environmental Protection
           Agency
              Office of
              Emergency and
              Remedial Response
EPA/HOD/R09-86/011
October 1986 •
SEPA
Superfund
Record of Decision
            Iron Mountain Mine, CA

-------
           TECHNICAL REPORT DATA              
       {Pftast 'tad I"SlfUCl/O'U 0" (ht ,tVt"t IHf(Nt r:o,""lt,i"l)           
,. AEPOAT NO.       12.        J. RECIPIENT'S ACCeSSION NO.   
EPA/ROD/R09-86/0ll                        
TITLE ANO SUITITLI              5. REPOAT OATE       
SUPERFUND RECORD OF DECISION                -  1 1 Q~ 1\  
Iron Mountain,  CA             e. ,eAPORMINCi OROANIZATION COOE  
7. AuTHOACSI                8. peAFORMINCi ORCiANIZATION REPORT NO.
e. peAFORMINCi OACiANIZATION NAMe ANO AOORESS       10. PAOCiRAM EL.EMENT NO.   
                  ". CONTI'IIAI;T/I;OI'IIANT NO.     
12. SPONSOAINCi ACieNCY NAME ANO AOORESS        13. Type OF RepOAT ANO peRIOO CO\lEI'IEO
U.S. Environmental Protection Agency             !:'; "",1 .:1/"\1"\ .:I",...,.....+-  
401 M Street, S.W.             14. SPONSORINCi ACieNCY cooe   
   .~.                     
Washington,  D.C.  20460                 800/00      
15. SUPPl..eMENTAAV NOTES                          
16. ABSTRACT                             
Iron Mountain Mine (IMM) is located in fhesoutheastern foothills of the Klamat.h  
Mountains, approximately nine miles northwest of the City of Redding, California.   
        -  
Between the 1860s and 1962, IMM was periodically mined for iron, silver, gold, coppe r , 
. zinc, and pyrite. The mine area, believed to be one orebody which has been segmented by
faulting, is located on 4,400 acres of property that includes underground workings, an 
open pit mining area, waste rock dumps,  and tailings piles. Rainfall, infiltrating inte
the underground mine workings, mixes with ground water and the ore zone to produce  
sulfuric acid and high concentrations of zinc, cadmium, and copper.  The resulting heavj
metal-laden acidic waters, referred to as acid mine drainage (AMD), eventually dischargE
through mineadits or ground water seepage into the Spring Creek watershed streams,  
Spring Creek Reservoir, and the Sacramento River. The primary contaminants of concern 
incl ude:  AMD,  copper, cadmium, and zinc.                  
The desired  remedial action for this  site was not selected due to excessive cost. 
Instead, a fund balancing waiver to the NCP was invoked, and an alternative that most 
closely approaches ARARs was selected.  The alternative includes: capping selected  
cracked and  carved ground areas using a  soil~cement mixture or other suitable material;
diverting clean surface water in Upper Spring Creek to Flat Creek, diverting clean  
surface water in South Fork Spring Creek to Rock Creek, and diverting clean Upper   
(See Attached Sheet)                         
'7.          Kev WOROS ANO OOCUMENT ANAL.VSIS           
a.     oaSCRIPTORS      b.loeNTIFIERS/OPEN ENOEO TERMS C. COSA TI Field/Group 
Record of Decision                          
Iron Mountain,  CA                          
Contaminated Media: .sw, sediments                     
Key contaminants: acids, inorganics,                    
heavy metals,  cadmium                         
8. OISTRIBuTION STATEMENT        19. SECU RI TY CLASS I TIlls Rtpon/  21. NO. OF ;>Aces  
                  None         204 
              20. SECUFlITY CLASS I This POIlt!  22. ;>"'ICE   
                  ,,-~~           
!PA 11- 2220-1 (R.... A-77)
IO",CV'OUS EO' TIOH IS OeIOL.ETC

-------
EPA/ROD/R09-86/0ll
I-ron MOW1tain, CA
16.
ABSTRACT (continued)
Slickrock Creek water aroW1d waste rock and tailings piles; enlarging Spring
Creek Debris Dam from its present capacity of 5,800 acre feet to 9,000 acre
feet; implementing perimeter control as needed to minimize direct contact
threat; and performing hydrogeologic ~tudy and field-scale pilot
demonstration to better define the feasibility of utilizing low-density
cellular concrete to eliminate 'or reduce acid mine drainage formation. The
estimated capital costs for the fW1d-balanced alternative is $68,100,000
with O&M present worth costs of $4,100,000.
--.

-------
RECORD OF DECISION
IRON MOUNTAIN MINE
REDDING, CALIFORNIA
DOCUMENTS REVIEWED:
. .
~
:c '".
,

I am basing my decision primarilyori the following documents
describing the cost-effectiveness of remedial alternatives for
the Iron Mountain Kine sita:
o
Final Remedial Investigation Report, Iron Mountain Mine,
near Redding, California, CH2M Hill, August 1985.
o
Public Comment Feasibility Study, Iron Mountain Mine, Redding,
California, CH2M Hill, August 2, 1985.
o
Public Comment Feasibility Study Addendum, Iron Mountain
Mine, Redding,~alifornia, dated July 25, 1986.

Responsiveness Summary, dated September 1986.
o
o
Summary of Remedial Alternative Selection, September 19, 1986.
DESCRIPTION OF OPERABLE UNIT:
o
Cap selected cracked and caved ground areas on Iron Mountain
above the Richmond ore body using a soil-cement mixture or
other suitable material *;
o
Divert clean surface water in Upper Spring Creek to Flat
Creek, divert clean surface water in South Fork Spring
Creek to Rock Creek, and divert clean Upper Slickrock Creek
water around waste rock and tailings piles;
o
Enlarge Spring Creek Debris Dam (SCDD) from its pr~sent
capacity of 5,800 acre feet to 9,000 acre feet;
o
Implement perimeter control as needed to minimize direct
contact threat; and
o
Perform hydrogeologic study and field-scale pilot demonstration
to better define t~e feasibility of utilizing low-density
cellular concrete to eliminate or reduce acid mine drainage
formation.
* [Based on the present record, I believe that construction
of a partial cap over the Richmond ore body is a necessary source
control component of the overall remedy as envisioned by EPA.
However, the potentially responsible parties are proposing to

-------
implement a solution mining operation that may be able to
effectively exploit the ore body as a resource and control the
. discharge of acid mine drainage from the mountain. Construction
of the partial cap could adversely affect the solution mining
operation. EPA intends to further explore the implementation
and environmental results associated with a solution Mining
operation during the next 60 days. Therefore, no action will be
taken to .implement the capping comp?ne~t for a peri09 of at
least 60 days from the signature date on. this Record 'of Decision.
To the extent that new information ca~sei EPA to modify its
present opinion that the mountain should be partially capped,
EPA would provide to the public an opportunity to comment prior
to making any final decision. I will make a decision regarding
the implementation of the capping componen~ after the 60-day .
period has ended.]
DECLARATIONS:
Consistent with~-the Comprehensive Environmental Response,
Compensation, and Liability Act of 1980 (CERCLA) and the National
Oil and Hazardous Substances Pollution Contingency Plan (NCP)
40 CFR Part 300 et.seq., I have determined that the operable
unit remedy previously identified is a component of what will be
the appropriate Fund-financed action for this site in accordance
with section 300.68 (j) of the NCP. These are components of a
final EPA remedy that will provide adequate protection of the
public. heal th and welfare and the environment.
I

I

I'
I
I
I
The selected operable unit, and ultimately the final remedy,
will not meet. all the requir~ments of the Clean Water Act (CWA)
33 U.S.C. S125l et.seq. and, therefore, is somewhat less protec-
tive than the remedial action alternative that complies with all
federal and state regulat~ons. The reason is that federal water
quality standards will be met in the Sacramento River below
Keswick Dam but not in the immediate receiving waters as required
by the CWA. Also, if treatment is required, not all point source
discharges will receive Best Available Technology and not all
- non-point sources will be addressed through Best Management
Practices. However, the final remedy is expected to be substan-
tially effective in minimizing the discharge of heavy metals from
the site which would threaten public health and welfare or the
environment. I have determined that the level of protection
provided by the operable unit most effectively mitigates and
minimizes- threats to and provides adequate protection of public
health and welfare and the environment considering the need for
additional protection at this site and the amount of money that
may be available in the Hazardous Substance Trust Fund to respond
to other sites which present or may present a threat to public
health and welfare and the environment. I have also determined

-------
. 1"
that the selected remedy is that remedy which most closely
apQroaches the level of protection provided by applicable or
relevant and appropriate Federal requireMents considering the
specific fund-balanced sum of money available for the Iron
Mountain Mine site.
The State of California has heen consulted and agrees with
the approved operable unit and EPA!s. strategy leadjng to the
implementation of a final remedy. !
-------
SUMMARY OF REMEDIAL ALTERNATIVE SELECTION
Iron Mountain Mine
Redding, Caiif~rp~a
.'
. .'
.. ..
-
.-'
September 19, 1986
Prepared by Thomas A. Mix
Federal Response Section
Toxics and Waste Management Division
United States Environmental Protection Agency
215 Fremont Street
San Francisco, California 94105

-------
III.
VI.
VII.
VIII.
IX.
XI.
XII.
XIII.
XIV.
XV.
XVI.
XVII.
TABLE OF CONTENTS
I.
Site Location and Description
. . . . . . . . . . . . . . . . . . . . .
II.
Overview of the Problem ...........................
"
Site History
I , . . '. .
. . . . . . . . . . . . . . . .,. .~ - . . . . . . . . . . . . . . . . . ~ .
A.
B.
Mining Hist9ry ................................
Previous "Remedial Actions .....................
IV.
EPA Involvement
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
A.
Remedial Investigation ........................
V.
Enforcement Analysis
. . . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Alternativ~~'Evaluation ..~........................
A.
B.
c.

" D.
E.
Introduction...... . .. . . . ... a'. . ... .. ..... ... ... 27

Site-Specific Action Levels ................... 29

Technology Development........................ 29
Components for Detailed Analysis ..............30
Description of Combined Remedial Action

~lternatives .................................41
Alternative Screening ......................... 44
F.
The Iron Mountain Mine Remedy.....................
Fu n d - B a 1 a n c i n g ...................................
Summary Eval~ation of Alternative~
. . . . . . . . . . . . . . . .
A.
Features and costs of combined remedial
actl\11tes
B.
Evaluation of combined remedial alternatives
X.
Identification of Fund- Balanced Remedy and
Remedy Selection Strategy.........................
Summary of Racommended Operable Unit
. . . . . . , . . . . .. . .
Recommended Cleanup Objectives and

. De s i g n Yea t" ........................
...~...........
Consistency with Othec En\1iron~ental Laws
.........
Operation and Maintenance
............ f............
Co~munity Relations
. . .' . . . . . . . . . . . . . . . . . . . . . . . . . . . .
Schedule
..............
..... .......................
Future Action
.. ..... ......... .... .................
1
3
4
4
6
8
8
27
27
49
50
52
53'
54
56
58
59
59
63
63
66
67

-------
Figure 1.
Figure 2.
Table 1.
Table 2.
Table 3.
Table 4.
Table '5.
Table 6.
Table 7.
Table 8.
Table 9.
Table 10.
Table 11.
Table 12.
T"ible 13.
LIST OF FIGURES
Iron Mountain Mine Locatio~ Map .......:.~.......

,I . . .
2
. ,
Slickrock Creek Intensive Sampling
Site Location Map ~.............................
9
LIST OF TABLES
Relative Contribution of Metals from Sources..... 11
Average Chemical Composition of Discharges

from 5 Major Sources ........................... 12
80ulder C-reek Water Quality..................... 14
Percent Contribution of Boulder Creek Seeps and/
Tailings Piles/Waste Rock Dumps ................ 16
SLickrock Creek Water Quality................... 17
Spring Creek Water Quality...................... 20
Summary of Sacramento River Monitoring.......... '21
Summary of Flshkills Near Redding, California ... 23
Available Technologies .......................... 31
Components Retained for Detailed Analysis ....... 32
Technical Environmental and Institutional
Considerations for Remedial Action Components .. 33
Combined Alternatives Matrix
. . . . . . . . . . . . . . . . . . .. 46
Anticipated Water Quality Improvements with
CA-9' ........................................... 57

-------
SUMMARY OF
REMEDIAL ALTERNATIVE SELECTION
0'
0'
SITE: Iron Mountain Mine
REGION: IX
.
I .
SITE-LOCATION AND DESCRIPTION
Iron Mountain Mine is located in the ..southeastern foothills
of the Klamath Mountains, approximately nine miles northwest of.
the City of Redding, California (See Figure 1). Between the
1860's and 1962, Iron Mountain Mine was periodically mined for
iron, silver, gold, copper, zinc, and pyrite. The mine area is
located on 4,400 ac;..es of property that includes underground
workings, an open pit mining area, waste rock dumps, and tailings
piles. The rugged topography of the area is typical of a
mountainous region wit~ steep slopes bissected by streams.
Elevations range from 600 feet on the Sacramento River several
miles east of the mine, to 3,800 feet on top of Iron Mountain.
The climate of the Iron Mountain area is characterized by warm,
dry summers and cool, rainy winters.
Iron Mountain.averages 70- 80 inches of
year, most of it falling in the for~ of rain
of November and April. Snow accumulation of
common above the 2,000 foot elevation during
storms, but usually melts in a few days.
precipitation per -
between the months
several inches is
the November- March
Iron Mountain is drained by Boulder Creek to the north, and
Slickrock Creek to the south of the mine. Boulder Creek, a
perennial stream, receives a portion of its flows fro~ the Lawson
and Richmond adits via their mine portals. Slickrock Creek, an
intermittent stream, receives discharges from underground
seepage associated with Old Mine and/or No. a Mine and flows
from storm water drainage fro~ the Brick Flat Pit area. A debris
slide diverted the original Slickrock Creek drainage and ~uried
adits from which acid mine drainage is emanating. Two copper
gementation plants are located on site and function to remove
copper from controlled flows, such as those cololacted from mine
portals and conveyed to the plants oy a system of flumes.
Uncontrolled flows such as surface runoff containing acid and
heavy metals are discharged directly to receiving waters without
treatment.
Slickrock and Boulder Creeks flow southeastward into Spring
Creek. The Spring Creek De~ris Dam and Reservoir were built in
1963 as part of the Central Valley Project (CVP). Since 1963,
the waste has been collected in Spring Creek Reservoir and sub-
sequently metered into Keswick Reservoir. The flow releases of
the waste from the SDring Creek Reservoir is determined by the

-------
. . . .
.~. '.
..
I(U/fIIIQ(
~#tR
.
, .
:t.


...~tDDI~

m ...
-
.....
FICURE 1
- 2 -
I
1-

-------
- 3 -
amount of "dilution" water being released by the u.s. Bureau of
Reclamation from Shasta Lake. A principle objective in operating
the reservoir is to control the discharge of the conta~inated
. water such that. releases upstreamfro~ Shasta Lake.~rovide
sufficient dilution to meet current ~stablished le~~ts for copper,
zinc, and cadmium in the Sac~amento River. Spring Creek drains
into Kaswick Reseryoir which was formed by the construction of
the Keswick Dam on "the Sacramento River. Flat Creek, which also
drains a portion of the mining complex, enters Keswick Reservoir
just upstre~~ of Spring Creek. The Sacram~nto River is a valuable
fisheries resource and is used as a source of drinking water by
the City of Redding (population: approximately 50,000 people).
II.
OVERVIEW OF THE PROBLEM
Mineralized ZOAeS that have extensive underground workings
from past mining activities are the primary source of contamina-
tion. As rain falls on the ground above the mineralized zones,
it infiltrates into the underground mine workings where it mixes
with groundwater, .and then passes through the ore zone. As the
groundwater passes through the ore, sulfuric acid is produced,
and high concentrations of copper, zinc, and cadmium are leached
from the mineralized zone. The resulting heavy metals- laden -
acidic waters are ~eferred to as acid mine drainage (AMD).
The AMD is eventually discharged through mine adits (access
tunnels entering the orebody and used during underground mining
activities) or groundwater seepage into streams in the Spring
Creek watershed (Slickrock Creek and Boulder Creek). The AMD
mixes with runoff from the Spring Creek watershed and flows into
Spring Creek Reservoir. This reservoir serves to control discharges
from the Spring Creek watershed into the Sacramento River.

During periods of heavy winter rain, high volumes of runoff
are produced from the Spring Creek watershed. This also coincides
with high production of AMD from Iron Mountain Mine. At these
times, releases from Shasta Lake are frequently reduced to maximize
storage behind Shasta Dam and to prevent downstream flooding of
the Sacramento River. When high runoff causes the Spring Creek
Reservoir to exceed capacity, uncontrolled spills have occurred.
Under these conditions, the releases from Shasta Lake are at times
not sufficient to provide adequata dilution of the uncontroliad
discharge from the reservoir. As a result, levels of copper,
zinc, and cad~ium exceeding lethal concentrations for aquatic
lif~ periodically occur in the Sacramento River. The last major
adult fish kill occurred in 1969 when an estimated 200,000 salmon
were killed. More often, sublethal concentrations occur that
have detrimental effects on some aquatic species, including
reduced rates of growth, interference with physiological processes
necessary for successful ~igration, and inhibition of gill function.
Past investigations in the Iron Mountain Mine area have documented
the following environmental conditions which now exist and will
continue as a result of toxic drainage from Iron Mountain Mine:

-------
4.
5.
- 4 -
1.
Heavy metal contamination of Boulder Creek, Slickrock
Creek, Flat Creek, and portions of Spring Creek, causing
the elimination of aquatic life and all other beneficial
uses of these watercourses downstream of Iron Mountain
Mine. .
2.
Heavy metal contamination of Keswick Reservoir, causing
periodic fish kills ad a significant reduction in fish
and aquatic invertebrates and u~sightly deposits of
metallic sludges in the lower one and one-half miles
of the Reservoir downstream of Spring Creek. This con-
tamination has reduced, if not eliminated, recreational
uses of the lower Reservoir. "
. .......
3.
Periodic fish kills in KeswickReservoir and in the
Sacramento River downstream of Keswick Dam caused by
uncontrolled spills of contaminated water from Spring
Creek Reservoir. In addition, there are repeated
instances when the LC50 levels for juvenile salmon and
steelhead in the Sacramento River below Keswick Dam are
exceeded. These instances are caused by uncontrolled ""
spills at-Spring Creek Reservoir. In addition, short--
term exposure (6-8 hours) to high concentrations of
heavy metals occurs below Keswick Dam from normal water
releases at Spring Creek Reservoir during the Spring
Creek powerhouse start-up.
Accumulation of copper and cadmium in the tissue of .
resident fish below Keswick Dam at levels which greatly
exceed ~he statewide norm and which suggest adverse
reproductive and other physiological impacts. In
the case of cadmium, the levels in fish tissue below
Keswick Dam are over five times the statewide norm.
Temporary discontinuation of domestic water from the
Sacramento River for precautionary reasons during
uncontrolled spill events at Spring Creek Reservoir.
6.
Occasional loss of large volumes of fresh water in
storage when the U.S. Bureau of Reclamation has had.
". to release water from Shasta Dam to dilute high concen-
trations of heavy metals spilling from Spring Creek
Reservoir. "
III. SITE HISTORY
A.
Mining History
Iron Mountain Mine is the southernmost mine in the West
Shasta Mining District, an area mined since the early 1860's for
silver, gold, copper, z(nc, and pyrite. Although various parts

-------
- 5 -
'. . .
of Iron Mountain Mine were developed as separate mines, it is
generally believed that the ~assive sulfide deposits are part of
one orebody which has been segmented by faulting. .
. . . .
. .
. .
.Iron Mountain Mine .was first secur~d for poss"i:ble future
value as a source of iron ore ,in 1865. Silver ore was discovered
in 1879, and limited development and mining or Iron Mountain
Mine'sgossan (oxid~ o~es) caps began. A small milling and
leaching facility was constructed in the mid-1980's to process
the gossan material for silver recovery. ..In 1895, the Iron
Mountain Mine property was sold to British-owned Mountain Mining
Company, Ltd., following discovery of massive copper sulfide
deposits. Mining of the ore continued under the new ownership
until 1897, when the property was transferred to Mountain Copper
Company, Ltd., of London, England.
.-.
. The Old Mine orebody was the first massive sulfide ore to
be mined for commercial recovery of copper at IMM. Construction
of a smelter and a narrow-gauge railway to transport the ore
from thd mine to the smelter was completed in 1896.

Between 1902 and 1908, several lawsuits were brought against
Mountain Copper Company. Private property owners and the U.S. ""
Forest Reserve sued Mountain Copper for destruction of vegetation
by operation of the Keswick smelter, and an injunction was obtained
prohibiting the roasting of ore. Smelting was gradually transfer-
red to Richmond, California, and in 1907 the Keswick smelter was
completely shut dQwn. Mountain Copper completed a new smelter
and processing plant in Martinez, California in 1908.
The N~~ber 8 orebody, underlying the Old Mine orebody, was
discovered in 1907. The Number 3 Mine was developed concurrently
with the Hornet pyrite mine on the northeast side of the mountain.
Beginning in 1900, pyrite ore fro~ thd Old Mine, and later the
Hornet Mine, was sold for the production of sulfuric acid.
Process residues were returned to Mountain Copper Company's
Keswick Smelter for recovery of the copper, gold, and silver.
The procedure was greatly simplified with completion of Mountain
Copper's Martinez plant in 1908. The Martinez plant was complete
with copper smelter, an acid plant, and faciliti~s for ~anufactur-
ing co~~ercial fertilizers.
In"1914-l5, California's first copper flotation ~ill
was co~pleted at Minnesota, on the Iron Mountain railway.' The
mill operated until March 1919, when it was closed because of
,low cQPper prices. A nearly flat area, later referred to as
Minnesota Flats, was used for tailings disposal during the
operation of the mill. Pyrite ore tailings were also deposited
at Minnesota Flats during later periods of mining.
In 1920, a new crushing and screening plant was put into
operation near the Hornet Mine to replace the crushing opera-
tions at Keswick. It was operated until 1943. An aerial tram~ay

-------
- 6 -
was completed in 1921 to transport the ora to Matheson, a few
miles north of Keswick on the Southern Pacific Railroad line.
In 1928, as the copper marke~ improved, the ~innesota mill
was reconstructed just below the Numbe~.8 Mine portal. However,
tailings disposal in the steep' canyon was a major problem: a
tailings dam built on Slickrock Creek received numerous complaints
from the Californta ~ish and Game Commission. The dam was
destroyed by floods in 1933, and the operation was shut down due
to declining copper prices. A 250-ton/day cyanide leach plant
was constructed in 1929 to recover silver and gold from the
qossan in the area of the Old Mine orebody. The gossan was
23ned by open-pit methods, with tailings storage in Hogtown
Gulch, adjacent to Slickrock Creek. An estimated. 2.6 million
tons of gossan was .~ined from 1929 to 1942. The tailings initially
stored in Hogtown Gulch, were reported to have an iron content
of 50 to 55 percent: during later periods, the content was reported
to be as low as 30 to 35 percent.
Mining of the copper-zinc ore in the Ridhmond and Mattie
orebodies was begun in 1942. High wartime metals prices prompted
construction of a copper-zinc flotation plant at the Richmond
portal. The plant. operated from 1943 to 1947. Underground
mining of the Ric~mond orebody ended in 1956.

In 1955, a large landslide composed of mine mill tailings
filled the Slickrock Creek canyon to a reported depth of about
80 feet, covering two mine portals (Number a and Old Mine).
The Brick Flat orebody was mined by open-pit methods between
1955 and 1962. The first pyrite was mined in 1956 after the
removal of 2.5 million tons of overburden. All mining operations
were discontinued in 1963.
The Iron Mountain property was purchased from Mountain
Copper Company by Stauffer Chemical Company in 1967. The property
was subsequently sold to Iron Mountain Mines, Inc., in 1976.
There has been some core sampling, but there is no evidence that
mining has occurred under the current ownership.
B.
Previous Remedial Actions
Several actions have been taken that have had an effect on
the incidence and sev~rity of AMD problems at Iron Mountain Mine.
These measures, although lessening the pollution problems somewhat,
have not been successful in eliminating the conditions discussed
on page 4 of this document.
1.
Copper Cementation Plants
In 1940, Mountain Copper Company, Ltd., constructed a copper
cementation plant to recover copper from mine drainage in the
Boulder Creek drainage area. In the cementation process, scra9

-------
- 7 -
iron is contacted with the AMD resulting in the precipitation of
copper and dissolution of the scrap iron.

The Boulder plant and a simil,ar plant in the ~.lickrock
drainage, which was constructed by rrOI\,Mountainr(j,n:es, Inc., in
1977, have been oDerated int~rmittently to recover copper from
the AMD, thereby reducinlJ concentrations of copper in Spring
Creek and ~he Sac~amento River. The copper cementation plants
'remove approximately 300 pounds per day (annual average) of
copper from the /\MD when properly opera tec;1. Zinc and cadmi '.lffi,
and other elements are not removed by this treatmdnt method.
2.
Spring Creek Debris Dam
The SCDD was constructed in part to help prevent toxic
concentrations of metals and consequent fishkills as a result of
discharges of AMD to Keswick Reservoir. The objective is to
release ~~D from SCDD at a rate which will result in safe metal
concentrations below Keswick Dam. The debris dam has not been
entirely effective in achieving this objective, particularly
during,periods of high precipitation which can produce runoff
that exceeds storage capacity of SCDD. This results in un-
controlled spills of AMD. When Sacramento River base-flow is
being stored at th~ same time to conserve water in Shasta Lake -
or,to minimize downstream flooding, these acid ~etal-laden flows
from SCDD are not diluted sufficiently to prevent fishkills,
especially in the early life stages of fish.
In 1980, a Memorandum of Understanding (MOU) was developed
between the State Water Resources Control Board (SWRCB), U.S.
Bureau of Reclamation (USBR), and the California Department of
Fish and Game (CDFG) for the purpose of ~inimizing the Spring
Cre~k toxicity problem.
As part of this MOU, the USBR agreed to operate the Spring
Creek Debris Dam and Shasta Dam water management system in
such a manner that, to the extent possible, sufficient dilution
water would be available to ensure that State water quality
criteria below Keswick Dam would be ~et.
Also, under the agree~ent' the CDFG was to conduct fish
toxicity tests to provide a basis for permanent toxicity criteria,
release'schedules, and water quality objective. After two'
years of intensive laboratory and field work, the CDFG identified
the following levels of metals below which.protect all life
stages of anadromous salmon and steelhead below Keswick Dam:
copper (5.6 ug/l)i zinc (16.0 ug/l)i and caqmium (0.22 ug/l).
These recommended levels were adopted by the Regional Water
Quality Control Board as Basin Plan objectives for the Keswick
Dam area and approved by the State Water Resources Control Board
(SWRCB) in August 1984. These objectives were approved by EPA
on August 7, 1985 under Section 303 of the Clean Water Act.

-------
- 8 -
The Regional Board, acting on behalf of the SWRCB, was
responsible for undertaking environmental studies designed to
identify the most feasible means of mitigating the problem through
, source control. The MOU may ber~vised once remeq~al action is
completed at I ron Moun taln Mine. '..., . . ,. '. '..
IV.
EPA INVOLVEMENT
In June 1381, the State of California submitted the Iron
Mountain Mine site as a candidate foi the..Interim priorities
List (IPL). When the IPL was released in October 1981, Iron
Mountain Mine appeared in the fourth decade of candidate sites.
Later, on August 31, 1982, the state submitted Iron Mountain
Mine as a candidate for the National Priorities List (NPL). On
December 30, 1982, EPA proposed the Iron Mountain Mine site for
inclusion on the NPL. On September 8, 1983, through final rule-
making, the site was included on the NPL.
In September 1983, EPA commenced a Remedial Investigation
and Feasibility Study (RI/FS). The purposa of the RI was to
assess, the major sources of contamination leaving the site and
collect data needed to identify and evaluate potential remedies.
During the FS, the potential remedies were evaluated according ..
to technical, environ~ental, pUblic health, institutional, and -
cost criteria.
A.
Remedial Investigation (RI)
A comprehensive investigation for the Iron Mountain Mine
site was conducted between September 1983 and April 1985 to
determine the nature, cause and extent of the environmental
and potential public health impacts from past and continuing
discharges of AMD. The extent of the surface and ground water
.contamination was established through:
o Weekly sampling of the five major sources at the ~ine and
three locations on Spring Creek, andbi-weekly sampling at
4 locations along, the Sacramento River for heavy metals.
o Installation of flow measure~ent stations at a locations,
including mine 90rtals and downstream receiving waters.
o Measurement of precipitation at six gauges throughout the
area.
o Two comprehensive surface water sampling surveys, involv-
ing 76 sa~pling points were conducted in September 1983
and December 1983 to identify and quantify all AMD sources.
(See Figure 2)
o A review of existing information on tha site including
water quality, geology, and hydrology.

-------
.::~:~:~~~
LE.Ge.J.JO

7A/LIJ.lG.s
.srllEAM SAMPLE

tA.MO 5AMP~
°


\ 14
'v
~., :
11 '0'
~..- ') , ...'S '-..~
PORK Sft:JG 0,,-,-, .I\- d.9i
~IlIJJq Clt~~" '. ~/
O~Il.J.s OAM B'
8
e
INTENSIVi SAMPLING SITE.
LOCATION MAP
- 9 -

-------
- 10 -
Q A program of field mapping of the areas overlying the
Richmond orebody. This included geologic mapping, measure-
ment of fracture orientations, and delineation of subsidence
pits and t_heir tributary drai'n~ge .~reas. ..~. .

Q A program of drilling and monitoring for the Richmond
groundwater inv~stigation. This program included install-
ing f~ur monitoring wells adjacent to the Richmond orebody,
monitoring groundwater elevations, conducting aquifer
testing, and groundwater quality testing.
During the 17 month RI, approximately 450 surface and ground
water samples were collected and analyzed. A draft RI report
was released in December 1984: the RI report was finalized
and issued on Augu~t -23, 1985. The major findings of the RI
",-.
are discussed below.
1 .
Major Sources of Pollution
EPA's RI found that the following five major sources
account for approximately 72 percent of the copper and 86
percent of both zinc and cadmium being discharged from the
site during the sampling period.
Richmond Portal: This source is a mine adit into the
Richmond orebody which represents the major single source
of AMD at Iron Mountain Mine. The Richmond orebody has
been extensively mined, resulting in subsidence pits and
closed drainages on the surface overlying the zone. Water
which drains from the Richmond portal results from infiltra-
tion of surface water captured in the closed drainage areas
overlying the orebody and by lateral inflow of groundwater
from areas upgradient of the mine.
Lawson Portal: This source "is a mine shaft located on
Boulder Creek immediately below and to the east of the
Richmond portal. .'
Old No.8 Mine Seep: This source is located on the upper
end of Slickrock Creek and is believed to originate from
either the No.8 Mine and/or the Old Mine. The entryways
for these mines were covered by a slide in the 1950's.
Big Seep (below Okosh Mine): This source is made up of
seeps which discharge from the waste rock dump on the
south side of Slickrock Creek.
Brick Flat Pit By-Pass: Water that is discharged from this
source originates from the drainage area into Brick Flat Pit
and is carried outside the pit by an earthen dam.
The relative contribution of metals from these sources is
listed in Table 1: the average chemical composition of discharges
from these sources is shown on Table 2.

-------
-11-
Table 1. Relative Contribution of Metals
Averaged over 4 month sam~ling Program
:11 .'
.
   Average ' of All Average % of All Average % of All Cu,Zn & Cd
SOURCE  Ibs/dav Sources Ibs/day Sources ibs/day Sources Lbs/Day
Richmond             
Portal  180  31.0 1,118  70.0 7.8  69.0 5,600 
Lawson             
Portal  32  6.0 209  11.0 1.4  11.0 1,100 
     . .........         
Old No. 8            
Mine Seep 109  25.0 45  3.0 0.4  .4.0 1,000 
Big Seep  50  9.0 21  1.0 0.2  1.0 400 
Brick Flat            
Pit By-  52  2.0 73  1.0 0.6  1.0 L-o 0 0 
Pass           - 
~her    27.0   14.0   14.0   
'urces             
COPPER
ZINC
. CADMIUM
MAXIMUM
DISCHARGES
TOTAL
423
100.0
1,466
100.0
10.4
100.0
..

-------
Pa rameter:
(mg/L, except as noted)
Flow (gpm)a
pH (units)
Conductivity (Umhos/cm)
Temperatu("e (OC)
Ac id i ty (meq/ L)
Aluminum
An t imony
Arsenic
Cadmium
Calcium
Chloride
Copper
Iron, total.
Iron, ferrous
Lead
Magnesium
Manganese
Mercury (Ug/L
Potassium
Silica
Silver
Sodium
Sulfate
Thallium
Total dissolved solids
Total suspended solids
Zinc
Table 2
SUMMARY OF MAJOR SOURCES--
AVERAGE CHEMICAL COMPOSITION
(DECEMBER 30, 1983 - MAY 16, 1984)'
Richmond
POl- ta 1
73
0.6 to 1.4
195,000
26.5
1 , 150
1,190
0.295
34.5
10. 1
163
75
184
13,000
11,400
3.15
586
13.5
1.4
153
23.8
0.014
112
60,100
0.19
69,400
92
1,440
Lawson
Portal
50
1. 6 to 2.8
30,900
20.4
232
484
<0.02
4.6
2.4
178
5
55
3,560
2,930
0.21
329
9.0
<0.1
38
15.0
<0.001
31
13,400
0.03
19,000
20
350
Old-No.8
Mine Seep
89
1.7 to 3.1
7,600
16.2
131
509
<0.02
0.19
0.46
90
10
120
1,270
940
0.014
293
11.9
0.1
0.8
18.9
<0.001
6.1
6,800
<0.01
10,900
11
48.9'
Big Seep

2'77
2.2 to 3.1
1,350
9.9
16
47
<0.02
0.03
0.05
5
4
12.9
141
57
0.026
16
0.44
<0.1
<0.3
2.6
<0.008
3.3
690
<0.01
1,100
9
4.8
B(-ick Flat
Pit Bypass
35
2.3 to 4.6
2,610
11. 7
37
49
<0.02
0.47
0.41
44
2
14.4
369
259
0.70
68
1.8
<0.2
0.5
8.1
<0.001
3.0
1,530
<0.01
2,500
6
56.5
I
I-'
IU
I
~ . '..
. '

-------
- 13 -
a)
Boulder Creek
The existing water quality in Boulder Creek is quite
variable and highly dep~nd~t on rainfal~ and the
operation of the existing"Bav~der cement.t~on plant.
Boulder Creek water,quality data is presented in Table 3.
The sources of contamination along Boulder Creek consist
of the ~ollowing: '.
o
Boulder Creek Cementation Plant
The Boulder Creek cementation plant receives acid mine
drainage discharge continually from the Richmond and
Lawson mine portals through a series of pi~es and
fl~~es. Leaks and spills from the collection system
are addi~ional minor sources of ~ollutant discharges.
The quanti ty of the discharge froln this plant is
dependent on rainfall, and the quality is dependent on
whether scrap iron is being maintained in the treatment
plant. . .
It is estimated that the discharge from the Boulder
cementation plant contributes approximately 20 to 40'
~ercent 'of the copper, 90 to 95~ercent of the cadmi~,
and 90 to 95 percent of the zinc measured in Lower.
Boulder Creek.' .
o
Seeps
Numerous seeps exist along the Boulder Creek drainage.
The primary source of these seeps may be acid mine
drainage from the main orebody. Flows from these seeps
are greatly reduced during the summer months and some
may sto~ com~letely. The quality of these see~s is as
follows:
Parameter
Range
pH
Cadmium, total
Copper, total
Zinc, total
0.4 t~ 6.1 units
0.005 to 0.52 mg/l
1.0 to 13.4 mg/l
0.3 to 59.7 rng/l
The percent c~ntribution of seeps to Boulder Creak
is. listed on Table 4.

-------
TABLE 3:
Boulder Creek Water Quality
      Upper Boulder    .Lower Boulder 
      (Summec) (Winter) (Su:nmer) (Winter) (Spriny)
 Parameter  Sept 1983 Dee 1983 Sept. 1983 Dec. 1983 May 1984
pH, units  6.8 6.3  2.25  1.8   
Cadmium, total, mg/l 0.012 0.001  1.64  0.44 f' 0.65
Copper, total, mg/l <0.050 <0.050  3.52  1.45  1.10 
Zinc, total, mg/l 0.912 0.020  302.00  46.2  90.3 
.....
"'"'
. .
ii '.
'.

-------
o
- 15 -
Tailings Piles and Waste Dumps
~hese sources contribute pollutants ~rimarily during
storm events. In addition to dissolved m~~als and
acidic leachate, tailings and.w.aste materti-.11 are dis-
charged directly to. receiving waters in violation of
federal sus~ended solids limitations and water quality
standards~ -The ~ercent contribution of these soures
to Boulder Creek is listed on Table 4.
o
Other Sources
Other sources of metal~ollution ~robably consist of
subsurface drainage entering Boulder Creek and
dissolution of metal-bearing sediment in the creek.
Theseoth&-C. sources of ~ollution are estimated to be
as follows:
Metal
Copper
Cadmium
Zinc
b)
Summer
Percent
Contribution
Winter
Percent
Contribution
lb/day
lb/day

26
o
30
8.7
0.2
31.0
76
3
4
23
o
1
Flat Creek
The only identified source of ~ollutants discharged to
Flat Creek is the Minnesota Flats tailings pile. The
water quality of Flat Creek below Minnesota Flats is
given below.
Parameter
Flow
~H
Copper
Cadmium
Zinc
c)
Average
Range
280 '~pm

1.32 mg/l
0.018 ~g/l
1. 92 T1tg/l
58 to 9,000 gpm
2.6 to 6.5 units
0.003 to 7.63 mg/l
0.002 to 0.050 mg/1
0.48 to 9.02 mg/1
Slickrock Creek
The existing water quality in Slickrock Creek
variable and highly dependent on rainfall and
operation of the Slickrock cementation ~lant.
Creek water quality data is ~resented in Table
sources of contamination along Slickrock Creek
of:
is quite
the
Slickrock
5 . The
consist
/)

-------
11-'
- 16 -
TAB LE 4
Percent Contribution of Boulder Creek
Seeps and Ta i1 ings.Pi1~s Waste Rock.,
. Dumps", .' . . .' ..
Percent Contribution
(Range) .
Metal
Seeps
Tailings Piles and
Waste ROCK Dumps
Cadmium
--.
0.1 - 3
Copper
3.1 - 17
0.1 - 7
0.7 - 20
Zinc
0.1 - 3
0.1 - 4

-------
Parameter-
pH , un its
Cadmium, totaL, OIg/1
Copper, total, mg/1
Zinc, total, mg/l
",
I
!)
!
TABLE 5:
S1iekroek Creek Water Quality
Lower" S1 iekroek
Upper- Sliekroek
(Summer)
Sept 19B~

6.9
0.001
<0.05
(Winter)
(Summer) (Winter) (Spring)
Sept. 1983 Dec. 19tH May 1984
2.9  2.8   
0.21 0.056 0.073
27.1  8.50 9 - 4 7
lU.5  4.95 10.45
.......
-J
Dee 1983
6.3
<0.001
<0.05
<0.01 '
i "0

-------
- 18 -
.0
Slickrock Cementation Plant
The Slickrock cementation plant receives acid mine
drainage discharged contj.n\,ia~lly from the. Old-No.8 mine
seep. The quantity of the'discharge fro~.~he cementa-
tion plan is dependent on rainfall, and the quality is
dependent on whether scrap iron is maintained in the
treatmen~ tanks. It is estimated that the discharge frcm
the Slickrocl~ cementation plant contributes approximately
75 to 95 percent of the copper, cadmium, and zinc measured
in Lower Slickrock Creek.
o
Seeps
A few seeps exist along Slickrock Creek. The primary
source of"~etals in these seeps appears to be from the
old slide area, and from the hematite pile. It is also
possible that the source of these seeps may be AMD from
the main orebody. The major contributing seep is Big
Seep. The source of the seep area is groundwater and
surface water migrating through an old waste rock dump.
The quality of the Slickrock seeps is as follows:
Parameter
(mg/l)
pH
Cadmium, total
Copper, total"
Zinc, total
2.7
0.001
<0.050
0.01
to 6.5 units
to 0.30 rng/l
to 42.6mg/l
to 24.8 mg/l
Flows from the seeps are greatly reduced during the
s~~er and some may completely stop. It is estimated
that these seeps contribute 2 to 25 percent of the
metals in Slickrock Creek.
o
Tailings Piles and Waste Dumps
The sources along Slickrock contribute pollutants both
dur ino.] storm and normal t'ain fall events. The hema ti te
pile along Slickrock Creek contributes about 1 percent
of the m~tals in Slickrock Creek.
o
Other Sources
The other sources of pollution along Slickrock Creek
at'e the Brick Flat Bypass that flows down. the mountain
and enters the creek, subsurface dt'ainage, and dissolution
.of ~etal-bearing sediment in the creek. It is estimated
that these sources can contribute up to 5-30 percent of
the metals in Slickrock Creek depending upon the time
of year in which the discharges occur.

-------
,(.-
- 19 -
d)
Spring Creek
The existing water quality in Spring Creek is presented
on Table 6. The sourceofcbntamination~in Spring
Creek have been described In the Bou1der'C~~ek and
Slickrock Creek sections.
In addit(ori, there are probably sediment deposits within
the strea~bed, as observed along Slickrock Creek, which
also contribute to metals polluti~n.
It is not possible to fully assess the metal contri-
bution of the sediments, but it is estimated it is
relatively minor ~n relationship to the contribution
from Boulq~r and Slickrock Creeks.
e)
Keswick Reservoir and Sacramento River
The source of contamination in Keswick Reservoir are
inflows from Flat Creek and Spring Creek and sediments
deposited within the reservoir. The average water
quality in the Sacramento River is presented in Table'7.
The Sacramento River above Keswick Reservoir already
c~ntains ~etals. as shown in Table 7. After Flat Creek and
Spring Creek enter the river in Keswick Reservoir, the
concentration of metals are elevated up two to three
times. Due to the relative low concentrations of metals
and the variable flows from Keswick Reservoir, it is not
possible to accurately estimate the metals contribution
from Flat Creek and Spring Creek.
3.
Environmental Impacts
Due to past and continuing releases of AMD to receiving
waters, Boulder Creek, Slickrock Creek, Flat Creek and portions
of Spring Creek are essentially devoid of aquatic ,life. During
the RI, between 1,143 and 3,695 pounds per day of copper, zinc,
plus cadmiu~ were carried from the site into the Spring Creek
Reservoir. Of this total, between 623 and 3,328 pounds per day
of copper, zinc and cadmium were discharged into the Sacram~nto
River., These releases occurred over a period that is best
characterized as relatively dry winter conditions. The above
totals can be expected to rise significantly during normal or
above normal rainfall conditions.
Off-site, subsurface migration of contaminated groundwater,
does not appear to be a problem at this site. The hydraulics of
the site are such that the ~ine workings act as a drain, drawing
groundwater towards the mountain, and discharging it into adjacent
surface waters. .

-------
TABLE 6:
Spring Creek Water Quality
"
      ABOVE IRON MOUNTAIN BELOW IRON MOUNTAIN 
 Parameter  Average  Range Average   Range 
pH (units)   4.5 to 7.8   2.4 to 3.2 tV
Cadmium, total, mg/l  <0.001 to 0.001 0.10  0.03 to 0.16 a
Copper, total, mg/l 0.06 0.03 to 0.10 1.94  0.97 to 2.74 
Zinc, tota 1, mg/l 0.12 0.07 to 0.15 12.5  3.25 to 17.4 
. '.
. .

-------
-'
PalCIOOtet
(~J/L, except as not~~)
plJ (range of units)
Cond.lc t i vi ty (rmt\os/ em)
Tenpel'ature
Cadmiun, total
Cadmium, soluble
Copper, total
Coppe r, so lub Ie
II'on, tot a 1
Iron, soluble
Sulfate (mg/L)
Zinc, total
.Zinc, soluble
Table 7
SLJ.1MARY OF SACRAMEN'IO RIVER ~I1ORING
fEHRUARY 2, 1984, THROUGH JUNE 24, 1984
(Average of Detectable Values)a
Sacl'aroonto Sacramento Sacramento SaCramento
River Belew River Above River Belew Rivet' at
Shasta [Um Spring Creekb Keswick Lan Redding Intake
6.4 to 8.1 6.5 to 8.2 6 . 3 to 8. I 6.3 to 8.0
97 94 94 81
9.6 10.2 9.9 10.3
0.10 0.29 0.55 0.23
O.lH 0.29 0.41 0.37
3.5 6.5 8.5 15.8
3.7 4.6 4~8 4.9
224 339 5U5 470
63 76 66 66
3.7 4.6 5.2 6.3
14.H 24.6 37.0 37.4
13.0 26.3 30.8 39.8
. Sacramento River
Below Keswick [UmC
Average Range
2.5
1. 8 to 4.0
I \
tV
......\
24
10 to 52
196
2] to 500
, ..
aonly values r:eported above the detection limits were averaged.
i 0,
bSampling site appears to be influenced by backeddies fram Spring Creek.
cConcentrations monitorE:..'\.1 hy ~B during three spill events at Spring
Creek Reservl)ir'-..:Januar.y 19.78, January 1983, and March 198]. .
"
Note:
I\l> identifiable reasons for higher.' soluble concentrations conpared to
total concentrations ot sate constituents.

