r
FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
NORM! REGION. ALASKA WATER LABORATORY
EFFECTS OF PLACER
MINING ON WATER
QUALITY IN ALASKA
February 1969
-------
EFFECTS OF PLACER MINING
ON WATER QUALITY IN ALASKA
U. S. Department of the Interior
Federal Water Pollution Control Administration
Northwest Region
Alaska Water Laboratory
College* Alaska
February 1969
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CONTENTS
Page
INTRODUCTION 1
Problem 1
Objectives and Scope 2
Acknowledgments 2
SUMMARY 4
General Findings 4
Conclusions 6
GENERAL BACKGROUND OF PLACER MINING IN ALASKA 7
Description of Geological Extent of Operations 7
Development of Placer Mining Methods 8
Impact of Placer Mining on the Economics of Alaska ... 11
EFFECTS OF PLACER MINING ON WATER QUALITY AND USES 14
General Study Methods 14
Mining Districts Study 16
Fairbanks District 16
Tolovana District 34
Iditarod District 40
Seward-Peninsula District 46
Koyukuk District 51
Wiseman District 58
TREATMENT AND CONTROL OF PLACER MINE WASTES 62
Treatment Methods in Use 62
Potential Methods 62
BIBLIOGRAPHY 65
APPENDICES % 66
A. Biological Data 66
B. Definition of Terms 82
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LIST OF TABLES
Table
1 Placer Gold Production in Alaska 11
2 Ready Bullion Creek Physiochemical and Biological 19
Data
3 Eva Creek Physiochemical and Biological Data .... 24
4 Cripple Creek Physiochemical and Biological Data . . 26
5 Fish Creek Area Physiochemical and Biological
Data 30
6 Fish Creek (Fairbanks Creek) Physiochemical and
Biological Data 32
7 Livengood Creek Area Physiochemical and Biological
Data 36
8 Otter Creek Physiochemical and Biological Data ... 43
9 Jnmachuk River Physiochemical and Biological
Data 49
10 Bear/Ida Creek (Hogatza River) Physiochemical and
Biological Data 55
11 Porcupine Creek Physiochemical and Biological
Data 61
11
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LIST OF FIGURES
Figure Page
1 Index Map Showing Mining Districts Examined .... 3
2 Elevated Sluice Box 9
3A Placer Mining Dredge 10
3B Hydraulic Stripping of Overburden 10
4 The 1967 Production of Gold in Relation to
Alaska's Other Natural Resource Products .... 13
5 Cripple Creek Area 17
6A Ready Bullion Creek Upstream from the
Ready Bullion Mine 21
6B Ready Bullion Creek Downstream from the
Ready Bullion Mine 21
7 Fish Creek Area 28
8 Livengood Creek Area 35
9 Otter Creek Area 42
10 Inmachuk River Area 48
11 Hogatza River Area 52
12A Aerial View of Hog Mine on Bear Creek 53
12B Aerial View of Bear Creek at its Confluence
with the Hogatza River 53
13 Porcupine Creek Area 59
iii
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EFFECTS OF PLACER MINING ON WATER QUALITY IN ALASKA
INTRODUCTION
Problem
In 1965, Congress passed the Water Quality Act creating the
Federal Water Pollution Control Administration (FWPCA) and requiring
the establishment of water quality standards for interstate waters.
Each state was given the task of adopting their own standard which,
in turn, had to be acceptable to the Secretary of the Interior.
In the adoption of the Alaskan water quality standards, the
following definition of pollution provided under state statute
(Section 46.05.230.5) was used:
"'Pollution' means the contamination or altering of waters
of the state in a manner which creates a nuisance or makes
waters unclean, or noxious, or impure, or unfit so that they
are actually or potentially harmful or detrimental or injurious
to public health, safety or welfare, to domestic, commercial,
industrial, or recreational use, or to livestock, wild ani-
mals, bird, fish, or other aquatic life; the results of activities
connected with gravel-washing plants and placer mining operations
are not pollution;"
The Alaskan standards were presented to the Secretary for approval
in 1967. They were accepted with three provisos, one of which was
that the section of the Alaska State Statutes excluding placer and
qravel mining as polluting activities be rescinded. The State was
f~*.
given a year tc make this deletion.
In June of 1968, the Commissioner of FWPCA requested by
memorandum that the Northwest Region undertake a technical study of
placer mining operations in Alaska as they relate to water pollution
control programs.
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Objectives and Scope
The objectives of the study undertaken were to find answers
to the following questions:
1. What is the nature and extent of placer mining activities
in Alaska?
2. What effects do placer mining operations exert on water
quality and water use?
3. What treatment and control methods are presently being
used, or could be used, for the control of placer mining wastes?
The scope of this study was confined to the State of Alaska.
In view of the great variation in geology, hydrology and mining
techniques within the state, six representative districts were
selected for study. These districts are shown on Figure 1 and are
listed below:
1. Fairbanks District
2. Tolovana District
3. Iditarod District
4. Seward Peninsula District
5. Kayukuk District
6. Wiseman District
Acknowledgments
Special thanks are extended to the following agencies and
institutions for their assistance in this study:
College of Earth Sciences and Mineral Industry, Univ. of Alaska
Institute of Water Resources Research, University of Alaska
Department of Mines and Geology, State of Alaska
Department of Fish and Game, State of Alaska
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SEWARD
PENINSULA
IDITAROD <
ANCHORAGE
Figure 1. Index Map Showing Mining Districts Examined
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SUMMARY
General Findings
1. Clear, clean and biologically productive water of excellent
quality was found in most streams above the influence of mining op-
erations and in streams where there were no mining operations.
2. Significant populations of fish and/or fish-food organisms
were found associated with the clean water above mining operations,
but were absent or found in significantly reduced numbers in the
highly turbid and silt-laden stream below mining operations.
3. Mines and mining operations can produce physical and water
quality barriers that prevent the upstream migration of fish.
4. The sediment load from one mine can interfere with the
utility of the water supply for downstream mining.
5. Hydraulic stripping operations greatly increase the loading
of suspended material as measured by turbidity, and can reduce the
oxygen level in a stream to zero.
6. When the overburden is mechanically stripped and stock-
piled, less water quality degradation results than from hydraulic
stripping operations.
7. The number of mines and total gold production in Alaska has
been declining for many years, and in 1967, the income from gold min-
ing in Alaska accounted for less than one percent of the value of total
mineral products, and less than 0.3 percent of the value of total
natural resource products.
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8. A substantial rise in the price of gold would increase the
number of placer mines in Alaska.
9. Few, if any, mines provide treatment for the wastes gener-
ated from their stripping and sluicing operations.
10. Settling ponds can be effective in improving water quality
by reducing turbidity.
11. The distribution of sluice box effluent over old placer
mine workings via numerous small streams reduces the turbidity of
the waste through the processes of sedimentation and filtration.
12. Changes in stream gradients resulting from mining operations
have in some cases caused erosion to exist for many years.
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Conclusions
1. Placer mining operations degrade downstream water quality
as evidenced by an increase in turbidity* a reduction in dissolved
oxygen (D.O,), and a resulting significant reduction of fish and fish-
food organisms.
2. The major impact on water quality from placer mining comes
from the hydraulic stripping operation.
3. The termination of mining operations does not necessarily
eliminate water quality degradation.
4. Techniques for the control of sediments from mining opera-
tions are available but are generally not being employed at the
present time.
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GENERAL BACKGROUND OF PLACER MINING IN ALASKA
Description of Geology and Extent of Operations
A placer mine is an operation that extracts a valuable mineral
from an alluvial or glacial deposit. In Alaska, most gold placer
mines are in alluvial gravels. These gravels may rest directly on
bedrock or upon an older alluvial deposit. The gold bearing gravels
may in turn be overlain by more recent deposits of alluvium* loess,
or products of mass wasting. In Alaska, this overlying material
ranges in thickness from zero to a hundred or more feet and is
commonly referred to as overburden of "muck". This overburden is
usually frozen and must be thawed before it can be removed.
Gold is found in all districts of Alaska. Heiner and Wolff -/
have compiled a list of all known mines or prospects for that portion
of Alaska north of the 65th parallel. Most of these are placer, and
gold is listed as a mineral found in at least 575 locations. Assum-
ing a similar number for that portion south of 65°N latitude, which
roughly divides the State in half, it is estimated that there are
*"*
about 1,000 locations where gold is known to occur. Although many
of these are unlikely to produce much gold profitably at the present
price, their widespread occurrence indicates the possible magnitude
of activity should gold prices rise enough to permit mine operators
to make a profit.
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Development of Placer Mining Methods
Early placer mining was largely a hand operation, involving
underground workings. The miners usually thawed the frozen ground
with wood fires, then drift-mined to remove the paydirt during
winter, and stockpiled it on the surface. During the summer, the
stockpiled gravel was sluiced to remove the gold. Because of the
small quantities of material being handled, the mining debris was
insignificant. Later, with the development and use of equipment
capable of handling large volumes of earth material, such as bull-
dozers, draglines, dredges, and hydraulic giants, placer mining
waste material increased in volume. Figure 2 shows a sluicing
operation with an elevated sluice box being fed by a dragline.
