Environmental Protection Agency
Office of Enforcement
EPA-330/2-77-006
6EOHYDROLOGIC CONDITIONS IN THE VICINITY OF
BUNKER HILL COMPANY WASTE-DISPOSAL FACILITIES
Kellogg, Shoshone County, Idaho - 1976
Jim V. Rouse
March 1977
National Enforcement Investigations Center
Denver, Colorado
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CONTENTS
I INTRODUCTION 1
II SUMMARY AND CONCLUSIONS 4
III RECOMMENDATIONS 6
IV SITE DESCRIPTION 7
Geology 7
Valley History 8
Bunker Hill Pond Construction History . . 9
Effect on Receiving Water 17
V RESULTS OF INVESTIGATION 19
Stratigraphy 20
Ground-Water Movement and Contamination . 20
VI TAILINGS DAM TECHNOLOGY 37
REFERENCES 46
APPENDICES
A RECONNAISSANCE VISIT
B CHAIN OF CUSTODY PROCEDURES
C DRILL LOG OF BUNKER HILL AREA
OBSERVATION WELLS
TABLES
1 Ground-Water Depth and Elevations .... 23
2 Results of Fluoride Analyses 27
3 Results of Zinc Analyses 29
4 Results of Cadmium Analyses 31
5 Results of Lead Analyses 32
6 Results of Iron Analyses 34
7 Results of Manganese Analyses 35
FIGURES
1 Sketch Map of Sept. 2, 1954 10
2 Sketch Map Showing Bunker Hill Pond
Area Oct. 25, 1958 12
3 Sketch Map Showing Bunker Hill Pond
Area Oct. 28, 1968 14
4 Location of Bunker Hill Area Observation
Wells and Direction of Ground-Water
Movement 21
5 Mean Fluoride Concentrations in Bunker
Hill Observation Wells 26
6 Mean Zinc Concentrations in Bunker
Hill Observation Wells 30
m
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I. INTRODUCTION
The Bunker Hill Company and its predecessors have operated a mine-
mi 11 -smelter complex in the Kellogg, Idaho area for almost a century.
Initially, all liquid and solid residues from the operation were dis-
charged into the South Fork Coeur d'Alene River. These practices grad-
ually changed due to environmental concern and the desire to retain mill
solids (tailings) for reprocessing at a later date in the event of
improved recovery technology.
The first materials which were retained consisted solely of mill
tailings discharged into a tailings pond, and lead smelter slag deposited
on the flood plain of the South Fork Coeur d'Alene River north of the
Bunker Hill facility. With time, the tailings pond received other solid
waste, including byproduct gypsum from a phosphoric acid plant, together
with liquid discharges such as acid mine drainage and lead smelter, zinc
plant, and phosphoric acid plant effluents. The result was the gradual
evolution of a 160-acre tailings pond, gypsum pond and slag pile which
rises above its surroundings on the flat flood plain of the South Fork
Coeur d'Alene River Valley. As the height of the tailings pond in-
creased, the ground-water gradient between the pond and the river in-
creased, which caused an ever-increasing rate of seepage from, .the pond
into the stream. As the upstream receiving water quality was enhanced
through pollution control measures, the effect of the seepage became
increasingly apparent.
The Environmental Protection Agency (EPA) Region X office discussed
this leakage with Bunker Hill Company and requested the construction of
observation wells around the toe of the pond as a condition for the
issuance of the Bunker Hill National Pollutant Discharge Elimination
*
System (NPDES) permit. The observation wells were constructed by Bunker
Federal Water Pollution Control Act Amendments of 1972.
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Hill Company, as required, but they were not adequate to provide suf-
ficient information on the seepage. Information in Company files indi-
cated that Bunker Hill Company recognized the presence and feasibility
of control for seepage as early as 1967, but none of these measures were
implemented.
At the request of Region X, EPA, the U.S. Attorney for the District
of Idaho filed suit in District Court on Sept. 2, 1975 to prohibit
Bunker Hill from discharging unpermitted pollutants from its facilities
into waters of the United States. EPA Region X requested technical
support to aid in this case from the National Enforcement Investigations
Center (NEIC). A meeting was held between EPA Region X and NEIC person-
nel on May 22, 1975, to discuss the scope of this technical support.
EPA had considerable information to indicate that leakage from the
tailings pond was entering the South Fork Coeur d'Alene River. Region X
requested NEIC to conduct a geohydrologic investigation in the vicinity
of the tailings pond and gypsum pond, to provide additional information
on the areas and modes of seepage and to develop information on feasible
control measures which could be employed by the Bunker Hill Company to
control discharges to waters of the United States.
The U.S. Bureau of Mines and the Bunker Hill Company had announced
a joint research grant to the University of Idaho to study seepage from
the pond and control measures which could be applied within the pond
area (internal control). Accordingly, it was decided that the NEIC
investigation would address itself to leakage beyond the pond margin and
would utilize, wherever practicable, information developed by the Univer-
sity of Idaho study on internal control measures.
NEIC personnel conducted a reconnaissance inspection of the Bunker
Hill complex on October 16 and 17, 1975 [Appendix A]. A meeting was
held on November 10, 1975 between the NEIC geologist in charge of the
study and personnel from the University of Idaho to discuss the mutual
studies and areas of overlap.
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Permission was requested by EPA from Bunker Hill Company to enter
its property around the tailings pond for the purpose of constructing
the necessary observation wells. This permission was denied by Bunker
Hill Company. The United States then filed a motion in U.S. District
Court for an Order Compelling Discovery; Court-ordered entry was granted
on July 16, 1976.
Arrangements were made with personnel from the Federal Highways
Administration to provide a drill rig and crew. The rig and crew arrived
on August 10, 1976 and concluded drilling observation wells on August
16, 1976. After construction, the wells were completed by surging and
pumping. Geohydrologic data and ground-water samples were collected
monthly during September, October, November, and December 1976.
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II. SUMMARY AND CONCLUSIONS
1. The Bunker Hill Central Impoundment Area, gypsum pond, and slag
pile receives solid and liquid waste from the Bunker Hill mine,
mill, and smelter complex. The waste disposal system was not
designed as such and does not represent the state of the art.
Rather, the system gradually evolved over a period of years with no
overall plan and no safety or geohydrologic analysis.
2. Leakage from the waste-disposal system results from improper past
construction techniques that allow discharges of pollutants into
the South Fork Coeur d'Alene River. Bunker Hill personnel recognized
the existence and cause of the problem and the feasibility of
control 10 years ago.
3. Seepage from the ponds degrades the chemical quality of underlying
ground water and enters and damages the South Fork Coeur d'Alene
River through discrete, identifiable sources which are subject to
control.
4. Internal control measures are available to Bunker Hill Company to
reduce the losses from the ponds that result in discharges to the
South Fork Coeur d'Alene River.
5. External control measures are available to Bunker Hill Company to
capture and treat the seepage before it is discharged to the South
Fork Coeur d'Alene River. Similar measures have been employed by
other mining operations through the nation for many years, and are
described in open literature available to Bunker Hill Company and
its consultants. Bunker Hill personnel have recognized the feas-
ibility of such control for at least 10 years.
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6. The most economical control would probably involve use of an
existing gravel bed surrounding a sewer line as a linear seepage-
collection well. An upgradient well in a permeable gravel section
and grouting downgradient of the sewer line would assist in system
operation. Water from the well and sewer-line gravel would require
neutralization and metal removal in the existing Bunker Hill treat-
ment plant before discharge.
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III. RECOMMENDATIONS
1. Bunker Hill Company should immediately institute internal control
measures to reduce seepage losses through internal dikes in the
Central Impoundment Area and throughout the gypsum pond.
2. Bunker Hill Company should immediately begin design of external
seepage measures to capture and return contaminated seepage from
the ponds for treatment in the existing treatment plant, to prevent
discharges of pollutants into the South Fork Coeur d'Alene River.
3. The NPDES permit re-issuance for Bunker Hill Company should include
requirements for the installation and operation of external seepage
control measures. The effectiveness of the measures must be moni-
tored by Bunker Hill Company using observation wells drilled for
the NEIC investigation and augmented where necessary by additional
monitoring wells to be drilled by Bunker Hill Company.
Such additional monitoring wells should be cased and completed in a
manner similar to the EPA wells. No metal casings should be used.
Additional observation wells should be completed by Bunker Hill
Company between Bunker Creek and the gypsum pond and CIA, to ev-
aluate seepage losses that result in discharges to Bunker Creek.
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IV. SITE DESCRIPTION
Geohydrologic conditions in the vicinity of the Bunker Hill Central
Impoundment Area (CIA), gypsum pond, and slag pile at Kellogg, Shoshone
County, Idaho are a function of site geology, previous activities of man
upstream of the site, and pond construction techniques. The ground-
water movement and discharge from this facility has an impact on the
receiving stream.
GEOLOGY
The geologic and geomorphic history of the area surrounding the
Bunker Hill site is described in detail by Hobbs, et al. (1965).
The area is underlain by metamorphic quartzites and argillites of
the Precambrian Belt Series. These rocks are generally impermeable but
have been intensely deformed and fractured, resulting in the formation
of secondary permeabilities along the fractures.
Rocks underlying the Bunker Hill site were intruded by younger
dikes and cut by numerous faults, the most important of which is the
east-west trending Osborne Fault. The present course of the South Fork
Coeur d'Alene River roughly follows the trace of this fault and is
probably at least partly resultant from the presence of the Osborne
Fault. Most of the mineral deposits which have been exploited in the
Coeur d'Alene mining district are along and associated with the Osborne
Fault and its offshoots.
The present landscape in the Bunker Hill area results from the
intermittent dissection of a mature upland with periods of intermittent
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8
aggradation (filling). The last period of downcutting resulted in the
formation of a major broad bedrock valley along the present course of
the South Fork Coeur d'Alene River at an elevation of 50 to 100 meters
lower than the present stream channel.
Following the cutting of this major valley, a period of aggradation
began which has resulted in the filling of the valley with alluvium of
probable Quarternary age. This aggradation has resulted from the forma-
tion of Coeur d'Alene Lake and downstream features forming a base level.
The lower portion of the valley fill is comprised of large boulders
derived by stream action on upstream sediments. A period of relatively
quiescent conditions, resulted in the deposition of an extensive silt
and clay layer. Subsequent aggradation resulted in deposition of approx-
imately 10 meters of alluvium ranging in size up to cobbles on top of
the silt and clay layer. This has resulted in the formation of two
separate aquifers which are probably in only limited connection and
communication in the valley.
VALLEY HISTORY
The first discoveries of mineralization in the Coeur d'Alene mining
region took place in 1878, followed by the discovery of placer gold
deposits in the early 1880's (Koschmann and Bergendahl, 1968). Rich
deposits of lead and silver were subsequently located in 1885. A rail-
road which promoted the mining of large amounts of lead and silver ore
was completed into the area in 1887. Many of the mills continued in
operation until 1933, when virtually all the mills closed. Activity
began again shortly thereafter and has continued to the present.
Most of the early milling operations did not use any form of tail-
ings pile but rather discharged tailings directly to South Fork Coeur
d'Alene River and its tributaries. As a result, the stream overflowed
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its banks and deposited many thousands of tons of coarse jig tailings,
containing zinc and other heavy metal sulfides, onto the valley floor.
These deposits are easily identifiable at present by their rust-brown
oxidized appearance and frequently are 1.5 to 2 meters thick. Leaching
of those deposits results in the addition of some zinc and other heavy
metals to the river, especially during periods of precipitation or in
areas where water is ponded on the valley floor.
Bunker Hill drawing No. 1-6, dated March 31, 1918 (not reproduced
in this report) shows contours along the South Fork Coeur d'Alene River
valley in 1901 and 1918. These contours demonstrate the deposition of
approximately 1.5 meters of tailings material along the flood plain
during the intervening seventeen years. This deposition resulted, in
part, from the upstream discharge of jig tailings (course gravity-
separation system tailings), together with mine waste and other solid
waste materials.
BUNKER HILL POND CONSTRUCTION HISTORY
Bunker Hill Company was one of the early mining companies within
the Coeur d'Alene mining district to construct a tailings pond and
control the discharge of solids to the stream. No good record exists of
the construction of this pond; however, it is possible to reconstruct
the history of construction by examination of aerial photographs taken
at various times and of data from the Bunker Hill files.
1954 Conditions
It was not possible to ascertain the initial date of tailings pond
construction. On September 2, 1954, when aerial photographs GS-VEJ were
taken by the U.S. Geological Survey, there was a small quantity of slag
deposited at the present site of the slag pile. Mill wastes were dis-
charged from a central discharge point into a small tailings pond near
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10
the present east end of the Central Impoundment Area. A dike contained
the wastes along Highway 10 [Figure 1]. The west end of the pond was
formed by a dike (separating dike) which currently is under the gypsum
pond. The south margin of the pond was composed of a dike along the
present south dike location. According to information from the Bunker
Hill files (N.J. Sather, Aug. 7, 1969) these dikes were composed of
coarse tailings and stream gravel. Thus, they would be expected to be
highly permeable. There are indications on the photos of seepage
through the western dike. Wastes from the mine, lead smelter, and zinc
plant apparently were not discharged to the tailings pond, but rather
were discharged directly to the South Fork Coeur d'Alene River or its
tributaries.
9-2-54
3-112
SS-VEJ
f' Separting Dike
I. Sk.leh of Bunk.r Hill Foeiliti., at ,hown on U.S.G.S. Airphoto, S.pj.mb.r 2, I9S4
1958 Conditions
The next series of photographs examined was taken on October 25,
1958 by the Idaho Highway Department and is identified by the designation
190-1(11)48-35. This series of low altitude photographs was used in
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the design and construction of Interstate Highway 90 and clearly showed
conditions which obtained in the tailings pond at that time. A sketch
map [Figure 2] prepared from the Oct. 25, 1958 photos shows the facili-
ties as they existed on the date of photography. The previously used
tailings pond (east pond) was abandoned and was being sprinkled to
prevent wind erosion. A new pond (west pond) had been created between
the slag pile and the east pond. Dike construction involved the use of
peripheral discharge of sand material, with a decant pipe located near
the center of this pond, with decant discharge to the South Fork Coeur
d'Alene River. The west end of the pond was formed by the slag pile,
with tailings lapping onto the slag. The east end was formed by the
separating dike. Indications are that the separating dike had been
reinforced by coarse sand discharge. Effluent from the zinc plant and
lead smelter apparently were discharged directly to Silver King Creek.
