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Tungsten Deposits in 

the Fairbanks District 

Alaska

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T GEOLOGICAL SURVEY BULLETIN 1024-1

Tungsten Deposits in 

the Fairbanks District 

Alaska

By F. M. BYERS, JR.

MINERAL RESqURGES OF ALASKA

GEOLOGICAL SURVEY BULLETIN 1024-1

Description of the scheelite deposits 

in relation to geologic features, with 

-suggestions for further exploration

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1957
UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED A. SEATON, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director

For sale by the Superintendent of Documents, U. S. Government Printing Office 

Washington 25, D. C. - Price $1 (paper cover)
CONTENTS

Page

Abstract_________________________________________________ 179

Introduction._____________________________________________________ 180

Location and accessibility._____________________________________ 180

Topography and drainage____________________________________ 180

Climate and vegetation______________________________________ 182

History of the area__________________________________________ 183

Field work and acknowledgments______________________________ 184

Geology___________________________________________ 184

Regional setting.____________________________________________ 184

Rocks_______________________________________________ 185

Metamorphic rocks_--___---___--_-___--______-__-_-_----_- 185

Igneous rocks-____________________________________________ 185

Structure___________________________________ 186

Description of deposits..___________________________________ 187

Gilmore Dome area_-__-____-___-______-_--___-__-_-_--_-__-__- 188

Stepovichlode..._._____________________________ 189>

Rocks_______-__-__-__-_-____-_-_______--_-_--_-._ 190

Structure...___________________________.._. 192

Ground-water leaching of scheelite_____________________ 192

Distribution of scheelite-----______-_----------__-_---_- 194

Localization of ore shoots_____________________________ 196

Grade.--......--.-.._-__-._..._-_---_------_---____- 197

Colbert lode. . ________ _ _____. ___ _ ________ 199

Yellow Pup prospect_______________________________________ 200

Schubert prospect.________________________________________ 201

Steele Creek-First Chance Creek area_____-___-_-___-__--_----_ 201

Spruce Hen prospect___________________________.___________ 202

Blossom prospect____-__-______.___________________________ 203

Tanana prospect__________________________________________ 204

Tungsten Hill prospect.._____________-__-______--_--_----_- 205

Columbia prospect___.____________________-._-__---__ -_ 205

Pedro Dome area____________________________________________ 206

Wackwitz mine__________________________________________ 206

Mizpah mine____-_-______________--____-_______--__-,- 208

Cleary Hill mine..._________________________ 208

Leslie prospect-___--__--___-__-_____--__-_-_-__-_---__--_- 209

Egan prospect___________.__-________.____-____-_-_--___ 210

Minor occurrences of scheelite_____________________________ 210

Placer scheelite___-__.__-_______________ ____.__._ 210

Areas favorable for prospecting____________________________________ 211

Literature cited__-____-_._____--______.______--__-_--__-__----_._- 212

_________-____._-.__________________________-___________-_ 215

in
IV CONTENTS

ILLUSTRATIONS

[Plates are in pocket]

PLATE 23. Map showing intrusive rocks and scheelite lodes northeast of 

Fairbanks, Alaska.

24. Geologic map showing scheelite deposits, Gilmore Dome, 

Fairbanks district.

25. Geologic map and sections of Stepovich mine.

26. Geologic maps of bulldozer trenches 4-24 on Stepovich lode, 

Gilmore Dome.

27. Geologic maps of bulldozer trenches on Colbert lode, Gilmore 

Dome.

28. Scheelite prospects between Steele Creek and First Chance

Creek, Fairbanks district.

Page

FIGURE 24. Index map showing area of tungsten-bearing rocks in the

Fairbanks district. ____________._>_____________---_-___ 181
MINERAL RESOURCES OF ALASKA

TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT,

ALASKA

By F. M. BYERS, Jr.

ABSTRACT

Although principally a gold-mining camp since 1902, the Fairbanks district, 

Alaska, has been a tungsten-producing district at intervals since 1916. The 

tungsten deposits discussed in the present report are 10 to 20 miles northeast of 

Fairbanks within the Yukon-Tanana upland. The tungsten occurs as the mineral 

scheelite (calcium tungstate) in thin beds and lenses of metamorphosed limestone 

and calcareous mica schist, in quartz pegmatites, and in gold quartz veins.

The limestone is a very minor part of an early Precambrian sequence of quartzmica schist, quartzite, and associated intrusives. This sequence was intruded by 

porphyritic granite of Mesozoic age, which is probably the source of the metalliferous deposits. Tertiary granodiorite is also exposed in the district.

The scheelite deposits are segregated geographically in three areas: the Gilmore 

Dome area and Steele Creek-First Chance Creek area in the southern part of the 

district and the Pedro Dome area in the north-central part. The Stepovich mine 

in the Gilmore Dome area contains the largest known scheelite deposit in the 

district. During the periods 1915-18 and 1942-44 about 4,000 units (20 pounds 

to a short ton unit) of WOg as scheelite ore and concentrates have been produced 

from 3 inclined shafts on the Stepovich lode.

The Stepovich lode is a series of silicated limestone lenses, which were probably 

derived from a continuous bed of limestone a few feet thick. During regional 

metamorphism the limestone was squeezed into "rolls" and discontinuous bodies 

and was largely replaced by silicate minerals, quartz, and scheelite. The richest 

ore shoots in the lode occur at intersections of quartz pegmatite dikes with the 

limestone. A secondary factor in the localization of the pegmatite dikes and the 

ore shoots was probably an amphibolite mass exposed in the Stepovich mine 

along the footwall of the lode.

The Colbert property and the Yellow Pup prospect on the easterly extension 

of the Colbert lode are on a lode similar and parallel to the Stepovich lode and 

about 1,000 feet to the south. The Colbert lode contains more abundant silicate 

minerals, especially garnet, but scheelite is much less abundant than in the 

Stepovich lode. The Schubert prospect contains a minor occurrence of scheelite 

in metamorphosed limestone at the contact of a large body of porphyritic granite.

The Spruce Hen, Blossom, Tanana, Tungsten Hill, and Columbia prospects in 

the Steele Creek-First Chance Creek area are only in the prospect stage of de179
180 MINERAL RESOURCES OF ALASKA

velopment. Of these, the Spruce Hen is the only one with a single well-defined 

lode of scheelite-bearing silicated limestone. The others are of the quartz pegmatite stringer type and have not been sufficiently worked to expose any amount of 

ore.

Gold veins containing scheelite are predominant in the Pedro Dome area, 

though scheelite has been found in metamorphosed limestone and pegmatite. 

The Wackwitz and Mizpah gold quartz mines have produced small tonnages of 

scheelite concentrates as a byproduct of gold production. Scheelite has also 

been found in the Cleary Hill, Johnson, Rainbow, and Tolovana gold mines, and 

probably occurs in other gold mines in the area. The Leslie prospect has exposed 

a scheelite-bearing lode of metamorphosed limestone. The Egan prospect was 

staked on a minor, but interesting, occurrence of scheelite in a pegmatite of 

porphyritic granite.

Scheelite as a placer mineral has been found in the gravels of most of the 

streams of the Fairbanks district; it is especially abundant in streams draining 

the lode areas.

The most favorable areas for scheelite prospecting are in country rock on the 

hanging-wall side of the smaller masses of porphyritic granite, as these granite 

masses, which conform to the regional dip, would normally underlie these areas. 