A placer mining dredge working at the Hog Mine is shown in Figure 3A.
Figure 3B shows a hydraulic giant which is used to strip overburden.
This process produces large quantities of mining debris which de-
grade the water quality of the streams draining the mining area.
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Figure 2. Elevated Sluice Box
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Figure 3A. Placer Mining Dredge
Figure 3B. Hydraulic Stripping of Overburden
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11
Impact of Placer Mining on the Economics of Alaska
The number of operating placer mines, output and the dollar value
of gold production has declined sharply during the past ten years.
Table 1, which is from the U. S. Bureau of Mines Minerals Yearbook,
shows that there were 50 active placer mines in 1967, with a production
of 22,948 troy ounces valued at $803,180. This can be contrasted with
the 1957-61 average of 93 active mines, and a production of 171,975
troy ounces valued at $6,019,132.
TABLE 1
PLACER GOLD PRODUCTION IN ALASKA ^
Year
1957-61 Average
i/
1962
1963
1964
1965
1966
1967
Minerals Yearbook
Number of
Mines
93
66
72
87
69
55
50
1966 and 1967,
Gold
Recovered
troy Ounces Value
171,975
164,966
98,362
56,284
38,686
26,532
22,948
•*-*
U. S. Bureau
$6,019,132
5,773,810
3,442,670
1,969,940
1,354,010
928,620
803,180
of Mines, Vol . 3
The decline in gold production can, in large part, be attributed
to the increasing cost of gold mining and the near uniform price of
gold received by the mine owners. This decline in placer gold pro-
duction has also reduced the impact of placer mining operations on
water quality. This condition could change almost overnight, how-
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12
ever, as any substantial increase in the price of gold would bring
many of the existing mines and new mines into production. Without
control of the effects of this industry on water quality, any major
revival of placer mining would result in serious water degradation
throughout many parts of Alaska.
Gold mining currently accounts for less than one percent of the
value of mineral production in Alaska. Figure 4 shows the relation
of gold to other mineral products and the relation of mineral products
to other resource industries. It is apparent that the income and
economic benefit of gold mining to the economy of Alaska is very small
in comparison with these other sources of income.
The income from tourism, whose potential for development is
almost unlimited - » is not shown in Figure 4. This rapidly growing
industry will probably contribute an important part of Alaska's income in
the not too distant future. The continued success of tourism and
recreation will in large part depend upon the wise management of the
State's water and wildlife resources.
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8i32»500jDOO|
IFOREST
877,700,000
NATURAL RESOURCE!
PRODUCTS
8 345,600,000
MINERAL!
8129,897,000
AGRICULTURE
85,500.000
PETROLEUM
884,644,000
MINERAL PRODUCTION
13129,897,000
COAL
$930,000
SAND a GRAVEL
OLD (Placer 8 Lode)
910,000
NATURAL GAS
$3,561,000
.HER MINERALS
8I2J69.000
Figure 4. The 1967 Production of Gold in Relation to
Alaska's Other Natural Resource Products
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14
EFFECTS OF PLACER MINING ON WATER QUALITY AND USES
General Study Methods
Six mining districts were selected for the study. These
districts are listed below and a map showing their location is shown
in Figure 1.
1. Fairbanks District
2. Tolovana District
3. Iditarod District
4. Seward Peninsula District
5. Koyukuk District
6. Wiseman District
To determine the impact of mining operations on water quality,
representative mining operations within each district were selected
and water quality monitoring stations established above and below
each mine. These stations were visited periodically and basic
physical* chemical and biological characteristics were determined for
comparative purposes. These characteristics are as follows:
*•»
1. Physical
Streamflow
Temperature
Geological character of the streambed and bank
Turbidity
2. Chemical
Dissolved Oxygen (D.O.)
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15
3. Biological
Fish
Benthos
Streamflow for the smaller streams was calculated from velocity
measurements made with a Price current meter. Flow of the larger
streams was obtained from the U. S. Geological Survey, or estimated.
Temperatures were measured with a standard mercury column thermometer.
The character of the stream bed and bank were determined by visual
observations. Turbidities which gave a relative measure of sus-
pended solids were determined in the laboratory using a Hellige —
Turbidimeter. The dissolved oxygen (D.O.) and pH were determined
in the field by use of a galvanic cell D.O. probe and a pH meter,
respectively.
The presence of fish was determined by visual observation. The
benthos and bottom sediments were collected with the use of a Surber
(square foot frame and net) Sampler or an Ekman (.25 ft,2) Dredge.
The benthic organisms were separated from the fine sediments with the
use of a fine mesh (60 meshes/inch) screen,-grossly identified as to kind
and stage of development (form), and counted in the laboratory with
a Stereo Zoom microscope. Detailed biological data for the stations
can be found in Appendix A.
a/ Use of product and company names is for identification only and
does not constitute endorsement by the U.S. Department of the
Interior or the Federal Water Pollution Control Administration.
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16
Mining Districts Study
Fairbanks District
The Fairbanks District is the most accessible because of the
number of highways and roads; therefore, most of the study effort
was concentrated in this district. Two separate areas within the
district were examined. These are the Cripple Creek Area, which
contains the Ready Bullion and the Eva Mines, and the Fish Creek
Area which contains the Fish Creek Mine.
Cripple Creek Area
This area is located approximately 8 miles west of
Fairbanks. It has a drainage basin of about 20 square miles and
is bounded by low rolling forested hills. In the mining area, a
layer of gold-bearing gravel overlies bedrock. This layer generally
ranges from 10 to 20 feet in thickness and is overlain by a permafrost
layer of silt and organic material. This overburden ranges up to
100 or more feet in thickness. Approximately 4 square miles of the
Cripple Creek Area were mined by a dredge prior to 1962.
The Ready Bullion and the Eva mines are the only active
-
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UNIVERSITY
OF ALASKA ^l
ASampling Station
Figure 5. Cripple Creek Area
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18
ranges in thickness from 12 to 20 feet. After stripping,the gravel
is moved to a sluice box at the lower end of the operation by drag-
lines and bulldozers. The tailings are dozed aside and piled on
each side of the stream course. There are no settling ponds or waste
treatment facilities, thus the fines, muck and detritus from both
the stripping and sluicing operations are flushed downstream. This
mine is normally operated from May to October by a crew of two.
Ready Bullion Creek, a secondary tributary of Cripple Creek,
was sampled on July 25, August 1, and October 3, 1968. The physio-
chemical and biological characteristics were measured at three points.
Station 1 was located above the Ready Bullion Mine, Station 2 was
located just below the influence of the mine, and Station 3 was lo-
cated approximately one-half mile downstream of Station 2. Data
pertaining to these stations are summarized in Table 2.
Ready Bullion Creek above the mine at Station 1 was com-
prised of mostly riffles and runs, with an occasional small pool. The
creek bottom was composed primarily of small rocks, gravel and coarse
sand in the riffle areas, and sand and silts over gravel in the pool
'••*
areas. Filamentous algae growths were most prevalent on the rocks.
All of the rocks and gravel supported diatom populations and most
rocks and some of the gravel supported significant populations of
various forms of aquatic insects. No fish species were observed in
the area; however, this is to be expected as migration is prevented
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TABLE 2
READY BULLION CREEK AREA
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Orgam'sms/sq.
Stati on
1
2
3
Date
(1968)
7-25
8-1
10-3
7-25
8-1
10-3
7-25
8-1
10-3
Temp.
C°
18.0
9.6
2.8
18.0
12.0
12.0
2.9
20.0
12.2
3.6
PH
8.2
7.3
7.8
7.8
7.0
7.0
i
7.4
7.6
7.4
7.7
D.O.
mg/1
9.2
11.2
11.5
3.8
0.9
0.0
10.6
2.4
0.4
10.1
Turbidity
J.T.U.
1.4
1.4
4.8
7,600
22,500
40,700
77
15,800
30,000
110
Flow
cfs.
0.7
1.3
3.4
3.4
2.7
5.3
-
No.
Kinds
7
7
0
0
~
0
0
-
No.
Forms
7
7
0
0
—
0
0
-
ft.
Number
42
360
0
0
—
0
0
-
Remarks
Very turbid,
stripping
Stripping
Stripping
Not operatin
Very turbid
Very turbid
Not operatin
muddy, bottoi
scouring
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both by the vertical drop of 80 feet at the mine face and by the
severely degraded water quality below the mine. From Table 2, it
can be seen that the D.O. values at Station 1 were quite high,
ranging from 9.2 to 11.5. It is also seen that the turbidities are
extremely low. All analyses indicate that the water at Station 1
is of excellent quality.
