UNITE D

STATE S ENVIRONMENTA L

PROTECTIO N

AGENC Y REGIO N VIII 9 9 9 18t h STREE T

- SUIT E 50 0 DENVER

, COLORAD O 80202-246 6 8HWM-S R 

### 37077 6 Ref : ACTIO N MEMORANDU M DATE : SUBJECT:

FROM : T O : Octobe r

31
, 199 5 Reques t fo r Remova l (Response ) Actio n a t th e Californi a Gulc h Nationa l Prioritie s Lis t Site

, Leadville

, Colorado : ACTION

MEMORANDU

M fo r a Time-Critica l

Remova l Actio n fo r a Portio n o f Uppe r Californi a Gulch

, Operabl e Uni t 4 o f th e Site

. S a m Vance

, 8HWM-S R M a x H

. Dodso n Assistan t Regiona l Administrato r Offic e o f Ecosystem s Protectio n
and Remediatio n Fina l NP L Sit e I D # 2 9 CERCLI S I D # COD98071793 8 Category o f Removal : Tim e Critica l A

R Sit e Post-Decisio n T •'-'.
- . P- ^ FOI / Wor k •rerforme' 1 " Fil e Pla n t f 2,je > Keywor d fV,'- ; l ^

I

. Purpos e Thi s Actio n Memorandu m document s th e Agency' s selectio n o f a remova l (response ) actio n describe d herei n fo r Uppe r Californi a Gulc h (UCG)

, a n are a whic h ha s been contaminate d wit h tailing s fro m histori c minin g an d milling operations

. T h e purpos e o f th e propose d respons e actio n i s t o improv e th e temporar y syste m whic h i s used t o diver t th e flo w i n Uppe r Californi a Gulc h t o th e Ya k Tunne l Wate r Treatmen t Plant

. Thi s syste m wa s installe d pursuan t t o th e Secon d Amendmen t t o EP A Unilatera l Administrativ e

Orde r No

. CERCLA

- VIII-89-2 0 t o conduct a treatabilit y stud y o f O U 4 (UCG ) water

. Th e syste m i s designe d t o us e excess treatmen t plan t capacit y t o improv e th e qualit y o f th e discharg e int o Californi a Gulc h downstrea m o f th e Ya k Tunne l Wate r Treatmen t Plant

. T h e Remova l Actio n in UC G i s consisten t wit h th e remedia l activitie s t o b e undertake n b y EP A a t O U 4

. Fina l remedial alternative s fo r al l area s o f O U 4 wil l b e evaluate d i n the Feasibilit y Stud y (FS ) an d Recor d o f Decisio n (ROD ) fo r O U 4

. The RO D for O U 4 wil l ultimatel y determin e whethe r remedia l action s beyon d thos e respons e action s implemente d pursuan t t o thi s Actio n Memorandu m ar e required

. Th e

Printed on Recycled Paperprimar

y goa l o f thi s Remova l Actio n i s t o reduc e the ris k t o 

### th e aquatic an d terrestria l ecosystem s b y reducin g th e releas e o f contaminate d

materia l int o th e environment fro m UCG

. T h e Desig n Criteri a fo r th e diversio n improvement

ar e outline d below : 

### O Th e structur e wil l be temporary ; expecte d 

### operatin g lif e i s les s tha n 5 years

. O Desig n an d implementatio n

o f th e diversio n wil l b e consisten t wit h an y remediatio n a t O U 4

. O Diversio n

o f Uppe r Californi a Gulc h flow s t o th e 

### Treatmen t Plan t ca n be controlled

. O Sedimen t loa d fro m Uppe r Californi a Gulc h wil l b e 

### reduced

. O Th e diversio n embankmen t wil l b e stabilize d fo r hig h flo w conditions

. 

### O Th e existin g flum e a t CG-1

, jus t upstrea m o f th e diversio n sedimen t pond

, wil l remai n i n plac e allowin g continue d monitorin g o f UC G flows

. 