Pegmatites from the granite in these localities would thereby have had a more 

favorable chance of intersection with limestone beds that now are at or near the 

present surface. In an area of extensive overburden, as in the Fairbanks district, 

systematic prospecting with a small pesthole auger should be undertaken.

INTRODUCTION

LOCATION AND ACCESSIBILITY

Scheelite (calcium tungstate) has been found at many localities in 

the lodes and placers of the Fairbanks district, Alaska. These deposits are from 10 to 20 miles northeast of Fairbanks (fig. 24). The 

Pedro Dome gold-tungsten lodes occupy the northern part of the 

scheelite-bearing area; the Gilmore Dome lodes and those of the 

Steele Creek-First Chance Creek area lie along the southern part. 

The geographic relationships are shown on plate 23.

All the tungsten deposits are accessible by truck during the summer 

months by secondary roads some in poor condition which connect 

with the Steese Highway, a graded road (pi. 23). The distance to 

Fairbanks from the point where the Steese Highway leaves the map 

on the southern border is 7% miles. Automobiles, trucks, and bulldozers are available for purchase or hire in Fairbanks.

Fairbanks, with a population of over 5,000, can be reached from 

Seattle, Wash., by at least three different routes involving land, sea, and 

air transportation. The oldest established sea-land route is via boat 

from Seattle, Wash., to Seward, Alaska, and thence to Fairbanks 

via the Alaska Railroad. The rail distance from Seward to Fairbanks 

is 468 miles.
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 181

>Qo_______172"

148°

FIGTJEE 24. Index map showing area of tungsten-bearing rocks in the Fairbanks district, Alaska.

TOPOGRAPHY AND DRAINAGE

The area of the tungsten deposits is characterized by gently rolling 

mature topography having an average relief of about 1,000 feet. 

The area is typical of the upland lying between the Yukon and Tanana 

Rivers.

The entire area is within the drainage basin of the Tanana River, 

which lies about 10 miles south of the southern border of the tungsten 

area as shown on plate 23. The main streams, the Chatanika River 

in the northwestern part and Goldstream Creek in the southwestern 

part, flow in broad flat-bottomed valleys whose floors range from 600 

to 800 feet in altitude within the tungsten-bearing area. These 

streams flow westward to the Tanana River. Steele and Smallwood 

Creeks in the southern part of the area flow southward, and Fairbanks 

and Fish Creeks in the eastern part of the area flow eastward. The 

head of Goldstream Creek is at the confluence of Pedro and Gilmore 

Creeks.

The ridges between the headwaters of the streams are rounded 

divides at altitudes ranging from about 1,800 to about 2,200 feet. 

In places, chiefly where two or more ridges intersect, low rounded
182 MINERAL RESOURCES OF ALASKA

domes rise as high as 2,600 feet. Two of these domes Pedro Dome 

in the north-central part of the area and Gilmore Dome in the 

southern part of the area (pi. 23) are about 2,600 feet and 2,400 

feet in altitude, respectively, and are convenient topographic features 

for locating the tungsten-bearing lodes in the vicinity.

CLIMATE AND VEGETATION

The climate of the Fairbanks district is subarctic with short, warm 

summers characterized by 16 to 20 hours of sunlight and long, cold 

winters with temperatures reaching 60°F. A summary of climatic 

data from the Weather Bureau station at Fairbanks is given in the 

table below.

Climatological data at the Fairbanks Weather Bureau station 1900 48

Month

February ___ ______ __ _ ______ _ _

March _ ___ ___ ______ _ _ ______ __

April- ____ __ __ ________ ________ ____

May__ _____ _ __________

June_______ _ __ _____ __ _ _ __ _

July __ _____ __ _ __ _____ ___

September __ __ _ _____

October __ __ ____ ______

November. __ _______ _______

December. _ ________ ____

Mean 

temperature (°F)

-11. 2

-1. 6

9. 5

29. 2

46.9

58. 3

60. 1

54. 8

43. 6

26. 7

4. 1

-7. 1

26. 1

Average 

precipitation 

(inches)

0.97

.49

. 70

. 28

.57

1. 30

1. 92

2. 10

1. 31

. 85

.72

. 63

11. 84

Average 

snowfall 

(inches)

11. 7

7.2

8. 1

2. 7

. 4

C1 )

.0'

. i

. 7

6. 5

7.4

8.7

53. 9-

1 Less than 0.05 inch.

The Fairbanks Weather Bureau station is located at a relatively low 

altitude near the lowest part of the Tanana Valley, and hence the 

summary in the table may be misleading to anyone contemplating 

work in the hilly country northeast of Fairbanks. The annual range 

of temperature at the higher average altitude of the tungsten area is 

somewhat lower than in Fairbanks. Unofficial temperatures recorded 

at several mining camps in the tungsten area are generally 5° to 10°F 

cooler in summer than the temperature recorded at the same time in 

Fairbanks and are often as much as 30°F warmer in winter, because 

of the tendency of the cooler air to settle into the valleys on still days, 

which are prevalent in winter. Total precipitation is greater in the 

tungsten area than in Fairbanks. A somewhat greater annual pre-
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 183

cipitation occurs on the summit of Gilmore Dome, where the richest 

tungsten deposits are found, than at Fairbanks. The snowfall in 

Fairbanks in early November of 1943 was 2 inches whereas on Gilmore 

Dome it was 6 inches. Frequently during the winter the Steese Highway becomes temporarily blocked with snowdrifts in the vicinity of 

the pass (2,200 feet) between Pedro and Cleary Creeks (pi. 23).

The ground in the bottoms of stream valleys is permanently frozen, 

in some places to a depth of about 300 feet. The permanently frozen 

ground decreases markedly upslope, and the ridges are free of permafrost (Troy L. P6w6, 1951, oral communication). Ice-filled cavities 

and fissures, however, are frequently encountered in lode mining 

operations. The streams generally freeze around the middle of October 

and do not thaw until early May. At Fairbanks the breakup of river 

ice in the Tanana River generally occurs during the first week in May, 

but it may come nearly 2 weeks before or after this date.

A heavy mantle of vegetation covers the area and includes coniferous 

and deciduous trees, flowering plants, ferns, and mosses. Below an 

altitude of about 2,000 feet the mosses and ferns form a thick mat so 

that traversing becomes difficult. This vegetal covering is thin or 

lacking in heavily forested patches. The common trees are white 

spruce, cottonwood, alder, quaking aspen, and white birch. The 

white spruce is largest and most abundant, with trunks as much as 2 

feet in diameter. In the Fairbanks tungsten area the timberline ranges 

from 2,000 to 2,300 feet in altitude, and for about 200 feet below 

timberline the trees are stunted.

HISTORY OF THE ABBA

The Fairbanks district became established as a mining area with 

the discovery of placer gold in 1902. Exploitation of several tungsten 

deposits in the Fairbanks district began in 1915 under the stimulus 

of an increased average price of $24.59 a unit for concentrates contaming 60 percent or more WO3 . During the years 1915-18, 10 tons 

of scheelite concentrates containing about 65 percent of W03 and 300 

tons of hand-sorted ore containing 8 percent of WO3 were produced 

from the Gilmore Dome area (Thorne and others, 1948, p. 8). After 

1918 the prices dropped to less than $12.50 a unit and all development work ceased.

