabl

e Uni t p p m part s pe r millio n 

### PRP s Potentiall y Responsibl e Parties RI/F S Remedia l Investigation/Feasibilit

y Stud y RO D Recor d o f Decisio n S F S Screenin

g Feasibilit y Stud y SPL P Syntheti c Precipitatio n Leachin g Procedur e

Recor d o f Decision Stockpile d Fin e Sla g (O U 3 ) 5I298P:\3280-014\FINALROD\OU3ROD2.WP

D DS- v

### 1 . 0

SIT E NAME

, LOCATION

, AN D DESCRIPTIO N 

### Stockpile d Fin e Sla g Arkansa s Valle y Smelte r Sla g Pil e Californi a Gulc h Superfun d Sit e (Operabl e Uni t 3 ) Leadville

, Colorad o 

### Th e Californi a Gulc h Superfun d Sit e i s locate d i n Lake County

, Colorado

, i n th e uppe r Arkansa s Rive r basin
, approximatel y 10 0 mile s southwest o f Denve r (se e Figur e 1)

. Th e Sit e encompasse s 

### approximatel y 16. 5 squar e miles an d include s th e town s o f Leadvill e an d Stringtown

, a portio n o f th e Leadvill e Histori c Minin g District

, an d th e portio n o f th e Arkansa s Rive r fro m it s confluenc e wit h Californi a Gulc h downstream t o th e Lak e For k Cree k confluence

. Th e Californi a Gulc h Superfun d Sit e ha s bee n organize d int o 1 2 operabl e unit s (OUs)

. Figur e 2 show s th e Sit e boundarie s an d th e locatio n o f O U 3

. Operabl e Uni t 3 (Figur e 2 ) include s thre e sla g pile s (Arkansa s Valley

, L a Plata

, an d Harriso n St. )

owne d b y Denve r and Ri o Grand e Wester n Railroa d (D&RGW)

, a railyar d right-of-wa y throug h 

### Leadvill e and a railyar d i n the are a o f Leadvill e know n a s Povert y Flats

. Thi s Record o f Decisio n (ROD ) addresse s onl y th e fin e slag 1 stockpile d as a subpil e o f th e Arkansa s Valle y (AV ) Smelte r Sla g Pile

. I n addition
, D&RG W ha s identifie d a smal l volum e o f fin e sla g i n th e railyar d (Povert y Flats)

. D&RG W ha s prepare d a pla n whic h addresse s remova l o f th e fin e sla g fro m thi s are a t o th e A V Smelte r Slag Pil e (EPA

, 1996)

. Th e A V Smelte r Sla g Pil e i s th e larges t an d westernmost o f th e thre e sla g pile s owne d b y D&RG W i n th e Leadvill e are a (Figur e 2)

. Thi s pil e was generate d fro m sla g produce d primaril y b y th e A V smelte r facility

, whic h operate d fro m 188 2 t o 1960

. Th e pil e cover s approximatel y 4 0
acre s an d i s approximatel y 9,80 0 fee t abov e mea n se a leve l (AMSL)

. Base d upo n aeria l photography
, th e pil e volume i n th e lat e 1950 s wa s approximatel y 1. 2 millio n cubi c yards

. Today

, approximatel y 422,00 0 cubi c yard s o f sla g remai n o n th e A V Smelte r Sla g Pile

. Th e volum e o f stockpile d fin e sla g a t th e A V Smelte r Sla g Pil e i s approximatel y 190,000 cubi c yards

. Th e sla g pil e wa s purchase d b y D&RG W fro m ASARC O i n 196 1 fo r us e a s ballas t (Terranext

, 1996a)

. Th e A V Smelte r Slag Pil e i s bounde d b y Leadvill e Sewag e Treatmen t Plan t propert y an d Stat e Highwa y 2 4 t o th e south
, ol d smelte r work s t o th e north
, woode d propert y t o th e west , an d othe r smelter-relate d waste s an d Stringtow n t o th e east

. Californi a Gulc h run s adjacen t t o th e sla g pil e vicinit y fo r approximatel y 1/ 5 it s length

. D&RG W ha s performe d wor k nea r th e Californi a Gulc h t o minimiz e th e direc t contac t o f surfac e wate r wit h th e sla g piles

. I n th e vicinit y o f th e A V Smelte r Sla g Pile

, clea n fil l ha s bee n berme d alon g th e to e o f th e sla g t o preven t direc t surfac e wate r fro m contactin g th e sla g (Terranext

, 1996a)

.

'Fin e sla g i s sorte d sla g whic h i s less tha n 3/ 8 inch

. Sorte d sla g i s sla g tha t ha s bee n physicall y separate d int o siz e fraction s fo r th e purpos e o f railroa d ballas t productio n (Terranext

, I996a)

. . Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5I298P:V3280-OI4\FINALROD\OU3ROD2.WP

D

### Lake

Count y i s relativel y smal l (38 0 squar e miles ) an d i s predominatel y rural
, wit h a 199 0 populatio n o f 6,00 7 (U.S

. Departmen t o f Commerce

, 1990)

. Abou t hal f o f thi s populatio n reside s withi n th e Cit y o f Leadville

. Th e populatio n o f Lak e Count y ha s fluctuate d wit h th e 

### minin g industry

. Th e populatio n increase d t o abou t 9,00 0 betwee n 196 0 an d 198 1 an d the n decline d throughou t th e 1980's

. Lan d surroundin g OU 3 i s predominatel y dedicate d t o mining , commercial
, an d residentia l uses

. Th e climat e o f Lake Count y i s dr y bu t otherwis e typica l o f mos t alpin e region s i n th e souther n 

### Rock y Mountains

. Th e averag e annua l maximu m temperatur e i n th e Leadvill e are a i s 50. 5 degree s Fahrenhei t an d th e averag e annua l minimu m temperatur e i s 21. 9 degree s Fahrenheit

, wit h a n annua l mea n temperatur e o f 37. 3 degree s Fahrenheit

. Th e south-centra l portio n o f th e county , a t a n elevatio n nea r 9,00 0 fee t AMSL

, receive s abou t 1 0 inche s o f precipitatio n annually

. 

### Win d i s predominantl y fro m the northwest
, wit h speed s typicall y fro m 0 t o 3 0 mile s pe r hou r (mph ) (WCC

, 1993)

. Populate d area s o f Leadvill e ar e predominantl y upwin d o f th e A V Smelte r Sla g Pile

.

Recor d o f Decisio n Stockpile d Fin e Slag (O U 3 ) P. O
~ 3I298P:\3280-OI4\FINALROD\OU3ROD2.WP

D U&-2.

### 2 . 0

OPERABL E UNI T HISTOR Y AN D ENFORCEMEN T ACTIVITIE S Th e Californi a Gulc h Superfun d Sit e i s locate d i n th e highl y mineralize d Colorad o Minera l Bel t
o f the Rock y Mountains

. Mining

, minera l processing , and smeltin g activitie s hav e produce d gold
, silver
, lead
, an d zin c fo r mor e tha n 13 0 year s i n th e Leadvill e area
. Minin g an d it s relate d industries continu e t o b e a sourc e o f incom e fo r bot h Leadvill e and Lake County

. The Leadvill e Histori c Minin g District include s a n extensiv e networ k o f undergroun d min e working s i n a 

### mineralized are a o f approximatel y 8 squar e mile s locate d aroun d Breec e Hill

. Minin g i n th e Distric t bega n i n 1860 , whe n place r gol d wa s discovere d i n Californi a Gulch

. A s th e place r 

### deposit s wer e exhausted
, undergroun d working s becam e th e principl e metho d fo r removin g gold
, silver
, lead
, an d zin c ore
. A s thes e mine s wer e developed
, wast e roc k wa s excavate d alon g wit h 

### th e or e an d place d nea r th e min e entrances

. Or e wa s crushe d an d separate d int o metalli c 

### concentrate s at mills
, wit h mil l tailin g generall y slurried int o tailin g impoundments

. Approximatel y 1 7 smelte r facilitie s ar e reporte d t o hav e onc e operate d withi n the Site

. Mos t operation s cease d b y abou t 1900 , althoug h som e facilitie s continue d t o operat e int o th e 1960's

. A t present , nearl y al l o f the mine s withi n the Sit e boundarie s ar e inactive ; onl y a fe w small-to

- moderate-size d minin g operation s exist

. Al l o f th e mill s and smelter s whic h operate d onsit e are inactiv e and/o r demolished

. 

### Du e t o histori c mining , milling
, an d smeltin g operations , th e Sit e contain s man y tailing s impoundments
, fluvia l deposits
, sla g piles
, wast e roc k piles
, an d min e wate r drainag e tunnels

. Sla g o n the Sit e i s the mineralize d wast e byproduc t o f smelting
, and result s fro m the processin g o f lea d ore i n hig h temperatur e furnaces

. Thre e majo r sla g pile s an d severa l smalle r pile s remai n a t th e Sit e (Figur e 2)

. I n 1961 , D&RG W purchase d th e A V Smelte r Sla g Pil e fro m ASARC O fo r us e as railroa d ballast

. D&RG W purchase d th e L a Plat a sla g pil e fro m th e Leadvill e Sanitatio n Distric t in 1970

. Additionally

, D&RG W purchase d th e Harriso n Stree t Sla g Pil e fro m N L Industrie s i n 198 3 (EPA

, 1996)

. 

### Th e Californi a Gulc h Sit e wa s place d o n th e Nationa l Prioritie s Lis t (NPL ) i n 1983 , under th e authorit y o f th e Comprehensiv e Environmenta l Response

, Compensation

, an d Liabilit y Ac t (CERCLA ) o f 1980

. The Sit e wa s place d o n the NP L because o f concern s abou t the impac t o f 

### min e drainag e o n surfac e water s i n th e Californi a Gulc h an d th e impac t o f heav y metal s loadin g int o th e Arkansa s Rive r (EPA

, 1996)

. Several subsequen t investigations wer e conducte d withi n th e Californi a Gulc h Superfun d Sit e tha t hav e addresse d th e sla g a t th e three D&RGW-owne d 

### piles

. I n 1986 , th e EPA' s contractor , CH2 M Hill

, sample d surfac e water , groundwater
, an d numerou s min e wast e piles
, an d thre e D&RG W sla g pile s a s par t o f th e Californi a Gulc h Sit e Remedia l Investigatio n (RI ) (EPA

, 1989)

. Th e objectiv e o f th e min e wast e an d sla g samplin g wa s t o bette r characteriz e th e material s i n th e Californi a Gulc h Superfun d Site

. Thi s was th e firs t tim e tha t th e 

### EP A had sample d sla g a t th e Site

. I n 1988 , Jame s P

. Wals h an d Associates

, Inc

. conducte d a Soil s Investigation

. Th e state d objective s o f thi s stud y wer e t o defin e potentia l actio n level s fo r soil
, determin e backgroun d Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5I298P:\3280-OI4\FINALROD\OU3ROD2.WP

D

### metal

s conten t o f soils
, delineat e the exten t o f soi l contamination , and determin e source s o f soi l contamination

. Thi s stud y was initiate d b y ASARCO

, another potentiall y responsibl e part y 

### (PRP ) a t th e Site

. Thre e sample s o f sla g wer e collecte d a s par t o f thi s study : one fro m th e Harriso n Stree t pile
, on e fro m th e L a Plat a pile
, an d on e fro m a n are a wes t o f Leadville

. Thi s stud y did no t includ e th e A V Smelte r Sla g Pil e (MK

, 1992)

. I n Ma y 1989 , Jacobs Engineerin g performe d a secon d samplin g o f sla g fo r th e EPA

. Th e 

### purpos e o f th e stud y wa s t o determin e th e concentration s o f metal s i n th e thre e D&RG W sla g pile s and t o evaluat e the potentia l fo r migratio n o f thes e metal s t o soil
, wate r o r air

. Potentia l hazard s t o the environmen t and publi c healt h fro m the sla g i n Leadvill e wer e evaluated

. 