1964-1968 Conditions
A 1964 Bunker Hill Company drawing* indicates that the western
tailings pond was in use on this date. It further indicates that a
wedge shaped area had been excavated from the eastern tailings pond for
use in fill in the construction of Interstate 90. The map indicates
plans for the construction of a new dike along the east end of the
easternmost pond, with mine water to be discharged to 'this pond. A
decant pipe was to be constructed draining into the South Fork Coeur
d'Alene River just upstream of the Interstate 90 bridge. The dike
separating the eastern and western ponds was still in the original 1954
location.
A 1966 Bunker Hill Company drawing** M-23-104, portrayed the pie-
shaped highway excavation in the eastern pond and indicated a
* Drawing No. W-10-13 "General Plant Mine Area Showing Proposed
Sewage, Mine Portal Water Disposal," Dec. 1, 1964.
** Drawing No. M-23-104 "Tailings Pond Area 1966 Proposed Expansion"
June 1966.
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1O-2B-58
Unused Tailings
"East Pond" Pond
-10
-11
Figure 1. Sketch Map showing Bunker Hill Pond Area October 25, 1958
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north-trending decant line from the west pond, a north-trending decant
pipe from the east pond, and two west-trending decant pipes from the
east pond into the west pond. In addition, the decant line draining
into the South Fork Coeur d'Alene River upstream of the Interstate
highway bridge was shown.
The presence of leakage from the Bunker Hill tailings pond and the
feasibility of seepage control was recognized as early as August 28,
1967 by R. F. Miller, a Bunker Hill employee. An internal Bunker Hill
report titled Water Pollution (Miller, 1967) recognized the existence of
seepage from the tailings pond under the highway and discharge into the
South Fork Coeur d'Alene River and recommended the installation of
perforated tile and gravel in a trench between the highway and the
tailings pond. Water from the tile was to be limed for metal removal.
In a Bunker Hill memorandum from N. J. Sather (August 7, 1969) to
R. L. Hafner, the problem of seepage was recognized and attributed to
the presence of the original north-south trending dike, previously
referred to as the separating dike.
The Idaho Highway Department again photographed the Bunker Hill
area on October 28, 1968. Figure 3, prepared from the photos, depicts
conditions as they existed on the date of photography. Conditions at
that time were similar to the conditions as portrayed on the 1964 and
1966 Bunker Hill drawings. A dike had been completed around the eastern
end of the east pond, expanding it eastward to its present site. The
pie-shaped wedge, previously excavated, was clearly visible. The upper
surface of the east pond was extremely dark in color, indicating either
slag spread on the surface to prevent wind erosion or oxidation of
material due to exposure. Tailings were discharged from a pipe ending
at the apex of the pie-shaped excavated area. The tailings sands flowed
and formed a beach in the wedge with water ponded at the easternmost end
of the section and adjacent to the eastern dike. The west pond was
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1O28-68
Interstate
Br
5-22-129
M ILL
Tailings Slurry Pipeline
-128
-127
Figure 3. Sketch Map Showing Bunker Hill Pond Area
October 28, 1968
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still intact, with recent evidence of raising of the dike by pushing
sand up with a crawler tractor. A decant pipe drained the western pond
directly into the South Fork Coeur d'Alene River while another decant
pipe drained the eastern pond into the River just upstream of the Inter-
state 90 bridge. The new eastern dike of the eastern pond had been
raised and reinforced by peripheral discharge of tailings material.
1970-1972 Conditions
A Bunker Hill Company drawing* indicates that a tailings distri-
bution line was to be extended along the entire north face of the tail-
ings pond, both the eastern and western portion. By this time, the mine
water was being discharged to the tailings pond at its present site.
A series of photographs** taken from rather low altitudes was ex-
posed by the consulting engineering firm of C^M-Hill Engineers on May 2,
1972. These show that the slag pile had grown to near its present size.
Gypsum slurry, from the phosphophoric acid plant was discharged from a
single pipe at a point at the west end of the tailings area, flowed in a
braided pattern to the east, overlapping the separating dike. There was
a slight surface indication of this dike; no indications were available
that the dike had been destroyed. Mill tailings, apparently of sand
size, were discharged from a tailings distribution line along the entire
north flank of the pond. A major delta of sand had built up along the
north dike at the point of the previous separating dike. The pie-shaped
area was almost completely filled while contaminated water from the
gypsum pond flowed to the extreme east end of the pond. Flow from
Sweeney Pond, the lead smelter waste pond, was discharged to Government
Creek (Silver King). Mine water was discharged into the eastern portion
* Draw-ing M-23-123, "West Mill 12-Inch ID Wood Stave Pipe Tailings
Line - North,," August 25., 1970.
** Designated M308.01, Roll 4, Photographs 7 to 13 and retained by
CHJ4-HHI in Bedding, Calif.
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of the combined pond. Decant from the pond was through the previously
installed pipeline which discharged into the South Fork Coeur d'Alene
River a short distance upstream of the Interstate 90 bridge.
Discharge of seepage into South Fork Coeur d'Alene River is evident
on the 1972 photographs, especially north of and slightly downstream of
the site where the old separating dike intersected the northern dike of
the present combined pond. Apparently, the dike and the delta of sand
discharged at the intersection served as a sand drain for water which
entered the subsurface, moved north and entered the South Fork Coeur
d'Alene River.
Topographic conditions in and adjacent to the Bunker Hill tailings
pond are shown on a topographic map dated July 1974 prepared for Bunker
Hill Company by the consulting firm of Limbaugh Engineers Incorporated,
Albuquerque, New Mexico, using photogrammetric methods. By the time the
photos used in preparation of this map were taken in June 1974, a dike
had been constructed separating the gypsum pond (west) and the tailings
pond (east). This dike was 400 to 600 feet east of the previous separa-
ting dike. The previous dike site was completely inundated by water
from the gypsum pond. At the time of photography, June 15, 1974, the
gypsum pond was at an elevation of 2,308.7 feet. A beach was present
around the eastern and part of the northern end of the tailings pond.
Water was in direct contact with the north dike of the tailings pond
(CIA) at the northwest corner and at the northeast corner of the gypsum
pond.
1975 Conditions
The Idaho Highway Department again flew and photographed the Bunker
Hill area on September 8, 1975. The photographs clearly documented
conditions as present on the date of photography. Mine water was
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discharged into the tailings (east) pond. Gypsum slurry was discharged
at the west end of the gypsum pond and flowed to the east. Clear water
in the gypsum pond occupied approximately the eastern half of the pond,
covering the site of the old separating dike. A beach of tailings
slimes had been built up along the eastern and northern sides of the
tailings pond (CIA). Decant from the pond was routed to the recently
constructed neutralization plant, with discharge from the plant into
Bunker Creek. Waste was discharged from Sweeney Pond into Government
Creek. Discharge of ground water into the South Fork Coeur d'Alene
River was evident, especially north of the intersection of the old
separating dike with the northern dike of the gypsum pond. This dis-
charge caused a chemical precipitate to form on the bottom of the South
Fork Coeur d'Alene River and discolored the river for approximately one-
half the width of the stream. The discharge appeared to be concentrated
in the area just downstream of a point north of the previously mentioned
dike intersection.
It was obvious from investigation of the various aerial photographs
and the Bunker Hill files that the Bunker Hill tailings and gypsum ponds
were not the result of a true design. Rather, they "just happened."
There has been no adequate engineering safety analysis of the structural
integrity of the facilities and there has been no overall plan for waste
disposal or consideration of the effect of the pond on the geohydrologic
conditions of the area. This approach is directly counter to all pub-
lished recommendations on the design, construction and operation of a
tailings pond. The Bunker Hill facility is not an engineered tailings
disposal system and does not reflect the state of the art.
EFFECT ON RECEIVING WATER
The fact that the Bunker Hill CIA and gypsum pond leaks and dis-
charges into the South Fork Coeur d'Alene River is readily apparent
through visible observation of the1 stream. The South Fork Coeur d'Alene
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18
is clear upstream of the tailings pond. When the acid discharge, which
is visible during low stream flow, enters the stream, which is at a
higher pH, various metal hydroxides (most notably ferric hydroxide)
precipitate on the bed and banks of the stream. This results in a
severe brown to yellowish-brown to white discoloration downstream from
the point of discharge seepage inflow.
In addition to the aesthetic effects, the presence and effects of
the discharge have been documented by a number of studies performed by
EPA Region X personnel. The metals loading due to seepage has been
calculated on the basis of metals loading in the stream upstream of and
downstream from the seepage inflow. Region X personnel (Ray Peterson,
personal communication) calculated that a daily seepage load addition of
1,950 Ib zinc, 0.5 Ib cadmium, 15 Ib lead, and 944 Ib fluoride occurred
during October 1975.
A similar study was performed during October 1976, when the daily
load addition due to tailings pond seepage was calculated to have in-
creased to 3,950 Ib zinc, 3.4 Ib cadmium, 15 Ib lead, and 1,000 Ib
fluoride. It was noted that the Bunker Hill tailings pond surface
elevation had been raised in an effort to prevent wind erosion of pre-
viously deposited tailings solids.
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V. RESULTS OF INVESTIGATION
Upon receipt of a court order permitting access to Bunker Hill
property, twenty-six observation holes were drilled and completed adja-
cent to the tailings pond to provide information on the quality and
direction of ground-water flow. The drilling was done with an 8-inch
continuous-flight, hollow-stem auger owned and operated by the Federal
Highway Administration. An NEIC geologist, present continuously during
the time of drilling, prepared geologic logs of the various holes.
After each hole was drilled, it was cased with 1-1/2 inch inside diam-
eter Schedule 80 PVC slotted pipe with a solid plug on the bottom.
Backfill was by slumpage of the hole as the auger was retrieved. The
holes were capped with a steel cap equipped with a lock. After drilling
was completed, the holes were surged and pumped with a centrifugal pump
to establish a clean sand filter pack. Water-table elevations were
determined and ground-water samples were collected from the wells each
month, September through December. Prior to sampling, each well was
pumped to purge water from the surrounding voids. The water from the
wells was filtered in the field through 0.45 micron filters and pre-
served. Chain-of-custody procedures were maintained on the samples in
accordance with published NEIC procedures [Appendix B]. Samples were
split with Bunker Hill personnel.
Available geologic information indicated that the South Fork Coeur
d'Alene River valley floor was underlain at a depth of approximately 10
meters by a thick clay and silt layer. With some exceptions, the holes
were drilled into this layer. Completion information on each hole is
contained in the drilling logs [Appendix C].
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STRATIGRAPHY
Findings within the area bore out previously reported geologic
conditions, that is, a clay layer at a depth of approximately 5 to 10
meters overlain by poorly sorted alluvium. The clay layer tended, to be
more silty upstream and downstream from the tailings pond. In the
tailings pond area, the layer was a tan plastic clay. Near the middle
portion of the tailings pond, there was an uplift force acting on the
clay, resulting in upward flowage of material into the hole as the auger
plug was retrieved. This is indicative of a discharge area in the
ground-water flow system. In some cases, difficulty was encountered in
emplacing the total length of casing. The final completion is shown on
the logs.
Most of the alluvium was a poorly sorted, silty, clayey sand con-
taining gravel to cobble material. However, in some of the holes, clean
sections of sand and gravel (an old gravel bar) were encountered. This
was especially true in the middle portion of the tailings pond, holes 9
to 13 [Figure 4]. Later pumpage of some of these holes indicated that
the holes were completed in an extremely clean, permeable section of
alluvium. It was observed that this section of clean alluvium was
immediately adjacent to the site of the previous north-south dike sepa-
rating the two portions of the Bunker tailings pond. The northern
extension of this clean channel of alluvium is the site of the. major
observed seepage into South Fork Coeur d'Alene River. The upstream
portion of the channel is under the gypsum and tailings ponds. Thus,
this channel serves as a conduit of ground-water flow between the pond
and the river.
GROUND-WATER MOVEMENT AND CONTAMINATION
Before establishment of the Bunker Hill Central Impoundment Area
and gypsum pond, ground and surface water in the area was at an equilib-
rium condition, with ground water generally discharging into the surface
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LEGEND
9 OISCRVATION WILL LOCATION AND NUMMI
DIIICTION Of O«OUNO-
CENTDAl IMPOUNDMENT AKEA
VATI* MOVEMENT, PALI I97«
Figure 4- location of Bunker Hill Area Obtervalion Wellt and Direction of GroundWater Movement
ro
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streams. The activities of Bunker Hill Company have modified this
equilibrium resulting in changes in ground-water movement and quality.
During the course of the study, measurements were made of ground
water elevations in the various observation wells around the Bunker Hill
pond [Table 1]. By plotting these elevations and preparing ground-water
contour maps, it is possible to deduce the direction of ground-water
movement. The following discussion is based on such information.
Pumpage of ground water by Bunker Hill Company from deep alluvium
aquifers in the Bunker Hill water-supply wells south and east of the
Central Impoundment Area has reduced the water level in the deep aquifer
with subsequent leakage from the shallow aquifer through the confining
clay layer. As a result, upstream of the Central Impoundment Area in
the vicinity of the Junior High School grounds, water moves from the
stream to the south, as shown by the arrows on Figure 4. Much of this
leakage may be around the casing of the supply wells or through old,
unplugged wells as well as through fracturing induced by seismic acti-
vity.