In 1931 minor underground work was done on Gilmore Dome 

(Hill, 1933, p. 157), but no ore was produced. The Cleary Hill Mines 

Co. began operations at Gilmore Dome in 1942 and continued mining 

during 1943 and the early part of 1944. As a result of these mining 

operations during 1942-44, Cleary Hill Mines produced 2,196 units 

of WO3 , largely as concentrates containing over 64 percent of

406511 57 2
184 MINERAL RESOURCES OF ALASKA

FIELD WORK AND ACKNOWLEDGMENTS

During the early period of tungsten production, from 1915 through 

1918, the Geological Survey examined the tungsten deposits at 

Gilmore Dome and in the Steele Creek-First Chance Creek area. 

(See Brooks and others, 1916, p. 61-62; Mertie, 1917, p. 418-424; 

and Chapin and Harrington, 1919, p. 324-327.) In August and 

September 1942, a Survey party consisting of J. B. Mertie, Jr., W. C. 

Overstreet, and P. L. Killeen investigated the tungsten and antimony 

deposits of the Fairbanks district. From June through September 

1942, and early in 1943, H. R. Joesting and Eskil Anderson, of the 

Alaska Territorial Department of Mines, conducted geologic and 

magnetometer surveys of the Gilmore Dome tungsten area. From 

July to the middle of November 1943, the Federal Bureau of Mines 

tested the two tungsten-bearing lodes at Gilmore Dome by surface 

trenching with bulldozer and by channel sampling. During that 

time the writer prepared maps of the trenches and also of the recent 

mine workings of the Cleary Hill Mines Co. on Gilmore Dome, and 

continued tungsten investigations elsewhere in the district. This 

field work was done under the general supervision of George O. Gates. 

During the summer of 1945, several days were spent on Gilmore Dome 

mapping workings of the Cleary Hill Mines Co., which were completed after the 1943 field season.

The report covering the U. S. Bureau of Mines development work 

on the Gilmore Dome tungsten lodes was released in June 1948, as 

Report of Investigations 4174 (Thorne and others, 1948).

The present report is based in part upon an earlier report, having 

the same title, that was prepared for the war agencies in 1943 by 

J. B. Mertie, Jr., and W. C. Overstreet.

Mr. Ralph E. Wyer, manager of the Cleary Hill Mines Co., furnished 

data on the operation of the Stepovich mine, and Mr. L. C. Doheny, 

supervising engineer of the Reconstruction Finance Corporation , 

furnished office facilities in Fairbanks. Mr. Louis D. Colbert and 

Mr. Elmer Stohl contributed information on the Colbert lode and 

Yellow Pup properties, respectively.

GEOLOGY

REGIONAL SETTING

The geologic features of the Fairbanks district have been described 

by Prindle, Katz, and Smith (1913).

The Fairbanks area of tungsten-bearing rocks (pi. 23) is entirely 

within a much larger area of highly metamorphosed Precambrian 

rocks designated by earlier workers as the Birch Creek schist. According to Mertie (1937, p. 46-59), the Birch Creek schist forms the 

bedrock surface of about one-fifth of the country between the Yukon
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 185

and Tanana Rivers and is regarded as early Precambrian. No older 

rocks are known in this part of Alaska. Within the area of Birch 

Creek schist are smaller areas of several varieties of intrusive granitic 

rocks to which'Mertie (1937, p. 215-216) assigned Mesozoic and 

Tertiary ages. Bordering some of these intrusive rocks are contactmetamorphic zones of country rock in which scheelite deposits are 

commonly found. Gold quartz veins, several of which are known to 

contain scheelite, are commonly found in the country rock farther 

from the igneous border. All the mineral deposits of the Fairbanks 

district are believed by Mertie (1937, p. 241-242) to be derived from 

the intrusive rocks of Mesozoic age.

BOCKS

METAMORPHIC ROCKS

The Birch Creek schist in the tungsten area consists largely of 

metamorphosed sedimentary rocks, of which the most common are 

quartz-mica schist, schistose quartzite, and quartzite,, The quartzmica schist contains quartz, biotite, and muscovite and minor amounts 

of apatite, magnetite, albite, and other accessory minerals. Other 

metamorphic rocks that form a minor part of the country rock are 

hornblende schist, amphibolite, gneiss, carbonaceous schist, and 

crystalline limestone.

Lenticular beds of crystalline limestone averaging a few feet in 

thickness crop out in two general zones. Each zone is composed of 

small discontinuous bodies, which originally may have been several 

continuous beds. One of these zones lies along the north side of the 

Pedro Dome belt,; the other, which is much less conspicuous, is along 

the north side of the porphyritic granite in the Gilmore mineralized 

belt,

IGNEOUS ROCKS

The metamorphic rocks are cut by granodiorite, porphyritic 

granite, and altered porphyritic dike rocks of dioritic and granitic 

composition. On plate 23 each of these intrusive rocks has been 

shown separately.

The granodiorite at Pedro Dome is an irregular elongate body 

extending from the headwaters of Dome Creek easterly for 3K miles 

to a point beyond Pedro Dome. The width averages about 0.2 mile 

at its western end and reaches a maximum width of 0.6 mile at its 

eastern end; the total area is about \% square miles. A smaller area 

of the same intrusive is about 1 mile southeast of Pedro Dome.

According to Prindle, Katz, and Smith (1913, p. 68), the granodiorite "ranges from dark gray to light gray in color, from medium 

to fine in grain * * * the minerals observed in different varieties are 

quartz, soda-lime feldspar, alkali feldspar, biotite, hornblende,
186 MINERAL RESOURCES OF ALASKA

pyroxene, titanite, ilmenite and other iron minerals, zircon and 

apatite."

The porphyritic granite is exposed in the Pedro Dome gold belt 

and in the Gilmore mineralized belt and is considered by Mertie 

(1937, p. 241-243) to have given rise to the gold and tungsten 

mineralization. A small mass of porphyritic granite is exposed 1 mile 

southeast of Pedro Dome. The principal body of the porphyritic 

granite, however, lies in the Gilmore mineralized belt and extends 

easterly from the head of Engineer Creek for about 1% miles to the 

head of Pearl Creek. Over most of this distance the width varies 

from % to 1% miles, and the total area is about 1% square miles. The 

main porphyritic granite mass is markedly irregular at its western 

end, terminating in several sill-like apophyses. An outlying cupola 

of the same mass lies about a mile north of its eastern end. The rock 

is rather coarse grained with an average grain size of one-fourth inch. 

Grayish, clear quartz grains are embedded in white feldspar. The 

minerals of the porphyritic granite are quartz, microcline, oligoclase, 

muscovite, biotite, zircon, apatite, sphene, and magnetite.

The altered granitic intrusives are porphyritic rocks, largely dikes. 

They are white friable rocks that are stained yellowish brown with 

ferruginous matter. Prindle, Katz, and Smith (1913, p. 73) regard 

these dikes as offshoots from the mass of porphyritic granite, which 

have been subsequently altered by hydro thermal emanations from 

the porphyritic granite itself.

Quartz pegmatite dikes ranging from a fraction of an inch to about 

1 foot in thickness cut the Birch Creek schist north of the main stock 

of porphyritic granite and are clearly derived from the granite. 