### O n Decembe r 3,1991 , EP A an d D&RG W entere d int o a n Administrativ e Orde r o n Consen t (AOC)

, CERCL A
- VII I
- 92006 , fo r th e performanc e o f a remedia l investigation/feasibilit

y stud y (RI/FS ) o f th e lea d sla g piles

. Prio r t o th e AOC

, EP A ha d studie d th e sla g pile s a s par t o f othe r investigation s at the Site

. I n 1992 , D&RG W performe d a n R I (MK

, 1992 ) tha t addresse d
seve n lea d sla g piles
, includin g th e Arkansa s Valley

, Harrison

, an d L a Plat a sla g piles
, an d on e 

### zin c sla g pile

. Followin g th e RI

, a Site-Wid e Screenin g Feasibilit y Stud y (SFS ) wa s undertake n a s a join t effor t between th e PRP s an d EPA

. Th e SF S wa s complete d i n Marc h 1993

. I t 

### screene d severa l remediatio n alternative s fo r al l type s o f sla g locate d a t th e A V Smelte r Sla g Pil e base d o n specifi c criteria , suc h a s relativ e cost , implementability
, an d effectiveness

. The three alternative s retaine d fo r furthe r evaluatio n were : no action , institutiona l controls
, an d resourc e utilizatio n (EPA

, 1996)

. O n Decembe r 15,1993 , D&RG W entered int o a Consent Decre e wit h EP A t o perfor m th e remainde r o f thei r sit e work

. Th e Consent Decre e state d EPA' s concern s regardin g th e fin e fractio n o f th e stockpile d sla g an d th e potentia l fo r particulat e releas e durin g ballas t operation s as a potentia l huma n healt h exposur e pathway

. Th e Consen t Decre e require d D&RG W t o perfor m a feasibilit y stud y fo r stockpile d fin e sla g an d t o submi t a n operation s pla n befor e initiatin g an y ballas t operations

. I n Jul y o f 1995 , D&RG W submitte d a ballas t operation s pla n t o EPA

. Followin g EPA' s approva l o f th e plan
, ballas t operation s commenced i n Augus t 199 5 (EPA

, 1996)

. I n Ma y o f 1996 , D&RG W submitte d a feasibilit y stud y fo r th e stockpile d fin e sla g (th e FS ) a t th e A V Smelte r Sla g Pile

, accordin g t o th e term s o f th e Consent Decree

. Th e existin g fin e sla g subpil e an d fin e sla g potentiall y generate d fro m futur e ballas t productio n wer e th e focu s o f th e F S

. Th e F S provide d a detaile d analysi s o f th e thre e retaine d remediatio n alternative s fro m th e S F S a s applie d t o th e stockpile d fin e slag

. Th e resul t o f th e Feasibilit y Stud y fo r th e stockpile d fin e sla g was a Propose d N o Actio n Pla n fo r th e stockpile d fin e sla g as a subpil e o f th e A V 

### Smelte r Sla g Pil e (EPA

, 1996)

.

Recor d o f Decision Slockpile d Fin e Sla g (O U 3 ) SI298P:\3280-OI4\FINALROD\OU3ROD2.WP

D

### 3 . 0

HIGHLIGHT

S O F COMMUNIT Y PARTICIPATIO

N Publi c participatio n i s require d b y CERCL A Section s 11 3 an d 117

. Thes e section s requir e tha t befor e adoptio n o f an y pla n for remedial actio n t o b e undertake n b y EPA

, th e State

, or a n 

### individua l (PRP)

, th e lead agenc y shall : 1

. Publis h a notic e an d brie f analysi s o f th e Propose d Pla n an d mak e suc h pla n availabl e t o th e public ; an d


### 2

. Provid e a reasonabl e opportunit y fo r submissio n o f writte n an d ora l comment s an d a n opportunit y fo r a publi c meetin g a t o r nea r th e Sit e regardin g th e Propose d 

### Pla n an d an y propose d finding s relatin g th e cleanu p standards

. Th e lea d agenc y shal l kee p a transcrip t o f th e meetin g an d mak e suc h transcrip t availabl e t o th e public

. The notic e and analysi s publishe d under ite m # 1 abov e shal l includ e sufficien t informatio n t o provid e a reasonabl e explanatio n o f th e Propose d Pla n an d alternativ e proposal s considered

. Additionally

, notice o f th e fina l remedia l actio n pla n se t fort h i n th e RO D mus t b e published
, an d th e pla n mus t b e mad e availabl e t o th e publi c befor e commencin g an y remedia l action

. Suc h a fina l pla n mus t b e accompanie d b y a discussio n o f an y significan t change s t o th e preferre d remed y presente d i n the Propose d Pla n alon g wit h the reason s fo r the changes

. A respons e (Responsivenes s Summary ) t o eac h o f th e significan t comments , criticisms , an d new dat a submitte d i n writte n o r ora l presentation s durin g th e publi c commen t perio d mus t b e include d wit h th e ROD

. EP A ha s conducte d th e require d communit y participatio n activitie s throug h presentatio n o f th e RI/F S an d Propose d Plan

, a 30-da y publi c commen t period
, a forma l publi c hearing
, an d presentatio n o f th e Selecte d Remed y i n thi s ROD

. However

, sinc e th e EP A di d no t receiv e an y writte n publi c comment s o n th e Propose d N o Actio n Pla n fo r th e Stockpile d Fin e Slag

, thi s RO D doe s no t contai n a Responsiveness Summary

. 

### T h e Propose d N o Actio n Pla n fo r Stockpile d Fin e Slag a t th e A V Smelte r Sla g Pil e wa s release d fo r publi c commen t o n Septembe r 27,1996

. Th e RI/F S an d th e Propose d N o Actio n Pla n wer e mad e availabl e t o th e publi c i n th e Administrativ e Recor d locate d a t th e EP A Superfun d Record s Cente r i n Denve r and the Lak e Count y Publi c Librar y i n Leadville

. A forma l publi c commen t perio d wa s designate d fro m Septembe r 27 , throug h Octobe r 28,1996

. 

### O n Octobe r 3,1996 , th e EP A hoste d a publi c meetin g t o presen t th e Propose d Pla n for Stockpile d Fin e Slag at O U 3 o f the Californi a Gulch Superfun d Site

. The meetin g wa s hel d at 

### 7:0 0 p m i n th e Minin g Hal l o f Fam e i n Leadville

, Colorado

. Representative s fro m th e EP A an d D&RG W presente d th e Propose d Plan

. Thre e alternative s wer e discussed : N o Action

, Institutiona l Controls

, an d Resourc e Utilization

. Th e N o Actio n alternativ e wa s presente d a s EPA' s an d D&RGW' s preferre d alternative

. A portio n o f th e hearin g wa s dedicate d t o acceptin g forma l ora l comment s fro m th e public

. Onl y tw o question s wer e raise d durin g thi s publi c
Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 51298P:\3280-OM\FINALROD\OU3ROD2.WP

D

### meeting

.

Thes e question s wer e i n regar d t o th e volum e o f th e fin e sla g propose d fo r N o Actio n an d th e natur e o f th e soi l beneat h th e Harriso n St

. sla g pile
, whic h i s no t relevan t t o thi s ROD

.

Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5I298P:\3280-OM\FINA1.ROD\OU3ROD2.WP

D

### 4. 0

SCOP E AN D ROL E O F OPERABL E UNI T The Californi a Gulc h NP L Sit e cover s a wid e are a (Figur e 2)

. EP A ha s establishe d the followin g OU s fo r th e cleanu p o f geographically-base d

area s withi n th e Site

. Th e OU s ar e designate d as : OU 1 Ya k Tunnel/Wate r Treatmen t Plant 

### O U 2 Malt a Gulc h Fluvia l Tailing/Leadvill e Corporatio n Mill/Malt a Gulc h Tailing s Impoundment s 

### O U S D&RG W Sla g Piles/Railroa d Easement/Railroa d

Yar d an d Stockpile d Fin e Slag OU 4 Uppe r Californi a Gulc h O U S ASARC O Smelter/Slag/Mil l Site s O U 6 Star r Ditch/Penros e Dump/Stra y Hors e Gulch/Evan s Gulc h OU 7 Apach e Tailin g Impoundment s 

### OU S Lower Californi a Gulc h OU 9 Residentia l Populate d Area s OU1 0 Orego n Gulc h 

### OU1 1 Arkansa s Rive r Valle y Floodplai n OU1 2 Sit e Wate r Qualit y 

### T h e purpos e o f th e D&RG W Slag Piles/Railroa d Easement/Railroa d

Yar d O U RI/F S was t o gathe r sufficien t informatio n t o suppor t a n informe d ris k managemen t decisio n o n whic h remedie s ar e th e mos t appropriat e fo r th e D&RG W Stockpile d Fin e Slag portio n o f OUS

. Th e RI/F S wa s performe d i n accordance wit h the Nationa l Oi l and Hazardou s Substance s Pollutio n Contingenc y Pla n (NCP)

, 4 0 Cod e o f Federa l Regulations (CFR ) Par t 300 , and CERCL A 

### Sectio n 104,4 2 U.S.C

. § 9604

. Th e objective s o f th e RI/F S wer e to :
• Determin e th e natur e an d exten t o f metal s i n sourc e area s an d othe r affecte d area s withi n th e D&RG W Sla g Piles/Railroa d Easement/Railroa d

Yar d OU ;
• Defin e th e potentia l pathways alon g whic h metal s ca n migrate , a s wel l a s th e physica l 

### processes and
, t o the exten t necessary , the chemical processe s tha t control thes e pathways ;
• Determin e ris k assessmen t informatio n includin g potentia l receptors , exposur e patterns , 

### and foo d chai n relationships ; and

• Develop

, screen , and evaluat e remedia l alternative s and predic t th e consequence s o f eac h 

### remedy

. Base d o n the finding s o f previou s investigations and the result s o f the D&RG W Sla g Piles/Railroa d Easement/Railroa d

Yar d O U RI/FS

, th e source s an d area s o f environmenta l contaminatio n a t th e Stockpile d Fin e Slag (A V Smelte r Slag Pile ) portio n o f OU S hav e bee n adequatel y delineated

. Recor d o f Decisio n Stockpile d Fin e Slag (O U 3 } 3I29SPA3280-OI4\FINALROD\OU3ROD2.WP

D

### Th e

remed y outline d i n thi s RO D represent s th e fina l remedia l actio n onl y fo r th e stockpile d fin e sla g a t th e A V Smelte r Sla g Pile

. Remedia l action s undertake n a t th e Stockpile d Fin e Sla g portio n o f OU 3 ar e intende d t o b e consistent wit h th e remedia l actio n objective s an d goal s identifie d fo r th e Californi a Gulc h NP L Sit e an d othe r O U investigations

.

Recor d o f Decisio n Stockpile d Fin e Sla g 51298P;\3280-OI4\FINALROD\OU3ROD2.WP

D Stockpile d Fin e Sla g (OU 3 ) DS- 8

### 5 . 0

SUMMAR Y O F SIT E CHARACTERISTIC

S A s a resul t o f D&RG W processin g th e sla g fo r us e a s railroa d trac k ballast
, th e A V Smelte r Sla g Pil e i s actuall y compose d o f severa l sub-pile s (Figur e 3)

. Th e subpile s o f th e A V Smelte r Slag Pil e sit e includ e sorted fines

, water-quenche d fines

, ballast-size d material
, oversize d material
, 

### an d unsorted air-cooled slag

. The subpile s o f sorte d fine s consist o f th e les s tha n 3/ 8 inc h diamete r slag

. Th e ballast-size d subpil e i s compose d o f materia l wit h particl e size s rangin g fro m 

### approximatel y 3/ 8 inc h t o 2-1/ 2 inche s i n diameter

. Two subpile s o f oversized material fro m ballas t processin g consis t o f sla g tha t i s greater tha n 2-1/ 2 inche s i n diameter
, som e brick
, an d
som e scra p iron

. Th e existin g fine s pile s an d fine s potentiall y generate d fro m futur e ballas t 

### productio n are th e focu s o f thi s ROD

. Figur e 3 als o depict s th e locatio n o f stockpile d fin e sla g a t th e A V Smelte r Sla g Pile

. Thi s an d a smal l amoun t o f fin e sla g i n th e railyar d ar e th e onl y location s withi n th e Californi a Gulc h Superfun d Sit e wit h stockpile d fin e slag

. Th e volum e o f 

### stockpile d fin e sla g a t th e A V Smelte r Sla g Pil e i s approximatel y 190,00 0 cubi c yards

. Th e volum e o f stockpile d fin e sla g a t th e railyar d wa s estimate d a t approximatel y 22 0 cubi c yard s 

### (Terranext

, 1996b)

. A s note d previously
, the smal l amoun t o f fin e sla g at the railyar d ha s bee n move d t o th e A V Smelte r Sla g Pile

. Th e total volum e o f fin e sla g move d fro m th e railyar d t o th e A V Smelte r Sla g Pil e wa s approximatel y 120 0 cubi c yards

. 