At Station 2, a tremendous change in water quality was
observed. No biological organisms were found at Station 2 nor were
any fish observed. A significant decrease in D.O. concentration can
be seen when comparing Stations 1 and 2. This decrease was most
probably caused by a high organic content in the overburden being
stripped off. The data for Station 2 shows an increase in turbidity
from less than 10 to 40,000 JTU. Two measurements on August 1 show
that large changes in turbidity can occur in a very short period of
time. These changes are caused by variations in the number of nozzles
in operation and the efficiency of stripping. From a mining stand-
point, the efficiency is computed by comparing the volume of material
stripped to the volume of water used. The more efficient the
stripping,the greater the concentration of solids in the effluent, and
the greater the effects on water quality. Figure 6A and 6B show the
contrast between Ready Bullion Creek above and below the Ready
Bullion Mine.
The data at Station 3 further confirms the degradation of
water quality observed at Station 2. As at Station 2, no biological
organisms were noted nor were any fish observed. The turbidities at
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Figure 6A. Ready Bullion Creek Upstream from the Ready
Bullion Mine.
Figure 6B.
Ready Bui lion Creek
Downstream from the
Ready Bullion Mine.
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22
Station 3 were much the same as at Station 2; however, the D.O.
concentrations were slightly lower at Station 3 than those measured
at Station 2.
EVA MINE: This mine is located on another small secondary
tributary to Cripple Creek. The gold-bearing gravels and overburden
at the Eva Mine are similar to those at the Ready Bullion Mine, the
gravels being approximately 10 to 15 feet thick and the overburden
from 90 to 110 feet thick.
The overburden is stripped by an "Intelligiant" •£/ type
hydraulic giant. The gravel is then processed in an elevated
sluice box fed by a dragline and a bulldozer. The tailings are
stacked in rowed piles that parallel the stream course. Stripping
operations over a period of five years, from May to October, have
been required to expose about an acre of gravel. The stripping
operation requires the part-time service of one man and the
sluicing requires the services of two men. There is no settling
or waste treatment, and the fines, muck, detritus and other debris
from the stripping and sluicing operations are flushed down Eva
Creek. Sluicing operations commenced in September 1968,
Three sampling stations were established on Eva Creek to
evaluate the impact of the Eva Creek Mine oh water quality. The
location of these stations is shown in Figure 5. Station 4 was located
a/ Use of product and company names is for identification only and
does not constitute endorsement by the U. S. Department of the
Interior or the Federal Water Pollution Control Administration.
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23
on Eva Creek just above the mine. Station 5 was located directly
below the mine, and Station 6 was approximately one mile downstream
of Station 5. Physiochemical and biological data pertaining to
these stations are tabulated in Table 3.
Eva Creek, at Station 4 above the mine flows on a gentle
gradient over a soft silty bottom. The banks are covered with low
overhanging brush. Referring to Table 3, it is seen that no
biological organisms were found at Station 4. It is also noted that
on two occasions, the turbidity at Station 4 was in the order of
200 JTU imparting a milky appearance to the creek. Even though no
biological life could be found at Station 4, the D.O. concentration
was 9.8 mg/1 or higher on all three occasions that it was measured.
Data for Station 5, located just below the mine, shows a
tremendous increase in turbidity and a total depletion of dissolved
oxygen. It should also be noted that no biological organisms could
be found at Station 5.
The water quality at Station 6 is very similar to that at
Station 5. Here, the stream bed is composed*of old gravel tailings
and a layer of silt, detritus and other debris. These sediments are
continually scoured by fluctuations of streamflow. Only a few
rooted emergent aquatic plants were noted and no fish species or
other forms of aquatic life were observed.
Dredge mining has occurred along Cripple Creek, both above
and below the confluence of Ester Creek which carries the runoff of
both Ready Bullion and Eva Creeks. A short distance up Cripple Creek
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TABLE 3
EVA CREEK
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Organisms/sq.ft.
Date
Station (1968)
4 7-24
8-1
10-3
5 7-25
8-1
6 7-24
8-1
Temp.
C°
15.0
9.0
0.3
18.5
9.6
20.0
10.4
PH
8.5
7.9
7.9
7.3
7.2
7.3
7.2
D.O.
mg/1
9.8
10.6
11.2
0.0
0.0
4.0
0.0
Turbidity
J.T.U.
29
230
200
24,700
111,000
29,000
97,500
Flow
cfs
0.3
0.4
-
0.3
2.6
0.4
2.9
No.
Kinds
0
0
0
0
0
0
0
0
No.
Forms
0
0
0
0
0
0
0
0
Number
0
0
0
0
0
0
0
0
Remarks
Clear, Silty
bottom
Milky
Milky
Very turbid,
Stripping
Very turbid,
Stripping
Very turbid,
Stripping
Very turbid,
Stripping
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25
from this confluence is Dredge Lake. This impoundment on Cripple
Creek has a surface area of around 425 acres. Monitoring stations
were established on Cripple Creek in order to see what impact
Dredge Lake has on water quality.
Station 7 was located on Cripple Creek before it enters
Dredge Lake and Station 8 was located just below the lake outlet.
A third station, Station 9, was located about seven miles further
downstream just above the confluence of Cripple Creek and the Chena
River. Figure 5 shows the location of Dredge Lake and the three
sampling points. A summary of the data for these stations is
given in Table 4.
No mining operations have existed above Station 7; how-
ever, due to upsets in the normal stream gradient caused by past
mining operations, the creek is still eroding and depositing mater-
ials in an attempt to establish a more uniform gradient. The data
shows that the turbidity of Cripple Creek above Dredge Lake, at
Station 7, was relatively high with a reading of 950 JTU. The
turbidity measured at Station 8 at the outfall of the lake was 6 JTU
indicating a major reduction across the lake. The presence of
biological organisms at Station 8 as compared to Station 7, where
none were found, indicates an improvement in water quality.
The high turbidity and absence of biological life
at Station 9 shows that the water quality at the mouth of Cripple
Creek is greatly affected by the upstream mining operations on
Ready Bullion and Eva Creeks.
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TABLE 4
CRIPPLE CREEK
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Organisms/sq.ft.
Date
Station (1968)
7 8-1
8 8-1
9 7-25
8-1
Temp.
CO
9.6
17.8
21.0
13.4
pH
7.9
7.8
7.8
7.5
D.O.
mg/1
11.0
10.8
7.2
5.0
Turbidity
J.T.U.
950
6.0
6,050
22,500
Flow
cfs
2.2
2.5
5.5
9.6
No.
Kinds
0
0
7
5
0
0
0
No.
Forms
0
0
9
5
0
0
0
Number
0
0
966
684
0
0
0
Remarks
Turbid, Silt.
Cutting new
bed, above
Clear, Red/
Brown. Diatoms
pm rpcls
Turbid, Silt,
Fine sand,
detritus and
debris
10-3 2.5 8.1 10.5 390 - - - - Muddy, bottom
eroding
INJ
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27
Fish Creek Area
The Fish Creek Area is located about 20 miles northeast
of Fairbanks. It is in an area of low hills similar to that of Cripple
Creek. The upper valley is about one-half mile wide and about three
miles long, and is forested with black spruce and some deciduous
species. Gold occurs in a 10 to 15 foot thick layer of gravel
that overlies bedrock. This gravel layer is generally overlain by
8 to 10 feet layer of permafrost.
The Fish creek Area has been dredge-mined except for
the last few claims at the head of the watershed. The only active
placer mine in the watershed is at the head of Fish Creek on a
small tributary stream. The location of this mine, the streams, and
the water quality monitoring stations are shown in Figure 7.
FISH CREEK MINE: Stripping at this mine is accomplished by two
hydraulic giants. After the overburden has been stripped off, bull-
dozers move the gravel to a dragline where it is lifted to an elevated
sluice. Tailings are piled along the stream bank below the sluice.
The mine is generally operated from May through October with a crew
of eight men.
Six water quality monitoring stations were located on
Fish Creek and the Little Chena River to ass.ess the impact of the
Fish Creek Mine on water quality. Station 1 was established
immediately upstream from the mine, Station 2 approximately three
miles below the mine, Station 3 further downstream below the confluence
of Fairbanks Creek, Station 4 just above the confluence with the
Little Chena River, Station 5 on the Little Chena River just upstream
-------
>o/0
^
r/>7*>
Cr.
noilings
FISH CREEK MINE
N
0 I
•^Sampling Station
Figure 7. Fish Creek Area
-------
29
from the mouth, of Fish Creek, and Station 6 approximately 32 miles
downstream. The data for these stations are summarized in Table 5.
The data contained in Table 5 shows that the water quality
of Fish Creek at Station 1, above the mine, was generally excellent
with high dissolved oxygen, low turbidity and an abundance of
biological organisms.
Below the mine, a definite degradation of the water quality
can be seen. At Station 2, turbidities ran as high as 6,000 and a
slight decrease in D.O. was observed over that measured at Station 1.
Although turbidities were quite high at Station 2, the data from
Station 3 and 4 show that this turbidity was greatly reduced by the
time Fish Creek reached the Little Chena River. A great reduction
in biological organisms can also be noted at Station 2 over those
measured at Station 1.
Data for Stations 5 and 6 show that the discharge of Fish
Creek had little or no measurable effect on the quality of the
Little Chena River.