Many of the same minerals present in the pegmatite dikes are in the 

granite; namely, quartz, microcline, oligoclase, muscovite, zircon, 

apatite, sphene, and magnetite. Quartz is predominant and ranges 

from 50 to 99 percent of the rock by volume. Thus, the pegmatites 

containing the higher quartz content approach true quartz veins in 

composition. Skarn minerals, such as garnet, zoisite, and others, are 

found in association with minerals of the pegmatite close to the 

intersections of the pegmatites with beds of crystalline limestone. 

Pegmatites have not been found associated with the small stocks of 

porphyritic granite in the northern part of the area but are probably 

present. The quartz pegmatite dikes in general strike northwestward 

and dip steeply northeast.

STRUCTURE

No detailed mapping has been done in the Fairbanks district on 

the structure of the Birch Creek schist and its associated intrusions. 

Outcrops of the schist are relatively rare, and most of them appear
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 187

to be slumped. The generalized statements of Prindle, Katz, and 

Smith (1913, p. 75-76) are the most recent on the general structure 

of the Birch Creek schist within the Fairbanks district.

The Birch Creek schist is believed by the earlier workers to have 

been tightly folded. The bedding is in most places nearly parallel to 

the schistosity. The regional strike is N. 60°-80° E. In the Gilmore 

mineralized belt, comprising the Gilmore Dome and Steele Creek-First 

Chance Creek areas, the schist has an average dip of about 35° N., 

but dips, ranging from horizontal to 70° N., prevail over distances 

of a few tens of feet. In a few places, owing to minor drag folding, 

reversals of dip occur. Minor, discontinuous, steeply dipping faults, 

striking northerly, cut the schistosity and have displacements ranging 

from a few feet to several tens of feet. The structure of the Pedro 

Dome gold-scheelite mineralized belt is extremely complex and has 

not yet been deciphered. The general strike of the schist is about 

N. 75° E. with low dips both northward and southward. The structure is further complicated by an intricate network of faults and veins. 

According to James M. Hill (1933, p. 84), who examined many goldlode properties in the vicinity, the Pedro Dome mineralized belt is 

apparently on the axis of a low anticlinal fold. This deduction would 

appear contradictory to the general idea of tight folding held by the 

earlier workers, but these two opposing structural concepts cannot 

be resolved without further field work.

The intrusive rocks are roughly concordant with the enclosing 

Birch Creek schist, as the contact parallels the schistosity. The eastnortheasterly orientation of the bedrock surfaces of nearly all the 

intrusive rocks shown on plate 23 suggests that the dominant structural control in their emplacement was the foliation of the Birch 

Creek schist.

DESCRIPTION OF DEPOSITS

Lode tungsten deposits, containing scheelite as the tungsten mineral, 

occur in three main areas: the Gilmore Dome area, the ridge between 

Steele Creek and First Chance Creek, designated in this report as the 

Steele Creek-First Chance Creek area, and the Pedro Dome area 

(pi. 23). Essentially all tungsten production has come from the Gilmore Dome area. The Gilmore Dome and Steele Creek-First Chance 

Creek deposits lie on the north side of the elongate stock of porphyritie 

granite, and their position is probably determined by a belt of calcareous schist containing thin limestone beds. These limestones are 

replaced by scheelite and skarn minerals, such as diopside, green 

hornblende, garnet, zoisite, and vesuvianite. The scheelite of the 

Pedro Dome area occurs chiefly as a minor constituent in the gold 

quartz veins and hence is only recoverable as a byproduct of gold 

mining.
188 MINERAL RESOURCES OF ALASKA

The origin and localization of the tungsten appear clearly indicated 

in those deposits studied in detail. The tungsten metallization was 

probably derived from the porphyritic granite, for the pegmatite dikes 

associated with the scheelite deposits contain the same accessory 

minerals that are present in the porphyritic granite. Scheelite occurs 

in the pegmatites near crystalline limestone beds intercalated within 

the schist. The crystalline limestone is host to rich scheelite ore 

shoots at the intersection of the pegmatite dikes or pegmatitic quartz 

veins with the limestone. Scheelite-bearing gold quartz veins are 

notably richer in scheelite at places where calcareous beds in the 

schist are intersected, but the scheelite ore shoots within the gold 

quartz veins are much smaller than the skarn scheelite deposits. In 

places, the calcareous beds adjacent to the gold quartz veins have 

been partly replaced by scheelite to as much as a foot from the vein. 

Thus, the primary control that localized the tungsten deposits is the 

intersection of a mineralized fissure with a calcareous bed. The grade 

and size of the deposits, however, decrease in general with increasing 

distance from the porphyritic granite.

Ground-water leaching of scheelite in the weathered zone seems to 

have occurred in a few places on the upper 10 feet of the Stepovich 

lode and possibly on the Spruce Hen lode (R. M. Chapman, 1952, 

written communication).

Scheelite has been found in the placer concentrates at many places 

in the Fairbanks district: in the Gilmore Dome area in the placers of 

Fish, Pearl, and Gilmore Creeks; in the Steele Creek-First Chance 

Creek area in the gravels of Rose, First Chance, and Goldstream 

Creeks, and undoubtedly in the gravels of Steele and Engineer Creeks; 

and in the Pedro Dome area in the gravels of Fox, Dome, Eldorado, 

Bedrock, Chatham, Cleary, and Fan-banks Creeks. Scheelite also 

occurs in the placer concentrates of Ester Creek about 10 miles west

of Fairbanks.

GILMORE DOME AREA

The Gilmore Dome area is 14 miles northeast of Fan-banks, at the 

eastern end of the main mass of porphyritic granite. The area can 

be reached by either of 2 automobile roads, each about 6 miles in 

length, which join the Steese Highway near the 13-mile and 20-mile 

posts out of Fairbanks (pi. 23). The shorter route from Fairbanks 

branches from the Steese Highway where Gilmore and Pedro Creeks 

join to form Goldstream Creek. The other route was made available 

in 1943 when the Cleary Hill Mines Co. constructed a road 4 miles 

long from Gilmore Dome to the Fish Creek road. This route was 

used during 1943 and 1944 to haul tungsten ore from Gilmore Dome 

to the Cleary Hill Mines mill on Clearj Creek.
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 189

The richest and largest of the known tungsten deposits in the 

Gilmore Dome area is the Stepovich lode, which was discovered by 

Albert Johnson in 1915. Since 1942 several other scheelite deposits 

have been discovered in the area. These are on the Colbert lode and 

the Yellow Pup and Schubert prospects. Plate 24 shows the surface 

development work on these properties by local prospectors and by 

the U. S. Bureau of Mines during 1943.

The Stepovich and Colbert lodes were formed by replacement of 

calcareous layers in the country rock, which consists mainly of quartzmica schist. The lodes and the schist strike about N. 70° E. and dip 

about 35° N. The Stepovich and Colbert lodes lie about 0.6 mile 

and 0.4 mile, respectively, north of the main body of porphyritic 

granite and about 0.7 mile and 0.8 mile south of the outlying cupola 

of the same granite (pi. 23).

The Yellow Pup prospect is on an apparent extension of the Colbert 

lode to the northeast. Scheelite also occurs sporadically outside the 

two main lodes as scattered grams in lenses of silicated schist and in 

pegmatitic quartz veins which transect the schist and the lodes. The 

Schubert prospect, not shown on plate 24, lies to the southwest of the 

Colbert claims and is probably staked on a small lens of scheelitebearing silicated schist.