Seepage from the Central Impoundment Area and the gypsum pond has
created a mound on the ground-water surface, resulting in the discharge
of ground water into the South Fork Coeur d'Alene River and probably
into Bunker Creek. The flow into the South Fork Coeur d'Alene River is
along the entire north dike of the Central Impoundment Area and the
gypsum pond, as well as from the slag pile. The flow is in a saturated
zone extending upward from the underlying clay layer to the water table,
a thickness of 4 to 7 meters. Ground-water direction of movement is
generally at a bearing of approximately 300°, or a 30° angle to the
Interstate Highway.
The direction of ground-water movement is locally affected by
differences in alluvium permeability- This is most pronounced in the
area of an old buried gravel bar, observed near observation well 9.
-------
Table 1
GROUND-WATER DEPTH AND ELEVATIONS
BUNKER HILL OBSERVATION WELLS
1976
Hole No
or Site
01
02
03
04
05
06
07
08
09
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
TB#7
Lumber
Well
Casing Top
Elevation
2,229.1
2,249.8
2,248.2
2,251.6
2,249.8
2,251.4
2,250.6
2,251.0
2,254.1
2,254.2
2,254.6
2,256.4
2,255.6
2,259.4
2,256.5
2,255.0
2,256.0
2,256.6
2,260.0
2,262.3
2,271.9
2,277.3
2,282.2
2,286.5
2,276.5
2,241.6
2,240.8
Yard
2,240.2
Aug.
Depth
16.92
12.48
10.78
12.27
8.67
9.67
9.31
8.44
10.54
10.33
9.92
11.58
10.17
11.25
10.42
8.77
8.46
7.78
7.38
7.50
14.06
17.42
21.67
24.42
9.52
9.44
-
13.09
17-18
Elev.
ft
2,212.2
2,237.3
2,237.4
2,239.3
2,241.1
2,241.7
2,241.3
2,242.6
2,243.6
2,243.9
2,244.7
2,244.8
2,245.4
2,248.2
2,246.1
2,246.2
2,247.5
2,248.8
2,252.6
2,254.8
2,257.8
2,259.9
2,260.5
2,262.1
2,267.0
2,232.2
-
2,227.1
Sept
Depth
17.42
12.19
9.43
12.19
8.92
4.93
9.46
8.50
10.74
9.72
9.91
11.71
10.36
11.60
10.60
8.96
8.60
7.84
7.60
7.74
14.24
-
-
-
11.23
8.94
-
13.49
. 7-9
Elev.
ft
2,211.7
2,237.6
2,238.8
2,239.4
2,240.9
2,246.5
2,241.1
2,242.5
2,243.4
2,244.5
2,244.7
2,244.7
2,245.2
2,247.8
2,245.9
2,246.0
2,247.4
2,248.8
2,252.4
2,254.6
2,257.7
-
-
-
2,265.3
2,232.7
-
2,226.7
Sept
Depth
ft
12.10
10.36
12.19
9.00
4.63
9.36
8.33
10.71
9.7
10.00
11.70
10.34
10.34
10.54
8.90
8.58
7.90
-
7.70
-
-
-
-
-
10.28
-
-
. 10
Elev.
2,237.7
2,237.8
2,239.4
2,240.8
2,246.8
2,241.2
2,242.7
2,243.4
2,244.5
2,244.6
2,244.7
2,245.3
2,249.1
2,246.0
2,246.1
2,247.4
2,248.7
-
2,254.6
-
-
-
-
-
2,231.3
-
-
Oct.
Depth
ft
17.73
12.75
11.25
12.60
9.17
6.08
9.60
8.78
10.72
9.81
10.00
11.77
10.40
10.70
10.58
8.95
8.57
7.80
7.43
7.45
14.01
19.60
Silted
30.30
11.95
9.76
13.10
13.42
5-6
Elev.
2,211.4
2,237.1
2,237.0
2,239.0
2,240.6
2,245.3
2,241.0
2,242.2
2,243.3
2,244.4
2,244.6
2,244.6
2,245.2
2,248.7
2,245.9
2,246.0
2,247.4
2,248.8
2,252.6
2,254.9
2,257.9
2,257.7
Nov
Depth
.
13.54
11.83
12.84
9.31
9.55
9.85
8.91
10.95
10.61
10.30
12.00
10.75
9.95
10.87
9.31
9.00
8.28
8.13
8.25
15.18
22.95
. 10-11
Elev.
ft
.
2,236.3
2,236.4
2,238.8
2,240.5
2,241.8
2,240.8
2,242.1
2,243.1
2,243.6
2,244.3
2,244.4
2,244.8
2,249.4
2,245.6
2,245.7
2,247.0
2,248.3
2,251.9
2,254.1
2,256.7
2,254.3
Dec
Depth
18.28
11.82
10.03
12.33
9.18
9.90
9.62
8.78
10.92
10.48
10.20
11.96
10.28
9.52
10.80
9.15
8.78
8.05
8.00
8.15
15.00
23.58
. 8-9
Elev.
ft
2,210.8
2,238.0
2,238.2
2,239.3
2,240.6
2,241.5
2,241.0
2,242.2
2,243.2
2,243.7
2,244.4
2,244.0
2,245.3
2,249.9
2,245.7
2,245.8
2,247.2
2,248.6
2,252.0
2,254.1
2,256.9
2,253.7
Silted
2,256.2
2,264.5
2,231.8
2,227.7
2,226.8
-
14.98
10.65
13.43
13.76
-
2,261.5
2,231.0
2,227.4
2,226.4
29.38
15.62
9.73
13.15
13.38
2,257.1
2,260.9
2,231.9
2,227.6
2,226.8
co
-------
24
This area of increased permeability serves as a ground-water drain,
lowering the water table and hence functioning as a sink for ground-
water movement from the south and east. This modifies the direction of
ground-water flow as shown on Figure 4. It further serves to drain
ground water recharged from seepage through the buried separating dike
which is located to the south, under the existing gypsum pond. The fact
of this movement is shown not only by ground-water contours but by
evidences of ground-water contamination.
High concentrations of fluoride are not indigenous to ground or
surface waters in the South Fork Coeur d'Alene River Valley. Large
amounts of fluoride are imported to the area in the phosphate rock which
serves as a raw material in the fertilizer plant. A large percentage of
this fluoride is discharged to the gypsum pond along with the gypsum
slurry. A sample of water collected on December 9, 1976 from the clari-
fied water at the northeast corner of the gypsum pond was found to
contain 840 mg/1 fluoride. Fluoride is mobile and not easily precipi-
tated in an acid media; therefore, it serves as an excellent tracer of
Bunker Hill ground-water contamination.
Gypsum from the phosphate plant previously overflowed the entire
area of the Bunker Hill gypsum pond and Central Impoundment Area before
the existing dike was constructed between the two ponds. Hence, gypsum
underlies the Central Impoundment Area sediments and could reasonably be
expected to be present in the seepage from both ponds.
Fluoride has been found to be beneficial when present in small
quantities in potable drinking water supplies. High concentrations of
fluoride are detrimental, damaging the teeth of those drinking the
water. The maximum concentration of fluoride permitted in the water
supply is a function of temperature, decreasing with increasing tempera-
ture. Concentrations over approximately 2.5 mg/1 are not acceptable at
any temperature. Fluoride can be removed to concentrations of approxi-
mately 15 mg/1 by lime addition.
-------
25
As shown in Figure 5, the background ground water has approximately
0.2 mg/1 of fluoride. This is greatly modified as a result of seepage
from the Bunker Hill ponds. All the ground water to the north and
northwest of the ponds exhibited abnormally high fluoride levels, ranging
up to 170 mg/1 in one sample collected from observation well 9. As
shown in Table 2, the highest values are present in wells 9 and 10, in
the old buried gravel channel. This tongue of high concentrations of
fluoride probably connects with the old separating dike between the two
original tailings ponds. The data indicates there is a direct hydro!ogic
connection from the gypsum pond through the separating dike, through the
old gravel bar, and directly into the South Fork Coeur d'Alene River.
Zinc is present in high concentrations in the Bunker Hill ore,
mostly in the form of zinc sulfide which readily oxidizes to yield
dissolved zinc in a sulfuric acid solution. During the early days of
milling operations in the South Fork Coeur d'Alene Valley, zinc was not
recovered; hence, the jig tailings within the area tend to be extremely
high in zinc sulfide. Even today, zinc recovery is not complete, with
the result that zinc sulfide is present in tailings discharged to the
Bunker Hill tailings pond. Zinc is present in liquid waste discharged to
the CIA from the zinc plant.
Zinc is highly toxic to aquatic organisms at low concentrations.
The toxic concentration is a function of water hardness but generally is
less than 1 mg/1. It can be removed by the addition of lime to form
zinc hydroxide. Further zinc removal can be achieved by the addition of
inorganic sulfide ions to form zinc sulfides.
Zinc is relatively mobile as a heavy metal in ground water, espe-
cially in acid conditions. It will adsorb to some extent on the rocks
forming an aquifer, and is one of the last heavy metals to be removed
by pH adjustment.
-------
Flgurt 5. Mean fluorldf Conttntrallont In Bunker Hill Obicrvol/on W*ll>, S«pl-D«c, 1974
t\J
CT>
-------
27
Table 2
RESULTS OF FLUORIDE ANALYSES
BUNKER HILL OBSERVATION WELL SAMPLES
1976
Observation
Well No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Sept. 10
mg/1
1.4
1.5
8.8
11
-
2.2
11
29
29
12
10
11
_
9
10
9.3
6.5
-
10
-
-
-
-
-
1.6
Oct. 5-6
mg/1
3.6
4.0
22
34
-
30
31
170
120
41
25
23
_
17
13
21
15
22
32
12
0.3
-
-
0.3
30
Nov. 10-11
mg/1
2.7
1.4
10
17
_
6.0
15
78
92
16
13
15
13
12
8.2
8.3
4.9
8.9
10
0.5
0.2
-
-
0.1
0.8
Dec. 8-9
mg/1
2.1
2.0
15
21
-
6.1
20
94
102
22
17
18
-
14
15
14
9.6
16
20
0.7
-
-
-
0.3
1.9
Mean/Std.Dev.
2.4/0.9
2.2/1.2
14/6
21/10
-
11/13
19/9
93/58
86/40
23/13
16/6
17/5
13/3
12/3
13/6
9/4
16/7
18/10
4/7
-
-
-
0.2/0.1
8.6/14.3
- No sample
-------
28
Analyses of samples collected from the various observation wells
[Table 3] indicate that zinc is present in relatively high concentrations
in the ground water in the shallow alluvium of the South Fork Coeur
d'Alene Valley due to leaching from jig tailings which cover the floor
of the South Fork Valley. Despite the relatively high values (approxi-
mately 1 mg/1) which comprise background levels, the effect of the
Bunker Hill tailings pond leakage was clearly demonstrated in the abnorm-
ally high concentrations of zinc in the observation wells. As shown in
Table 3, values of zinc as high as 180 mg/1 were observed in observation
wells along the north side of the dike. By way of comparison, a sample
collected December 9 from the clear water in the western end of the
Bunker Hill CIA was found to contain 220 mg/1 zinc. The highest average
values of zinc in the observation wells were present in wells 11, 13,
and 15, along the eastern side of the old gravel bar [Figure 6]. This
probably reflects a conduit effect from the separating dike and from
within the Central Impoundment Area moving into this channel. Zinc is
probably also present in seepage from the gypsum pond as a result of
leaching of zinc from old tailings which underlie the gypsum pond.
Cadmium behaves similarly to zinc but is somewhat less mobile. The
only wells which exhibited high cadmium values were in wells 2 and 3,
adjacent to the east end of the slag pile and the point of discharge of
gypsum and in wells 9 and 10 in the old gravel bar [Table 4]. The high
values in wells 2 and 3 probably reflect acid leaching of slag as acid
water moves from the point of gypsum discharge downward through the slag
and thence into the ground water. Wells 9 and 10 represent the relatively
rapid movement of ground water through the permeable gravel bar with
little chance for metal adsorption.
Lead does not generally tend to be mobile in a ground-water environ-
ment. The only wells containing significant quantities of lead were
wells 2 and 3, adjacent to the slag pile and the point of gypsum dis-
charge, and wells 9 and 10 in the old gravel bar section [Table 5]. The
explanation for the presence of lead in these wells is similar to that
for cadmium.
-------
29
Table Z
RESULTS OF ZINC ANALYSES '
BUNKER HILL OBSERVATION WELL SAMPLES
1976
Observation
Well No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Sept. 10
mg/1
16
44
101
118
-
83
81
100
115
160
83
103
-
180
86
130
104
-
55
-
-
-
_
M
16
Oct. 5-6
mg/1
.
19
23
105
150
-
130
170
150
150
170
150
150
-
150
150
150
140
77
70
29
19
-
-
1.0
8.2
Nov. 10-11
mg/1
61
36
no
120
-
96
120
110
110
140
120
120
120
no
120
120
90
78
65
5.5
20
-
_
0.9
7.0
Dec. 8-9
mg/1
.
50
54
120
120
-
92
130
no
no
130
120
120
-
no
no
12
85
79
70
13
-
-
_
0.8
5.7
Mean/Std.Dev.
.
36/22
39/13
109/8
127/15
-
100/21
125/37
118/22
121/19
150/18
118/27
123/20
-
138/34
116/26
103/62
105/25
78/1
65/7
16/12
20
-
..