-------
- 22 -
4.
Impacts on Aquatic Life
a)
--
Introduction
While the occurrence of toxicityh.a.s been doc;;mented in the
Sacramento River, it is extremely difficult to quantify the
extent of the loss in a- river the size of the Sacramento. The
fishkills occur during the wet season when the waters are typically
muddy. Even with clear water, the river is difficult to survey
with widths as great as 300 feet, depths as great as 35 feet, and
fast currents that carry dead fish downstream. The most difficult
mortalities to observe in the river are the fish most sensitive
to metal toxicity - the early life stages of salmon and steelhead.
These sensitive salmonid lifestages live underneath the gravel as
small "sac fry" or in the river as small 2-inch "swim-ups" that
have emerged from tfteir nests.
- In addition to the occurrence of lethal toxicity, there are
more frequent occurrences of sublethal toxicity that could act to
reduce the overall productivity of the population. Effects such
as reduced growth rates, physiological problems, and diminished
immune response are known to occur due to exposure to heavy
metals. In a recent report to the U.S. Bureau of Reclamation,
the u.S. Fish and Wildlife Service estimated that the monetary -
value of the chinook salmon and steelhead trout runs produced
upstream from the Red Bluff Diversion Dam is approxmately $33.7
million annually. In addition, the economic value of these
fishery resources, with- attainment of fishery management goals,
is anticipated to increase to $72 million annually.
b) Discussion
Valuable fisheries resources, i~cluding migratory popula-
tions of sal~on, steelhead and resident populations of trout in
the Sacramento River are significantly impacted by the AMD from
the Spring Creek basin and have experienced numerous instances
of above normal mortality over the last 46 years. These incidents
which, have been directly attributed to ~~D from Iron Mountain
Mine were the result of observed mortality of adult fish in the
Sacramento River and calculated mortality of eggs and fry on the
basis of copper, zinc, and cadmium levels measured in the River
below Keswick Dam. Table 8 was developed by the California"
Department of Fish and Game (CDFG) and lists the documented
fishkills. CDFG has indicated that the Fall run of chinoo"k
salmon in the upper Sacramento River has ranged from an estimated
high of 400,000 in 1953 to a low of 22,000 with an average decline
of 87 percent in the last 20 years: that the average run of
salmon over a 20 year period showed a decline from 275,000 to
75,000 salmon. - This decline is attributed to several causes
including AMD from Iron Mountain Mine.

-------
TABLE. .
DOCUMENTED OCCURRENCES OP SALMON AND TROUT MORTALITIES IN THE SACaAKENTO RIVER ATTRIBUTED TO HEAVY KETAL POLLUTION PROM SPRING CREI~ DRAlNAGI
SHASTA COUNTY
~
Ob.erv.tton
Loc.tlon
Types of Mortalttles Observed
Sal.on Trout
Adult Juventle Adult Juvenile
Number
of Non.Utte.
Counted
1940
Kenett S.elter
W.ate Ptle
 11/44 lall. 'el'l'Y II
 Wtnter lall. 'el'l'Y 
 1945 
 04/49 lalla 'el'l'Y 
 04/22 Reddtna Are. 
I 19S5   
11/22 ~e.llltck Da. 
I II
IUS   
 02/21 Reddtna Al"ea 
 19S6 II
 01/19 Reddtna Aua 
 lU7   
 02/0s Reddlna Area 
 19S7 
 02/16- leddla, Ar~a 
 19/57  ,. 
 02/26 leddtna Area 
 19S7 
 09/26- leddtn, Area 
 10/S7 
UnknoWn
  200
II  
II II UnknolWll
II  Hundred.
.  42
. . II: UnknolWll
.   Unknovo
II   Unknovo
.   2S
.   2S0
.   2S,OOO
latt.ated
Nuaber of
Hortalt t tea
Method of
Obaervatlon
Conditton. tn
S.cr..ento Rtver
'10111 (ct.) Clartty
Sacr..ento Rtver lelolll Itealllick
"a.t.UIa Metal CODceDtrattona
(.a/1)
Copper
10% of apot ob.ervatton 3,000  0.061
.pavolna run  
 nuaerous c.ae teats   
  "   
 tnspect one .tle of bank   0.04
 spot obaervattons S;OOO  
 Itesllltck ftsh Trap and   
 btoa..ay of Sprtna Crk 4,000 lIuddy 
  lIIater    
 spot observatton 27,000 .ucldy 
 apot observatton l,SOO  
      ..
    2 ,600 .~ddy 
    2,600  
    12,000 .uddy . .
      ;
 .urv.y S 8J1.. of one bank 7,SOO auddy 
Zinc
~.
O.6S
I
I\)
W
--- I
.."

-------
TABU'
DOCUMENTED OCCURatNCES OF SALHON AND TROUT HORTALITIES IN THE SACIAHEHTO lIVER ATTRIBUTED TO HEAVY KETAL POLLUTION 'iOM SPRING Ci!E~ DRAINAGE
SUASTA COUNTY .
!!!!!...
Observatlon
Locatloo
Type8 of Hortal1tle8 Ob8erved
Sa180n Trout
Adult Juveoile Adult Juvenile
NU8ber
of HortaUUes
Counted
1940 lenett S8e1ter
Wa.te Pl1e
UnknoWil
11/44 Bal18 ,erry II
Wtnter BaUs ,erry 
1945 
04/49 lalla Perry 
04/22 leddtna Area 
19S5 
11/22 ICeawlck De. II
19S5   
~2/21 leddtna Area II
; 19S6
)1/19 leddlos Area 
1 19S7  
In/os leddtns Area 
\ 19S7 
)2/16- leddta, Arfa 
1:1.9/)7 
~2/26  ~ 
aedd1as Area 
[19SJ 
L   
:19/26- I.ddio& Area 
.0/S1 
200
II.  
II x . Unknown
.  Hundreds
.  42
. II It Uoknown
It   UnknoWil
x   Unknown
It   H
II   2S0
x   2).000
Est t.ated
HU8ber of
Mortalities.
30% of
spawtna run
Method of
Observation
spot observat10n
nU8erou8 case testa
In8pect one .tIe of ba~k
apot observations
leswick 'ish Trap 81'1d
bloaasay of Sprina Crk
water
spot observ8tlon
spot oba.rvation
Conditions 11'1
Sacr..el'lto liver
'low (cfs) Clarity
3.000
S.ooo
4.000
27.000
1.S00
2.600
2 .600
12 .000
.urv., S 811.. of one bank 7.SOO
auddy
.uddy
8uddy
,
8uddJ
IlUdd,
Sacr..eoto alveI' lelow leswlck
Keltiaua Hetal Coacentratlons
(81/1)
Copper
0.061
. .
0.04
--- .
. .
. '.
Zioc .
0.6)
I
ru
--- .j:::"
I

-------
- 25 -
According to the CDFG, the decline of the upper Sacramento
River salmon and steelhead stocks represents a sizeable dconomic
loss to the state due to the lost availability of these fish to
the commercial and sport fishery.. At~times, the u,pper Sacramento
River produced half of the state's Chinook salmon~'. 'Economic
studies conducted by CDFG and the U.S. Fish and Wildlife Service
have estimated that the continuing economic losses associated
with the present d~pressed population levels of salmon and stdel-'
head relative to the catch levels in the past have a net annual
economic value ranging between $30-$40 million. CDFG believes
that tha incremental mortality caused by discharges from Iron
Mountain Mine are responsible for a significant share of that
economic loss.
Of part.icular concern is impact of AMD on populations of
winter run chinook'$almon, one of four genatically distinct
populations of salmon in the river. According to the CDFG, the
winter run population in the upper Sacramento River has declined
precipitously in the past 20 years to the point where the National
Marine Fisheries Service is evaluating a petition requesting
that t~e winter run chinook be listed under the Endangered Species
Act of 1973. The CDFG has apprised EPA that one of the priority.
actions that would be included in any winter run restoration or ..
recovery effort is:correcting the heavy metal pollution problem-
caused by Iron Mountain Mine. Additionally, the king salmon'
runs in the upper Sacramanto River have experienced a 50 percent
decline over the past 30-35 years, with heavy metal pollution
from the Sprin~ Creek basin being cited as one of the major
responsible factors.
Because of the variations in the operation of the Shasta
unit (Shasta Darn, Keswick Dam, Spring Creek Debris Dam, and the
Spring Creek hydroelectric power plant), and unusual climatological
conditions, there has not been any long-term undiluted spills and,
thus, no observed mortality of adult fish in the Iron Mountain
Mine area since 1969. There is, however, a shared concern among
state and federal regulatory agencies that as competition for
Shasta Lake water increases in thd future, the U.S. Bureau of
Reclamation may be held more accountable for ensurin~ that only
the authorized uses of the water are allowed; this could result
in the lack of adequate dilution water being made available to
avert fishkills.
5.
Potential Public Health Impacts
The degree of human risk associated with the AMD from the
'Iron Mountain Mine site depends on the nature and dxtent of
exposure. The California Department of Health Services (Depart-
ment), in an endangerment assessment prepared on August 22, 1984,
for this project, discus~ed the types of exposure that represent
a potential threat to public health. These included the following:

-------
- 26 -
Dermal Contact: Near its source, the ~~D contains sulfuric
acid in concentrations that could cause serious eye injuries
and skin irritation through direct exposure. Although the
study area is located in rugged ~nd ~emote terrain, the
potential for human exposure canno-t. b~ ruled out;,:,~ 'The area
is located between two heavily used National Forest areas.
Areas adjacent to the -mine property are frequently used for
recreational purposes, especially for off-road vehicle use.
The mine owners have complained of tres~assing and vandalism
problems on the site. The AMD is diluted as it enters Boulder
Creek and Slickrock Creek and there is a less serious risk
with regard to dermal contact with increased distance from the
source.
Ingestion of Water: - The potential for direct ingestion of AMD
in the upper studi--area is considered small for two reasons:
a) once the AMD enters the creeks, there is a discoloration
associated with the precipitation of iron, and b) the remoteness
of most of these areas limits access.
Cadmium concentrations measured at_the Redding raw water intake
have not exceeded the drinking wa~er standards. A potential
public health threat does exist due to the elevated concentra-
tions of metals in the Sacramento River. Levels of cadmium in-
the River have approached and occasionally have exceeded the
proposed EPA drinking water standard of .005 mg/l.
Ingestion of Fish: Ingestion of fish taken from Keswick Reservoir
does not appear to represent a significant public health threat
according to an analysis which expanded the endangerment assess-
ment prepared by the Department of Health Services. However,
the Department indicates that the long te~n risk from the
bioaccumulative toxin, cadmium, should not be underestimated.
The Department estimates that 50 percent of the body burden of
cadmium is located in the liver and kidney of fish, with 3nother
50 percent distributed across other tissues. Humans also
accumulate cadmium in the liver and kidneys over their lifetime.
It i~ felt that, without remediation, mine effluent will continue
to be deposited in sportfishing areas of the Sacramento River
and the concentration of cadmium i~ fish will continue to be
elevated above normal levels.
6.
Impacts on Public Welfare
Shasta Dam was constructed under the authority of Public
Law 84-386, as part of the Trinity River Division, Central Valley
Project. This law created several specific uses of Shasta Lake
water, including the generation of hydroelectric power, water
sales to farmers, and use as a drinking water supply. Shasta
L~ke also has a recreational value associated with tourism,
boating, fishing, and swimming.

-------
- 27 -
,,~ '
, '.
Release of Shasta Lake waters for pollution control in the
Iron Mountain Mine area is not an authorized use of these waters.
-Nevertheless, since the construction of the Shasta Dam/Keswick
. Dam/Sprlng Creek Debris Dam water management syst~nr, Shasta
Lake waters have been, and continue'to-be released~f6~ this
purpose, when waters can be provided without adverse impacts to
other proje~t requirements. By controlling the release of these
waters the U.S. Bureau of Reclamation (Bureau) has assistad
other federal and state agencies, in promoting fishery resources
in the Sacramento River.
Although it is difficult to quantify the exact value of
Shasta Lake water, the Bureau has estimated the revenue that
would be lost by releasing Shasta Lake water for pollution
control. This was accomplished through the use of a mathematical
water model that assumed that water that wasn't being released
for pollution control would be sold for municipal and industrial
purposes. Based on the Bureau's analysis, it was estimated that'
meeting less stringent standards (the original water quality
standards that were in effect prior to the stata adopting the
existing water quality standards) in the Sacramento River would
result in an annual loss in revenue from the U.S. Treasury of -
about $32 million, and that fish saved by releasing this additional
dilution water would have an annual value of $1.4 million. Meeting
the proposed Superfund metals levels, which are substantially
lower, would cost about $456 million in dilut(on releases, ~ith
fish savings of about $9.6 million per year. Without remediation
in the form of source control and treatment, releases of Shasta
Lake water will be required until such time as Iron Mountain
Mine ceases to discharge AMD.
V.
ENFORCEMENT ANALYSIS - Confidential
(See Attachment)
VI.
ALTERNATIVES EVALUATION
A.
Introduction
The major objective of the feasibility study was to evaluate
remedial alternatives using a cost-effective approach consistent
with the goals and objectives of CERCLA. A cost-effective r~mediaL
altern~five i. defined in the ~ational Oil and Hazardous Substances
Pollution Contingency Plan (NCP) 40 CFR ~300, et.seq. as the
alternative that effectively ~itigates and minimizes threats to
and provides adequate protection of ~ublic health and welfare and
the env i ronmen t. Except as prov ided in See t ion 300.68 ( 1) ( 5) ,
this requires the selection of a remedy that attains or exceeds
applicable or relevant and appropriate federal public health and
environmental requirements that have been identified for the
specific site. In selecting the appropriate extent of remedy,
EPA is directed to consider cost, technology, reliability, .
administrative and other concerns, and their relevant effects 9n
public health and welfare and the environment.

-------
- 28 -
The feasibility study process included the following steps:
(1) identification of general response actions, (2) identifica-
tion of target clean-up levels, (3) assembly of the universe of
, technologies relevant to the respo.nse.actions, (4) ..retention of
the surv iving technolog ies as compon~n.t ,act ions, (5 r assembly
, of the component actions into combined alternatives, (6) initial
screening of the combined alternatives, and (7) detailed analysis
of survivirtg'combiTIed alterr.ati~es. Nine combined alt~rnativ€s
(CA-l to CA-9) underwent very detailed analysis. Three alterna-
tives were considered in less detail and were included in the
final alternatives matrix: Alternatives CA-IO ($1.4 billion),
CA-ll ($350 million) and CA-l2 ($263 million). The feasibility
study results are presented in more detail in the following
paragraphs.
Based on si ta 't)'ackground information and the nature and
extent of the problems from che technical investigation to date,
the key general objectives for the Iron Mountain Mine site were:
To minimize off-site contaminant migration via surface
water runoff and seepage, and
To mitigate impacts and minimize the migration of
contaminants that have already moved from the site
through receiving waters.
The two areas targeted for remediation and selected general
response actions were:'
Areas of Remediation
General Response Action
Ore bodies and underground
mine workings
No action, recovery, treatment,
source control, and disposal
Surface water
No action, water management,
treatment, and disposal.
The contaminants of primary concern at the Iron Mountain
Mine site are copper, cadmium, and zinc because: a) these
contaminants have been detected at high levels at the source and
in surface waters receiving discharges from Iron Mountain Mine,
b) acute dosages of these contaminants have been found to result
in fis~.kills: sub-lethal impacts have, among other things,
resulted in reduced cates of growth and accumulations of metals
in fish tissues: and c) even when toxic levels are not reached,
these metals act to depress the overall productivity of life in
Keswick Reservoir and the Sacramento River.

-------
- 29 -
B.
Site-Specific Action'Levels
Three sets of target clean-up levels were considered as
primary cleanup objectives for Iron.M'ountain Mine;,.,
! . . .
. .
1.
Implement remedial actions to achieve the following EPA
Water Quality'Criteria for Protection of Aquatic Life below
Keswick Dam:
Copper: 5.4 ug/l
Zinc: 47.0 ug/li
Cadmium: 0.55 ug/l
2.
Meet Regional agard Basin Plan Objectives for copper,
cadmi~~ and zinc in the Upper Sacramento River:
Copper: 5.6 ug/l
Zinc: 16.0 ug/li
Cadmium: 0.22 ug/l
These objectives are based on a series of intensive studies.
conducted by the CDFG. According to CDFG, implementation
of remedial activities that meet these objectives would'
provide safe levels having no chronic or acute effect on
aquatic life in the Upper Sacramento River.
3.
Meet background levels (established by the water quality
upstream of the confluence of Spring Creek and the Sacramento
River) :
Copper:
Zinc:
Cadmium:
3.5
14.8
.1
ug/l
ug/l
ug/l
The secondary objective is to reduce the metals ~oading from
the Iron Mountain Mine site to receiving waters.
C.
Technology Development
A variety of technologies was examined with regard to
technical'feasibility, degree of publ'ic health protection
afforded, environmental impact, institutional concerns, and
cost.
The applicable technologies identified were then combined
to form remedial action alternatives that addressed source control
and treatment of AMD at the mine and surface water management.

-------
- 30 -
Preferred technologies for the various components that
addressed source control and water management are identified in
Table 9. . .
.'
. .
.. .
D.
Components for Detailed Analysis
The following discussion describes the components that were
later combined into alternatives (see Table 10). Table 11 .
presents the technical, environmental, institutional and other
considerations for each of the components (#1 through #11) .
Component #1. Solution Mining (Proposed by IMMI)

Toward the end~of the RIfFS, Iron Mountain Mine, Incorporated
(IMMI) submitted a concept for a proposed metals recovery operation
at Iron Mountain Mine. This proposal was developed independent
of EPA's feasibility study by consultants for IMMI. This proposal
included the in situ leaching of the sulfide orebody to extract
copper, zinc, iron, and precious metals, and the recovery of the
base metals as industrial and agricultural chemicals.
The basic principle of the IMMI proposal is to seal the
Richmond and Lawson portals, recirculate AMD back into the.
mountain and draw off 2,000 gpm of concentrated acid mine water
from in situ leaching, and treat it at -a copper extraction plant.
An acidified 1,800 gpm stream would be recycled for reinjection
into the orebody to enhance metal leaching. A 200 gpm bleed
stre~n is treated in the metal salts recovery plant and a waste-
water treatment plant prior to discharging to receiving waters
or irrigation.
Component #2.
Partial Capping
The purpose of capping and constructing drainage ditches
around cracked and caved ground areas above th~ Richmond orebody
is to reduce the water available for generati,.:>n of AMD by inter-
cepting surface water and directing it away from the orebody.
This source control method is applicable pri~arily to the Richmond-
Complex.orebody as this is the only source that shows significant
contribution fro~ surface water inflow. Cracked ground, caved
ground, and other known primary conduits for inflow would be
surface-plu~ged and sealed to reduce the rapid inflow of water
into these areas. Su~face water would be intercepted by a system
'of lined ditches and directed away from the'orebody to reduce
the potential of surface water finding a path of rapid inflow.

-------
Table 9.
General Response
Action
OREBODIES AND MINE
WORKINGS
No Action
Recovery
Treatment
Disposal
SURFACE WATER
No Action
Water Management
Treatment
Disposal (AMD)
Disposal (Solids)
-31-
.. .
Available Technologies
Technologies
:. ..
. .
No action
,"
Mine the orebody using open pit,
underground, or in situ methods
"'''.'
In situ methods without metals
recovery, and the use of sur-
factants or other inhibiting agents
groundwater barrier walls, ground-
water interception, pumping, and
revegetation of disturbed areas.
Injection of Low-density concrete
in underground mine workings.
Landfill
No action
Transbasin stream diversion (pipe,
open channel, flume), local stream
diversion, enlarge existing
storage, construct new storage, and
modify CVP operating plan
Precipitation (utilizing lime/
limestone, sodium hydroxide, soda
ash), biological neutralization,
bogs, sulfide precipitation, starch
xanthate treatment, clarifier
thickener, aeration, chemical
oxidation, biochemical oxidation, ,
electroflocation, ionic flotation,
carbon adsorption, solvent.
extraction, sodium aluminate, copper
cementation, electrowinning, filtra-
tion, 10n exchange, reverse osmosis,
electrodialysis'
Solar evaporation, deep well injec-
tion, controlled release, and deep
water injection
Landfill (on or offsite), solids
disposal in mine workings
...

-------
-32-
Table 10. Components for Detailed Analysis
.'
:' ",.
SOURCE CONTROL
. .
o
Partial ca:;:,ping
o
Complete capping
o
Groundwater interception
o
Injection of Low Density Cellular Concrete in
underg~ound Mine Workings
TREATMENT
o
Treatment of the three major sources
o
Treatm~nt of the five major sources
o
Treatment of five major sources and other sources
in Slickrock Creek
o
Treatment of the five major sources plus other
sources in Slickrock Creek and Boulder Creek
WATER MANAGEMENT
. . 0
o
Diversion of upper Spring Creek to Flat Creek
o
Dive~sion of South Fork S?ring Creek to Rock
Creek
o
Enlargement of Spring Creek Debris Darn
Diversion of Upper Slickrock Creek
around tailings piles

-------
("~ ..I
."--1...
9OUJK:E COInIlOL
COIIIII.'.
C8ft\I""
1W11.1 c.wl...
'D,ect'OD 01 1..-
---It, ceU..lu
CIIIIC..t.
TAALb _1
Technical. Environmental and Iosqtutional Considerations for Remedial Action COOIponents
1I8c:Ia1c:a1 C-..
...,.-_.1 eo-n
Thl. .1'.'D.".e I.
..peelo4 ,. ... 90
pe.<:tnl .fleen.. ID
1..'e.cep'I..." IDIII-
II ." oro and sO pe.-
cenl .lIee".. ID
.e4ucln" AICI II..
111.-'->1>4 po.I.1.
C.......I .e""..'.I,
".eUo4 to
po'''' 1.1 .o4Itct I.... I. 0611
CDOI.. Iba '~~_.I .1'..-
..,.... .... ..vDI.lcaa. 0611
coa.. barODd . be 10-,...
...hoalloa peUod 10. 11>1.
.1ud7.
,.1. .11....tl.. .1...lall..
...t. .t .... MW' 08, booo-
...r, II cou 14 ..... ..
.".=1 GD pol..t... lu'~
a...I"9 0' lhe o,d>o4r.

-------
,-
..~ It
AU_U..
Technical,
TABLE 11
Environmental and Ins titlJtiona1 Considerations for Remedial Action C'.omponents
hdlalcal C-..
..II'_t., c:o-n.
..., ...., I_I C-..
ou.. c-....
Gr-.....,..       
..'.'''''''1- naa. .".'_110. a. ... 8jI.a..... ."1/.0." ..,.. ... .. JO' I.....,. lep.o." 1'.01..,'108 
 ..peel... I 0 be to CUR81.lIACleblll'r qyalll, a. I" Sec..- "08 1.."1..11_1 o. CUr o. lIecIOa", 
 ,..ceRl .1I.cU.. a. 1'."'1_. ...10...........1'1", ...,.."_h. d.a....", ..1.. 
 a..I..ceval"i i'OII04-  I. a..o.... ...., ae  euwl,. 
 ...t.r. c.'lIIOa p,.~  ........,.   
 dael accu,.'.I, lbe     
 0....11 .11 eel 08     
 .lIb.. ...t.r OJ"     
 ..,... .educlluo.     
      .' 
     "  
 "1gb 1...1 o.     
 ....., ...,.."84     
 '0. _.k I..     
 -.9.-""     
 a.....,. ...     
       I
       LU
       .$::"
       I
llU1IEIIf       
.... .J...       
--.c.. Uti I h.. 1"""" II.. ee.I..... 1"'''..4 ...... ~I. .1..... '."'.1.. 1"'0..4 p...I.ClaGG 
 '.Cbnol..". ....... ....,..10..11, II, a. ... a.n_.... ,.... Iba. ,.oc... ..a CII, ..a 
   ...""ac... .a... '.."I.a.., a. .., be c-adc..4 . ....a..... d.a..ka... 
    1"."..41 "".Ilc b.......... "..1. and ...... ...,,,1,. 
    b."I1... .....a.. ......a..  
     ,...a.. a....  
      . .. 
'h. .J...      ; 
s-.c.. U. II II... .... ...a-. 1..........41 ".... ,...1- 11114.. .........41 l8plove4 p.'occ~llon 
fI... ..b.. prov.. c_.nue..loua" a" a. ,.. a.c.....,. ..... 'bl. ,.oc... ... CI., .., 
'''chocll ..chn..I...,. ".""1.... ..... ....... a.. a. .., .. CGG.a"n4 . 'eddl...'. d.ankl... 
--re..    a........ .~,ac ........... ...... and ...... ."P8'I,. 
    ..1111.,. .....a.. ..,...a..  
     ,...aua...  
'h. ~...       
s-.ce. Utlla... IIu ...a_. I........ ...a.. ....1. II"'.. .."'.'.4 I.,...ud ".,,'ccII- 
,I... "'''I' ,....... con.""C'.bUU, I', a. ,be ..c.....,.. ,.... I.a. ,.oc... ... CII, ... 
.1 achocll .... '.Cbnol"IJ. ,.""1_.. ..... .....I,a.. a. .., .. c_adc.ed . '."In.'. d.lnk I.. 
--141..    a........ ....tlc .......... ...,. .... ...1.. ."1'1'1,. 
......c..    ."11.'. '.'11". ......a..  
     ,...a.. a.,.  

-------
fl. I t
AIt~t &..
TABL. 1
Technical, Environmental and InatitlJtional Considerations for Remedial Action COOlponents
1iIodIa&cal c-..
...h-t.1 c..-..
"'0.- t8daDolovr.
Yn8'-t . o. a.u-
-... _OM
UUd18aD4 po..t.l.
.....- port.t. ....
014 Itg. . .-pI
.Itb ttee/t&_atoae
t....t_at
""TU~
Dh...I- 01
.."... 11'..10'
end.
Utl'lace pro"."
1.""'010" "'Ich

iovolve. AG
..ch_Ical

.,,,lpeeOI.
P.....I- O.
6001". ,,,"'
lipll"'l
CI_.
OI..lal... 01 ~..
SUcuoca c....
..C1U84 t.Ht898
D>1"'~Dt ...
..,..1"'1 c...,
1181>.. la Pa8
Utili.... "..0....
tecboolO\l}' .bleb
'..01.... DO
eeca..olc.1

..,..1'-0' .
D&atl8l"l>>8808 0" 1- ...
aquetac ... t.......tr&al
0.-",&- 8D4 "'18.t ....a..
C1IIG8trw:ta..
810 .crlou.
c"".ulIClabUIt,
1'....,1.... .....
loc...a.. '100410'
....u....a' .1... "a'
(..eI, -.
L au.. . pe..1 II 10'
...........
I.......... ...IU
~III, ID '1.. C...cb
.... ,.. S.c.....OI"
II.... ..c...I.lo. I.
Cllbaac_". o.
........ c "10"81.
III> ... 1008

conal."ctebill',

''''''1_-. ....t
.U I '''<1'''''.
UIS8II 81''''' ....1 .
-'..0'" ..t.r
...IU, a. tile
lacr....to ......
'..'UoI,_1 C:-..
81.. ..........04 h- 'bl.
P"-.. -, be <»eo&"',,'"
Ilea....... ...t. ... hqUh.
..t..e&.. pel"8lttl88.
r;
'..ope..., .c,,,laltl-
.., ... ...........4
4owoa...... - '1.1
e....k H p..ope...,
.1_. u..k ..
It-.4.
hope.t, ~Ialtl...
-, .. ""''''04
"""t..-... 8DQ
e.... II ,rope..',
.1.... cr... a.
1100080.
08... C-...
Ibt. .II.~'.. ~IG
"8\1\1'''' p8rpet_1 OUt co...
a... bud.... al.. 118,IIOCI
tbe JO-,... ~'c pe..&od
u884 ID Ibla 888',.... Ooe.
DOl .IDI81.. ...t. .1 I"
aOUfD8.
POI.o.I.1 '1-'...
10 ".1 C...k.
Incr...ad 8e1.1.
COACcolull.... 10
1,.10' C.-, .....
rclal.. loe....a.d
b...,d. ...001..ed
..lib bll8ah c...~.cr.
Mowcver. chere-'. 80
0....01. bcocU. 10
puIoUc huilh.
aapecla o' the CI.,
... "'''4In. J. ""'1".
".'e, .
I
lAJ
U1
1
;.'.,.
. .

-------
- 36 -
The caved ground areas would be filled and sloped to maximize
runoff. A total of five caved ground areas would be filled;
this will require a total fill quantity of approximately 40,000
cubic yards of material. To reduc~ vertical infil~ration
into caved ground areas, the areas wou~q be filled-and graded to
drain using a filter material and low permeability layer.
Component #3.- Complete Capping

This component involves caf>pingapproximately 15 acres
overlying the Richmond orebody. The alternative would require
stripping and gr~bbing of some of the existing vegetation,
filling of the caved and cracked ground, some regrading of the
site to limit slopes where possible, and construction of benches
to divert water to adjacent drainages. A soil-cement surface
barrier would thenIJe applied to the area.
The six caved ground areas, totaling approximately 2 acres,
would be filled with cobble- to sand-sized materials prior to
applying. the soil-cement. Two cracked ground areas would be
filled 'with a slush-type grout and cobble- to sand-sized
materials, with a low-permeability. seal at the ground surface. -
The lower portion of Brick Flat Pit would be filled similar
to the caved ground areas to allow gravity dr~inage of water
from the pit area.

Interception ditches and drains would be provided to intercept
surface water and divert it away from areas where the orebody is
exposed to surface runoff.
Component #4. - Ground Water Interception

In this component, groundwater moving toward the Richmond
orebody would be intercepted by a tunnel and drill holes on
either side of the orebody. Through gravity flow, the water
would then be conveyed to Boulder Creek. Approximately 1,250
feet of the existing Richmond tunnel would be rehabilitated and
used as the access tunnel for constructing the two new tunnels
on either side of the orebody~ These new tunnels would be
approximately 7 feet in diameter and 1,600 feet in length.
. -
A vertical system of drill holes would be installed
approximately every 50 to 100 feet along the two new tunnels and
would act as groundwatar interceptors.
Component #5. Injection of Low-Density Cellular
Concrete Into Underground Mine Workings

,This component consists of filling the underground mine.
workings (UMW's) with a low-density cellular concrete (LDCC) to
eliminate or reduce the formation of AMD. This objective could

-------
- 37 -
be met by LDCC injection if :exposed ore could be sealed in the
UMW's or if discharge could be reduced sufficiently t~ raisa the
groundwater table above the orebody, thereby minilnizing available
oxygen for the formation of Al\\D. .'
. .
."' ...
In developing this component, it w~s assumed that a conc~ete
batch plant and materials stoiage facility would be constructed
near the Richmond .portal. Stockpi.led at the site would be cement,
chemicals for produ~i~g a low-density concrete (this' chemical is
a foaming agent which causes tha concrete.-to expand and therefore
reduces its density), and aggregate. The aggregate for the LDCC
would be composed of Minnesota Flats tailings, available onsite
hematite material, and waste rock and slide material from the
Big Seep. This would reduce the cost for aggregate material and
also reduce existing sources of surface runoff pollution. Water
containing AMD would be conveyed to the batch plant, where it
would be neutraliz~a and used in the manufacture of the LDCC.
As the LDCC is produced, it will be pumped into the mine
workings and allowed to solidify. This is intended to coat the
exposed ore and plug the UMW's, which could bring the water
table back to historical elevation, and eliminate or reduce AMD
formation. Rehabilitation of the Richmond wor!dngs would be ..
required to provide access needed to effectively inject the LDCC.
Rehabilitation of the Hornet workings and others may also be -
necessary. .
It is expected to take two years, op~~ating 24 hours pe~
day, to fill the workings with LDCC.
Component #6.
Treatment
o Sub-Component 6 (a) Treatment of AMD from Three
Major Sources
This component consists of collecting AMD frarn the Richmond
portal, Lawson portal, and Old No.8 seep, and conveying it to a
lime/limestone treatment plant for treatment. This component
assumes that the sludge produced from the treatment plant would
be dewatered and taken to Brick Flat Pit (BFP) for disposal.
It is estimated that SFP can accomodate dewatered sludge produced
by treating the three major sources over a 30-year period.
For ease of transporting sludge to BFP, the li~e/limestone
treatment plant would be sited ~t the old processing facility
near the Richmond portal. AMD from the Old No.8 seep mayor
may not have to be pumped to the treatment plant, depending on
final site layout and elevations. .
BFP would be modified with an embankment to provide storage
of the sludge produced from the treatment process. The walls of
the pit would be coated to form a relatively impervious liner.

-------
- 38 -
In conjunction with the treatment plant construction and
modifications to BFP, road improvements to these sites will have
to be constructed.
.'
t- ...
. . ,
~Sub-Component 6 (b) Treatment of AMD from Five Major
Sources of Pollution
AMD from the five major sources (Richmond portal, Lawson
portal, Big Seep, Old No.3 seep, and Brick Flat pit diversion)
would be collected and transported by gravity to the treatment
plant. The maximum flow for this alternative is estimated to be
4,000 gpm. The expected overall removal of metals leaving the
site with this alternative is 72 percent of copper and 86 percent
of zinc and cadmium.
--.
Small diversion structures would be constructed at Big Seep
and the Brick Flat Pit diversion. Flows from these five sources
would be combined into a PVC pipeline, which would be buried
along the route of the existing access road and transported
approximately 9 miles to the treatment plant located on 90 acres
of land immediately adjacent to the Sacramento River.
The neutralization treatment process consists of the follow-
ing units: .
1.
The addition of limestone to the AMD to increase the
pH to 4.
2.
Fifteen acres of first-stage settling lagoons to remove
sludge.
3.
The addition of lime to raise the pH to 8.5. The
addition of air for the oxidation of soluble ferrous
iron to insoluble ferric iron. .
5.
A heavy solids separator, together with 14 acres of
second-stage solids lagoons for sludge removal.
The lagoons would be designed to allow the
during the summer months. The remaining solids
hauled to either a Class I or Class II landfill
adjacen~ to the treatment .plant.
sludge to dry
would then be
constructed.
~Sub-Component 6 (c) Treatment of AMD from Five Major
Sources Plus Other Slickrock Sources
The component is essentially the same as Alternative 7 (b)
with the exception that the sources on Slickrock Creek will also
be collected and treated with the five major sources.
..

-------
- 39 -
.- t
The collection system on Slickrock Creek would consist of
an upper diversion dam which bypasses clean water around the
reach of the creek that is impacted by the other sourc~s including
seeps, slide debris, and tailings,~iles.

. I . . . .
.:~ '. .:..
A second diversion dam ~ould be constructed downstream of
the other sources to ~ollect the flow from Big Seep, Old No.8
Mine seep, 'and Brrc~ Flat Pit diversion, together with the other
sources. This AMD would flow by gravity and would be combined
wi th the piped flows from Richmond portal. .and Lawson portal.
The combined flow would then be routed to a lime/limestone
treatment plant.
The maximum hourly flow for this alternative is estimated
to be 42,000 gpm under 1978 conditions. This would require that
the transport pipekine and limestone and lime treatment structures
be enlarged above those estimated for AlternativeS. The size
of the sludge lagoons would remain approximately the same. The
expected overall removal of metals from the site with this alter-
native is 86 percent of copper and 93 percent of zinc and cadmium.
o
Sub-Component 6(d) Treatment of AMD from the Five
Major Sources Plus Other Boulder and Slickrock
Sources'
With this component, the five major sources and all other
sources on Boulder Creek and Slickrock would be collected and
treated. Upper diversion dams would be constructed on both
Slickrock and Boulder Creeks to divert clean water around the
areas of the creeks that are being contaminated by the other
sources.
Downstream diversion dams would be constructed to capture
and divert the remaining flows in the streams. The flows would
be combined and would flow by gravity to the treatment ~lant. .
The maximum hourly flow for this alternative is estimated to
be 110,000 gpm under 1978 conditions. As with Alternative T-lb,
this will require increasing the size of the ~i~eline and the
treatment plant structures. It is expected that the overall
removal of m~tals from the site with this alternative would be
essentially 100 percent.
Sub-Component 6 (e) Treatment of AMD from the
Three Major Sources with Copper Cementation

With this component, the three major sources of pollution
(Richmond portal, Lawson ~ortal and the Old No.8 mine seep) ,
would receive copper cementation treatment. Copper cementation
is an oxidation-reduction reaction whereby solvated (in solution)
copper ions are exchanged for elemental iron (usually provided
as scrap iron). This scrap iron, preferably well shredded to
o
;

-------
- 40 -
obtain good contact with the liquid waste stream, is placed in a
basin large enough to produce fairly quiescent conditions. As
the wastewater is passed through the basin, iron is dissolved
into the- streal\\ and a copper sludg~ sEattles out. ~J'\is process
is currently being practiced at Iro~ Mquntain Min~-and is achieving
good recovery of copper (as high as 95 per~ent plus removal in
one of the cementation plants)'.

Component #7. Dlversion of Upper Spring Creek
This component would reduce flow into SCDD by diverting
upper Spring Creek to Flat Creek. A l6-foot-high, iOO-foot-
long, rock-filled diversion dam would be built on Spring Creek
near Minnesota Flats to divert up to 800 cfs of flow.
An 8-foot-diaI'l\~t:er tunnel, with a hydraulic capacity of
approximately 800 c~s, would be constructed on the upstream side
of the dam to divert the flow into the Flat Creek watershed.
The length of this tunnel would be approximately 600 feet. A
chute and energy dissipator would be constructed between the
diversion and the point of discharge into Flat Creek.
Component #8. Diversion of South Fork Spring Creek

This component would reduce flow into SCDD by diverting the
South Fork of Spring Creek (SFSC) to Rock Creek. To accomplish
this, a 10-foot-high, 60-foot-long diversion structure would be
built on SFSC. About 4,000 feet of 54-inch conduit would
carry the diverted water to Rock Creek. The hydraulic capacity
of the diversion system would be 250 cfs.
Component #9. Enlargement of Spring Creek Debris Dam

The existing Spring Creek Debris Dam would be enlarged at
its present site. The present storage capacity of the dam is
5,800 acre-feet. This would be increased to a volume of between
7,000 acre-feet and 23,000 acre-feet depending on which cleanup
objective is selected.
Component #10. Upper Slickrock Creek Diversion Around
Tailings Piles

The purpose of this diversion is to reduce the volume of
flow from the Big Seep pollution source. It is believed that as
Slickrock Creek flows over and through the pile of slide debris
that fills the canyon above the Big Seep area, a significant
portion of the flow enters the loose slide material and reappears
in the Big Seep area. Analysis of the Big Seep hydrograph has
led to the conclusion that a significant reduction in the flow
and pollution load from Big Seep could be achieved by intercepting
and diverting Upper Slickrock Creek before it comes into contact.
with the slide debris. .
I

-------
- 41 -
. .
",.." ;-~..:_". ,,"'.,,:,:;,;4h.i 5:--';;"compo net1:t;wo.u1 d,"",.i'nv....Q.l.vce;~o;~..'.".d.iv..eZ::-.$i Qn~.;..s.tr.uC.t.u.r"I:!~,~..,,.aJ\..~..';",. "'....~ .C.~..~.,. - ~~~-",~oc
lS-inch PVC pipeline, and an energy dissipator at the end
of the pipeline. Upper Slickrock Crek flow would be diverted
around the slide area to the lowe~ reach of Slickrock Creek.
. . ~ ".
, . .
A numerical water quali~y model was used to determine
if any of the individual components could achieve either
California 'Basin ?lan Objectives or EPA Water Quality Criceria
for Protection of Aquatic Life below Keswick Dam. The model
used a mass balance approach to account for heavy metals ~s
they are carried in the streams (Boulder Creek, Slickrock
Creek, and Spring Creek) through Spring Creek Reservoir and
eventually to Keswick Reservoir. The model regulated discharges
from Spring Creek Reservoir such that when the discharge is
mixed with Sacr~~ento River water released from Shasta Lake,
water quality objectives are met below Keswick Dam.
The results from the operation of the model indicated
that the aforementioned components generally could not achieve
either set of water quality objectives below Keswick Dam (or
points upstream) if implemented individually. There are two
exceptions, however. Conceivably, the Spring Creek Debris
Dam could be enlarged to such a size that the objectives
could be met through flow equalization alone. Or, the
objectives could be met by using the Spring Creek Reservior '
as a collection basin and treating all liquids in it by ~ime'
neutralization. This latter approach could achieve background
levels for metals below Keswick Dam at an estimated cost of
$263 million. Treatment of the liquids in the Spring Creek
Reservior will be carried forward as an alternative. Varying
the capacity of the Spring Creek Reservior by varying the
height of the dam will be carried forward as a component of
many of the alternatives to be considered. It was felt that
varying the size of the Spring Creek Debris Dam should not
'stand alone as an alternative because this would provide only
dilution of the AMD, with no source control or treatment and'
with no reduction of total metals loading into the Sacramento
River.
E.
Description of Combined Remedial Action Alternatives
The previously described components were assembled into'
combined alternatives for more detailed analysis. Nine alterna-
tives (CA-l through CA~9) underwent very detailed analysis.
Three more alternatives (CA-lO through CA-l2) underwent a less
detailed analysis. The proposal submitted by the site owner to
establish a solution mining operation at the site was screened
out in the Feasibility Study because it had not been developed to
the point where EPA could determine the technical feasibility and
economic viability of the project. In addition, the project did
not demonstrate compliance with all applicable, relevant and
appropriate federal and state requirements, and a site closure
plan had not been developed. .

-------
- 42 -
The remedial action alternatives evaluated in the Feasibility
Study and the Addendum to the Feasibility Study are:
(CA-l)
( C.a.-2 )
(CA-3)
(CA-4)
(CA-S)
(CA-6)
(CA-7)
( CA-a )
(CA-9)
Diversion of upper spring .Cre~k to Flat Cr~ek, diversion
of South Fork Spring Creek to~ock Creek,/~omplete capping
above the Richmond Orebody, groundwater interception,
and copper cementati6n. .
Diversion of upper Spring Creek to Flat Creek, diversion
of South Fork Spring Creek to Roc~ Creek, complete capping,
groundwater interception, and treatment.
Diversion of upper Spring Creek to Flat Creek, diversion
of South Fork Spring Creek to Rock Creek, and treatment.
Complete cagping, groundwater interception, and treatment.
Enlargement of SCDD, diversion of upper Spring Creek to
Flat Creek, and diversion of South Fork Spring Creek to
Rock Creek.
Enlargement of SCDD, diversion of upper Spring Creek to
Flat Creek, diversion of South Fork Spring Creek to Rock
Creek, and.copper cementation for flows from Richmond
portal, Lawson portal, and Old No.8 seep'.
Enlargement of SCDD,diversion of upper Spring Creek to
Flat Creek, diversion of South Fork Spring Creek to Rock
Creek, complete capping above Richmond orebody, ground
water interception, and copper removal from Richmond
portal, Lawson portal, and Old No.8 flows using copper
cementation.
Treatment of AMD from the 'Richmond portal, Lawson portal,
and Old No.8 seep with lime/limestone treatment, complete
capping, Upper Spring Creek diversion, South Fork Spring
Creek diversion, Upper Slickrock Creek diversion, and
enlargement of Spring Creek Debris Dam. This alternative
includes disposal of dewatered sludge from the treatment
process in Brick Flat Pit.
Filling all the major mine workings (Hornet, Richmond,
~o. 8, and Old Mine orebodies) with LDCC, partial capping,
Upper Spring Creek diversion, South Fork Spring Creek
diversion, Upper Slickrock Creek diversion, treatment of
the remaining AMD from the three major sources by lime/
limestone neutralization, and dispo~al of dewatered
treatment sludge in Brick Flat Pit, and enlargement of
Spring Creek Debris Dam.
(CA-IO) Excavation of the upper portions of the orebody, waste
rock, and tailings piles and off-site disposal in a lined

-------
- 43 -
.~ ,",." '...'', .'
:;;;"';,-.w""i":'i':::"'~";Q,,;:i;;:~1Vi.'":;;'f"l!rC'4:'l' i:,tyt7dOreme-V'(iit''';:;;CYf''''-''eont'am'i';n'a-.t;ed;r.-:sed,im e'n;ts:,;:
-------
- 44 -
The point of compliance with the water quality criteria for
alternatives CA-l through CA-9 is below Keswick Dam (the most
upstream point to which salmon can migrate).
I ~'. ..
Alternative CA-lO should achieveC\quatic wate~':quality
criteria everywhere from the ~ite proper downstream. Alterna-
tive CA-ll should achieve water quality criteria below the
proposed collection ,dams., constructed on Boulder Creek and
Slickrock Creek, but it would leave the tributaries near Iron
Mountain Mine devoid of aauatic life. Alt.ernative C.a.-12 should
achieve water quality ~riteria ~elow Spring Creek Reservoir, but
it would leave the reservoir and points upstream devoid of aquatic
life. .
F.
Alternatiye Screening.
According of the NCP, alternatives must be developed
for each of the following five categories "to the extent
that it is both possible and appropriate".
a)
. .
Alternatives for treatment or disposal at an off-site
RCRA permitted facility approved by EPA.
b)
-
Alternatives that attain applicable and relevant federal
public health or environmental standards.
c)
. .
As appropriate, alternatives that exceed applicable and
. relevent pUblic health or envirorumental standards.
d)
Alternatives that do not attain applicable or relevant
public health or environmental standards but which will
reduce the likelihood of present or future threat from
the hazardous substances. This must include an alternative
that closely approaches the level of protection provided
by the applicable or relevant standards and meets CERCLA's
objectives of adequately Drotecting public health and
welfare and the environment.
e)
A no-action alternative.
The following is a description of how each of the above combined
remedial action alternatives and the total re~oval of the. source
alternative fits into each of the five categories:
a.
Offsite disposal at a RCRA-approved facility
The only alternative that fulfilled these requirements
is C.a.-lO.