STEPOVICH LODE

By far the most development work on tungsten properties at 

Gilmore Dome has been on the Stepovich lode. Since the discovery 

of the lode in 1915 about 2,000 feet of underground work has been 

done on the Stepovich property, 1,700 feet of which was on the lode. 

The underground workings of the Stepovich mine are shown on plate 

25. During the period 1915-18, 2 inclined shafts, about 325 feet 

apart on 2 adjoining properties (Mertie, 1917, p. 418-421), were 

driven northward down the dip of the lode at an angle of about 

30° (see pis. 24 and 25). These shafts are now caved. Shortly after 

World War I, Mike Stepovich, Sr., acquired both properties and 

patented 7 claims. A 170-foot adit was driven by Stepovich in 1931, 

but it did not intersect the main lode. From the spring of 1942 to 

the summer of 1944, the Cleary Hill Mines Co. leased the claims held 

by Stepovich. Development work by this company consisted of a 

170-foot inclined shaft midway between the 2 older shafts with drifts 

at about 50 feet and 150 feet down the dip of the lode. These drifts 

are designated in this report as the "50 level" and "150 level" instead 

of the "50-foot level" and the "150-foot level" as originally named, 

because the drifts are considerably less than these depths-below the 

surface on account of the low angle of dip of the lode. An adit was 

driven in 1943 to intersect the east end of the drift on the 150 level
190 MINERAL RESOURCES OF ALASKA

(pi. 25). The mine has been idle since early summer of 1944, when 

the Cleary Hill Mines lease on the Stepovich property was terminated. 

Since the death of Mike Stepovich, Sr., in the latter part of 1944, the 

property has been owned by his widow, Mrs. Vuka Stepovich, and 

his two sons, Mike, Jr., and Michael.

During the years 1915-18, about 10 tons of scheelite concentrates, 

containing about 65 percent of WO3 and 300 tons of sorted ore containing about 8 percent of WO3 were produced, according to Mike 

Stepovich, Sr. (Thorne and others, 1948, p. 8). The crude ore i& 

reported to have contained about 2 percent of recoverable WO3 . 

The World War I production came from the 2 caved shafts to the 

east and west of the Cleary Hill Mines shaft (pi. 25). No data are 

available on the proportions of ore mined from each of these World 

War I workings.

From the early summer of 1942 until May 1944, the Cleary Hill 

Mines Co. produced a total of 2,196 units of WO3 , which came almost 

entirely from the inclined shaft workings near the summit of Gilmore 

Dome. The tungsten production, which comprised ore and middling 

and table concentrates, is summarized in the table below. The ore 

was processed by wet gravity separation on tables at the Cleary Hill 

Mines mill on Cleary Creek. The entire production was sold to the 

Metals Reserve Company, Reconstruction Finance Corporation, 

Washington, D. C.

Tungsten production of the Cleary Hill Mines Co. from the Stepovich lode 

[Data from flies of Metals Reserve Company, Reconstruction Finance Corporation, Washington 25, D.C.|

Year

1942___ _ _______

1943__. _________

1944_____________

1944

Totals. _____

Type

Ore

Concentrates

Concentrates __ ____

Middlings __ __ _ __ _

Ore

Tonnage

60. 084

9. 170

17. 288

11. 869

60. 084

38. 327

Grade 

(percent)

4. 55

68. 39

64.27

15. 56

Units of 

WOs

273

627

1, 111

185

273

1,923

From July to October 1943, the Bureau of Mines dug 24 bulldozer 

trenches on the Stepovich lode to determine the extent and grade of 

the ore. These trenches are shown on plates 25 and 26. Trench 3 

is not shown because it is covered by the dump from the 1943 tunnel.

BOCKS

The chief rock units constituting the Stepovich lode are crystalline 

limestone, granular scheelite ore which is a replacement of the
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA

limestone quartz pegmatite, and silicated mica schist. The distribution of these rocks in the lode is shown on plates 25 and 26. The" 

silicated rock includes silicated mica schist and a small amount of 

granular scheelite^bearing rock, which, however, does not contain 

enough seheelite to be classed as ore.

The crystalline limestone occurs as discontinuous, irregular bodies 

along the same stratigraphic horizon in the schist. The average 

thickness of the limestone is about 2 feet, although in the crests or 

troughs of folds the thickness is as much as 10 feet. The limestone 

is white to gray and is granular in texture. It is the host rock to the 

granular seheelite ore at places of intersection by quartz pegmatite. 

Small cavities in the limestone have been exposed by the underground 

workings of the deary Hill Mines Co.

The granular seheelite ore forms irregular lenses, which replace 

crystalline limestone. The ore consists of a granular aggregate of 

typical contact-metamorphic minerals, including predominant amounts 

of seheelite, quartz, diopside, and hornblende. A variety of other 

minerals have been identified microscopically, including calcite, 

epidote, clinozoisite, oligoclase, anorthoclase, muscovite, biotite, 

chlorite, apatite, sphene, vesuvianite, axinite, garnet, and meliphanite. 

The last four minerals are rare. The presence of the berylliumcon taming mineral melaphanite was further confirmed when beryllium 

was detected spectographically hi the ore.

Scheelite-bearing quartz pegmatites Occur hi places as stringers 

parallel with the lode and are gradational with the granular seheelite 

ore. These quartz pegmatites are continuous with pegmatites that 

strike N. 40°-60° W. and dip about 60° NE., where they intersect 

the lode. As pointed out on page 188, these quartz pegmatites were 

probably derived from the porphyritic granite, shortly after its emplacement.

The silicated mica schist is a dense-textured thin-bedded rock with 

beds ranging from % to 1 inch in thickness. Vuggy limonitic seams 

about one-eighth inch thick separate the individual beds. Sparse 

grains of seheelite are also found along these vuggy limonitic seams. 

The massive part of the rock contains nearly the same assemblage of 

silicates, that are found in the granular ore. The silicated mica schist 

is usually found in the hanging wall above the ore, and, because it is 

thin bedded, generally requires timbering to prevent its collapse.

Two other rock types, green amphibolite and silicified schist, occur 

in the vicinity of the lode. In the Cleary Hill Mines shaft, green 

amphibolite is exposed hi the footwall of the lode below* the 50 level, 

where it is at least 20 feet thick (pi. 25). The amphibolite appears to 

be a concordant basic intrusion or flow that was later metamorphosed. 

It was more competent than the enclosing beds during folding and

406511 57 3
192 MINERAL BESOURCES OF ALASKA

yielded by fracture rather than flowage. Hornblende is the principal 

mineral of the amphibolite, but minor amounts of sphene, albite, 

orthoclase, quartz, calcite, pyrite, and pyrrhotite are present also. 

About 100 feet north of the lode the schist is silicified and is cut by 

many small quartz veinlets. The silicified schist characteristically 

weathers to a sandy soil.

STRUCTURE

The strike and dip of the bed constituting the Stepovich lode average about N. 70° E. and about 35° NW., respectively. Variations 

in the strike, caused by "rolls" or secondary flexures, range from N. 15° 

E. in the Cleary Hill Mines adit (pi. 25) to N. 50° W. in the face of 

the west drift on the 150 level (pi. 25). Variations in the dip are largely 

the result of drag folding along the crystalline limestone. Dips 

ranging from 70° NW. through horizontal to 15° SE. have been 

recorded. A major drag fold is found in the main shaft workings of 

the Stepovich mine; its crestline and trough, indicated by the appropriate symbols on plate 25, are horizontal, or nearly so. The drag 

fold disappears along the strike to the northeast, inasmuch as only a 

flattening of dip to the northwest is found in the easternmost raise in 

the east drift of the 150 level. The drag fold extends southwest beyond 

the limits of the mine workings. This drag fold was probably localized 

by the association of incompetent limestone of the lode with the more 

competent sill-like intrusive of amphibolite in the footwall (sections 

A-A' and D-D', pi. 25).