### The followin g paragraphs discus s th e primar y contaminant s o f concern , summariz e th e natur e and exten t o f contamination , and provid e a brie f descriptio n o f contaminan t fat e and transport

. Sit e Characterizatio n

Summar y - Stockpile d Fin e Sla g Durin g th e Lea d Sla g Pil e R I (MK

, 1992 ) a tota l o f 1 8 sla g sample s wer e collecte d fro m th e A V 

### Smelte r Sla g Pil e (Figur e 4)

. Fou r o f thes e sample s wer e collecte d fro m th e sorte d fine s an d fou r fro m th e water-quenche d fine s subpiles

. Thes e sample s wer e collecte d fro m th e surfac e t o a dept h o f 3 feet

. I n addition
, fou r subsla g sample s wer e collecte d fro m fou r coreholes drille d a t th e A V Smelte r Sla g Pile

. Tw o o f thes e subsla g sample s wer e collecte d fro m directl y belo w th e water-quenched fine s subpile

. Eac h sampl e wa s submitte d fo r laborator y compositiona l an d teachabilit y analysis

. Materia l fro m th e finer-graine d sla g pile s wa s als o submitte d fo r particl e 

### siz e testing

. Compositiona l analyse s include d tota l metals
, water-solubl e anions , an d acid-bas e accounting

. Leachabilit y testin g include d Syntheti c Precipitatio n Leachin g Procedur e (SPLP ) (EP A Metho d 1312 ) and colum n leac h tests , whic h wer e intende d t o simulate
, a s closel y a s 

### possible
, i n sit u condition s (Terranext

, 1996a)

. Compositiona l result s showe d tha t th e sla g i s a n iro n magnesiu m silicate
, wit h residua l bas e metals

. Concentratio n mean s fo r th e fou r primar y metal s o f concer n collecte d fro m fin e sla g sampl e location s a t th e Sit e are a s follows :
• Arseni c means ; 43 5 milligra m pe r kilogra m (mg/kg ) -sorte d fines

, 90 9 mg/k g 

### wate r quenche d fine s • Cadmiu m means ; 11. 9 mg/kg-sorte d fines

, 16. 6 mg/k g water-quenched fine s
Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5I29SP:\32SO-OU\FINALROD\OU3ROD2.WP

D

### •

Lea d means ; 10,80 0 mg/kg-sorte d fines

, 9,65 0 mg/k g water-quenche d fine s • Zinc means ; 44,00 0 mg/kg-sorte d fines

, 73,00 0 mg/k g water-quenche d fine s 

### Compositiona l result s fo r th e tw o subsla g soi l sample s (AVB10 3 an d ABV104 ) collecte d beneat h th e water-quenche d fine s showe d concentration s o f metal s o f concer n t o b e significantl y 

### lowe r tha n thos e fo r th e sla g material
, an d withi n th e rang e o f literatur e value s fo r metal s occurrin g naturall y i n soi l (MK

, 1992-Tabl e 4-15)

. Thes e sample s showe d the lowes t valu e fo r arseni c (5. 7 mg/kg)

, lea d (84. 8 mg/kg ) an d fo r zin c (18 8 mg/kg ) fro m al l subsla g soi l samples collected

. Site-specifi c backgroun d ha s no t bee n established
, however
, range s fo r metal s o f

concer n i n Colorad o soil s ar e a s follows : arseni c (1.2-2 4 mg/kg)

, lea d 15-15 0 mg/kg ) an d zin c (16-30 0 mg/kg ) (Terranext

, 1996a)

. Th e subsla g soi l sample s collecte d fro m beneat h th e water

quenche d fin e sla g a t A V exhibite d a negativ e acid-formin g potential

. Leachin g analysis
, whic h include d bot h SPL P and colum n leac h studies
, showe d minima l 

### leachin g o f metal s o f concern
. Syntheti c Precipitatio n Leachin g Procedur e result s fo r al l element s teste d i n sla g wer e belo w the toxicit y characteristi c criteria , liste d i n 4 0 CF R 261.24

. 

### Mea n value s for th e contaminant s o f concer n wer e generall y tw o order s o f magnitud e lowe r tha n thes e regulator y thresholds

. Colum n leac h test s showe d simila r lo w level s o f leachin g (Terranext

, 1996a)

. Particl e siz e dat a an d site-specifi c meteorologica l dat a wer e use d t o determin e whethe r sla g i n th e fine-graine d pile s ha s th e abilit y t o becom e airborne

. Threshol d frictio n velocitie s (th e win d spee d abov e whic h th e surfac e materia l become s airborne ) wer e calculate d usin g th e mod e o f th e aggregat e siz e distribution

. Win d dat a an d th e heigh t o f th e pile s wer e use d t o calculat e th e frictio n velocity

. Result s fo r th e tw o fine s pile s are : Threshol d Frictio n Velocit y sorte d fine s 1. 0

meter s pe r secon d (m/sec ) water-quenche d fine s 0.5 8 m/se c Frictio n Velocit y 0.5

5 m/se c A frictio n velocit y lowe r than th e threshol d frictio n velocit y demonstrate s tha t sustaine d win d gust s (0.5 5 m/sec

, M K 1992 ) i n Leadvill e ar e no t fas t enoug h t o caus e win d erosio n o f th e fine s sla g piles

. Groundwate r 

### A site-wid e monitorin g progra m wil l b e develope d a t th e Californi a Gulc h Superfun d Sit e onc e al l sourc e area s hav e bee n addressed

. Groundwate r i n th e vicinit y o f th e stockpile d fin e sla g ha s no t bee n full y characterized

. A s noted above
, th e subsla g materia l showe d concentrations o f metal s o f concer n t o b e significantl y lowe r tha n thos e fo r th e sla g material
, an d within th e rang e o f literatur e value s fo r metal s occurrin g naturall y i n soils

. Thes e result s sugges t tha t surfac e wate r infiltratio n throug h th e sla g pile s doe s no t significantl y impac t groundwate r no r doe s i t impac t th e soil s beneat h th e sla g piles
, a s evidence d b y th e result s o f th e soi l analyses (Terranext

, 

### 1996a)

. Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5I298P:\328(W)I4\FINALROD\OU3ROD2.WP

DSurfac e

Wate r 

### N o discree t conveyance s o f surfac e wate r runof f fro m th e A V are a hav e bee n noted

. Additionally

, the ber m place d alon g the Californi a Gulc h i s designe d t o eliminat e surfac e wate r runof f fro m directl y enterin g th e Californi a Gulc h (Terranext

, 1996a)

. Soil s

« • 

### Analysi s o f subsla g soil s fro m beneat h th e fin e sla g pile s sho w th e lowes t concentratio n fo r lead
, 

### arseni c an d zin c o f an y o f th e subsla g sample s collecte d (Terranext

, 1996a)

. Discussio n o f Fat e an d Transpor t 

### Existin g pathway s fo r potentia l migratio n o f metal s o f concer n includ e wind
, leaching
, mixin g b y huma n activities , runoff

, an d direc t contact

. Releas e Mechanis m 1 - Win d Th e ai r pathwa y analysi s result s indicat e tha t win d erosio n i s no t a viabl e releas e mechanism for th e lea d sla g piles
, includin g th e A V water-quenche d an d sorte d fine s piles

. Releas e Mechanis m 2 - Leachin g Testin g i n subsla g materia l doe s no t indicat e tha t leachat e fro m sla g contribute s t o elevate d metal s concentration s i n the vados e zon e beneat h the sla g piles

. Thi s conclusio n i s supporte d b y the lac k o f acid-generatin g potentia l an d the neutral-to-basi c p H o f the sla g an d subsla g materials

. Releas e Mechanis m 3 - Mixin g b y Huma n Activitie s 

### Transpor t o f sla g b y huma n activitie s ha s occurred
, a s i t wa s historicall y use d fo r roa d maintenanc e withi n th e Sit e b y Lak e Count y an d th e Colorad o Departmen t o f Transportation

. Thi s mechanis m wil l no t continu e i n th e futur e a s reus e o f th e sla g materia l i s controlle d a s specifie d i n thi s ROD

. Releas e Mechanis m 4 - Surfac e Wate r Runof f 

### N o evidenc e o f transpor t o f sla g fine s b y surfac e wate r runof f wa s observe d a t an y o f the examine d piles

. Sla g doe s no t appea r t o b e transporte d fro m pile s ont o adjacen t soil s i n rivulet s o r channels

. Pil e integrity , especiall y fo r fine s pile s wher e thi s i s mos t critical
, appear s intact

. This potentia l releas e mechanis m fo r sla g i s no t a concer n at th e A V Smelte r Sla g Pile

.

Recor d o f Decisio n Stockpile d Fin e Slag (O U 3 ) S1298P:\3280-OI4\FINALROD\OU3ROD2.WP

DReleas e

Mechanis m 5 - Direc t Contac t 

### Due t o th e physica l characteristic s o f th e sla g piles
, direct contac t wit h th e sla g pile s wa s 

### considered unlikel y i n EPA' s Preliminar y Baselin e Huma n Healt h Ris k Assessmen t (EP A 1991)

. Therefore

, i t wa s eliminate d a s a releas e mechanism

.

Recor d o f Decision Stockpile d Fin e Sla g (O U 3 )

n c , 51298P:V3280-014\FINALROD\OU3ROD2

.

WP D L»O- 1

### 6. 0 SUMMAR Y O F SIT E RISK S I n th e Preliminar y Baseline Huma n Healt h Ris k Assessment (EPA

, 1991 ) lea d and arseni c wer e identifie d a s th e primar y chemical s o f potentia l concer n a t th e Californi a Gulc h NP L Site

. Sinc e th e completio n o f th e preliminar y ris k assessment , severa l importan t studie s wer e complete d tha t provide d mor e extensiv e an d mor e reliabl e dat a o n environmenta l concentration s an d o n huma n an d ecologica l exposures

. Leadvill e official s an d busines s leader s expresse d concer n ove r possibl e risk s an d liabilitie s associated wit h commercia l an d recreationa l use s withi n th e Site

. Therefore

, i n th e fina l baselin e ris k assessment , risk s pose d b y environmental contaminatio n t o curren t o r futur e worker s i n th e commercia l an d busines s distric t o f th e communit y an d t o peopl e wh o engag e i n recreationa l activitie s i n an d aroun d th e communit y wer e evaluated

. Th e assessmen t wa s conducte d t o determin e i f environmenta l contaminatio n wa s o f concer n a t an y location s presentl y zone d commercial/industria l

an d t o addres s concern s regardin g th e developmen t o f a propose d bik e pat h aroun d th e communit y (EPA

, 1996)

. I n 1995 , EP A complete d tw o part s o f th e Baselin e Huma n Healt h Ris k Assessment s fo r th e Californi a Gulc h Superfun d Site

. Thes e are : Par t A Risk s t o Resident s fro m Lea d (EPA

, 1995b)

, an d Par t C Evaluatio n o f Recreational

, Worke r Scenario s (EPA

, 1995c)

. Par t A evaluate s risk s t o resident s fro m lead ; an d Par t C evaluate s risk s t o worker s i n th e commercia l

an d busines s distric t an d t o recreationa l user s i n area s i n an d aroun d th e community

. Th e 

### followin g paragraph s summariz e result s o f th e fina l baselin e ris k assessmen t a s the y relat e t o th e stockpile d fin e sla g a t th e A V Smelte r Slag Pile

. Terrestria l an d aquati c risk s associate d wit h exposur e t o sit e chemical s wer e als o evaluate d b y EPA

. Aquati c risk s wer e evaluate d i n th e Fina l Baselin e Aquati c Ecologica l Ris k Assessmen t (EPA

, 1995d ) an d terrestria l risk s wer e evaluate d i n th e Ecologica l Ris k Assessmen t fo r th e Terrestria l Ecosyste m (EPA

, 1997)

. 6 . 1 RESIDENTIA

L EXPOSUR E T O SLA G 

### Th e evaluatio n o f exposur e t o contaminant s a t wast e pile s include d consideratio n o f sla g pil e data
, wit h an exposur e scenari o conservativel y evaluatin g a chil d playin g o n the wast e pile s wh o ma y com e i n contac t wit h contaminant s throug h inadverten t ingestio n o r dermal (skin ) contact

. Th e derma l contac t pathwa y wa s determine d t o b e minima l an d wa s no t considere d further

. Th e 

### residentia l ris k assessmen t als o determine d tha t non-lea d metal s i n mos t wast e pile s pos e eithe r no ris k o r onl y lo w ris k fro m direc t contact whil e playin g o n the piles

. Fo r the evaluatio n o f lea d 

### exposur e a t th e wast e piles
, th e dat a wer e foun d t o b e to o limite d t o derive reliabl e estimates o f th e potentia l impac t o f direc t exposure s t o childre n who pla y o n wast e piles

. Therefor e a quantitativ e evaluatio n wa s no t performed

. A s state d i n th e preliminar y ris k assessmen t an d th e SFS

, direct contac t o f resident s wit h th e sla g pile s i s no t expecte d t o occur
. Win d erosion and direc t contact wer e not considere d viabl e releas e mechanism s fo r the stockpile d fin e slag

. However

, base d on th e result s o f th e ris k assessment , there i s som e concer n 

### abou t th e potentia l for paniculat e releas e an d huma n exposur e shoul d resourc e utilizatio n o f th e stockpile d fin e sla g b e undertaken

. Fo r example
, inhalatio n o f sla g particle s coul d occu r i f th e Recor d o f Decisio n Stockpile d Fin e Sla g (OU 3 ) 5I29«P:\3280-OI4\FINALROD\OU3ROD2.WP

D

### materia

l i s disturbe d fro m it s curren t state

. I f th e resourc e utilizatio n optio n i s exercised
, measure s woul d b e require d t o prevent contaminan t releases