Two water quality monitoring stations, Stations 7 and 8,
were established on Fairbanks Creek which is a major tributary of
Fish Creek. Figure 6 shows the location of these stations. The
data for these stations are summarized in Table 6. They show that
the water quality of Fairbanks Creek remains excellent throughout
the summer. Sportfish species were observed and most of the rocks
and exposed gravel supported diatom or green algae populations in
addition to aquatic insects.
-------
TABLE 5
FISH CREEK AREA
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Organisms/sq.ft.
Date
Station (1968)
1 7-26
8-2
8-28
9-20
2 7-26
8-2
8-28
Temp.
C°
15.0
9.5
6.5
1.5
15.6
11.0
10.0
pH
7.7
7.2
7.4
7.6
,7.9
6.8
6.7
D.O.
mg/1
10.0
11.0
12.5
13.8
9.7
10.2
10.8
Turbidity
J.T.U.
3.8
14
3.5
3.5
103
1,010
6,000
Flow
cfs
3.7
3.7
0.7
-
5.8
8.1
9.2
No.
Kinds
7
4
4
15
-
1
2
2
0
0
No.
Forms
7
4
4
15
-
1
2
2
0
0
Number
15
13
124
238
-
1
7
16
0
0
Remarks
Clear, Amber
color
Slightly milky
Clear
Clear, Icy
Turbid and
milky colored
Turbid, Stripping
Very turbid,
Stripping
CO
o
Continued on next page
-------
TABLE 5 (CONT.)
FISH CREEK AREA
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Orgam'sms/sq.ft.
Date Temp. D.O. Turbidity Flow No. No.
Station (1968) C° pH rag/1 J.T.U. cfs Kinds Forms Number Remarks
8-2 9.5 7.0 11.2
152
8-2 9.0 6.9 10.7
8-2 8.0 6.9 11.0
8-2 11.0 6.8 10.4
73
0.6
6.0
32.7 1 1 36 Turbid, Mine
stripping
8 10 112
43.4 3 3 1,144 Very milky
3 4 101
109 4 5 40 Clear. Too deep.
Sample not repre-
sentative of Benthos
Too deep to sample prope.'rly. Milky
CO
-------
TABLE 6
FISH CREEK (FAIRBANKS CREEK) AREA
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Orgarnsms/sq .f t_._
Date Temp. D.O. Turbidity Flow No. No.
Station (1968) C° pH mg/1 J.T.U. cfs Kinds Forms Number Remarks
7 7-26 14.3 8.3 10.0 3.8 6.0 99 117 Clear, Algae
Diatoms, Fish
8-28 8.8 7.3 11.6 3.0 5.1 11 11 172 Clear, Diatoms,
Fish
9-20 3.2 7.9 12.4 - - ...
8 8-2 13.5 8.0 10.5 3.3 6.6 5 5 20 Clear, Fish
5 5 29
-------
33
Summary of Findings for Fairbanks District
The investigations of the placer mining operations in the Cripple
Creek and Fish Creek areas show the following:
1. Clear, clean, biologically productive water of excellent
quality was consistently found above the mining operations in streams
examined.
2. Hydraulic stripping at the three mines examined increased the
loading of suspended material, as measured by turbidity, and reduced
the oxygen level in two cases to zero.
3. Significant populations of fish and/or fish-food organisms
were found associated with the clear water, but were absent or found
in significantly reduced numbers in the highly turbid and silt-laden
streams below mining operations.
4. Mines and mining operations can produce physical and water
quality barriers that prevent the upstream migration of fish.
5. Mines or mining operations on Cripple Creek have changed the
stream gradient to such a degree that water quality degradation from
erosion has existed for many years after the mining operations were
terminated.
6. The lower ten miles of Cripple Creek and its tributaries, and
at least seven miles of Fish Creek, are seriously degraded from
present mining operations.
7. A settling pond, such as Dredge Lake on Cripple Creek, can
be effective in improving water quality by reducing turbidity.
-------
Tolovana District
The Tolovana District is located approximately 50 miles north-
west of Fairbanks. The investigation was concentrated in the
Livengood Creek Area which contains the Amy and Livengood Mines.
The area was selected because these mines operate almost in tandem
on the same stream.
Livengood Creek Area
Livengood Creek is a tributary to the Tolovana River. The
creek valley is about a mile wide, ten miles long, and is bounded
by low hills that are forested with black spruce.
Gold occurs in a gravel layer that overlies bedrock. This
layer, which ranges from about 4 to 20 feet in thickness, is mantled
by up to 100 feet of overburden. The location of the mines, streams
and water quality monitoring stations are shown in Figure 8 and the
water quality data are summarized in Table 7.
AMY MINE: This mine is located on Amy Creek just above its
confluence with Livengood Creek. The gold-bearing gravel layer is
»-*
less than 100 feet wide and extends down the center of the valley.
The gravel ranges from 10 to 20 feet thick and is covered with 80
to 100 feet of overburden.
The mine equipment consists of a hydraulic giant used to thaw
and strip the overburden, and a bulldozer and dragline used to stock-
pile the gravel and feed the sluice box. The mine employs three
men from May to October.
-------
LIVENGOOD MINE
Tailings
'LIVENGOOD
A Sampling Station
MILES
Figure 8. Livengood Creek Area
-------
TABLE 7
LIVENGOOD CREEK AREA
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Date
Station (1968)
1 7-29
9-24
2 7-29
3 7-29
4 7-29
Temp.
C°
11.4
-1.2
17.2
13.0
11.0
pH
8.1
7.5
8.0
7.5
7.8
D.O.
rag/1
10.8
7.1
9.2
8.5
9.0
Turbidity
J.T.U.
32
42
8.4
35,000
5,620
Flow
cfs
0.2
-
Pond
0.8
2.9
Organisms/sq.ft.
No. No.
Kinds Forms Number Remarks
9 9 197 Milky colored.
Cat. work.
- - - Rock bottom gravel
Clear
1 1 10 Yellow mud
6 6 10 Yellow clay,
9-24
0.0 27.2
8.1
39
bottom-siIty
80% ice-covered
LO
-------
37
The flow of Amy Creek is so low that its flow is impounded in
a small reservoir at the mine in order to accumulate sufficient
water to operate. In 1968, the flow was so low that the hydraulic
giant could be operated for only 40 minutes each 24 hours. The
silt, muck and other debris from the stripping operation is flushed
down Amy Creek into Livengood Creek. The tailings from the sluice
box are piled along the stream.
Water quality monitoring Station 1 was established on Livengood
Creek just above the mouth of Amy Creek and Station 2 was established
at the supply reservoir at the Amy Mine. The data for these two
stations represent the natural water quality that occurs upstream
from mining operations. Turbidities at these two stations were
quite low and dissolved oxygen was high. The rocks at Station 1
supported limited populations of diatoms and green algae. Station
3 is on Livengood Creek approximately one and one-half miles below
the mouth of Amy Creek and represents water quality below the Amy
Mine. Turbidities at Station 3 measured 35,000 JTU and a slight
decrease in dissolved oxygen over values at .Stations 1 and 2 can be
seen.
LIVENGOOD MINE: This mine is located on Livengood Creek just
below Station 3. The gold-bearing gravel at this mine ranges from
about 4 to 6 feet in thickness and is covered by up to 8 feet of
overburden. As the valley is relatively wide in this area, the
gravel layer extends over a wide area. This mine generally employs
a crew of four from May to October.
-------
38
The overburden is stripped by bulldozers afterwhich the gravel
is pushed by a bulldozer to a sluice box installed in the creek
bottom. The mine operators have constructed a small reservoir to
regulate the flow to the sluice box. This reservoir was almost
full of silt that had been washed down from the Amy Mine.
At time of sampling, the Livengood Mine did not operate because
of the low water supply and the large load of suspended solids in the
water. It was reported that the water supply at the Livengood Mine
has carried suspended solids that have ranged up to 12 percent by
volume.
Station 4 is located on Livengood Creek some four miles below
the Livengood Mine. The data for this station show that the reservoir
at the Livengood Mine and the dilution from tributary streams
substantially reduces the turbidity. The turbidity at Station 4,
however, still exceeds 5,000 JTU and no biota or fish were observed.
Summary of Findings for Tolovana District
The investigation of the placer mining operations in the Liven-
good Creek area shows the following: '*
1. Clear, clean biologically productive water was found up-
stream from the influences of mining operations.
2. Hydraulic stripping on Amy Creek contributed a suspended
load to Livengood Creek that resulted in turbidities in excess of
5,000 JTU at a distance of about six miles downstream.
-------
3. Water quality degradation from stripping operations at the
Amy Mine has reduced the population and diversity of fish-food
organisms in Livengood Creek for more than six miles downstream.
4. The sediment load from the Amy Mine interfered with the
utility of the water supply for mining downstream at the Livengood
Mine.
-------
Iditarod District
The Iditarod District is located approximately 380 miles south-
west of Fairbanks in the Yukon Drainage Basin. The Otter Creek Area
was selected as being representative of this mining district.