### Remova l alternative s

t o trea t o r otherwis e directl y remediat e surfac e wate r o r ground wate r i n O U 4 hav e no t 

### bee n evaluate d i n thi s Actio n Memorandum

. I I

. Californi a Gulc h

- Sit e Condition s an d Background T h e Californi a Gulc h Sit e wa s liste d o n th e Nationa l Prioritie s Lis t o n Septembe r 8
, 1983

. Th e Sit e i s in a 

### minin g are a coverin g 1 6 1/ 2 squar e mile s o f a watershe d tha t drain s alon g Californi a Gulc h t o th e Arkansa s River

. Startin g in 1859
, th e are a wa s mined extensivel y fo r gold

, 

### lead

, silver

, copper
, zinc
, an d manganese

. Californi a Gulc h collect s runof f that drain s numerou s abandone d mine s an d waste s fro m mining
, milling an d smelting

. Miner s buil t th e Ya k Tunne l t o drain wate r fro m th e min e working s an d t o mak e mineral exploratio n an d developmen t easier

. Thi s tunne l drains hundred s o f mile s o f min e workings in it s 4-mil e undergroun d cours e an d prio r t o installatio n

o f th e Ya k Tunne l Wate r Treatmen t Plant

, discharge d approximatel

y 21 0 

### tons o f variou s metal s eac h yea r int o Californi a Gulch

. Seventy-fiv e know n mill s dumpe d tailing s int o 5- 6 mile s o f drainages

. Si x impounde d tailing s dump s surround th e Cit y 

### o f Leadville

. Man y smelters

, whic h ar e locate d aroun d th e city
, processe d silver

, lea d an d zin c a t variou s times

.Heavy

meta l residue s ar e presen t i n muc h o f th e City

. Th e 

### Arkansa s River whic h receive s wate r fro m th e Californi a 

### Gulch

, ha s bee n classifie d a s a recreationa l resource , an d i s use d heavil y fo r irrigation
, livestoc k watering
, publi c wate r supplie s an d fisheries

. Approximatel

y 4,00 0 liv e in nearb y Leadvill e an d Lak e Count y (Se e Sit e Locatio n Ma p - Figur e 1)

. III

. Uppe r Californi a Gulc h (UCG ) A

. Backgroun d 

### A temporary diversio n was constructe d i n Californi a Gulc h jus t abov e th e Yak Tunne l Porta l in 199 3 

### pursuan t t o th e Secon d Amendmen t t o EPA' s UAO CERCL A N o

. VIII-89-20

. I t provide d fo r th e diversio n o f a 

### portio n o f UC G wate r t o th e Yak Tunne l Treatmen t Plan t t o conduc t a treatabilit y stud y o f th e Ya k Plan t t o determin e i f it s excess capacit y coul d be used t o trea t U C G flows

, includin g flow s fro m sprin g run-of f an d fro m periodi c stor m events

. Th e 199 3 stud y conclude d 

### tha t th e treatmen t plan t coul d successfull y trea t UC G wate r an d remai n i n complianc e wit h effluen t standard s se t fo r th e plant

. Asarc o continue d t o trea t UC G wate r durin g th e 199 4 an d 199 5 runof f seasons

. Hig h flow s durin g th e 199 5 season overtoppe d th e existin g diversio n structure
, an d diversio n o f UC G wate r t o th e 

### treatmen t plan t wa s halted

. Improvement

s t o th e existin g diversio n structur e ar e planne d t o continu e 

### treatin g UC G water
, a s th e treatmen t plan t capacit y allows

. 

### T h e Yak Tunne l Wate r Treatmen t Plan t wa s constructe d t o trea t discharg e fro m th e Yak Tunnel

. Th e maximu m capacit y o f th e treatmen t plan t i s approximatel

y 115 0 

### gallon s pe r minut e (gpm)

. Th e treatmen t plan t als o treat s surfac e runof f an d sprin g discharg e tha t occu r a t th e treatmen t plan t site

. Generally

, pea k flow s 

### emanatin g fro m th e Ya k Tunne l var y fro m 60 0 t o 110 0 gpm
, bu t average yearl y flow s ar e considerabl y les s tha n thes e pea k limits

. Combine d plan t sit e surfac e runof f an d sprin g discharg e fo r th e 199 3 seaso n wa s wel l belo w th e norma l Ya k Tunne l peak flows