-------
- 45 -
. j-<'
~< < i--..1.. ~ 1 1 ,...u.. . .1 ~.
--'::",,,;-:,,".',":-."':, 'b;---"'Al t err na't tv'e's;~'1rl"'1;:y~.';comt"'~¥..1:ngr~W;";:\.On'.;;-=r'.~..~,;.ap.-t='=:J.:;a,a~~,,?:~";:"'~";....::..-.;;;.-.:";-:~'" :,: :";;~'.
relevant standards, guidance, and advisories
'CA-IO. For all ~acticable purposes, this is the same
alternative as tna one that ex.ceeds all applicable and
relevant and approp..rLatate standards. Due to data
limitations, it was not possible to identify what lesser
portion af th~ orebody and other sources would need to
be removed to exactly meet all standards, guidance, and
advisories. This would require mapping the fractures,
faults, and all pathways of migration through the
mineralized zone and determining the volume, quality,
and location of contaminants discharged to receiving
waters on a seasonal basis. This would involve an
extensive underground exploratory p~ogram lasting several
years at an estimated cost of about $5 million. It
should be stressed that at the start of the Remedial
Investigation (RI) in 1983, the RI/FS guidance had not
clearly delineated that alternatives be developed for
each of the five categories; there was, therefore, no
perceived need to conduct an RI of such a comprehensive
scope. .
c.
Alternatives exceeding all applicable or relevant
standards, guidance, and advisories.
CA-lO.
d.
Alternatives meeting all CERCLA goals, but not fully
complying with all applicable or relevant standards~
guidance and advisories.
Alternatives CA-2 through CA-9 and CA-ll and CA-l2.
Combined alternatives CA-5 through CA-9 vary on their
ability to meet appropriate and relevant environmental
standards based on the amount of storage provided by
the enlargement of the Spring Creek Reservoir.
e.
A no-action alternative.
The No-Action alternative was carried through the
Feasibility Study as a baseline to compare remedial'
. action alternatives. -
The combined alternatives matrix (Table 12) describes
each alternative, presents the capital and operation
costs to meet EPA standards for 1978 and the antici-
pated benefits of each alternative.

-------
Table 12
Combined Alternatives Matrix5
ALTERNATIVE
, OOST ($ Million)
Capital
O'M (Present ~rth)
ANTICIPATED BENEFIT
EPA Water CkJality Criteria (EP~)
State Basin Plan Cbjectives (SBPO)
No Action
CA-l Upper Spring Creek aM South
Fork Spring Creek diversions
canbined wi th cooplete capping
above the Richmond orebody,
groundwater interception, and
copper canentation
CA-2 Upper Spring Creek and South
~rk Spring Creek diversions,
canbined wi th cooplete capping
above the Richmond orebody
and groundwater interception
combined with treabment
80.3
CA- 3 Upper Spr ing Creek and South
Fork Spring Creek diversions
combined with treabment
69.4
CA-4 Complete capping above the
Richmond orebody and ground-
water interception combined
with treatment'
129.3
CA-5 En1arganent of Spring Creek
Debris Dam to 23,000 acre-feet,
combined wi th uppper Spring
Creek and South Fork Spr i ng
Creek diversions
37.4
, .
CA-6 Enlarganent of Spnng Creek
Debris Dam to 23,000 acre-feet,
c011b' . "'uth Fork Spring
Creek ~ersions, and
30.6
.~, -"'. .', .", - ,
-, ,~ "
No benefit; continued degradation
of water quality' ,
1
Achieves EPAWQC below Keswick ~n
for water years 1980 and 1983 and
SBPO for water year 1980 only.
(ilbes oot achiev~ EPAW:IC or SBPO
for water years 1978 or 1981.
20.82
Achieves EPAW;:C and SBPO below
Keswick Dam for all. four water
years considered. ' ,
~.
0\
20.22
Achieves EPAW;:C and s~ro below
Keswick Dam for all four water
years coosid!3red.
22.82
Ach ieves EPAWJC and SBm be low
Keswick Dam for all four water
years considered.
. '.
. .
0.62
Achieves EPAWQC and SBBa below
Keswick Dam for all four water
years considered.
l.l~
Achieves EP~ and SBm below
Keswick Dam for all four water
years considered.

-------
ALTERNATIVE
CA-7
EnlargEment of Spring Creek
Debris Dan to 18,000 acre-feet,
canbined wi th upper Spring
Creek and South Fork Sprir¥]
Creek diversions, copper
cementation, canplete capping
above the Richmond orebody,
and groundwater interception
CA-8 Treatment of Rictmond p::>rtal,
Lawson portal, and Old No. 8
wi th 1 ime/l imestone; tota 1
cappil'YJ; upper Slickrock
Creek diversion; upper Spring
Creek diversion; South Fork
Spring Creek diversion; and
enlargEment of Spring Creek
Debris Dam (if needed)
CA-9
Injection of low-density
cellular concrete into old
mine w:>rkings (Hornet, RictJooOO,
Old Mine, and Old No.8);
partial capping; upper Spring
Creek diversion; upper Slickrock
. Creek diversion; South Fork
Spring Creek diversion; and
enlargEment of Spring Creek
Debris Oem (if needed)
CA-I0 Excavation of the u~Jer portions
of the orebody, waste rock, and
tailings piles with.off.-site
disposal in a lined facility;
ranoval of contaminated sediments
in the affected tributaries and
the Spring. Creek Reservoir; and
the removal of the Minnesota
Flats tailings pile.
Table 17
.inued)
OOST ($ Million)
Capital
40.9
42.3
68.1
1,400
O&M (Present \-brth)
. 1.92
13 .02
4.12
0.03
ANTICIPATED BENEFIT
EPA Water ~lity Criteria (E:P~)
State Basin Plan Objectives (SBBa)

Achieves EP~ and SBro below
. Keswick Dam for all four wat~r
years considered.
,.;
,.
. Achieves EP~' and SBro bel<;>w
" Keswick £an for all tour water
years considered.
.,'
"
~
-.I
Achieves EP~ and SBro below
Keswick Den for allfo,ur wat~r
years considered.
. ~
'"
.i
i '.
Achieves background water qurl i ty
at all points.
;.
"

-------
ALTERNATIVE
Table 12 (Continued)
cmT ($ Million)
Capital
O&M (Present Worth)
ANTICIPATED BENEFIT .
EPA Water ()Jality Criteria (EPAW;)C)
State Basin Plan Objectives (SSP())
CA-ll
~val of the Minnesota Flats
tailif¥Js pile and sediments in
the tributaries and Spring
Creek Reservoir with off-site
disposal; collection of leachate
fran all [X)int and oon-point
sources ,and treatment of the
collected leachate with lime
neutralization. This alterna-
tive includes construction of
a nearby HeRA-type sludge
disposal facility.
3514
Achieves background water quality
at all points below the leachate
oollection impowrlnents near the
confluence of Spring Creek and
Flat Creek and Spring Creek and
Sl ickrock Creek. Flat creek' .
and Slickrock Creek will remain
contaninated upstrean of these
impowrlnents. '
r'
CA-12 Utilization of the Spring Creek
Reservoir as a collection basin
for all point and non-point
leachate sources and treaonent
of all liquids passing throUJh
the reservoir with lime
neutralization.
2634
Achieves background water quality
at all points below SpriR;) Creek
Reservoir. The reservoir and
upstream tributaries will remain
contam inated .
~
ex>
Notes:
1.
Since CA-l did not meet water quality objectives, costs were not cauputed further, and CA"'.l was effectively
screened out.
2.
Costs cauputed for achievi~ EP~ below Keswick Dam for water year 1978.
3.
Costs for CA-IO thrO\¥jh CA-l2 I¥)t canputed to same level of detail as for CA-2 thrmgh (A-9.
- ..
i '.
4. These costs inchrle both capital and OIi.M costs.
5.
Technical, environmen~al, public health and institutional considerations can be found in Table 11 for the
canponents which make up the conbinoo alternatives.

-------
- 49 -
VII,. . THE ,IRON -MOUNTAI N c' M-INE ,:~E.MEOX:.,.--:,.~..,.:-.,.,:,:::,,,: -""."
Among the remedial- action alternatives that could be imple-
mented by EPA, the total removal ~f ~he source and. sediments in
receiving waters (Alternative CA-10~~~,considered:the only remedy
for the Iron Mountain Mine site which is capable of meeting pro-
ject cleanup objectives and 'the full requirements of the Clean
Water Act (CWA). -This' alternative would effectively eliminate
discharges from Iron Mountain and restore all tributaries to
pristine condition. This alternative was,.based on total removal
of all the sources of contamination and hauling and disposing of
them in a RCRA-approved facility. This includes material from
the following four areas:
a) Remove approximately 3.5 million cubic yards of ore and
waste rock and tai~ings piles along Boulder Creek and Slickrock
Creek.
b) Remove an estimated 200,000 cubic yards of contaminated
bottom sediments in Slickrock Creek, Boulder Creek and Spring
Creek.' It was assumed that sediment in Slickrock Creek near the
Brick Flat Pit area would be removed using conventional constr~ction
equipment. For sediment removal in the other receiving waters,'
hydraul ic clearing: was assumed.

c)' Remove approximately 620,000 cubic yards of contaminated
bottom sediments in Spring Creek Reservoir.
d) Remove about 14,000 cubic yards of tailings material in the
Minnesota Flat area.
The total cost of excavating and removing the source material
and hauling it to a Class I landfill was estimated to be $1.4 .
billion.
Alternative CA-ll comes next closest to meeting all require-
ments, but water quality standards will not be met in Boulder
Creek and Slickrock Creek and not all non-point sources will
be addressed through Best Management Practices (BMP's). This
alternative is the same as the total removal alternative except
it does not include removing the orebody. It only includes
removing bottom sediments in the creeks and reservoir and th~
Minnesota Flat Tailings pile. All costs developed for this
portion of this alternative are based on the same assumptions
discussed in CA-IO. This would consist of excavating and removing
over 800,000 cubic yards of waste toa RCRA approved landfill
which is estimated to cost about $200 million.
..

-------
.--
- 50 -
This alternativewi.l,lc,collect all point and non-p.oint --
sources in Slickrock Creek and Boulder Creek; the contaminated
water would be conveyed to a lime neutralization facility for
treatment. This alternative would.also include constructing
a nearby sludge disposal site which wou19 meet RcRA.guidelines
and all other institutional requirements. The estimated cost
of treatment is $J.51 million, bringing the total cost of the
alternative'to $351 million. -
Alternative CA-12 will meet background water quality in the
Sacramento River below Keswick Dam but the applicable federal and
state standards will not be met in Boulder Creek, Slickrock
Creek, portions of Spring Creek, and in the Spring Creek Reservoir.
This alternative involves allowing all point and non-point sources
of pollution to discharge to Boulder Creek and Slickrock Creek,
and then flow into che Spring 'Creek Reservoir. Contaminated
water would then be pumped to a lime neutralization facility for
-treatment; treated water would be discharged to the Sacramento-
River. The resulting lime sludge would be disposed of in a nearby
disposal site which would meet RCRA guidelines and other
institutional requirements. Water quality standards should be
met in Flat Creek since the only source of pollution, Minnesota-
Flats Tailings pile will be removed under this alternative~ Als6,
non-point sources ~ill not be treated with BMP's. -
Under CA-I, water quality standards would not be met in-
either the immediate receiving waters or in the Sacramento River
below Keswick Dam for several of the case years evaluated. CA-2
through CA-9 would improve water quality to varying degrees in
immediate receiving waters, although not to the point where
state water quality standards will be met; these objectives
will, however, be met in the Sacramento River below Keswick Dam.
With the exception of CA-9, these alternatives will not address
discharges from non-point sources.
VIII.
FUND BALANCING
Under 40 CFR S300.68(i)(1), the appropriate extent of remedy
must be the cost-effective remedial alternative that effectively
mitigates and minimizes threats to and provides adequate protection
of public health and welfare and the environment. In addition,
the reme4Y must be that which attains or exceeds applicable Or
relevant and apropriatc Federal public health and environmental
requirements that have been identif.ied for the site. However,
under S300.68(i)(5) (ii), EPA may select an alternative that does
not meet applicable or relevant and appropriate Federal public
health or environmental r.equirements when the need for protection
of public health and welfare and the environment at the facility
for all of the alternatives that attain or exceed applicable or
relevant and appropriate Federal requirements is outweighted by
the need for action at other sites that may present a threat to
public health or welfare or the environment, considering the

-------
- 51 -
'J,. ..' ..
. : \" . ",f" ~: . ;, .
, . . "
.. '
,
amount of moneyav'a;ilab:le, ,in: the.,Ha.~p.,t:do..u,$..-S.ub,s.tanc...e- Response",.. -. -'
Trust Fund. In the event of Fund-balancing, EPA must select the
alternative which most closely approaches the level of protection
provided by applicable or relevan; and appropria~e ,2ederal
requirements, considering the specitic.F:und-balane.edsuIt1 of money
available for the facility.

The estimate~ cost to implement the remedy (CA-10) that w~uld
meet applicable or relevant and appropriate Federal environmental
and public hea1thstandards for the Iron Mountain Mine site is
estimated to be $1.4 billion. EPA evaluated the funds remaining
under the current Superfund authorization and subsequent interim
fundings. In our analysis, we have considered that increased
funding may become available if the pending Superfund reauthoriza-
tion is enacted.
At this time, Iunds under the current Superfund authori-
zation and the subsequent interim funding are nearly depleted;
funding that remains is committed solely to, keep ongoing remedial
planning activities on an active status. Therefore, these remain-
ing funds are not only unavailable to Iron Mountain Mine but,
even if available, would not be adequate to implement an operable
unit or final remedy at the site.
The Superfund'reauthorization, if enacted, may provide,
funding in an amount ranging from $5.4 billion to about $8.5-
,billion in order to respond to 88,8 proposed and final NPL sites
over a five year period ($1.7 billion annually). Committing
$1.4 billion, or 16 to 26 percent of the potentially reauthorized
amount, to the cleanup of Iron Mountain Mine would effectively
consume at least the equivalent of one year's worth of funding.
This would be at the expense of re~edial response action at NPL
sites, expenditures for emergency response action, and other
program needs. This would severely limit the capability of the
'Agency to take timely and effective cleanup action where needed
to protect public health and welfare and the enviro~ent. The
full impact of commiting these funds solely to Iron Mountain
Mine would be to deny funding for site cleanup at between 140
and 470 NPL sites (assuming that the typical cost of Remedial
Design and Remedial Action for an NPL site ranges from $3
million - $10 million).
As ,previously mentioned, Alternative CA-ll at a cost of
$351 million is the alternative that most closely approaches but
does not achieve the requirements of the CWA. This alternative
would ut il ize Boulder Creek and' Sl ickrock Creek to capture all
point and non-point sources of pollution; contaminated water
would then be pumped from each of the two creeks to a lime
neutralization facility for treatment. Alternative CA-ll
is expected to further degrade water quality beyond current
conditions in these receiving waters. The reason is that, at
present, discharges of AMD from the three majot: sources of

-------
- 52 -
pollution are receiving copper 'cementationHt'reatmen.t,"prior . to:.
discharge to receiving waters. Nevertheless, water quality in
Spring Creek, Spring Creek Reservoir, and Keswick Reservoir would
improve substantially to the point. where certain b~fleficial uses
may return on a year round and/or seasonal basis. "Water quality
below Keswick Dam would improve beyond that required to
protect fish in th~ Sacramento River. Committing funds for this
alternative' would be 'at the expense of funding cleanup actions at
between 35 and 117 NPL sites.
Alternative CA-12 would further degrade water quality in
Boulder Creek, Slickrock Creek, portions of Spring Creek and in
Spring Creek Reservoir because AMD from the three major sources
of pollution will not receive copper cementation treatment prior
to discharge to receiving waters. Contaminated water would be
pumped from Spring ~reek Reservoir to a lime neutralization
facility for treatment and then discharged to the Sacramento
River. However, water quality in Keswick Reservoir and below
Keswick Dam would improve substantially; water quality below
Keswick Dam would be essentially the same as that in the Sacramento
River above the confluence where discharges from Iron Mountain
Mine enter the river. The level of cleanup provided by this
alternative is higher than that needed to protect aquatic life
in the Sacramento River below Keswick Dam. Funding this alter--
native would preclude BPA from taking cleanup action at between
26 and 87 sites on the NPL.
After considering these fund-balancing issues, CA-9 ($72.2
million) is the alternative that most closely approaches the
requirements of all applicable or relevant and appropriate federal
and state requirements, yet it also balances the n~ed to conserve
monies in the Fund. Funding this remedy would have a less sign-
ificant impact on EPA's ability to use the fund at other sites,
yet it would also provide significant protection at the IMM site.
Alternative CA-9 will meet Federal Water Quality Standards for
aquatic life below Keswick Dam for all water years considered;
the State Basin Plan standards'should be met for other than the
'worst case' condition. Meeting these criteria and standards
should protect the salmon population in the Sacramento River
below Keswick Dam. In addition, implementation of Alternative
C.!~-9 shol.lld greatly improve \/later qual i ty in the tributary streams
between~ron Mountain and the Sacramento River. The basis for
identifying CA-9 as the Fund-balanced remedy is discussed in
more detail in Chapter IX.
IX.
SUMMARY EVALUATION OF ALTERNATIVES
With the exception of CA-l, each combined alternative
will meet the two project cleanup objectives for each of the
case years for which they were analyz~d. Alternative CA-l
will not meet EPA standards for 1978 and 1981 conditions or
State Basin Plan objectives for the years 1978, 1981, and 1983~

-------
- 53 -
'", . ,.' .
. '
'lo.
.~ ~. .' .'
'A ~" "Feature9""4nd'"."eo'S.t's..'af.~.eom~~ne.<:hReme.dri::a':h~*1st.~n~~&,ro:-o::.~~".;'r'~'~~'...:Z..~.:
Alternative CA-l does not meet either EPA or State water
quality objectives and is not considered an appro~~iate
remed ial action al ternati'le for s i t'e cleanup because. releases
from the site would continu~,to present acute and chronic
impacts on aquatic life.

A~ternatives CA-2, CA-3, and CA-4 will meet both EPA and
State water quality objectives through various combinations of
source control, lime/limestone neutralization treatment, and
water management alternatives at costs ranging from $89.6 million
to $151.1 million. These alternatives differ in the number of
AMD sources that will receive treatment.
Alte~natives QA-5, CA-6 and CA-7 will also meet both
project cleanup objectives at a cost substantially below
those projected for Alternatives CA-2 through CA-4. These
alternatives differ most notably in the increased storage
capacity of the Spring Creek Reservoir provided by the enlarge-
ment ~f Spring Creek Debris Dam. Alternative CA-5 will meet
cleanup objectives by relying exclusively on wate~ management.
measures to ensure that adequate dilution water is available "
to meet project cleanup objectives below Keswick Dam. Under
this alternative, no source control or treatment remedies
would be implemented. Alternative CA-6 is similar to Alterna-
tive CA-5 except that this alternative would utilize copper
cementation treatment of 'controlled' AMD flows at a lower
cost to meet EPA cleanup objectives and slightly higher cost
to meet State cleanup objectives. Alternative CA-7 relies
upon source control, treatment, and water management remedies
to meet EPA and State cleanup objectives at a higher cost
than both Alternatives CA-S and CA-6 but considerably lower
than Alternatives CA-2 through CA-4.
Alternatives CA-8 and CA-9 meet project cleanup objectives
through a variety of source control, treatment, and water
management remedies. These alternativds are very similar
and differ only in the extent of capping that would be
required over the Richmond orebody, and the volume of AMD
receiving lime/limestone neutralization treatment. CA-9
also includes the injection of low-density cellular concrete;
this is' not a component remedy of CA-8. CA-8 will meet
federal and state objectives at costs ranging from $55.3 '
Ittillion - $62.7 million; CA-3 will 1\eet the same objectives
at a cost of $72.1 million to $85.1 million. Although the
'cost of CA-9 may be higher, the actual cost of CA-9 may be
less fo~ several reasons: a) further studies may indicate
that the underground mine workings do not need to be completely
filled with LDCC; 2) if waste rock at Big Seep can be used in
,the formation of LDCC, the Upper Slickrock Creek diversion
($790,000) could possibly be eliminated; and 3) if LDCC is

-------
- 54 -
... . ,- --- ",".;-_n
'. -'-:fuTlyc"succ'essful,~' 'it' would- precli:1de:-:l:had1_ee.d:,::to,:.:_c.()Qs-tt'uct:~a"
lime neutralization facility, which has an estimated capital
cost of about $8 million. More important, however, CA-9
is an approach that aggresively moves~ to stop AMD formation.
Under other al ternatives, for ins tance, . AMD may con'tinue to
be formed, and thus require treatment, for hundreds of years.
....
8.
Evaluation of Combined Remedial Alternatives
CA-2 through CA-4 will meet primary ~nd secondary cleanup
objectives and the goals of the NCP at a relatively high cost
when compared to the other alternatives. CA-2 and CA-3 treat
the five major sources of pollution plus all other sources
discharging in Slickrock Creek through lime neutralization~
CA-4 addresses these same sources in aqdition to treating all
other sources in 80~lder Creek. ' These alternatives will be
generating tremendous volumes of lime sludge each year which, on
a periodic basis will continue to require the identification and'
development of new off-site disposal areas. Treatment of AMD '
and off-site disposal will be required for a period of time
far exqeeding the 30-year project period, and perhaps be needed
in perpetuity. This, in effect, significantly increases the -
State's commitment to operate and maintain the lime neutralization
facilities, and will require that nearby undeveloped land be
committed for land disposal for as long as Iron Mountain Mine
continues to discharge AMD. The need for long-term treatment
tends to make these alternatives less reliable. These alter-
natives would reduce the metals loading to receiving waters and
meet Federal and State standards, but for the added cost, would
not result in a further improvement in Water Quality at the
point of compliance. For the above reasons, CA-2 through CA-4
are not considered cost-effective remedies for the Iron Mountain
Mine problem. '
CA-5 will meet both EPA and State water quality objectives
at the point of compliance (primary objective) at a relatively
10w cost, but will not meet a principal goal of the NCP or
the secondary cleanup objective. The reason for this is
that CA-5 does not address the problem at its source or
minimize the migration of hazardous substances, pollutants or
contaminants because it relies exclusively upon the dilution
of these pollutants to meet primary cleanup objectives. For-
these r~asons, this alternative was not considered to be an
appropriate remedy for Iron Mountain Mine. .
CA-6 utilizes copper cementation treatment, and like
CA-S, relies on dilution to meet primary cleanup objectives.
For the same reasons as discussed under CA-S, and in considera-
tion of the fact that copper cementation will not meet the
BAT requirements of the CWA, this alternative was not considered
an appropriate CERCLA response to the Iron Mountain Mine problem.
....

-------
- 55 -
('" " ...1" '~'o: "'1" 'It
..' ~',- ~t , ,..;.~,> ,".-1\'
."c'.,,!.: - cr" 'When- compared:"~-~5:~~-d~,-CA~It.ha.l:te.r~...;GA.-....7...~u:w:i.das,;;.a,n;.,,,.~":~':-.:4-~..
improved balance of source control, treatment and water management
components to meet primary and secondary cleanup objectives at
a slightly higher cost. CA-7 alsa utilizes copper:; ..cementation
treatment and, thus, will not meet Best.Available'Technology,
as specified by the CWA. CA~7. will result in a reduction of
pounds per day of heavy metals entering the Sacramento River
through implementation 'of source control and treatment alterna-
tives, but to a lesser extent when compared to other source
control and lime neutralization treatment. Alternatives. This is
because the copper cementation process does not remove cadmium or
zinc from the AMD. Therefore, while CA-7 will meet the primary
cleanup objective, it will only partially fulf~ll the secondary
objective. Also, CA-7 will do very little to improve overall
water quality in immediate receiving waters. For these reasons,
CA-7 was not considered an appropriate remedy for Iron Mountain
Mine.
CA-8 and CA-9 are very similar as previously noted and will,
therefore, be evaluated together. Both of these alternatives
provide a good balance of source control, treatment and water
management. By utilizing lime neutralization treatment of the,
three major sources, both CA-8 and CA-9 will satisfy the BAT'
requirement of the:CWA. This, combined with capping (and in the
case of CA-9 the use of LDCC) will result in substantial water
quality improvement in the immediate receiving waters and wi'll,
therefore, reduce the amount of heavy metals discharged to the
Sacramento River. For approximately 6-8 months of the year, from
about lata-Spring to early-Fall, there should be no discharges of
AMD to receiving waters. During these periods, it is anticipated
that there will be a return of certain beneficial uses to Keswick
Reservoir and possibly a return of other beneficial uses to
portions of Spring Creek. .

In the case of CA-9, lime neutralization treatment may not
be needed if the injection of LDCC is successful in preventing or
reducing the formation of AMD. Even if LDCC is not fully success-
ful, the volume of AMD that would need to be treated is thought
to be much less than under CA-8. Therefore, Brick Flat Pit will
have a sustained storage life for lime sludge beyond the 30-year
period calculated for CA-8. This ~eans that off-site disposal
can be postponed to a later date and the rate of developing new
off-site disposal sites under CA-9 will be slower when compared
to CA-8. CA-9 will also utilize waste rock and tailings.piles
and treated ~~D from the three major sources when formulating the
LDCC. This brings CA-9 an additional step forward in meeting
the require~ent of the CWA by addressing non-point sources;
these sources will not be addressed by CA-l through CA-8.

-------
- 56 -
. ~, .' . .".,'
." . ,-. ,... ,",. .. . . . ""
The mes t a't tact ive Eea t ure 6fCA- 9 ~ however, is the use: of
LDCC. If fully successful, this alternative could prevent or
significantly reduce AMD to a point where treatment may not be
cequired. This, of course, wouldne'an that thece :~o.uld no longer
be a need to utilize Arick Flat Pit as a'storage basiri or a need
to identify ~nd deve10p new off-site li~e sludqe disposal sites.
It is this aspect pf CA-9 that makes it a superior choice over
the other combined r~medial action alternatives.
x.
fDENTIFICATION Of FUN~-8ALANCED REMEDY AND REMEDY SELECTION
STAATF:GY
Alternative CA-9' is t~e appropriate Fund-balanced remedy
for' Iron Mou'ntain ~1the. Alt~rnative CA-8 is EPA's next preferred
alternative. These two alternatives differ principally in the
use of LDCC, in the volume of ~MD to receive lime/limestone
neut~alizatfon t~eatment, and whether a partial cap (CA-9) or
complete cap (CA-8) is constructed.*
Full implementation of alternative CA-9 is expected to
significantly improve water quality in the Iron Mountain Mine
area. Table 13 presents the anticipated water quality benefits-
that should result from CA-9. Water quality in Keswick Reservior
and the Sacramento River would also see similar water quality
improvements. Removing the Minnesota Flats Tailings pile, the only
known source to irnp~ct Flat Creek, would result in immediate
improvements in water quality and, over time, ~ay cause a return
of all beneficial uses to this water course. .
Reducinq the metals loading to receiving waters would also
~ean that there are fewer heavy metals in solution~ fish in the
Sacramento River have been shown to bioaccurnulate these metals.
If it were possible that bioaccumulation, which h~s been demon-
strated in fish tissue, was also causing a potential human health
problem, we anticipate that this impact would be eliminated or
reouced by the remedial action ~rogram. .
. ~lso, installation of perimeter control (i.e., fencing,
posting warning signs) should minimize potential public health
impacts ftssociated wit~ coming into contact with AMD or~MD-laden
waters.
The selected alternative for this operable ,unit consists
of the source control and water management compon~nts that are
common to both CA-8 and CA-9. The Agency is not now prepared
to ~ake a final decision'on whether to proceed with the source
control measure of injecting low-density cellular concrete into
the underground mine workings or'straight lime/limestone neutrali-
zation treatment of AMD. To assist in making this decision,
'"

-------
Table 13.
Anticipated water Quality Improvements with CA-9
Current Water Quality (mg/l)
CA-9
RECEIVI~ W1\TER OOPPER ZINC ~IUM IiI
    2.1-
OOULOCR CREEK 4.25 25.0 0.11 3.3
    3.5-
SLICKROCK CREEK 2.56 0.99 0.012 4.1
    3.0-
SPRI~ CRE~K 1.2 4.7 0.03, 3.4
OOPPER ZINC CADUUM ~i
   2.7-
1.20 6.1 0.03 4.0
   , .
 1/  4.7-
0.15 0.06 . 0.001 5'.5
   3.4-
0.47 2.1 0.01 4.5
   ,
,
V1
-J
.'P;
. "

-------
- 58 -
this ROD authorizes EPA- to conduct a- hydroge-ol-ogic--inves"tig-ation,
and LDCC pilot and nemonstratio~ testing to deter~ine a) if the
site is conducive to the ~pplication of LDCCi b) the proper
formulation of LDCC needed to withsta~d AMD corro~ioni and c) if
LDCC is technically feasible, reliable).and can b~'~uccessfully
imple~ented at Ir0~ Mou~tai~" MIne. If these studies conclude
that LDCC is tech~ically feasible and can be implemented, EPA
'.-lill prepare a second Record of Decision (ROD) documenting the
selection of the source control measure.
Alternatively, if the site is not conducive to the applica-
tion of LDCC or if LDCC is judged to be technically infeasible,
a second ROD will be prepared to select the components of CA-8
(co~plete cappinq of the Pichmond orebody and lime/limestone
treatnent) that hav!not bee~ selected by this ROD.

* Construction of a partial or complete cap over the
Ric~ond ore body is consistent with EPA's current
view of Iron Mountain as a waste source. A cap will
reduce infiltration of precipitation and thus reduce
the volume of acid ~ine ctrainage that is formed.
However, the ore body could be considered a resource,
suitable for exploitation by a solution mining process
(as currently" proposed by the potentially responsible
parties). Placing a full or partial cap over the ore
body could be ~ hindrance to efforts to implement a
solution mining process. Therefore, EPA will not begin
implementation of -the capping component for a grace
period, while th~ possibility of developing the ore
body as a resource is considered further. Commercial
development of the ore body would have to include acid
mine drainage discharge control measures and other
environmental safeguards. A final decision r.~garding
the capping component will be made following che
grace pee iod.
XI.
SU~MARY OF RECOMMENDED OPERABL~ UNIT
The recommended operable unit consists of:
o - .Approximately 2.5 acres of cracked and caved ground'
areas above the Richmond orebody will be capped using a
soil cement mixture or othec suitable matecial. The"
areas will be gcaded and benched and covece~ with the soil
cement mixture. Interception ditches will be used to
divert clean surface water runoff from the ocebody.
o Up to 800 cubic feet per second (cfs) of clean surface
water will be diverted from the Upper Sprinq Creek
watershed befoce it reaches that portion of the basin
af.fected by Iron Mountain Mine. This will be accomplished
by constructing a low diversion dam and an a-foot tunnel.

-------
- 59 -
, '
, ,
. : ~
. . . ~
th r oug h-', t he~.' iN dg:e~.tlha!b ~.e,pa;L:a.t:e$;,d:ha:h~;ltJ.Ag,-£r,e,ak,.~,';'."-,. ",
Flat Creek watersheds. A chute and energy dissi~ators
will be needed to com~lete the conveyance of flows from
S~ring Creek to Flat Creek.,
"\',";..'
,; ~ ... .:..
, .
o Up to 250 cfs of clean. water will be diverted from
the South Fork of S~rln~ Creek across the drainage
divide' into Rock C~eek which discharges to the Sacramento
River below Keswick Dam. The ~urpose of this alternative
is similar to the Upper Spring Creek diversion and will
require a small diversion dam and 4,000 feet of ~ipeline
to complete the conveyance of flows to Rock Creek.
o Clean water fro~ Up~er Slickrock Creek will be diverted
around the waste rock and slide debris, which contribute to
releases frorn a.ig Seep, to the lower reach of Slickrock
Creek.
o Spring Creek Debris Dam will be enlarged from its present
storage capacity of 5,800 acre feet to 9,000 acre feet.
o' Installation of Perimeter controls as necessary to minimize
any direct contact threats.
o Perform hydrogeologic study and field-scale ~ilot
demonstration to better define the feasibility of utilizing
LDCC to minimize AMD formation.
XII.
RECOMMENDED CLEANUP OBJECTIVES AND DESIGN YEAR
, Designing a cleanup program to meet EPA Water Quality
Criteria for Protection of Aquatic Life for the 'worst case'
c~ndition (1978) was judged to be appropriate because it is under
conditions similar to 1978 that the greatest impacts on aquatic
,life would be felt. It should be noted that the so-called
"worst case" year is based on very few years of data. Also,
water quality model ~uns predicted that, targeting a cleanup
program to meet EPA water quality criteria for the 1978 runoff
conditions (wet year following a drought) would ensure that more
stringent State criteria for the other three cleanup case years
would be met.' Stated differently, t~e EPA program should meet
State criteria for every year except the worst case year, at
which time the federal standards will be met. Under these,
conditions, ~eeti~g federal standards should prevent fish kills
from occurrJng in the Sacra'1\ento River.
XI I Ie
CONSISTENCY WITH OTHER ENVIRONMENTAL LAWS
According to the NCP, 40 CFR Part 300.68 (i)(l), remedial
actions must attain or exceed applicable or relevant and appro-
~riate Federal public health and environmental requirements
~

-------
- 60 -
. ,", .....'n ;.~ .-
.. . --- ."."." .
_.uQless.oneof.the.excep~ions~of_Section.,300.69(i)(5) applies.-. .
." "One'of"'these exceptions is ~l1nd-balancing. This I'rovision allows
EPA to select the alternative which most closely approaches
the level of protection provided ~y applicable or ~elevant and
appr::>priate requirements by considering the arT1ount.of money
remaining in the Trust ~un9 ~n~ the heed to take actio~ at other
NPL sites.
The selected overall remedy (C~-9) is presented for the
discussion of the consistency with other ~nvironmental laws even
though the current ROD is for the first operable unit only. The
selected remedy would fill the major mine workings with low-density
cellular concrete to greatly reduce ~MD production: partially cap
Iron Mountain to reduce the infiltration of clean water into the
ore body: divert clean surface waters away from tailings piles
and contaminated areas; if necessary, treat the (reduced) flow
of A~D from the major point sources by lime neutralization; and.
enlarge Spring Creek Debris Dam to provide flow equalization.
In order to reduce infiltration of clean water into the ~ountain,
some grading and filling of depressions is antidipated in addition
to the,partial cap. In particular, an open pit called the Brick
Flat Pit is to he filled to prevent accumulation of water.'
Dewatered sludqes fro~ the lime neutralization process, as well
as the tailings from the Minnesota Flats Tailings piles, will be
pl~ced in the Brick ~lat Pit. The selected remedy does not:
address all waste rock dumps or tailings piles along Boulder
Creek and Slickrock Creek; collect and treat all seeps or sub-
surface drainag~ along Boulder Creek and Slickrock Creek; address
metal-bearing sedi['T1ent~ in receiving waters: or fully achieve
aquatic water quality standards in Boulder Creek, Slickrock Creek,
~ortions of Spring Creek, and Keswick Reservior. In essence,
the selected remedy will achieve aquatic water quality standards
below Keswick DaM, but not in the tributary streams: however,
water quality in these receiving waters is expected to improve
substantially to the point where certain beneficial uses may
return on a seasonal basis.
The major environmental ~tatutes that shoulrt be addressed
with regard t~ this site include the Resource Conservation and'
Recovery Act (RCRA), the Clean Water Act (CWA), the National
Envirol1I"lental Protect ion Act (NEPA), and the Endangered Spec ies
Act (ESA). In addition, the selected alternative's consistency
with a number of other ~ederal and State regulations is discussed
in the ~easibility Study anrt its Addendum.
RCRA
. The partial capping of the mountain and the filling of
Brick ~lat Pit with tailinqs from the Minnesota ~lats area a~
well as disposing of dewatered lime sludges are two components
of the selected remedial action that are of interest here. Iron
Mountain Mine is an inactive mining site, and the solid materials
.'

-------
- 61 -
~, . . .
. .
-., .'..-: ...~.:: .
'foLirid at':: .the; s i'te: -a'rp.-~ cO'As1:de'!ieQ,.,{'m\i:n,-i-~,,,,waS>t-es'r ~,tb~"":;RC~~,4s,,,"1"f11"~'~';'1..;,.;,.''':;'''':':
not generally applicable or relevant or appropriate. However,
portions of the RCRA Subtitle C requirement ~ay be relevant and
aporopriate for some aspects of the remedy. We co~sidered the
RC~A Subt i tIe C requ ir~men ts in for!T141a.t.ing var iouS" 'as f.)ects of
the alternative re~edial actions. In addition, Subtitle D require-
ments may be appropri~te at the site. In particular, qrading
anct capping' to reduce infilt~ation of rain waters into tailings
piles (or the ore body) seems appropriate. The partial cap is
intended to be pldced over badly fractured areas and areas of
relatively low slope. A soil/cement mixture appears to be the
most cost-effective approach to reducing infiltration into the
ore body: The multi-layered clay cap does not appear to be
necessary for this application. Also, because of the steepness
of some of the slopes, complete capping of the mountain is not
technically feasibl&.or practical.
With regard to the disposal of sludges generated by the lime
neutralization process, it may be most protective to place the
sludges (after dewatering) in a double-lined facility. Such a
facili~y would have to be located off-site, because there are no
areas suitable for such a facility on-site.' However, the selected
remedy is to place these sludges in Brick Flat Pit on top of Iron
Mountain. This is :considered a more appropriate approach for
several reason,s: ( I) the pi t needs to be filled in order to .
prevent water from ponding in it, (2) the metals contained in
the dewatered sludge are relatively immobile and hence should be
safe to place in an unlined pit, (3) should the metals migrate,
they would reenter the ore body and eventually be recaptured by
the AMD treatment system, and (4) the pit provides the probable
least-cost disposal option. It is estimated that Brick Flat Pit
could provide 30-plus years of disposal capacity, depending on
~ludge generation rates. (If t,he LDCC is fully successful in
stoppingM1D formation, then no treatment would be required, and
no sludges would be generated.)

Placement of the tailings from the Minnesota Flats area
in Brick Flat Pit is also selected. The tailings came from an
ore roasting operation near Iro~ Mountain, and theY'contribute
approximately one percent of thA total metals discharge from the
site via surface water runoff. Removal of the tailings from
their present location would allow Flat Creek to be restored~
Placemerit of. these materials in Brick Flat Pit is somewhat
analogous to placing materials that have migrated off-site from
a landfill back on the landfill prior to capping. The metals
concentrations are less that. those of the underlying ore body,
and the volume is significantly less than that of the ore body.
CWA
Section 301 of the Federal Clean Water ~ct requires that
any point source. discharge to waters of the United States

-------
- 62 -
.:.c~.._..Jn..e.~r...t:e~hn.ology.:-.b.ase_d. ..e.E.fl.uj!n.t. _lJ./tti. t.at i.ons (Bes t Pract icable
Technology Currently Available (8PT) by July 1, 1977~' a~d
Best Available Technology Economically Achievable (BAT) by
. July 1, 1984) as well as effluent limitations necessary for
achieving compliance with water qt.ial(~{' standards,i.:'by July 1,
1977. All Clean Water Act requirements' may be met by preventing
discharge. Waters of the U~ited States in the Iron Mountain Mine
area include Boulqer Creek, Flat Creek, Slickrock Creek, Sprinq
Creek, Keswick Reservoir, and the Sacramento River.
EPA has determined by Best Professional Judgement that
the effluent limitations for ~ine drainage at 40 CFR Part 400,
Subpart J, which are achievable by using lime treatment and
precipitation, meet the BPT/BAT/BCT requirements of the CWA for
point source discharges at this site.

Water quality'standards established pursuant to the CWA are
currently applicable to the Sacramento River.and tributaries
above Hamilton City. These standards were adopted by the Central
Valley Regional Water Quality Control Board on April 27, 1984,
and were approved by the State Water Resources Control Board and
EPA. These standards limit dissolved concentrations of cadmium
(0.00022 mg/l), copper (0.0056 mg/l), and zinc (0.016 mg/l). .
Other applicable water quality standards include a pH range of
6.Sto 8.3, with ~. maximum deviation of 0.3 units from ambient -
conditions, as well as. freedom from color, turbidity, settleable
material, sediment, toxicity, and suspended materials in amounts
that adversely affect beneficial uses. Water quality standards
are ~urrently violated at all times for each of these water bodies
except for the S~cramento River below Keswick Dam.
While substantial wa~er quality improvement above current
conditions is expected through implementation of Alternative
CA-9, State and Federal standards will probably not be met in
portions of Spring Creek, Slickrock Creek, 80ulder Creek, and
Keswick Reservoir at any time. Alternative CA-9 achieves water
quality at a point helow Keswick Da~. As described under Fund
Balancing, the cost of meeting water quality objectives in the
str~~m near the source is extremely large and fund balancing is
used to back off to a less costly re~edy.
NEPA
Under NEPA, an Environ~ental Impact Statement (EIS) must be
prepared for Federally-funded projects. The environmental
analysis included in tl1e Feasibility Study is normally considered
to be the functional equivalent of theEIS. However, in this
c~se, the environ~ental impact of the proposed stream diversions
are beyond the scope of the Feasibility Study. Therefore, prior
to final design anct construction of water diversion components
.,

-------
- 63 -
.0 r changes. i oc.t.be <:r-est o-r;..p(!)"ol.:.e:he:.va:t-J:'.o{'''s":-of",~t-Be:-;.!S pr ing.: .0r.eek-. .. .:;:.:_;:~ -.'
Debris Dam, the Bureau of Reclamation, under an aqreement with
EPA, will conduct any necessary supplemental environmental
assessments..
:It ".
. . .
ENDANGERED SPECIES ACT Of 1973
The winter run of salmon are being. considered by the National
Marine Fisheries Service for protection u~der the Endangered
Species Act. Therefore, if the Service takes final action to
protect the winter run of. sal~on, this legislation would be
applicable to the cleanup of Iron Mountain Mine since the site
is the main ~ource of pollution that places the salmon at risk.
The operable unit and final remedy Eor Iron Mountain Mine will
ach ieve water qual q~y standards in the Sacrarnen to River below
Keswick Darn, the major spawning area for the salmon. In taking
remedial action at Iron Mountain Mine, EPA will be in compliance
with the intent of the Endangered Species Act.
XIV.
OPERATION AND MAINTENANCE
-~ .
Capping of Cracked and Caved Ground Areas
. Ma in tenance w.i 11 be requ ired for the ditches, benches, and
soil-cement cap. The ditches will require periodic maintenance
consisting of the removal of debris and repair of cracked
sections. Benches will need periodic removal of depris.
. B.
Water Management Alternatives
Expected operation and maintenance requirements are minimal
for these alternatives. There are no mechanical or electrical
system components to maintain anrl no process to monitor or manage.
It is possible after an extre~e runoff event that some repair of
channel erosion damage could be required. Sediment accumulation
.could ~e a problem at so~e point in the system, although proper
design considerations should reduce any associatert maintenance
problem~ to a minimumi . .
xv..
COMMUNITY RELATIO~S
Documents made available for public review and comment
included the Remedial Investigation (RI) and feasibility
Study (FS) reports and the ~ddendum to the FS.
.
The RI was made available for review and comment in
February 1985, and again on August 2 through August 23, 1935.
The public comment period for the FS was held between August 2
and August 23, 1985. Public notification of the public
..