. 6 . 2 RESIDENTIA

L EXPOSUR E T O IMPACTE D GROUNDWATE R Th e remedia l actio n objectiv e i n th e 199 3 SF S wa s t o preven t leachin g o f metal s o f concer n i n 

### concentration s tha t woul d hav e a n adverse impac t o n soils
, surfac e water , o r groundwate r i n th e are a nea r th e sla g piles

. Th e 199 6 F S determine d tha t testin g o f materia l unde r th e sla g pil e di d

no t indicat e tha t migratio n o f contaminant s b y leachin g fro m th e sla g contributes t o elevate d metal s beneat h th e sla g piles

. I n addition
, th e fina l baseline ris k assessmen t determine d tha t 

### groundwate r fro m thi s aquife r i s not currentl y use d fo r drinking
, and i t i s relativel y unlikel y tha t i t wil l b e use d fo r drinkin g i n th e future

. I t ha s bee n determine d tha t ther e i s a minima l potentia l 

### fo r releas e o f metal s i n leachat e fro m th e stockpile d fin e slag
, an d tha t th e stockpile d fin e sla g poses an insignifican t impac t o n wate r qualit y (EPA

, 1996)

. 6 3 RECREATIONA

L USER EXPOSUR E T O SLA G Th e A V Smelte r Sla g Pil e are a i s situate d i n a n are a presentl y zone d a s industrial/minin g an d i s no t considere d a recreational us e area , thus
, ther e i s n o complet e exposur e pathway

. 6 . 4 WORKE R EXPOSUR E T O SLA G Ther e ar e n o curren t worke r exposur e pathway s t o th e stockpile d fin e slag

. Th e Selecte d Remed y provide s a contingenc y fo r resourc e utilization
, whic h ma y b e undertake n i n the future

. T h e EP A ha s determine d tha t resourc e utilizatio n o f th e stockpile d fin e sla g i s onl y appropriat e i f i t i s encapsulate d fo r reuse , t o dete r th e potentia l releas e o f airborn e particulate s an d eliminat e potentia l ris k associate d wit h resourc e utilizatio n activities

. Encapsulatio n ca n includ e th e us e o f fin e sla g i n concret e o r asphal t aggregate ; o r a s roa d base
, backfil l o r othe r constructio n material

a s lon g a s the fin e sla g i s chemicall y boun d o r physicall y separate d fro m an y exposur e scenari o b y a barrie r consistin g o f anothe r material

. Dus t suppressant s t o contro l particulat e emission s and bes t managemen t practice s t o contro l stormwate r runof f woul d als o b e employe d t o contai n contaminan t release s durin g implementatio n o f th e contingenc y remedy

. 

### I n respons e t o concern s raise d b y Leadvill e official s an d busines s leader s ove r potentia l liabilit y associate d wit h busines s developmen t withi n a Superfun d Site

, EP A develope d actio n level s t o determin e i f chemica l concentration s wer e o f concer n a t an y location s presentl y zone d fo r commercia l an d industria l purposes

. Actio n level s wer e develope d onl y fo r arseni c an d lead
, th e contaminant s o f mos t concer n at th e Site

. Th e actio n level s wer e develope d onl y fo r soi l an d dus t ingestion ; exposur e t o othe r medi a (e.g.

, sla g piles
, wast e piles ) an d exposur e t o soil/dus t vi a othe r pathway s (e.g.

, dermal ) ar e considere d o f insignifican t concer n fo r workers

. The soi l actio n leve l fo r lea d base d o n commercial/industria l

exposur e t o soi l and dus t range d fro m a s low a s 2,20 0 part s per millio n (ppm ) t o a s hig h a s 19,10 0 pp m wit h centra l tendenc y value s i n th e 6,10 0 t o 7,70 0 pp m range
. Lea d concentrations i n soil s i n an d aroun d th e sla g pile s (maximu m lea d concentratio n o f 79 4 ppm ) wer e wel l belo w th e lea d actio n leve l (EP A 1996)

. Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5l29SP:\32«WH4\nNALROD\OU3ROD2.WP

D

### Soi

l actio n level s fo r arseni c base d o n commercial/industria l

exposur e t o soi l an d dus t range d fro m a s lo w a s 33 0 pp m t o a s hig h a s 1,30 0 ppm , wit h centra l tendenc y value s i n th e 61 0 t o 69 0 pp m range
. Arseni c concentration s i n soil s i n an d aroun d th e sla g pile s (maximu m arseni c 

### concentratio n o f 5. 7 ppm ) wer e wel l belo w th e lowest arseni c action level

. 6 . 5 ENVIRONMENTA

L EXPOSUR E T O SLA G
6.5. 1 AQUATI C EXPOSUR E 

### Ther e ar e n o aquati c exposur e pathways t o stockpile d fin e sla g due t o the lac k o f releas e mechanisms

. N o evidenc e o f transpor t o f sla g fine s b y surfac e wate r runof f wa s observe d a t an y o f th e examine d piles

. Sla g doe s no t appea r t o b e transporte d fro m pile s ont o adjacen t soil s i n rivulet s o r channels

. Pil e integrity , especiall y fo r fine s pile s wher e thi s i s mos t critical
, appear s 

### intact

. Surfac e wate r runof f i s no t a potentia l releas e mechanis m fo r th e A V Smelte r Sla g Pile

. Additionally

, ai r pathwa y analysi s result s indicat e tha t win d erosion i s not a viabl e releas e mechanis m fo r th e lea d sla g piles
, includin g th e A V water-quenched an d sorte d fine s piles

. 

### Leachin g t o groundwate r i s als o no t a potentia l releas e mechanism

. Testin g i n subsla g materia l 

### indicate s tha t leachat e fro m sla g doe s no t contribut e t o elevate d metal s concentration s i n th e vados e zon e beneat h th e sla g piles

. Thi s conclusio n i s supporte d b y th e lac k o f acid-generatin g potentia l an d th e neutral-to-basi c p H o f th e sla g an d subsla g materials

. 6.5. 2 TERRESTRIA

L EXPOSUR E Terrestria l exposur e pathway s t o th e stockpile d fin e sla g ar e unlikel y t o be significant

. Th e sla g pile s d o no t offe r an y viabl e habita t o r sustenanc e fo r terrestria l receptors

. Althoug h terrestria l 

### receptor s (i.e.

, birds
, mammals ) coul d acces s th e sla g piles
, there i s n o habita t or foo d sourc e t o attract thes e receptors

. A s state d above
, win d erosion , leaching
, an d surfac e wate r runof f are no t considere d potentia l releas e mechanism s fo r th e sla g piles
, whic h considerabl y reduce s th e potentia l fo r terrestria l receptor s t o contac t sla g i n mor e attractiv e environs

.

Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 )
— o
. , JI298P:\3280-OI4\FINALROD\OU3ROD2.WP

D L)&-1J

### 7. 0 DESCRIPTIO

N O F ALTERNATIVE

S A brie f descriptio n o f th e thre e alternative s evaluate d i n th e Stockpile d Fin e Sla g F S fo r th e A V Smelte r Sla g Pil e (Terranext

, 1996a ) i s provide d below

. Al l alternatives presente d i n th e F S

wer e evaluate d agains t th e nin e criteri a describe d i n th e nex t section , an d the n compare d wit h

eac h o f th e othe r options

. Alternativ e 1 ; N o Actio n 

### Thi s alternativ e leave s th e stockpile d fin e sla g i n plac e wit h n o remediation
, engineerin g o r institutiona l controls
, or long-ter m maintenance

. Generally

, th e N o Actio n Alternativ e i s provide d fo r consideratio n a s a baselin e agains t whic h othe r technologie s ca n b e compared
, i n accordance wit h th e NCP

. N o Actio n i s protectiv e o f huma n healt h an d th e environment , an d i s considere d effectiv e becaus e n o complet e huma n o r ecologica l exposur e pathway s wer e identified

. However

, a site-wid e surfac e and groundwate r monitorin g progra m wil l b e develope d

onc e al l sourc e area s hav e bee n addressed

. Monitorin g wil l continue unti l EP A determine s tha t suc h monitorin g i s n o longe r necessar y t o ensur e tha t huma n healt h an d th e environmen t ar e protected

. D&RG W woul d conduc t an y required monitorin g a t th e stockpile d fin e sla g pile^ o ensur e tha t i t pose s n o threa t t o huma n healt h o r th e environment

. Thi s alternativ e i s technicall y feasibl e an d cost-effective

, sinc e i t doe s no t rel y o n an y technolog y an d ha s n o cos t (EPA

, 1996)

. Alternativ e 2 ; Institutiona l Control s Institutiona l control s involv e restrictin g acces s o r activitie s tha t coul d resul t i n huma n contac t wit h th e sla g o r increase th e potentia l fo r leachin g fro m stockpile d fin e slag

. Control s includ e fencing

, land-us e restrictions , o r dee d restrictions

. Additionally

, communit y awarenes s program s coul d b e implemente d t o aler t th e communit y t o an y physical ^ hazard s associate d wit h th e fin e slag

. Control s coul d b e implemente d separatel y o r i n combination

. Th e optio n considere d i s t o fenc e an d maintai n th e stockpile d fin e sla g locate d a t th e A V Smelte r Sla g Pile

, Fencin g woul d eliminat e th e potentia l direc t contact pathwa y wit h th e fin e sla g piles
, woul d be protectiv e o f huma n healt h an d th e environmen t becaus e n o complet e huma n o r ecologica l exposur e pathway s woul d exist (tha t is, childre n woul d no t hav e acces s t o th e piles)

, an d potentia l fo r releas e o f metal s i n leachat e fro m th e stockpile d fin e sla g woul d remai n minimal

. Fencin g woul d als o b e technicall y feasible

. Cost s associate d wit h fencin g ar e $163,97 0 wit h inspectio n an d maintenanc e cost s o f $8,44 3 for a 30-yea r perio d (EPA

, 1996)

. Alternatives ; Resourc e Utilizatio n Th e utilizatio n o f stockpile d fin e sla g a s a resourc e coul d involv e a numbe r o f activitie s and/o r processes

. A t present , although option s hav e bee n identified

, i t i s no t possibl e t o ascertai n i f o r whe n th e entir e volum e o f stockpile d fin e sla g coul d b e reused

. Tw o option s fo r th e resourc e utilizatio n (material s reuse ) wer e identifie d iirth e FS : 1 ) t o proces s th e sla g a s aggregat e fo r asphal t o r concrete , 2 ) t o us e sla g material s fo r stand-alon e materia l i n construction , suc h a s backfil l fo r roadbas e materia l o r pip e bedding

.
Recor d o f Decisio n Stockpile d Fin e Slag (O U 3 ) S129gP:\328<WI4\FINALROD\OU3ROD2.WP

D

### Resourc

e utilizatio n woul d b e protectiv e o f huma n healt h an d th e environmen t becaus e appropriat e environmenta l control s fo r particulate s emission s an d stor m wate r runof f woul d b e 

### require d t o contro l contaminan t releases

. Consideratio n mus t als o b e give n t o an y toxi c leachin g potentia l fo r th e fin e slag

. Resourc e utilizatio n ma y marginall y decreas e th e minima l metal s 

### concentration s i n th e stockpile d fin e sla g leachat e throug h overal l volume reduction

. However

, the effectivenes s an d implementabilit y o f thi s alternativ e woul d b e affecte d b y the regional 

### marke t deman d fo r th e material

. Effort s conducte d t o identif y market s hav e bee n unsuccessfu l t o date
, bu t a potentia l fo r futur e market s exists

. Therefore

, the EP A ha s determine d tha t thi s alternativ e shoul d b e include d a s a contingenc y wit h "N o Action " a s th e preferre d alternativ e 

### (EPA

, 1996)

. However

, resourc e utilizatio n o f the stockpile d fin e sla g i s onl y appropriat e i f i t i s 

### encapsulate d prio r t o it s use o r reuse

. Cos t effectivenes s i s hindere d b y th e distanc e th e sla g materia l i s locate d fro m a majo r marke t and th e cos t associate d wit h sortin g th e slag

. Cost for 

### us e o f the fin e sla g a s aggregat e i s estimate d a s a $1,120,00 0 los s afte r resale
, whil e the cos t fo r us e a s fil l material i s estimate d a s a $244,625 los s afte r resal e (EPA

, 1996)

.