, a t approximatel y 45 0 gp m durin g th e 199 3 season

. T h e shortfal l durin g averag e an d pea k flo w condition s 

### f o r 199 3 provide d th e treatmen t plan t wit h sufficien t
excess capacit y t o allo w fo r treatmen t o f a t leas t a portio n o f th e UC G water

. Typica l pea k flow s ar e i n 

### t h e range o f 90 0 t o 150 0 gpm

. Uppe r Californi a Gulc h i s generall y dry excep t durin g sprin g runoff

. Drawin g

### 1

depict s th e locatio n o f th e diversio n structur e in relatio n t o th e Ya k Tunne l Wate r Treatmen t Plan

, th e 

### Y ak Porta l an d othe r sit e features

. B

. Sit e Characterizatio n

- Uppe r Californi a Gulc h 

### Characterizatio n

o f th e wate r qualit y in Uppe r Californi a Gulc h (UCG ) wa s conducte d in Jun e o f 1994

. 

### Fiv e gra b sample s indicate d th e following : Aluminu m 11,20 0

t o 21,50 0 ug/ L 

### Arseni c 5

t o 2 5 ug/ L Cadmiu m 12 0

t o 24 0 ug/ L Coppe r 49 0

t o 1,14 0 ug/ L Lea d 24 7

t o 1,24 0 ug/ L Zin c 17,20 0

t o 46,00 0 ug/ L Durin g th e perio d Asarc o was divertin g an d treatin g UC G 

### flow s i n th e Yak Tunne l Wate r Treatmen t Plant

, th e effluen t fro m th e plan t wa s monitore d fo r complianc e wit h it s permit limitations

.

N o exceedence s o f th e permit limitation s occurred

. Fo r furthe r information

, 

### refe r t o th e "Uppe r Californi a Gulc h Treatabilit y Study

, Sprin g 1994
, (Jun e 1995). " C

. Othe r Action s t o Dat e 

### T h e respons e actio n propose d in thi s Actio n Memorandu m replace s an d augment s th e temporary diversio n structure s constructe d

i n 199 3 pursuan t t o EPA' s Secon d Amendment t o Administrativ e

Order CERCLA-VIII-89-2 0 date d Jun e 16
, 1993

. 

### D

. State an d Loca l Authorities Role s None

. I V

. Threat s t o Publi c Healt h o r Welfar e o r th e Environment I f th e diversio n structur e i s no t constructed

, th e sedimen t

a n d metal s loading s fro m Uppe r Californi a Gulc h (UCG ) t o 

### Lower Californi a Gulc h (O U 8 ) an d th e Arkansas Rive r wil l continue

.V

. Endangermen t

Determinatio n 

### Actua l and/o r threatene d release s o f hazardou s substance s fro m th e wate r in Uppe r Californi a Gulch

, i f no t addresse d b y implementin g th e remova l actio n selecte d i n this Actio n 

### Memorandum

, ma y presen t an endangermen t t o publi c health

, o r welfare

, o r th e environment

.

Th e releas e o f significan t quantitie s o f contaminate d

material s wil l continue

. V I

. Propose d Actions/Performanc e

Standards/Estimate d

Cost s A

. Propose d Action s 

### 1

. Embankment

Regradin g 2

. Spillwa y Constructio n 

### 3

. Sedimen t Pond Clean-ou t an d Enlargin g 4

. Outle t and Drai n Installatio n 5

. Upstrea m Sediment/Debri s

Contro l

6

. Operatio n and Maintenanc e 

### Thes e propose d action s ar e include d in th e attache d Work Pla n fo r Uppe r Californi a Gulc h Diversio n Improvements

, prepare d by Shepher d Mill

, Inc.

, Reference : SM I #01-253
, date d Octobe r 9
, 199 5 

### B

. Applicable o r Relevan t an d Appropriate Requirement

s (ARARs)

1. 0 Chemica l Specifi c ARARs - 1. 1 Clea n Wate r Ac t - Sectio n 40 2 - NPDES/CDPE S



### 1 . 2 Clea n Wate r Ac t - Surfac e Wate r Qualit y Criteri a (Stat e ARAR )

2 . 0 Actio n Specifi c ARARs - None

.