-------
- 64 -
" .
-- -. ..', .. ~ .. ,
;:.', cOf"lmentper iod ,was: announced' tW0'; wee-kg.,i.~t~'Or"n-tCr,t'he "p'uM l'e: ,';, '''-, -
comment period through notices in local newspapers. A Fact
Sheet summarizing the contents of the RI and FS reports was
sent to the mailing list during the week of July 22, 1985.
A public meeting was held on August' 15; ,1985 in Redding, CA.
The m~jorityof comm~nts received at the public meetinq
were from H1MI and Stauffer. These parties stated their
objections to the -implementation of the EPA cleanup program,
and voiced strong support for allowing IMMI to proceed with
its ~oncept for an in situ leaching and metals recovery
project. .
Written comments were received from the PRP's, state agencies,
one resident along Flat Creek, and sportsfishing' and recreational
organizations. In general, the PRP's and their consultants
supported the IMMI 'proposal, stated opposition to an EPA funded
cleanup action, and called into auestion the credibility of the,
FS. State agencies and other organizations lent support for an
EPA funded remedial action and raised concerns about proceeding
wi th the IMMI .proposal. Responses to the comments are presented
in the,attached Responsiveness Summary.
A fact sheet summarizing the results of the Addendum to the
FS was sent to the:mailing list on July 14, 1986. The public
comment period for the Addendum was held from July 25 through
August 15, 1986. Public notification of the public comment'
period was announced about three weeks prior to the public comment
period through notices in local newspapers.
Written comments were received by the PRP's, federal and
State regulatory agencies, two landowners near the site, consultants
associated with IMMI, and 33 citizens who siqned petitions and/or
form letters supportinq the IMMI proposal, and 5 letters from
residents in the Redding area.
As a general statement, com~ents from the PRP's and consult-
ants for IMMI stated firm support tor the IMMI proposal and
opposition to the EPA proposed cleanup program. There was a
concern that injecting t~e LDCC into the underground mine wor~ings
would interfere with the IMMI proposal and would also destroy a
valuable mineral resource. The PRP's voiced stronq opposition
to proceeding with LDCC because it is an unproven technology' for
the purposes for which it would be applied at Iron Mountain
Mine. The PRP's stated that the technology was not technically
feasible~ Stauffer indicated that, for this reason, the approach
was not consistent with the NCP because 'it was not an established
technoloqy. The PRP's also stated that the IMMI proposal was a
far superior alternative and that IMMI had secured funding to
finance its commercial mining venture ~nd an environmental
control program. Stauffer asserted its view that Region IX had
incorrectly interpreted the Clean Water Act in applying BAT for
control of AMD from "abandoned mines"~ that water quality
compliance criteria must be negotiated on acase-by-case basisJ

-------
- 65 -
,it .'
i 'a nd that,.;.the.' .po i-nt.:: o.i....compil ariGe.,J.o:r.;'J:T\eeting,..'c'l,e.a.!;\~p_,,~,e_~t.iy',e.s......<
should continue to be met below Keswick Dam. Stauffer also
protested that the three week public review and comment period
was inadequate and inconsistent with CERCLA and the community
relations provisions of the NCP beca'use.. .the Adden&um.represented
a sharp departure from the original FS and that important and
complex technical issues were raised by the FS Addendum.
"" '. ';'. .~.;
The petition and form letters state
-------
. ",-,-.....,
"XVI".
- 66 -
. SCHEDULE-'
, "
., ,
o
Approve Remedial Action:
Sign Pecord of Oecision
"
Week of September 22,
1986
;:'~ .. .:. .
Pre-Desiqn for all source control
and trea tmen t '~'omponen ts
Hydrogeologic investigation and
LDCC pilot an,j demonstration test
Remedial Design
a)
b)
c)
Partial capping
Upper Slickrock Creek diversion
South Fort Spring Creek
diversion: and
Upper Spring Creek diversion
.. .
o
:ommence Pemed ia 1 Des iqn '
and Re~edial ActiQn of
Wat~r~1anaqell'rerlt ~ltp.r-'
natives
Funding Pending
Reauthorization of
C ER LC A
nnce CERCLA has been reauthorized, the RD/RA phase for Iron
Mountain Mine is proposed to be implemented in the following
manner:
L
2.
3.
4 .
5.
6.
7 .
d)
Remedial Action
a)
b)
c)
Partial capping
Upper Slickrock Creek diversion
South Fort Spring Creek
diversion: and
Upper Spring Creek diversion
d)
Remedial Design:
LDCC (if feasible)
a)
b)
Richmond
Sl imrock
Remedial Action:
LDCC
a)
b)
Richmond
Slimrock
RD/~~: Lime ~eutral ization
(if needed)
FY 1987, 1st QTR
FY 1987, 1st QTR
FY 1987, 3rd QTR
FY 1987, 4th QTR
FY 19A8, 1st QTR
FY 19R8, 3rd QTR
FY 1988, 3rd QTR
FY 1989, 3rd QTR
PY 1990, 2nd QTR
FY 1991, Ist-QTR
FY 1991, 3rd QTR
will be determined
by results of LDCC
pilot and demonstra-
tion tests.
.'

-------
- 67 -
XVII.
FUTURE ACTIONS
, . .-
After this Record of ~cisio~ ts~igned, EPA!will enter
into an Interaqency Aqreemen~ with the u.S. Bureau of Reclamation
(Bureau) for the design and construction of the source control
and treatment components of the selected remedial action. In
this manner, the Bureau will function in a role identical to that
of the U.S. Corps of Engineers under the Superfund program and
will oversee and manage the design and construction of the selected
remedial action. This agreement will build upon the national
interagency agreement between EPA and the Bureau for the cleanup
of NPL sites.
The Bureau wil~ assist EPA's cleanup efforts by seeking
funding for the design and construction of the water management
components of the selected remedial action. ~PA may need to
advance Trust Fund monies to the Bureau to begin certain of these
activities so as to not interupt the site cleanup process. Under
the terms of the agreement, the Bureau will reimburse EPA for
these advanced monies. .
Implementation of the selected alternative is expected to
proceed under a phased approach, with monitoring following the
. co~struction of each component remedial action alternative. .
This will allow EPA to fully determine the efectiveness of each
alternative. The phased approach will be implemented in the
following manner:
OPERABLE UNIT
o
Cappina above RicM~ond orebody
Design - 6 ~onths
Constiuction - 9 months (under suitable weather conditions)
o
Surface Water Diversions
Design - 12 months
Construction - 18 months
o
r.nlarge~ent of Sprinq Creek Debris Dam
Design - 18 months
Construction 18 months
(This component will not begin RD/RA until all the source
control, treatment (if needed) and water management components
have been constructed and monitored for their effectivene~s).

-------
- 68 -
o
Richmond Hydrogeologic Investigation
The object of the investigation. is to:
:'~ '. .: .
. .
1.
Identify the main sources of inflow and AMD to the
underground ~ine workings;
2.
Determine the vertical and lateral distribution of
hydraulic head and permeability; and

Evaluate slope stability and the strength of geologic,
material.
3.
These objectives' will be accomplished, in part, through a
groundwater drilling program and an assessment and survey
of the underground mine workings. This investigation may
identify another fill material or source control measures
that may be equally or better suited for the Iron Mountain
Mine site. Should this be the case, Region IX would propose
to expand the LDCC pilot test described below to include an
examination of these altern~tives. . .
o
Pilot and Demonstration Test of Low-Density Cellular Concrete
1.
Pilot Test
The objective of this test is to determine the proper
formulation of LDCC to withstand attack arid corrosion from
AMD. This will include a) laboratory test that will examine
the effects of acid. attack on various cement and additives;
b) adhesion and fracture and interface leach tests to
determine the ap?licability of LDCC to an acid environment;
and c) d~termi~atio~ of the geotechnical and hydrologic
characteristics of LDCC.
2.
Demonstration Tests
A small-scale demonstration test, and possibly a larger-scale'
test, will be conducted in the underground mine workings;
this will requir~ the partial rehabilitation of the Richmond
adi~~ If a larger-scale test is deemed necessary, it will,
in all likelihood, be conduct~d in tha Lawson portal; in
eff.ect, this test will serve as th~ first phase of the
implementation ~f LDCC.
The final scope and cost of the ground 'water investigation
and the LDCC pilot and demonstration test are currently in
the process of being fully developed.
o
Implement perimeter control as needed to minimize direct
contact threat.

-------
SH.Tt Of CAliFOANIA-HEAlTH "'NO wElF...R£ "'GeNCY
f4 +to..C.h~<':,! t 2-
GEOIG£ OEUICMEJIAN. Go-..
DEPARTMENT OF HEALTH SERVICES
""'-'i'OXIC suISTANCU-CQft?RO'.. DlV.q1Ollit"'" "r_'~'4-t.
-------
t\ I' .
fo.,-::ith T.~kat3
-
.'
. . .
.:'~ '.
I.!:":d-=C~t"~".::d min.e:- :'T':-t'king~' :t5 ~ ;3')Ur':'-= ,:,r)ntl'(',l £':'1' "'\,:,L,j mi:'I-:
dl'.::in:'t~-= (..1.MD) .b-: r~s~l'v~d '.mtil th~ r-:sults ,)f th~ pii,:.t :l!Ld
.j,,:m''';':"lstr:o.t.'L,n +_.~sts-';'t':":~ its t''':.~sibility. The: ROD's grr:,und t.1~t-':r
i:1'.'~stigati':-n to -=valu~t~ L['C'-:' in,je(:.tiQn sh')ul-:i be br',aden-=.J t..)
i~clude a hydrog~olo~ic Ln~esti~ation of ~low ~aths in the hi~hly
fr3ctur~d rock ~one~-
W-:: .t'e':-~'mm~nd immedi a t,d imp l-=men ~ at. i ,)n ';) f -:,per3.b le units 1r,:,,: 3. t~d
,;,n r.~r upstream '~f Iron H'..;,untain Hine prc-perty whir;h ar~
un3if~~~ed by the ~-':su1t3 ()i the ~ilot/demonstration testing Qi
the'LDGC. We req~~~t, however. a mor~ detail~d analysis of the
~0St3 t~ the Stat~ ear im~1ementation and operation and
:!l3int~nan':e of these units. Specifi::ally, we need to know the
St3.t~'.5 share ()f th-=~~ CQsts f')r :3tat-= fiscal years 1986-87 and
1~~87-8~.
SFA sh')uld sp-=.~if'; in tb-,: R0D th~t ~dditi'.)nal remedies will - be
implement~d if sit~ cl~an-u? 0bjectiv~s are nat met by the
prop0sed plans or if impl~mentiti0n of the plans create~ a
':(.mditi,:'n of imminent. and/~)r sul:stantial endangerment.
Finally~ th~ planning and d~sign of the op~r3ble units and of the
LOCe pilot and dem~nstr3ticn t~st3 must include a DHS input,
revi~w and approval process.
AMD at Iron Mount3.in Mine pos~s a s~ricus environmental threat.
.;ud we look icrward to wod:ing w~th EPA tr.;-wards a solution.
fl~33e ~ir-=~t fut~re ~ommunica~i0n t~ the att~nti0n of:
Anthony J. Landis. P.E.. Chief
Sit~ HitLgati0n Un:t
Northern Cali~0rnia Secti0n
D~~artment o£ Health S~rvi~e!
1250 Power Inn R~ad
Sacramento, CA 85826
~f '.'ou.r staff have 3.:1:: '=lue::::.:':ns t-egardi:1g tL~s~;':'mments. .pl~!tse
::3'.'e them contact Cawl3..:e A. t'kG:.h~n)t:L~r ,:,ftL~e .:!.t ': 916: 7:;9-
:3 '.)'j:: . .
cc:
Mr. William Crooks, RW:CB, . ramento
County of Shasta, DPW, Redding
:"!.::,: r~lY'@?

.- t~ft!7 :' . ~
J mes T. A en. Ph.D.
Jhi~i. Northern California
~..::ct i,)n
...

-------
STATE OF CALIFORNIA
. . a..c.\n, ~.."'\t" "3
CAUFORNIA REGIONAL WATER QUALITY CONTROL BOARD-
CENTRAL VALLEY REGION . .
3201 S STREET
SACRAMENTa. CALIFORNIA 95816-7090
PHONE: (9161445-0270
GEORGE OEUKMEJIAN, GOtfflMOr
~...,. ,
~... it

'. .
'. .
'......,..'
.'
.' .
,'. '. .
. .
9 September 1986
. .
Mr. Keith Takata, Chief
Environmental Protection Agency
Superfund Programs Branch (T-4)
Toxic Waste Management Division
215 Fremont Street .
San Francisco, CA 94105'
FINAL COMMENTS - REMEDIAL INVESTIGATION/FEASIBILITY STUDY FOR IRON MOUNTAIN MINE
This letter contains the Regional Board staff's final comments and recommenda-
tions regarding a CERCLA cleanup program at Iron Mountain Mine. These comments
and recommendations are based on our review of the December 1984 Remedial
Investigation Report, the August 1985 Feasibility Study, and the July 1986
Feasibility Study Addendum.. . -
Our own goals and objectives for an acid mine drainage control program at Iron
Mountain Mine are as follows: .
1.
Improve water quality in the Sacramento River downstream of Kesw1ck
Dam so as to protect aquatic life and eliminate potential impacts on
domestic water supplies in this portion of the river.
2.
Improve water Quality in lower Keswick Reservoir and the Spring
Creek watershed to restore some measure of beneficial uses in these
waters.
3.
Implement a mine drainage control program which provides assurance
of long-term effect 1 veness wi th mi nimum operat1 ng and mai ntenance
needs. (The control program should not be dependent on future water
storage and dilution policies, and should consider the inherent
instability of the mountain area.)
In reviewing combined alternatives CA-1 through CA-9, we believe that implemen-
tation of CA-9 would most effectively achieve the above-stated goals.' We concur
with the phased approach to implementing CA-9. Capping of the ground surface
aver the Richmond are body should be initiated as soon as possible, as should
the recommended pilot studies needed to determine the feasibility of using low
density cellular concrete (LDCC). .
We support a request for funding of the principle water management actions; the
upper and South Fork Spring Creek Diversions and enlargement of the Spring Creek
Debris Dam. The design studies for these fac1l1t1es should proceed. However,

-------
. .
Mr. Keith Takata
-2-
9 September 1986
we recommend that the diversion fac1l1tie~'on South Fork a~'upper Spring Creek
be designed with the capability of,releas1flgwater downstream to control pH in
lower Spring Creek and Spring Creek Reservoir. The need for pH control in
Spring Creek ReservQ1r-w11l depend ultimately on the success of the source
control program. With adequate source control, it may be possible to raise the
pH to a level which would cause metal precipitation in Spring Creek Reservoir as
opposed to Kesw1ck Reserva1r, where metals currently precipitate. In addition,
any plan to construct water storage and diversion facilities for the purpose of
adequately diluting acid mine drainage would be inadvisable without a long-term
agreement with the Bureau of Reclamation concerning operation of these facil-
ities in conjunction with releases from Kesw1ck and Shasta Dams.
.-.
We recommend that the upper Sl1ckrock Creek Diversion be included in the initial
phase implementation only if initial studies indicate that the waste rock
material, wh1chpresumably produces the Big Seep discharge, will not be used in
the formulation of the low density concrete.

To summarize, we recommend that the Superfund cleanup program at Iron Mou~ta1n
Mine proceed as follows:
Phase I
o Surface capping of the ground overlying the Richmond ore body.
o Pilot and demonstration' studies on t"e feasibility of LDCC.
o Request funding for water management alternatives and initial design
studies.
o Evaluate water quality impacts.
Phase II
o Implement filling of the underground workings with LDCC if Phase I
studies indicate effectiveness.
(or)
o Implement alternative source control, such as lime/limestone or other
treatment of ~or point sources.
o Evaluate water quality impacts.
Phase III
o Complete water management alternatives {if needed}.'
o Evaluate water quality impacts.

-------
Mr. Keith Takata
-3-
9 September 1986
. .
In conclusion, we wish to express our 'appreciation for:~"e efforts of your
. agency and CH2M Hill in completing the Remed1'a1' Investigation/Feasibl1ity Study
and helping to resolve this long-standing water quality problem.
VJ;QL.U~

WILLIAM H. CROOKS
Executive Officer
. .
cc:
U.S. Bureau of Re~Jamation, Sacramento
Department of Fish and Game, Region I, Redding
Department of Health Services, Sacramento
Water Resources Control Board, Division of Water Quality,
CH2M Hill, Redding
Sacramento

-------
RESPONSIVENESS SUMMARY
Iron Mountain Mine
Redding, California
EPA 48.9L17.0
September 23, 1986

-------
- ------ -- -.-- -..
-- --"
CONTENTS
Introduction
Community Relations Activities
Concerns Raised Prior to the Feasibility study
.Conunent Period-
Concerns Raised During the Feasibility Study
Conunent Period
Public Conunents on August 2, 1985, Public Comment
Feasibility Study
August 2, 1985--List of Commenters
Category 1--General Conunents on Feasibility
Study Report .
Category 2--5tudy Findings and Methodology
Category 3--Fishkill Methodology and Results
Category 4--Environmental and Public Health
Hazards
Category 5--Need for Remedial Action
. Category 6--Costs of Remedial Action
Category 7--Timeframe for Implementing
Remedial Action
Category 8~-Liability for Iron Mountain Mine
Problems
Category 9--Placement of Iron Mountain Mine
on the NFL
Category lO--Availability of RI and FS
-Reports/Public Comment Period
Category 11--Technical Input and Review of
the RI/FS
Category 12--IMMI Prqposal
Category 13--0ther Remedial Action Alternatives
Gategory14--Preferred Remedial Action
Category 15--0ther Concerns (Miscellaneous)
Public Comments on July 25, 1986, Public Comment
FS Addendum
July 25, 2986, FS Addendum-List of Commenters
Category Al--General Comments on the FS Report
Category A2~-Study Findings and Methodology
Category A3--Environmental and Public Health
Hazards .
Category A4--Costs of Remedial Action
. Category AS--Liability for IMM Problems
. Category A6--IMMI Proposal
Category A7--0ther Remedial Action Alternatives
Category A8--Preferred Remedial Action
Category A9--0ther Concerns
Category A10--Proposed New Combined
Alternatives CA-8 and CA-9
Page
1
1
2
3
3

3
6
9
23
32
45
46
47 .
48 -
49
51
54
67
70
74
79
80

80
82
84
88
89
91
92
94
96
98
100

-------
CONTENTS
Gategory A-11--CommentsRelating to
Component Alternatives
Category A-12--Comments Related to the Clean
Water Act
Category A13--Comments Related to Point of
Compliance
Page
105
116
121
RD/R84/014
.-.

-------
RESPONSIVENESS SUMMARY
IRON MOUNTAIN MINE SITE
-REDDING, CALIFORNIA
August 1986
INTRODUCTION
The purpose of this Responsiveness Summary is to document
the following items for the public record: (1) the concerns
and issues raised by private citizens and governmental agen-
cies during the remedial planning process, (2) comments and
questions raised during the public comment period on the
Feasibility Study, and (3) the response of EPA to these com-
ments and concerns.
@OMMUNITY RELATIONS ACTIVITIES
The following community relations activities were undertaken
to inform interested parties and solicit their comments
throughout the Remedial Investigation (RI) and Feasibility
Study (FS): . .
o
communit¥ Relations Plan. Interv~ews were con-
duct~d w1th local and state agenc1es, elected
officials, and interested organizations in
August 1983. The concerns and information needs
identified during the interviews were used to
design a Community Relations Plan for the site.
o
Information Repositories. Information repos-
itories were established at the Shasta County
Library and the California Regional Water Quality
Control Board office in Redding. Copies of rele-
vant technical reports and other written materials
were available for public review at these
locations.
o
Fact Sheets. Fact sheets were distributed to the
project mailing list in April 1984, January 1985,
August 1985, and July 1986. The fact sheets pro-
vided updated information about the activities,
schedule, and findings of the RIfFS.
o
Public Comment Period and Public Meeting. A.
3-week public comment period for the August 5
Public Comment Feasibility Study report was held
from August 2 to 23, 1985. A public meeting to
discuss the FS was held on August 15, 1985. The
public comment period and meeting were announced
in the August 1985 fact sheet and in display
advertisements placed in the Sacramento Bee on
July 19, 1985, and The Record Searchligh~
1

-------
(Redding) on July 20 and August 10, 1985.
Approximately 40 citizens plus representatives
from local,. state, and federal agencies attended
the public meeting.
o
Public Comment Period. A 3-week public' comment
period for the, Public Comment Feasibility Study
Addendum (submitted July 25, 1986) was held. The
public-comment period was announced in the July
1986 fact sheet and in display advertisements
placed in the Sacramento Bee and the Record
Searchlight (Redding) on July 8, 1986.
o
Press Release. A press release was issued on
August 30, 1985, to announce the availability of
the final Remedial Investigation Report. .
. .......
CONCERNS RAISED PRIOR TO THE FEASIBILITY STUDY
COMMENT PERIOD
A number of concerns were raised during the interviews 'held
for the Community Relations Plan in August 1983. The
Regional Water Quality Control Board (RWQCB) has also
received inquiries and concerns at meetings and in telephone
conversations ~ince its involvement with the site beginning-
in 1976. These cOmments and concerns are summarized below.
. -0
I
I
o
Impacts on Fisheries and Tourism. The negative
impact of acid mine drainage on sports and commer-
cial fisheries, tourism, and the environment in
general was the major concern expressed by
resource agencies, local government, sports
fishing groups, tourist-related businesses, com-
mercial fishing groups, and the League of Women
Voters.
o
Drinking Water Quality. Because the City of
Redding water supply has not been affected to date
by acid mine drainage, drinking water quality has
not been a major public issue. However, the RWQCB
has received several inquiries about drinking
water quality since its involvement with the site.
Groundwater Quality. Two residents with wells
located on property downstream of the site have
appeared at RWQCB meetings and have called RWQCB
staff on a few occasions to inquire about Iron
Mountain Mine activities.
2

-------
.' "
o
Fundingbf Sit"e Cleanu~. Local officials reported
receiving a fewinquir1es about why Iron Mountain
Mine, Inc.,. is not paying for site cleanup. There
was concern that taxpayers' money was being spent
to solve a problem created by a potentially respon-
. sible party.
CONCERNS RAISED DURING THE FEASIBILITY STUDY COMMENT PERIOD
The concerns raised during comment periods are separated
into two groups in this summary:
1.
Public comments raised during the review period of
the August 5, 1985, Public Comment Feasibility
Study.
2.
Publi~"comments raised during the review period of
the July 25, 1986, Public Comment Feasibility
Study Addendum

PUBLIC COMMENTS ON.. AUGUST 2, 1985,
PUBLIC COMMENT FEASIBILITY STUDY
Eighteen individuals, organizations, and agencies submitted
comments on the: Feasibility Study at the public meeting on
August 15, in writing during the public comment period, or
both. The following list includes the names of the comment-
ers, their affiliation, whether their comments were oral or
written, and the manner in which their comments are identi-
fied in this report.
AUGUST 2, 1985 FS--LIST OF COMMENTERS
Bruce Boyer, IMMI Consultant (public meeting and written),
. Boyer 

California Air Resourcers Control Board, ~
California Department of Fish and Game (public meeting and
written), ~

California Department of Food & Agriculture, Agriculture
California Regional Water Quality Control Board (Redding)
(public meeting), RWQCB

Chico Fly Fishing Club (written), Chico Fly Fishers
Gary Collier, Citizen (public meeting), Collier
Davy McKee Corporation (public meeting and written), Davy
McKee-Morgan, Davy McKee-Turk
3

-------
Iron Mountain Mines, Inc., (public meeting and .written),
IMMI-Arman, IMMI-Foster.
.
Arthur Katzakian, Jr., Citizen (written), Katzakian
Daniel C. McLean, IMMI Metallurigical Consultant (public
meeting and written), McLean
. .
Robert S. Miller,. Citizen (public meeting and written) ,
Miller .
Orwig Nor, Citizen (public meeting), ~

Anette and Bob Rardin, Citizens (public meeting and writ-
ten), Rardin
The Resources Agency of California, Department of
Conservation-Division of Administration, Conservation
Stanley.E. Ross, Citizen (public meeting), !2!!

Sha~ta Cascade Wonderland Association (public meeting) ,
Shasta Cascade
Bill Siemering,: Citizen (public meeting), Siemerinq

Stauffer Chemical Company (public meeting and written) ,
Stauffer
u.S. Fish and Wildlife Service (written), FWS
:~~.-
Charlie Wilson, Citizen (public meeting), Wilson

Most .of the comments are from people currently or previously
associated with Iron Mountain. Mines,- Inc..,---or previous... owners
of the mine. Many of the commenters raised similar questions
and concerns regarding the Feasibility Study Report. For
this reason, the comments were paraphrased and summarized
under categories. Every attempt was made to accurately
paraphrase comments and respond to all comments that
required a response.
~
The comments and responses to them are grouped into the
following categories:
1-.
General Comments on Feasibility Study Report
2.
Study Findings and Methodology
3.
4.
Fishkill Methodology and Results
Environmental and Public Health Hazards
4

-------
Need for Remedial Action
5..
6.
Costs of Remedial Action
7.
8.
Timeframe for Implementing Remedial Action
Liability for Ixon Mountain Mine Problems
9.
Placement of Iron Mountain Mine on National
priorities List .
10. Availability of RI and FS Reports/Public Comment
 Period  
11. Technical Input and Review of RI/FS 
12. IMMI Proposal  
13. Other Remedial Action Alternatives 
14. Preferred Remedial Action 
15. Other Concerns (Miscellaneous) 
5

-------
CATEGORY l--GENERAL COMMENTS
ON FEASIBILITY STUDY REPORT
COMMENT 1-1
Five commenters (IMMI-Arman, Stauffer, Boyer, McLean,
Miller) commented that the Feasibility Study Report is
biased against IMMI and/or technically inadequate to.
responsibly evaluate the reasonableness or effectiveness of
the potential remedial alternatives. One commenter
(Stauffer) questioned the accuracy of the cost comparisons
that were presented. .
RESPONSE TO COMMENT 1-1
EPA believes th!t sufficient information and data were
available through past state sampling and EPA's Remedial
Investigation. to provide a relative comparison of the effec-
tiveness of remedial action alternatives as presented in the
Feasibility Study Report. The report is not intended to
draw conclusions about the cost-effective remedy, but to
provide EPA with a full range of alternatives from which to.
select an apprqpriate remedy. We believe the report pre-
sents an unbiased evaluation of the IMMI alternative. EPA
has also stated its willingness to consider the IMMI
alternative to the extent that IMMI can provide specific
technical and financial assurances.
EPA is confident that the feasibility level cost estimates
will fall within a -30 to +50 percent accuracy range.
Comments concerning specific technical aspects of the Fea-
sibility Study Report are responded to under the appropriate
categories of this Responsiveness Summary.
COMMENT 1-2 (IMMI-Arman)
Thousands of dollars of Superfund money was needlessly spent
or lost through. lost or destroyed equipment; two and three
engineers riding around to do one engineer's duty, such as
sampling water or supervising construction progress; lack of
engineering and inappropriate design, causing loss of man-
hours while the subcontractors were waiting for revised
plans; loss of additional hundreds of manhours while subcon-
tractors were waiting for materials to be delivered; dupli-
cation of efforts and costs in having to replace previous
construction, etc. EPA was made aware o£ this problem, but
apparently was not interested and is now defending CH2M HILL's
workmanship and Feasibility Study as satisfactory and
accurate.
6

-------
RESPONSE TO COMMENT 1-2
The design and installation of flow measuring "stations at
the five major sources and at three stations on Spring Creek
were subcontracted to another firm." This firm transported
its own rental equipment a~d materials to the site as it was
required. To our knowledge, no major time losses were expe-
rienced. This pqrtion of the project was completed within
the originally estimated cost.
The subcontractor was given the acidic characteristics of
the mine drainage, and chose to use galvanized stilling
wells. Due to acid attack, the stilling wells were replaced
with plastic pipe at three of the sites.

The only equipm~nt that was lost during the study was a
velocity meter. -~" This was not charged to the project.
Water sampling, bed measurements, and flow measurements were
taken by an environmental scientist and a technician. These
two people were required to reduce the time required for
this work so that measurements for all sites could be accom-
plished within a l-day period during a given sampling .
period. All expenditures by EPA were not inconsistent with -
the NCP. "
COMMENT 1-3 (Boyer)

Why didn't CH2M HILL defend its Feasibility Study at the
public meeting when attacked by individuals who pointed to
obvious mistakes in the report?
RESPONSE TO COMMENT 1-3
The purpose of the public meeting is to allow the general
public an opportunity to ask questions and make comments
regarding the results of the Feasibility Study. EPA's con-
tractor that conducts the study, in this case CH2M HILL, is
invited to the meeting to help EPA answer questions regard-
ing the study. They provided that service at the August 15
meeting. Once the questions and answer period is over, the
meeting is open to public comments. EPA's contractor assists
EPA~n responding to public comments during preparation of
the Responsiveness Summary, not during the public meeting.
COMMENT 1-4 (McLean)
The Feasibility Study Report is highly biased toward justi-
fying IMM's placement on the National Priorities List.
7

-------
RESPONSE TO COMMENT 1-4
EPA would like to clarify that the purpose of the Feasibil-
ity Study is to develop and evaluate remedial action alter-
natives for sites listed on the NPL. It is not conducted
for the 'purpose of placing a site on the NPL. (See also
Category 9 for further response to this issue.) The
findings of EPA's R~ support the data and information used
by the State in applying the Hazard Ranking Scoring to the
IMM site. This is a further indication that the Hazard
Ranking Scoring was properly used to evaluate the IMM site.
EPA wishes to restate that the nature and extent of the IMM
problem justifies its placement on the NPL.
COMMENT 1-5
(Conservation)
The Department of Conservation is vitally concerned with
mining activity, mineral resource conservation and devel-
opment, and the reclamation of mined lands throughout the
state. Any proposed plan or regulation that might affect
mineral resources, specifically or in general, is of great
. interest to us.
RESPONSE TO COMMENT 1-5
No response required.
8

-------
COMMENT 2-1
CATEGORY 2--STUDY FINDINGS AND METHODOLOGY
Three commenters (Boyer, IMMI-Arman, Miller) questioned the
validity of the data collection and presentation on Tables
2-4 and/or 2-6 of the Feasibility Study Report. They stated
the following points:
o
The tables show assays of soluble concentrations
higher than the total concentrations of the same
mineral. It is footnoted that there are no iden-
tifiable reasons for these differences. It is
obvious that errors were made someplace in the.
process~ laboratory technique, calculations, or
sampling. However, there was no attempt to elimi-
nate the erroneous data from use.
o
Even though samples were taken and the heavy
metals or the negative environmental attributes
were analyzed and found to be beyond the limit~ of
detection, these samples were not included.
Elimination of these "non-detectable" assays
changes the resulting averages and presents an
erroneous report.
o
The statistical inaccuracy of these tables brings
into question the validity of data collection and
analysis throughout the rest of the report. These
tables and any other sections of the report
impacted by them should be disregarded.
o
The inclusion of these erroneous data represents
purposeful "statistical cheating" and an inten-
tional bias against IMMI.

Does EPA want to stake its reputation on the firm
that prepared these tables? This same firm also
found.low levels of cadmium in Shasta Lake and
higher levels in Keswick.
o
RESPONSE TO COMMENT 2-1
All data collected followed established EPA quality
ass~rance/quality control procedures to verify the validity
of the data. In addition, ion balances were performed on
samples for which sufficient data were obtained to confirm
the data. .
For some analyses, reported soluble concentrations exceeded
the total concentrations as was pointed out in footnotes to
the tables. Field blanks processed in the same manner as
the samples did not identify contamination during field
9

-------
handling. The difference between total and soluble concen-
trations may have been depicting the standard deviation of
the analysis at the lower concentrations.

The complete data which were summarized in Table 2-6 of the
Feasibility Study Report are presented in the Remedial
Investigation Report. These data could be summarized and
presented either as- ranges or as averages. For simplifi-
cation, the average of detectable values was presented and
identified in a footnote to the table so that the reader was
alerted to how the data were presented. There was no intent
to hide this. Anyone reading the report can refer to the
total data presented in the RI report should they wish to
analyze the data for themselves.
Data presented in-Table 2-6 for the Sacramento River below
Keswick Dam represent both a "no-spill" condition from
Spring Creek Debris Dam (February 2, 1984 through June 28,
1984) and "spill" conditions in January 1978, January 1983,
and March 1983. As would be expected, the concentrations of
metals during spill conditions was much greater than those
measured during no-spill conditions, due to lower dilution
of acid mine drainage in the Sacramento River during spill -
conditions. .
COMMENT 2-2 (Boyer)
At the public hearing, the Water Board minimized the role of
19 other mines in the West and East Shasta Mining Districts
with statements like "over 90 percent of the acid mine
drainage comes from Spring Creek." This is not true, as
surveillance of the mines in the East Shasta District is
poor. This is brought-out on page 9 of the U.S. Geological
Survey 78-32, May 1978. Levels of zinc and cadmium from
t,hese mines are high. Sulfate ion can be used as a marker
for the total load of acid mine drainage entering the
Sacramento River. Heavy metals enter the receiving waters
as sulfates. On dilution with water of higher pH and ample
buffering strength, the heavy metals are precipitated, leav-
ing the sulfate ion in the water. Using sulfate ion as a
marker and according to Fish and Game and Central Valley
Water Quality Control board staffs' own analysis and tables,
Spring Creek is shown to be delivering less than 11 percent
of the total acid mine drainage in Sacramento River water
(Table 2-6), and in another of their charts, less than.
23 ~ercent of the total acid mine drainage in the water.
RESPONSE TO COMMENT 2-2
Other mines in the West and East Shasta Mining Districts
have been extensively monitored by the Regional Water Qual-
ity Control Board for a number of years. Seve~al have been
10

-------
, ,
",
',- '\ ',: , ,
issued discharge requirements with programs and schedules
for cleanup action. ,- Several- of ,these mines-do ''discharge' '
high concentrations of Cu, Zn, Cd upstream of Iron Mountain
Mine. Monitoring studies show that the impacts of these
discharges are localized, and the metal concentrations are
diluted by the 4 million-plus acre-feet of water in Shasta
Lake (the receiving water body into which these discharges
enter). Numerous sampling efforts, including those in the
EPA Remedial Investigation, have shown that metal concen-
trations below Shasta Darn (downstream from the other mines
but upstream from the Iron Mountain Mine discharge) are safe
for aquatic life. Toxic concentrations of heavy metals in
the Sacramento River occur only after the addition of drain-
age from Iron Mountain Mine via Spring Creek.
COMMENT 2-3 (Davy McKee-Turk)
-~,
The goal, of adequately protecting aquatic life in the
Sacramento River below Keswick Dam from releases of acid
mine drainage migrating from the site does not mean that the
point of compliance should be located in an area where IMMI
co~ld be adversely affected by conditions arising from,
operations and areas not under their control. Davy McKee
recommends that the point of compliance be located at a
point under the control of IMMI and that the criteria for
compliance be adjusted to allow for downstream dilution.
RESPONSE TO COMMENT 2-3
EPA and the State believe that below Keswick Dam is the
appropriate location to establish the point of compliance
for a federally funded remedial action. Should the IMMI
project be allowed to go foward in lieu of the EPA program,
the water quality standards that would need to be met at the
point of compliance would also have to be met in immediate
receiving waters. These areas would, in effect, be under
IMMI's control as Davy McKee has suggested. Meeting water
quality standards in immediate receiving waters should
ensure that water quality standards below Keswick Dam will
be met. Flows above the Spring Creek confluence with the
Sacramento River are relatively clean. In addition, com-
pliance can be checked with a direct measurement at this
point. If the point of compliance were moved above Spririg
Creek Reservoir, computations would have'to be made
regularly to predict the effect of Iron Mountain Mine,
releases as they pass through Spring Creek Reservoir,
Keswick Reservoir, and as they become diluted with variable
flows from Shasta Dam.
COMMENT 2-4 (IMMI-Arrnan)
In CH2M HILL's Feasibility Study Report, there are no data
on the pyrite tailing pile located directly on the bank of
11

-------
Keswick Lake (Sacramento River). The rainwater draining
from this pile contains leached minerals. The Regional
Quality Control Board is aware of this drainage site.
Obviously, the RWQCB does not consider this tailing pile to
be a mineral problem, or they would have included it in the
CH2M HILL investigation report; after all, the main issues
are the mineral effects on'the Sacramento River. If there
is no problem or mineral pollution concerning this pile,
then why should there be any concern with similar material
miles away on the Iron Mountain Mines property? The same
circumstances apply to the old smelter area that drains into
the Sacramento River from the bank of Spring Creek at the
Sacramento River. By not including all of the data in the
computed model calculations, the final results would be mis-
leading. It appears that these seeps or drainages from the
above two waste areas were not reported in the Feasibility
Study because it'would weaken the pollution claims against
Iron Mountain Mines, Inc. (IMMI). Also omitted were 16
mines in the West Shasta Copper/Zinc District that cause AMD
directly into Shasta Lake and the Sacramento River.
RESPONSE TO COMMENT 2-4
Discharges fro~ other mining sites into Shasta Lake were
taken into account by measurements taken above Spring Creek-
in the Sacramento River. The RWQCB has also taken measure-,
ments at Matheson and determined their contribution to the
Sacramento River to be insignificant.
COMMENT 2-5 (IMMI-Arman)
The Basin Plan objectives for mineral content in the
Sacramento River, according to a statement by Mr. Thomas A.
Mix at the August 15, 1985, public meeting, "were designed
specifically for Iron Mountain Mine." These objectives were
not for limitations on other dischargers. This represents a
very biased restraint against Iron Mountain Mine.
RESPONSE TO COMMENT 2-5
The State has adopted water quality objectives for Cu, Zn,
and Cd in the upper Sacramento River (above Hamilton City) .
These numbers were adopted at the levels deemed necessary
for the protection of all life stages of salmonids in the
river. The numbers are based on lengthy studies by the
Ca~ifornia Department of Fish and Game and researchers out-
side the state. These are receiving water objectives and,
together with the federal standards, they were identified
for the purpose of targeting a cleanup program for Iron
Mountain Mine site. '
12

-------
, .7. ". ,..
" ..'
"'. \',' :
COMMENT 2-6 (IMMI-Arman and Katzakian)
The Feasibility Study Report states that "All of the indi-
vidual unit process operations in the IMMI proposal employ
technology that has been demonstrated to varying degrees in
similar applications" and goes on to say that "No operating
commercial solution mining' facilities have been identified
which combine all the processes proposed by IMMI." The
report then expresses the concern: "Will one system working
inadequately cause the next system to fail?" These same
fears can be expressed for using any of the combined EPA
alternative plans, based on the statement in the executive
summary that "Based upon the limited available information,
it is not possible to accurately predict the overall effec-
tiveness of any of the combined alternatives." It
apparently is not known what the effectiveness and
environmental impact of employing any of the combined
alternatives would be.
Mr. Arman stated that it seems reasonable to expect some
sort of positive recommendations after the expenditure of
approximately $900,000; the most obvious result should have
been that Iron Mountain Mine did not belong on the NPL and.
the "no action" alternative should have been recommended. .
RESPONSE TO COMMENT 2-6
The Iron Mountain Mine site is very complicated with respect
to. rainfall, surface water hydrology, and the movement of
groundwater through the ore zone. The data developed during
the Remedial Investigation are the best available data to
characterize the hydrology. However, these data were col-
lected for only a brief time with regard to history. There-
fore, there are some uncertainties when estimating the
effectiveness of remedial actions affecting the movement of
groundwater through the orebody. During predesign or
design, EPA will seek to develop additional data to properly
design and construct the remedy.

1 Even though it is not possible to accurately predict the
overall effectiveness of each individual alternative, the
alternatives were compared on the same basis. EPA is confi-
dent that water quality objectives will be met with the com-
bined alternatives selected. If objectives' are not met
after the alternatives. have been implemented, EPA will, seek
to ~mplement other remedial actions to ensure that these
objectives will be attained through the Remedial Action
program.
The uncertainty about the effectiveness of the. remedial
alternatives has nothing to do with the documented fishkills
and the potential health threats that preclude the "no
action" alternative. The results of this study will be used
13

-------
. .
by EPA to select a permanent remedial action for. the Iron
Mountain Mine site. The extent of the environmental problem
alone precludes the selection of the no action alternative.
COMMENT 2-7 (IMMI-Arman)
It is stated in the Feas~bility Study Report that "all
applicable technologies were considered." The only tech-
nologies considered were a rehash of previous studies (ten
known studies funded through state and federal agencies)
that had been discarded, were incomplete, or had already
been proven not feasible. The one new suggestion was
diverting water from the south fork of Spring Creek into
Rock Creek. This one suggestion does not seem sufficient
for such a costly study.
Everything in the "study" pertained only to water runoff
caused by rainfall. No alternatives were considered,
including Iron Mountain Mines, Inc.'s proposal that involved
commercial removal or processing of the ore deposits, which
are the actual source of minerals in the water.
RESPONSE TO COMMENT 2-7
All applicable. technologies were considered in the Feasibil~
ity Study, including the IMMI proposal. Some of the alter-
natives were considered in previous studies.
The IMMI proposal is a commercial mining venture (which
includes marketing of agricultural and other products) that
cannot be implemented by EPA because EPA cannot become
involved in competing with other manufacturers of agricul-
tural and other types of goods. Therefore, this alternative
could not be evaluated on the same basis as the other
non-commercial alternatives. In addition, the IMMI proposal
was screened out because it contained insufficient data for
evaluation.
The recommencing of mining by conventional mining methods
was considered, but was considered infeasible because of the
depressed copper market and because of competition from
third world countries, which is driving copper prices do~n.

EPA.is still considering the IMMI proposal as a potential
remedial alternative. However, there are certain assurances
that IMMI would have to provide before EPA can accept its
proposal in lieu of one of the combined alternatives
presented in the Feasibility Study Report. EPA has provided
IMMI with negotiation options for further consideration of
its proposal. However, IMMI has not selected which option
it prefers for further discussion.
The Feasibility Study considered all major movement of water
that contained metals.
l4

-------
. j '.
, . . . v~..
COMMENT 2-8 (Katzakian)
On Table 2-2, averag~ chemical compositions, there appear to
be some large discrepancies between the sum total of all the
individual ions in solution with the total dissolved solids
measurements. For the Richmond Portal, the discrepancy is
19,090 mg/l. For the Lawson Portal, it is 2,390. This rep-
resents a 27.5% difference for the former and a 12.6% dif-
ference for the latter. The three other analyses are in
substantially good agreement.
Discrepancies like this cast doubt on the correctness of. the
analyses made in that set. Why was this data not checked
for internal consistency and rechecked when discrepancies
were found?
RESPONSE TO COMMENT 2-8
The original data from which those data presented in
Table 2-2 were averaged and were checked for an anion-cation
balance. Based on this check, data found to be in error
were deleted. A comparison of total dissolved solids (TDS)
with the cations and anions presented in Table 2-2 may not.
necessarily totally agree, given the fact that every element
and compound i~ the solution was not analyzed for, and
because heating of the sample in the TDS analysis can drive
off volatile compounds such as carbonates.
COMMENT 2-9 (McLean)
No solid factual data or design criteria are provided to
support most of the alternative project expenditures propo-
sed, hence there is no .way for anyone to judge how complete
and accurate any of the project designs or cost estimates
are.
The O&M costs are particularly misleading in that annual O&M
costs are not given and there is no indication of the life
span and depreciation rate of each alternative assumed in
the calculations.
There is no indication as to how perpetual operations will
be funded and by whom.
RESPONSE TO COMMENT 2-9
The conceptual design criteria and cost estimates are given
in the appendices of the Feasibility Study Report.

On page A-l of the Feasibility Study Report, the discount
rate and life span are given respectively aslO percent and
30 years. .. .
15

-------
The St~te of California is responsible for O&M requirements
after the alternatives are implemented.
COMMENT 2-10 (McLean)
Mr. McLean submitted the following questions regarding the
lime neutralization treatment:
1.
What is the expected period of operation and what
are the estimated annual 0 & M costs and depre-
ciation allowances?
2.
. Will the above costs be covered .by Superfund money
in perpetuity? If not, what is the expected
source of operating funds?

How lQng will it take to prepare EIS's for stream
diversions, the nine-mile pipeline, and the haz-
ardous waste production and disposal operation
which a neutralization plant producing Cu,-Zn-Cd
sludge will be?
3.
4.
Which plant size is actually recommended?
5.
Has the 90-acre site on federal land actually bee~
clear~d as a hazardous waste disposal site?
6.
What are the design criteria on which sizing and
costing of the plants are based?
RESPONSE TO COMMENT 2-10
Should the lime/limestone neutralization process be a
selected alternative, it may be necessary to operate it
indefinitely. Present worth O&M costs are. presented in
the FS report. Depreciation allowances are not inclu-
ded; however, discount rates for O&M costs are shown in
Appendix A of the Feasibility S~udy Report.

The State of California will fund O&M during the life
. of the project. Federal fund money would have been
available to fund the first year of O&M to ensure that
the RA was performing as expected.
1.
2.
EPA has determined that the RI an dFS process is. .
. functionally equivalent to NEPA and therefore, an EIS
will not be required.

No plant size was recommended. A range of plant sizes
was presented in the FS report to allow EPA to select
the final remedial action.
3.
4.
5.
The 90-acre site on federal land is not part of the
Alternatives CA-7, 8 or 9.
16

-------
6.
j ~..\ ," "...,", .'

A lime/limestone neutralization process was piloted for
the RWQCB at.;the.""'1:MMi~-site~';' The'resu1 t~F Of' 'this . study""".'"
were presented in the report identified as Reference 1,
Appendix F of the Feasibility Study Report. The design
criteria, on which sizing and costing of the lime/
limestone neutralization plants were made, were based
on a scale-up of th~design criteria in that reference
based on flow and acidity.
COMMENT 2-11 (McLean)
Mr. McLean submitted the following comments and questions
concerning water analyses and analytical methods:
The water analyses presented, especially those for cadmium
in the Sacramento River samples, indicate that little or no
quality control.~was applied at the laboratories making the
analyses. Nowhere in the report is there any. discussion of
the reproducibility or accuracy of the used (sic) for cad-
mium in the fractional microgram concentration range, yet
this is one of the most critical elements in the whole
study. The study infers that the laboratories can reliably
distinguish between levels of 0.2 ppb of Cd (the RWQCB tar- ,
get for the river) and 0.4 ppb, which is unacceptable. .