019/0.1
9.0/4.6
- No sample
-------
LEGEND
OISEIIVATION WILLS
»' MIAN ZINC CONCINTHATIONS. mg/l
) %
\ ZINC CONCENtlATION CONIOUI
Figure 6. M«on Zfnc Conc»ntroflonf fn Bunlc*r Hifl Obivrvofion Wvffi, 5«pf D»e, 1976
co
o
-------
31
Table 4
RESULTS OF CADMIUM ANALYSES
BUNKER HILL OBSERVATION WELL SAMPLES
1976
Observation
Well No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Sept. 10
mg/1
0.07
0.14
0.03
0.02
-
0.04
*
0.25
0.39
*
*
*
_
0.03
0.02
0.04
*
-
*
_
-
-
-
_
*
Oct. 5-6
mg/1
0.07
0.08
*
*
-
0.02
0.02
0.35
0.38
*
0.02
*
-
*
0.02
0.04
0.04
0.02
*
*
0.07
-
_
*
*
Nov. 10-11
mg/1
0.15
0.16
*
*
-
*
*
0.37
0.52
*
*
*
1.8
*
*
*
*
*
*
*
0.13
-
_
*
*
Dec. 8-9 Mean/Std.Dev.
mg/1
0.27 0.14/0.09
0.37 0.19/0.13
*
*
_
*
*
0.35 0.33/0.05
0.43 0.43/0.06
*
*
*
_
*
*
*
*
*
*
0.15
-
_
_
*
*
- No sample
* Less than MQDC
-------
32
Table 5
RESULTS OF LEAD ANALYSES
BUNKER HILL OBSERVATION WELL SAMPLES
1976
Observation
Well No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Sept. 10
mg/1
0.17
0.21
*
*
_
*
*
0.04
0.04
*
*
*
-
*
*
0.04
*
-
*
-
-
-
-
-
*
Oct. 5-6
mg/1
0.5
1.0
0.3
*
_
*
*
0.8
0.4
*
*
*
-
*
*
0.3
*
*
*
*
*
-
-
*
*
Nov. 10-11
mg/1
0.9
1.1
*
*
_
*
*
*
0.4
*
*
*
2.9
*
*
*
*
*
*
*
*
-
-
*
*
Dec. 8-9 Mean/Std.Dev.
mg/1
1.3 0.7/0.5
1.8 1.0/0.6
*
*
_
*
*
*
*
*
*
*
-
*
*
*
*
*
*
*
-
-
-
*
*
- No sample
* Less than MQDC
-------
33
Iron and manganese tend to be associated with the tailings solids
discharged by Bunker Hill Company and are easily mobilized following
sulfide oxidation. While iron is removed at a relatively low pH, mangan-
ese is the last common heavy metal to be removed. Hence, a comparison
in the behavior between the two indicates the ground-water response as a
result of seepage from the ponds.
Wells which constitute background sampling stations (wells 22 and
25) generally contained no detectable iron [Table 6] and only low levels
of manganese [Table 7]. All of the wells to the north and northwest of
the Bunker Hill ponds contained abnormally high concentrations of both
metals, indicative of contamination by acid seepage from the two Bunker
ponds. These metals are responsible for much of the visual degradation
in the South Fork Coeur d'Alene River where the acid seepage enters the
stream and forms brown metal hydroxide precipitates on the rocks which
comprise the bed and banks of the stream. Again, the highest values of
iron and manganese tended to be in and adjacent to the old stream channel,
which serves as a main conduit for discharge from the Bunker ponds into
the South Fork Coeur d'Alene River.
A pond of seepage water has collected along the north toe of the
gypsum pond dike. A pipe was observed to have been installed between
the pond and a nearby highway drain, with flow from the highway drain
into the South Fork Coeur d'Alene River. During the monthly visits
August through December 1976, this pipe was observed to be continuously
discharging into the highway drain. A sample of this water, collected
from the discharge end of the 4-inch PVC pipe on September 10, 1976 was
found to contain 2.6 mg/1 fluoride, 0.02 mg/1 cadmium, 2.2 mg/1 iron, 21
mg/1 manganese, 0.04 mg/1 lead, and 4.7 mg/1 zinc. The water and its
pollutants reach the South Fork Coeur d'Alene River. This discharge is
not authorized by the existing NPDES permit.
-------
34
Table 6
RESULTS OF IRON ANALYSES
BUNKER HILL OBSERVATION WELL SAMPLES
1976
Observation
Well No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Sept. 10
mg/1
16
25
140
210
-
9.2
140
270
270
130
160
160
-
140
170
170
110
-
50
-
_
-
-
-
17
Oct. 5-6
mg/1
26
16
150
180
-
100
170
290
310
180
190
180
-
170
190
180
150
95
80
7.1
*
-
-
*
9.4
Nov. 10-11
mg/1
81
19
140
180
-
73
160
310
320
180
190
190
*
150
190
170
130
130
89
*
*
-
-
*
11
Dec. 8-9
mg/1
40
2.6
140
180
-
40
170
330
320
180
190
190
-
150
160
150
120
130
88
*
_
-
-
*
9.5
Mean/Std.Dev.
41/29
16/9
142/5
188/15
-
56/39
160/14
300/26
305/24
168/25
182/15
180/14
152/13
178/15
168/13
128/17
118/20
77/18
12/4
- No Sample
* Less than MQDC
-------
35
Table 7
RESULTS OF MANGANESE ANALYSES
BUNKER HILL OBSERVATION WELL SAMPLES
1976
Observation
Well No.
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
Sept. 10
mg/1
50
28
72
69
-
102
57
58
68
54
63
57
-
60
63
75
62
-
41
-
-
-
-
-
14
Oct. 5-6
mg/1
32
16
62
56
-
79
56
59
63
54
60
54
-
57
58
60
66
48
40
220
1.5
-
-
1.1
6.4
Nov. 10-11
mg/1
49
23
64
57
_
88
56
61
66
53
57
56
87
52
61
56
56
50
52
9.2
3.7
-
-
0.7
8.1
Dec. 8-9
mg/1
54
44
56
54
_
87
55
60
61
50
57
56
-
52
54
52
53
46
52
85
-
-
-
0.9
6.6
Mean/Std.Dev.
46/9
28/12
64/7
59/7
_
89/10
56/1
60/1
64/3
53/2
59/3
56/1
55/4
59/4
61/10
59/6
48/2
46/7
105/107
0.9/0.2
8.8/3.6
- No Sample
* Less than MQDC
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36
Much of the previous discussion on contaminant movement has revolved
around the function of the old gravel bar adjacent to wells 9, 10, 11,
12, and 13 as a ground-water drain. This gravel bar serves to collect
ground water moving from the south and east and discharge it directly
into the South Fork Coeur d'Alene River. Apparently, the old gravel bar
is in almost direct ground-water connection with the old separating
dike. This dike was constructed of river gravel and jig tailings and
serves as a drain under much of the gypsum pond. Thus, the dike and old
gravel bar serve the purpose of a French drain, or ground-water conduit,
for seepage from much of the Bunker Hill pond to discharge into the
South Fork Coeur d'Alene River by a confined and discrete conveyance,
which could be easily controlled and collected.
As shown in Figures 5 and 6, the quality of ground water north and
northwest of the Bunker Hill tailings pond has been appreciably degraded
below the quality of natural ground water. The contamination involves a
zone of saturated alluvium 4 to 7 meters thick between the underlying
clay layer and the water table, along the north portion of the tailings
pond and the gypsum pond, a distance of approximately 1.5 km. When
viewed on the regional scale of the South Fork Coeur d'Alene River
valley alluvium, this is an extremely small portion of the total volume.
It comprises a rectangular prism 4 to 7 meters thick by 1.5 km long.
This constitutes a discernible, confined, and discrete conveyance of
contaminated seepage from the Bunker Hill ponds discharging to the South
Fork Coeur d'Alene River. Techniques are available to capture and
control such seepage.
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VI. TAILINGS DAM TECHNOLOGY
In the early mining days, tailings, or waste solid material from
milling operations, were something to be disposed of as inexpensively as
possible, usually by direct discharge into nearby streams. Later
operations began to use tailings dams, constructed as inexpensively as
possible by self-constructing techniques. The use of tailings dams
resulted from two factors: downstream effects on the receiving water,
and the hope that future technology would permit recovery of additional
values from the tailings.
The first significant literature on tailings dam construction
techniques was a series of eight articles by Walter B. Lenhart (1949,
1950, 1951), which appeared in the journal "Rock Products." In this
series, the dam construction methods used at various Arizona copper
mills were described. Copies of these articles were found to be a part
of the Bunker Hill Environmental Department files during discovery
proceedings March 18-19, 1976.
After the "Rock Products" articles, several other journal articles
appeared describing improved techniques. Some of the first and most
significant quantitative investigations of tailings dam construction and
the effects of the dams on ground water were done by the University of
Idaho and the Spokane Mining Research Laboratory, U.S. Bureau of Mines.
Much of this work was done under the supervision of, or in conjunction
with, Dr. Roy Williams, a frequent consultant to the Bunker Hill Company
Continuing interest in the field of tailings disposal was indicated
by a four-day International Tailings Symposium in Tucson, Arizona in the
latter part of 1972 under the direction of the Journal "World Mining."
Proceedings of this symposium were published under the title "Tailings
Disposal Today" (Aplin and Argall, 1973). A total of thirty-four papers
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38
described tailings disposal techniques. The Bunker Hill Company, in
response to government interrogatories, stated this to be the authori-
tative work on tailings disposal technology.
Two papers from the book "Tailings Disposal Today" are of special
interest. In the first, C. 0. Brawner and D. B. Campbell (1973) of the
consulting firm of Golder, Brawner and Assoc., Ltd., address "The Tailings
Structure and its Characteristics -- A Soils Engineer's Viewpoint."
This firm has done work on tailings disposal throughout the world. In
speaking of seepage control, the authors state "if the seepage water
contains contaminant constituents, the volume of seepage must be determined
to evaluate the influence on adjacent land and water sources. If potential
contamination is above allowable limits, the design must incorporate
procedures to prevent leakage, to maintain it within tolerable limits,
or to remove the contaminants." They continue, "if the seepage through
a foundation or abutments exceeds the amount allowable, it must be
reduced or if deleterious substances such as radioactive materials or
poisonous chemicals are involved, total control of seepage is necessary.
With the present knowledge and experience available in soil mechanics,
this is feasible."
In another paper, James R. Swaisgood and George C. Tolland (1973),
of the firm of Dames and Moore, address "The Control of Water in Tailings
Structures." In this paper, the authors describe seepage-control techniques
which can be applied to existing tailings dams. These include the use
of drainage wells to intercept seepage flow or the use of an interception
trench, coupled with the construction of a dike of impermeable material
downgradient from the tailings pond. The authors state "drainage wells
can also be used to aid in controlling seepage outflow. This system has
been successfully used by Cities Service Company to control seepage in a
tailings embankment in Miami, Arizona."
s
As can be seen by the foregoing, technology does exist for tailings
dam construction and seepage control and is available to the mining
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39
industry in the form of consultants, literature and experience on the
part of mining personnel. As will be discussed, such technology has
been applied at a number of mining operations throughout the nation.
The volume of seepage leaving a tailings pond or flowing through
permeable media is directly proportional to the permeability of the
material through which the seepage is flowing, the cross-sectional area
of permeable media and the gradient, or slope, of the water table.
Reductions in seepage flow can be accomplished by reducing any of these
variables.
Measures can be taken within a tailings pond to reduce the total
amount of seepage from the pond by varying the permeability or the
hydraulic gradient. Bunker Hill Company has attempted a small amount of
this type of control by the construction of slime beaches, or beaches
composed of material less than 200-mesh grain size, around the internal
margin of the dikes. This has the dual effect of reducing the permeability
of the bottom material of the tailings pond and increasing the horizontal
distance between the free water surface and the point of potential
discharge, thereby reducing the hydraulic gradient serving to drive the
ground water to the potential discharge point. These measures have not
been taken along the dike between the tailings pond and the gypsum pond,
within the gypsum pond area, or along internal dikes in the CIA.
The gypsum crystal slurry filling the gypsum pond has a very high
permeability and can be expected to recharge water to the subsurface
unless measures are taken to reduce the permeability. The rate of
seepage could be reduced by the discharge of slime beaches around internal
dikes within the tailings pond, and around the interior face of the
gypsum pond dike. If problems would result from mixing of the liquid
within the gypsum pond with liquid from the tailings pond, it would be
possible to utilize the addition of drilling mud or other clay material.
It should be noted that the gypsum beach, which laps onto the
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40
lower portion of the slag pile, has an almost infinite permeability,
with the result that much of the water moves vertically down through the
gypsum beach before entering the free-water pond. A layer of slimes or
drilling mud built up on the gypsum beach would greatly reduce this
seepage loss.
Many mining operations and solar evaporation operations have used
liners to reduce seepage. Such liners are extremely expensive but can
be used to greatly reduce the amount of seepage leaving a pond. In
general, such installations are not recommended in existing ponds due to
possible structural problems. However, significant reduction in the
leakage from the gypsum pond could be realized by a partial lining of
the gypsum beach, coupled with external control measures.
Internal control measures can be very effective in reducing the
permeability of a tailings pond bottom and sides, thereby reducing the
seepage loss from the pond. However, no internal measures can be
completely effective at stopping seepage loss. Their greatest use is as
an adjunct to external control measures. In this way, the internal
measures serve to reduce pumping and treatment costs of the external
control systems. External control measures are .designed to .alter one or
'*'% , ..' i .
more of the variables controlling permeable media flow, that is, the
permeability, hydraulic gradient, and cross-sectional area.
Grouting has been used along and downstream of the toe of tailings
dams and water supply reservoirs to reduce the permeability of material
under the dam. This generally is best accomplished downgradient of the
pond to prevent problems of potential erosion (piping) and structural
failure. This has been carried to its ultimate in a number of operations
where slurry trenches or actual subsurface dams composed of plastic
sheet have been used to render the permeability as nearly zero as is
possible. Plastic sheeting, coupled with collection wells, has been
used by Allied Chemical Company at a trona mine in southwestern Wyoming.
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41
The hydraulic gradient tending to drive water toward the point of
discharge can be modified by the use of injection wells between the pond
and the discharge point, reversing or lessening the hydraulic gradient.
Such techniques are commonly employed in the prevention of sea water
intrusion into potable aquifers.