Otter Creek Area
The Otter Creek Area consists of a long, narrow, west-trending
valley that is bounded by mountains that rise 2,000 feet or more
above the valley floor. Slate Creek is a major tributary stream
that enters Otter Creek from the south. The hills and mountains are
forested with spruce and the valley floor is a muskeg.
Placer mining activity has been intense in past years; however,
only the Slate and the Willow mines are still active. The gold is
found in a thin gravel layer that is covered with up to ten feet of
overburden.
SLATE MINE: This mine is on Slate Creek approximately one
quarter mile above its confluence with Otter Creek. The overburden
is stripped with a bulldozer and the gravel -is fed to the sluice
box with a large backhoe. The total flow of Slate Creek is passed
through the sluice box. The tailings are dispersed with the bull-
dozer. The effluent from the sluice box flows to Otter Creek
through numerous small distributaries that flow over the previous
workings. This mine is generally operated by two men from May
through October.
-------
41
Water quality monitoring Station 1 was located on Slate Creek
just upstream from the mine; Station 2 was on Otter Creek just up-
stream from the confluence of Slate Creek; Station 3 was on one of
the distributaries of Slate Creek just before it discharges into
Otter Creek; and Station 4 was on Otter Creek approximately three
miles downstream . The location of the mine, the streams, and the
water quality stations are shown in Figure 9, and the data for the
stations are summarized in Table 8.
The bottom of Slate Creek at Station 1, above the mine was
comprised of alluvial silt and sand deposits as the result of up-
stream mining operations in the past. Very sparse growths of algae
were noted and no fish species were observed. The turbidity at
Station 1 was quite low and the D.O. was high.
At Station 2, the bottom of Otter Creek was clean and covered
with small rock and coarse gravel. This substrata supported
appreciable populations of diatoms and moderate populations of
green algae. A small benthic dwelling fish (Cottus sp.) was also
collected.
Data for Station 3 shows the great change in water quality re-
sulting from the mining operation. The turbidity at Station 3
measured 3,600 JTU and a decrease in dissolved oxygen over Stations
1 and 2 can be noted. While the turbidity values measured at
Station 3 were high, they were significantly less than those
measured below similar operations. Visual observation indicates
-------
FLAT
^Sampling Station
MILES
Figure 9. Otter Creek Area
-------
TABLE 8
OTTER CREEK
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Organisms/sq.ft.
Station
1
2
3
4
Date
(1968)
8-12
8-12
8-12
8-12
Temp.
C°
19.0
17.0
20.0
18.0
pH
7.9
7.6
7.0
7.2
D.O.
rag/1
9.9
9.7
7.4
9.2
Turbidity
J.T.U.
3.5
5.0
3,600
250
Flow No.
cfs Kinds
5.8 2
8
-
8
No.
Forms
2
8
-
8
Number
48
99
-
83
Remarks
Bottom silty,
Very soft
Clear-bottom
Clean, 1 fish
Very fine
sediment
Bottom light
silt cover
CO
-------
44
this reduction was accomplished by distributing the wastes generated
over the old mine workings.
Station 4 data show a great reduction in turbidity over that
measured at Station 3. This reduction was due to further sedimenta-
tion, filtration, and dilution of the mining waste water over and
through the tailings. Station 4 also had a number of diatoms grow-
ing on si It-covered rocks.
WILLOW MINE: The Willow Mine is on Willow Creek which is a
tributary of the Iditarod River. Gold occurs in a thin layer of
gravel that is mantled with 4 to 8 feet of overburden. Bulldozers
are used to remove the overburden and move the gravel to a dragline
which feeds an elevated sluice box. Bulldozers are also used to
remove and pile the tailings.
As the flow of Willow Creek is very low, the mine operators
have constructed a small catch basin and recycle the water for their
sluicing operation. The turbidity of the water being pumped from
the catch basin to the sluice box had a turbidity of 77,000 JTU and
the effluent from the sluice box was 100,000"3TU. Mercury was used
to increase the efficiency of gold recovery in the sluice box. As
gold was still collected in the last riffle of the sluice box, it is
concluded that a high sediment load in a mine water supply reduces
the efficiency of gold removal.
-------
45
Summary of Findings for Iditarod District
1. Clear, clean, biologically productive water of high quality
was found above the mining operations on Otter and Slate Creeks.
2. The distribution of sluice box effluent over old placer
mine workings via numerous small streams below the Slate Mine re-
duced turbidities by providing sedimentation and filtration.
3. The efficiency of gold recovery at the Willow Mine was
reduced by high turbidities and suspended material in the process
water.
-------
46
Seward Peninsula District
The Seward Peninsula is the large peninsula that extends west-
ward towards Siberia, approximately 500 miles west of Fairbanks.
This is an old mining district made famous by the gold production
at Nome, which is located along the south shore of the peninsula.
Inmachuk River Area
The only mine examined on the Seward Peninsula was the Inmachuk
Mine located in the Inmachuk River Basin. This stream, which extends
about 25 miles inland, flows north and discharges into Kotzebue
Sound at Deering. The area is one of low relief with rounded ridges.
Tundra and muskeg cover most of the area along with some scrub willow
growing adjacent to the river. The valley is narrow and the stream
gradient is low, being less than 50 feet in five miles.
Gold occurs in a thin layer of gravel that is mantled with silt
and muskeg. Several idle dredges and several miles of extensive
tailing piles in the river and along the watercourse can be observed
and bear mute testimony to the extensive mining operations in the
past.
INMACHUK MINE: This mine is located on the west bank of the
river about 16 miles south of Deering.
In mining, the thin layer of overburden is removed by a bull-
dozer and piled at the edge of the valley floor. The gravel is
then fed to an off-channel sluice box supplied with water pumped
-------
47
from the river. The tailings are also pushed to the edge of the
valley floor. One man full time and four men part time are gener-
ally employed at this mine from May to October.
The effluent from the sluice box flows through a series of
six small settling ponds prior to its return to the Inmachuk River.
These ponds provide a retention time of about six hours. Water
quality monitoring Station 1 was established on the river upstream
from the mine; Station 2 was at the discharge from the sluice box;
Station 3 was at the outfall from the last settling pond; and
Station 4 was on the Inmachuk River about one mile below the mine.
Figure 10 shows the location of the stream, the Inmachuk Mine and
the water quality monitoring stations.
The data from the stations sampled are presented in Table 9.
At the time of sampling the sluicing had only been underway for a
few hours. As a result, equilibrium in the ponds had not been
achieved and the pond effluent at Station 3 is not representative
of the discharge that would occur after a sustained period of mine
operation. Conditions at Station 4 are also*not representative of
conditions during operation, but instead are similar to those when
the mine does not run.
The bottom of the Inmachuk River at both Stations 1 and 4 was
composed of loose gravel. The water was clear and colorless and
there was a complete lack of diatoms and filamentous algae at these
sites. Multiple sampling failed to show any fish-food organisms
in the river. This lack of organisms is attributed to a shifting
-------
/PEERING
10.5 MILES
I
Tailingsr"
INMACHUK
MINE
Sampling Station
MILES
I
Figure 10. Inmachuk River Area
-------
TABLE 9
INMACHUK RIVER
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Orgam'sms/sq.ft.
Date Temp. D.O. Turbidity Flow No. No.
Station (1968) C° pH rog/1 J.T.U. cfs Kinds Forms Number Remarks
1 8-13 19.0 8.5 10.2 0.2 670 000 Clear, Bottom
Loose, clean
Fish
2 8-13 18.0 7.5 9.1 16,500 6.7 -
3 8-13 19.0 8.2 9.0 1.5 8.0 - - - Bottom thinly
silted
Fish
4 8-13 18.0 8.5 9.4 0.6 1,340 000 Like at Station
1
Fish
VO
-------
50
and moving action of the bottom gravels. Several sportfish and
other fish species were observed in the river, and it was reported
that chinook and chum salmon utilize the river for spawning. Data
from Table 9 show the turbidities at both of these stations to be
very low, while dissolved oxygen is very high.
A comparison of the data for Stations 1 and 2 show the impact
of sluicing on water quality. The measured turbidity'increase of
16,500 JTU is quite significant but still less than the values of
40,000 JTU found below mines where hydraulic stripping is employed.
Summary of Findings for Seward Peninsula District
The investigation in the Seward Peninsula District shows the
following:
1. Clear, clean water was observed in the Inmachuk River
above and below the Inmachuk Mine.
2. The gravel bottom above and below the mine was barren of
diatoms and filamentous algae and fish-food organisms were absent.
3. An increase in turbidity of 16,500 JTU was measured across
the sluice box at the Inmachuk Mine.
4. The sluice box effluent from the Inmachuk Mine receives
some treatment in a series of settling ponds. The efficiency of
these ponds in removing solids under sustained loading is not
known.
5. Stripping wastes are stockpiled and there is no water
quality degradation from the stripping operation.
-------
51
Koyukuk District
The Koyukuk District is located some 250 miles northwest of
Fairbanks. The only active mining operation is that done by a
placer dredge operating in the Bear/Ida Creeks Area near the
Hogatza River. This dredge is operated by the American Smelting
Refining and Mining Company on a 2,000-acre claim that is known
as the Hog Mine. The location of the streams, Hog Mine and the
water quality monitoring stations are shown in Figure 11.