If the standard' EPA method for cadmium (Method 213.1) was
used,' its lower level of detection is 5 ppb. This obviously
is not a reliable method, per se, for water samples at lower
concentrations. If some other method was used, it has not
been described, and standardization data indicating its
reproducibility and standard deviation at Cd levels less
than 5 ppb are not reported. Inclusion of this type of data
is essential to establish the authenticity o~ the analyses
reported for. this critical toxic element, yet the subject is
completely ignored.
In Tables F-1S and F-16 of the draft Remedial Investigation
Report, about one-half of the analyses show soluble Cd as
being greater than total Cd, a chemical impossibility.
Similar illogical data for zinc, copper, and iron are con-
tained in essentially all of the analytical tables in both
reports. This is shrugged off in several tables by a foot-
note saying that it cannot be explained. .

These "unexplained" data actually indicate both poor quality
contro~ of analytical procedures and/or insensitivity of the
methods used to the range of metal concentrations involved.
They also indicate an obvious lack of competence by the study
investigators in conducting and monitoring a critical chemi-
cal analysis program. .
If any credence is to be attached to the river water
analyses or the computer outputs based on them, a full
description of the actual methods used, their methods of
17

-------
standa~dization, standard deviations and the quality control
procedures used durin9 the study should be included in the
report. .
I
i
Questions to be answered under this topic are:
4.
5.
6.
7.
1.
What analytical-methods
analyse$ af Cu, Zn, and
limits of detection and
range of 0.1 to 5 ppb?
were used for the water
Cd? What are their lower
standard deviations in the
2.
What laboratory qualification and quality control
procedures were followed in the water analysis
program?
3.
What s~~ps were taken to determine why so many
soluble values exceeded total values?
Where are the data for periodic duplicate samples
that are required to be run in any EPA
investigation?
Which values (total or soluble) were used ~n th~
computer program?
. -
What does the term "lOa-Day Fishery Evaluation for
Mortality" mean (as used in Tables G-13 through
G-16) and how does this relate to 96-hour LD-50
da ta ? .
Were the data in Tables G-13 through G-17 used as
the principal bases for acceptance or rejection of
the various alternatives?
RESPONSE TO COMMENT 2-11
Copper, zinc, and cadmium were normally analyzed using
ICAP. Low level concentrations were analyzed using
graphite furnace atomic adsorption. Specific detention
limits and .standard deviations vary with the sample
matrix and metals concentrations. These data are
available in the data packages provided by the Contract
. .Laboratory Program (CLP) laboratory. Therefore, to -
determine the detection limit and standard deviation
for a specific set of data, the reader will have to
. refer to that specific data package which may be
obtained from EPA.
1.
2.
The laboratories used for analyzing the samples col-
lected in this study were part of EPA's CLP. The.
specific qualifications for laboratories participating
in the CLP and the quality control procedures they must
follow are described in Contract Laboratory Program,
Statement of Work, Inorganic Analysis, May 18, 1982 and
July 1984 (SOW # 784).
18

-------
."'" .' ~- ..... _..
3.
Where possible, the samples containing higher soluble
,.., than 'total" concentrations"'of,' meta-Is' were "re--a:11'alyzed~to"~"_" ",
confirm the results.
4 .
The results of the periodic duplicate, samples are con-
tained in the EPA QA/QC package of results. These were
not included in the.RI report.

The computer model used both total and soluble metal
concentrations. Total metal concentrations were used
in Spring Creek. Soluble metals were used in Keswick
Reservoir and in the Sacramento River.
5.
6.
The "100 Day Fishery Evaluation for Mortality" was a
lOa-day period used in the USBR model. The 96-hour
LD-50 data developed by the California Department of
Fish and Game were applied to this lOa-day period in
the USBR model. '
7.
The number of spill days and the metals concentrations
were used to compare alternatives not meeting the
objectives as to their relative effectiveness.
COMMENT 2-12 (McLean)
Mr. McLean submitted the foliowing comments and questions
concerning groundwater studies:
IMMI was told at a meeting in the CH2M HILL offices in
Redding in August 1984 that groundwater study and monitoring
would be a major segment of this study to determine the
extent of groundwater pollution of surrounding areas. Sev-
eral monitoring wells were placed on the IMMI property and
samples taken periodically. However, the only groundwater
data presented are for three holes drilled in the Richmond
ore body by Ruskin at a depth to water of less than 50 feet
(see Table 6-11 in the Draft Report). We request answers to
the following questions:
1.
Where are the groundwater data from the special
wells put in by CH2M HILL?
2.
What groundwater flow measurements were used to
determine the effectiveness of the Richmond ground-
water intercept alternative?
3.
Did the groundwater studies show that there is no
movement of groundwater away from the ore body and
no contamination of any surrounding groundwater?
4.
How long will it take to complete the preliminary
work required for Groundwater Interception Alter-
native SC-6 as outlined on page 7-30?
19

-------
5 ~.
Did a competent mining engineer study and approve
of this alternative?
RESPONSE TO COMMENT 2-12
1.
The data from the Rich~ond Groundwater Investigation
are presented in the" Final Remedial Investigation
Report, I~on" Mountain Mine, August 1985.
2.
Measurements of temperature, discharge, and chemical
concentration at the Richmond portal along with the
temperature of groundwater measured at the CH2M HILL-
installed monitoring wells were important measurements
used to determine the effectiveness of the Richmond
groundwater interception program. These data are.
available ~p -Appendix I of the Final Remedial Inves-
tigation Report, Figures I-3 through I-7.
Along with measurements made at the Richmond portal,
packer tests conducted on two of the monitoring wells
and pump tests conducted on all four of the monitoring
wells are available in sections of Appendix I labeled
"Packer Permeability Tests" and "Pumping Test Results. It. .
Table I-1 summarizes the results of the pumping tests. -

Groundwater hydraulic gradients were calculated from
water levels observed in the four monitoring wells.
Well hydrographs (water levels) are graphically depict-
ed in Figure I-2.
3.
The groundwater studies showed that there was no con-
tamination of groundwater in the four monitoring wells
installed by CH2MHILL. It is possible, but not
probable, that contamination of groundwater occurred
downslope of Iron Mountain Mine. Hydraulic gradients
in the vicinity of the monitoring wells appear to be
toward the mine. However, more wells would have to be
drilled to prove that the gradient is toward the mine
cavity along the axis (east and west ends) of the mine.
4.
The preliminary work required for the groundwater
interception Alternative SC-6 would take at least 6 "
_.months. The preliminary work is outlined on page I-3
of the Final Remedial Investigation Report (Richmond
Groundwater Investigation recommendations). The time
.. includes: . . .
o
1 to 2 months for drilling new wells and setting
up a pumping and monitoring system

4 to 6 months of monitoring discharge out of the
Richmond portal
o
o
2 to 4 weeks of evaluation
20

-------
i. "
!;>
, .
l '"
EPA's Mining Engineering Group and a representative
from the u-. S~-' Burea.u"of'~Mines','both- memb'e-rs of- the
Technical Advisory Committee, reviewed the Feasibility
Study.

COMMENT 2-13 (Miller)
5.
The final select~onof alternatives as described by alterna-
tive, Sections 7 and 8, and their evaluation, Appendix F,
plus the costs thereof, Appendix A, leave much to be desired
to make an intelligent selection of an alternative with a
potential price tag of 42.8 million dollars.

Consider the item of capping as an example. The recommended
procedure, soil cement, requires that'the soil? body which
will have cemen~ added to it must be first classified as to
percent sand, silt, and clay. This is required to determine
the amount of cement required. Thickness of the soil cement
also is required. There is no indication that this has been
done. Some soils are not amenable to this type of treat-
ment, such as gravels and coarse sands.
Construction requires the cement (a specified amount to
achieve desired. results) to be thoroughly mixed with soils
and the mixture'material, then watered and rolled. ,While
some of the area involved would be amenable to this type of
operation, the steeper hillsides would not. Terracing
would, in some areas, not be possible. Without proper
installation, this type of treatment is very questionable.
Incidentally, I personally have supervised this type of
installation. '
I would like to see the basis for arriving at the costs and
documentation of feasibility, if they exist.

The groundwater interceptor system is doubtful. In theory,
such a system might be possible; however, in the real world
and on the mountain proposed, success is very doubtful.
The idea is like placing one tile drain through a IOO-acre
field and expecting it to drain the entire field.

In tqe scheme proposed, there would be too many alternative
paths water could take, instead of finding its way into the
periphery tunnels.
Enlarging the dam is practical; however, USBR has this
responsibility and IMMI or the previous Owner (Stauffer)
should, in no way, be liable for this action inasmuch as the
original Spring Creek dam project was not built to the rec-
ommended size at the desire of ,Congress.
21

-------
The same applies. to .tl1eSW.diversion.
approved by Congress. .
This also was not
If these two actions are desired, then USBR should be the
responsible party with retribution coming from Mountain Cop-
per Company, if possible.. .
RESPONSE TO COMMENT 2-13
A design of the soil-cement mixture was not performed as a
part of the Feasibility Study. This activity is usually a
part of the design of the remedial measure. Based on recon-
naissance of the site, it appears there is sufficient sur-
ficial soil that a soil cement cap can be constructed using
ons i te soils. How.ever, during final design, it may be found
that some.import,i,pg of soil or fly ash is necessary or is
more economical than adding additional cement.
The cost estimate provided in th~ Feasibility Study Report
does allow for some regrading of the site to reduce the
steepness of some of the slopes. However, in some steep
areas it may be found that some other permeability-reducing.
measure is more appropriate during final design. It should
also be remembered that infiltration is not as great a prob--
lem in steeply sloping areas because the runoff percentage
of rainwater is naturally higher in these areas. But as
commented, there are areas that are not practical for cap-
ping--an example is the sides of brick flat pit.
The basis of cost for the cap assumes regrading of portions
of the site and a 12-inch-thick cap extending approximately
100 feet beyond the surface projection of the ore body,
excluding the sides of brick flat pit. It also includes
some interception ditches that will accumulate the runoff at
intermediate locations along the hillside.

The basis for arriving at costs are outlined in the Appendix
of the Public Comment FS. A cost comparison is made for the
alternatives on a present worth basis.
The interception tunnel and drill holes should be capable of
significantly , reducing the groundwater inflow into the ore
body. Dewatering tunnels have been used in the past to
dewater mine workings. This method, in addition to using
the interception tunnel, also includes the use of relatively
closely spaced drill holes to increase the likeiihood that
high permeability areas such as fractures, joints, or faults
will be drained by the interception system.
The analogy of a tile drain in a 100-acre field may not be
directly applicable to the interception method proposed in
the Feasibility Study. However, if the tile drain was up to
500 feet in depth and was continuous around the site and ~o
the ground surface, it would probably be effective in reduc-
ing the groundwater surface inside its perimeter associated
with a high exterior ground surface. .
22

-------
- wi th regard. to_-E3Illarging. S.prip.(:L Cr.~_ek Darq _and implementing
the other water manag~ment alternatives, the USSR has --
indicated that it will participate with an interagency
agreement with EPA and may choose to recover its costs under
the authority of CERCLA.
~-li th regard
the dam and
in business
party.

COMMENT 2-14 (Shasta Cascade)
to responsible parties for the implementation of
diver~ions, Mountain Copper Company is no longp.r
and the USBR is not considered a responsible
will the remedial action alternatives include restoration of
Spring Creek and Slickrock Creek 50 they are able to support
aquatic life? -- . .
RESPONSE TO COMMENT 2-14
None of the remedial alternatives include a restoration pro-
gram for Spring Creek or Slickrock Creek. The source
control and treatment technologies could incidentally
improve conditions in portions of these streams. However,
it is not anticipated that these receiving waters will
support aquatic- life following the implementation of
remedial alternatives which include these technologies.
23

-------
CATEGORY 3--FISHKILL METHODOLOGY AND RESULTS
~
COMMENT 3-1
Three commenters (Boyer, McLean, and Miller) had questions
concernipg the computer model used in the Feasibility Study
and specifically the 72 percent fish mortality estimate
given in Appendix G of the Feasibility Study Report. These
commenters wanted to know what species of fish this percent
applied to, what section of the river was modeled, and what
life stages of fish were modeled. One commenter wanted to
know what computer model was used, how it worked, and what
input data were used.
RESPONSE TO COMMENT 3-1
-"
Two computer models were used in the Iron Mountain Mine
study. The first was a water quality model that uses a mass
balance approach for accounting for heavy metals in the
Spring Creek watershed. This model is similar"to the USBR
Spring Creek toxicity model which was developed for the Cen-
tral Valley Fish and Wildlife Management Study. The second-
model is a fish toxicity model which was developed by the
USBR and is part of their model described above~

Spring Creek Water Quality Model
The Spring Creek water quality model was used to compare the
relative effectiveness of each of the combined alternatives
that were evaluated. The alternatives were compared on the
basis of meeting the two alternative sets of cleanup objec-
tives described in the Feasibiltiy Study Report. The point
of compliance for meeting these objectives is in the Sacra-
mento River immediately below Keswick Dam. "

The model was calibrated to 1978 and 1983 using historical
efficiencies for the Boulder Creek and S1ickrock Creek cop-
per cementation plants. .
The model was then set up for base case years for each of
the four historic years studied (1978, 1980, 1981, and"
1983). This consisted of estimating metal loadings for cop-
per~. zinc, and cadmium at the five major source1ocations
and the other sources as they were combined in Boulder" Creek
an~ Slickrock Creek. These base cases assumed no remedial
act~onsin place, including no copper cementation plants.
To compare the effectiveness, ~etalload reductions were
estimated for each source depending on which component
alternative was being evaluated. The component alternatives
(i.e., capping, groundwater interception, diversions, copper
24

-------
cementation, .- .trea.tment.."..debris.._.da.m.....en.la.r.geme.n.t.,. _e.t.c,.) ...we.r.e.. . "-..
then combined in a manner to meet the two different objec-
tives depending on which case year was evaluated.
Fish Toxicity Model

The fish toxicity model used concentrations of copper, zinc,
and cadmium, which are computed in the Sacramento River
below Keswick by -the water quality model, to estimate Sacra-
mento River salmon mortalities. These concentrations vary
at different locations down to the river based' on inflow
from tributaries to the Sacramento River. The mortality
estimates were based on California Department of Fish and
Game bioassay studies (published information) and data which
were compiled and summarized by the u.S. Fish and Wildlife
Service on the distribution. The model considers all life
stages of fish fh the river. The model estimated the
effects of metals on fish mortality from Keswick Dam to Red
Bluff (approximately 60 river miles).
The purpose of the fish toxicity model was to make a rela-
tive comparison of the effects on fish for alternatives or
combinations of alternatives that do not meet the objec-
tives. It was not for the purpose of projecting fishkills
to justify the existence of IMM on the NPL. The documented
observed fishkills, even without the computer model, demon-
strate a potential environmental threat. .
This model was calibrated to the 1978 case year by using the
estimated 72 percent fish mortality figures from the USBR
study. This figure was the estimated percent of fish
(salmon only) that would have been killed in 1978 if some
would not have been caught and transported to Coleman Fish
Hatchery. The estimate took into account all life stages of
fish .and was for 60 miles of river from Keswick Dam to Red
Bluff.
COMMENT 3-2
Three commenters (Boyer, IMMI-Foster, and Katzakian) ques-
tion whether fishkills in the Sacramento River are a problem
and do not believe the documented fishkills are related to
discharges from Iron Mountain Mine. Some believe the fish-
kills are based on a projection by the computer model.
RESPONSE TO COMMENT 3-2
The California Department of Fish and Game (DFG) has been
involved since the early 1940's with various studies on
Spring Creek and the Sacramento River associated with toxic
acid mine waste. Ac~ording to DFG, the documented fishkills
listed in the Feasibility Study Report at locations below
Shasta Dam are directly attributed to mining operations at
Iron Mountain on the basis of actual observations of dead
25

-------
fish iI?-. the:rive~.,. inspections--of- the..acid.mine..was.te.,. .. .
streams, and water analyses for metals in the river, both
above and below the area influenced by Iron Mountain as well
as in Spring Creek. The occurrence of at least 30 fishkills
in the last 40 years on an irregular basis is due to varia-
tions in hydrologic events controlling the ratio of toxic
acid mine wastes to clean river waters released from Shasta
Dam.
COMMENT 3-3 (BOYER)
The following are statements or questions by Mr. Boyer to be
addressed in this section:
Is there any spawning area above Redding (i.e., between
Shasta Dam or Keswick Dam and Redding)?
.-.
When the Dept. of Fish and Game recently did fish auto-
psies, they found one fish that was in perfectly good
health with 4 ppm of cadmium in its liver.
. The decline in anadromous fishes was particularly notice-
able after the Shasta and Keswick dams were built. .

If Iron Mountain Mines, Inc. through Spring Creek is
killing 72% of the fish in the river, .please explain, .
on this basis, the anadromous fish run for 1984. Accord-
ing to Fish & Game and Sacramento Valley River Water
Users Association, the runs have increased steadily, at
least since 1982. 1984 has been the best run in a
decade.
.California Fish and Game have made major biological and
chemical errors in their toxicity tests because they
did not considercoprecipitation of copper, zinc and
cadmium with iron and aluminum. Although they proved
that zinc and copper are synergistic in intoxication
properties. They perhaps did not realize that almost
all the copper is precipitated at pH 6 and that zinc is
antagonistic to the formation of cadmium thionen, and
this will protect the organism from the toxic' effects
of cadmium.. Furthermore, copper is capable of displac-
ing both zinc and cadmium from metalothionen; thus cop-
'per can be taken up by lysosomes from which copper is
excreted to the bile.
Also, according to the National Research Council, sele-
nium will protect organisms from the toxic effects of
cadmium. In fact, the biologist who performed the toxic
test on Keswick fish perhaps doesn't realize that there
is biological interaction, both positive/negative, com-
petitive, synergistic as well as antagonistic among 25
elements, 16 of which are definitely essential to life;
5 of them definitely unnecessary for life; 4 of these
26

-------
. 0:" ~
, .
a~e toxic at relatively low levels that influence the
tolerance of ca~ium (also from the National Research
Council) .
With these facts of life...it is hard for me to believe
that all factors of. toxicology and biochemistry were
considered for- the fish toxicology tests, and that sub-
sequently the data that went into the computer program.
Please also remember that Mr. Pedri claims that cadmium
containing fish are the highest in the state at Keswick-
Redding area. When he was questioned about the San
Lorenzo River in Santa Cruz County, he said that it was
high too. Perhaps if more tests were made, he would
find that Keswick-Redding was not the highest in the
state.' .
.'::0.....
Mr. Boyer also had concerns regarding laboratory analyses
results and stated that data used in the computer analyses.
for comparing alternatives were based on these analyses and
therefore in error. These concerns are discussed in
Category 2 of this Responsiveness Summary.
RESPONSE TO COMMENT 3-3
There are spawning areas between Keswick Dam and Redding.
Tissue Contamination
The State Water Resources Control Board has been monitoring
body burdens in fish collected in waters throughout the
state since 1976. At the Sacramento River station at Kes-
wick, metals detected in rainbow trout tissues are at values
that represent a significant elevated toxic pollutant level
compared to all the other stations in the state. These ele-
vated metal residues include cadmium, silver, chromium, cop-
per, nickel, and zinc. There is' a limited amount of know-
ledge concerning the biological effects of these body bur-
dens with the exception of cadmium, where long-term exposure
and bioaccumulation studies have been reported in the liter-
ature~ The concentration of 4 ppm found in trout livers
. f-rom the. Kesw.ick-.station..exceeds-..the .value.s rep-Orted. -to__.r.ep~---.
resent detrimental exposure to cadmium.
. - -- -. .w .. ~
King Salmon Run in 1984

King' s~lmon have a complex life cycle that includes resi-
dence in the Sacramento River for approximately 3 or 4 months
up to the juvenile life stage with a return to the natural
stream as a spawning adult 3 or 4 years later. Factors that
influence the relative success of this year1s class of sal-
mon include, most importantly, the end of the El Nino cur-
rent in the northern Pacific Ocean and also good streamflow
conditions for these fish during the period they were juve-
niles in the river.
1"'

-------
Iron R.emoval in Toxicity Studies _.~',--'------

DFG's toxicity tests "essentially simulated the events in the
river. When acid mine waste is discharged into Keswick
Lake, precipitation of metals begins. The metals precipi-
tate at different rates and at different p~ levels. Iron
and aluminum are the first to come out of solution followed
by copper, zinc, "and cadmium. In terms of what metals are
available to cause toxicity problems for salmon and steel-
head below Keswick Dam, only copper, zinc, and cadmium
remain in the dissolved form at toxic concentrations. This
conclusion was supported by actual chemical measurements of
river water for both total and dissolved metals. Because
migratory fish cannot get above Keswick Dam, and aluminum
and iron precipitates essentially do not occur in signifi-
cant amounts bel-ow the dam, the smothering effect that these
precipitates have on eggs does not present a risk to wild
salmon and steelhead. However, the precipitates would pre-
sent a risk to eggs in a bioassay experiment.
Fish Physiology

The discussion of fish physiology with respect to what,
happens to metals once they are inside the fish is unclear. -
Fish physiologists have postulated a number of mechanisms
that allow fish to either eliminate metals from their body
or sequester them in parts of their body where they do less
harm. More importantly, physiologists have identified a
number of different fish tissues directly damaged by
exposures to copper, zinc, and cadmium. Therefore, damage
can occur during exposure to concentrations less than those
that cause death.
COMMENT 3-4 (Davy McKee-Morgan)

Appendix G of the report contains a description of a water
quality modeling effort. This model is utilized by the EPA
to compare the effectiveness of the various alternatives.
The report as published gives few details as to the actual
preexisting tests that were performed that were used-as
input to the model. Not having the original report, I would
like to question how these fish bioassays were conducted..
There is evidence in the recent literature which supports
the contention that all stages of fish from ichthyoplankton
to the adult stages that have been raised in waters contain-
in~me~als offer a 'greater resistance to these metals than'
do similar stages of the same fish species grown in waters
not containing these metals. Thus, it is important to uti-
lize fish species that have been grown in waters containing
metals if valid results are to be obtained. There has been
a decent fishery in the Sacramento River and its tributaries
all during the 125 years that this mine has operated, and
the greatest impact to these fisheries has been the artifi-
cal structures constructed in these streams by the Bureau of
Reclamation.
2ft

-------
RESPONSE TO COMMENT: '3- 4, '
,1:,' ,.'.
'. . . <
An acclimation phenomena has been observed with certain
stocks of fish challenged with zinc. These test results
indicate that these particular fish can tolerate slightly
higher zinc concentrations at a reduced mortality rate. To
account for acclimation as much as possible, DFG ~hose a
salmon stock native -to the upper Sacramento River as the
test species for the onsite toxicity tests using Spring
Creek waters. These onsite results confirmed the applica-
bility of laboratory results. .
The acclimation phenomena seems to be dependent on fish
receiving consistent exposure of zinc, through preceding
life stages. This can also selectively kill the more
sensitive individuals. Consistent exposure to metals does
not always occur~~'in the Sacramento River below Spring Creek
throughout the main fish development period (fall and win-
ter) and during all years. Because the discharge of larger
quantities of acid mine waste is irregular, instances occur
when eggs are not exposed to chronic concentrations of
metals in the fall but unacclimated fry are exposed to
metals during the winter. Additionally, there are some
generations tha~ return as adults that did not experience
significant exposure to metals as juveniles due to either a
favorable series of hydrologic events that occurred during
their stay in the river as juveniles or the fact that they
may have resided at a tributary or a hatchery as juveniles.
There has been a consistent long-term declining trend in the
upper Sacramento River king salmon and steelhead popula-
tions, especially in the 26-mile reach between Keswick Dam
and ~alls Ferry where documented toxic concentrations of
metals occur.
COMMENT 3-5 (IMMI-Foster)
The report also cites fish kills as another problem. This
assertion is based on a computer model projection by the
Regional Water Quality Control Board and the California
Department of Fish and Game. However, the model included
erroneous criteria, including the assumption that there are
spawning beds between Keswick Dam and the City of Redding'.
There', is one small riffle above the dam, but the 5 or 6
miles below Keswick Dam do not have any spawning beds'
remaining. Yet, that area was used in the model and
supposedly represents where fish were killed. In addition,
of the documented fish kills that are attributed to acid
mine drainage from IMM, only three were at the mouth of
Spring Creek. The other 30 documented kills were in Shasta
Lake, quite a ways upriver from Spring Creek. .
29

-------
RESPONSE TO COMMENT 3-5
Significant kingsaimon spawning beds exist between Keswick
Dam and the City of Redding along with excellent rainbow
trout habitat. DFG makes annual estimates of the king
salmon spawning stocks i~ this area.
The statement that the list of fishkills presented in the
Feasibility Study Report includes three kills below Shasta
Dam and ~O above Shasta Dam is incorrect. The correct tally
of the list referred to is 31 kills below Shasta Dam and one
kill above Shasta Dam.
COMMENT 3-6 (IMMI-Arman)
IMMI is aware ot,most, if not all, of the toxicity studies
conducted at Spring Creek regarding fish health and is also
well aware of the inadequacies of those tests and their
inconclusive results. The EPA studies admittedly were not
conducted on the Sacramento River and it is not known under
what conditions they were taken, nor is it known how such
unrelated studies can be used as a basis for proposing wate~
quality criteria for protection of, aquatic life in the
Sacramento River.
It is very probable that wherever the'EPA studies were con-
ducted, there was not the same natural buffering action that
is present in the Sacramento River.
RESPONSE TO COMMENT 3-6
In reports describing metal toxicity test results, such as
those presented by EPA; the constituents in dilution water
that affect metal toxicity are always reported. The
criteria chosen for the Sacramento River water take into
account the presence of constituents that affect metal
toxicity. .
The pH of the river is an important factor affected by the
acid mine waste. Although the river has buffering capacity
when it leaves Shasta Lake, the river pH is at times signif-
icantly depressed when limited dilution water availability
yields a higher ratio of acid Spring Creek water to river
water. The depression of the river pH decreases the pre-
cipitation rate of the metals and increases toxicity. One
example was during the 1969 fishkill when the river pH at
Redding actually dropped as low as 5.7. .

It should be recognized that the actual process of detox-
ification by precipitation of metals in the river is not
instantaneous. Precipitation occurs over time and distance
as the waste moves down the river with different metals
undergoing different rates of precipitation. Actual mea-
surements of river water during spill episodes at Spring
30

-------
Creek ~how that dis~olved' metai concentrations' in the 'cri-
tical range . for- s'alnion-- and'steelhead . can'- exist.. as' fa.r dowri.;.'-"", . ,
stream as Balls Ferry,' a river reach of approximately
26 miles. Below that area a combination of dilution and
precipitation generally reduces the dissolved .concentrations
to non-critical levels.
" .
COMMENT 3-7 (Katzakian)
The report appears to be well written, but contains numerous
inconsistencies and errors in the data tables. The first of
these is the fish kill table presented on pages 3 and 4 of
Chapter 3. I do not understand how fish kills in Shasta
Lake and at the base of the Dam relate to acid mine drainage
from Iron Mountain Mine, since any drainage from the mine
takes place well downriver from these sites. Also, the
table indicates'~~hat fish kills at Redding, where extensive
dilution has taken place, are not significantly different
than fish kills observed much closer to the mine in Spring
Creek and Keswick Reservoir, where higher heavy metal con-
centrations are observed. In addition, there is no informa-
tion as to the cause of the fish kills and whether or not
ani significant fish kills take place during the la~e spring,
summer and early fall months. "Also, for a large percentage
of the observed fish kills, there either is no estimate of
the number killed or no identification of the species
killed~ Based on the data in this table, I fail to see its
relevance to this report. .
RESPONSE TO COMMENT 3-7
The one fishkill listed as occurring in Shasta Lake has
nothing to do with discharges from Iron Mountain Mine via
Spring Creek. It was listed because the table was taken in
its entirety from another reference as shown on the bottom
of the table. There were four other fishkills listed as
"Below Shasta Dam." These have not yet been verified as to
whether or not they were below the influence of Iron Moun-
tain Mine discharges (Spring Creek). It doesn't necessarily
mean that they occurred at the base of Shasta Dam.

The remaining 27 occurrences of fishkills presented in th~
table are at locations affected by Iron Mountain Mine
releases.
Documented fishkills are also discussed in the Response to
Comment 3-2.
COMMENT 3-8 (Miller)
The Corps of Engineers is considering some riprap work on
the river below the diversion dam. The Department of Fish
and Game has stated that riprap deprives the sands and
gravels needed for spawning in that portion of the river to
31

-------
the p~int where 85"percent-'o-f ,the 'spawning fi'5h"'8.re:killed."
How does this mortality rate relate to the 72 percent fish
mortality rate assumed for the IMM no-action alternative?
RESPONSE TO COMMENT 3-8
This proposed riprap project does not relate to the Iron
Mountain Mine issu~. A geological study conducted by the
Department of Water Resources concluded that the riprap
project would reduce the available spawning gravels in the
project area by 85 percent.
COMMENT 3-9 (Shasta Cascade)
Is ~here-any record of the number of fish fry that have .been
endangered and/or killed by pollution problems? Has there
been a dollar value placed on the loss of this resource?
RESPONSE TO COMMENT 3-9
The only composite information found during the Feasibility
Study on fishkills resulting from pollution problems is the
table shown in Chapter 3 of the Feasibility Study Report. .

The U.S. Fish and Wildlife Service estimates a dollar value-
in their comments in Appendix B of this Responsiveness
Summary.
32

-------
CATEGORY 4--ENVIRONMENTAL AND PUBLIC HEALTH HAZARDS
Comment 4-1 is a general summary of comments and questions
that 'were received concerning public health and environmen-
tal hazards. A general response is provided by EPA under
Response 4-1. Specific comments and responses are then pre-
sented. Responses to Comments 4-2 through 4-9 are provided
by EPA. Responses to Comments 4-10 through 41.25are.provid-
ed by the California Department of Health Services, Epide-
miological Studies and Surveillance Section.
GENERAL COMMENTS AND EPA RESPONSE
COMMENT 4-1
Seven cominenters'-"-'(Boyer, Davy McKee, IMMI-Foster, IMMI-Arman,
McLean, Miller, Stauffer} commented that while the Feasibil-
ity Study Report discusses potential public health and envi-
ronmental hazards associated with acid mine drainage from
Iron Mountain Mine, actual risks are not proven and cannot
be used as justification for placing Iron Mountain Mine on
the National Priorities List or for requiring mitigative
action. The Feasibility Study Report in fact concludes that
the potential problems of dermal contact, ingestion of con- -
taminated water, and ingestion of contaminated fish are insig-
nificant or present no public health hazard. The potential
of fishkills in the Sacramento River as shown in the Feasibil-
ity Study Report is based on incomplete and misleading data.
The Feasibility Study was continued at considerable. expense
to develop alternative solutions to problems that were shown
not to exist. .
RESPONSE TO COMMENT 4-1
The objective of the public health and environmental assess-
ment presented in the Feasibility Study Report is to assess,
based on the no-action alternative, potential risks associ-
ated with acid mine drainage both at its source and migrat-
ing from the site. Under the no-action alternative, it is
assumed no remedial actions would be implemented to correct
the problems, and future land use could change. Potential
remedial action alternatives were identified, developed and
evaluated because releases of AMD fromIMM have impaired
water q~alityand aquatic life for a significant period of
time. These impacts have been documented and continue to
pose a significant potential threat to the environment.
The information presented in the Feasibility Study Report is
primarily based on data developed during the Remedial Inves-
tigation. Both investigations, the Remedial Investigation
and the Feasibility Study, are conducted after a site has
been placed on the National Prio~ities List (NPL). The
33

-------
. '.
place~~nt of a site on the NPL is based on a hazard ranking
system evaluation wh~ch is prepared prior to the Remedial
Investigation and Feasibility Study.. Therefore, comments
regarding the hazard ranking system and placement of the
site on the NPL have no relevance to the Feasibility Study.
If, however, the no-acti~n alternative is selected by EPA
subsequent to the Feasibility Study, then the site is
removed from the. NPL.
Public Health
Three types of exposure to acid mine drainage were discussed
in the Feasibility Study Report:
o
o
o
Dermal .contact with acid mine drainage (AMD)
Ingestion of waters affected by AMD
Ingestion of fish affected by AMD
Dermal Contact. As stated in the DOHS Endangerment Assess-
ment (AppendixB of the Feasibility Study Report), "direct
human exposure will probably be rare because of the
remoteness of the area." This is based on the current land.
use. However, land use could change in the future where
human exposure. could be more likely. In fact, Iron Mountain
Mines, Inc., in a letter to the Governor of California dated
August 13, 1985, stated objectives for the site that include
a private wildlife and game preserve and the development of
an exclusive subdivision surrounded by a private recreation'
park. .
Dermal contact under the no-action alternative represents
the greatest health hazard with respect to the other two
types of exposure (ingestion of water or ingestion of con-
taminated fish). At the Richmond portal, the AMD contains
sulfuric acid in concentrations (pH = 0.6 to 1.4) that could
cause serious eye injuries and skin irritation through
direct exposure (according to DOHS). The sulfuric acid is
accessible to direct human contact at the portal, in the
flume conveyinqAMD to the Boulder Cementation Plant, and at
the Boulder Cementation Plant. .
The AMD is diluted as it enters Boulder Creek, Slickrock
Creek, and Spring Creek, and there is less risk with regard
to dermal contact in these areas. The pH in Boulder Creek
was measured to range from 1.8 to 2.3 and for Slickrock Creek
wa~ measured to range from 2.8 to 2.9. Measured pH values
for lower Spring Creek ranged from 2.4 to 3.2.

Ingestion of Contaminated Water. Potential ingestion of
contaminated water from the Iron Mountain Mine site was dis-
cussed in the Feasibility Study Report for two different
areas--the upper study area (at the source, Boulder Creek, .
Slickrock Creek, Spring Creek, or Spring Creek Reservoir)
34

-------
\ I'
'''' :.',. '!.'
'. ,
and at. the City of Redding municipal drinking water supply
intake.
The potential for ingestion of AMD in the upper study area
under the existing land use is considered small because of
the remote location,and it would be unlikely that anyone
would willfully drink water that is discolored or has an
odor associated with it. However, the contaminated water is
accessible both on IMMI property and on other property along
Spring Creek. The potential for this exposure could change
with future land use changes. .
The potential for ingesting contaminated water from the City
of Redding water supply is also discussed in the Feasibility
Study Report. This could occur if domestic drinking water
standards for cadmium are exceeded in 'the City of. Redding
water supply. Even though there are no known measured con-'
centrations of cadmium exceeding these limits at the city's
raw water intake, they could be exceeded during periods where
discharges from Spring Creek are uncontrolled while releases
of dilution water from Shasta Dam are reduced for flood con-
trql purposes.
The limits would have to be exceeded regularly for this to
pose a significant public health threat.
Ingestion of Fish. Ingestion of fish taken from Keswick
Reservoir does not appear to represent a significant public
health threat as discussed in the Feasibility Study Report.
This was based on an analysis that expanded the analysis
prepared by DOHS in its endangerment assessment (Appendix B
of the Feasibility Study Report). The discussion in the
main body of the Feasibility Study Report compared metal
concentrations from eating fish in Keswick for one year
using the same scenario as, DOHS to values for the.- normal ' ._~-'~...;--
dietary intake. The difference in the analyses is that the
one in the text is based on metals measured in fish flesh
whereas the one prepared by DOHS is based on metals measured
in fish livers. The reference material in Appendix B. is
included in its original form as is all other reference
material received from authors other than EPA's contractor.
Public Health Summary. As discussed above, dermal contact
represents the greatest public health hazard with respect to
the other types of exposure mentioned above. Exposure to
sul~uric acid under current conditions is not the same with
respect to exposure during the period of active mining and
could change based on future land use. Exposure to AMD at a
pH ranging from 2 to 4 is not the same as potential exposure
to AMD at 0.5 to 1.0. Several attempts were made to obtain
all pertinent information from the Iron Mountain Mine files.
However, no health and safety records were provided for the
period of active mining.
35

-------
In conclusion, the public health issues are not the critical
factors in deciding what remedial action alternatives will
be selected by EPA. Instead the comparison of alternatives
is primarily based on meeting the selected cleanup objectives
in the Sacramento River below Keswick Dam, thereby,minimizing
the endangerment to the en~ironment presented by the AMD.
The public health issues also have little effect on the over-
all cost associated-with any of the remedial action
alternatives. '
Environmental Concerns
The environmental concerns for the Iron Mountain Mine site
are based on the effects of AMD migrating from the site on
aquatic life. The effects on aquatic life that are docu-
mented in the Fe~sibility Study Report are the following:
. 0
.--.---
l~-.
o
The continued flow of AMD has caused portions of
Slickrock Creek, Boulder Creek, and Spring Creek
to be essentially devoid of aquatic life.

Records for the fishkills listed in the Feasibil-
ity Study Report were, taken from a USGS report.
The table in'the Feasibility Study Report docu-
ments'a reference for each fishkill. This infor-
mation for 1940, 1944, 1948, and 1949 did not
establish the exact location of the reported fish-
kills below Shasta Dam. According to the Cali-
fornia Department of Fish and Game, with the
exception of these 5 years, all other fishkills
listed are attributed to the AMD migrating from
the Iron Mountain Mine site.
o
In addition to fishkills, the AMD being discharged
ha~ physiological effects on fish and also depresse~
the overall productivity of the river according to
the California Department of Fish and Game.
o
Additional information regarding environmental
concerns is provided by the U.S. Fish and Wildlife
Service in Appendix B.
EPA RESPONSE TO SPECIFIC COMMENTS
COMMENT 4-2 (McLean)
Since no factual evidence has been produced in the study to
show that there is any threat to human health, why is the
IMM site retained pn the NPL as a major "abandoned" mine and
threat to the public health?
RESPONSE TO COMMENT 4-2
According to the National Contingency Plan, Section 300.66(7),
"Sites may be deleted from the NPL when no further response
36

-------
is app~opriate. In deleting sites, the Agency will consider
whether any of the fo~lowing criteria have been met... (c)
based on a remedial investigation, EPA has determined that
the release poses no significant threat to public health or
the environment, and therefore, taking of remedial measures
is not appropriate at tha~ ,time.",

Based on the info.rmation obtained during the Remedial Inves-
tigation, the IMM site did not meet the above criteria for
removal from the NPL. For example, documented fish kills
resulting from discharges from the IMM site are an obvious
significant threat to the environment.
COMMENT 4-3 (McLean)
For the same re~.ons cited above (Comment 4-2), what is the
validity of the reason given for rejecting the IMMI proposal,
which states "there would be a risk to the public health..."
(page ES-9 in the Executive Summary, paragraph 1)?
RESPONSE TO COMMENT 4-3
It has not been demonstrated that the IMMI proposal can
attain applicable, relevant, and, appropriate federal and
state requirements. It is therefore not a complete pro-
posal. The risk is associated with continuing impacts to
the environment and aquatic life and potential impacts at
the City of Redding water supply intake while the project is
being developed and IMMI seeks to secure funding for the
project. Also, bioaccumulation of metals in both humans and
fish would continue to present risks. EPA does not want to
increase any existing or potential risks by not responding
as mandated under CERCLA.
'h'COMMEN,!,,"h4-4 (McLean)
Why has the historical record of public exposure to AMD
waters in Pennsylvania, West Virginia, and the IMMI Redding
area not been considered and discussed in the report?
RESPONSE TO COMMENT 4-4
Potential public health threats are based on site-specific
exposure routes and characteristics of the contaminants.
Exposure during active mining of the site is not necessarily
the:same as potential exposure during the current or poten-
tial future land use conditions.
COMMENT 4-5 (McLean)
Since the potential threat to human health is essentially
zero, and none of the sporadic fishkills in the Sacramento
River are totally attributable to the AMD discharge from
37

-------
IMM, wpat is the justification for the rush t~ spend $5 to
$140 million at this .site when there are dozens of more dan-
gerous sites throughout California and the nation to which
these funds could be applied for greater public protection?
RESPONSE TO COMMENT 4-5
Iron Mountain Mine is the State of California's worst water
quality problem associated with releases from mining sites.
The RWQCB has estimated that IMM carries an average of 2,350
pounds/day of zinc, 300 pounds/day of copper, and 50 pounds/
day of cadmium into the Sacramento River. In our investiga-
tion, we found that under relatively dry water conditions,
IMM contributed a minimum of 623 and up to 3,328 pounds/day
of heavy metals into the Sacramento River. We have docu-
mented that releases of AMD from IMM have severely degraded
water quality and resulted in fishkills directly attribut-
able to the site.
EPA and the State are proceeding in a manner designed to
ensure that the environmental conditions resulting in .
releases from IMM are responded to in a timely and efficient
manner. The funds that have been expended at IMM to date
have not directly precluded remedial response action at
other toxic waste sites in California.
COMMENT 4-6 (McLean)
Since the only real threat of AMD is sporadic fishkills,
these. could be compensated for by building new fish hatchery
facilities at a very nominal cost. Why was this simple
alternative not considered? .
RESPONSE TO COMMENT 4-6
The objectives of every
and minimize threats to
public health, welfare,
in 40 CFR 300.68(j).
remedial action are to "...mitigate
and provide adequate protection of
and the environment...n as specified
Building a fish hatchery to replace fish being killed by
releases from the IMM site was not considered because it .
would not address the underlying environmental problem and
would not, therefore, meet the objectives of
40 CFR 300.68(j).
.. .
The California Department of Fish.and Game's position is
that it is not appropriate to compensate for the losses to
one of the aquatic resources destroyed by pollution by
engaging in expensive hatchery production. CDFG has
informed EPA that it considers the most appropriate action
to be protection of all the affected resources by imple-
menting remedial actions at the Iron Mountain Mine site.
].tj

-------
,.
Additionally, CDFG believes that the angling public should
not be asked to abandon the use of a river section because
of an improperly controlled toxic was.te stream. EPA' agrees.
COMMENT 4-7 (McLean)
Why is there no mention of the fact that the original rank-
ing evaluation was incorrect and that a true reranking may
completely eliminate IMM.as a candidate for Superfund expen-
ditures? Mr. Jack W. McGraw, Assistant Administrator, EPA,
in his letter .of 2/5/85 to IMMI indicated that this would be
part of the evaluation procedure.
RESPONSE TO COMMENT 4-7
The hazard rankihg score, based on the best available infor-
mation, was accurate. The EPA has apprised IMMI through
numerous pieces of correspondence that the agency has
reviewed the HRS scoring of IMM and has concluded that the
findings of the Remedial Investigation, when factored into a
rer~nking of the site, would cause the site to receive an
HRS score sufficiently high to remain on the NPL.
COMMENT 4-8
(Air)
The lime/limestone water treatment plan has potential air
impacts relating to release of these five toxic metals. Our
concern focuses on the aeration process to convert ferrous'
to ferric iron. Aeration presents the possibility for
entrainment of particulate matter in exhaust gases.