The lode is cut by several northward-striking faults, dipping steeply 

northeast. The direction of movement could not be determined 

along the faults. The horizontal shift of the lode along the major 

faults ranges from about ten to several tens of feet. In the vicinity 

of the Stepovich mine the shift of the lode along adjacent faults is in 

opposite directions, but toward the eastern part of the lode, from 

Bureau of Mines trench 4 to 24, the shift has been progressively 

southward (pi. 24). Some of the faults are inferred by offsets in the 

lode between adjacent trenches in which the lode is exposed.

GROUND-WATER LEACHING OF SCHEEITTE

There was some evidence in bulldozer trenches that smaller grains 

of scheelite in weathered permeable parts of the Stepovich lode have 

been partly or completely dissolved by descending ground water. In 

the zone of weathering, which extends to about 10 feet in depth, 

scheelite grains, less than 1 mm in diameter, are embedded in a spongy 

brownish-black matrix, consisting in part of limonite and hydrated 

manganese (?) oxides. On close examination, the scheelite is seen to 

be etched and pitted. Some of the crystals are friable remnants from 

which most of the inner parts appear to have been dissolved. In
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 193

other places, irregular masses of nonporous scheelite-bearing rock are 

enclosed in spongy dark rock, barren of scheelite. This spongy rock 

has not been recognized at depth and is probably the product of weathering. Thin incrustations of scheelite also occur along joints in 

more massive parts of the lode where it grades updip into the spongy 

rock. These incrustations have not been recognized at depth, and 

they may be the result of redeposition of scheelite from'solution. 

These observations were made on the lode mainly near the Gilmore1 

Dome summit, on which a deep residual soil has accumulated since 

probably some time during the Tertiary, inasmuch as no Pleistocene 

glaciation has occurred in the Fairbanks district. It would seem, 

therefore, that the effects of possible scheelite leaching are found at 

the place where expected, namely, in a portion of the lode that has 

been exposed to weathering during a long period of time.

Descending ground water, particularly if it is slightly acid, may 

have dissolved the scheelite at Gilmore Dome. Scheelite is sparingly 

soluble even in pure water (0.027 gram'per liter) (Seidell, 1940, p. 347) 

but is somewhat more soluble in a 0.1 normal solution of sulfuric acid 

(H2SO4) (Gannett, 1919, p. 71). No sulfide mineral that might serve 

as a source of sulfuric acid has been observed in the Stepovich lode, 

but sparse pyrite, from which sulfuric acid would form on oxidation, 

might have been oxidized to form the limonite of the spongy rock. 

Moreover, sparse sulfur, probably in pyrite, ranges from 0.04 to 0.23 

percent (p. 198) in ore samples taken from the Stepovich lode. Hence, 

a sparse amount of sulfuric acid would be formed in descending ground 

water on oxidation of the pyrite.

Scheelite might also have been dissolved during a long period by 

carbonic acid after the pyrite had been completely oxidized. The 

generally cool, moist environment on Gilmore Dome would cause an 

increase of carbon dioxide in the ground water. The resulting carbonic acid (H2CO3) might react with scheelite (CaWO4) in the following manner:

2H2C03+CaW04 |?±Ca(HC03) 2+H2W04.

Although both the reactants and the products are only slightly ionized 

and slightly soluble, a continuous supply of carbon dioxide-charged 

ground water over the long period of time during which the deposits 

have been exposed to weathering would shift the reaction toward the 

right and remove scheelite from more permeable parts of the lode. 

That scheelite does dissolve in the proper ground-water environment 

is also suggested by Hess (1917, p. 64) and by Emmons (1917, p. 432) 

in their observations of botryoidal scheelite coatings, which they regard as of supergene origin.
194 MINERAL RESOURCES OF ALASKA

DISTRIBUTION OF SCHEEIITE

The Stepovich lode was traced by the Bureau of Mines in bulldozer 

trenches for 1,700 feet east and 500 feet west of the inclined shaft 

sunk by the Cleary Hill Mines Co.

The best grade and most numerous ore shoots are concentrated in 

a zone extending about 350 feet east and 200 feet west from the Cleary 

Hill Mines shaft and an unknown distance down the dip of the lode.

About 35 percent of the underground workings that extend from 

the Cleary Hill Mines shaft has been on granular ore approximately 

lYz feet thick. Several pegmatitic quartz veins intersect the lode at 

the shaft, which apparently has been sunk on the richest ore shoot 

(section A-A', pi. 25). Granular ore ranging from 1 foot to \% feet in 

thickness was exposed in Cleary Hill Mines trenches 4, 5, and 6, at 

distances of 100 feet, 200 feet, and 300 feet, respectively, east of the 

shaft. Except in the floor of the 150 level and in the face of the west 

drift, all the ore exposed in 1943 has been mined. The old east shaft 

sunk in 1916 (pi. 25) also passed through ore. According to Mertie 

(1917, p. 421),

The development work consists of a 75-foot inclined shaft along the cleavage of 

the country rock, which, though irregular, strikes in general about N. 70° E. and 

dips 33° N. The ore shoot which is followed by the inclined shaft, is 10 feet wide 

and from 4 to 6 feet high.

The stope and the old drift shown on plate 25 were completed after 

Mertie's visit in 1916. Data on these older workings were obtained 

from the Cleary Hill Mines Co., whose workings early in 1944 intersected those made during World War I.

The caved west shaft also passed downward through a number of 

ore shoots. Chapin and Harrington (1919, p. 325-326) report that

The vein ranges in thickness from 2 to 12 feet and more, but the richest ore is 

confined to lenses from 2 to 5 feet thick * * * Thin stringers of scheelite-bearing 

quartz of later (?) origin than the* replaced rock follow the bedding planes sand 

cut across them.

The mine is being developed by an inclined shaft driven along the vein. In 

September 1917, this shaft had been extended for 160 feet and dips at an angle 

of 40° to 18°. In places the shaft widens out to stopes and chambers, and the 

lower part has been opened to a width of 40 feet.

From Chapin's description it appears that these scheelite ore shoots 

are similar to those in the Cleary Hill Mines shaft. The lode, however, in trenches 1 and 2 (pis. 24 and 25), 70 feet west and 40 feet 

east, respectively, from the caved west shaft, contains limestone and 

silicated mica schist but no granular ore.

Beyond the limits of that part of the lode 350 feet east and 200 

feet west from the Cleary Hill Mines shaft, the lode is narrower, the 

ore shoots are more widely spaced, and the ore is lower in grade. 