Bear/Ida Creeks Area
The Bear/Ida Creeks Area is a broad basin of low relief that
is surrounded by forested hills and mountains. Caribou Mountain*
which lies to the west, rises to an elevation of 3,000 feet and
forms the headwaters area for Bear and Ida Creeks. The basin
contains great expanses of swampy muskeg and numerous oxbow lakes.
These lakes were formed by the Hogatza River as the channel
shifted back and forth across the floodplain.
HOG MINE: This mine lies between Caribou Mountain and the
~*
Hogatza River at the man-made confluence of Bear, Ida, Dry and
Moraine Creeks. Most of the overburden in the mining area was
stripped during the late '30's and '40's. The remaining over-
burden consists of a blue clay layer that ranges from 4 to 10 feet
thick. This clay and the underlying gravels are mined and pro-
cessed by a large floating dredge which is shown in Figure 12A.
-------
5 10
^Sampling Station
Figure 11. Hogatza River Area
-------
Figure 12A. Aerial view of Hog Mine on Bear Creek showing the dredge,
dredge pond, tailings and discharge stream.
Figure 12B.
Aerial view of Bear Creek at its confluence with the
Hogatza River showing turbidity produced by the dredging
at the Hog Mine.
-------
54
The dredge-pond water supply comes from the combined flow of
Bear and Ida Creeks that is introduced at the head of the mining
operation. The dredge works in a downstream direction and the
discharge from the pond flows back to the Bear Creek channel
through a man-made ditch. A crew of 23 men are employed at this
mine which is normally operated from May to October.
Five sampling stations were established in the vicinity of
the Hog Mine in order to assess the impact of this mining opera-
tion on water quality. Figure 11 shows the location of these
stations. Station 1 was established on the combined Bear/Ida Creeks
just upstream from the mine. Station 2 was located at the head of
the dredge-pond effluent ditch. Station 3 was located on the effluent
ditch 1,500 feet downstream from Station 2. Station 4 was established
on the nearby First Creek to provide water quality information on
a stream not affected by mining operations. Station 5 was located
on the Hogatza River near its mouth, about 27 road miles down-
stream from the Hog Mine. The data for these stations are summar-
ized in Table 10.
The bottom of the Bear/Ida Creek channel at Station 1 was
clear, clean and covered by rock, gravel of various sizes, and sand.
The rock and gravel supported moderate populations of diatoms and
algae. The gravel riffle areas produced the greatest populations of
aquatic insects. Fish were not observed at this station; however,
grayling and other sportfish were observed and collected with sport
gear in both Bear and Ida Creeks about one-fourth mile above the
-------
TABLE 10
BEAR/IDA CREEK (HOGATZA RIVER)
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Organisms/sq.ft.
Date Temp. D.O.
Station (1968) C° pH raq/1
1 8-9 17.0 7.6 10.7
2 8-9 -
3 8-9 15.5 6.5 9.0
Turbidity
J.T.U.
3.8
24,000
20,000
Flow No.
cfs Kinds
8.5 9
4
11.0
11.9 0
0
No.
Forms
9
4
_
0
0
Number
67
20
_
0
0
Remarks
Clear, rock
gravel and sand.
Algae and diatoms
on rocks .
Very turbid
Firm bottom
Very turbid
Firm
Silt and gravel
bottom
8-9 9.5 7.2 12.2 0.7 10.6 10 11 187 Clear, clean
rock-gravel
bottom
8-9 19.5 7.3 9,2 156 5500 est. 33 12 Soft, silty
sand bottom
01
en
-------
56
station. Data from Table 10 shows the turbidity at Station 1 to be
low (3.8 JTU) and the dissolved oxygen to be high (10.7 mg/1).
At Stations 2 and 3, the water was extremely turbid and the
bottom was very firm and covered by partially exposed rock and
gravel which were firmly embedded in the substrata. The very high
concentration of suspended solids could be felt by hand. Some of
the eddies were completely filled with very fine silt. Algae,
diatoms, and fish-food organisms were not found at Stations 2 and 3.
This degradation of the biological life is coupled with very high
turbidities (20,000 and 24,000 JTU) measured at these two stations.
Station 4 was established on First Creek, but High Creek was
also visually examined. The water was very clear, and the bottom
was clean and clear of silt and fines. The bottom of First Creek
was covered with rock and gravel which provided good productive
habitats for fish-food organisms. Grayling up to about 14-inches
long were observed. Data for Station 4 shows a great abundance of
biological life, a very low turbidity (0.7 JTU) and high D.O.
(12.2 mg/1).
Data from Station 5 shows the Hogatza River to still be turbid
(156 JTU) about 27 miles downstream from the^mining operation.
Figure 12B shows the highly turbid water of Bear Creek entering the
Hogatza River.
-------
57
Summary of Findings for Koyufcuk. District
The results of the study in this district are:
1. Clear, clean, biologically productive water of high quality
was found above the Hog Mine and in undisturbed streams.
2. Very turbid, biologically unproductive water was discharged
from the dredging operation at the Hog Mine.
3. Clay overburden processed with the gravel was the chief
source of the very high turbidity, extremely high suspended solids
concentration, and amount of mud and silt in the dredge pond
effluent from the Hog Mine.
4. Sport and/or commercial fish species utilize the habitable
portions of the watershed.
5. Turbidity from the Hog Mine was detected some 27 miles below
the mine on the Hogatza River.
-------
58
Wiseman District
The Wiseman District is located about 200 miles north of
Fairbanks. It is a mountainous area criss-crossed by
broad valleys. There are numerous mines in the district; however,
only the Porcupine Creek Area was examined.
Porcupine Creek Area
Porcupine Creek is a short stream that is tributary to the
Middle Fork of the Koyukuk River about 14 miles downstream from
Wiseman. It drains a small, mountainous area and flows in a
narrow V-shaped valley.
Gold occurs in a thin layer of gravel alluvium that is mantled
with a thin cover of slopewash and talus. The location of Porcupine
Creek, Porcupine Mine and the water quality monitoring stations are
shown in Figure 13.
PORCUPINE MINE: This mine is located on the narrow valley
floor of Porcupine Creek approximately two miles above its junction
with the Koyukuk River. The thin overburden at the mine is stripped
with a hydraulic nozzle. The gravel is fed to an off-channel sluice
box by a bulldozer and the tailings are piled along the stream below
"•a
the mine. The overburden and the sluice box effluent are flushed down
the creek. The mine is generally operated from*May to October by
one man.
Sampling Station 1 was established above the mine. Station 2
was established 50 feet below the sluice effluent outfall. Station 3
was at the mouth of Porcupine Creek. The Middle Fork of the Koyukuk
-------
WISEMAN /
PORCUPINE MIME
MILES
'•"••••^•^
I 2
Sampling Station
Figure 13. Porcupine Creek Area
-------
60
River was sampled just upstream from the mouth of Porcupine Creek
at Station 4 and below the mouth at Station 5. The data for these
stations are summarized in Table 11.
The water in Porcupine Creek above the mine at Station 1 was
clear and very productive of fish-food organisms. The turbidity
here was very low (0.6 JTU) and the D.O. was quite high (11.8 mg/1).
At Station 2 just below the mine, a distinct change in the
water quality was noted. Here, the turbidity measured 6,600 JTU.
Biological organisms were not sampled at Station 2: however, measure-
ments made at Station 3 further downstream showed a areat reduction
over the number measured at Station 1.
Data from Stations 3 and 5 indicate that the influence of the
mine is reduced but still apparent downstream. The turbidity
measured at Station 5 was 59 JTU.
Summary of Findings for Wiseman District
The results of the study in this district are:
1. Biologically productive water of high quality was found
in Porcupine Creek above the mining operation.
2. Very turbid water with a high suspended and settleable
-i
solids content was discharged from the mining operation on Porcupine
Creek and it degraded the stream to its mouth.
-------
TABLE 11
PORCUPINE CREEK
PHYSIOCHEMICAL AND BIOLOGICAL DATA
Organisms/ sq.ft.
Station
1
2
3
4
5
Date
(1968)
8-22
8-22
8-22
8-22
8-22
Temp.
C°
7.5
7.5
12.8
12.4
12&
pH
7.3
6.8
7.3
7.5
7.5
D.O.
mg/1
11.8
n.o
10.4
11.2
11.0
Turbidity
O.T.U.
0.6
6,500
350
2.2
59
Flow No.
cfs Kinds
17 11
6
-
17 1
1
4
1
No.
Forms
12
6
-
2
1
4
1
Number
156
22
-
2
1
5
3
Remarks
Clear, clean
gravel ,rock
bottom
Very turbid
Very murky
colored
Sample not
representative
Sample not
representative
River milky
colored
-------
62
TREATMENT AND CONTROL OF PLACER MINE WASTE
Treatment Methods in Use
Wastes from placer mines are from three types of operations:
stripping, sluicing, and dredging. The dredging operation may be
a combination strippingT-sluicing operation or may just involve the
sluicing process.