Most commonly employed seepage control measures in the mining
industry attempt to capture the seepage by wells, ditches, or other
techniques for pumping back into the pond or directly to the treatment
systems. Because of the acid nature of the ground-water seepage and the
high metals concentration present, it would be necessary to treat this
intercepted water before allowing its discharge to receiving streams.
The treatment could be achieved by discharging back to the tailings
pond, with flow through the pond into the treatment plant, or by piping
the collected seepage directly to the treatment plant. Since the seepage
would have very low suspended solids concentrations, certain advantages
could be achieved by a direct piping of the discharge to the treatment
plant. Metals recovered from the seepage could be reclaimed, offsetting
a part of the cost.
According to Bunker Hill personnel (Grosser, 1976), the existing
Bunker Hill treatment plant is now operating -at less than the hydraulic
design capacity. If, however, the treatment plant does not have sufficient
hydraulic capacity to treat this intercepted seepage, a reduction in
flow to the plant could be achieved by the installation of mine infiltration
control measures such as are recommended by Bunker Hill consultants
(Williams, 1975). These techniques would greatly reduce the amount of
acid mine drainage and metals being discharged to the tailings pond and
hence would have the effect of reducing the operating costs for the
treatment plant. The measures would further provide excess hydraulic
capacity within the treatment plant to treat the intercepted seepage.
Metals discharge from the plant is regulated by the existing Bunker Hill
NPDES permit.
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42
The aim of all of the external control measures is to capture
seepage before it enters the river but at the same time prevent the
movement of water from the river through the alluvium back to the seepage-
collection facility. To do this, it will be necessary to lower the
water table at the point of seepage interception to an elevation equal
to that of the stream directly downgradient. If the water level is
lowered more than this, it will induce flow from the river back to the
seepage collection system. If the ground-water level is not lowered to
the stream level, some of the seepage will bypass the collection facility
and discharge to the stream. Prevention of movement from the stream
back to the interception facility can be effected by a.,;number of techniques,
including grouting of the permeable media, installation of pTastic dams
in a trench, installation of slurry trenches or reinjecting treated
effluent into a line of reinjection wells. This latter system has been
chosen for a seepage collection and ground-water rehabilitation system
downgradient of the Homestake Partners uranium mill at Grants, New
Mexico. The plastic sheet technology has been utilized by Allied
Chemical Company in Green River, Wyoming. Slurry trench technology is
widely practiced in the construction industry.
Most seepage collection measures which have been installed at
existing tailings ponds involve the use of vertical collection wells,
drilled in a line parallel to and downgradient from the tailings pond
toe. In the case of the Bunker Hill situation, this would involve a
number of wells between the toe of the dike and the Interstate highway.
Because of the variability of the alluvium, it would be necessary to
vary the spacing and/or pumpage rates as a function of the aquifer
permeability. Each of the wells would be approximately 10 meters deep,
bottoming in the clay layer which underlies the site. Pumping rates and
spacing would have to be designed on the basis of more extensive sampling
and geophysical investigations. It is obvious that a large percentage
of the pumping capacity would have to be in the buried alluvial channel,
north of the old separating dike. This is in the area of observation
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43
wells 9 through 13. For purposes of preliminary cost estimation, it
was assumed that a total of 50 wells, each 10 meters deep, would be
required. Such wells could be drilled, cased, and equipped with a
suitable pump for less than $l,000/well, or a total of $50,000. A
system including liquid-level controls and piping could be installed for
less than $100,000.
Because of the low pumping lifts involved, pumping costs for the
system would not be excessive, certainly minor in terms of the present
ground water pumping by Bunker Hill.
The old Miami Copper Company operation at Miami, Arizona had a
tailings pond very similar in geohydrologic conditions to the Bunker
Hill situation. In this operation (described in the "Rock Products"
series available in the Bunker Hill files) a drift (horizontal tunnel)
was driven in the underlying clay confining layer, and churn-drill holes
were drilled into the drift from the surface to permit the vertical
drainage of seepage into the drift. Infiltration to the drift was then
pumped out and returned to the processing plant. Such a system would be
very effective in collecting the seepage; however, it would be extremely
capital intensive in this day of high labor costs.
Leakage could be collected and prevented from discharging to the
stream by constructing an open ditch to below the ground-water level,
between the Interstate and the toe of the dike. Such ditch collection
techniques are widely utilized in the phosphate industry in southern
Florida and are described in the recently released book by Dr. Roy
Williams (Williams 1975, pg. 167). In the case of the Bunker Hill
operation, this would involve an open ditch approximately 4 meters deep.
If need be, the trench could be filled with gravel, with sumps along the
ditch, to permit better control of ground-water levels to correspond to
stream levels. The gravel could serve to provide enough flow resistance
to provide an east-west slope corresponding to the stream gradient.
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44
A system very similar to the open, gravel-filled ditch is already
available to Bunker Hill Company. The main interceptor sewer for the
South Fork Coeur d'Alene Sanitation District lies between the tailings
pond and the Interstate. This ditch is constructed beneath the water
table. The sewer line is bedded in slag or in gravel between 1 and 1.5
inch diameter. During the construction of the ditch, many problems were
encountered due to ground-water infiltration. The existing ground-water
level covers the sewer pipe, with evidence that infiltration of ground
water into the sewer line is occurring. It would be relatively easy to
convert the gravel bedding of this sewer line to a gravel-filled "French
drain." All that would be required would be installation of pumps at
intermittent locations along the sewer line. It would be possible to
install a sump and pump at each manhole, with provision for pumping
ground water as required to maintain the ground-water level in the sewer
ditch at the elevation of the adjacent river. This would require lowering
the water a maximum of approximately 1.1 meters. This would prevent
movement either from or toward the river and would effectively prevent
any leakage from the Bunker Hill tailings pond from being discharged
into the South Fork Coeur d'Alene River. In the case of the clean
gravel bar encountered adjacent to the old separating dike, it may be
necessary to install one large capacity well and pump upgradient between
the sewer line and the tailings pond to capture a portion of the seepage
before it flows into the gravel, thus overwhelming the carrying capacity
of the gravel jacket surrounding the pipe.
Such a system, utilizing the existing gravel drain would, of course,
require approval by the South Fork Sanitation District and would require
i.
special easements to be granted by the Idaho Highway Department.
However, such requirements do not appear beyond the realm of possibility.
The use of the sewer-bedding gravel as an interceptor would appear
to be the least costly technique for solving the problem of the ground-
water seepage, that results in a discharge to the South Fork Coeur
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45
d'Alene River with a cost appreciably less than the use of wells. Water
pumped from the sumps would require neutralization and metals removal.
To ease the problems of maintaining water level in the sewer line trench
at the stream level, grout could be injected in the gravel section
between the sewer line and the river in the vicinity of observation well
9, and a large-capacity well could be drilled and completed in the
gravel bar upgradient of the sewer line. Water from the well and from
the sewer-line gravel sumps could be pumped into the CIA for eventual
flow to the existing treatment plant or could be piped directly to the
treatment plant, thereby eliminating the mixing of the clear ground
water with turbid pond water.
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46
REFERENCES
1. Aplin, C. L. and G. 0. Argall, Jr. (Editors) 1973, "Tailings Disposal
Today," Miller Freeman Publications, Inc., San Francisco, 861 p.
2. Brawner, C. 0. and D. B. Campbell, 1973, "The Tailing Structure and
Its Characteristics - A Soils Engineer's Viewpoint," in Tailings
Disposal Today, Miller Freeman, p. 59-96.
3. Grosser, Ralph, Oct. 7, 1976, Personal Communication.
4. Hobbs, S. W., A. B. Griggs, R. E. Wallace, and A. B. Campbell,
1965, "Geology of the Coeur d'Alene District, Shoshone Co., Idaho,"
U. S. Geological Survey Professional Paper 478, 139 p., 10 pi.
5. Koschmann, A. H. and M. H. Bergendahl, 1968, "Principal Gold-
Producing Districts of the United States," U.S. Geological Survey
Professional Paper 610, p. 139.
6. Lenhart, W. B., Dec. 1949, "Construction of Tailings Ponds," Rock
Products Vol. 52 No. 12.
7. Lenhart, W. B., 1950, "Control of Tailings from Washings Plants,"
Rock Products Vol. 53, Nos. 7, 9, 10.
8. Lenhart, W. B., 1951, "Control of Tailings from Washing Plants,"
Rock Products Vol. 54, Nos. 2, 5, 9, 10.
9. Miller, R. F., Aug. 28, 1967 "Water Pollution," Bunker Hill Company
internal report, 4 p.
10. Peterson, Ray, Jan. 13, 1977, personal communication.
11. Sather, N. J., Aug. 7, 1969 "Gypsum Disposal Pond" Bunker Hill
Company Interoffice Memorandum to R. L. Haffner.
12. Swaisgood, J. R. and G. C. Toland, 1973, "The Control of Water in
Tailings Structures," in Tailings Disposal Today, Miller Freeman,
p. 138-163.
13. Williams, R. E., 1975, "Waste Production and Disposal in Mining,
Milling, and Metallurgical Industries," Miller Freeman, San Francisco,
489 p.
-------
APPENDIX A
Reconnaissance Visit of
Bunker Hill Company
October 16 and 17, 1975
-------
RECONNAISSANCE VISIT OF
BUNKER HILL COMPANY MINE, MILL & SMELTER COMPLEX
KELLOGG, IDAHO
FACILITY ADDRESS: The Bunker Hill Company, P.O. Box 29, Kellogg, Idaho 83837
DATE OF VISIT: October 16 and 17, 1975
PARTICIPANTS:
Gene Baker, Vice President, Environmental Affairs Division,
Bunker Hill Company
Ralph Crosser, Manager of Environmental Affairs, Bunker Hill Company
Merv Aiken, Environmental Technician, Bunker Hill Company
William Boyd, Attorney, Brown, Peacock, Keane, and Boyd
Robert Borman, Superintendent, Mill Concentrator
Joe Acree, Superintendent, Phosphate Plant
Jim Rouse, EPA, NEIC ^
Robert Harp, EPA, NEIC
Ray Peterson, S&A Division, Region X, EPA
Ken Brooks, S&A Division, Region X, EPA (October 16)
Jack Sceva, S&A Division, Region X, EPA
The purpose of our visit was to conduct a facility reconnaissance and
inspection'to determine what unit operations are being conducted and what.
wastes can be expected. Based on this information, sampling and flow
measurement locations would be identified for the Second Phase Survey,
Basically; we needed to: a) define geohydrologic conditions in the vicinity
of the Central Impoundment Area (CIA); and b) to discuss and evaluate the
sources, quantities and qualities of wastewaters entering the CIA. To
better accomplish these goals, we asked Messrs. Crosser. and Baker if .process
flow and piping diagrams, waste sewer piping maps, and technical documents'
on the various operations might be obtained. Mr. Baker first indicated he
saw no difficulty in providing this type information but in view of the
legal actions being taken against the company he felt it necessary to discuss
"our request with Mr. William Boyd, who represents Bunker Hill in all legal
actions. In our subsequent meeting, Mr. Boyd showed us a copy of a letter
dated September 18, 1975 written by Mr. Paul L. Westberg, U. S. Attorney,
Boise, Idaho to Mr. Boyd regarding our visit (a copy of Mr. Westberg's letter
was not available to NEIC prior to our visit). Mr. Boyd emphasized that our
request for information, in his opinion, went beyond that indicated in Mr.
Westberg's letter. To determine if there was a misunderstanding, he called
Mr. Westberg who, from our end of the conversation, apparently agreed with
Mr. Boyd's interpretation. Mr. Boyd stated that it would be no problem .for
us to have a tour of the plants, but no flow diagrams, no details on process'-. .
operations, and no detailed technical information would be provided. This*"
Information would need to be requested in writing. Mr. Boyd indicated he
expected his clients would have to answer technical questions and provide -
technical documents at a later date but it could not be now. He stated the
Bunker Hill Company employees accompanying us through the plants could answer
general questions.
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-2-
The following is a discussion of the information received and of our
observations during the plant survey.
GENERAL
The Bunker Hill Company operates an integrated mining, milling and
smeltcring complex near Kellogg, Idaho [Figure ]]. Ore from mines owned
by the Company is mined through the Kellogg tunnel and other smaller
workings and milled in the Bunker Hill concentrator where flotation
concentrates of lead and zinc sulfide are prepared. These concentrates,
together with concentrates purchased from outside sources, are fed into
a lead smelter and a zinc plant to produce lead and zinc metals. By-product
metals of cadmium, gold, silver and copper are also recovered. Sulfuric
acid from the metallurgical operations is used to produce phosphoric acid
and phosphate fertilizer at a phosphate complex operated as a joint venture
between Bunker Hill Company and Stauffer Chemical Company. Details on the
various process operations are discussed herein.
PROCESS OPERATIONS t
Mining
Mining activities are conducted over a vertical distance of approximately
one mile along the Bunker Hill ore body. Mining is conducted on approximately
23 levels generally spaced 200 feet apart vertically. Haulage is predominantly
through the Kellogg Tunnel (Mo. 9 level) which is the main haulage level for
the mine. The lowest active level is about 1600 feet beneath sea level. Mine
production at the rate of 2900 tons/day of ore takes place 5 days/week with
weekends being devoted primarily to repair work. The mine consists of about
500 miles of drift of which approximately 200 miles are active. Other minor
haulage is done through a portal in the Wardner area, where zinc ore which
has previously been placed as "gob" in old silver workings is recovered.
Silver ore is mined in the Crescent Mine upstream of Kellogg [Figure 1].
There appears to be a change in type of ore above and below Level 9,
i.e., the Kellogg Tunnel level. The ore above Level 9 has high zinc and
low lead content, while ore beneath the Kellogg Tunnel level is predominantly
lead, with lower zinc content. About 1000 tons/day of high grade lead ore
are mined.
Various mining techniques are employed in the Bunker Hill mine, depending
on the strength of the rock and the over-burden pressure. Most of the mining
is with cut-and-fill vertical stopping, utilizing "Bunker Hill square sets"
with sand back-fill for subsidence prevention. Sand is derived from the
sand fraction of the Bunker Hill mill tailings and is hydraulically trans-
ported and placed in the mine.