Trenches 12 and 13, excavated by the Bureau of Mines approximately
TUNGSTEN DEPOSITS IN. THE FAIRBANKS DISTRICT, ALASKA 195

330 feet and 500 feet west of the Cleary Hill Mines shaft (pis. 24 and 

26), exposed 15 inches and 8 inches, respectively, of brownish-black 

friable weathered material containing sparse grains of scheelite, together with 1 small specimen of unweathered granular ore containing 

an estimated 2 percent of WO3 . The presence of unweathered nonporous granular ore in weathered dark friable rock suggests that most 

of the scheelite originally in this weathered material may have been 

removed by ground-water leaching. The Stepovich lode could not be 

positively identified in any trenches west of trench 13a, although 3 

silicated zones containing sparse scheelite are recognized in trenches 

14-18 (pis. 24 and 26).

A pit in Cleary Hill Mines trench 8, which is 550 feet northeast of 

the shaft, has partly exposed an ore shoot (pi. 26) that has the form of 

a drag fold. The top side of the shoot is in the residual mantle. 

This shoot is probably comparable in size to the major ore shoots in 

the lode and hence may extend as much as 50 feet west of the pit.

Shallow underground work on the lode in the 1943 adit (pis. 24 and 

25) exposed 3 small shoots (pi. 25) with an aggregate of about 10 tons 

of. ore. Just above the 1943 adit the part of the lode exposed in 

trenches 1 and 2 contains only sparse grains of scheelite (pi. 25). The 

lode is unexposed for 80 feet ea^t of the portal of the 1943 adit.

Trenches 4-10 across the lode and trench 20 along its strike from 80 

to 580 feet east of the 1943 adit have exposed the lode for a distance of 

420 feet (pis. 24 and 26). This part of the lode has been faulted at 

3 places, but the only fault of any apparent significance is exposed in 

trench 20 in a pit midway between trenches 4 and 5 (pis. 24 and 26). 

Two ore shoots and 2 small lenses of scheelite-bearing rock have been 

exposed in the bottom of trench 20. One of the shoots with an average 

width of 1.1 feet is exposed in trenches 4 and 20 for a total distance of 

60 feet. The eastern and western ends of this shoot are not exposed, 

although to the east the shoot terminates within a few feet of an inferred fault (pi. 26) of about 15 feet displacement. The other shoot 

is exposed in trenches 6 and 20 for a distance of 70 feet (pi. 26); it has 

an average width of slightly over 2 feet. The dip of this shoot ranges 

from horizontal to 30° toward the north. A narrow zone of scheelitebearing rock is exposed in trench 7 and in pits along trench 20 for 

40 feet (northeastward from trench 7, pi. 26). The average thickness 

of the zone is less than 0.7 foot, and the ore is low grade. In pit W of 

trench 20, about midway between trenches 8 and 9, there is exposed 

the western part of a small lens of ore not more than 12 feet in length. 

The widths of the ore in the east side of pit W is 1.5 feet.

In the next 350 feet east of the offset recognized between trenches 

10 and 11, the lode is again exposed for 150 feet in trench 22 (pis. 

24 and 26). In this distance several small discontinuous high-grade
196 MINERAL RESOURCES OF ALASKA

lenses of ore are present. Most of the lenses are only a few feet in 

length and average about 0.6 foot in width. The longest exposed 

shoot, 17 feet in length, is in trench 22 between pits A and B (pi. 26). 

In trench 22 and Other nearby trenches, the schist and the lode have 

been weathered and limonite stained so that the lode cannot easily be 

distinguished from the country rock. It appears from a slight offset 

of the silicified schist between trenches 19 and 24 (pi. 24) that the 

lode may be just south of trenches 23 and 24.

Sporadic small lenses of silicated rock containing scheelite are in 

the footwall and the hanging wall, at distances generally within 50 feet 

of the main lode (section A-A', pi. 25; trenches 13 and 14, pi. 26). 

These lenses are low grade, probably containing less than 1 percent of 

WO8, and range from a fraction of an inch to about 1 foot in width and 

from a few feet to possibly 20 feet in length.

The dumps from 4 pits 1,050 to 1,200 feet east of trench 24, which 

is the easternmost Bureau of Mines trench exploring the lode consist 

chiefly of garnetized rock with sparse scheelite (pi. 24).

LOCALIZATION OF OEE SHOOTS

Two main factors that probably cause the localization of the shoots 

of granular ore in the Stepovich lode are the tendency of the crystalline 

limestone to flow under regional stresses to loci of lower pressure at the 

crests and troughs of minor flexures, and the introduction of tungstenbearing solutions through the fissures that are now filled with quartz 

pegmatite. At few mines is the relationship between the agents of 

transportation and deposition of ore material as well shown as at the 

Stepovich mine. The quartz pegmatites contain scheelite in increasing 

abundance as the crystalline limestone zone is approached, and they 

are in many shoots gradational with the granular ore. In the Cleary 

Hill Mines shaft, the quartz pegmatite "feeders" appear to have been 

"dammed" by the limestone, inasmuch as the granular ore shoots 

seem to "mushroom" around the zone of intersection.

The green amphibolite (p. 191) was possibly a local factor accounting for the drag folding of the limestone, the greater abundance of 

the "quartz pegmatites, and the consequent richer ore shoots in the 

lode near the summit of Gilmore Dome. The amphibolite apparently 

is confined to the footwall of the lode only in the vicinity of the 

Cleary Hill Mines workings near the summit of the Dome. The 

hypothesis is offered that the competent brittle amphibolite first 

caused greater concentration of the incompetent limestone at the loci 

of minor flexures during periods of compressional stress *nd then 

shattered more than the surrounding less competent schist, thus permitting influx of. tungsten-bearing pegmatitic solutions. The association of amphibolite, limestone drag folds, abundant pegmatites,
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 197

and abundant ore shoots lends weight to this hypothesis and might 

presumably serve as a guide to locating additional ore shoots 

especially when, according to Joesting and Anderson,1 a magnetic 

anomaly, detectible by magnetometer survey, is associated with the 

amphibolite.

GRADE

Eighty-eight samples of scheelite-bearing rock were taken from the 

Stepovich lode, 67 by the Bureau of Mines and 21 by the Geological 

Survey. The latter, consisting of 18 channel samples and 3 grab 

samples, were analyzed in the chemical laboratory of the Geological 

Survey. The analyses of the Bureau of Mines samples were made by 

the Territorial Department of Mines assay office at Fairbanks, 

Alaska. The location, width, and tenor of all channel samples taken 

of the Stepovich lode are shown on plates 25 and 26. The analyses 

of 9 channel samples taken from the upper part of Cleary Hill Mines 

shaft are also shown on plate 25.

The weighted average tenor of 32 channel samples taken in the 

workings of the Cleary Hill Mines shaft and in Cleary Hill Mines 

trenches 4, 5, and 6 across an average width of 1.5 feet is 6.1 percent 

of WO3 . Two samples, containing 13.96 and 23.49 percent of WO3, 

raise the average grade nearly 1 percent; therefore 5 percent of WO3 

probably is a more accurate estimate of the average tenor of the ore 

shoots. However, mined ore contained somewhat less than 5.0 percent of WO3 , mainly owing to an admixture of the barren silicated 

schist from the hanging wall. The high-grade ore mined in 1942 from 

the first 50 feet of the Cleary Hill Mines shaft contained 4.58 percent 

of WO3 . A composite grab sample taken from the surface of the ore 

dump from the 150 level was found by the Geological Survey to contain 3.21 percent of WO3. Some ore is lost in blasting the waste rock 

before removing the ore. A composite grab sample of the fine material (below K-inch mesh) in the waste dump from the 150 level 

contained 0.28 percent of WO3 .