The wastes generated from the stripptnp process differ from
sluicing wastes in being composed of finer sized particles and in
containing various amounts of organic material.
In general, there is little or no treatment of wastes at oper-
ating placer mines. Of the mines examined, two systems were ob-
served. One was a settling pond at the Inmachuk Mine and the other
was at the Slate Mine where the waste was distributed across the
old mine workings. Both systems provide some treatment, but data
is not available to evaluate their efficiencies.
Potential Methods
There are certain techniques and practices that would provide
some treatment of mine wastes improving water quality in receiving
streams. These would include the following:
Stripping Operations
1. Where the overburden is shallow, the material could be
stripped and stockpiled by mechanical means.
-------
63
2. Where hydraulic stripping is the only feasible method of
removing the overburden, the effluent could be discharged into
settling ponds or diverted onto abandoned tailing dumps. Where it
is not feasible to pond or spread the waste, consideration should be
given to restrict stripping to periods of time when the impact of
turbidity would be at a minimum. At some operations it may be de-
sirable to reduce the efficiency of hydraulic stripping so as to re-
duce the amount of suspended solids and turbidity in the mine effluent,
Sluicing Operations
1. The effluent from sluicing operations could be diverted
into settling ponds or spread onto abandoned tailing dumps.
2. The use of an off-channel sluice box and the reuse of
water from the settling ponds would reduce the loading to the stream
system.
3. Where ponding and spreading of sluice box effluent is not
feasible, it may be desirable to restrict sluicing operations to
particular periods of time to reduce the impact of the mine waste
on the receiving stream.
Dredging Operations
1. Dredge ponds could be off-channel or the stream could be by-
passed around the pond through a ditch or canal. Water diversions
to the pond could be controlled so that there is no surface discharge
from the pond.
-------
64
2. Where possible, dredging could proceed in an upstream direction
so that the subsurface outflow or leakage from the dredge pond would
be filtered through the tailings prior to its return to the stream
system.
-------
65
BIBLIOGRAPHY
1. Heiner, Laurence E., and Ernest N. Wolff, Final Report: Hineral
Resources of Northern Alaska, Mineral Industry Research
Laboratory, Report No. 16, June 1968.
2. U. S. Department of Commerce, Economic Development in Alaska--
A Report to the President, Federal Field Committee for
Development Planning in Alaska, August 1966.
3. Thomas, Bruce I. et al, Placer Mining in Alaska, U. S. Bureau of
Mines, Information Circular T92b, 1959.
-------
66
APPENDIX A
BIOLOGICAL DATA
-------
TABLE 1A
CRIPPLE CREEK BIOLOGICAL DATA
UdLc
Station (1968) Sampler Common Name
1 7-25 Surber Stoneflies
Mayflies
Caddisflies
True Flies
Miscellaneous
Spongue
Nematoda
8-1 Surber Stoneflies
Mayflies
Caddisflies
True Flies
Miscellaneous
Spongue
Nematoda
Ekman True Flies
Caddisflies
Organisms
Fami ly
Perlodidae
Baetidae
Limnephilidae
Tendipedidae
Simuliidae
Unknown
Unknown
Perlodidae
Baetidae
Limnephilidae
Tendipedidae
Simuliidae
Unknown
Unknown
Tendipedidae
Simuliidae
Limnephilidae
State
Nymph
Nymph
Pupae
Larvae
Larvae
Unknown
Unknown
Nymph
Nymph
Pupae
Larvae
Larvae
Unknown
Unknown
Larvae
Pupae
Larvae
Pupae
Number
11
1
2
19
4
3
2
8
1
1
337
4
7
2
9
1
3
1
Remarks
Moderate amounts
of filamentous
algae and diatoms
on rock and gravel .
Water clear. Bottom
clean.
Moderage amounts
of filamentous
algae, diatoms, and
other green algae.
Water clear. Bottom
clean. Raining this
date.
Fragments of green
algae.
Miscellaneous
Nematoda
Unknown
Unknown
CTI
-------
TABLE 1A (CONT.)
CRIPPLE CREEK BIOLOGICAL DATA
Date
Station (1968)
2 7-25
8-1
8-1
3 7-25
8-1
4 7-24
8-1
8-1
5 7-25
8-1
6 7-24
8-1
7 8-1
Sampler Common Name
Ekman
Ekman
Ekman
Ekman
Ekman
Ekman
Ekman
Ekman
Ekman
Ekman
Ekman > -
Ekman
Ekman
Surber
Orqani sms
Family State Number
0
0
0
0
0
0
0
0
0
0
0
0
0
0
Remarks
Silt and detritus.
Silt and detritus.
Silt and detritus.
Lots of silt and
detritus.
Lots of silt and
detritus.
Soft bottom
composed of silt
and some detritus.
Sand, soft silt
and lots of detritus.
Soft "rock" bottom -
pools and eddys filled
with silt and detritus
Detritus, rootlets.
Sand and lots of silt.
Detritus and rootlets.
er>
oo
-------
TABLE 1A (CONT.)
CRIPPLE CREEK BIOLOGICAL DATA
Date
Station (1968) Sampler
8 8-1 Surber
8-1 Ekman
9 7-25 Ekman
8-1 Ekman
8-1 Ekman
Common Name
Mayflies
True Flies
Miscellaneous
Nematoda
Coelenterata
Oligochaeta
Caddisflies
True Flies
Miscellaneous
Nematoda
*-
-
-
Organisms
Family
Baetidae
Ceratopogonidae
Tendipedidae
Simuliidae
Unknown
Unknown
Unknown
Limnephilidae
Tendipedidae
Simuliidae
Unknown
_
-
-
State
Nymph
Larvae
Pupae
Larvae
Larvae
Pupae
Unknown
Unknown
Unknown
Pupae
Larvae
Larvae
Unknown
_
-
-
Number
14
1
14
83
455
365
31
2
1
5
29
112
22
0
0
0
Remarks
Filamentous greet
algae and diatoms
on rocks and gravel .
Bottom sediments had
some sand and fine,
soft silt.
Diatoms.
Bottom sediments
of small gravel .
Sand and fine soft
silt.
Very silty. Fine
sand and detritus.
cr>
10
-------
TABLE 2A
FISH CREEK BIOLOGICAL DATA
Date
Station (1968) Sampler Common Name
1 7-26 Surber Mayflies
Caddisflies
True Flies
Miscellaneous
Flatworm
8-2 Surber Stoneflies
True Flies
Miscellaneous
Nematoda
Ekman Trye Flies
Miscellaneous
Nematoda
Water Bears
8-28 Surber Stoneflies
Mayflies
Organisms
Family
Baetidae
Limnephilidae
Tendipedidae
Simuliidae
Empididae
Unknown
Nemouridae
Tendipedidae
Simuliidae
Unknown
Empididae
Tendipedidae
Unknown
Unknown
Perlodidae
Nemouridae
Heptageniidae
State
Nymph
Larvae
Larvae
Larvae
Pupae
Pupae
Unknown
Nymph
Larvae
Pupae
Unknown
Larvae
Larvae
Unknown
Unknown
Nymph
Nymph
Nymph
Number Remarks
3
1
4
2
3
1
1
1
7
1
4
2
24
4
1
23
10
2
-------
TABLE 2A (CONT.)
FISH CREEK BIOLOGICAL DATA
mtr
Station (1968) Sampler Common Name
Mayf 1 i es
1 8-28 Caddisflies
True Flies
Miscellaneous
Oligochaeta
Mites
Nematoda
Flatworm
2 7-26 Surber True Flies
8-2 Surber True* Flies
Ekman True Flies
Miscellaneous
Oligochaeta
8-28 Dipnet
Surber
Organisms
Family State
Baetidae Nymph
Limnephilidae Larvae
Lepidostomatidae Larvae
Tendipedidae Larvae
Empididae Larvae
Ceratopogonidae Larvae
Psychodidae Larvae
Tipulidae Larvae
Unknown Unknown
Unknown Unknown
Unknown Unknown
Unknown Unknown
Tendipedidae Larvae
Tendipedidae Larvae
Ceratopogonidae Larvae
Tendipedidae Larvae
Unknown Unknown
-
— ^f
Number Remarks
9
2
1
139
23
2
4
3
16
2
1
1
1
6
1
3
1
0
0
-------
TABLE 2A (CONT.)
FISH CREEK BIOLOGICAL DATA
Hatn
Uakc
Station (1968) Sampler Common Name
3 8-2 Ekman True Flies
Surber Stoneflies
Caddisflies
True Flies
Miscellaneous
Oligochaeta
Nematoda
4 8-2 Ekman True Flies
Miscellaneous
Nematoda
Surber True Flies
Mayf 1 i es
5 8-2 Surber Mayflies
True Flies
Organisms
Family
Tendipedidae
Nemouridae
Limnephilidae
Tendipedidae
Empididae
Tipulidae
Dolichopodidae
Unknown
Unknown
Tendipedidae
Tipulidae
Unknown
Tendipedidae
Empididae
Heptageniidae
Heptageniidae
Tendipedidae
Empididae
Stage
Larvae
Nymph
Nymph
Larvae
Pupae
Unknown
Pupae
Unknown
Unknown
Unknown
Larvae
Larvae
Unknown
Larvae
Pupae
Unknown
Nymph
Nymph
Larvae
Pupae
Unknown
Number Remarks
9
1
1
86
8
2
1
1
2
1
275
8
3
89
10
1
1
19 Not representat
17 of benthos
1
1
ro
-------
TABLE 2 A (CONT.)