The. Bunker Hill mine is the only mine in the Coeur d1 Alene district
having significant water inflows, i.e., continuous pumping is required.
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-3-
Accorcling to company officials, it appears that most of this water inflow
is in the area of old v/orkings immediately under Milo Creek. A recent
technical paper* discusses how Bunker Hill plans to prevent and intercept
infiltration before it contacts mineralized rocks in the old stopped areas.
Company officials did not provide any information on the implementation
of these plans.
Wastewater from the mining activities originate from two sources:
1) the mine water inflow which is pumped from sumps to gravity drainage
through the Kellogg portal; and 2) the water used in transporting the
sand portion of the tailings back to the mine. This latter wastewater
should be similar in chemical composition to that water discharged from
the mill into the Central Impoundment Area (CIA). The wastewater leaving
the Kellogg portal by gravity drainage enters a closed conduit and flows
by gravity to the CIA where it enters through a port located in the center
of the pond. The only access to the mine drainage channel is at the mouth
of the Kellogg Tunnel. Company officials indicated there should be no
other inflows into this line between the tunnel and the CIA. The flow
from the tunnel varies in accord with weather conditions. Estimated flows-
of 2000-3000 gpm were given.
Milling
The Bunker Hill Company mill has a 2500 ton/day rated capacity. Mined
ore is conveyed to primary crushers and thence into secondary crushers.
Crushing takes place on two of the three shifts. Following crushing the
material goes into storage and from there it is fed to the concentrator
or flotation mill [Figure Ij. Further crushing is necessary and this is
accomplished by grinding in four sections of 8' x 10' ball mills with
spiral classifiers used to remove oversized particles. The fine particles
are mixed with water into a slurry called pulp of approximately 50% solids.
Pulp from the spiral classifiers is first sent to lead flotation cells.
Soda ash, sodium cyanide, zinc sulfate and xanthate are added and the lead
sulfide particles floated out of the pulp. The company has a meter on the
lead flotation circuit to monitor pH which is controlled with lime or soda
ash. At the tine of the tour, this circuit was being operated at a pH slightly
less than 7.
The lead sulfide froth is concentrated in a thickener with the thickener
underflow going to vacuum filters. The filtered lead concentrate with about
92 moisture is conveyed to railroad cars for transport to the lead smelter.
The underflow from the lead flotation cells is conditioned with copper
sulfate and lime and pumped into zinc flotation cells. The froth collects
zinc sulfide minerals which are floated off and then enters a thickener
from which the underflow goes to a vacuum filter. The filtered zinc
*Trexlcr, B. D., Jr.; Ralston, D. R.; Renison, VI. R.; and Vlilliams, R. E.,
Ouly 1, 1974, "The Hydrology of an Acid Mine Drainage Problem" provided at
the American Water Resources National Symposium on Water Resource Problems
Related to Mining, Colorado School of Mines, July 1-3, 1974.
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-4-
concentrate, with about '\2% moisture, subsequently is conveyed to rail-
road cars and to the zinc plant for further processing.
The underflov; from the zinc flotation cells flow to a series of four
cyclones. These cyclones make a size separation of approximately 200 mesh.
The sand fraction is returned to the Kellogg Tunnel as a 50% slurry for
backfilling operations. According to company officials the Bunker Hill
Mine is one of the few mines in the district which has excess sandfill
because only the lower stopes are backfilled. Slimes from the cyclones
drop to a sump and are pumped to discharge ports around the periphery of
the CIA.
Water from the flotation air compressors and from cooling serves as
the primary source for milling operations. This compressor and cooling
water is obtained from wells along the South Fork of the Coeur d1 Alene
River and from a spring known as Miners Slough. The make-up water for the
concentrator, approximately 1/2 gallon/minute/ton of ore, is obtained
from the Central Treatment Plant (CTP) located adjacent to the CIA.
Waste from the concentrator consists of the slimes, sand, concentrate
filtrate and concentrate thickener overflows. There is approximately a 50%
split of slimes and sand in the cyclone with the latter material as mentioned
previously being pumped to the mine. The slimes are conveyed to the CIA
using concentrator tailings water and discharged with thickener overflows.
During sandfilling operations the flow from the concentrator building to
the CIA was given as 450 gpm increasing to 800 gpm when sandfil'ling is not
In progress. The company analyzes the slimes to ascertain the loss of metals
values but, according to company officials, no attempt is made to determine
exact volumes of slimes or thickener overflows. The only point of access
for representative sampling of the combined wastewater flow appeared to be
the peripheral discharge into the CIA.
Lead Smelter
The Bunker Hill lead smelter operations were described by company
officials as being typical. The smelter has a rated capacity of 130,000
tons of metallic lead. Concentrate from the Bunker Hill concentrator
discussed above and concentrates purchased on a custom basis from sources
within and outside the United States are the feed stock for the smelter.
The concentrates are blended to achieve a uniform mixture. A charge,
consisting of concentrate, crushed ore, ferric flux and limestone is
prepared and pelletized. This mixture is conveyed to a sintering plant
for sulfur removal and for agglomeration. In the first phase of sintering
a high strength S02 gas (estimated volume of 35,000 cfm) is formed. This
gas is fed to the sulphuric acid plant. Low strength $62 gas of similar
volume is produced in the final phase of sintering. This gas is discharged
directly to the environment after wet scrubbing.
Following sintering, the material is mixed with coke and conveyed to
the top of the Bunker Hill blast furnaces. The oxygen enriched blast furnace
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-5-
has a rated capacity of 400 tons/day with the final product being generally
in the form of 100 Ib/ingots. Lead bouillon is continuously tapped off the
furnace with intermittent tapping of the slag for subsequent zinc fuming
and recovery.
The lead bouillon is refined through a number of steps to produce
pure lead metal and to remove other valuable metals. The first step is
cooling, which causes the copper to rise to the surface where it is skimmed
off as a copper dross for further smelting in a reverberatory furnace.
After removal of the copper dross, arsenic and antimony are removed
through oxidation in the next skimming. Electric furnaces treat this
material to produce an arsenical-antimonical lead known as hard lead,
which is sold to ammunition, battery and chemical manufacturers.
Gold and silver, in the form of gold and silver drosses, are then
removed through the addition of zinc metal. These drosses are refined
with the zinc being recovered and returned to the circuit. Pure gold and
silver are sold as by-products. The final step in lead purification is
vacuum dezincing, in which zinc is evaporated from the lead and deposited
as metallic zinc on a condenser.
Primary water uses in the smelter are cooling waters for the blast
furnace (jacket cooling water), fuming plant and the acid plant and gas
scrubber waters.
Little information was furnished on the water pollution aspects of
the lead smelter. A small lime treatment plant treats water from the
lead smelter. This facility was not visited during the reconnaissance.
From the lime plant, wastewaters are discharged into Sweeney Pond which
is an irregular-shaped settling basin, an estimated 300 feet in length
and 40 to 50 feet wide [Figure 1]. The overflow from this pond is re-
cycled to the smelter or pumped directly to the CIA through a 12" PVC
pipeline.
Flow from Sweeney Pond is over a concrete wall about 6" thick into
a wet well. Four pumps (capacity 1250 gpm each) are available to handle
the Sweeney Pond effluent. Effluent is pumped to the smelter as required,
with the remainder going into the CIA. The estimated average rate of flow
to the CIA was stated to be 3500 gpm.
The company monitors the Sweeney Pond discharge for process control
purposes using a continuous sampling device. Samples are analyzed for
lead, zinc and cadmium and the pH is determined.
In the recent past, excess flows from Sweeney Pond entered a concrete
channel and flowed several hundred feet to discharge into Silver King Creek
(Government Gulch). This discharge known as Outfall 003 has been "eliminated",
However, it was learned that Sweeney Pond effluent has discharged through
this outfall line on a number of occasions the past year. At the time of
the reconnaissance, it was observed that the downstream end of this discharge
-------
-D-
line was full of debris. Flow through this line is still possible and,
in the event of pump failure, could occur.
Zinc Plant
The zinc plant receives both zinc concentrates from the Bunker Hill
concentrator and concentrates purchased from other sources, including
foreign concentrates. Processing within the zinc plant starts with a
sulfuric acid leach of those zinc concentrates containing sufficient dolo-
mitic material (magnesium-calcium carbonate) to require magnesium or calcium
removal before zinc recovery. The treated concentrates and other low-
carbonate zinc concentrates are then coming!ed and sent to roasters.
Bunker Hill operates four flash roasters and one suspended bed roaster.
The company has two acid plants at the zinc plant. One acid plant treats
the effluent from the four flash roasters; the other treats the discharge
from the suspended bed roaster. Each acid plant has the capacity of pro-
ducing 350 tons/day of sulfuric acid.
The calcine from the roasters is - oled in water-jacketed screw
conveyors. This cooled calcine is the leached with spent electrolite
from the zinc cell electrowinning roorr.s and the leach solution is filtered
through Burt* Filters. Residue from the leach solution contains lead, gold
and silver, which is shipped to the lead smelter for further refining.
The Burt Filter filtrate is treated by zinc dust for removal of
cadmium, cobalt, nickel, antimony and arsenic. Following each stage of
zinc dust addition, the solution is filtered. Residue from the first two
filtrations is processed through the cadmium plant. Residues from the
other stages are returned to the first purification stage. The cadmium-rich
residue is leached with spent electrolyte and copper is filtered out.
Cadmium is precipitated with zinc dust and redissolved. A pure cadmium
metal is recovered by electrolysis.
The purified zinc solution is pumped to the cell room, where zinc is
recovered on aluminum cathodes. These cathodes are mechanically pulled
and the zinc is stripped. The stripped zinc is then sent to primary melting
furnaces for casting of 99.99+% pure zinc metal.
Wastewaters generated during zinc plant operations are piped to a
settling pond located on the opposite side of Silver King Creek. This
pond is an estimated 150 feet long by 75 feet wide. The origin of all
wastewaters entering this pond was not disclosed but probably is largely
from pretreatment operations in the zinc plant. The pond surface was
covered with what appeared to be zinc sulfide concentrate and the discharge
from the pond contained high concentrations of solids. The pond discharge,
which is piped to the CIA, represents the major input of zinc to the CIA
and the biggest single metallurgical loss to the company. Sludge from
the settling pond is recycled back to the zinc plant.
*Trade name.
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-7-
According to company officials, all electrolytic solutions are re-
cycled within the zinc plant. However, there are a number of floor drains
which can receive wastes and spills from these operations.
The S02 gas resulting from the zinc roasters is captured and cleaned
with Peabody scrubbers and is then converted to sulfuric acid. The waste-
waters from the scrubbers discharge into a drop basin at the end of the
zinc settling pond. The scrubber waters mix with the pond overflow and
both are carried in a closed conduit to the CIA, discharging freely into
the latter through a 12" PVC pipe. According to a company official, the
Peabody scrubber wastes have a S02 concentration of about-2.5%.* 'An "estimate
of the scrubber flows was stated as 100-150 gpm. The flow'leaves the pond
over a broad-crested rectangular weir about 2 feet in width with side con-
tractions of about 3 inches. Just downstream of the weir is a fiberglass
bar-screen. No flow figures or monitoring data were provided by the company
during the visit.
Silver King Creek flows through the plant property and for a distance
of several hundred yards the channel is covered with heavy timber. The
channel is 4 feet deep by about 5 feet wide. During the time of the re-
connaissance, the flow in Silver King Creek was very small. Most of Silver
King Creek water is diverted into the main company reservoir about 3/4 of
a mile upstream. Waste flows, if any, enter Silver King Creek under the
covered section and were not determined during the visit. Studies by EPA,
Region X, have shown increases in zinc, cadmium and copper in this reach
of the stream from a point above the covered channel to just above Outfall
004. According to a company official, there are no longer any discharges
into Silver King Creek, except for those permitted (i.e., Outfall 004).
There was ample physical evidence that highly corrosive wastes had
been discharged to the concrete lined Silver King Creek channel in the past.
Heavy rust-colored stains were also in evidence along the channel bottom.
The company has placed a rectangular, broad-crested weir across Silver
King Creek just upstream of Outfall 004. This flow measurement device was
required by a Section 308 request dated February 20, 1975 which, in addition,
required heavy metals sampling and flow measurement at numerous locations
and discharge points along Silver King Creek upstream and downstream of the
zinc plant.
Cooling water from the sulfuric acid production facilities is the only
NPDES permitted discharge from the zinc plant. Permit limitations on this
discharge allow no increase in the lead and zinc concentrations across the
heat exchangers (i.e., cooling towers). The cooling waters flow through a
series of drop manholes to eventually discharge to Silver King Creek. It
was noted during the reconnaissance that other flows described by a company
official as cooling water enters the discharge line. However, no data on
the quality and quantity of these other inputs were available.
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-8-
At the point where the discharge line (004) enters Silver King Creek,
a weir box approximately 36 inches wide has been constructed of 2 inch
lumber. The v/astcwater passes over a rectangular broad-crested suppressed
weir v;hich is used to measure the flow continuously.
The 004 discharge is also the subject of an EPA Compliance Order
dated September 17, 1974, in which the company was ordered to locate and
measure the total quantities of flow and heavy metals contributing to the
004 discharge line. The order emphasized that all contaminated wastewaters
formerly going to Outfall 004 were to be eliminated by Hay 1, 1974. A
subsequent order dated October 21, 1974, ordered the company to segregate
the contaminated wastewaters from 004 and discharge these to the CIA by
October 31, 1974. In a letter dated February 13, 1975*, the company stated
that waters entering Outfall 004 included blowdown from the acid plant
cooling towers (flows vary from 200-900 gpm); mill water tank overflow and
hillside runoff; overflow from the blowdown surge storage (20 gpm); runoff
waters from grounds and building roofs (5 gpm estimated); roaster floor
drains (approximately 50 gpm); cooling water overflows from the flash
roaster calcine screw conveyors (100-200 gpm); leach floor drain (75 gpm);*.
road drain which diverts storm water; cooling water from zinc coating
operations (average 20 gpm); #5 roaster cooling water (average 50 gpm);
rectifier cooling waters (200-300 gpm); and groundwater inflow into an
older section of existing concrete line. The company in a subsequent letter
dated April 28, 1975, described its plan for eliminating zinc containing
wastewaters from Outfall 004. However, the EPA review of the plan pointed
out that the plan did not address itself to a reduction of other heavy
metals, particularly cadmium. The 004 discharge has been found to be the
major point source of cadmium into the South Fork of the Coeur d' Alene
River.