If this method of remediation is chosen, the EIR should give
sufficient information about the process and plant for the
air pollution control district and the ARB to determine the
need for emissions control and appropriate technology to
achieve it. .
RESPONSE TO COMMENT 4-8
The aeration system which would be used in the lime/
limestone treatment process is not expected to entrain
particulate matter in the exhaust gases. If a lime/
limestone treatment process is chosen as a remedial action,
and if an EIR is required, the necessary information will be
pro~ideQ to the ARB.
COMMENT 4-9. (Agriculture)

The feasibility study states that the continual discharge of
heavy metals into the Sacramento River has exceeded lethal
concentrations for aquatic life and will continue to do so
unless remedial action is implemented at the Iron Mountain
Mine. Thi~ acid mine drainage has the potential of impair-
ing agricultural yields as well since the contaminated
39

-------
Sacramento River water serves as irrigation water for
agricultural lands. -
RESPONSE TO COMMENT 4-9
There is a potential for improving agricultural yields,
however, it appears to be unlikely since drinking water
standards have never been exceeded in the Sacramento River
near Redding. In addition, metals concentrations in the
Sacramento River -are lower during the irriga-tion season.
DOHS RESPONSE TO SPECIFIC COMMENTS
INTRODUCTION
In August 1984, the Epidemiological Studies and Surveillance
Section (ESSS) responded to a request by Mark Galloway of
the Toxic Substa~ces Control Division to provide an endan-
germent assessment for the Iron Mountain Mine site in Shasta -
County. The assessment was based on data provided by the
Environmental Protection Agency (EPA) contractor CH2M HILL.
This endangerment assessment was subsequently incorporated
into the Feasibility Study at the site prepared by CH2M HILL.
Public comments on the Feasibility Study were received by ,
ESSS in September 1985, and responses to comments related to
the endangerment assessment were prepared as presented
below. -
Several comments were based on the recalculation of health
risk from consumption of cadmium-contaminated fish. The
Department of Health Services (DOHS) assessment was based on
a table of fish "tissue" cadmium levels provided by CH2M HILL.
Subsequently, in the Feasibility Study, these tissue levels -
were identified as liver levels and risk was recalculated on
the basis of fish muscle levels not made available at the
time of the DOBS assessment.
Because the Iron Mountain site is not located in a population
center, as is the case with many other hazardous waste sites,
the environmental aspects of the endangerment assessment
would appear to form the driving force for remediation.
COMMENT 4-10 (Davy McKee-Morgan)

Water'downstream from the cementation plants is-essentially
similar to recreational water in other areas of Shasta coun-
ty and no incidences of eye or skin damage have been report-
ed. Contact with individuals in Pennsylvania indicates that
no eye or skin damage has resulted from acid mine drainage
in that state.
40

-------
RESPONSE TO COMMENT ,4-10
. .:~ . :'t' .', ,I' . t.
Scientific studies in humans demonstrate that eye contact
with acid (hydrochloric) with pH values below 4.5 leads to
irritation, while values from 3.5 to 4.5 produces reversible
corneal damage. Water samples from streams in the area were
documented with lower pH. ranges of 2.2 to 3.6. This pro-
vides a basis for potential health hazards. .
COMMENT 4-11 (Davy McKee-Morgan)

Metal content of fish filets rather than fish liver should
be used as the basis of estimating human exposure via sport
fish consumption.
RESPONSE TO COMMENT 4-11
.-'
Fish muscle data from 10 trout caught below Keswick dam in
1979-1980 are available and have been used for a revised
estimate. This revised estimate was made subsequent to the
August 1985 .Public Comment FS. While risk of eating fish is
reduced in the revised estimate, the long-term risk from
thi's bioaccumulative toxin must not be underestimated.
Without remediation, mine effluent will continue to be
deposited in sport fishing areas of the Sacramento River.
The concentration of cadmium in fish will continue to rise
and health risk will increase. More complete and current
data on cadmium in the Sacramento River ecosystem are needed
to adequately predict this increase in health risk.
COMMENT 4-12 (Davy McKee-Morgan)
Comparison of stream water with drinking water standards is
not relevant because the standards are applied after munici-
pal water treatment.
RESPONSE TO COMMENT 4-12
Comparison with drinking water standards is'provided because
these are the most highly standardized reference values.
The endangerment assessment does not state or imply that the
drinking water quality has been compromised by effluent from
the Iron Mountain Site.
COMMENT 4-13 (Boyer)
The chance of humans being injured by acid mine drainage is
remote as the access is limited by permission of the prop-
erty owner.
41

-------
RESPONSE TO COMMENT 4-13
Human exposure cannot be excluded given the relative proxi-
mity of a population center and the recreational use of sur-
rounding areas. Any .unfenced area must be considered to
permit unlimited public ac~ess.
COMMENT 4-14 (Boxer)
Ingestion of harmful amounts of toxic levels of the elements
is remote if indeed non-existent. The feasibility study of
CH2M HILL says so.
RESPONSE TO COMMENT 4-14
Again, the potential for damage to public health via inges-
tion of metals exists and has been quantified on the basis
of available information.
COMMENT 4-15 (Boyer)
Ingestion of fish from the Sacramento River by humans is
benign as far as toxic levels of cadmium, copper, or zinc
are concerned, because if the fish do accumulate these met-
als, it is in the liver. .
RESPONSE TO COMMENT 4-15
The highest tissue levels of cadmium are found in the liver,
but all tissues are affected by a heavy body burden of th~s
metal. It is estimated that 50 percent of the body burden
of cadmium is located in the liver and kidney, with another
50. percent distributed across other tissues. Unfortunately,
people also accumulate cadmium in the liver (and kidney)
over their lifetime. Accumulation of metals in these organs
is a response to elevated exposures and indicates that the
organism is at risk for biological effects of these agents.
While copper and zinc are essential trace elements, they are
both toxic at high exposures and lower exposures can lead to
disruption of metabolic processes involving these metals as
well as calcium and iron. .
COMMENT 4-16 (Boyer)
In TOXICOLOGY, a book by Casarett, Ph.D., and Doull, M.D.
and.. Ph.-D., (McMillen 1975), the normal urinary levels of
cadmium in the U.S. range from .5 to .11 mcg. per liter.
wonder municipalities are concerned about meeting basin
standards. This book also states, on page 468, that in
1971, lithe levels (of cadmium) in milk from 61 American
cities were found to be 17 to 30 ppb." I am wondering if
Superfund money was spent to clear up this problem.
No
42

-------
. '.
Zinc is not only an essential,el~ment for life' and reproduc-
tion, ,but is antagonistic to the effects of cadmium. Zinc
is also a component of insulin as well as at least 25 essen-
tial enzymes and hormones. It is required in the syntheses
of DNA and the proper development and functioning of repro-
ductive organs.
RESPONSE TO COMMENT 4-16- '
The current edition (1980) of the text cited by Mr. Boyer
does not include reference to these cadmium concentrations
in milk. While zinc is an essential trace element, and is
biologically regulated, excess zinc ingestion interferes
with biological function of other trace elements, primarily
iron, copper, and selenium.
COMMENT 4-17 (Stauffer)
'~....
While there is a problem of heavy metal discharge... the
related dangers have been exaggerated.... There is no human
health hazard presented.... Statements such as "it is pos-
sible that the EPA Safe Drinking Water Act maximum contain-
ment level for cadmium could be exceeded at the City of,
Redding municipal water intake"... are very misleading'.
RESPONSE TO COMMENT 4-,17
One of the analyses of intake water at the plant yielded a
cadmium level at the safe drinking water maximUm. This sug-
gests that the range of values already overlaps the standard.
Care was taken in the endangerment assessment to avoid exag-
gerating the threat to municipal water in Redding.

COMMENT 4-18 (Stauffer)
The pH measurements on which the onsite possibility of eye
or skin irritation is based are not those of any water with
which the public contact is foreseeable, but rather those at
the drainage outfall of the Richmond portal. The study'
reveals no record of any injury toanyone...from the Iron
Mountain discharge waters.
RESPONSE TO COMMENT 4-18
The pH of water from streams in the area is in the irrita-
tiop range as detailed above. We did not study incidences
of injury, since our aim was to describe endangerment.
Prior injury is not a prerequisite for EPA action under
Superfund.
43

-------
COMMENT 4-19 (Stauffer)
Mineralized taste of .the stream water would be sufficient to
stop a theoretical trespasser from drinking enough of the
water to cause a problem.
RESPONSE TO COMMENT 4-19., '
Hopefully this' would be the case; however, we have no infor-
mation on the taste, color, or smell of the water.
COMMENT 4-20 (McLean)
IMM should be reranked on the basis of the new health effect
data in the report, which justifies the immediate removal of
IMM from the N~L as a first logical alternative. '
.-,
RESPONSE TO COMMENT 4-20
Endangerment assessment is part of the feasibility study of
an NPL site. It is 'not used to rank the site or place it on
the NPL list. Please also see the Response to Comment 4-2
above, and Comment 9-1 below.
COMMENT 4-21 (McLean)
Four human health threats were cited in the, "IMM Hazard
Ranking System evaluation." They were dismissed by the
(feasibility) study; these conclusions justify the immediate
removal of IMM from the NPL. '
RESPONSE TO COMMENT 4-21
The endangerment assessment prepared by DOHS has no bearing
ontbe original ranking of the site, as mentioned above.
Estimates of human health risk form only a portion of the
endangerment assessment, which also includes estimates of
risk of environmental damage. Please also see the Response
to Comment 4-2 above, and Comment 9-1 below.'
'COMMENT 4-22 (McLean)
Local stream water with pH of 2.0 to 4.5 is in the same range
as river waters in Pennsylvania and West Virginia where there
have been no recorded incidences of adverse effects on' eyes,
skin, or from ingestion. No incidences of adverse effect on
employees or visitors have been recorded in over 107 years
at the Iron Mountain site. .
RESPONSE TO COMMENT 4-22
Scientific reviews of epidemiology of health effects of acid
mine drainage (AMD) are needed to support this view. It
should be noted that a great deal of our information on the
44

-------
problem of cadmium toxicity in humans resulted from obser-
vations of a physician - in a -residential- community- downstream - --
from a mine that was ~ischarging cadmium. Thus, there is
certainly some precedent for concern over health effects
caused by mine effluents. In addition, prior injury is not
a prerequisite for EPA action under Superfund.
COMMENT 4-23 (McLean)
The report bases its justificati9n for recommending the
expenditure of millions on the "opinion" of an alleged State
Health expert that AMD is a potential contact threat to
human health.
RESPONSE TO COMMENT 4-23
The wording as -well as the content of the DOHS endangerment
assessment and also the Feasibility Study Report chapter on
health effects-makes it clear to what extent a health risk
is estimated to exist. This estimate is based on available
information and was not exaggerated. The evaluation was
appropriately prepared and has played an appropriate role in
the Feasibility Study-as a whole. A substantial and immi- -
nent threat to human life is not a major consideration-in
the sequence of events involved in EPA actions at this site;
COMMENT 4-24 (McLean)
A true professional evaluation of the AMD contact threat
should have contained a documented record of adverse health
effects incurred by AMD exposure in Pennsylvania, West Vir-
ginia, and Redding, as well as bio-assays of AMD contact
toxicity in animal models.
RESPONSE TO COMMENT 4-24
Epidemiological studies and animal assays are not an initial
step in public health risk assessment at hazardous waste
- sites.
COMMENT 4-25 (IMMI-Arman)
Possible health hazards because of Redding drinking water,
contact with AMD, or ingestion of sport fish are found by
the Feasibility Study to not represent any significant-
health-risk. Because of this, Iron Mountain Mines should be
removed from the NPL. -
RESPONSE TO COMMENT 4-25
The Feasibility Study and the DOHS endangerment assessment
are in substantial agreement as to the extent of human
health hazard. These assessments are part of the Feasibil-
ity Study and were not involved in the original ranking
process.
45

-------
CATEGORY 5--NEED FOR REMEDIAL ACTION
COMMENT 5-1 (Chico Flyfishers)

The Chico Flyfishers Club recognizes the high value of the
fishery supported by the 'Sacramento River, and even more
importantly, the ,value of the fishery once it reaches its
full potential when this dump is controlled. The Environ-
mental Protection Agency is to be commended on the cleanup
plan prepared for the waste site.
COMMENT 5-2 (CDFG)
This hazardous waste site releases the largest volume of
acid mine waste,~ffecting the greatest downstream area in
California. The metal-laden waste has been proven to cause
substantial damage to salmon and steelhead populations 'and
other aquatic life. We are pleased with the report's out-
line of alternative courses of action to protect the upper
Sacramento River from these toxins. Actions need to be
taken as soon as possible to correct the pollution problem. ,
COMMENT 5-3 (Shasta Cascade)
Salmon resources are a very important part of the area's
future economic prosperity. Whatever is necessary to remove
pollutants from the Sacramento River must be done. The en-
largement of the Spring Creek Reservoir would be a signifi-
cant step. We cannot delay any further in taking action.
COMMENT 5-4 (FWS)
The Fish and Wildlife Service is primarily concerned with
adverse impacts that acid mine drainage from Iron Mountain
Mine has on anadromous fish resources of the Sacramento
River. Limited fish and wildlife resources occur in the low-
er Spring Creek drainage, largely because of extensive land
disturbance, deveqetation, and the erosive character of
soils in this area. In.our opinion, the overall benefit of
sign{ficantly reducing or eliminating toxic discharge to the
Sacramento River will far outweigh the impacts of remedial
measures, whether they be major structural, source point,' or
water diversion related.
RE&PONSE TO COMMENTS 5-1, 5-2, 5-3, AND 5-4

EPA appreciates the support of the above commenters for the
need to proceed with remedial action.
46

-------
CATEGORY 6~-COSTS OF'REMEDIAL ACTION
..-
COMMENT 6-1 (IMMI-Foster)
The proposed alternatives would be a continuing cost for as
long as it continues to rain in the Redding area. They
would completely destroy all possibilities of mineral pro-
duction and income." Therefore, cost recovery would be
impossible, and .the taxpayer would ultimately be stuck with
the bill. .
RESPONSE TO COMMENT 6-1
Under the current Superfund legislation, EPA is responsible
for paying the O&M costs for the first year. The operation
and maintenance.~osts for the remaining years would be paid
for by the State of California. -

EPA is confident that implementation of any agency-funded
remedial action would not preclude or present an unreason-
able barrier to future mining at the site. -
COMMENT 6-2 (McLean)
What is the det"inition of "cost-effectiveness" as it is used
for Superfund sites?
RESPONSE TO COMMENT 6-2
According to the definition in the NCP, cost-effectiveness
is defined as the lowest-cost alternative that effectively
minimizes threats to and adequately protects the public
health, welfare, and the environment. -
47

-------
CATEGORY 7--TIMEFRAME FOR IMPLEMENTING REMEDIAL ACTION
COMMENT 7-1 (Davy McKee-Turk)

EPA has stated that it would take a year for design and 2-3
year~ for construction of a lime neutralization facility.
Davy McKee's experience indicates that they could construct
this type of facility in 18 to 24 months, including the
design of the processing facilities.
RESPONSE TO COMMENT 7-1
At this time, EPA is not proceeding with lime/limestone
neutralization and would only do so if needed. The design
and construction of other component remedial action
alternatives wi~ actually be completed far in advance of
the estimates for the treatment works.
COMMENT 7-2 (Rardin)
Once action has been implemented, how long will it take to
clean up Iron Mountain? Is it likely that any of the
diversion dams would ever be removed in our lifetime?
RESPONSE TO COMMENT 7~2
Once a remedial action is implemented, the benefits to the
Sacramento River are expected to be immediate. Acid mine
drainage leaving the site, although reduced by implementing
various proposed alternatives, is expected to continue for
many years.
Should an alternative be selected that includes the con-
struction of surface water diversion structures, it is not
expected that these diversion structures would be removed in
our lifetime.
48

-------
CA1-EGORY 8--LIABILITY FOR IRON MOUNTAIN MINE PROBLEMS
COMMENT 8-1 (Collier)
Will IMMI have to pay for ~onstruction of the lime neu-
tralization plant?

How much liabiiity will government agencies have to assume
for contributing to the problem by the operation of Shasta
Dam and Keswick Dam? There should be more examination of
what the government has done to exacerbate the problem at
IMM.. .
RESPONSE TO COMMENT 8-1
Under the Comprehensive Environmental Response, Compensation,
and Liability Act (CERCLA), responsible parties are liable
to reimburse EPA for all costs expended in taking a response
action at an NPL site. This would include the cost of
constructing a lime neutralization facility, should it be
deemed necessary to meet cleanup objectives. Under CERCLA,
a responsible party is defined as the current owner or
operator of the. site, the past owner or operator, and per-
sons who generated or were involved in transport, treatment,
or disposal of hazardous substances at the site. IMMI, as
the current property owner, may be liable to reimburse EPA
for past response costs, and any costs expended by the
agency in implementing Combined Alternative CA-7.

The operation of the Shasta Dam, Keswick Dam,. and Spring
Creek Debris Dam has no real effect on discharges of AMD
that leave the IMM site. The IMM problem probably existed
long before the construction of these dams.
The USBR currently operates Spring Creek Debris Dam to
minimize the toxic effects of AMD from IMM on aquatic life
below Keswick Dam.
49

-------
CATEGORY 9--PLACEMENT OF IRON MOUNTAIN MINE ON THE NPL
COMMENT 9-1
...
Three cornmenters (IMMI-Arman, IMMI-Foster, McLean) stated
that Iron Mountain Mine was erroneously placed on the
National Priorities List (NPL) in the first place, due to
incorrect and misrepresented data. The following points
were made:
o
Flat Creek (the RWQCB's basis of groundwater rank-
ing) has only 6 residents, not 40.
o
There are no water wells in the Flat Creek drain-
age, anq the quality of water for all residents of
Flat ~eek meets all primary drinking water stan-
dards. .
o
Spring Creek does not and never has caused the
quality of the City of Redding's water supply from
the Sacramento River to exceed the EPA primary
drinking water standards even under the "worst
case" .conditions over the past 100 years.
o
There- is no factual evidence produced in the study
to show that IMM in its present state is any
threat to human health. It is no different from
any other normal copper mining operation meeting
prescribed effluent limitations, yet it was false-
ly classified as an "abandoned" hazardous waste
site. IMM should be re-ranked on the basis of the
new health effect data in the report which jus-
tifies the immediate removal o.f IMM from the NPL
as a first logical alternative.
RESPONSE TO COMMENT 9-1
Releases from IMM do not have to exceed drinking water stan-
dards at the water supply intake in order to be considered
as a candidate for the NPL. Evidence of release to the sur-
face water pathway (which is one of three pathways con-
sidered when evaluating a site for placement on the NPL) is
obta.ined when releases from a site are above background;
this has been documented by past State sampling and during
EP~'s Remedial Investigation. .

According to the National Contingency Plan, Section 300.66(7),
"Sites may be deleted from the NPL when no further response
is appropriate. In deleting sites the Agency will consider
whether any of the following criteria have been met... (c)
based on a remedial investigation, EPA has determined that
the release poses no significant threat to public health or
the environment, and therefore, taking of remedial measures
50

-------
, .
is not appropriate ?-t that ti~e.. ", Based on the information
derived during the 'Remedial Investigation, the Iron Mountain
Mine site did not meet the above criteria for removal from
the NPL.
The findings of EPA's Remedial Investigation that there is a
low potential for onsite,hurnan exposure to acid mine drain-
age (dermal contact and ingestion)has no bearing because
it is not considered in the hazard ranking scoring of a
site.
- COMMENT 9-2 (Miller)
There are many pollution sites in California that are in
more need 6f Superfund money than Iron Mountain Mine.
RESPONSE TO COMMENT 9-2
EPA believes that through the Federal Superfund program and
the State Superfund program administered by the Department.
of Health Services, priority toxic waste sites are receiving'
appropriate remedial and emergency response actions and are
being funded at appropriate levels. Funding the Iron Moun- .
tain Mine RIfFS has not directly precluded remedial response
actions at other priority sites. .
51

-------
CATEGORY 10--AVAILABILITY OF RI AND FS REPORTS/
.,...
PUBLIC COMMENT PERIOD
COMMENT 10-1
Three commenters (Davy McKee-Morgan, IMMI-Arman, Stauffer)
commented about difficulties in obtaining the Remedial
Investigation and Feasibility Study Reports for review and
about the inadequacy of the public comment period. The fol-
lowing comments were made:
o
Mr. Morgan stated that on August 2, 1985, he asked
EPA to send three copies of the Feasibility Study
Report to the Davy McKee Corporation for review.
They ~ceived one copy on August 9 and one on
August 12; one was sent by IMMI and one by CH2M
HILL. This allowed only a short time for Davy
McKee to review the report and prepare for the
August 15 public meeting.

Mr. Arman stated that 21 days is inadequate for
public comment on a project of this size. Even
thoug~ the Feasibility Study Report was completed -
for release on August 2, distribution was delayed
for several days. He believes the information
repository at the Redding public library never did
receive a copy of the report. This was a definite
disadvantage .to the public. . More time between the
public meeting and the close of the comment period
would have allowed a much more comprehensive and
detailed critique of the report. Additional time
for comment was requested from EPA, but this
request was refused.
o
o
Stauffer also commented that the 3-week comment
period is unreasonably short for such a complex
report. Typically, EPA provides for a comment
period of at least 60 days and often longer. Fur-
ther,it is EPA practice to provide for input from
interested parties prior to the publication of a
Feasibility Study Report. The National Contingen-
cy Plan provides that industry input should be .
solicited by the Technical Advisory Committee
(TAC) in the development of remedial options~ The
TAC did not include an industrial representative,
nor is Stauffer aware that any effort was made by
. the TAC to solicit industry views.
The shortness of the comment period was aggravated
by the fact that the Feasibility Study Report was
not released to Stauffer Chemical Company until
August 8 and could not be made available to tech-
nical staff until August 12.
52

-------
---------~~-...--------,;."--.--'-
.-.-
Stauffer ~tated its in~ention to submlt detailed
comments to EPA by.Se'ptember 30, 1985,and reques-
ted EPA to defer any decision on the selection of
a remedial option or the commitment of funds until
EPA reviews these comments.
Stauffer's effqrt to review th~ Feasibility Study
Report was also hindered because they did not have
the analytical data that were the basis for
establishing the remedial alternatives. They
requested the Remedial Investigation Report for
review on several occasions, but did not receive
it from EPA.
RESPONSE TO COMMENT 10-1
EPA is under no.~~bligation to provide copies of the Fea-
sibility Study Report to IMMI contractors; our responsibil-
ities were fulfilled in providing IMMI with its own copy.
We believe it. is IMMI' s responsibility to forward copies of
any reports it wants reviewed directly to its contractors. .
Nevertheless, EPA did provide IMMI and its contractors with
five copies. Copies were also available at two information
repositories in Redding (the public library and the RWQCB
offices) and at. EPA' s Region 9 office from August 2 through -
August 23 for review and comment by the public and inter-
ested parties. The availability of the report was announced
in newspaper notices 2 weeks before the beginning of the
public comment period and in a fact sheet distributed to the
project mailing list.
According to Section 300.67(d) of the NCP, the typical
tirneframe in the Superfund program for review of documents
is 3 weeks; EPA met that requirement. EPA believes the.
3-week public comment period was adequate to receive public
comment.
EPA did informally extend the review and comment period to
September 30, in part to consider Stauffer's comments. We
believe this decision demonstrated a good faith effort on
the part of EPA -to consider comments on the Feasibility
Study Report. Stauffer was encouraged to submit comments to
. --EPA close to -the- Augus-t- 23-.d-ate so - t-hey- could--be - cons-idered
prior to the selection of a remedial action. However, EPA
did not receive Stauffer's comments until October 9, almost
7 w~eks past the close of the public comment period.

The Feasibility Study Report was reviewed by a representa-
tive from Stauffer .at EPA's Region 9 office on August 6
or 7. The draft Remedial Investigation Report was available
for public review at the information repositories in Febru-
ary 1985, as stated in a fact sheet that was distributed to
the project mailing list. Two copies of the final RI report
53

-------
were made available to Stauffer, one to its San Francisco
office..'.and one to the President of Stauffer.
During the course of EPA's investigation, there appeared to
be no interest on the part of the potentially responsible
parties (PRPs) or industry groups regarding their participa-
tion in the Remedial Investigation/Feasibility Study. The
Technical Advisory Committee was composed of representatives
from Federal and 'state regulatory agencies, some of whom
have extensive experience with the mining industry and min-
ing-related matters'. Since there was no interest expressed
by the PRPs, EPA considered the availability of the draft RI
report and the 3-week public comment period for the draft FS
report as the principal means of securing industry's and the
PRPs' views on the RI/FS.
--.
54

-------
CATEGORY 11--TECHNICAL INPUT AND REVIEW OF THE RI/FS
COMMENT 11-1
Four commenters (Boyer, IMl1I-Arman, McLean, Miller) ques-
tioned the composition of the Technical Advisory Committee
(TAC), as follows: . .
0'
The National Contingency Plan provides that indus-
try input should be solicited by the TAC in the
development of remedial options. No effort was
made to solicit industry views or include an
industrial representative on the TAC. Why weren't
representatives from industry, economic develop-
ment,.pcilitics, or the general public included on
the TAC?
o
TheTAC included only representatives from govern-
ment agencies and appears to be a biased group
that has been blaming Iron Mountain Mine for all
the fish problems in the Sacramento River.
o
Is it. policy that only government agencies are
represented on technical advisory committees?
industry ever included?

The study should have been reviewed by recognized
technical experts in the fields of ana~ytical
chemistry, biology, computer programming, and acid
mine drainage abatement technology.
Is
o
RESPONSE TO COMMENT 11-1
It is not policy that only governmental agencies be repre-
sented on technical advisory committees. Industries have
been included on these committees. Industry input is .
encouraged, but not required. During the course of EPA's
investigation, interest was not expressed by, nor did EPA
perceive interes~ from, the PRPs, industry groups, or the
public regarding their participation in the Remedial Inves-
tigation/Feasibility Study. .

The TAC was composed of representatives from State and Fed-
eral agencies with expertise in critical areas that would
ensure that EPA had a full understanding of the environ-
mental problem at IMM and possible solutions to the problem.
The TAC served only in an advisory capacity to EPA and had
no decision~making power; all project decisions rested with
EPA in consultation with DeHS and RWQCB.
One technical committee of the TAC included a
processing expert and a mining waste expert.
was expanded to include a representative from
School of Mines Research Institute (CSMRI).
metallurgical
Later, the TAC
Colorado
55

-------
COMMENT 11-2
(Stauffer)
Orebody Capping
Throughout the report, EPA's contr~ctor suggests complete
capping of the site above the Richmond orebody at a cost of
$7.0 MM. Complete capping is unnecessary and impractical.
Instead, diversion of local surface drainage channels fr.om
above the pyrite deposits, closure of major mine openings
(including the Brick Flat pit) and filling of caved areas
and ground cracks should be undertaken.
These actions will result in a substantial reduction of near
vertical water infiltration to mine workings in three major
AMD source areas--Brick Flat, Richmond, and Hornet. This
selective closuE~ and diversion program can be accomplished
at an estimated cost of $2.5 MM and will accomplish essen-
tially all of the objectives of the capping remedy.
Combined Alternatives CA-5, 6, and 7 ignore the beneficial
effect of selective capping and rely entirely on reservoir
expansion and water diversion to meet cleanup objectives.
RESPONSE TO COMMENT 11-2
Based on the information obtained during the Remedial Inves-
tigation, complete capping is estimated to be much more
effective than partial capping and surface diversions. How-
ever, if a phased approach is taken, partial capping could
be implemented prior to complete capping to verify the
analyses in the Remedial Investigation. If partial capping
and diversion prove to be more effective than estimated,
complete capping may not be necessary.
COMMENT 11-3
( Stauffer)
Any groundwater intercept system at this site is expensive
and of questionable benefit. As indicated in later comments
on the Remedial Investigation Report, the extent of ground-
water contribution to downstream heavy metal levels has not
been clearly identified in the investigative report.'

Our analysis and that of CH2M HILL indicate that contamina-
tion of laterally moving groundwater is not a major contribu-
tor to site releases. Diversion of Slickrock Creek around
selected tailings areas will substantially reduce contamina-
tion measured in the upper Slickrock Cr~ek area at moderate
expense.
To include an expensive groundwater intercept system (at a
cost of $10.0 MM), with no assurance of its effectiveness or
need is not a cost-effective use of fund monies and is con-
trary to the direction of the NCP.
56

-------
--~-- --- -- - -~-----,------=--
t .
RESPONSE TO COMMENT .11-3
The Remedial Investigation indicated that limited data were
obtained during the RI and recommended further studies prior
to implementing the groundwater inter.cep.tion alternative _.

Results of the Remedial investigation indicate that approxi-
mately one-third. of' the average flow from the Richmond
portal is groundwater. The Richmond portal (see Figure 6-6
in RI) accounts. for 31 percent of the copper and 70 percent
of zinc and cadmium. Therefore, assuming metal load
reduction is proportional to the flow exiting the portal,
then .10 percent of the copper and 23 percent of both zinc
and cadmium of the overall metals leaving the site are due
to groundwater. . .
There is no information available to
effectiveness of diverting Slickrock
metal load reduction on Big Seep.
fully determine the
Creek with regard to
COMMENT 11-4
(Stauffer)
A major cost factor in Alternates CA-5, 6, and 7 is incl~-
sion of a substantial expansion of the holding capacity of
Spring Creek Reservoir.

We believe there is inadequate data available at the present
time to justify such an expansion. Diversion of upper Spring
Creek and Slickrock Creek, combined with selective plugging,
sealing, and water diversion in the immediate vicinity of
mine workings will sufficiently reduce the volume of water
collected at the Debris Dam that the present facility can be
utilized without expansiQn.
RESPONSE TO COMMENT 11-4
The data used in the model to evaluate alternatives that
include reservoir expansion are based on historic Spring
Creek Reservoir inflows and metal loadings and flow releases
from Shasta Dam. Using this information, the analyses in
the Feasibility Study indicate that the alternative iden-
tified in this conunent by Stauffer does not meet the cle~nup
objectives established by EPA.
COMMENT 11-5
(Stauffer)
Heavy Metal Removal

Treatment of collected water for removal of heavy metals,
other than the cementation process currently operated, is
impractical and unnecessary. It will most likely create a
hazardous waste disposal problem for disposal of the large
57

-------
volume of metal contaminated sludge generated by .the treat-
ment system (because of the RCRA mixture rule) which is
overlooked entirely in the report.
RESPONSE TO COMMENT 11-5
Treatment of collected water for removal of heavy metals
will create sludge which may be classified as a hazardous
waste. This does not necessarily mean that this treatment
technology is impractical and unnecessary. The disposal of
metals-laden sludge was considered with regard to RCRA
requirements in the report in the event RCRA is relevant
and/or applicable.
COMMENT 11-6
( Stauffer)
Five major sources (Richmond portal, Lawson portal, Old No.8
mine, Big Seep, and Brick Flat) are stated to account for'
72 percent of copper and 86 percent of zinc and cadmium leaving
the mine area. The scope of chemical analysis and sampling
from this investigation are ~ sufficient to be certain of
the.se proportions. It is likely that just three (Richmond,
Lawson, Old No.8 mine) of the cited sources account for
most of the total metal loading entering Spring Creek Reser~
voir. Obviously, this is a critical point, since if three
rather than five major. sources of contamination need to be
addressed, substantial savings in remedial action costs can
be achieved.
RESPONSE TO COMMENT 11-6
As stated in our remedial investigation, about 72 percent of
the copper and 86 percent of both zinc and cadmium were found
to originate from the five major sources at Iron Mountain
Mine for the period between February 29 through May 8, 1984.
In addition, it was pointed out that this was during relatively
dry weather conditions, which is not necessarily representative
of heavy rainfall conditions. Because of the complexity of
the Iron Mountain site and the extent of mine tailings and
acid mine drainages, both from point and nonpoint sources,
it would be extremely difficult to come up with an accurate
estimate of the contribution from each source at the site
duri~g varying rainfall conditions. It would be expected
that during initial rainfalls in the fall months, there would
be a large flush of metals from exposed ores. During this
periLod,. the metal 'loadings from these sources is expected to
result in a very large contribution. It is also possible.
that after this initial flush with heavy rainfall on the
mountain, flows from the Richmond portal, Lawson portal, and
Big Seep could increase substantially and represent an even
larger portion of the total metals contribution to Spring
Creek Debris Dam than' what was estimated during our rela-
tively dry winter period.
58

-------
The overall remed'iaiactions 'wer"e"; not based upon individual
metal-concentrations. or. loadin.gs. .fr.OJn. :any ..Qf the' five maj.or
sources', but were based .upon the overall metals leaving the
site and their effect on the Sacramento River below Keswick.
Source control alternatives were primarily directed toward
the Richmond orebody and the resultant acid mine drainage
leaving the Richmond portal and did not address the other
major sources. Surface water diversions were based strictly
upon the total metals leaving the site, not upon where they
originated from; therefore, whether the majority of the metals
were originating from three sources as opposed to five sources
do not appear to affect the cost of the overall remedial
action alternatives.
COMMENT 11-7
(Stauffer)
Subsurface flows' along Slickrock Creek are stated to account
for a substantial portion of metals, entering Spring Creek
during late May and early June, 1984. Indeed, the map on .
Figure 6-10 shows large increases in flow and metal content
(ninefold increase in copper content) in the lower reach of
Sl~ckrock. This single sampling effort on Slickrock is not
. adequate to draw this conclusion and should be followed up .,
to con£irm this finding. If true, this could be of greater
significance than is suggested .in the report because it has'
a direct bearing on the recommended remedial actions (ground-
water intercept).
RESPONSE TO COMMENT 11-7
As presented in Table F-22 in the Remedial Investigation
study, four surveys were made in the Slickrock Creek to deter-
mine additional sources of copper. The data suggest that
copper and other heavy metals are picked up as the stream
moves through old mining 'deposits. . It does not appear that
these observations have any bearing on our recommended
groundwater interception alternative.
COMMENT 11-8
(Stauffer)
The last six findings reported in the summary of the Remedial
Investigation Report relate to the behavior of subsurface
-""~-'-~'''''~r..cma-t'lTe'-pot'enticrl-~fo'r''-i-nt'ex~1:i~n';.,..b&fore','-i~eneGun,t-&r-s..-.~', ".. '-._-"
theorebodies. The available data, as presented, are
insufficient to draw any of these conclusions.
..
RESPONSE TO COMMENT 11-8
Three of the conclusions listed in the Executive Summary are
actually a listing of the results from hydrogeologic testing
rather than conclusions drawn from the data.
59

-------
The last conclusion listed in the Executive Summary states
that 17 gpm would be intercepted if tunnels are 100 percent
effective. It is not known if the tunnels will be this effec-
tive; therefore, we recommend further testing to determine
effectiveness (page I~3 of the Remedial Investigation).

The 17 gpm is estimated from the results of both the permea-
bility testing and analysis of the portal hydrographs. The
hydrographs analyzed included those from-both 1984 and 1985.
The 1984 conditions were after several years (1982 and 1983)
of greater than normal rainfall. The 1985 conditions were
after a year (1984) of lower than normal rainfall. The hydro-
graphs indicate approximately the same low flow conditions
during 1984 and 1985; therefore, the groundwater flow compo-
nent probably does not vary substantially. The temperature
data appear to ~~bstantiate the conclusion that low flow
conditions are associated with groundwater flow. During
times of low flow, the temperature associated with Richmond
portal AMD is approximately equal to the temperature of
groundwater measured in the monitoring wells (see page I-16
and Figure I-3 fo~ more detailed discussion) .
One of the conclusions listed in the Executive Summary is
that groundwater becomes contaminated as it flows through -
the massive su~fide orebody into the Richmond mine workings.
This was concluded from data that indicate (1) groundwater
is flowing toward the Richmond orebody, (2) the groundwater
quality as measured in the monitoring wells is much better
than the AMD flowing from the Richmond portal, and (3) the
base flow from the Richmond portal is on the order of
17 gpm.
The conclusion in the Executive Summary that describes the
relative contributions to the AMD is based primarily on
1984 data. However, some data from 1983 during relatively
wet months were used in formulating the conclusion. This
conclusion is based on analysis of the Richmond portal hydro-
graph and engineering judgment and should be re-evaluated
using additional data determined during subsequent testing
discussed in the Remedial Investigation and Feasibility
Report.
COMMENT 11-9
(Stauffer)
It is noted in this report that the evapotranspiration ,of
the. study area is considered to be 40 inches. Since rainfall
at the mine is considered to average about 80 inches, then
40 inches is available for runoff and infiltration below
depth of plant root zones. This amount of evapotranspiration
appears high considering 'the type of vegetation and soil
present and, in fact, contradicts data presented in the section
on hydrology (see below). This is a critical factor, since
the volume of infiltration has a direct bearing on the extent,
60

-------
if any, of surface' .cappi;Ilg and:,:s,ource control 'needed at this
site. /.. - .
RESPONSE TO COMMENT 11-9
The 40 inches of evapotranspiration referred to in this com-
ment was presented in the climate section of the remedial
investigation report for the purposes of presenting general
information. It- is t~e potential evapotranspiration for. the
site; not the actual which is dependant upon such factors as
soil moisture con~ent (including infiltration), type of
vegetation, and quantity of vegetation. This value was not
used in the determination of the effectiveness of surface
capping and source control alternatives presented in the
feasibility study report. .
COMMENT ll-l0'4Stauffer)
The soil is indicated as being Type C of the Soil Conserva-
tion Service runoff categories. This soil type has a slow
infiltration or higher than average runoff which could be
accentuated by the steep topography. Both factors are favor-
abie under these circumstances. Unless special conditions.
exist, infiltration would likely be less than 25 percent of
the total rain~a11 into undisturbed hillsides. Twenty-
five percent of 80 inches of rainfall is 20 inches, which
cannot support the 40 inches of evapotranspirati9n mentioned
above. The soil may be more permeable than Type C, but there
are no analytical or descriptive soil data supporting this
conclusion. These data need to be further explored and con-
firmed before any capping alternative can be considered.
RESPONSE TO COMMENT 11-10
The evaluation of effectiveness of the capping alternatives
was based on observed rainfall, historic rainfall, observed
discharge from the Richmond portal, and historic runoff from
the Spring Creek watershed. Soil types for est~ating runoff
from rainfall and the average evapotranspiration value were
not used in this analysis. As discussed in the Response to
Comment 11-10, the actual evapotranspiration at the site is
not directly related to the potential evapotranspiration of
40 inches.
COMMENT '11-11
( Stauffer)
On page 4-2, average monthly inflow to Spring Creek Reser-
voir is presented. The monthly inflows for February and
March, 119 and 124 cfs, do not correlate well with the rain-
fall figures on page 2-2 of 14.1 and 7.8 inches, respectively,
, for the same months. Thus, there is clearly a lack of corre-
lation of precipitation, infiltration, and surface water
flows critical to selection of an appropriate cost-effective
remedial action.
61

-------
RESPONSE TO COMMENT 11-11
The average monthly precipitation presented in the remedial
investigation report in Table 2-1 is not for the same period
as the inflow into the Spring Creek Reservoir presented in
Table 4-1. The information as presented in those. tables was
not used in the analyses o~ the effectiveness of source
control alternatives in the feasibility study, but was
presented in the ~I-to show seasonal variations of
precipitation and Spring Creek flows.
COMMENT 11-12
( Stauffer)
The objectives of the groundwater investigation of the Rich-
mond orebody spelled out on page 4-6 require a much more
comprehensive field effort than the four holes and limited
tests reported ~ Appendix I. These limited tests indicate
wide ranges in hydrologic properties. For example, permeabili-
ties from four pumping tests span almost two orders of magni-
tude, i.e~, 0.28 to 0.0042 foot per day. The transmissivities
are given as 13 to 480 gal/day/foot. There is no calculation
that would give rise to the conclusion that these values by
themselves 'are consistent with observed flows discharging
from the Richmond portal.
RESPONSE TO COMMENT 11-12
Within each borehole the two types of permeability tests
were reasonably consistent and the variation in permeability
was found to decrease spacially to~ard the orebody. This
variation in fractured rock is typical and should be expected.

The drain formula shown on page I-16 was used as an indepen-
dent check on the permeabilities determined from pump test-
ing. The results of this analysis indicated the average
permeability of the formation was approximately the average
of the extreme values measured in the testing program. Other
calculations using Darcy's Law were also performed, but not
published, that indicated the measured permeabilities were
consistent with the flow from the Richmond portal.
All the data collected were consistent: temporally, spacially,
and independent of method used. Therefore, we believe c~nclu-
sions can be drawn from the data. However, we agree that
the data did not completely define the groundwater flow around
the. mine, and we therefore recommend that additional work be
performed prior to final design. The work performed for the
Remedial Investigation and Feasibility Study is consistent
with the goals of thes~ reports.
COMMENT 11-13
( Stauffer)
A conclusion is made on page 4-7 that the discharge from the
Richmond portal is from three sources--lateral inflow,
62

-------
. .
rapidjnfiltratio~,.and surfac~~~~ter infiltration. This
seems' reasonable, but the' proportions-de.rived-.fr.om..the....... -'--.
unusually low flow 1~84 hydrograph studies are probably not
dependable, and certainly not sufficient to be used as a
basis for major engineering expenditures at the site.
RESPONSE TO COMMENT 11-13 .
EPA believes that these conclusions should be tested prior
to construction of the groundwater interception system.
When additional data are obtained, the contributions of the
different sources may need to be modified.
COMMENT 11-14
( Stauffer)
Recommendations for work on any subsurface intercept system
should be contittgent on results of surface water sealing and
diversion work. The type of work necessary to establish. the.
viability of underground intercept as a remedial measure
must be more elaborate than indicated and may well still
prove inconclusive. The fractured-rock hydrology in the
vicinity of a mine with numerous openings and levels of open-
ings can prove a deficient subject on which to develop reli-
able data.
RESPONSE TO COMMENT 11~14
. .
We tend to agree with the phased implementation program.
And as discussed earlier, additional data should be obtained
prior to construction of the groundwater interception scheme.
COMMENT 11-15
(Stauffer)
Chapter 6 contains several efforts at ranking the sources of
heavy metals pollution at Iron Mountain. Three sets of data
were obtained on flow rates and on the copper, zinc, and
cadmium contents from "intensive sampling" from a variety of
sources. These show that the Richmond portal, the Lawson
portal, and the Old No.8 mine seep constitute 92 to
99 percent of the total of these metals leaving the site.
This is in accordance with historical data. It should be
the basis for concluding that remedial action should be limited
to these specific sources, not the five suggested later in
the feasibility study.
RE&PONSE TO COMMENT 11-15
See response to Comment 11-16.
COMMENT 11-16
(Stauffer)
A further attempt of a mass balance covering a span of 10 weeks
from February 20 to May 8, 1984, is considered by CH2M HILL
63

-------
. .

to be more accurate than the above. The measurements were,
however, during an exceptionally dry period and are probably
no better than the intensive sampling data. These results
should be discontinued, and the sampling data cited above
should be used for considering remedial action.
RESPONSE TO COMMENT 11-16'
I,
- .
The RI report described mass balances that were obtained
under both wet weather conditions and also an I1-week period
during dry weather conditions. It was pointed out in the
report that during the two intensive surveys, five major
sources contributed 95 to 99 percent of the sum of the
copper, zinc, and cadmium. These April and December samp-
lings were made over a 2- to 4-day period which at times,
under varying r~~nfall conditions, probably caused major
variations in flow. In addition, the material balances were
made over an 1l-week period under relatively dry weather
conditions, in which all sampling was conducted within a
6-hour period and flows were accurately gauged. It would be
expected that the contribution of the five major sources
during dry weather conditions and under wet weather condi-
tions would vary. It was also pointed out in the RI report'
that the Richmond portal was the major contributor of acid
mine drainage from the site. All these results were taken -
into consideration in selecting remedial action alternatives.
Source control alternatives at the site only address the
Richmond orebody because this appears to be the major contri-
butor both under dry weather and wet weather conditions.
What determines which sources of acid mine drainage which
need remediation is based upon the reduction in metals
required to meet State .and EPA water Quality objectives in
the Sacramento River.
COMMENT 11-17
(Stauffer)
-
In Appendix D, the ESA geotechnic~l consultants letter report
(four pages) addresses the subject of "source control."
With regard to subsurface efforts, it states that a program
detailed enough to define the subsurface flow systems in the
area is probably not practical. Therefore, the four-hole'
test program recommended and completed was unnecessary and
of no benefit.
RESPONSE TO COMMENT 11-17
EPA believes that the testing program did obtain useful-data
from which meaningful conclusions can be made with regard to
groundwater movement and quantities.
64

-------
------------- -------'---------,
-,.t, .
COMMENT 11-18
(Stauffer)
j"}o'. ..- }.i .
Appendix D recommend~ backfilling of subsidence depressions,
including a clay capping. This recommendation appeared to
include total backfilling of the Brick Flat open pit, which
is impracticable because o~ its volume.
RESPONSE TO COMMENT 11-18
The recommendation includes backfilling of Brick Flat Pit to
an elevation that would establish gravity drainage from the
pit along the haul road cut at the south end of the pit.
Depending upon the method selected for drainage of the pit,
this may require a fill up to 16 feet deep in the eastern
portion of the pit. The recommendation does not include
filling the ent~~e pit. .
COMMENT 11-19
( Stauffer)
Mine exit sealing is suggested, but the report acknowledges
it is not practicable for the Lawson and Hornet tunnels. In
our opinion, sealing the Richmond portal would likely result
in water exiting from other places on the mountain side. . It
. i's impossible to seal the Old mine cmd..N,C? 8 mine sites.
RESPONSE TO COMMENT 11-19
We tend to agree.
COMMENT 11-20
(Stauffer)
For subsurface interception, use of "drainage tunnels" is
proposed, although it is recognized to be costly and uncertain.
Water quality from such tunnels may be contaminated and the
work of no use at this particular site.
RESPONSE TO COMMENT 11-20
Additional testing as recommended in the Remedial Investiga-
tion and the Feasibility Study should be performed to evalu-
ate the effectiveness of the groundwater interception drifts
.,. -~'.--'pr~-Or4o..j.IUp-J.~~E:~~!-~on. . However, we believe the technique
is feasible for interc.ep"€~'Otf"O'f-'qroundwater:,...._and,c..P.~9Q.1~~~!-....;,..", '
associated with intercepting areas of contaminated ground- :---:---._"--,-".-
water are not major design problems.
COMMENT 11-21
(Stauffer)
The evaluation of electrochemical processing alternatives
(by R. L. Clarke) is premature because the ultimate flow
rates and metal concentrations and proportions cannot be
known until the source control work is completed. Flows
certainly will be less than the 2,000 gpm and most likely
less than the 200 gpm rates that Clarke assumes.
65

-------
I "":'.~--'"-'-- .,
... ,. ..' .--~
RESPONSE TO COMMENT 11-21
Dr. Robert Clarke evaluated electrochemical alternatives for
metal recovery early in theRI phase of th~ Iron Mountain
Mine study. His evaluations were based upon existing flow
and metal concentrations that had been observed from Iron
Mountain Mine, and those eyaluations were intended only to
assist in screening of treatment technologies for acid mine
drainage. '
COMMENT 11-22
(Stauffer)
The letter from the Department of Health Services (Appen-
dix H) states that the mine area "poses a significant danger
to hikers who would go to that area." Stauffer disagrees
with this conclusion. This has pever been known to be a
problem, since ~he appearance of the stream (with iron stain-
ing and color) is such as to discourage casual exposure.
Other than flow direct from the Richmond and Lawson portals,
acidity is not so low as to cause any dermal hazard. .
RESPONSE TO COMMENT 11-22
EPA acknowledges Stauffer's opinion. However, the AMDladen
waters leaving the Richmond and Lawson portals is clear whe~
transported via' the flumes for treatment. The water in the
flumes could be mistaken as drinking water that is being
conveyed elsewhere for consumption.
COMMENT 11-23
( Stauffer)
The hydrologic tests in the vicinity of the Richmond orebody
used as a basis for establishing groundwater flow in that
area is inadequate. Four borings put down for that purpose
were pump tested, b~t equilibrium rates of extraction were
never achieved during the test period. The excessive draw-
downs produced invalidate the calculations of hydrologic
properties.
RESPONSE' TO COMMENT 11-23
EPA believes that meaningful conclusions can be drawn from
the - da~a-obta.~n:ed-' from'tne"-field"investigation.." -,~~~,,,",",=-,.-. --"'.,
Large drawdowns do not invalidate the use of pump tests but
can. produce some errors if properly evaluated. Errors can
be minimized by analyzing specific portions of the drawdown
and recovery data. Furthermore, during a constant discharge
pumping test, equilibrium conditions will not occur unless a
recharge boundary (i.e., stream) is encountered. The pump-
ing tests were evaluated using the standard non-equilibrium
formulas, and results were consistent with packer permeabil-
ity testing results. '
66

-------
COMMENT 11-24
(Stauffer) .
The conclusion that 17 gallons per minute of base flow would
be captured by groundwater placed on both sides of the
Richmond mine is speculation. For one thing, the 17 gallon
per minute base flow figure comes from the dry year of 1984.
Also, it is not established that the apparently near-constant
base flow in the Richmond portal actually derives from the
kind of groundwater flow that could be captured by "drainage
tunnels" or is lateral flow.
RESPONSE TO COMMENT 11-24
See response to Comment 11-8. We have also recommended that
additional testing be performed prior to implementation of
the groundwater interception drifts.
--.
- ..". "....~"..... ''''--.. .......---.-. _..."'..._-_..._-~_......_...._~-~..- -.- '--".'--"""..
. ---..... -""'-"~ -~..... .. . . ......... ~ ~ - ,.,. .'. - -.
. '--"-<-- ". ..,-. - 'h.- -
'., .-. """
~1("~~'.~.: I. ~.:..>...."..c ',~ '-;';:.::"
";, ; ~.;. : - &'~~~:':"::" ,-' . .-:--" .....
, . - .~ ;~...:;. ~ -".
. "-'-~.- --.
~;~'.-. -.. '":'.':"::-~':".; -
. '.:".';';"":':".:"-:''''
~---':;..'
. n. ..::..:.:;:;.: ";:;.."T' -,...._.~- '--
67

-------
CATEGORY 12--IMMI PROPOSAL
Several people commented regarding Iron Mountain Mines,
. Inc.'s proposed alternative. These were primarily people
currently or previously associated with Iron Mountain Mines,
Inc., or with previous min~ owners (Boyer, Davy Mc~ee-
Morgan, Davy McKee-Turk,'IMMI-Foster, IMMI-Arman, Katzakian,
Miller, McLean, ~ta~ffer, and Collier). These people
expressed several benefits associated with the project and
concerns with EPA's evaluation of. the IMMI alternative in
the Feasibility Study. These comments are paraphrased and
summarized below with corresponding responses.
COMMENT 12-1
. .
The IMMI propos~l would be an economic 'plus for the local
area, would not cost the taxpayer, and would allow use of
Superfund money for other projects. .
RESPONSE TO COMMENT 12-1
Assuming IMMI can obtain financing, the project could be
implemented without use of taxpayer money. EPA agrees that
these are both.positive benefits and are part of the reason-
why EPA is encouraging. IMMI to enter into a'n agreement
whereby IMMI can provide detailed information to back up its
claims that the project is econo~ically, technically, and
environmentally sound, and that future money would be
available to repair further environmental harm that might
occur should the IMMI proposal fail. Most importantly, the
legal duty placed upon EPAby CERCLA does not include
selection of a remedy that provides economiq benefit.
Instead, EPA's obligation is to choose a cost-effective
remedy that adequately protects human health, welfare, and
the environment. Therefore, economic benefit cannot be the
focus of EPA's analysis of remedial alternatives.
COMMENT 12-2
I
I
I .' _.....-
The alternative was treated in a superficial manner in the
Feasib~~ity.Stu9Y because EPA, RWQCB, and EPA's contractor
don't understarid the pro~osal." . . . '.
RESPONSE TO COMMENT 12-2
.The' IMMI alternative was not evaluated and compared to EPA
alternatives primarily for three reasons:
1.
The proposed IMMlalternative was received by EPA
one week prior to publishing the draft Feasibility
Study Report.
- 68

-------
,."
The IMMI alternative cannot be compared on a
cost-effective basis with EPA alternatives because
EPA cannot .implement a commercial mining facility.
Therefore, it is considered a potential alterna-
tive that could be implemented in lieu of EPA's
selected alternative.
2.
3.
There was not enough information available to
determina if the project was technically,
economically, and environmentally feasible. That
is why IMMI consultants are planning pilot studies
and marketing studies.
EPA must be assured that the combined processes will work,
project cleanup objectives will be met, and the project will
not create a worse (potential) environmental problem than
the one it is trying to solve. If needed, IMMI will be
required to design and construct additional remedial actions
to meet site cleanup objectives. Assurances must also be
made that funds will be available for all post-closure site
cleanup activities that will be designed to ensure that site
cleanup objectives will continue to be met.
Without all of the above assurances, EPA cannot consider
selectinq the proposed IMMI alternative. Although the IMMI
proposal was initially screened in the Feasibility Study, -
EPA has made it very clear that it would consider the IMMI
proposal if it could be demonstrated that it was as effec-
tive as the EPA cleanup program. In fact, in a meeting on
July 25, 1985, with IMMI, EPA outlined three options under
review by the Agency for considering the IMMI proposal as a
solution to the IMMI problem. IMMI was afforded the oppor-
tunity of selecting one of the three options. These three
options were described in a letter to IMMI, dated Septem-
ber 4, 1985. In late September 1985, IMMI verbally stated
its preference to proceed with the third option, under which
IMMI would proceed at its own risk.