Recor d o f Decision Stockpile d Hn e Sla g (O U 3 ) SI298P:\3280-OU\nNALROD\OU3ROD2.WP

D

### 8 . 0

SUMMAR Y O F COMPARATIV E ANALYSI S O F ALTERNATIVE S 

### Sectio n 300.430(e)(9 ) o f th e NC P require s tha t th e agencie s evaluat e an d compar e th e remedial 

### cleanu p alternatives base d o n th e nin e criteri a liste d below

. Th e firs t two criteria, (1 ) overal l protectio n o f huma n healt h an d th e environmen t an d (2 ) complianc e wit h applicabl e o r relevan t
an d appropriat e requirement s (ARARs ) i n Appendi x A

, ar e threshol d criteri a tha t mus t b e me t fo r th e Selecte d Remedy

. Th e Selecte d Remed y mus t the n represen t th e bes t balanc e o f th e 

### remainin g primar y balancin g an d modifyin g criteria

. 8 . 1 EVALUATION

AN D COMPARISO N CRITERI A
8.1. 1 THRESHOL D

CRITERI A
1

. Overal l protectio n o f huma n healt h an d th e environment addresse s whethe r o r no t a remed y provide s adequat e protectio n an d describe s ho w potentia l risk s pose d throug h

eac h pathwa y ar e eliminated
, reduced
, o r controlle d throug h treatment , engineerin g controls
, o r Institutiona l Controls

. 2

. Complianc e wit h ARAR s addresse s whethe r o r no t a remed y wil l compl y wit h identifie d federa l an d stat e environmenta l an d sitin g law s an d regulations

. 8.1. 2 PRIMAR Y BALANCIN G CRITERI A
3

. Long-ter m effectivenes s an d permanenc e refer s t o th e abilit y o f a remed y t o maintain reliabl e protectio n o f huma n healt h an d th e environment ove r time

. 4

. Reductio n o f toxicity

. mobilit y an d volum e throug h treatmen t refer s t o th e degre e tha t th e remed y reduce s toxicity , mobility
, an d volum e o f th e contamination

. 5

. Short-ter m effectivenes s addresse s th e perio d o f tim e neede d t o complet e th e remed y an d

an y advers e impac t o n huma n healt h an d th e environmen t tha t ma y b e pose d durin g th e constructio n an d implementatio n perio d unti l cleanu p goal s ar e achieved

. 6

. Implementabilit

y refer s t o th e technica l an d administrativ e feasibilitie s o f a remedy
, includin g th e availabilit y o f material s an d service s neede d t o carr y ou t a particula r option

. 7

. Cos t evaluate s th e estimate d capita l costs , operatio n an d maintenanc e costs , an d presen t wort h cost s o f eac h alternative

. 8.1. 3 MODIFYIN

G CRITERI A
8

. Stat e acceptanc e indicate s whethe r th e Stat e (CDPHE)

, base d o n it s revie w o f th e information

, concur s with
, opposes , o r ha s n o commen t o n th e preferre d alternative

.

Recor d o f Decision Stockpile d Fin e Sla g (O U 3 ) JI298P:\3280-OI4\FINALROD\OU3ROD2.WP

D

### 9

.

Communit y acceptanc e i s base d o n whether communit y concern s ar e addresse d b y th e Selecte d Remed y an d whethe r o r no t th e communit y ha s a preferenc e fo r a remedy

. 8 . 2 EVALUATIN

G TH E STOCKPILE D FIN E SLA G ALTERNATIVE S 

### Th e followin g i s a brie f summar y o f th e agencies evaluatio n

an d compariso n o f stockpile d fin e sla g alternatives

. Additiona l detail s evaluatin g th e alternative s ar e presente d i n th e FS

. Thi s 

### sectio n evaluate s th e performanc e o f th e stockpile d fin e sla g alternatives against th e nin e criteri a discusse d above
, an d compare s i t wit h the othe r possibl e options

. Informatio n fo r thi s sectio n w a s obtaine d fro m th e Fina l Stockpile d Fin e Sla g F S (Terranext

, 1996a)

. 

### 8.2. 1 OVERAL L PROTECTIO N O F HUMA N HEALT H AN D TH E ENVIRONMEN T This criterio n i s base d o n th e leve l o f protectio n o f huma n healt h an d th e environmen t afforde d 

### b y eac h alternative

. Al l o f th e alternative s are protectiv e o f huma n health

. N o complet e huma n 

### o r ecologica l exposur e pathways hav e bee n identified

. Base d upon th e chemica l compositio n o f the sla g an d soi l samplin g conducte d beneat h the slag
, the potentia l fo r releas e o f metal s i n 

### leachat e fro m th e stockpile d fin e sla g i s minimal

. Th e stockpile d fin e sla g has
, a t most , insignifican t non-poin t sourc e impac t o n wate r quality

. 

### Th e physica l feature s o f th e sla g pile s hav e remaine d relativel y unchange d fo r man y decades

. Tha t fact

, combine d wit h the determinatio n tha t the onl y potentia l releas e pathwa y i s throug h 

### leachate
, suggest s tha t th e statu s o f th e sla g i s no t likel y t o chang e i n th e nea r o r lon g term

. Therefor e al l thre e alternative s ar e protectiv e o f huma n healt h an d th e environment

. 8.2. 2 COMPLIANC E

WIT H APPLICABL E O R RELEVAN T AN D APPROPRIAT E REQUIREMENT S (ARARs ) 

### Thi s criterio n i s base d o n complianc e wit h chemical-
, location-
, an d action-specifi c ARARs

. ARAR s are presente d i n Appendi x A

. Al l o f th e alternative s mee t ARARs

. Groundwate r qualit y 

### i s a functio n o f th e activ e interchang e wit h surfac e wate r degrade d b y th e releas e o f mor e mobil e meta l specie s fro m the multitud e o f othe r contaminan t source s i n the vicinity

. The potentia l fo r 

### non-poin t sourc e metal s loadin g t o surfac e wate r fro m stockpile d fin e sla g leachat e i s minima l t o 

### nonexistent

. The us e o f institutiona l control s o n th e stockpile d fin e sla g wil l no t hav e an y effec t


### o n groundwate r quality

. Non-poin t source , Bes t Managemen t Practice s (BMP ) to-be-considere d 

### criteri a hav e bee n implemente d alon g th e sla g pile s contactin g Californi a Gulch

. 8.2 3 LONG-TER M EFFECTIVENES

S AN D PERMANENCE Thi s criterion i s base d o n th e magnitud e o f residual ris k an d adequac y an d reliabilit y o f controls

. N o Actio n i s a n effectiv e long-ter m alternative

. Th e onl y identifie d releas e pathwa y determine d 

### t o hav e an y potentia l t o contribut e t o huma n o r environmenta l risk s i s th e potentia l fo r metal s t o leac h fro m th e stockpile d fin e slag

. Base d upon subsla g sampling
, metal s hav e no t leache d an d wil l not leac h fro m the stockpile d fin e sla g i n concentration s tha t wil l hav e an advers e impac t o n 

### soils
, surfac e wate r o r groundwate r i n th e vicinity

. Base d upon th e hardnes s o f th e slag
, th e lac k Recor d o f Decision Stockpile d Fin e Sla g (O U 3 ) 5I298PA3280-OI4\FINALROD\OU3ROD2.WP

D

### o

f acid-generatin g potentia l an d th e absenc e o f significan t metal s i n soil s beneat h th e slag
, th e potentia l fo r exposur e t o metal s o f concer n foun d i n th e sla g i s unlikel y t o chang e i n th e lon g 

### term

. Institutiona l control s ca n b e effectiv e i n th e lon g term , bu t ar e no t permanent

. Fencin g require s inspections , maintenance an d communit y awareness , an d mus t b e renewe d o r replace d periodically

. Resourc e utilizatio n represent s a reliabl e alternativ e whic h use s know n 

### technologies
, limite d onl y b y th e regiona l marke t deman d for th e stockpile d fin e slag

. Resourc e utilizatio n wil l no t hav e a dramati c effec t o n th e residua l risk
, a s th e pre-resourc e utilizatio n risk s ar e minimal

. 

### 8.2. 4 REDUCTIO N O F TOXICITY

, MOBILITY

, O R VOLUM E THROUG H TREATMEN T 

### Thi s criterion i s base d o n th e treatmen t proces s used ; th e amoun t o f contaminatio n destroye d o r 

### treated ; th e reductio n o f toxicity , mobility
, an d volume; th e irreversibl e natur e o f th e treatment ; th e typ e and quantit y o f residual s remaining; and th e statutor y preferenc e for treatment

. Institutio n control s an d N o Actio n d o no t furthe r reduc e th e ver y limite d toxicit y o r mobilit y o f metal s o f concer n i n the stockpile d fin e slag

. I n the absenc e o f complet e exposur e pathways
, ther e i s n o indicatio n tha t toxicit y an d mobilit y o f hazardou s substance s i n th e sla g pos e a huma n healt h risk

. Fro m a land-us e perspective , th e sla g volum e i s no t a n issu e a s tourist s com e specificall y t o observ e histori c minin g practices

. Implementatio n o f institutiona l control s o r the N o Actio n alternative
, however
, wil l not reduc e the volum e o f the fin e sla g foun d a t the site

. Ove r time , reus e coul d reduc e th e ver y limite d potentia l toxicit y an d potentia l mobilit y o f th e stockpile d fin e slag

. Fro m a land-us e perspective , th e chang e i n th e tota l volum e o f al l type s o f sla g wil l no t b e significan t i f onl y th e stockpile d fin e sla g i s utilized

. 8.2.5 SHORT-TER M

EFFECTIVENES

S Thi s criterio n i s base d on th e degre e o f communit y an d worke r protectio n offered

, th e potentia l 

### environmenta l impact s o f th e remediation
, an d th e tim e unti l th e remedia l action i s completed

. N o actio n an d institutiona l control s d o no t creat e additiona l ris k t o th e Leadvill e communit y durin g implementation

. Fo r institutiona l controls
, worker s an d th e communit y ca n b e adequatel y an d reliabilit y protecte d i f fencin g wer e t o b e installed

. Resourc e utilizatio n ca n als o b e implemente d wit h n o additiona l ris k t o th e Leadvill e community

. Worker s an d th e communit y ca n b e adequatel y an d reliabl y protecte d fro m fugitiv e particulate s and change s i n storm-wate r drainag e whe n the stockpile d fin e sla g i s utilized

. 

### 8.2. 6 IMPLEMENTABILIT

Y 

### Thi s criterion i s base d o n th e abilit y t o perfor m constructio n an d implemen t administrativ e actions

. N o Actio n i s technicall y feasibl e a s i t doe s no t rel y o n an y technology

. A s th e statu s quo , n o actio n i s implementable

. Recor d o f Decisio n Stockpile d Fin e Sla g (OU 3 ) 5l298P:\32«M)M\FINALROmOU3ROD2.WP

D

### Institutiona l

control s ar e technicall y feasible

, a s reliabl e fencin g ca n b e procure d an d installe d 

### readil y b y loca l contractors

. Land-use restriction s woul d requir e actio n b y eithe r th e Lake Count y Commissioner s or th e Leadvill e Tow n Council

. Therefore

, becaus e furthe r actio n i s 

### needed b y a thir d party , th e potentia l o f implementabilit y o f land-us e restrictions canno t b e predicted

. 

### Resourc e utilizatio n i s als o technicall y feasibl e bu t ther e ar e unknown s a s t o th e marketabilit y o f the resource

. Deman d fo r the stockpile d fin e sla g wil l b e dependan t o n a numbe r o f factors

, includin g bu t not limite d to , the leve l o f constructio n activit y i n the vicinit y o f Leadville

. 8.2. 7 COS T Alternativ e 1 : N o Actio n 

### A s ther e ar e n o cost s associate d wit h N o Action

, i t i s th e mos t cos t effectiv e alternative

. Alternativ e 2 : Institutiona l Control s Institutiona l control s involv e fencin g and maintenance o f the stockpile d fin e sla g locate d at the 

### A V Smelte r Sla g Pile

. Fencin g th e A V pil e woul d hav e presen t valu e capita l an d labo r cost s o f 

### $161,00 0 an d inspectio n an d maintenanc e cost s o f $8,50 0 t o inspec t an d maintai n ove r a 30-yea r perio d indicate d i n th e summar y i n Tabl e 1

. Alternativ e 3 : Resourc e Utilizatio n Resourc e utilizatio n doe s no t presentl y appea r t o b e a cost-effectiv e optio n eve n i f marke t demand s fo r th e materia l ar e identified

. Effort s conducte d t o identif y market s hav e bee n unsuccessfu l t o date

. Th e options considere d ar e 1 ) t o proces s sla g fo r us e a s a concret e o r asphal t aggregat e i n construction , an d 2 ) t o utiliz e sla g material s fo r a stand-alon e materia l i n construction , suc h a s a backfil l o r pip e bedding

. 

### Th e cos t effectivenes s o f thes e option s i s hindere d b y th e distanc e th e sla g materia l i s locate d fro m a majo r marke t an d th e cos t associate d wit h sortin g th e slag

. Cos t estimate s an d a cos t summar y ar e include d i n Tabl e 1

. Estimate s hav e bee n provide d fo r us e o f the fin e sla g fo r aggregat e ($1,120,00 0 los s afte r resale ) an d fo r us e i n fil l materia l ($244,62 5 los s afte r resale)

. 8.2. 8 STAT E ACCEPTANC E Th e Stat e ha s bee n consulte d throughou t thi s process an d concur s wit h th e Selecte d Remedy

. 