Phosphate Plant
The phosphate plant is located immediately downstream of the zinc
plant on Silver King Creek. The plant operates three shifts and is pre-
sently operating a 10-days on, 4-days off schedule.- Approximately 50 people
are employed over the three-shift period. The primary products from this
operation are phosphoric acid and pellet-type fertilizers of varying
mixtures of nitrogen and phosphorus. Phosphate rock, anhydrous ammonia
and sulfuric acid are the chief raw materials.
In the production of phosphoric acid, the sulfuric acid produced at
the zinc plant is reacted with phosphate rock shipped from Southern Idaho
or Wyoming. The reaction products, consisting of phosphoric acid and by-
product gypsum, are separated by filtration on a til ting-pan filter. Gypsum
is rinsed in a countercurrent flow with the strong rinse water used for
sulfuric acid dilution. The gypsum slurry is transported to a closed
portion of the CIA, utilizing contaminated water for slurry transport.
*Letter dated February 13, 1975, Mr. G. M. Baker, Vice President, Environmental
Affairs Division, The Bunker Hill Company to Mr. Leonard A. Miller, Director,
Enforcement Division, Region X, U. S. EPA.
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-9-
Thc contaminated water is returned to the fertilizer plant for reuse in
slurrying and as feed for evaporators and barometric condensers in the
phosphoric acid circuit. Fresh water for the phosphate mill comes from
the reservoir supplied directly by North Fork and South Fork Coeur d' Alene
wells.
About 90% of the wastewaters generated in the phosphate plant come
from the filter building, according to the plant superintendent. This
includes condenser waters and other contaminated waters. The company's
attempt- to measure wastewater flow from the filter building using a
Parshall flume proved unsuccessful because of the high velocity and tur-
bulence at the point of attempted measurement.* Monitoring for process
control is conducted on the discharge to the gypsum pond. At the monitoring
point, all wastewaters, including sanitary wastes, are combined. The
specific parameters monitored were not disclosed. The estimated flow
figure provided was 1500 gpm to the gypsum pond.
The NPDES permit allows no discharges directly to Silver King Creek
from the phosphate plant. Immediately downstream from the phosphate plant?,,
wastewaters described as being from the sulfuric acid storage area enter a
concrete box about 4 feet by 4 feet. Flow into the box is through a 26 inch
concrete pipe, which showed evidence of carrying corrosive wastes as did
the concrete box. Wastewater exits from the box through a 6 inch pipe,
which discharges downstream into the closed conduit carrying zinc plant
settling pond and Peabody scrubber wastewaters. Past surveys by EPA5
Region X, indicated overflows from the concrete box have contributed
zinc, cadmium and copper to Silver King Creek.
WASTE TREATMENT SYSTEM
Central Impoundment Area
As discussed earlier, wastewaters of varying quality and quantity
from mining and milling operations, zinc plant operations after settling,
phosphate plant operations and the lead smelter after lime treatment and
settling (via Sweeney Pond) are discharged to the Central Impoundment Area
at various locations. The CIA is constructed on the alluvium of the South
Fork Coeur d1 Alene River flood plain. The dikes are constructed of mine
waste rock with a peripheral discharge of concentrator slimes intended as
a sealant. Initially the CIA was constructed to settle concentrator solids,
but other process wastes now enter it. A portion of the CIA has been diked
off and serves as a closed system for settling phosphate plant wastes, i.e.,
primarily gypsum solids. The decanted contaminated water is returned to
the phosphate plant.
*0pen portion of the discharge channel just outside the filter building. The
open channel is at the bottom of a dry well about 20 feet by 5 feet covered
with heavy planking. The well is about 8 feet deep. A fiberglass Parshall
flume was placed just downstream from the discharge pipe leaving the building.
Approach conditions proved unsatisfactory for this device.
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-10-
Tho CIA was originally constructed to discharge directly to the South
Fork of the Coeur d1 Alcne River through two decant structures. This prac-
tice was discontinued when the Central Treatment Plant v/as constructed to treat
the CIA decant. A visible examination of the toe of the CIA embankment,
adjacent to and parallel to the South Fork Coeur d1 Alcne River, showed that
leakage or piping around the two abandoned decant lines is highly probable.
An investigation of these probable seepage areas should be undertaken to
determine the quality and quantity of seepage from the CIA.
Little is known about the presence and amount of radioactivity and
fluorides contained in the wastewaters generated at Bunker Hill. Ground
waters in the vicinity of the CIA and wells along the South Fork of the
Coeur d1 A!ens River downstream need to be examined for these pollutants
and their ultimate fate.
The CIA is also the site of ferric oxide flux quarrying. The quarrying
site is east of the phosphate pond and is protected from flooding by dikes.
Smelter slag is conveyed in slurry form to waste piles located on the
west end of the CIA. At the time of this reconnaissance, there were no
surface discharges apparent from the slag waste pile area. Surface discharges
from the slag pile have been observed and monitored during EPA, Region X,
surveys.
Central Treatment Plant
The decant from the CIA is piped to the Central Treatment Plant (CTP)
located southeast of the CIA, adjacent to the mill concentrator building.
The decant is first mixed with lime slurry to aid precipitation. This
process is followed by aeration for iron oxidation. Provision has been
made for flocculation immediately following aeration, but this process was
not in operation at the time of the reconnaissance. The present flow pattern
is from the aeration tank to the larger thickener (4.5 million gallons) and
then to a large concrete basin. Solids collected in the thickeners are
presently returned to the tailings pond. Effluent leaves the concrete
basin over a 6-1/2 foot sharp-crested rectangular weir. Solids, presumably
metal precipitates, were observed going over the weir.
The company monitors the CTP influent and effluent continuously for
pH and flow. Continuous composite samples are collected at both locations,
Two small discharges were observed entering Bunker Creek from the south
side upstream of the CTP discharge. The discharge furthest upstream of the
latter discharge (about 300 yards) was oily and milky, similar in color to
coolant liquids used in machine shops. The next discharge was clear and
described by a company official as only hill drainage.
NPDES MONITORING REQUIREMENTS
The NPDES permit (issued September 30, 1973, expiration date June 30,
1976} contains effluent limitations [Table 1] on the following discharges:
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-n-
1. CIA - Discharge from the Central Treatment Plant*;
2. 004 - Cooling v/ater discharges from the primary smelting and
refining of zinc; and
3. 008 - Discharge to Silver King Creek (Government Gulch) of
excess water from the company reservoir. This is a three-basin
reservoir supplied by wells located along the North and South
Forks of the Coeur d1 Alene River. The outside basins are
supplied only with North Fork well v/ater described as being of
excellent quality. The outer basins overflow into the center
basin which receives South Fork well water high in metals.
The overflow to Silver King Creek is from the center basin and
varies in quality depending on how much South Fork well water
is pumped. The company plans to put the South Fork wells on
standby, thus the overflow from the reservoir will be essentially
North Fork well water.
»
The permit requires that drainage from the slag pile be blended with
the CIA effluent prior to its discharge into the South Fork of the Coeur
d1 Alene River. Haste streams from the slag pile flow to Bunker Creek
downstream of the CIA discharge, but upstream about 1/4 mile of the Bunker
Creek mouth. The permit contains no limitations on the blended waste flows,
EPA COMPLIANCE MONITORING ACTIVITIES
Numerous receiving water and point source studies have been conducted
since the issuance of the MPDES permit. These studies have revealed a
number of unpermitted discharges contributing heavy metals to the South
Fork of the Coeur d1 Alene River. The studies have also shown heavy metal
increase due to seepage in that reach of the South Fork Coeur d1 Alene
River running parallel to the Central Impoundment Area. Moreover, the
studies have shown that the discharge from 004 is,still contaminated and
therefore was and still is in violation of the permit compliance schedule
requiring all contaminated wastewaters to be removed from the 004 discharge
by May 1, 1974. These study findings have been the basis for compliance
orders, 308 requests and more recently, the filing of civil action against
the Bunker Hill Company.
*The CIA outfall is defined to include a composite of all discharges from
former discharge points designated as Outfalls 002, 003, 005, 006, 007 and
the contaminated portion of the effluent formerly discharged through 004.
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TABLE 1
Final Effluent Limitations for
NPDES Permitted Discharges, Bunker Hill Company
Kellogg, Idaho
Effluent
Characteristic1
Flow
Dissolved Zinc
Dissolved )
Cadmi urn. )
Dissolved )
Copper )
Dissolved Lead)
Total Mercury
Suspended
Solids
Total Phosphorus
t
008 Flow
Dissolved Zinc2)
Dissolved Lead )
Temperature
(004 only)
Discharge Limitation
Daily Average Dai1y Maximum
40,500 cu m/d 60,600 cu m/d
(10.7 MGD) (16.0 MGD)
0.85 mg/1 1.7 mg/1
(35 kg/day) (70 kg/day)
Combined total Combined total
not to exceed not to exceed
1.0 mg/1 1.5 mg/1
(40.5 kg/day) (60.7 kg/day)
0.23 kg/day 0.34 kg/day
(0.5 Ibs/day) (0.75 Ibs/day)
40 mg/1 60 mg/1
(1,620 kg/day) (2,430 kg/day)
1.0 mg/1 1.5 mg/1
(40.5 kg/day) (60.7 kg/day)
Mo net increase above back-
ground
Monitoring Requirements
Measurement Sample
Frequency Typo
Continuous
Twice Weekly 24-hr
composites
Twice Weekly 24-hr
composites
Twice Weekly 24-hr
composites
Daily
Grab
Twice Weekly 24-hr
composites
Monthly
Monthly
Monthly
Monthly
Grab
Grab
Grab
IpH shall not be less than 6.0 nor greater than 9.0. The pH of the CIA discharge
1 be monitored continuously.
Inet increase above background is interpreted to mean no increase in dissolved
and lead across the heat exchanging unit. Samples to be taken at the inlet and
tlet of unit for determining compliance.
-------
C ^_^C1 ^r^^^^r
" - Sv/ceney Pond
E - CIA - East End
F - CIA - V.'cst End
(Phosphate Plant Wastes)
G - Slcg Pile
H - Central Treatment Plant
(Outfall CIA)
I - Phosphorous Plant
J - Zinc Plant
K - Zinc Plant Settling
Pond
L - Water Supply Reservoir
(Cutfall 003)
----N;/ -
FIGURE 1, LOCATION TAD - BUNKER HILL Cnf-TANY, KELLOGG,
Courtesy of Bunker Hill Co.
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APPENDIX B
Chain of Custody Procedures
-------
ENVIRONMENTAL PROTECTION AGENCY
Office Of Enforcement
NATIONAL ENFORCEMENT INVESTIGATIONS CENTER
Building 53, Dox 25227, D'.-nvor Fcderol Ccntor
Denver, Colorodo 00225
July 24, 1974
CHAIN OF CUSTODY PROCEDURES
General:
The evidence gathering portion of a survey should be characterized by the
minimum number of samples required to give a fair representation of the
effluent or water body from v/hich taken. To the extent possible, the quan-
tity of samples and sample locations will be determined prior to the survey.
Chain of Custody procedures must be followed to maintain the documentation
necessary to trace sample possession from the time taken until the evidence
Is introduced into court. A sample is in your "custody" if:
1. It is in your actual physical possession, or
2. It is in your view, after being in your physical possession, or
3. It was in your physical possession and then you locked it up in
a manner so that no one could tamper v/ith it.
All survey participants v/ill receive a copy of the survey study plan and v/ill
be knowledgeable of its contents prior to the survey. A pre-survey briefing
Will be held to re-appraise all participants of the survey objectives, sample
locations and Chain of Custody procedures. After all Chain of Custody samples
are collected, a de-briefing v/ill be held in the field to determine adherence
to Chain of Custody procedures and whether additional evidence type samples
are required.
Sample Collection:
1. To the maximum extent achievable, as few people as possible should
handle the sample.
2. Stream and effluent samples shall be obtained, using standard field
sampling techniques.
3. Sample tags (Exhibit I) shall be securely attached to the sample
. container at the time the complete sample is collected and shall
contain, at a minimum, the following information: station number,
Station location, date taken, time taken, type of sample, sequence
number (first sample of the day - sequence Ho. 1, second sample -
Sequence No. 2, etc.), analyses required and samplers. The tags
must be legibly filled out in ballpoint (waterproof ink).
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Chain of Custody Procedures (Continued)
Sample Collection (Continued)
4. Blank samples shall also be taken with preservatives v/hich will
be analyzed by the laboratory to exclude the possibility of
container or preservative contamination.
5. A pre-printed, bound Field Data Record logbook shall be main-
tained to record field measurements and other pertinent infor-
mation necessary to refresh the sampler's memory in the event
.. he later takes the stand to testify regarding his action's
during the evidence gathering activity. A separate set of field
notebooks shall be maintained for each survey and stored in a
safe place where they could be protected and accounted for at
all times. Standard formats (Exhibits II and III) have been
established to minimize field entries and include the date, time,
survey, type of samples taken, volume of each sample, type of
analysis, sample numbers, preservatives, sample location and
field measurements such as temperature, conductivity, DO, pH,
flow and any other pertinent information or observations.. The
entries shall be signed by the field sampler. The preparation
and conservation of the field logbooks during the survey will
be the responsibility of the survey coordinator. Once the
survey is complete, field logs will be retained by the survey
coordinator, or his designated representative, as a part of the
"permanent record.