EPA has also retained a consultant to evaluate the technical
feasibility of IMMI's proposed in~situ leaching and metals
recovery process, and to evaluate the marketability of the
proposed products generated by this process. These evalu-
ations, toqether- with any additional information suppl.ied..by--- ~ ,
IMMI, will be used as a basis for future consideration of
theIMMI proposal.
.
It is EPA policy to have potentially responsible parties
fund needed site 'investigation and cleanup activities to the
extent that these activities are conducted in strict accor-
dance with the NCP and will result in meetinq project objec-
tives. However, if these activities will not be conducted
in a timely and expeditious manner, and thePRP has not pro-
vided certain financial assurances, EPA will proceed with
69

-------
the needed action.
Mine s"i te.
Tpis is the case with the Iron Mountain
COMMENT 12-3
EPA's proposed alternatives would prevent future mining of
mineral resources.
RESPONSE TO COMMENT 12-3
EPA's recommended alternative may have an effect on future
mining, but would not preclude future mining activities.
COMMENT 12-4
The information in the Feasibility Study Report was biased
against the IMM~. proposal and was aimed to discredit it.
RESPONSE TO COMMENT 12-4
The information provided in the Feasibility Study Report was
not intended to be biased or for the purpose of discrediting
IMMI's proposed alternative. In fact, page ES-8 of the Fea-
sibility Study Report states: "The inherent advantage of .
the proposed IMMI alternative is that it would be construc--
ted and operated by IMMI. In addition, should it function
as described by IMMI, it could be the only profitable alter-
native."
Technical and environmental concerns were identified in the
Feasibility Study Report based on information provided to
EPA at the time the report was prepared. Some of these tech-
nical and environmental questions have been answered,
whereas others will have to be answered as the result of
further studies mentioned above. .
COMMENT 12-5
The IMMI proposal is an innovative project and recycles
metals, which is encouraged by the NCP, whereas EPA's pro-
posed alternatives do not recycle.
RESPONSE TO COMMENT 12-5
EPA agrees that the IMMI project is innovative and recycles
waste. . This is the reason EPA has stated that it will con-
sider the IMMI proposal provided the assurances described in
the response to Comment 12-1 are met.
70

-------
,
CATEGORY 13--0THER REMEDIAL ACTION ALTERNATIVES
....,
COMMENT 13-1 (Collier)
Placement of a permanent cap will prevent additional mining
and put IMMI out of busin~ss. Wouldn't a feasible alterna-
tive be oiling of the surface as a temporary measure; this
would prevent water percolation, would test whether a cap
will even work, and would allow possible implementation of
IMMI's alternative in the future. .
RESPONSE TO COMMENT 13-1'
Oiling would not necessarily prevent inflow and infiltration
into the orebody.
-.
Placement of a permanent cap would not necessarily prevent
additional mining on the site.
Results of the Feas.ibility Study indicate that a cap would
be effective in reducing the discharge of acid mine drainage
fro~ the site.
The Feasibility: Study is looking at permanent remedies to
the problems, not temporary solutions.
COMMENT 13-2 (Nor)
EPA and the other concerned agencies should consider the
potential economic benefits of maintaining a viable mining
operation. WhileEPA is not in the private enterprise busi-
ness, the. government is in the mining business, through the
Bureau of Mines. It would seem possible for the government
and private industry to take joint action that would allow
continued mining. If this possibility of continued mininq
is not investigated, all of the alternatives have not been
considered. .
RESPONSE TO COMMENT 13-2
If the IMMI proposal is allowed to proceed, it must be
financed with private capital since the purpose of the
Supe~fund is to elimiinate the danger posed by a hazardous
waste site. Congress did not intend the fund to be used in
commercial ventures. Therefore, a joint venture at IMMI is.
not a realistic alternative. A joint venture with the
Bureau of Mines would have to be discussed with that Agency.
COMMENT 13-3 (Ross)
Alternatives that include diversion of Upper Spring Creek
would cause flooding of his property; similarly, diversion
71

-------
of the. South Fork Spring Creek would damage other proper-
ties. .' The City of Redding's proposed hydroelectric project
would divert Upper Spring Creek to the Keswick Lake area,
which would prevent property damage and also have the eco-
nomi'c benefit of generating hydroelectric power. Why wasn't
this alternative considered in the Feasibility Study? If
the City of Redding does i~plement this project, would EPA
consider it in lieu of the diversion alternatives included
in the Feasibili~y Study Report?

RESPONSE TO COMMENT 13-3
The Spring Creek diversion
downstream property owners
of the effect will have to
design.

If the City of Redding implements its proposed pump storage
hydroelectric project on Upper Spring Creek, the Spring Creek
diversion discussed in the Feasibility Study Report may not
be required. There is no assurance that the City will build
this project. However, if it is built, it would serve the
same purpose as the proposed Spring Creek diversion. EPA'
would like to keep this option open if the City obtains the
necessary permits and licenses to construct its hydrgelec- -
tric project. "
alternative may have an effect on
living on Flat Creek. The extent
be determined during final
COMMENT 13-4 (Stauffer)
Stauffer Chemical Company believes that more cost effective
remedial options should be available to meet both EPA and
California water quality criteria than have been proposed in
the Feasibility Study. In contrast with option CA-7, which
would cost a staggering $42.8 million, it is our opinion
that options should be available at an expenditure of
approximately $5 million.

Once such option would combine (1) alternative WM-1, the
diversion of upper Spring Creeki (2) treatment of mine drain-
age from the Richmond and Lawson portals to remove copper,
zinc, and cadmiumi and, (3) control of the reduced discharge
volumes from the Spring Creek Debris Dam to ensure adequate
dilution.
Alternative WM-1 would serve to divert up to 800 cfs or
1,~O acre feet per day of flow from the Spring Creek Debris
Dam reservoir. Diversion of this flow would render unneces-
sary the proposal to increase the reservoir capacity. With'
those reduced volumes, it wou~d be feasible to obtain suffi-
cient dilution at the Keswick Dam in the Sacramento River to
meet water quality criteria under varying conditions of flow
from Shasta Dam.
72

-------
, . '.
An additional advantage of Alternative WM-l is the possibil-
ity of --combining this alternative with the installation of a
hydroelectric facility for the generation of power. The
diversion of Spring Creek would involve about a 1,DDD-foot
drop requiring some form of energy dissipation to avoid mas-
sive erosion and silting problems. Passive means for energy
dissipation have been propo~ed in the Feasibility Study
under option WM-1. .The recovery of hydroelectric power,
however, would provide for the utilization of a natural
resource, as well as economic return.
Treatment of AMD from the Richmond and Lawson portals would
provide for up to a 50 percent reduction in the dissolved
copper concentration and as much as a 90 percent reduction
in zinc and cadmium concentrations at the Spring Creek
Debris Dam. Improved treatment of AMD from these two
sources combinecr-'with the diversion of upper Spring Creek
and the control of flow from the Spring Creek Debris Dam
should permit compliance with water quality criteria at the
Keswick Dam discharge.
There appears to be general agreement with a phased or
stepwise approach to the IMM acid mine drainage problem.
Although we believe that the above lower cost alternative
would meet water quality criteria, additional remedial steps-
are entirely feasible and could be subsequently incorporated
if proven to be necessary. The foregoing option will be
more completely reviewed, together with other options, in
preparation of our further comments to be submitted by Sep-
tember 3D.
RESPONSE TO COMMENT 13-4
According to the analyses presented in Appendix G, it is not
likely that the alternative of WM-l, treatment of two major
sources and operation of Spring Creek Debris Dam, would meet
objectives and it certainly would not meet all applicable,
relevant, and appropriate federal and state requirments.
For example, Alternative No. 12 on page G-27 of the
Feasibility Study Report includes WM-l-, treatment of five
major sources, groundwater interception, and diversion, and
assures efficient operation of Spring Creek Debris Dam.

EPAagrees with a stepwise approach to the implementation
and monitoring of remedial actions.
EPA would seriously consider allowing Stauffer to implement
its $5 million remedy if it could prove that it wouldsuc-
ceed in meeting cleanup objectives for 1978 conditions.
73

-------
COMMENT 13-5 (FWS)

. .
One alternative not fully addressed is construction of a
combined inflow and pumped storage dam in the Spring Creek
basin upstream from the confluence of Boulder Creek. This
measure is presently being proposed by the Cityo£ Redding
in their application for license to the Federal Regulatory
Energy Commission for a hydroelectric project in Spring
Creek (project'Nq. 8499). The project would provide a stor-
age dam to receive both inflow from upper Spring Creek and
pumped storage from Keswick Reservoir. The proposed project
would have the capability of diverting and releasing up to
1,600 cfs from the upper Spring Creek basin; thereby elimi-
nating the occurrence of spills from Spring Creek Debris
Dam. This alternative .would provide the additional benefit
of hydroelectric energy capacity for 110 MW, enough to pay
for the project,. Our initial assessment of the City of
Redding's proposal is that it would greatly benefit anadro-
mous fish resources. The Service strongly recommends that
this alternative be fully addressed in the Feasibility
Study. . .

RESPONSE TO COMMENT 13-5
This alternative would h~ve the same effect as the diversion
. of Spring Creek, which has already been evaluated. The dif-
ference is that the hydroelectric project would be implemen-'
ted by the City of Redding, reducing the overall cost of the
selected combined remedial action alternatives. As stated
in the response to comment 13-3, EPA will keep this option
open.
74

-------
CATEGORY 14--PREFERRED REMEDIAL ACTION
COMMENT 14-1 (CDFG)
As trustee of California's ,fish and wildlife resources, our
department seeks full protection of those resources in the
upper Sacramento River. Of the alternatives listed, CA-7
comes the closest to that goal. We support this alterna-
tive, given that each component of the waste control system
is evaluated after construction and measures are added as
necessary to achieve full protection. Such additional mea-
sures could include effluent treatment, adjusting the debris
dam storage capacity, and coordinating releases from Shasta
Lake, Spring Creek Reservoir, and Spring Creek Powerhouse.
. .......
RESPONSE TO COMMENT 14-1
EPA appreciates the support of CDFG. We anticipate that
implementation of remedial action at IMM will" achieve our
mutual goal of protecting the fish and wildlife resources of
the" Sacramento River.
COMMENT 14-2 (Rardin)
As citizens, we are concerned about the pollution created at
Iron Mountain and support your efforts to remedy the prob-
lem. " We encourage you to consider combined alternative num-
ber four, which calls for complete capping, grou~dwater
interception, and treatment by lime/limestone. We believe
that capping and groundwater interception are important in
that they are preventive; that is, waterways would not be
polluted to the existing extent.

If the Environmental Protection Agency should select a com-
bined alternative that includes the building of a diversion
dam on Spring Creek, we strongly request that you consider
rerouting the water to Keswick Dam rather than down Flat
Creek. We own approximately 16 acres on Flat Creek on Iron
Mountain Road. On our land, there are two residences and
several other buildings that may be affected by routing
Spring Creek down Flat Creek. There are also concerns about
soil.erosion and the quality of our water supply and system,
which water is obtained from the north fork of Flat Creek
where it joins Flat Creek proper. .
We do not want to be relocated in the event that you should
select diverting Spring Creek down Flat Creek. We ask that
you consider other solutions rather than forcing the sale of
private property, not only for ourselves, but also for other
private property owners along both Flat and Rock Creeks.
7S

-------
RESPONSE TO COMMENT 14-2
EPA will take whatever steps are necessary to mitigate
impacts that are expected to result .from the diversion of
Spring Creek, if the diversion is implemented by EPA rather
than the City of Redding ~see Response 13-3).
The Department of_H.alth Service~ (DOHS) has also provided
the following response to Comment 14-2:
The Feasibility Study assumes that no residential water,
other than the Redding municipal system, is potentially
affected by effluent from the Iron Mountain site. A deter-
mination should be made as to whether any residences are
using or could use onsite water for household purposes.
,~.
COMMENT 14-3 (Stauffer)
.. .
Combined alternative CA-6, which calls for enlargement of
the Spring. Creek Debris Dam and the resulting increase in
storage capacity to 13,000 acre feet, diversion of Upper
Spring Creek, diversion of South Fork of Spring Creek, and
.copper cementation, is less costly than Option CA-7 by
approximately $10 million. The EPA, however, announced its -
preference for Option CA-7 at the public meeting in Redding,
California, on August 15.

According to this report, (page ES-8) combined alternative
CA-6 fully complies with all applicable or relevant stan-
dards, guidelines, and EPA Superfund advisories. . Assuming
that the cost estimates are correct, there appears to be
insufficient justification for EPA to select alternative
CA-7 in favor of alternative CA-6. Stauffer Chemical Com-
pany, however, believes additional remedial options can be
developed which would be more cost effective by an order of
magnitude~ that is, in the range of $5 million. We intend
to outline these options in our subsequent comments to be
submitted by September 30.
Combined alternatives CA-5 and CA-7, which also meet all
applicable or relevant standards, guidelines, and advisor-
ies, are substantially more expensive than alternative CA-6
and do not provide sufficient benefits over CA-6 to justify
the added cost. Therefore, by comparison, alternatives CA-S
and CA-7 are not cost effective and should be rejected .as
inconsistent with the National Contingency Plan. .
RESPONSE TO COMMENT 14-3
When compared to CA-6, EPA believes that Combined Alterna-
tive CA-7 better rneets the intent of the NCP because it:
o
Minimizes of the production of waste/AMD, and
76

-------
o
Addresses. the hazardous waste problem at its
source
Combined Alternative CA-6 does neither, but relies strictly
on d~lution to meet project cleanup objectives. Combined
Alternative CA-~ provides a good balance of source control,
treatment, and water management alternatives to meet cleanup
objectives. .
,
As stated in Response 13-4, EPA would seriously consider
allowing Stauffer to implement its $5 million remedy if it .
could prove that it would succeed in meeting cleanup objec-
tives for 1978 conditions.
COMMENT 14-4 (RWQCB)
For reasons whieh we have previously discussed, we request
that EPA implement a control alternative which includes some
measure of source cQntrol. Although we concur with the over-
all program objective of meeting state or federal water qual-
ity objectives at Keswick Dam, we feel strongly that 'the
selected control program should result in significant water
quality improvement upstream of this point; i.e., lower Kes-
wick Reservoir and the Spring Creek watershed.' This will be
the case only if EPA selects a control strategy aimed.at
reducing acid/heavy metal discharges from the major sources
at the mine. Of the alternatives listed in the Feasibility
Study, we recommend that EPA select CA-7 for implementation.
This alternative, which combines source control and water
management approaches, meets the program cleanup objectives
even in the most critical year evaluated and appears to pre-
sent an opportunity for shared responsibility between the
state/ EPA and the Bureau of Reclamation. We are aware of
the efforts by EPA and the Bureau to develop an Interagency
Agreement defining this implementation responsibility, and
we commend these efforts. .
. ,
We believe that implementation of the selected control
alternative should be a phased program with source control
~ctions receiving first priority. If evaluation of the ini-
tial source control actions shows that we have not achieved
a satisfactory level of control, additional actions, source
control, and/or water management should be implemented. -In
previous correspondence, we have expressed reservations
about the upper Spring Creek Diversion. We would not recom-
mend implementation of this component of CA-7 until addi-
tional studies are made on its positive and negative
impacts. .
With regard to the Mine owner's proposal for a commercial
mining operation as a solution to the problem, we believe
that Iron Mountain Mines, Inc., should be given the oppor-
tunity to test this proposal and to determine if it is a
77

-------
. '
techni~ally and economically feasible method of controlling
the discharge of toxic substances from the Mine. However,
until further information is provided which verifies that
this is a viable process at the Iron Mountain Mine site, the
proposed actions and schedule of the Superfund Program
should not be altered. We were informed by Iron Mountain
Mines, Inc., and the Davy'McKee Corporation in July 1985,
that the required te~ting of their solution mining proposal
would take six to'eight months. Therefore, there should be
no conflict between the completion of this testing and the
scheduled implementation of Superfund alternatives if the
solution mining plan does not appear feasible. .
RESPONSE TO COMMENT 14-4
EPA agrees with a phased implementation approach. The pro-
per phasing of alternatives will be determined during proj-
ect design. .
EPA will consider IMMI's proposal if IMMI provides the
required information and assurances, as discussed in prp.-
vious categories.
COMMENT 14-5
(Conservation)
Our specific recommendations are:
1.
The "No Action" proposals be implemented for both the
mine workings and the surface water until the Iron
Mountain Mines, Inc., proposal for in situ solution
mining is evaluated. We believe this evaluation should
be completed within one year.

If that evaluation indicates that in situ solution
mining is not feasible, then we would recommend a
combination of copper-cementation of the acid mine
drainage, transbasin diversion of upper Spring Creek,
and enlargement of existing storage capacity of Spring
Creek Reservoir.
2.
- .
RESPONSE TO COMMENT 14-5
1.
The extent of the environmental problem, the impact on
public welfare, and potential pH health impacts.
presentad by IMM site do not support the "no action"
. alternative.
2.
The alternative proposed above does-nothing to address
the problem at its source and relies strictly on
dilution to control the problem. EPA cannot evaluate
the above alternative because it has not proposed
specific figures for the enlargement of Spring Creek
Debris Damr this precludes EPA from determining if the
project will meet site cleanup objectives.
78

-------
COMMENT 14-6
(Agriculture)
In addition to CA 6, -the CDFA favors adoption of the com-
mercial ore recovery option since it is the only profitable
alternative available. We recognize that this is not a
presently viable option since, as stated on page 9 of the
executive summary of the. feasibility study, delaying cleanup
of the site while waiting for more information to adequately
assess the sufficiency of this alternative would risk public
health and environment. Therefore, this department recom-
mends adopting CA 6 with the proviso that the commercial ore
recovery option be employed if the necessary information'
becomes available in time to effectively evaluate this
alternative and if the alternative is found to be
sufficient.
RESPONSE TO COMMENT 14-6
No response required.
79

-------
,_4'
CATEGORY 15--0THER CONCERNS (MISCELLANEOUS)
COMMENT 15-1 (Wilson)
If the problem at Iron Mountain Mine is solved, would there
still be other sources of pQllution that would continue to
create problems]
'RESPONSE TO CO~~ENT 15-1
In the Spring Creek watershed, there is another source of
pollution, but it represents less than 1 percent of the
total metal load in that stream. By solving the Iron Moun-
tain Mine problem, most of the pollution in the Spring Creek
drainage would be controlled. In addition, as the alterna-
tives show, the fish in the Sacramento River would be pro-
tected. -.
There are other mines in the Shasta Lake watershed area that
discharge into the lake. However, the levels of those.
metals entering the Sacramento River system are mitigated by
the fact that Shasta Lake is a huge reservoir of neutral
water that tends to precipitate those metals out. Some of
these sites alluded to above are proceeding under state
enforcement action to abate discharges to receiving waters.
It is possible that the remaining sites will be similarily
required to implement site cleanup plans.
RD/R78/028
80

-------
PUBLIC COMMENTS ON JULY 25, 1986,
PUBLIC COMMENT FS ADDENDUM
Seventeen individuals, organizations, and agencies submitted
specific comments during the public comment period. In addi-
tion, three form letters were submitted with a combined total
of 30 signatures. The following list includes the names of
the cornmenters, their affiliation, and the manner in which
their comments are identified in this report. The names
listed in the last item are those individuals who signed one
of the form letters. Some signatures were not legible.
JULY 25, 1986, FS ADDENDUM-
LIST OF COMMENTERS
Wanda Hunt Babcock,Citiz~n, Babcock
"..."
Morgan Orwig, Citizen, Orwig
William H. Martin, Citizen, Martin
Mary L. Girard, Citizen, Girard
U.S. Bureau of Reclamation, Bureau
U.S. Department of Interior, Office of the Secretary,
Secretary

Paul Contini, Citizen, Contini
Tom B. (signature not legible), Citizen, Tom B.
Joanne Danielson, Citizen, Danielson
Bruce Boyer, IMMI Consultant, Boyer
Davy McKee Corporation, Davy McKee-Morgan
Iron Mountain Mines, Inc., IMMI-Arman
Daniel C. McLean, IMMI Metallurgical Consultant, McLean
Robert S. Miller, Citizen, Miller
Anette and Bob Rardin, Citizens, Rardin
Stauffer Chemical Company, Stauffer
u.s. Fish and Wildlife Service (written), FWS
Form Letter Signatures:
Donald West
Roger L. Campbell
80

-------
Rgn Young
Florence J. Maddox
John M. Maddox
Raymond E. L~slie
Barbara Fargo
Joe Fargo
Steve Maddox
Allen K." Buck
Sara Buck
Tony Bettencourt
Darlent Bettencourt
Charlotte Buck
Elaine Johnston
Charles A. Parsons
K. M. Parsons
Wayne P. Carnes
Todd E. Carnes
Bert Sharp
Wm. H. Martin
D. L. Eickenberg
Not Legible
Bruce Boyer
C.D. Shearman
Philip J. Nider
Don B. BroWn
: Aloma J. .Stull
Donald G. Bowers
Barry Boyer

Many of the commenters raised similar questions and concerns
regarding the Feasibility Study Addendum Report. For this
reason, the comments were paraphrased and summarized in a
. number of categories. Every attempt was made. to accurately
paraphrase comments and respond to all comments" that
required a response. All comments in their original form
are included in the appendixes.
The comments and their responses to the Feasibility Study
Addendum are grouped into the following categories:
AI.
A2.
A3".
" "A4.
AS".
.. A6-.
A7.
A8. "
A9.
A10.
All.
A12.
A13.
General Comments on Feasibility Study Report
Study Findings and Methodology
Environmental and Public Health Hazards
Costs of Remedial Action
Liability for Iron Mountain Mine Problems.
IMMI"Proposal
Other Remedial Action Alternatives
Preferred Remedial Action
Other Concerns (Miscellaneous) .
Proposed New Combined Alternatives CA-8 and CA-9
Comments Relating to Component Alternatives
Comments Relating to the Clean Water Act
Comments Relating to the Point of Compliance
81

-------
...'
CATEGORY Al-~GENERAL COMMENTS ON THE
FS REPORT
COMMENT Al-l (McLean)
The major difficulty with' the whole CH2M H,ILL feasibility
study .is that it ~s an attempt made by inexperienced engi-
neers to apply technology, which has been developed for con-
ventional hazardous waste disposal sites (landfills) located
on relatively flat ground, to rugged, highly faulted moun-
tainous terrain containing huge old mine workings. This is
a problem requiring the skills of specialized geologists,
hydrologists, and mining and civil engineers with mining
operation experience. No such personnel have been observed
on this project .~t any meetings I have attended. Consul-
tants' used by the' EPA have never visited the IMMI property
or tried to communicate with the IMMI staff despite its
offer of full technical cooperation.
The result of the obvious inexperience involved is the gen-
eration of a mass of confusing data and vague interpreta-
tions which provide no real basis for judging the actual
effectiveness of any of the alternatives proposed. No qual--
ified engineering firm could accept this type of report as a
basis for selection of a viable abatement system. It is
difficult, therefore, to understand why non-technical EPA
staff members evidently believe they are in a position to .
make multi-million dollar judgments using the inadequate
information contained in these CH2M HILL reports.
RESPONSE TO COMMENT Al-l
Much of this comment reflects the commenter's opinion, for
which there is no response. The response to the remaining
portion of the comment will attempt to help clarify the mis-
understandings that the commenter apparently has with
respect to the following categories:
o
o
o
,9
Applicable technologies for the site
Qualified specialists involved in the study
Site visits
Consultant's coordination with the IMMI staff
Applicable Technologies

A technology screening was performed during the Public Com-
ment FS which considered several technoldgies. Members of
the IMM Technical Advisory Committee (TAC) participated in
the screening process. The expertise of the members is dis-
cussed below. This screening process resulted in the appli-.
cable technologies used to develop the nine combined alter-
natives presented in the Public Comment FS and the subsequent
82

-------
FS Addendum. These screened technologies used-in the alter-
natives are listed below: .
o
Lime/limestone neut~alization of acid mine drainage
o
Surface water diversions
o
Enlargement of -ari equalizing reservoir
Capping over the orebody
o
o
Groundwater interception
o
Injection of LDCC
Some of these technologies could _be used on "landfill type"
hazardous waste sites on relatively flat ground. It is
unlikely that groundwater interception, injection of LDCC,
and enlargement of a reservoir would be used on a landfill
site. Capping is a common technology used on landfill sites
and probably not very common for use on mine waste sites.
Lime/limestone neutralization and surface water diversions
could be used on landfill sites, but are probably more
applicable to the IMM site.

Qualified Specialists -
EPA's contractor put together a project team which included
qualified specialists in the requisite areas of expertise to
develop the alternatives identified in the feasibility study
process. The project team included mining engineers, civil
engineers, geologists, hydrologists, and chemists. In addi-
tion, a technical advisory committee was formed which
included staff from the U.S. Bureau of Mines, Colorado
School of Mines, a geochemist from the USGS, EPA staff with
experience in mining, and several' other members.
Site Visits
Essentially all key staff assigned to the Iron Mountain Mine
project visited the site.
Consultant Coordination
EPA's consultants met with IMMI staff and exchanged-several
tel~phone calls at EPA's direction.
83

-------
CATEGORY A2--STUDY FINDINGS AND METHO~OLOGY
"
COMMENT A2-1
(McLean)
The Public Comment FS Addendum presents no quantitative com-
parisons as to the actual remedial effectiveness of each
alternative.
RESPONSE TO COMMENT A2-1
Combined Alternatives CA-1 through CA-9 were developed to
meet. two sets of water quality criteria (EPA Water Quality
Criteria for the Protection of Aquatic Life and the State
Basin Plan objectives). These criteria are presented on
page 4-1 of the August 2, 1985, Public Comment Feasibility
Study. As sho~.in Summary Tables 3 and 4 of the July 25,
1986, Feasibility Study Addendum, all combined alternatives,
except CA-I, meet these criteria. - .
The effectiveness of individual component alternatives in
reducing spills from Spring Creek Debris Dam and reducing
metals entering the Sacramento River are presented in
Tables 7-4 and 7-5 of the Feasibility Study Addendum.
COMMENT A2-2
(McLean)
The FS Addendum presents questionable capital cost data with
no backup data for confirmation.
RESPONSE TO COMMENT A2-2
Detailed cost estimates for the new component alternatives
are presented in Appendix A of the Feasibility Study Adden-
dum. Detailed cost estimates for the component alternatives
developed previously were presented in Appendix A of the
August 2, 1985, Public Comment Feasibility Study. These
individual component alternatives were assembled to form the
combined alternatives, and the individual costs were summed
to determine the total cost of the combined alternatives.
These costs should fall within the acceptable -30 +50 cost
range required by EPA.
COMMENT A2-3
(McLean)
The~ch~ice of equipment for the various processes for the
alternatives presented in the FS addendum indicates a poor
understanding by the report writers. An example is the
inclusion of a $2.9 million belt filter to dewater sludge
which is to be deposited in an open pit.
84

-------
RESPONSE TO COMMENT A2-3
Various dewatering te~hniques were investigated during pre-
vious pilot plant studies conducted for the Water Resources
Control Board. The preliminary selection of the belt filter
for dewatering the lime sludge was based upon the limited
onsite land available for the dewatering facility and the
need to dewater the lime sludge to provide a lower volume of
sludge such th~t-the storage capacity in Brick Flat Pit is
sufficient for a 30-year period.
The preliminary selection of other process equipment in the
cost estimates was based on previous operating data from
full-scale lime neutralization plants.
COMMENT A2-4
(McLean)
-.
None of the alternatives proposed (with the exception of
major stream diversions or reservoir enlargements) have an
indicated life span of more than 30 years; which for cost
involved is totall~ unacceptable.
RESPONSE TO COMMENT A2-4
Page A-l of the August ~, 1985, Public Comment Feasibility -
Study explains that all cost estimates are performed using a
30-year project life, as directed by OMB Circular No. A-94,
to allow the federal government to compare this project with
other federal projects.
COMMENT A2-S
(McLean)
There is no indication of actual annual operating costs for
each alternative so that the public or legislators can know
exactly what state tax burdens would be involved for the
perpetual future. .
RESPONSE TO COMMENT A2-5
As explained on page A-l of the August 2, 1985, Public Com-
ment Feasibility Study, the annual O&M costs were evaluated
using their present worth value as directed by OMB Circular
No. A-94. The annual O&M cost is about 10 percent of the
total present worth O&M cost.
COMMENT A2-6
(Miller)
Tables 5 and 6 of the FS Addendum, which compare various
. components of project alternatives on the basis of a rela-
tive cost benefit scale, give no indication as to what the
benefit to actual value might be.
85

-------
RESPONSE TO COMMENT A2-6
The relative cost-benefit data presented. in Summary Tables 5
and 6 were calculated from the data presented in Tables 7-4
and 7-5. The actual costs of the component alternatives and
their expected benefit in spill an~ metals reductions are
presented in Tables 7-4 an4 7-5.
COMMENT A2-7
(Stauffer)
The evaluation of CA-8 and CA-9 presented in the FS Addendum
is inadequate. There is insufficient consideration of the
"engineering implementation" or technical feasibility of
each of these alternatives. There is insufficient consid-
eration of costs for the two new alternatives. Implementa-
tion of one of these alternatives would be one of the most
expensive Super~~nd cleanups in the nation.
RESPONSE TO COMMENT A2-7
EPA does not agree with the above comment. All components
of CA-8 and CA-9, with the exception of LDCC, are proven
technologies that are both technically feasible and can be
implemented at IMM. EPA agrees that there are some
unanswered questions concerning the technical feasibility
and implementaQility of LDCC. For this reason EPA is pro-
posing to conduct a groundwater investigation and pilot and
demonstration testing of LDCC.
COMMENT A2-8
( Stauffer)
A further shortcoming of this addendum (in fact the entire
Feasibility Study) is the ,failure to include .and properly'
cost the disposal of the waste from the lime/limestone
treatment system. EPA has stated that under RCRA regula-
tions, this waste might be characterized as a hazardous
waste (we disagree) ~ The requirements for disposal of this
waste and the costs, of such disposal are not properly con-
sidered or included in this study. These requirements would
add substantially to the cost of any alternative considered
at this site employing lime/limestone treatment, but would
have a particularly large impact on CA-8 because of the
large volume of waste generated from the multiple streams'
being: treated.
RESPONS£ TO COMMENT A2-8
As stated in the FS Addendum, the lime/limestone sludge gen-
erated with Alternatives CA-8 and CA-9 would be dewatered
and disposed of in Brick Flat Pit, which has a capacity of
30 years of sludge storage. ' The cost of the dewatering
facilities, access road to Brick Flat Pit, O&M, and costs
for solids transport and disposal are included in the cost
estimates for these alternatives.
86

-------
. .

If RCRA does apply to the. lime/ limestone sludge disposal,
then the cost of a RCRA-approvedlandfill would add substan-
tial costs to the sludge disposal.
-~.
87

-------
.'
CATEGORY A3--ENVIRONMENTAL AND
PUBLIC HEALTH HAZARDS
COMMENT A3-1
(IMMI-Arman)
Salmon runs in 1986 are the highest ever experienced by com-
mercial fishermen_.Why then do the Water Board and the Depart-
ment of Fish and Game claim that minerals from IMM are killing
salmonids and fingerling trout?
RESPONSE TO COMMENT A3-l
There are documented fishkills that have been directly attri-
buted to the discharge from IMM. A detailed discussion of
the environment~. concerns is presented in the August 2,
1985, Feasibility Study.
COMMENT A3-2
( Stauffer)
In selecting a remedial action, EPA should be mindful that
the acid mine drainage sought to be controlled does not pre-
sent a threat to public health~ The concern is a low order
environmental concern relating to fishkills1 therefore, EPA -
should adopt a far more cost-effective remedy than proposed
in CA-8, CA-9, or the previous Alternatives CA-l through
CA-7.
RESPONSE TO COMMENT A3-2
Although IMM presents a potential public health threat, it
has, and continues to present serious impacts to the envi-
ronment and the welfare of the public. . The impacts on the
environment and aquatic life have been clearly documented by
the RWQCB and CDFG. These are reasons alone for EPA to con-
sider spending public funds to abate the IMM problem.
COMMENT A3-3
(Rardin)
Have any provisions been considered for the safety of life,
personal and real property for the proposed Spring Creek
diversion to Flat Creek?
RESPONSE TO COMMENT A3-3
The~e p-rovisions will be considered during the final design.
However,. the cost estimates presented in the FS include cost
for these types of provisions. .
. I
88

-------
CATEGORY A4--COSTS OF REMEDIAL ACTION
.'
COMMENT A4-1
(Miller)
What is the EPA definition of cost-effectiveness in terms of
finite dollars?
RESPONSE TO COMMENT A4-1
Cost-effectiveness is defined as the lowest-cost alternative
that effectively minimizes threats to and adequately pro-
tects the public health, welfare, and the environment. Cost-
effectiveness does not have a finite dollar amount, and is
used to compare the relative cost and effectiveness of one
alternative versus another.
--.
COMMENT A4-2
(Miller)
The total cost of the LDCC, with lime neutralization and
mine~rehabilitation, is $74,105,000, considerably higher
than the estimate included in the Addendum.
RESPONSE TO COMMENT A4-2
The capital cost of $74,105,000 presented in the above com-
ment uses different assumptions to derive the costs than
those used by CSMRI in the Feasibility Study Addendum.
CSMRI's assumptions were based upon their previous
experience with LDCC. . .
COMMENT A4-3
(McLean)
All of. the capital costs for Alternatives CA-8 and CA-9
exceed the average Superfund capital expenditure of $7 mi1-
lion by a factor of 5 to 20 times. Since it does not pose
any public health threat, what is the justification for
these large sums of money for implementation of these
alternatives. .
RESPONSE TO COMMENT A4-3
The expenditure of
justified based on
as well as impacts
and~aquatic life.
public funds for the cleanup of IMM is.
the extent of the environmental problem,
presented by IMM on the public welfare
89

-------
. ~..
CATEGORY AS--LIABILITY,FOR IMM PROBLEMS
COMMENT AS-l
(Miller)
will IMMI be held to the new water quality objectives pre-
sented in the FIS Addendum ,to the same degree as the EPA
alternatives should IMMI "implement its plan?
RESPONSE TO COMMENT AS-l
IMMI will be required to develop a cleanup program that
meets all applicable, relevant, and appropriate federal and
state requirements (see response to Comment 2-3). There-
fore, IMMI will be required to meet the new water quality
objectives that w~re discussed in the FS Addendum because
they are a requif,ement of the Clean Water Act.
I
I
I .
i
90

-------
CATEGORY A6--IMMI PROPOSAL
COMMENT A6-1 (Stauffer, McLean, IMMI-Arman, Miller, Davy
McKee-Morgan, Babcock, Boyer)

Why was the IMMI Recovery Proposal not evaluated in the F/S
Addendum?
RESPONSE TO COMMENT A6-1
The IMMI R~covery Proposal is being evaluated by the
Colorado School of Mines Research Institute in a separate
study. The purpose of that study is to determine the tech-
nical and economic feasibility of the IMMI proposal. The
proposal was not ~ncluded in the FS Addendum because it is
not a proposal ~A would implement. Instead, EPA is eval-
uating the IMMI proposal as a potential substitute for the
alternatives developed in the Feasibility Study. Should EPA
conclude that the IMMI proposal is adequate in all respects,
and if agreement can be reached between IMMI and EPA, then
the IMMI proposal would be implemented in lieu of and not as
part of the remedial action at the site.
COMMENT A6-2
(Davy McKee-Morgan, McLean)
Why was not the Colorado School of Mines Research Institute
evaluation of the IMMI proposal included in the F/S Addendum?
RESPONSE TO COMMENT A6-2
The purpose- of the FS Addendum was to present two additional
RA alternatives under consideration by EPA for public review
and comment. A secondary objective was to apprise the pub-
lic of the CWA requirements and the extent to 'which those
requirements would affect site cleanup. The CSMRI report is
being prepared to evaluate the IMMI proposal separately and
independently from the Superfund remedial action.
COMMENT A6-3
(Martin)
The SOLUTION to the IMM problem should be handled by IMMI.
RESPONSE TO COMMENT A6-3
EPA.wiLl allow the IMMI proposal to go forward in lieu of a
federally funded cleanup program if IMMI can meet the fol-
lowing conditions:
a.
As part of its commercial mining venture, incor-
porate an environmental cleanup program that will
meet all applicable and relevant and appropriate
federal and state requirements, including the
Clean Water Act.
91

-------
b.
....'
'c.
d.
e.
f.
g.
Conduct any bench, pilot, and demonstration tests
deemed necessary by EPA and the state to prove the
technical feasibility of the IMMI proposal.

Demonstrate that its proposal is completely sound
from a technical, economic, and environmental
standpoint.. '
Develop-a site closure plan to go into effect
immediately after the solution mining operations
have ceased.
Demonstrate it has funding in hand to design, con-
struct, and operate its commercial mining venture
and a broad environmental cleanup program.