### 8.2. 9 COMMUNIT

Y ACCEPTANC E Publi c commen t o n th e RI/F S an d Propose d Pla n wa s solicite d durin g a forma l publi c commen t 

### perio d extendin g fro m Septembe r 2 7 t o Octobe r 28,1996

. I t i s assume d tha t th e communit y i s 

### generall y supportiv e o f EPA' s N o Actio n alternativ e sinc e n o comment s wer e generate d durin g Recor d o f Decisio n Stockpile d Fin e Sla g <O U 3 ) 5I29SP:U2804I4\HNALROD\OU3ROD2.WP

D

### the

forma l publi c commen t period

. I n addition
, onl y two ora l comment s wer e raise d durin g the publi c meetin g hel d Octobe r 3,1996

. Thes e comment s wer e i n regar d t o the volum e o f the fin e sla g pil e an d th e natur e o f th e soi l beneat h th e Harriso n St

. sla g pile
, whic h i s no t relevant t o thi s ROD

. 8.2.1 0 SUMMAR Y 

### Th e F S use d a comparativ e analysi s t o qualitativel y evaluat e th e performanc e o f eac h alternativ e i n relatio n t o eac h specifi c evaluatio n criterion

. Th e purpos e o f thi s comparativ e analysi s i s t o identif y th e advantage s an d disadvantage s o f eac h alternativ e relativ e t o on e anothe r so tha t ke y tradeoff s coul d b e identified

. 

### A gri d compariso n metho d wa s use d t o ran k th e alternative s an d thei r attainmen t relativ e t o th e NC P criteri a se t fort h i n th e SFS

. Alternative s wer e ranke d o n a scal e o f 1 t o 5 , wit h 5 bein g th e highes t attainmen t o f th e criterion

. Tota l score s fo r eac h alternativ e were : Alternativ e 1 : N o Actio n a t 41 ; Alternativ e 2 : Institutiona l Control s a t 3 9 ; an d Alternatives : Resourc e Utilizatio n a t 36

. Tabl e 2 provide s a gri d compariso n metho d t o ran k th e alternative s an d thei r attainmen t relativ e t o th e followin g criteria

. • Protectio n o f Huma n Healt h and the Environmen t - Al l thre e alternative s ar e protectiv e o f huma n healt h an d th e environment

. • Attainmen t o f ARAR s - Al l three alternative s attai n ARARs

. • Long-Ter m Effectivenes s - Al l thre e alternative s hav e simila r long-ter m effectiveness

. Reus e o f th e stockpile d fin e sla g woul d marginall y reduc e th e residua l ris k because o f volum e reduction

. Non e o f th e alternative s ar e subjec t t o technolog y failur e fro m ag e o r wea r an d tear

. • Reductio n o f Toxicity

, Mobilit y o r Volum e - Non e o f th e thre e alternative s reduc e th e toxicit y an d mobilit y o f metal s o f concer n foun d i n th e fin e slag

. • Short-Ter m Effectivenes s - Al l three alternative s ca n b e implemente d i n a manne r whic h protect s th e Leadvill e communit y an d th e worker s implementin g th e remedy

. Th e N o Actio n alternativ e eliminate s disturbance s o f th e fin e grai n sla g an d require s n o workers

. • Implementabilit

y - Al l thre e alternative s ar e implementable

. Dee d restriction s ar e i n effect

. Lan d us e restriction s ma y not b e implementabl e fro m and administrativ e perspectiv e a s the y requir e approva l b y th e Lak e Count y Commissioners

. Reus e require s tha t ther e b e a commercia l marke t or internal nee d for th e stockpile d fin e sla g which
, a t thi s time , i s uncertain

. • Cos t - N o Actio n i s th e mos t cost-effectiv e approac h t o meetin g th e remedial actio n objective s an d attainin g ARARs

. Ther e ar e essentiall y n o cost s associate d wit h thi s remedia l option

. • Stat e Acceptanc e - CDPH E ha s bee n consulte d throughou t th e RI/F S process

. • Communit y Acceptanc e - Th e communit y has bee n consulte d throughou t th e RI/F S 

### process

. Selectio n o f th e N o Actio n alternativ e wa s base d o n thi s analysis

.
Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5I29SP:\328<M>U\FINALROD\OU3ROD2.WP

D

### 9. 0 SELECTE D REMED Y 

### Base d upo n consideratio n o f CERCL A requirements , th e detaile d analysi s o f alternatives
, an d publi c comments , EP A ha s determine d tha t th e N o Actio n alternativ e presente d i n th e Propose d Plan

, wit h n o modifications

, i s th e appropriat e remed y fo r th e stockpile d fin e sla g a t th e A V 

### Smelte r Slag Pil e o f OU 3 withi n th e Californi a Gulc h Superfun d Site

. Th e N o Actio n alternativ e leave s the stockpile d fin e sla g i n it s existin g conditio n wit h no contro l o r cleanu p planned

. The N o Actio n alternative
, a s describe d i n th e Propose d Plan

, include s a contingenc y fo r futur e 

### utilizatio n o f th e slag
, i f i t i s encapsulate d prio r t o it s us e o r reuse

. Th e N o Actio n alternativ e i s protectiv e o f huma n healt h and th e environment , and i s considere d effectiv e becaus e n o complet e huma n or ecologica l exposur e pathway s wer e identifie d an d becaus e the potentia l fo r releas e o f metal s i n leachat e i s minimal

. Base d o n subsla g sampling
, metal s hav e not leache d and wil l not leac h fro m the stockpile d fin e sla g i n concentration s tha t wil l hav e a n advers e impac t o n soils
, surfac e water , o r groundwate r i n th e area
. Slag hardness
, 

### th e lac k o f acid-generatin g potential
, an d th e absenc e o f an y significan t metal s beneat h th e sla g 

### als o indicat e tha t th e potentia l fo r exposur e t o metal s o f concer n foun d i n th e sla g i s unlikel y t o chang e i n the lon g term

. Thi s alternativ e i s technicall y feasibl e and cos t effective

, since i t doe s no t rel y o n an y technolog y an d ha s n o cost

. Resourc e utilizatio n woul d onl y implemente d i f futur e regiona l marke t deman d exist s fo r th e material

. Encapsulatio n o f th e fin e sla g ensure s tha t th e contingenc y remed y i s als o protectiv e o f huma n healt h an d th e environment

. Encapsulatio n can includ e th e us e o f th e fin e sla g i n 

### concret e o r asphal t aggregate ; o r a s roa d base
, backfil l o r othe r constructio n material a s lon g a s th e fin e sla g i s chemicall y boun d o r physicall y separate d fro m an y exposur e scenari o b y a barrie r consistin g o f anothe r material

. Dus t suppressant s t o control paniculat e emission s an d bes t managemen t practices t o contro l stormwate r runof f woul d als o b e employe d t o contai n contaminant release s durin g implementatio n o f th e contingenc y remedy

.

Recor d o f Decisio n Stockpile d Fin e Sla g (OU 3 ) 5I298P:\3280-OI4\FINALROD\OU3ROD2.WP

D10. 0 STATUTOR Y

DETERMINATION

S 

### Unde r CERCL A Sectio n 121 , EP A mus t selec t a remed y tha t i s protectiv e o f huma n healt h an d th e environment ; tha t complie s wit h ARARs ; i s cos t effective ; an d utilize s permanen t solutions
, an d alternativ e treatmen t technologies
, o r resourc e recover y technologie s t o th e maximu m exten t practicable

. I n addition
, CERCL A include s a preferenc e fo r remedie s tha t includ e treatment 

### whic h permanentl y and significantl y reduce s the volume
, toxicity , o r mobilit y o f hazardou s waste s a s a principa l element

. However

, th e Selecte d Remedy

, N o Action

, doe s no t satisf y th e statutor y preferenc e for treatmen t a s a principa l elemen t o f th e remedy

. Treatmen t wa s considere d unnecessar y a s th e Selecte d Remed y i s protectiv e o f huma n healt h an d th e 

### environment

. Th e followin g section s discus s ho w th e Selecte d Remed y meet s statutor y requirements

. 10. 1 PROTECTIO N

O F HUMA N HEALT H AN D TH E ENVIRONMEN T The selecte d remed y i s protectiv e o f huma n healt h and the environmen t becaus e 1 ) n o complet e huma n o r ecologica l exposur e pathways wer e identifie d an d 2 ) metal s hav e no t leache d an d wil l

no t leac h fro m th e stockpile d fin e sla g tha t wil l hav e an adverse impac t on soils
, surfac e wate r or groundwate r i n th e area
.

• Becaus e th e estimate d actio n level s fo r recreationa l land-us e scenario s ar e significantl y abov e curren t surficia l soi l concentration s for bot h lead and arsenic , ther e appear s t o b e relativel y littl e uncertaint y i n the conclusio n tha t curren t surfac e soil s d o not pos e unacceptabl e ris k level s t o recreationa l sit e visitor s anywher e withi n th e O U boundarie s (EPA

, 1995b)

. I n addition
, th e A V Smelte r Sla g Pil e are a i s situate d i n a n are a presentl y zone d a s industrial/minin g an d i s no t considere d a recreationa l us e are a (EPA

, 1996)

. Ther e ar e n o curren t worke r exposur e pathways t o th e stockpile d fin e slag

. Th e Selecte d Remed y provide s a contingenc y fo r resourc e utilization
, whic h ma y b e undertake n i n th e future

. T h e EP A has determine d tha t resourc e utilizatio n o f th e stockpile d fin e sla g i s onl y appropriat e i f i t i s encapsulate d prio r t o it s us e o r reuse , t o dete r th e potentia l releas e o f airborn e particulate s an d eliminat e potentia l ris k associate d wit h resourc e utilizatio n activities

. Dus t suppressant s t o contro l particulat e emission s an d bes t management practice s t o control stormwate r runof f woul d als o b e employe d t o contai n contaminan t release s durin g implementatio n o f th e contingenc y remedy

. The soi l actio n leve l fo r lea d base d o n commercial/industria l

exposur e t o soi l an d dus t ranged fro m a s lo w a s 2,20 0 part s pe r millio n (ppm ) t o a s hig h a s 19,10 0 pp m wit h centra l tendenc y value s i n th e 6,10 0 t o 7,70 0 ppm range
. Lea d concentrations i n soil s i n and aroun d th e sla g pile s (maximu m lead concentratio n o f 79 4 ppm ) wer e wel l belo w the lea d actio n leve l (EP A 1996)

. 

### Soi l actio n level s fo r arseni c base d o n commercial/industria l

exposur e t o soi l an d dus t range d fro m a s lo w a s 33 0 pp m t o a s hig h a s 1,300 ppm , wit h centra l tendenc y value s i n th e 61 0 t o 69 0 pp m range
. Arseni c concentrations i n soil s i n an d aroun d th e sla g pile s (maximu m arseni c concentratio n o f 5. 7 mg/kg ) wer e wel l belo w th e lowest arseni c action level

. Recor d o f Decision Stockpile d Fin e Sla g (O U 3 ) 5 129SP:\3280-OI 4\FINALROD\OU3ROD2.WP

D10.

2 COMPLIANC E

WIT H ARAR s 

### Th e Selecte d Remed y wil l compl y wit h al l ARAR s identifie d i n Appendi x A t o thi s ROD

. N o waive r o f ARAR s i s expecte d t o b e necessary

. 10. 3 COS T EFFECTIVENES

S 

### Sectio n 300.430(f)(ii)(D ) o f th e NC P require s evaluatio n o f cos t effectiveness

. Th e Selecte d 

### Remed y i s cos t effectiv e becaus e i t ha s n o cost

. 10. 4 UTILIZATIO

N O F PERMANEN T SOLUTION S AN D ALTERNATIV

E TREATMEN T TECHNOLOGIE S

(O R RESOURC E RECOVER Y TECHNOLOGIES

! T O TH E MAXIMU M EXTEN T POSSIBL E N o remedia l actio n i s necessar y t o ensur e protectio n o f huma n healt h an d the environment

. The contingenc y allow s fo r resourc e recover y i f supporte d b y regiona l marke t demand

. 10. 5 PREFERENC

E FO R TREATMEN T A S A PRINCIPA L ELEMEN T 

### Treatmen t o f th e stockpile d fin e sla g a t th e A V Smelte r Sla g Pil e wa s no t considere d becaus e th e N o Actio n alternativ e i s protectiv e o f huma n healt h an d th e environment

.

Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 5IW8P:\3280-OI4\FINALROD\OU3ROD2.WP

D

### 11. 0

DOCUMENTATIO

N O F SIGNIFICAN T CHANGE S 

### T h e Propose d Pla n fo r stockpile d fin e sla g a t th e A V Smelte r Sla g Pil e wa s release d fo r publi c commen t i n Septembe r 1996

. Th e Propose d Pla n identifie d Alternativ e 1 , N o Action

, a s th e 

### preferre d alternative
, wit h th e contingenc y tha t resourc e utilizatio n ma y b e undertake n i n th e future

. Resourc e utilizatio n o f th e stockpile d fin e sla g woul d onl y b e appropriat e i f i t i s encapsulate d prio r t o it s us e o r reuse

. N o comment s wer e receive d durin g th e publi c commen t 

### period

. Subsequently

, EP A determine d tha t n o significan t change s t o th e remedy
, a s i t wa s originall y identifie d i n th e Propose d Plan

, wer e necessary

.

Recor d o f Decisio n Stockpile d Fin e Sla g (O U 3 ) 51298P:\3280-0 1 -(\FINALROD\OU3ROD2.WP

D

### 12. 0 REFERENCE S Morriso n Knudse n Corporatio n (MK)

. 1992

. Report fo r Lea d Sla g Pil e Remedial Investigatio n a t th e Californi a Gulc h Sit e Leadville

, Colorado

, prepare d fo r Denve r & Ri o Grand e Wester n Railroad

. Decembe r 11

. Terranext

. 1996a

. Fina l Stockpile d Fin e Sla g Feasibilit y Study

, prepare d fo r Denve r & Ri o Grand e Wester n Railroad

. Ma y 13

. Terranext

. 1996b

. Wor k Pla n Consolidatio n o f Fin e Slag

. Prepare d fo r Denve r & Ri o Grand e Wester n Railroad

. November

. 12

. U.S

. Departmen t o f Commerce

. 1990

. Selected Population an d Housing Characteristics. Burea u o f th e Census

. U.S

. Environmental Protectio n Agenc y (EPA)

. 1997

. Ecologica l Ris k Assessmen t fo r th e Terrestria l Ecosystem

. Californi a Gulc h NP L Superfun d Site

, Leadville

, Colorado

. Prepare d b y Ro y F

. Weston

, Inc.

, January

, 1997

. U.S

. Environmenta l Protectio n Agenc y (EPA)

. 1996

. Propose d N o Actio n Pla n fo r Stockpile d Fin e Slag

, Arkansa s Valle y Smelte r Sla g Pile

, Californi a Gulc h Superfun d Site

, Leadville

, 

### Colorado

. September

. U.S

. Environmenta l Protectio n Agenc y (EPA)

. 1995a

. Draf t Fina l Finding s o f Meta l Speciatio n Investigation s a t th e Californi a Gulc h NP L Site

, Prepare d b y Joh n W

. Drexle r an d Ro y F

. 

### Weston

, Inc.

, Octobe r 1995

. U.S

. Environmental Protectio n Agenc y (EPA)

. 1995b

. Baselin e Huma n Healt h Ris k Assessmen t fo r th e Californi a Gulc h Superfun d Sit e - Par t A
- Risk s t o Resident s fro m lea d 

### prepare d b y Ro y F

. Weston

, Inc.

, Draf t fina l Novembe r 6,1995

. U.S

. Environmenta l Protectio n Agenc y (EPA)

. 1995c

. Baselin e Huma n Healt h Ris k Assessmen t fo r th e Californi a Gulc h Superfun d Sit e - Par t C

- Evaluatio n o f Recreationa l an d Worke r Scenario s prepare d b y Ro y F

. Weston

, Inc.

, Apri l 17,1995

. 

### U.S

. Environmental Protectio n Agenc y (EPA)

. 1995d

. Fina l Baselin e Aquati c Ecologica l Ris k Assessment

. Californi a Gulc h NP L Site

. Prepare d b y Ro y F

. Weston

, Inc.

, September

, 1995

. U.S

. Environmenta l Protectio n Agenc y (EPA)

. 1991

. Preliminar y Huma n Healt h Baselin e Ris k 

### Assessmen t fo r th e Californi a Gulc h NP L Site

, Leadville

, Colorado

. Prepare d b y Ro y F

. Weston

, Inc

. fo r th e U.S

. EPA

, Decembe r 1991

.

Recor d o f Decision Slockpile d Fin e Slag (O U 3 ) 5129gP:\3280-OI4\FINALROD\OU3ROD2.WP

DU.S

. Environmenta l Protectio n Agenc y (EPA)

. 1989

. Draft Phase I I Remedial Investigation Technical Memorandum, 1986-1987, California Gulch Site, Leadville, Colorado, U.S. EPA, 

### Prepare d b y CH2 M Hill

, Ma y 1989

. Woodwar d Clyd e Consultant s (WCC)

. 1993

. Draft Terrestrial Ecosystem Evaluation Report, California Gulch Site, Leadville, Colorado. April

.

Recor d o r Decisio n Stockpile d Fin e Sla g (O U 3 ) 51298P:\3280-014\F!NALROD',OU3ROD2

.

WP D

### FIGURE S

### CALIFORNIA GULCH SUPERFUND SITE

C O M FEDERA L PROGRAM S CORPORATIO N • ! dn » Pun * » McK M h*

. 

### GENERA L LOCATIO N MA P CALIFORNI A GULC H SUPERFUN D SIT E LEADVILLE

, COLORAD O Figur e 1Operabl e Unit s Californi a Gulc h Supcrfun d Sit e Leadville

, Colorad o Traiisrxiriatio n am i Cultura l Feature * HlWSuperfun d and/o r other I'RP' x O U I
- Ya k Tunnel/Waie r Treatmen t Plant O U 2 -Malt a Culch Fluvia l Tailin g xnlvill c Coq > Mill/Malt a Gulc h Tailin g O H 3 -IXVRC i Slo g Piles/Railroa d 1-inrmenl / Rnilrood Ynt l O U 4 -Uppe r Californi a Ciulcl

. CXI 5 -Aiuro i Smellcrs/Sla|;/Mil l Sue * O I K -Slu r Oilch/IVnnis c IXimr X Stra y llon r CiulcWlivnn s (iiilch OIF 7 -Apach e Toilin g ImpnuiKlmcnt s C X W -I m m Californi a Gulc h -RcsiJcnlia l Populjlc d Arra s CXJI O -Orego n (Julc h CHM I -Arkansa s Rive r Valle y Flutxlplai n OUI2-Sit c Wate r Qualit y i-ulur e I.labilit y Dclerminatiti n Kesurrection-A.iarc o Join t Ventur e RI/K S Sluil y Are a Boundar y Containin g lluvin l Tailin g Operabl e Unit s an d Area s o f Responsibilit y Tmispurtaiion

. Cultura l l-'caliira

. an d Hydrograph y fro m CompuSys t Inc.

. 1992

. T« ! Wmcl c Koc k Tailin g Impoundment s Sla g Smelte r Location s .ii.iL ImpcHiiKlnK-nis

. Wan e Ruc k Pile*

, an d Sla g Pile s compile d b y Ro y f

. Western

. Inc.

. fro m StcfTan

. <XH.W M ani l Kirste n (SRK)

. I9»9; an d Wnl« h an d Associates

. 1993

. Huvia l area s fro m Woodwar d -Clyd e
..... . CwwiiKan'tsiT w Snwltc r iVcalion s h y ASARCO

. 1991

. Stud y Area

. Operabl e Unit

, an d Wor k Are a lloundaria del'ma l h v 1 : .I'A

. 

### CALIFORNI A GULC H SUPERFUN D SIT E A N D OPERABL E UNIT S LEADVILLE

, COLORAD O C OM FEDERA L PROGRAM S CORPORATION • t*»M« 7 M COT * dm**

- » M<K« * ht

.DATU

M c «75i C DA1U

H •755. 0

040 0 0+7 1 OV- 1 DATU

M iTsao

.

0+0 0 0+ M OV- 2 S DATU M MOQ. O

0+0 0 0+ M OV- 3 DATU M •800. 0
OWRSI7J B AVERAG E ANGL E C F RPOS E • SL T 0+0

0 0+5 3 SF- 1 DATUM

- NOS.O Q 

# i

0+000+4 4 SF- J 0+0

0 0+2 8 sr- 3 DATU

M •810.0

.

SORTC D FINE S AVERAG E ANGL E C F REPOS E • 311 * 0+000+4 1

BAL- ! BATUM i

•810. 0

0+0 0 0+4 8 BM.- 2 0+0

0 0+5 1 BAL- 3 BALLAS T AVERAG E ANGL E O F REPOS E

- 28.4 *

DATU M 6815.0 , DATU

M •7M. O

0+0 0 0+2 7 W H DATU

M 

## - / I

0+0 0 0+5 1 DATU M
-

0+0 0 0+6 5 WO- 3 DATUM

-

•765.0 o

0+000+4 0 UN- 1 DATU

M •7W. O

0+0 0 0+4 7 UN- 2 0+0

0 0+4 3 UN- 3 OUTLIN E OF HISTOR I SUPERIMPOSE D O N CUR l FO R READE R 1 C (1956 ) PIL E IIENTSURFA C MPARISIO N WATER-OUENCHE D FINE S AVERAG E ANCL E O F REPOS E

- 31. r UKPROCESSC

D AIR-COOLE D AVERAG E ANGL E O F REPOS E

- 27J *

N 511,00 0

N 510,50 0

C O ARE A VOL l CALCUL A W X 20 U^««^ k C nqftf i 3 y ~~SOUAR F ~~W

8 FEE T 1 TA W

480,34 1 1*

3

e».S3 6 1 C 102.78 6 9 1 37

. I M 4 3 354,97 9 i IS O

1 40,67 4 IS

. 44.79 0 2

3 698.30 0 ;

mmmmmmmmm ••••

< 1,799.12 6 TOTAL

, 42 2 JL/-WT W M E COON GRI D 100 2 C



# - / • \

m \ OS 3 /

30 4 .33 7 ,02 0
.13 1 U \mmmm .56 9 ISURt D /• "



## 1 •«SO- " 

## & & 

## # f $ 

# '/. 

# s

• v' . ~f~=^ WM .V.V.V J £7

. ^XKXJI.

! + ^ 4 

# I I

OV- 3 

### LEGEN D i
2 SURFAC E CONTOU R INTERVA L A D D 9000 T O ELEVATIO N CONTOUR S KUG D curator s (AIR-COCUD ) •CUJ'SIA O UKPROGESSC D AIN-COOU D OVERSia D (AIR-OOOUD ) > J \f f SORTC O FINE S (AIN-COOUD ) O/B * UNPWXXSSt D WATCT-OJEKCHO

J FINE S MIXE D UNPROCESSE O AIR-COOUD/trATER-aUDCHC

D BU1AST-SIZE D VCNCC R O F AIR-00003 ) SLA C ANO £ O F REPOS E CALCULATIO N SECTIO N SECTIO N IKNnnCATIO N

OV- 3

O

C OM

FEDERA L PROGRAM S CORPORATIO N • MMdv y « l CM* Pmii r » MIN M In

. 

### GENERA L LOCATIO N MA P 

### CURREN T SURFACE AREA S VOLUME S AN D ANGLE S O F REPOS E ARKANSA S VALLE Y SLA G PIL E LEADVILLE

, COLORAD O Figur e

## LEGEND

. ! • SURFAC E CONTOU R INTERVA L ELEVATION S AR C VALU E PLU S 0.00 0 FEE ! WGLDC D OUTCROP S (AIR-COOLED ) •OUTSIA O ovCTsin n (AIR-COQUD ) > j t/ r UNPROCESSE D AIB-COCU D SORTED FINE S (AIR-COOUD ) O/ T UNPnOCCSSE D WATCT-CUCTCHE D

FING S .COOUO/WAT£R-OUCNO€ 0

GRASSE S BAUASTSin D VtMEE R O F AIR-COOU D SLA G A AVD10 1 SAWP U LOCATIO N AN D IDENTIFICATIO N

C O M FEDERA L PROCRAU S CORPORATIO N

« MMMw y « f COT * fern * » M«K M Me

. 