FISH CREEK BIOLOGICAL DATA
Date
Station- (1968) Sampler Common Name
Miscellaneous
Oligochaeta
6 8-2 Ekman True Flies
Miscellaneous
Nematoda
7 7-26 Surber Stoneflies
Mayflies
True Flies
Miscellaneous
Oligochaeta
8-28 Dip Net Stoneflies
Mayflies
Caddisflies
True Flies
Organisms
Family
Unknown
Tendipedidae
Unknown
Nemouridae
Perlodidae
Baetidae
Heptageniidae
Tendipedidae
Simuliidae
Unknown
Nemouridae
Perlodidae
Baetidae
Heptageniidae
Limnephilidae
Tendipedidae
Stage
Unknown
Larvae
Unknown
Nymph
Nymph
Nymph
Nymph
Larvae
Pupae
Larvae
Pupae
Unknown
Nymph
Nymph
Nymph
Nymph
Pupae
Larvae
Pupae
Number Remarks
2
2 Benthos not
representative
1
9
2
8
46
5
1
44
1
1
30
1
30
1
7
90
1
CO
-------
TABLE 2 A (CONT.)
FISH CREEK BIOLOGICAL DATA
n^to Organisms
Station (1968) Sampler Common Name
Miscellaneous
Oligochaeta
8 8-2 Ekman True Flies
Miscellaneous
Nematoda
Mite
Surber True Flies
Stoneflies
Family
Tipulidae
Empididae
Psychodidae
Unknown
Tendipedidae
Simuliidae
Empididae
Unknown
Unknown
Tendipedidae
Simuliidae
Empididae
Nemouridae
Stage
Larvae
Larvae
Larvae
Unknown
Larvae
Pupae
Unknown
Unknown
Unknown
Larvae
Pupae
Unknown
Nymph
Number Remarks
1
2
1
8
1
1
1
1
1
22
1
3
1
Miscellaneous
Nematoda
Unknown
Unknown
-------
TABLE 3A
LIVENGOOD CREEK BIOLOGICAL DATA
Date
Station (1968) Sampler Common Name
1 7-29 Surber Stoneflies
Mayf 1 i es
Caddisflies
True Flies
Miscellaneous
Oligochaeta
3 7-29 Surber True Flies
4 7-29 Surber Mayflies
True Flies
Miscellaneous
Oligochaeta
Mite
Organisms
Fami ly
Nemouridae
Baetidae
Limnephilidae
Tendipedidae
Simuliidae
Tipulidae
Unknown
Tendipedidae
Baetidae
Tendipedidae
Simuliidae
Unknown
Unknown
Stage
Nymph
Nymph
Larvae
Larvae
Larvae
Pupae
Pupae
Unknown
Larvae
Nymph
Larvae
Larvae
Unknown
Unknown
*
Number Remarks
7
35
1
25
78
21
1
27
10
1
3
2
1
1
tn
-------
TABLE 4A
OTTER CREEK BIOLOGICAL DATA
Date
Station (1968) Sampler Common Name
1 8-12 Ekman. True Flies
Miscellaneous
Oligochaeta
2 8-12 Surber Stoneflies
Mayflies
Caddisflies
True Flies
Miscellaneous
Fish
4 8-12 Surber Stoneflies
Mayflies
Caddisflies
True Flies
Beet! e
Organisms
Family
Tendipedidae
Unknown
Perlodidae
Baetidae
Heptageniidae
Limnephilidae
Simuliidae
Tipulidae
Cottidae
State
Larvae
Unknown
Nymph
Nymph
Nymph
Larvae
Larvae
Larvae
Unknown
Perlodidae Nymph
Heptageniidae Nymph
Baetidae Nymph
Limnephilidae Larvae
Lepidostomatidae Larvae
Tendipedidae
Unknown
Larvae
Pupae
Number Remarks
27
2
5
26
37
12
3
3
1
4
23
5
26
13
11
1
-------
TABLE 5 A
INMACHUK RIVER BIOLOGICAL DATA
Date
Station (1968) Sampler Common Name
1 8-13
4 8-13
Ekman
Surber
Surber
Ekman
Surber
Surber
Organisms
Family Stage
-
-
Number
0
0
0
0
0
0
Remarks
-------
TABLE 6A
H06ATZA RIVER BIOLOGICAL DATA
Date
Station (1968) Sampler Common Name
1 8-9 Surber Stoneflies
Mayflies
Caddisflies
True Flies
Miscellaneous
Nematoda
Ekman Mayflies
True Flies
3 8-9 Ekman;
Ekman
4 8-9 Surber Stoneflies
Ekman Mayflies
True Flies
Organisms
Family State
Nemouridae Nymph
Heptageniidae Nymph
Baetidae Nymph
Limnephilidae Larvae
Tendipedidae Larvae
Simuliidae Larvae
Ceratopogonidae Larvae
Unknown Unknown
Heptageni i dae Nymph
Tendipedidae Larvae
Tipulidae Larvae
Ceratopogonidae Larvae
_ _
-
Nemouridae Nymph
Baetidae Nymph
Heptageniidae Nymph
Tendipedidae Larvae
Pupae
Simuliidae Larvae
Empididae Larvae
Number Remarks
1
12
4
1
42
4
1
1
1
1
1
1
0
0
13
25
48
81
2
1
1
00
-------
TABLE 6A (CONT.)
H06ATZA RIVER BIOLOGICAL DATA
Date
Station (1968) Sampler
5 8-9 Ekman
Common Name
Miscellaneous
Mite
Nematoda
Oligochaeta
Scuds
True Flies
Miscellaneous
Nematoda
Organisms
Family State
Unknown Unknown
Unknown Unknown
Unknown Unknown
Talitridae Adult
Tendipedidae Larvae
Ceratopogonidae Larvae
Unknown Unknown
Number
1
1
13
1
1
1
1
Remarks
Sample not
representative
i.e. river too
biq.
iO
-------
TABLE 7A
PORCUPINE CREEK BIOLOGICAL DATA
Date
Station (1968) Sampler Common Name
1 8-21 Surber Stoneflies
Mayflies
True Flies
Miscellaneous
Flatworms
Watermi tes
Dipnet Stoneflies
Mayflies
Caddisflies
True Flies
Organisms
Fami ly Stage
Nemouridae Nymph
Baetidae Nymph
Tendipedidae Larvae
Empididae Pupae
Unknown Unknown
Unknown Unknown
Nemouridae Nymph
Perlodidae Nymph
Chloroperlidae Nymph
Baetidae Nymph
Heptaqeniidae Nymph
Limnephilidae Larvae
Tendipedidae Larvae
Pupae
Simuliidae Larvae
Empididae Pupae
Number
5
6
2
3
3
2
20
3
4
23
A
2
71
1
1
18
Remarks
Clean bottom
3 8-21 Surber
4 8-21 Surber
Miscellaneous
Nematoda
Watermites
Springtails
Mayflies
Unknown
Unknown
Unknown
Unknown
Unknown Unknown
Heptageniidae Nymph
4
5
2
1
Water turbid
Mine Sluicing
Sample not
representative
00
o
-------
TABLE 7A (CONT.)
PORCUPINE CREEK BIOLOGICAL DATA
Date
Station (1968) Sampler
Common Name
amsms
Family
Stage
Number
Remarks
8-21 Surber
Dipnet
True Flies
Mayflies
Caddisflies
True Flies
Tendipedidae Larvae
Heptageniidae Nymph
Lepidostomatidae Nymph
Tendipididae Larvae
Empididae Larvae
2
1
Samples not
representative
Stream too large
-------
82
APPENDIX B
DEFINITION OF TERMS
-------
83
DEFINITION OF TERMS
Alluvium Stream deposits of comparatively recent time.
Benthos Bottom dwelling organisms.
Dissolved Oxygen . . . The amount of oxygen dissolved in water. It
is generally referred to as D.O. and is ex-
pressed in milligrams per liter (mg/1).
Hydraulic Giant . . . The large nozzle or water cannon used in
hydraulic stripping and mining.
Hydraulic Stripping . The removal of the earth material that over-
lies an ore zone by a powerful jet of water.
Loess A homogeneous, non-stratified deposit of wind-
blown material consisting predominantly of
silt.
Sluicing The washing of gold-bearing materials through
long boxes or troughs which are provided
with riffles for arresting the gold.
Turbidity The cloudiness of water caused by the presence
of suspended matter. These particles cause
light to be scattered and absorbed rather
than transmitted in straight lines. It is
measured in Jackson Turbidity Units (JTU).
------- |