### 3 . 0

Locatio n Specifi c ARARs - 3. 1 Clea n Wate r Ac t - 

### Sectio n 40 4 - Dredg e an d Fil l C

. Performanc e

Standard s Th e ARARs ar e bein g me t through complianc e wit h 

### Performanc e Standards

. Th e Performanc e Standard s ar e include d i n the Statemen t o f Work an d ar e summarize d below : 

### 1

. Th e designe d an d constructe d respons e actio n shal l includ e provision s t o ensure tha t ther e ar e no visibl e emissions (dust ) durin g remova l activities

. 

### 2

. Th e desig n shal l contai n requirement

s t o ensur e tha t activitie s associate d wit h this actio n shal l

no t adversel y impac t th e operatio n o f th e Ya k Tunne l Wate r Treatmen t Plant

. 3

. A long-ter m maintenanc e

progra m ma y b e implemente d i f require d b y th e Fina l Recor d o f Decisio n fo r 

### Operabl e Unit 4 (O U 4 ) t o ensure th e long-ter m effectivenes s o f th e respons e action

. 

### 4

. Operatio n and maintenanc e task shal l b e performe d

a s indicate d i n the Work Plan

. D

. Projec t Schedul e 

### T h e respons e actio n is schedule d fo r completio n durin g t h e 199 5 fiel d season

. 

### E

. Estimate d Cost s 

### Thi s respons e actio n i s bein g performe d b y Resurrectio n Minin g Company

. 

### VII

. Expecte d Chang e i n th e Situatio n Shoul d Actio n B e Delaye d o r N o t Take n 

### Shoul d this remova l actio n b e delayed

, o r no t taken

, ther e wil l remai n potentia l ris k o f exposur e t o th e publi c t o heav y metal s containe d in th e sediment s in runof f fro m Uppe r 

### Californi a Gulc h an d continue d releas e o f contaminate d sediment s int o Californi a Gulc h an d th e Arkansas River

.

### VIII

.

Outstandin g Polic y Issue s A Recor d o f Decisio n wil l be issue d selectin g th e fina l remedia l actio n fo r Operabl e Unit 4 (OU 4 ) o f this Sit e afte r th e respons e actio n selecte d i n thi s Actio n Memorandu m i s completed

. I X

. Enforcemen t 

### Pursuan t t o th e 199 4 Consen t Decree

, Resurrectio n

Minin g Compan y ha s agree d t o implemen t respons e action s fo r th e O U 4 portio n o f th e Site

. X

. Recommendatio n 

### Thi s decisio n document represent s th e selecte d remova l actio n fo r th e Uppe r Californi a Gulc h portio n o f O U 4 o f th e Californi a Gulc h Superfun d Site

, i n th e Cit y o f Leadville

, 

### Count y o f Lake

, Stat e o f Colorado

. I t wa s develope d i n accordanc e wit h CERCLA

, a s amended

, and i s no t inconsisten t wit h th e NCP

. Thi s decisio n i s base d o n th e Administrativ e Recor d fo r th e Site

. Condition s a t Uppe r Californi a Gulc h mee t th e NC P Sectio n 

### 300.415(b)(2 ) criteri a fo r a remova l an d I recommend approva l o f th e propose d remova l action

. APPROVA L



### M a x H

. Dodso n Assistan t Regiona l Administrato r 

### Offic e o f Ecosystem s Protectio n and Remediatio n DISAPPROVA L



### M a x H

. Dodso n Assistan t Regiona l Administrato r 

### Offic e o f Ecosystem s Protectio n and Remediatio n

## C

O L\O R A D O

NOT TO SCALE 

### CALIFORNIA GULCH 

### SUPERFUNb SITE



# *•• l'H)jrt:t 664-OWO RESWLOC.DWG J.RAY

t)ntnm By: K.CONRATH RESURRECTIO N

MININ G COMPAN Y O N E UMtre O BAN K CENTE R 170 0 LINCOL N STREE T DENVER

. COLORAD O •«<> ) Sralr H/A

Dtltr JUNE 1995 

### FIGURE 1 

### CALIFORNIA

GULCH SITE 

## GENERAL LOCATION

## SHEPHER D

MILLE R
HCCRPORATe D 

## SHEPHER D MILLE R
:NCCRPOFIATH

D



### • / A / /