### GENERA L LOCATION S A N D RECONNAISSANC E

INFORMATIO N ARKANSA S VALLEY SLA G PIL E LEADVILLE

, COLORAD O Figur e 4TABLE STABLE I ESTIMATES OF COSTS FOR REMEDIAL ALTERNATIVES OPTION I

INSTITUTIONAL CONTROLS (I) FENCE THE AV FINE SLAG PILE CALIFORNIA GULCH ARKANSAS VALLEY SLAG PILE LEADV1LLE ALTERNATIVE: HEM: DIRECT CAPITAL COSTS: (Includes Labor, Equipment and Materials, Unless Otherwise Noted) COSTS COMPONENT
1. Mobilize

Materials
2. Office/Storage

trailer (S'lSO')
3. Earthwork

(JSO hpbulldoser)
4. Utilities Electric Phone Sanitary Station
i. Fence Materials Fencing Comer Post Braces Double Swing Gales Locks TOTAL DIRECT COSTS INDIRECT CAPITAL COSTS (K of Direct Capital Costs)
1. Engineering

and Design (10% of Capital Costs) 2. Contingency

Allowance (20% of Capital Cost) J. Other Indirect! Regulatory License/Permits (Sti of Direct Capital Costs) TOTAL INDIRECT COSTS PRESENT VALUE OF OPERATION AND MAINTENANCE COSTS Annual Inspection and maintenance TOTAL COSTS ASSUMPTIONSKOMMENTS: UNIT Lump Lump Cubic Yards Month Month Month Lineal Feet Each Each Opening Each QUANTITY

I I 5,00 0 / / /

3.300 SO 106 3 3 UNIT COSTS S2.700.00 $1.800.00 S2.SO SI. 300.00 S6.00.00 S90.00 Slf.00 S9S.OO 5)5.00 5970.00 SIS.OO TOTAL

CAPITAL COSTS S2.700 SI.800 S12.SOO SI.300 S600 S90 W/.SO O S-I.7SO S3.7JO S2.9IO Hi

Year 30 S7SO.OO SJIS.20S

SII.S2I S23.MI SS.760 S-16.082 S8.J43 SI63.970

1. Eight (8) hods of fencing materials will be hauled using flatbed trailers. 2. Includes mob and demob, let-up and leveling. leat^down and monthly leasing charge. 3. Earthwork

consists of consolidating sorted and walei^quenchedfme slags before fencing: no mob or demob, onsile contractor utilized. •I. Fencing Is 6 go. Galvanized wire, 6' high, no barbed wire. S. Gales are 20'wide and include posts and hardware. Source : Terranext

, 1996 a

P:\32SO-OI4\WP\RODVTABLE

I .WP DCALIFORNIA

GULCH LEADV1LLE, COLORADO ALTERNATIVE: ITEM TABLE I (Continued) ESTIMATES OF COSTS FOR REMEDIAL ALTERNATIVES

RESOURCE UTILIZATION (I) FINE SLAG ADDITIVE MATERIAL IN CONSTRUCTION Aggregate for concrete or asphalt, add/tin to building materials, additive to grout, concrete and slurry formations)

UNIT Cubic Yards Cubic Yards QUANTITY

190.000 190,000 DIRECT CAPITAL COSTS (Includes Labor, Equipment and Materials. Unless Otherwise Noted) COMPONENT
1. Rescreea material
2. Load and haul TOTAL DIRECT COSTS INDIRECT CAPITAL COSTS flt of Direct Capital Costs)
1. Engineering and Design (I OH oj Capital Costs) 2. Contingency Allowance (20X of Capital Cost) 3. Other Indincts Regulatory License/Permits (5% of Direct Capital Costs) TOTAL INDIRECTCOSTS CREDITS FROM SALE OF PRODUCT MATERIAL
1. Additive 2. Backfill Material TOTAL CREDIT TOTAL COSTS/PROFIT(i) ASSUMPTIONS/COMMENTS:
1. Ay fine slag pile volumes are usedlo compute costs. 2. 90% of material wilt be suitable for use as additive. 3. IOM of material used as backfill material. •/

. N o operations an d maintenance costs ar e necessary over a n extended period. S. Credits from sale of product material have been reduced to reflect transportation costs to a major market. Source : Terranexl

, 1996 a COST S SS6S S3.25 TOTAL

COSTS Sl.07f.200 S6I7.500 SI. 696.700

5169.670 S339.HO S84.835
5593.845 Cubic Yard Cubic Yard 171.000

19.000 56.50

S3. 10 5(1.111.500) 5(58.900) 5(1.170.400) SI.I20.H5

P:\32SO-OM\WF\ROD\TABLEI.WP

DTABLE I (Continued) ESTIMATES OF COSTS FOR REMEDIAL ALTERNATIVES CALIFORNIA GULCH LEADVJLLE. COLORADO ALTERNATIVE: ITEM: RESOURCE UTILIZATION (1) USED AS STAND ALONE MATERIAL IN CONSTRUCTION (Fill material) DIRECTCAPITAL COSTS: (Includes Labor, Equipment and Materials. Unless Otherwise Noted) COMPONENT UNIT

QUANTITY I. Load and Haul Cubic Yards 190.000 TOTAL DIRECT COSTS INDIRECT CAPITAL COSTS (K of Direct Capital Costs)
1. Engineering and Design (lotto/Capital Costs) 2. Contingency Allowance (20K of Capital Cost) 3. Other Indirecls Regulatory Ucenst/Ptrmits (i% of Direct Capital Costs) TOTAL IND1RECTCOSTS TOTAL COSTS (Direct plus Indirect) CREDITS FROM SALE OF PRODUCT MATERIAL I. Backfill Material Cubic Yard 190.000 TOTAL CREDIT TOTAL COSTyPROFlTfS) ASSUMPTIONSKOMMENTS:
1. Ay Fine slag volumes are used to compute costs. 2. 100% of material will be suitable Jor use as backfill. 3. Load and haul is for conveyance to suitable rail loading dock. •I. Credits from sale of product material have been reduced due to transportation costs to a major market. S. Annual Operations and Maintenance costs are included in estimate. Source : Tenanott

, I996 a CAPITAL COSTS S3.2S

53.10 TOTAL

COSTS
5617.500 t6l7.SOO

S61.7SO SI23.SOO S30.87S
5216.125 5833,625 5(589.000) S(S89.000) S2U.625

P:\328WJ14\WIMIOD\TABLE 1

.WP D

### TABL E 2 

### GRI D COMPARISO N METHO D FO R ALTERNATIVE S ANALYSI S Criterio n

1 ) Protectio n o f Huma n Healt h and Environmen t 2 ) Attainmen t o f ARAR s 

### 3 ) Lon g ter m Effectivenes s 4 ) Reductio n o f Toxicity

, Mobilit y o r Volum e 5 ) Shor t ter m Effectivenes s 6 ) Implementabilit y 

### 7 ) Cos t 8 ) Stat e Acceptanc e 9 ) Communit y Acceptanc e Tota l Alternativ e 1 N o 

### Actio n
5 5 4
2 5 5 5 5 5 4 1 

### Alternativ e

2 Institutiona l Control s
5 5 4


### 2 4 5 4 

### 5 5 3 9 

### Alternativ e

3 Resourc e Utilizatio n
5 5 5
2 3 3 3 5 5 3 6 Notes : Scal e o f 1-5 , wher e 5 = Highes t Attainmen t 

### Source : Terranext

, 1996 a

P:\32SO-OU\WPJIOD\TABLE3.WP

DAPPENDI X A ARARsSUMMAR Y O F FEDERA L AN D STAT E ARAR S

Clea n Air Act

, Nationa l Primar y and Secondar y Ambien t Ai r Qualit y Standard s

Nationa l Histori c Preservatio n Act(NHPA ) Executiv e Orde r 1 1 59 3 Protectio n an d Enhancemen t o f th e Cultura l Environmen t

Hazardou s Material s Transportatio n Ac t 4 0

CF R Par t 5 0

16USC§470£issg

. 40CFR§6.301(b ) 3 6 CF R Par t 63 , Par t 65 , Par t 80 0 1 6 US C § 47 0

4 9 US C §1801-181 3 4 9 CF R 107 , 171-17 7 N

o

Y e s
Y e s

Y e s (fo r contingenc y reus e only ) N

o

— — Nationa l

ambien t ai r quality standard s (NAAQS ) ar e implemente d throug h th e Ne w Sourc e Revie w Progra m an d Stat e Implementatio n Plan s (SIPs)

. Th e federa l Ne w Source Revie w progra m addres s onl y majo r sources

. Ther e wil l b e n o emission s associated wit h th e chose n remedial actio n i n OU3

. Emission s associated wit h th e contingenc y remed y wil l b e limite d t o fugitiv e dust associate d wit h movin g an d sortin g th e sla g fo r reuse

. Thes e activities wil l
no t constitut e a majo r source

. Therefore

, attainmen t an d maintenanc e o f NAAQ S pursuant t o th e Ne w Sourc e Revie w Progra m ar e no t ARARs

. Se e Colorad o Ai r Pollutio n Preventio n an d Contro l Ac t concernin g applicabilit y o f requirement s implemente d throug h th e SIP

. Expand s histori c preservatio n programs ; require s preservatio n o f resource s include d i n o r eligibl e fo r listin g o n th e Nationa l Registe r fo r Histori c Places

. Direct s federa l agencie s t o institut e procedure s t o ensur e program s contribut e t o th e preservatio n an d enhancemen t
o f non
- federall y owne d histori c resources

. Consultatio n wit h the Advisory Counci l o n Histori c Preservatio n i s required i f remova l activitie s shoul d threate n cultura l
resources

. Regulate s transportatio n o f hazardou s materials

.

P:\3280-014\FINALROD\OU

3 ARAR.FN LSUMMAR Y O F FEDERA L AN D STAT E ARAR S (Continued )

STAT E O F COLORAD O Colorad o Ai r Pollutio n Preventio n an d Contro l Ac t 5 CC R 1001 , Regulatio n 1 , Sectio n III. D Y e s Require s al l source s o f paniculat e emission s t o appl y technicall y feasibl e an d economicall y reasonabl e contro l measures

. APC D ha s th e authorit y t o as k for a fugitiv e emissio n contro l pla n fro m an y location
, i f blowin g paniculat e matter i s a problem

. Th e sit e doe s no t nee d t o b e i n active use fo r thi s requiremen t t o apply

. Technicall y feasibl e an d economicall y reasonabl e contro l measure s wil l b e applie d t o reus e o f th e stockpile d fin e slag

. Colorad o Ai r Pollutio n Preventio n an d Contro l Ac t 5 CC R 1001-3 ; Section s III.D.l.b.c.d

. Section s III.D.2.b,c,e,f,g

. Regulatio n 1 Y e s (fo r contingenc y reus e only ) Regulatio n

No

. 1 provision s concernin g fugitiv e emission s fo r storag e an d stockpilin g activities , hau l roads
, an d hau l truck s ar e applicabl e ( 5 CC R 1001-3 ; Section s III.D.2.b,c,e,f,g. ) t o the reus e contingency

. Colorad o Ai r Pollutio n Preventio n an d Contro l Ac t 5 CC R 1001-4 ; Regulatio n 2 Y e s (fo r contingenc y reus e only ) Provision

s concernin g odor s woul d b e applicabl e i f contingenc y reus e wer e t o caus e objectionabl e odors

. Colorad o Ai r Pollutio n Preventio n an d Contro l Ac t 5

CC R 1001- 5 Regulatio n 3 APEN s Y e s (fo r contingenc y reus e only ) Substantiv e

provision s o f APEN s wil l b e met

. Colorad o Ai r Pollutio n Preventio n an d Contro l Ac t 5

CC R 1001-1 0 Par t C (I ) &(II ) Regulatio n 8 Y e s (fo r contingenc y reus e only ) Regulatio n

8 set s emissio n limit s fo r lead

. Applicant s ar e require d t o evaluat e whethe r the propose d activitie s woul d resul t i n th e Regulatio n 8 lead standar d bein g exceeded

. Ther e ar e n o emission s associated wit h th e chose n remedia l action

. Th e contingenc y reus e i n OU 3 i s no t projecte d t o excee d th e emissio n level s fo r lead
, althoug h som e lea d emission s ma y occur
. Complianc e wit h Regulatio n 8 wil l b e achieve d b y adherin g t o a fugitiv e emission s contro l pla n prepare d i n accordanc e wit h Regulatio n No

. 1

.

P:\3280-014\FINALROD\OU3ARAR.FN

LSUMMAR Y O F FEDERA L AN D STAT E ARAR S (Continued )

Colorad o Ai r Pollutio n Preventio n an d Contro l 5

CC R 1001-14 ; Ambien t Ai r Qualit y Standard s Y e s (fo r contingenc y reus e only ) Provision

s concernin g Stat e TS P standard s an d Federa l PM-1 0 standard s woul d appl y i f contingenc y reus e occurs , o r i f th e Sit e i s th e subjec t o f fugitiv e emissio n complaints

. I n suc h a case , complianc e wit h th e applicabl e provision s o f th e Colorad o ai r qualit y requirement s wil l b e achieved b y adherin g t o a fugitiv e emission s contro l pla n prepare d i n accordanc e wit h Regulatio n No

. 1

. Colorad o Wate r Qualit y Contro l Act

, Stor m Wate r Discharg e Regulation s 5

CC R 1002- 2 Y e s Establishe s requirement s fo r stor m wate r discharge s (excep t portion s relatin g t o Site-wid e Surfac e an d Groundwater)

. Substantiv e requirement s fo r stor m wate r discharge s associate d wit h constructio n activitie s ar e applicable

. Colorad o Nois e Abatemen t Ac t CRS§ §

25-12-10 1 t o 10 8 Y e s (fo r contingenc y reus e only ) Establishe s

maximu m permissibl e nois e level s fo r particula r tim e period s and lan d use.___

_

P:\3280-014\FINALROD\O.U3ARAR-FN

L