6» The field sampler is responsible for the care and custody of the
s'amples collected until properly dispatched to the receiving lab-
oratory or turned over to an assigned custodian. He must assure
that each container is in his physical possession or in his view
at all times, or locked in such a place and manner that no one can
tamper with it. _^
7. Colored slides or photographs should be taken which would visually
show the outfall sample location and any water pollution to sub-
stantiate any conclusions of the investigation. Written documenta-
tion on the back of the photo should include the signature of the
photographer, time, date and site location. Photographs of this
nature, which may be used as evidence, shall also be handled
recognizing Chain of Custody procedures to prevent alteration.
Transfer of Custody and Shipment:
1. Samples will be accompanied by a Chain of Custody Record which
. .Includes the name of the survey, samplers signatures, station
number, station location, date, time, type of sample, sequence
.number, number of containers and analyses required (Fig. IV).
When turning over the possession of samples, the transferor and
transferee will sign, date and time the sheet. This record sheet
-------
'Chain of Custody Procedures (Continued)
allows transfer of custody of a group of samples in the field,
to the mobile laboratory or when samples are dispatched to the
NFIC - Denver laboratory. When transferring a portion of the
samples identified on the sheet to the field mobile laboratory,
the individual samples must be noted in the column with the
signature of the person relinquishing the samples. The field
laboratory person receiving the samples will acknowledge receipt
by signing in the appropriate column.
2. The field custodian or field sampler, if a custodian has not
been assigned, will have the responsibility of properly pack-
aging and dispatching samples to the proper laboratory for
analysis. The "Dispatch" portion of the Chain of Custody Record
shall be properly filled out, dated, and signed.
-3.- Samples will be properly packed in shipment containers such as
1ce chests, to avoid breakage. The shipping containers will be
padlocked for shipment to the receiving laboratory.
4. All packages will be accompanied by the Chain of Custody Record
showing identification of the contents. The.original will accom-
pany the shipment, and a copy will be retained by the survey
coordinator.
5.' If sent by mail, register the package with return receipt request-
ed. If sent by co~~on carrier, a Government Bill of Lading should
be obtained. Receipts from post offices and bills of lading will
be retained as part of the permanent Chain of Custody documentation
6. If samples are delivered to the laboratory when appropriate person-
nel are not there to receive them, the samples must be locked in
a designated area within the laboratory in a manner so that no
one can tamper with them. The same person must then return to the
laboratory and unlock the samples and deliver custody to the
appropriate custodian.
Laboratory Custody Procedures:
1. The laboratory shall designate a "sample custodian." An alternate
will be designated in his absence. In addition, the laboratory
shall set aside a "sample storage security area." This should be
a clean, dry, isolated room which can be securely locked from the
outside.
2. All samples should be handled by the minimum possible number of
persons.
3. All incoming samples shall be received only by the custodian, who
Will indicate receipt by signing the Chain of Custody Record Sheet
-------
Chain of Custody Procedures (Continued)
accompanying the samples and retaining the sheet as permanent
records. Couriers picking up samples at the airport, post
office, etc. shall sign jointly with the laboratory custodian.
4. Immediately upon receipt, the custodian will place the sample
1n the sample room, which will be locked at all times except
when samples are removed or replaced by the custodian. To the
maximum extent possible, only the custodian should be permitted
1n the sample room.
5. The custodian shall ensure that heat-sensitive or light-sensitive
samples, or other sample materials having unusual physical
characteristics, or requiring special handling, are properly
stored and maintained.
6. Only the custodian will distribute samples to personnel who are
to perform tests.
7. The analyst will record in his laboratory notebook or analytical
worksheet, identifying information describing the sample, the
procedures performed and the results of the testing. The notes
shall be dated and indicate who performed the tests. The notes
shall be retained as a permanent record in the laboratory and
should note any abnormalities which occurred during the testing .
procedure. In the event that the person who performed the tests
1s not available as a witness at time of trial, the government
may be able to introduce the notes in evidence under the Federal
Business Records Act.
8. Standard methods of laboratory analyses shall be used as described
' in the "Guidelines Establishing Test Procedures for Analysis of
Pollutants," 38 F.R. 28758, October 16, 1973. If laboratory
personnel deviate from standard procedures, they should be prepared
to justify their decision during cross-examination.
9. Laboratory personnel are responsible for the care and custody of
the sample once it is handed over to them and should be prepared
to testify that the sample was in their possession and view or
secured in the laboratory at all times from the moment it was
received from the custodian until the tests were run.
10. Once the sample testing is completed, the unused, portion of the
sample together with all identifying tags and laboratory records,
should be returned to the custodian. The returned tagged sample
Will be retained in the sample room until it is required for trial.
Strip charts and other documentation of work will also be turned
over to the custodian.
-------
Chain of Custody Procedures (Continued)
11. Samples, tags and laboratory records of tests may be destroyed
only upon the order of the laboratory director, v/ho will first
confer with the Chief, Enforcement Specialist Office, to make
certain that the information is no longer required or the samples
have deteriorated.
-------
EXHIBIT I
/
1
2
«
«*
J
r:
v
EPA, NATIONAL ENFORCE.V.EN
Station No. Data
Station Location
BOD MelaU
5o!'£?s . . Oil an'd Groa^n
COD r>n,
_Nufricnfs , Cacf.
, OlKnr
Samplers:
T ir.'VESTlGATIOMS CENTER
Time Scquonco No.
. Grob
,. Comp.
Romarkj/Prosorvalivo:
Front
ENVIRONMENTAL PROTECTION AGENCY
OFFICE'OF ENFORCEMENT _
NATIONAL ENFORCEMENT INVESTIGATIONS CENTER.
BUILDING 53, BOX 25227, DENVER FEDERAL CENTER
DENVER, COLORADO 80225
x}
Back
-------
EXHIBIT II
:OR
SURVEY, PHASE.
DATE
;YPE OF SAMPLE.
ANALYSES REQUIRED
STATION'
NUMBER
STATION DESCRIPTION
TOTAL VOLUME ' |
TYPE CONTAINER
PRESERVATIVE '
'NUTRIENTS |
Q
O
a)
n
o
u
--
u
o
t
TOTAL SOLIDS |
U
i/)
>-
i
2
<
u;
_j
<
O
Q
»
"c.
CONDUCTIVITY* |
LU
o;
n
^
rx:
t u
N
LU
5
Of
0
li_
o
u
O
i
o
> i.
c
u
0
_ J
-
1
r.
a:
ID
UJ
t/1
<
UJ
IX'
o
n
2
<
C
1^1
<
t
, i
<
U
^i
c;
PiSllCIDLS |
khJ
iLv.rr- r-»yr.AKiir<; 1
IE/,1. A
-------
FIHLD DATA RECORD
STATION
NUMBER
DATE
TIME
TEMPERATURE
c
.
CONDUCTIVITY
/zmhoj/cm
pH
S.U.
D.O.
mg/1
GsgsKl.
or flow
Fl. orCFS
-------
C.AIUU1I IV
ENVIRONMENTAL PROTECTION AGENCY
Office Of Enforcement
NATIONAL ENFORCEMENT INVESTIGATIONS CENTER
Building 53, Box 25227, D-.-iwer federal Center
Denver, Colorado 80225
CHAIN OF CUSTODY RECORD
ffRVHY
JlAllON
DUMBER
'
-,
STATION LOCATION
DATE
;
Relinquished by: /s;uno
-------
APPENDIX C
Drill Logs of
Bunker Hill Area
Observation Wells
-------
EPA Na.. .onal
I
.__j _ j.
ect Number: I4~t
Number: Q /
1'Method: //
Log Water
JSeologist: /&<;
Date: .f//0//<-/-/t
Description
r
f^
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r~
Iject N
|e Nuinbt
rill Met
Jth
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1 -
f -
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It'
_
Jl2
~~ ~ ~ ~
JL_
lf~
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I
EPA Na^.onal
jmber: M-r6
sr: C> ZL
Enforcemen'
Dri 1 '
Project: 0
; Investigaf
Log
L,X'r'-//,//
on- .enter
£/A
Location: Zj7^s?y/. ^f Aj<"*f>(S<' &'£.t;-:
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x
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\-
EPA
k ,
|ect Number: - / T:(
,]e Number:_
Enforcemerr
Dril
, Investigat
Log
ons Center
i Locat i on :
-T-
.c t J-
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pth
Log V/ater
Description :
Geologist: /fi^jz c-
Date: ; G//°//77»
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N;
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/
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0
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/.
70
/O
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-------
p
f
EPA Na^.ona
ject Number:_
;"e Number: O
Enforcement Investigations Center
Dri 1 '
Project: fi
Log
all Method'.$"_#o_/Jc,~>
pth
iLocation:^/;/ // c.
_Dri]l Crew: /^x
£ 7.
Log Water
Description!
_Geologist: /> <<'^',> /*/
0
j;
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/ x
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f /?C
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h
fject Number:
lie Number: £
EPA Na,,ona
Enforcemen
Dri 1
(Project:
Investigat
Log
on. Center
till Method\g-''/,c//c-*->
I Location: 6'^.5'//i[/,
Drill Crew:
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Description:
Date: -.£/// //? 76
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Iject N
ole Numb
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;pth
lr =
1 =
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2r : x? £'
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Project:
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fl ,- // C//
Location: if 5"' j'. ^>fj /-/^ i^p/e
4
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lod: b ' titl(°y 7-/< *- Drill Crew: f^^i^'A > Geologist: /f,"'y^^'
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Description
Date:
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If
1
1
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Enforcemenl
DriT
; Investigati
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ons Center
I 1 LL / W* I/ X- /I
Iject Number: / TV Project: JT./-A'/- //,// c/A-
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Sjr
-------
1
tlject Ni
}'e Numbt
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jmber: /Y'C
Enforcemenl
DriV
Project: £
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Log
on_ .enter
L^/^r- /I// C /A i
,r: £, y , Location: 5'fc!' /V ^P /v^^X^/f ^v,-^^/^ <;/" J-'/c
rill Method:^" //c//f^> />- Drill Crew: f^t/njA : Geologist: /r>^>-^
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-------
Number:
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er: /7
EPA Na..ona"
A "
Geologist:"/^" -v
!Description!
Date:; S//*//
-------
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EPA Na,.onal
-' j
ject Number: / 4~C
le Number: //
Enforcemen-
DriT
. Investigat"
Log
-
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Project: ^ « ^ ^ ^ ' Yf <^ /" /V
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Location: ^;v />^-^_x»r-x-/>: //^c- /T^"'x ^, of //off-fa
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ject Uumber:
Number:
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DriT
Investigat
Log
11 Method: g » fro//**
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Project:^
'Location:
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-------
EPA Na jna
ect Number: /' f £
Method:*""/
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-i *T0-
' £> ' i^
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A
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Dri 1
Project:_
Location:
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on_ .enter
Description
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-------
ect II
! Numb
jmber: /^
EPA Na onal
k-
2r: /^-
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Dri 1 '
Project:
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Date: ; &//Z,//? 7 £
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-------
ect Number:
Mumber: /4'
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1
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DriT
, Investigat'
Log
0
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Method \S" f, c
jProject:_
I Location:
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Date: i l"
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ect NO
> Nuinbe
1 Meth
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EPA Na ona'
mber: 14-C
Enforcemen'
Dri 1
Project:
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oni, .enter
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ject NL
> Nunibc
11 Mett
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r~
jmber: / *?<
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Project:
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Log
oni, .enter
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-r: 7 ~7 ' Location: £>* /\f^ /<'*\e y /^A/^'J- /it* 7^a- 3/
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-------
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ect Number:
i Number: / /e
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Date:
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7£
Description
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ect Number: /'4~C
Number:
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Dri
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Log
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Project:
Location: -^y~
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Method: P7"
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_Drill Crew: /~//t-/f'^
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Description;
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Date: \i?//'>
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-------
EPA Na. jna
ct Number:
Number:
Method: *o ''
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Enforcemen
Dri 1
Investigat'
Log
Project:
JLocationEftgr t
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-------
ect Number:
Number:
EPA Na jna'
Enforcemen
Dril
Project:
: Investigat
Log
Center
. Location:,
Method: g";/V/0//ff*-> /^^ Drill Crew:
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Description
_Geologist: f\^' -^ <
Date: ; g//7 //? 7
£ o <'
V
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-------
ect Number:
[lumber: ;
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1 Method: #" //.//rt
Log Water
Enforcemen
Dri
: Investigation, Center
Log
Project:^
iLocation:
Drijl Crew:
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Date:;
Description
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-------
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Drill Log
jject Number: i 4-'
Number:
Method: <*'''////<; -
Project:
?Location:£t
Drill Crew: 7"
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f '//''if
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Description
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-------
ject Number:
Number: 2~
1 Method :_£
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Log Water
Enforcement Investigat
Drill Log
I Project:
Drill Crew:
on. Center
Geologist:^
"Date: I ^/>
Description
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-------
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ect Number: /_
Number: '^-f^
1 Method: s'"'/^/
Enforcement Investigat
Dril Log
on. Jenter
Project:
th
Log Water
'Location: /^ //+<*
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i Description
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Date:
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if
10
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-------
EPA Na .ona"
ect Number:
Number: \
Enforcement Investigaf
Drill Log
Project:^
Location:
L Center
1 Method: <£"//»//*-*/*. Drill Crew: f^H
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Log Water Description1
_Geologist:
Date:i
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///
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-------
EPA Na,. jna'
ect Number:_/
Number: & S
Enforcemen
Dril
Method :X"H*>
Project:_
Location:
Drill Crew:
Investigat'
Log
ons , enter
Log Water
Description!
Date:
t
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f
>".
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-------
EPA Na .ona'
ject Number:
; Number: £"
Enforcemen
Dril
]1 Method: & rv
7
f.+-
/
7
------- |