r
FEDERAL WATER POLLUTION CONTROL ADMINISTRATION
    NORM! REGION. ALASKA WATER LABORATORY
       EFFECTS OF PLACER
       MINING  ON WATER
       QUALITY IN ALASKA
            February 1969

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           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

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          >o/0
^
r/>7*>
         Cr.
                         noilings
         FISH CREEK MINE
                                                      N
                                            0   I
                    •^Sampling Station
            Figure 7.  Fish  Creek Area

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                                                                 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.

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                                           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

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                                        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

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                                            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

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                                                                   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.

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                           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.

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LIVENGOOD MINE
Tailings
      'LIVENGOOD
               A Sampling Station
                                         MILES
          Figure 8.  Livengood Creek Area

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                                  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

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                                                                  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.

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                                                                  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.

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     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.

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                        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.

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                                                                  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

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FLAT
                                    ^Sampling Station
                                                                  MILES
                           Figure 9.   Otter Creek Area

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              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

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                                                                  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.

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                                                                  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.

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                                                                  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

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                                                                  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

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                        /PEERING
                          10.5 MILES
                    I
              Tailingsr"
INMACHUK
   MINE
                  Sampling Station

                     MILES
                        I
       Figure 10.   Inmachuk River Area

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                                            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

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                                                                  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.

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                                                                  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.

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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.

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                                                                  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

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                                 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.

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                                                                  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.

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                                                                   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.

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            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

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                                                                  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.

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                                                                   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.

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                                                                     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

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      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

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         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

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             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

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                                        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

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                                           82
    APPENDIX B



DEFINITION OF TERMS

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                                                                   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).

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