Has a '~inancial assurance mechanism in place for
site closure operations; this must meet EPA's
approval.
Reach agreement with EPA on all technical and
legal elements and incorporate that agreement in a
legally enforceable document. .
COMMENT A6-4
(Secretary and FWS) .
The IMM proposal includes shattering the orebody using explo-
sives and recovering metals by an acid leaching process. If
the procedure becomes uneconomical, it could lead to abandon-
ment of the site in a more hazardous state than it is now
and would greatly increase cleanup costs.
RESPONSE TO COMMENT A6-4
EPA shares this concern. Prior to allowing IMMI to proceed
with its in-situ mining alternative, EPA must be assured
that the funds will be available for all post-closure ,site
cleanup activities, and that this alternative will not
create a worse (potential) environmental problem than the
one it is trying to solve.
COMMENT A6-S
(Miller)
Why does .not EPA recommend the IMMI al ternati ve which is
better in all respects than any of the EPA alternatives with
reg~rd to complete control and removal ofAMD from waters of
the United States?
RESPONSE TO COMMENT A6-S
EPA is not in a position to recormnend the IMMI alternative
as the appropriate remedy for the IMM site because IMMI has
not satisfied all of the conditions discussed in the response
A6-3 above. .
92

-------
~
CATEGORY A7--0THER REMEDIAL
ACTION ALTERNATIVES
COMMENT A7-l
(Orwig, Contini)
A mining alternative shoul~ be included in the FS.
RESPONSE TO COMMENT- A7-1
Open pit and underground mining alternatives, along with
IMMI's proposed -in-situ mining process, were considered dur-
ing the Feasibility Study and are presented on page 5-7 of
the August 2, 1985, Feasibility Study~report.
COMMENT A7-2
(Boyer)
All the combined'alternatives developed in the FS are flawed
because the orebody or the materials from its composition
are not removed from the area.
RESPONSE TO COMMENT A7~2
Total removal of the IMM orebody was considered as an alter-
native to meet ,the Clean Water ~ct. As described in the FS -
Addendum, the estimated cost for implementing this alterna-
tive was so exorbitant' it was not considered cost-effective,
and was therefore not considered further.
COMMENT A7-3
(McLean, Davy McGee-Morgan)
There is no discussion of the alternatives proposed by Stauf-
fer Chemical Company.
RESPONSE TO COMMENT A7-3
The alternatives proposed by- Stauffer Chemical Company were
reviewed. However, it was determined that some of Stauffer's
basic assumptions were not consistent with information
obtained in the Remedial Investigation, and that these alter-
natives would not meet the water quality objectives estab-
lished for the site if their assumptions had been consistent
with the ones used by EPA. Therefore, Staufferts alterna-
tives were not considered in the Feasibility Study.
CO~N~ A7-4
(Stauffer)
Stauffer has previously proposed an $8.1 million project
which would comply with water quality standards at the point
of compliance below Keswick Dam. We urge EPA to consider
this option as an alternative if the commercial mining option
is not adopted. '
93

-------
RESPONSE TO COMMENT A7-4
See response to Comment A7-3f
COMMENT A7-S
( Stauffer)
, .
Stauffer agrees with EPA "that the total removal option be
eliminated from ~urther consideration.
RESPONSE TO COMMENT A7-S
No response required.
--.
94

-------
CATEGORY A8--PREFERRED REMEDIAL ACTION
COMMENT A8-1
(Babcock, Boyer)
I strongly urge you to reject Proposals CAI-CA9 inclusive
and accept the Iron Mountain Mines Inc.-Davy McKee Inc.
proposal.
RESPONSE TO COMMENT A8-1
BecauseIMMI has not satisfied the conditions outlined in
the response to Comment A6-3, EPA is not in a position to
accept the IMMI proposal. EPA will, therefore, continue to
consider CA-8 and CA-9 as potential remedies for IMM.
COMMENT A8-2
(M-iller)
It is hoped that EPA will recognize the practicality of a
resource recovery plan, such as the in-situ mining process
proposed by Iron Mountain Mines. A proposal of this type
should merit serious consideration; particularly when costs
and sources of funding are taken into account. .
COMMENT A8-3
fContini)
I urge you to reconsider your proposals and save the tax-
payers considerable dollars by encouraging private removal
of the orebody. .
COMMENT A8-4
(Danielson)
It is my belief that Davey McKee's extraction program far
surpasses any of the other alternatives proposed in both a
financial and technical sense.
RESPONSES TO COMMENTS A8-2 THROUGH A8-4
EPA has left the door open to IMMI to come forward with a
commercial mining venture, incorporating a broad-range envi-
ronmental cleanup program, to the extent that conditions in
the response to Comment A6-3 are fully satisfied. It is
EPA's preference that PRP funds be used to clean up the IMM
site; rather than federal Superfund monies. It is EPA's
position that IMMI has had ample time to address the condi-
tions noted in Response A6-3; that, at an appropriate point,
the. Agency may need to expend public funds as cleanup funds,
if the above-referenced conditions still have not been met.
COMMENT A8-S
(Bureau)
Either CA-8 or CA-9 would produce significant benefits to
the salmon resource.
9S

-------
RESPONSE TO COMMENT A8-5
EPA agrees.
COMMENT A8-6
(Girard)
I am in favor of source management as opposed to stream man-
agement. The latter would adversely affect our land by reduc-
ing the flow in Spring Creek leaving more toxic drainage
through our property. Changing the course of the stream
goes against the history of riparian rights and water laws
in our state.
RESPONSE TO COMMENT A8-6
EPA also favors source control and treatment alternatives
but recognizes t~at stream management will also be needed to
meet project cleanup objectives. EPA will consider allowing"
the City of Redding hydroelectric project to proceed in lieu
of the Upper Spring Creek diversion if the City succeeds in
its efforts to secure approval for its project. Nevertheless,
EPA is hopeful that through the implementation of source
control and treatment alternatives that the water quality
along Spring Creek will be improved or, at a minimum, not
degraded beyond" current conditions. In fact, there should -
be no discharges of AMD to receiving waters during the dry
periods causing the possible return of certain beneficial
uses to receiving waters. Discharges of AMD during the
winter months should receive the benefit of dilution pro-
vided by rainfall in the Spring Creek basin, keeping water
quality within acceptable limits.
COMMENT A8-7
(Secretary and FWS)
We support Alternative CA;"9 as being what we perceive to be
in the best interests of the fish and wildlife.
RESPONSE TO COMMENT A8-7
No response required.
COMMENT A8-8
(Boyer and 28 Signatures on a Form Letter)
The iron Mountain Mine proposal should be implemented
because it is an environmentally and economically sound min-
ing~program which will not only solve any inferred pollution
problem, but will also boost the economy of the Redding area.
RESPONSE TO COMMENT A8-8
Please see response to Comments A8-2through A8-4.
96

-------
."
CATEGORY A9--0THER CONCERNS
COMMENT A9-1
(Davy McKee-Morgan)
Does the Superfund law apply to complete removal of mineral
resources?
RESPONSE TO COMMENT A9-l
The Comprehensive Environm~ntal Response, Compensation, and
Liability Act' (CERCLA) is the "Superfund law." The National
Contingency Plan (NCP) is the plan for implementing that
law. The plan requires that at least one alternative be
,examined, if feasible, that includes offsite disposal of
contaminants at a RCRA-approved facility.
-~,
In this case, the source of contaminants happens to be a
mineral resource. Removal of the source was considered, but
not evaluated in detail, and eventually screened because it
was infeasible with regard to costs. ' .
COMMENT A9-2
(Bureau and Secretary)
We emphasize th~ value of the'chinook salmon, steelhead trou~,
and resident trout. These provide an extensive river sport
fishery (steelhead and rainbow trout) and ocean commercial
fishery (chinook salmon)., At one time the upper Sacramento
River (Redding-Anderson) produced over one-half of the total
mainstem spawning run of fall-run chinook salmon, estimated
to exceed 200,000 spawners in the 1950's.
The estimated monetary value of the chinook salmon and steel-
head trout runs below Red Bluff Diversion Dam is approxi-
mately $33.7 ,million annually. The estimated economic value
is anticipated to increase to $72 million annually.
RESPONSE TO COMMENT A9-2
No response nec~ssary.
COMMENT A9-3
(Miller)
Why does EPA continue to develop additional alternatives for
the IMMI site?
RESPONSE TO COMMENT A9-3
The original purpose of the new alternatives presented in
the Feasibility Study Addendum were developed to identify
alternatives which comply with all the provisions of the
Clean Water Act. "
97

-------
COMMENT A9-4
(Miller)
Why were not RCRA requirements considered when the remedial
action alternatives were developed? Is it legal to ignore
RCRA?
RESPONSE TO COMMENTA9-4
The applicability, relevancy, and appropriateness of RCRA as
it applies to proposed remedial alternatives were con-
sidered, but not deemed applicable .to CA-8 and CA-9. Alter-
natives CA-l through CA-7, which were developed. during the
Public Comment FS, considered potential RCRA requirements
with regard to lime sludge disposal.
COMMENT A9-S
(Miller)
If EPA can ignore the requirements of RCRA, will IMMI be
held to complying with all provisions of RCRA should they
implement their plan? .
RESPONSE TO COMMENT A9-S
Until EPA has received and reviewed and evaluated a final
IMMI plan for its in situ, mining and site cleanup programs,-
the Agency is unable to determine whether RCRA would or
would not be applicable, relevant, and appropriate to the
IMMI operation. .
98

-------
CATEGORY AlO--PROPOSED NEW COMBINED
ALTERNATIVES CA-8 AND CA-9
COMMENT AlO-l
Two commenters (FWS and Seqretary) have indicated that based
on their analyses, Combiried Alternative CA-9 would provide
the greatest level of protection for anadronomous and resi-
dent fish resources as well as other aquatic and terrestrial
habitats important to fish and wildlife.
RESPONSE TO COMMENT AIO-l
No response required.
COMMENT AIO-2
lSecretaryL
Combined Alternative CA-9 will have a higher implementation
cost, but should result in a more reliable control system, .
less maintenance, and less chance of failure during critical
periods ~f high runoff in comparison with CA-8.
I
RESPONSE TO COMMENT AlO-2
EPA concurs with this comment.
COMMENT AlO-3
(Bureau)
Combined Alternative CA-8 could be modified to' treat the
acid mine drainage by dumping large quantities of lime or
limestone in the mines and sealing the portals. Valves
could be installed to release the treated wa~er. This mod-
ified alternative would solve the sludge disposal problem.
RESPONSE TO COMMENT AlO-3
The treatment scheme proposed in this component may be theo-
retically possible but may not be practical because of the
following aspects: .
o
In order to achieve ferrous iron removal, the iron
must be oxided to the ferric iron state. This'
could not practically be achieved with this treat-
ment scheme.
o
Metals removal is dependent on achieving the opti-
mum pH. By dumping lime into the mines, the pH
cannot be controlled. High pH water resulting
from overdosing with lime would have to be neu-
tralized prior to discharge.
99

-------
o
The lime would be continually neutralized by the
aci~mine drainage and would'have to be replaced
on a regular basis. .
o
The sludge produced would have to settle out with
the mine working~. It is quite possible that
. sludge would exit the portals, along with the
treated water.
o
There would probably not be sufficient storage of
the wet sludge within the mine workings.
COMMENT AIO-4
(Stauffer)
Combined Alternatives CA-8 and CA-9 are environmentally
unsound. CA-8 ~?uld create mountains of gypsum waste.
RESPONSE TO COMMENT AIO-4
The commenter has not discussed what aspects of CA-8 and.
CA-9 the commenter considers to be environmentally unsound.
However, EPA believes that CA-8 and CA-9 are environmentally
sound responses to the IMM problem because both these alter-
natives will minimize the metals discharging to the receiv- -
ing waters. This should improve water quality substantially
above current water quality in the immediate receiving
waters. .
For Alternative CA-8, the dry solids produced by the lime/
limestone neutralization process will be deposited in Brick
Flat Pit. .
COMMENT AIO-5
( Stauffer)
Combined Alternative CA-9 includes filling the mine workings
with low-density cellular concrete. This is an unproven
technology and a high risk option and is inconsistent with
the NCP. It is an unreasonable alternative because of the
following: .
o
Mine workings would have to be reworked before the plug-
ging operation began.

Worker safety would be significant during the rehabili-
tation of the mine workings.
o
o
- Injection of the LDCC would require installation of an
onsite plant to produce LDCC 24 hours a day for a mini-
mum of 2 years and probably more.
RESPONSE TO COMMENT A10-5
The commenter has not stated the reason for its belief that
the use of LDCC is inconsistent with the NCP and therefore,
100

-------
,.,... - . -. ;-"~-
EPA is unable to fully respond to the comment. Neverthe-
less,.the NCP states in 300.681i] .that "innovative or
advanced technology shall, as appropriate, be evaluated as
an alternative to conventional technology." LDCC is such as
technology, and it was evaluated as' an alternative to con-
ventional treatment of AMD. For this reason, EPA considers
that it has complied wit~ the intent of the NCP. The risk
associated with LDCC is not clear at this time. Prior to
making a final decision on LDCC, EPA will fully evaluate and
weigh the risks associated with proceeding with LDCC..
Rehabilitating a portion of the mine workings is a technique
commonly used in the mining industry and should not present
unusual technical and safety concerns. Also, the construc-
tion of an onsite concrete batch plant is not uriusual for
large construction projects.
.-.
COMMENT AIO-6
(Stauffer)
Neither Combined Alternative CA-8 or CA-9 is' cost~effective
while achieving its objective of protecting the public
health, welfare, and the environment. .
Some water quality improvement may be achieved by the imple-
mentation of CA-8 or CA-9; however, water quality standards -
will not be met in portions of Keswick Reservoir and surface
streams at the. site. Therefore, substantial additional expen-
ditures necessary to implement either of these alternatives
compared to Stauffer's recommended remedial action or previous
alternatives developed by EPA cannot be justified under cost-
effective requirements of the. NCP based on questionable and
marginal improvements in stream quality.
RESPONSE TO COMMENT AlO-6
EPA has determined that Stauffer's recommended remedial
action is incapable of meeting site cleanup objectives, will
not meet all applicable, relevant, and appropriate require-
ments, and therefore not comply with the requirements of the
NCP. For these reasons, this alternative does not warrant
further consideration as a potential remedy for the IMM
site. Alternatives CA-l through CA-7 are not considered to
be cost-effective responses for various reasons including-
cost, ability to meet primary and secondary cleanup objec-
tives, and ability to comply with the Clean Water Act.. At
this ti~e, EPA is. unable to make a final cost-effectiveness
determination for CA-8 and CA-9 because the Agency must' .
first determine the technical feasibility and implementabil-
ity of LDCC at IMM. In the interest of expediting response
actions at IMM, EPA has chosen to select and implement the
components common to both CA-8 and CA-9, as well as the
partial cap, while the Agency evaluates the LDCC remedial
technology. Following this evaluation, EPA will determine
the cost-effective remedy and, thus, the final scope of the
response for IMM. .
101

-------
COMMENT AlO-7
(Stauffer)
CQmbined Alternative CA-9 using LDCC is inconsistent with
the requirements of the NCP. Since the NCP emphasizes the
use of established technology and requires the use of the
lowest cost alternative that is technically feasible. The
FS Addendum acknowledges that LDCC is unproven technology
and it costs more than any other alternatives presented that
are technically feasible.
RESPONSE TO COMMENT AlO-7
LDCC is an unproven technology for application at mining
sites similar to IMM with AMD problems. Section 300.68
(h) (2) (v) of the NCP states that the detailed analysis of
alternatives should include an analysis of whether other
advanced innovatIve or alternative technologies are appro-
priate to reliably minimize or prevent a future threat to
the public health or welfare and the environment. Sec-
tion 300.68(h) (3) further states that in performing the
detailed analysis, it may be necessary to gather additional
data to complete the analysis. EPA has therefore chosen to
conduct pilot and demonstration tests to determine the tech-
nical feasibili~y and implementability of LDCC at IMM.
Although LDCC appears to cost more than other alternatives
(during the 30~year project period), the cost of CA-9 may,
in fact, be less for reasons discussed in the FS Addendum
and when considering that the remedial response to the
release of AMD can continue in perpetuity. Therefore, if
LDCC succeeds in eliminating or significantly reducing the
formation of AMD to the point where treatment will not be
required in perpetuity, there would be a substantial cost
savings realized in proceeding with LDCC over th~n other
remedial action alternatives that include treatment.
COMMENT A10-8
(Miller)
Combined Alternatives CA-8 and CA-9 are of highly dubious
long-term effectiveness since they do not involve proven
technology as applied at similar sites and environmental
circumstances.
RESPONSE TO COMMENT AlO-8
Combined Alternative CA-8 contains treatment, water manage-
men~, and source control alternatives which are proven tech-
nologies. The only component of Alternative CA-9 for which
the effectiveness cannot be predicted is filling the under- .
ground workings with LDCC. As explained in the FS Addendum,
major exploratory programs and pilot studies would be
required before EPA decides to proceed with full-scale
implementation of LDCC.. .
102

-------
----C:;;-;'-r,..":;-"F-;;"- --
COMMENT AIO-9
(Miller)
Filling the mine work~ngs with concrete is totally absurd.
It disregards the $600 million value of the ore reserves at
Iron Mountain. It is incredible that this alternative
(CA-9) not only seems to be preferred, but is also suggested
as a prototype for use at other mining operations.
RESPONSE TO COMMENT AIO-9
The LDCC will only be used to fill areas that have been pre-
viously mined out. This should have no effect on mining the
remaining ore through conventional mining methods at a time
when it becomes profitable. EPA is not now considering LDCC
as a prototype because certain unanswered questions- remain
about its technical feasibility. However, if it is found to
be feasible, it-~~ould serve-as a prototype to address.
prob~ems similar to IMM at other National Priority List
mining sites.
COMMENT AIO-IO
(IMMI-Arman)
The- sludge generated by the lime neutralization plants would
be a greater problem than the original acid mine drainage.
. -
RESPONSE TO COMMENT AlO-lO.
The acid mine drainage discharged from Iron Mountain Mine
has been documented to be responsible for fishkills in the
Sacramento River. This is the existing problem. The sludge
produced by the lime/limestone neutralization plants will
remove the metals which wculd have been discharged to the
receiving waters. Proper handling of this sludge will pre-
clude metals from being discharged and should not present an
environmental problem.
COMMENT AlO-ll- (Stauffer)
Combined Alternatives CA-8 and CA-9 increase the projected
costs of remediation from previous excessive levels to the
exorbitant and wasteful range of $50 million to $70 million.
These options are grossly inconsistent with the NCP as they
are beyond any possible argument that they meet the require-
ment-of cost-effectiveness. .
RESPONSE TO COMMENT A10-Il
Cost is only one factor that the NCP directs that must be
considered in the selection of a remedy: other factors
include technology, reliability, administration,' and other
concerns. While the projected cost of remediation is high,
EPA does not consider the cost to be exorbitant when taking
into account the unique nature and extent of the IMM
103

-------
proble~. The cost to the government in taking a remedial
response action should be offset by increased revenue to the
U.S. Treasury through" the sale of Shasta Lake waters for
authorized uses that would have been used to abate the IMM
problem. The USBR has apprised EPA that between $9 million
and $32 million is lost annually from the U.S. Treasury for
this purpose. At this rate, the payback to the government
in taking remedial action at IMM should be on the order of
2; to 8 years. - In this context, the cost of Superfund
remediation gives the appearance of being a most reasonable
expenditure.
-.
104

-------
CATEGORY All--COMMENTS RELATING TO
COMPONENT ALTERNATIVES
COMMENT All-l
(IMMI-Arman)
The injection of LDCC into,the underground mine workings
will destroy future mining of the ore bodies.
RESPONSE TO COMMENT All-l
The use of LDCC will not necessarily preclude conventional
underground or open pit mining of the orebody. The only
areas that would be filled or lost are those which are mined
out already. In fact, LDCC could enhance underground mining
by providing additional support in the existing adits and
crosscuts. Areas which have not been previously mined will
not be filled with LDCC. Thus, the new ore can be access-
ible to conventional mining technologies.
COMMENT All-2
(IMMI-Arman)
It 'is not possible to create a permanent bond or seal
between LDCC and the massive sulfide to keep underground
seepages from ~lowirtg. How will LDCC be bonded to loose an~
powdery sulfate material located 200 to 400 feet below sur-
face level?
RESPONSE TO COMMENT All-2
The LDCC material which is proposed has been used in several
tests' to extinguish burning coal and to pillar walls in an
underground copper mine and appears to bond and seal very
well. In addition, the low viscosity of the material will
permit encapsulation of rubblized rock and ore in the mine.
The exact formulation of the material and handling proper-
ties will be'developed during the test phase of the project.
COMMENT All-3
(IMMI-Arman)
How will the underground workings be filled?
RESPONSE TO COMMENT All-3
To date, LDCC has been injected into mined out cavities from
sur~ace drill holes for subsidence control. If LDCC is the
selected alternative at IMMI, drill hole and underground.
placement will be evaluated during final design.
COMMENT All-4
(IMMI~Arman)
After LDCC is injected into the mine workings, what will
prevent the "reactive forces of nature" from creating seep-
ages in the future?
105

-------
RESPONSE TO COMMENT All-4
.~.'
The injection of LDCC. into the mine working is designed to
raise the groundwater table to premining conditions and encap-
sulate rubblized massive sulfide ore. LDCC will also add
substantial neutralization reagent underground if "reactive
forces of nature" create new conditions at IMM. Also LDCC
is only a portion of the total remedial action. The other
ones, such as capping will prevent most surface water from
entering the mine workings.
COMMENT All-5
(IMMI-Arman)
What is the basis of the 85% effectiveness for the LDCC
alternative?
RESPONSE TO COMMENT All-5
The 85 percent effectiveness for the LDCC alternative was
arrived at by considering several factors. These included
encapsulation studies conducted on broken/rubblized coal
piles to extinguish coal mine fires, complete cavity fill
for subsidence control at a site in Wyoming, and adhesion
.studies of LDCC on pillars for air wall control in an under-
-ground mine. I~ addition, access and size of the area to be-
filled were weighed and examined~ Based on the above fac-
tors, it was concluded that LDCC could be 80 to 90 percent
effective.
COMMENT. A11-6
(Rardin)
We obtain our water (drinking and agricultural) from Flat
Creek.
RESPONSE TO COMMENT A11-6
During the remedial investigation, a survey was conducted to
determine if the residences along Flat Creek were using water.
which could possibly be contaminated by runoff from the Min-
nesota Flats tailings pile. At that time, no residences
were identified that were using Flat Creek water. Water in
Flat Creek below Minnesota Flats exceeds the EPA Safe Drink-
ing Water Standards for cadmium, copper, iron, and man-
ganese. If Alternative CA-9 is implemented, the Minnesota
Flats tailings pile may be removed. This should improye the
wat~r quality in Flat Creek. '. .
COMMENT All-7
(Miller)
For the Upper Slickrock Creek Diversion, why does EPA recom-
mend this alternative which does not have identifiable quan-
tifiable benefits?
106

-------
..~ t .
. ,i,;.
RESPONSE TO COMMENT A11-7
As,shown in Tables 7-4 and 7-5 of the Feasibility Study Adden-
dum, the Upper Slickrock diversion will reduce uncontrolled
spills from Spring Creek Debris Dam. This is an identifiable
and quantifiable benefit.
COMMENT A11-8
(Miller)
If the lime neutralization process is implemented, how will
the dewatered sludge be placed in Brick Flat Pit so that it
evenly covers the open pit?
RESPONSE TO COMMENT A11-8
The dewatered sludge will be dumped at one edge of Brick
Flat Pit. It w~~l then be spread to allow drying during
non-rainfall conditions. Once the sludge is dried, it is
expected that the material will support heavy equipment.
COMMENT Al1-9
(Miller)
Persons who prepared the Component Alternative Summary
Table 7 apparently overlooked the following Negative Issues:
Component Alternative
Additional Negative Issues
SOURCE CONTROL
Partial Capping
(a) Creates an area subject to
wind erosion and dust
formation.
(b) De~reases time of concentra-
tion which results in faster
surface runoff contributing to.
increased downstream runoff.
(c) Increases runoff resulting in
increased erosion and
flooding.
(d) Could produce more sediment-
and carry more heavy metals
directly into receiving.
waters.
Complete Capping
(a) The same as those listed in
Partial Capping only to a
greater degree.
(b) Extremely difficult construc-
tion problem on steep slopes;
may require benching and major
earth moving effort. .
107

-------
Groundwater
Interceptioz;_.
Low Density Cellular
Concrete
(c) A temporary measure subject to
losing seal by earth movement
(earthquakes) as well as frac-
turing by alternate freezing
and thawing, etc.
.' (d) Although considered a proven
technique by the authors, a
question arises as to whether
it is proven on terrain and
soil conditions similar or
equivalent to those at Iron
Mountain.
(a) Although the author(s) admit
that this approach is not.
proven in this type of appli-
cation, our experience
suggests a low level of effec-
tiveness because there is no
aquifer or no defined water
table. Would only intercept
water moving through cracks
and fissures into the new
tunnels.
(a) Rater adequately covered the
possible shortcomings of this
technology with the exception
of any thought being given to
the destruction of about $400
million of valuable strategic
natural resources and compen-
sation therefor.
(b) The ~ext of the report sug-
. gests that one of the prin-
cipal purposes of this
treatment will be to raise the
water level above the orebody.
In the highly fractured area
in which the mine is located,
the practicality of doing this
is questioned. New seeps will
develop with AMD beIng pro-
duced therefrom. A result of
not accomplishing this will
mean the continuing breakdown
of the orebody throughout its
contact interface with the
massive concrete (LDCC) plug.
Should this occur, AMD will
continue to flow from the
mine.
108

-------
.... t,.' .:,
--.
WATER MANAGEMENT
. South Fork Spring
Creek Diversion
Upper Spring Creek
Diversion
With these possibilities in
mind, it is plain to see why
the EPA proposal was so well
weasel worded ~hat all Redding
chickens went south; i.e.,
assumed effectiveness; could
rank; still difficult to
accurately predict its effec-
tiveness; if fully successful;
etc.
(c) The question is then raised as
to why EPA is even considering
such an experimental untried
gamble with Superfund monies
when IMMI is proposing to use
completely tried and proven
techniques which will work and
do a far superior job than any
of EPA's fairy tales and. the
IMMI plan is to use private
capital to do so.

It almost appears to be just
the insane desire on the part -
of State and Federal Govern- .
ment to spend Superfund
dollars, thereby propagating
their own jobs. As a citizen
and taxpayer, I object to this
Government foolishness. The
chances of EPArecovering its
money from the owners, past or
present, is extremely remote.
In fact if the plan to fill
the mine with (LDCC) concrete
were to be implemented, EPA
may have to settle with the
owner for confiscation of a
property with a resource
valued at more than four times
the cost of the remedial
actions. .
(a) The report quite correctly
cites that this alternative
feature cannot be evaluated as
to its accomplishments~
(b) Once again, the report avoids
making any claims with respect
to the accomplishments of this
component, calling it unknown.
109

-------
~oth ot the above ~lternative components were identified as
having best cost-benefit ratio. Again, cost-benefit needs
to be quantified using finite numbers in the benefit column
not a relative rating. The benefit needs to be positively
identified: i.e., salmon directly traced to being saved by
the alternative plan component, then the value of each sal-
mon, etc. Benefits need"to be primary, not secondary. The
use of this type.of wording in the report opens the door to
the use of benefit values that can be claimed in accordance
with the Water Resources Council Guidelines used for other
federally funded or cooperative (cost-sharing) projects.
Upper Slickrock
Diversion
.-.
(a) Once again, the report fails
. to include a prediction as to
the effectiveness of this.
alternative~ More speculation
on the part of EPA. Why rec-
ommend something that cannot
have identifiable quantifiable
benefits?
TREATMENT
Lime Neutralization
(a) The process is proven; how-
ever, the process generates a
perpetual toxic waste problem
far greater than the AMD,
which can be cleaned by the
IMMI plan.
(b) Proposals within the plan call
. for the sludge to be dried to
40 percent moisture content,
then transported to the Brick
Flat Pit. A barrier across
the entrance to the pit would
be needed and the pit walls
and floor would be lined, pos-
sibly a double membrane with
subsurface drainage to comply
with RCRA. A question is
raised as to how this very
moist material is to be placed
so that it evenly covers the
open pit. The material is too
dry to flow and too wet to
support earth moving equip-
ment. This, of course, only
applies to the first year
operations. From then on, the
question becomes more
involved. When it rains, the
110

-------
----------.r
sludge is rewetted, the mois-
ture content is raised above
40 percent~ and, although a
crust may form during summer
months, the stability and
bearing strength becomes less~
hence, there is no opportunity
to use equipment. A new, very
treacherous hazard is formed;
someone stepping on the crust
and dropping into a quagmire
similar to quicksand, which is
toxic. Not a pleasant situa-
tion being mandated and per-
petuated by EPA.
--,
(c) A second hazard exists--as the
pit fills by some magic means
not yet described by EPA, and
as successive years of rain-
fall fill the reservoir with
sludge that could flow. What
happens if a major earthquake
'strikes this area? Will the,
embankment hold, or will it b~
breached under possibly less
than worst case conditions? A
breach would release a slug
flow of toxic material which
would flow down the hill, then
down Boulder Creek, wiping out
everything in its path and
ultimately flowing into the
Sacramento River above Keswick
Dam, possibly causing a wave
which could breach or overtop
Keswick Dam, causing very
serious and devastating flood-
ing. Flooding with water and
sludge polluted by all the
toxic substances accumulated
at the Brick Flat Pit plus,
possibly, all of the materials
accumulated at the Spring
Creek Debris Dam, does not
paint a pretty scene. And to
think that EPA is proposing
such an alternative!
RESPONSE TO COMMENT A11-9
Partial Capping
a.
It is not anticipated that wind erosion will be a sub-
stantial problem. However, measures to prevent, reduce,
111

-------
0; mitigate wind erosion and dust are a deta~l which
will be addressed during the final design of this
alternative.
b.
"Decreasing the time of concentration could increase or
decrease the peak flow downstream once it i~ combined
with receiving waters.' The affects of this change in
runoff are a detail which will be addressed during
final desig~. .
c.
Any potential increase in erosion from increased runoff
will be addressed during the final design.
It is unlikely that increased runoff into the receiving
waters would carry more heavy metals than would be .
reduced by preventing the migration of these waters
through thef~.orebody. However, this will be considered
during final design.

Complete Capping
d.
a. . See above answers.
b.
We agree that there will .be a substantial earthmoving
operation to construct the complete cap. However, the -
actual areas to be capped will be reviewed during the
final design. Some very steep areas (e.g., north face
of Brick Flat Pit) will likely not be covered. This is
not expected to significantly influence the effective-
ness of the total cap. The runoff in these steep areas
is high at present, and therefore a cap will not reduce
the infiltration as much as in the flatter areas.
c.
The final design of the cap will consider the freeze-
thaw and earth movement potential. Earthquakes causing
significant permanent ground displacement are not con-
sidered to be a serious problem in the capped area.
Other earth movements associated with continued caved
ground formation will be included in the design criteria.
d.
. .
The report states for SC-3,"This method uses conven-
tional materials, equipment, and construction techni-
ques applied in an innovative manner." There is no .
. 'claim that this method has beert performed on terrain or
soil conditions simil~r to those at Iron Mountain.Mine.
. Howeve~, the construction methods are conventional, and
the construction of Brick Flat Pit indicates steep tem-
porary cuts for the benches are possible.
Soil cement (SC-4) has been placed on slopes steeper
than 3:1 (horizontal to vertical). Many pond and res-
ervoir embankments have soil-cement as an erosion pro-
tection membrane. .
The terrain and soil conditions will be considered in
the final design of the cap.
112

-------
. "" ~H ""'
, ','
Groundwater Inter~eption.. .

,.-" .
Dewatering of mine wOTkings by tunnels for the purpose of
hydrological isolation is a proven technology. Some exam-
ples known to us include: the Yerington Pit in Yerington,
Nevada: the Bouganville deposit in Papua, New Guinea: and
the Twin Buttes Pit near-Tucson, Arizona.
The tunnels (collection galleries) will intercept flow mov-
ing in open fractures and joints and convey water inter-
cepted in long holes drilled from the tunnels. The orien-
tat ion and length of the long holes can be varied to
maximize the effectiveness in intercepting groundwater flow
toward the workings.
Low-Density Cellular Concrete
-~.
No natural resources will be destroyed: conventional mining
activities can take place in ore containing areas. In addi-
tion, the $400 to $600 million, figure appears to represent a
value in the ground, not a net present value of the
res,ource.
The suggested purpose of LDCC is to reestablish the original
groundwater table and prevent further oxidation of the mas- -
sive sulfide through encapsulation of the rubblized areas.
New seeps may develop, but if the surface or groundwater
does not come in contact with ore, AMD will not form.
Also, this is the very same problem envisioned with in situ
leaching. If a reservoir of AMD is created in the mine
(highly fractured), it could also leach out and cause
environmental problems.
Water Management

T~bles 7-4 and 7-5 of the Feasibility Study Addendum present
data which show that both the Upper Spring Creek diversion
and the South Fork Spring Creek diversion will reduce spills
from Spring Creek Debris Dam. These spill reductions would
be the major beriefits of these two surface water diversions.
As shown in Tables 7~4 and 7-5, the Upper Slickrock Creek-
diversion is expected to reduce the metals leaving the IMM
site~ This reduction would be the benefit of this div~rsion.
Treatment
The lime/limestone neutralization process does produce a
large quantity of sludge. If this sludge is properly han-
dled, it should present no environmental problem.

The lime/limestone sludge would be dewatered to approximately
40 percent solids and then dumped in Brick Flat Pit. The
113

-------
sludge. would be spread and allowed to dry. The sludge would
then be graded to slope such that any rainwater would runoff
to a low area from which the runoff would be continuously
removed by pumping.
The retaining wall which .will be installed at the entrance
to Brick Flat Pit would be designed to withstand earthquakes
expected in the IMM area. Even if the retaining wall should
fail, the sludge in Brick Flat Pit will be relatively dry
and" not be fluid. Thus, it should not flow into Slickrock
Creek and cause the sequence of events described in this
comment.
COMMENT AII-IO
(Contini)
Plugging and capping the Iron Mountain property is not fea-
sible because it will cause the acid mine drainage to sur-
face elsewhere.
RESPONSE TO COMMENT AII-IO
Both the partial and complete capping would prevent the
direct inflow of surface water runoff into the underground
workings. Capp~ng should not cause AMD to surface else-
where. The injection of LDCC into the mine workings is
designed to raise the groundwater table to premining con-
ditions and encapsulate rubblized massive sulfide are. LDCC
will also add substantial neutralization reagent under-
ground. It is possible that filling the underground work-
ings with LDCC may cause groundwater to surface elsewhere.
However, depending upon the effectiveness of the LDCC in
preventing the formation of AMD, the quality of these seeps
mayor may not be relat'~vely free from AMD.
COMMENT All-II
(Bureau)
At a future date, the useful life span of the Spring Creek
Debris Dam should be determined as well as the amount of
sediment that will be deposited in the reservoir.
RESPONSE TO COMMENT All-II
The U.S. Bureau of Reclamation is currently responsible for
the useful life of Spring Creek Debris Dam. The implemen-
tation of the remedial action should not have a significant
effect on sediment deposition in the reservoir.
COMMENT All-12
(Bureau)
The capping and diversion alternatives provide the greatest
cost benefit. And we support the phased approach to
implementation.
RESPONSE TO COMMENT All-12
EPA appreciates the Bureau of Reclamation's support.
114

-------
COMMENT AII-13
(Bureau, FWS)
We do not believe that partial or complete capping will
result in significant environmental concerns with respect to
vegetation and wildlife.
RESPONSE TO COMMENT All-i3'
No response necessary.
-~.
115

-------
..-.,
CATEGORY A12--COMMENTS RELATED TO THE
CLEAN WATER ACT
COMMENT A12-1 (Stauffer)
EPA has added remedial A~ternatives CA-8 and CA-9 based on
Clean Water Act standards 'including (i) BAT effluent. limit a-
tions for all pollution sources at Iron Mountain Mine, and
(ii) ambient water quality criteria applicable to the Sac-
ramento river and its tributaries. EPA justifies these
additions on the ground that the NCPrequires identification
of alternatives that meet or exceed all "applicable or rele-
vant" environmental standards.
The NCP, however, clearly specifies that applicable and rel-
evant standards Mill be evaluated and "identified for the
specific site." 40 CFR Section 300.68(i). Likewise, th~
preamble to the NCP "reemphasizes that the determination and
implementation of applicable and relevant and appropriate
requirements will be made on a case-by-case review is espe-
cially critical when applying Clean Water Act standards
which are themselves based on complex, case-by-case analy-
.sis. Yet the FS Addendum fails even to acknowledge the
diverse issues which the Agency will need to resolve before -
it can determine whether particular Clean Water Act stan-
dards should be deemed applicable or relevant to the Iron
Mountain Mine site. These unresolved issues include at.
least the following:
o
To the extent the acid mine drainage at the site
has nonpoint sources, it is not appropriate to
apply technology-based effluent lim~tations issued
for point sources under the Clean Water Act. The
Clean Water Act recognizes that nonpoint sources
are not amenable .to technological solutions;
instead they require site specific management.
practices or land use controls. Nonpoint source
pollution is addressed by area wide water quality
management plans developed under Section 208.

To the extent the acid mine drainage has nonpoint
sources, site-specific, water-quality-based eff~u-
ent limitations are also not be appropriate. Under
the Clean Water Act scheme for nonpoint sources,
water quality standards are taken into account on
a regional basis in the Section 208 plans. They
are not, as a general rule, f~ctored into the
requirements for an individual source. In this
fashion, the pollution from all sources in an area
can be taken into account in developing nonpoint
source pollution control requirements.
o
116

-------
~ ----------- -----;c-
. .
.~' ".'
().,
To the extent the discharge from the mine has point
sources, existing effluent limitations, e.g., for
the iron. ore subcategory of the ore mining and
dressing point source category, 40 C.F.R. Part 440,
. are not appropriate either. Those standards apply
to "discharges from (a) mines operated to obtain
iron ore, regardless of the type of ore or its
mode of occurrence," 40 C.F.R. Section 440.10
(emphasii added). They do not apply to inactive
mines and were not based on a consideration of
conditions associated with inactive mines.
Rather, EPA based the standards on a study of
waste water generation at operating mines, 47 Fed.
Reg. 25683, 25688 (1982), where pollution control
measures may be achievable more efficiently than
. in an abandoned mine.
.~.
o
If a discharge under the Clean Water Act is a non-
point source, but technology-based effluent limi-
. tations which have been promulgated are not
applicable, effluent limits normally are based on
"best professional judgment" ("BPJ"). To the
extent that effluent limitations based on BPJ are
appropriate here, they should take into account a
variety of technologi~al and economic considera- -
tions for toxic and nonconventional pollutants.
BPJ standards reflecting the best available tech-.
.nology economically achievable. ("BAT") should take
into account the technology, cost, and other fac-
tors identified in Section 304(b) (2) as well as
the economic impact factors applicable in Sec-
tion 301(c) variances. BPJ standards for conven-
tional pollutants (~, total suspended solids,
biochemical oxygen demand) reflecting "best con-
ventional pollutant control technology" ("BCT"),
should take into account the cost reasonableness
tests contained in Section 304(b) (4) (B). It is
unclear how these factors might appropriately be
applied in calculating BPJ effluent limitations
for the Iron Mountain Mine site.
o
If promulgated Clean Water Act Effluent limita-
tions are otherwise appropriate for the site, a
Section 301(c) economic impact variance might
s"till be available if the economic impacts of com-
pliance are excessive1 but in fact, there are no
applicable standards.
o
To the extent the mine discharge has point sources,
water-quality-based effluent limitations may not
be appropriate for reasons similar to those dis-
cussed above with regard to nonpoint sources. If
there are other sources of pollution of the stream
117

-------
...'
segment affected by the mine's discharge, includ-
ing nonpoint sources from the Iron Mountain Mine
site or other upstream sites, it would be appro-
priate to perform the water quality analysis on a
regional basis.

In assessing the water quality impacts of the mine
discharge, it would be appropriate to define a
reasonable "mixing zone~ in the receiving waters.
o
COMMENT A12-2 (Stauffer)
This is an improper application of this requirement. Accord-
ing to the Clean Water Act, BAT must be applied to these
process streams and point source 4ischarges for which effluent
limits have bee~_.established after careful studies have been
completed. None have been established for acid mine drainage
for inactive mine sites. Water quality cr~teria should there~
fore be established on a cost-effectiveness/case-by-case
basis.
RESPONSE TO COMMENT A12-1 AND A12-2
Stauffer Chemical Company submitted extensive comments con- -
cerning the Clean Water Act. The Feasibility Study Addendum
presented two new combined alternatives, CA-8 and CA~9, which
contain pollution control components aimed primarily at reduc-
ing or eliminating the discharges for the two copper cementa-
tion plants onsite~ These plants are the greatest sources
of pollution at Iron Mountain, discharging acid mine drainage
containing up to 3 tons of toxic heavy metals per day at
pH's that have been measured below one standard unit. Among
the major applicable goals of the Clean Water Act is the
elimination of the discharge of pollutants to surface waters.
Stauffer would argue that a cleanup alternative such as its
own $8.1 million proposal, which allows the continued
untreated discharge from the plants, is conceivably justifi-
able under the Clean Water Act. EPA strongly disagrees.
As stated in the Feasibility Study Addendum, Section 301 of
the Clean Water Act requires that discharges from point.
sources, such as the cementation plants, meet both technology-
based pollution control effluent limitations, arid any more
stringent limitations necessary for achieving compliance
with water quality standards. One of Stauffer's repeated
con~entions is that water quality standards should be
neglected at all points above Keswick Dam. The water qual-
ity standards that apply below Keswick Dam clearly apply to
all tributary streams above it, including Boulder, Slick-
rock, Flat, and Spring Creeks. The numeric and narrative
standards are listed in the Addendum, and are a part of both
state and federal law. .
118

-------
EPA ha$ determined using Best Professional Judgment that
effluent limitations achievable~using lime treatment and
settling technology satisfy the technology-based pollution
control requirements of the Act. This technology will raise
the discharge pH ,from about 1-2 to approximately 6-9, and
will at minimum achieve m~ximum concentration limits of
0.3 mg/l copper, 1.5 mg/l zinc, and 0.1 mg/l cadmium. Maxi-
mum concentrations discharged from the copper cementation
plants during the Remedial Investigation were 2 to 3 orders
of magnitude above these limits:
o
o
o
III mg/l copper
1,270 mg/l zinc
8.9 mg/l cadmium
Stauffer has presented many generalized arguments concerning
the Clean Water,,,"..Act without relating them to any specific
sources of pollution, or receiving streams, at Iron Mountain -
Mine. It is therefore difficult to ascertain the point of
several of these arguments. Summaries of issues raised in
the discussion on pages 3 to 5 of Stauffer's letter and EPA
responses follow.
o
Technology-based limitations should not be applied
to nonpoint sources of acid mine drainage.
EPA has not applied technology-based limitations
to any nonpoint sources, and Stauffer has failed
to identify any nonpoint sources at Iron Mountain
Mine. The copper cementation plants are clearly
point sources. Although many sources of pollu-
tants such as waste dumps are commonly referred to
as nonpoint sources, they are in fact point sources
for the purposes of the Clean Water Act.

Water quality-based effluent limitations should
also not be applied to nonpoint sources.
o
Again, without a particular reference to a non-
point source, the point of this argument is unclear.
o
Promulgated EPA effluent guidelines such as those
for the Iron Ore Subcategory of the Ore Mining 'and
Dressing Point Source Category should not be applied
to point sources at inactive mines.
As stated above, EPA established using Best Pro-
fessional Judgment that effluent limitations
achievable using lime treatment and settling meet
the technology-based requirements of the Act.
Even if the mine were active, EPA questions
whether the Iron Ore Subcategory guidelines would
be applicable.
119

-------
. ~..
If a discharge under the Clean Water Act is a non-
point source, but EPA-promulgated effluent limita-
tions are not applicable, effluent limitations
normally are based on "best professional
judgment."
6
Again, it is not'possible to respond to this issue
without a. specific reference to a nonpoint source
of pollution at the site.

Water quality-based effluent limitations may not
be appropriate for point sources if there are other
sources of pollution of the stream segment affected
by the mine's discharge including nonpoint sources
at Iron Mountain Mine and other upstream sites..
EPA dt~agrees. Water quality-based effluent limi-
tations are appropriate to point sources, and may
in fact become more stringent if other sources of
pollution affect a stream segment. In this case,
Iron Mountain Mine is the only source of pollution
on Boulder and Slickrock Creeks. Iron Mountain is
by far the largest source of pollution on Spring
Creek, and the one other known source is under a
Regional Board Order to Cease discharge.
o
In assessing the water quality impacts of the mine
discharge, it would be appropriate to define a
rea~onable "mixing zone" in the receiving waters.

The receiving waters of the copper cement plants
are Boulder and Slickrock Creeks. Although the
Calif6rnia Basin Plans contain no provisions for
mixing zones, EPA typically calculates the avail-
able dilution using a stream's 7Q10. In the case
of Boulder Creek, this might allow a small mixing
zone. Slickrock Creek, however, is intermittent
. and no mixing zone would be allowable.
120

-------
I'
_. - -. -
.....-....-- --'..~_..
...,
.-= --':;"';' _:.- '...,:;........... ',"-:;-."", ~.'
CATEGORY A13--COMMENTS RELATED TO ,
,.', '..o~:=-" ,'POINT OF' COMPLIANCE -'=,~~-~--~C"---~-~"'--'-- - ,
COMMENT A13-1 (Stauffer)
.. .
EPA adopted combined alternatives upon belief they must aban-
don the point of compliance concept presented in the Public
Comment FS submitted in August 1985. This provided for com-
pliance in the Sacramento River just below Keswick Dam. Now
EPA asserts they must impose the most rigorous controls
upstream from Keswick Dam to meet the requirements of the
Clean Water Act and the requirement of Best Available Tech-
nology Economically Achievable. This interpretation is
entirely wrong.

The desiqnation'~f a point of compliance with water quality
standards at a point in the Sacramento River continues to be
justified.
RESPONSE TO COMMENT A13-1
EPA to answer.
COMMENT Al3-2 (Miller)
What are the specific new objectives established by EPA, in
the FS addendum, in terms of finite numbers?
RESPONSE TO COMMENT Al3-2
EPA's new secondary objective is to develop a cost-effective
remedy that will minimize the discharge 0 f me,tals from the
IMMI s:ite into the receiving waters. There are no finite
numbers, and this objective will be used only on a relative
benefit basis when comparing one alternative versus another.
RD/R89/014
121

-------