The ore shoots in the lode farther from the inclined shaft than those 

described above are somewhat lower in grade. A grab sample from10 tons of ore mined from the first 110 feet of the 1943 adit contained 

0.59 percent of WO3 . The weighted average of the 2 large ore shoots 

exposed in trench 20 (pi. 26) is 2.25 percent across an average width 

of 1.6 feet. The analyses of scheelite ore in the lode farther to the ' 

east have not been averaged because the ore is in small separated pods.

Analyses of the ores for constituents other than WO3 also were made 

in the chemical laboratory of the Geological Survey. Twelve samples 

of ore had an average phosphorus content of 0.20 percent. The maxi1 Joesting, H. R., and Anderson, Eskil, 1943, Preliminary report on scheelite deposits in the Fairbanks 

district: Juneau. Alaska, Alaska Terr. Dept. Mines files, 10 p.
198 MINERAL, RESOURCES OF ALASKA

mum content of phosphorus allowed in concentrates by the Metals 

Eeserve Company without penalty was 0.05 percent. Scheelite concentrates prepared from this ore, however, are likely to have a much 

lower content of phosphorus than the ore, because the phosphorus is 

largely in minute grains of apatite embedded in, quartz, which is 

eliminated in the gravity concentration of the scheelite. In beneficiation tests by the U. S. Bureau of Mines (Thorne and others, 1948, 

p. 17-22), the phosphorus content was reduced to 0.04 percent. The 

other objectionable constituents of the ore are in such small amounts 

that none of them would subject the concentrates to any smelting 

penalty. Average analyses of 7 ore samples for minor constituents 

are given in the table below.

Minor constituents (in percent} in ore from the Stepovich lode 1

Sample no.

42AMtll7 -.....-.... 

42AMtl57.._ _-_..

42AMt20fi....... ............

42AMt297-. . .........

42A013- . .. .. .......

42A057- - _ ...

42AK111. ........... _ ....

WOa

5.64

.51

23.49

2.50

1 84

9 4Q

1.37

26.41

MoOa

0.015

.015

.015

.02

.02

.06

f!9

0.024

S

0 04

.07

.23

.10

.14

09

.17

0.12

PiOs

0.27

.73

.27

.17

91

19

.28

a

OQ

As

0.01

007

.01

.01

no

.01

.01

±0.01

MnO

0.11

1.08

.05

.09

KK

91

84

n 4.9

Sb

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Tr.

Be

Tr.

Tr.

Tr.

Tr.

Sn

Tr.

i Mertie, J. B., Jr., and Overstreet, W. C., 1943, Tungsten deposits of the Fairbanks district, Alaska: 

U. S. Geol. Survey war minerals rept., p 8. [Unpublished.] 

J Ore mined to end of 1942 reported to have mean tenor of 4.58 percent WOa.

42AMtll7. West wall of inclined shaft, 23 feet from surface. First ore shoot.

42AMtl57. Opencut 5, about 200 feet east of the portal to inclined shaft.

42AMt206. West wall of inclined shaft, 38J^ feet from surface. Second ore shoot.

42AMt297. Face of east drift, 19 feet from inclined shaft.

42A013. Opencut 4, about 100 feet east of the portal of inclined shaft.

42A057. North wall of east drift, 10 feet from inclined shaft.

42AK111. Opencut 6, about 360 feet east of the portal to inclined shaft.

The last three elements in each sample, antimony, beryllium, and 

tin, were identified spectrographically. Spectrographic analyses also 

were made for copper, lead, bismuth, zinc, silver, cerium, and thorium, 

but none of these metals were detected.

The irregular size, shape, and distribution of the ore shoots render 

highly speculative any estimate of ore reserves. Hence, ore reserves 

of the Jobnson-Stepovich lode belong in the category of inferred ore. 

Ore shoots are common in the lode for 1,600 feet of strike length that 

extends about 500 feet west and 1,100 feet east of the Cleary Hill 

Mines shaft. If the lode extends 800 feet downdip (half the strike 

length, in accordance with general practice), a few tens of thousands 

of WO3 units may be inferred in ore shoots ranging in WO3 conteat 

from about 0.5 percent to slightly more than 5 percent. Several 

thousand W03 units are likely to be recovered from high-grade shoots 

near the Cleary Hill Mines Co. workings, where quartz pegmatite 

"feeder" dikes intersect crystalline limestone host rocks.
TUNGSTEN DEPOSITS IN THE EAIRBANKS DISTEICT, ALASKA 199 

CCXLBEKT LODE

Fourteen claims were located on and near the Colbert lode and were 

under option to the Cleary Hill Mines Co. during 1943. The dis.- 

covery pit, which contains the westernmost exposure of the lode, is 

1,000 feet S. 30° E. from Cleary Hill Mines shaft. During 1943 the 

lode was traced by the Bureau of Mines for 2,000 feet east from the 

discovery pit by 18 bulldozer trenches. Two trenches were also 

excavated on a narrow silicated zone nearly 200 feet north of the 

middle part of the main lode (pi. 24).

The Colbert lode dips 35°-45° NW. and has been offset a few tens 

of feet at its western end, presumably by crosscutting faults similar 

to those cutting the Stepovich lode. The thickness of the Colbert 

lode is extremely variable; it pinches out in places and is as much as 

50 feet wide hi trench 9 (pi. 27). The Colbert lode is much lower 

grade than the Stepovich, probably because the ore replaces mainly 

calcareous schist rather than crystalline limestone, although in the 

wider parts of the lode small fine-grained limestone remnants are 

present. It is also possible that temperature and pressure may have 

been too high during the tungsten metallization to permit the deposition of high-grade scheelite ore, because of the nearness of the Colbert lode to the porphyritic granite (pi. 23).

The three main types of rock are dense banded silicated schist, 

pink garnet tactite, and granular grayish-green silicated limestone. 

The dense banded rock consists of light-gray bands of quartz, oligoclase, a little orthoclase, sphene, and apatite; and greenish-gray 

bands of diopside, clinozoisite, calcite, hornblende, chlorite, epidote, 

biotite, and muscovite. These bands in places are separated by 

black vuggy seams containing many small grains of scheelite. The 

garnet tactite consists largely of garnet with minor amounts of quartz; 

scheelite was not observed anywhere in the tactite. The silicated 

limestone is granular and consists predominantly of calcite, quartz, 

chlorite, and scheelite, with a few grains of oligoclase and sphene; 

this rock in part comprises the ore shoots in the lode.

Scheelite occurs abundantly in 3 known ore shoots and in many 

widely spaced small pockets of silicated limestone whose maximum 

dimensions are generally less than 1 foot. Scheelite is also present 

as scattered grains in zones as much as 2 feet wide along vuggy seams 

in banded silicate rock and is sparsely distributed throughout the 

width of the lode. One small shoot of ore is partly exposed in the 

discovery pit for a length of 8 feet and a width of 2 feet (pi. 27). 

About 1,000 feet east, of the discovery pit, a second ore shoot is 

inferred for a distance of 40 feet between the pit in trench 4 and pit A 

in trench 6 (pi. 27), although the ore may not be continuous between 

the 2 pits. The third ore shoot is exposed in trenches 10 and 14; it
200 MINERAL RESOURCES OF ALASKA

has a length of 20 feet and a maximum width of 2 feet (pi. 27). East 

of this shoot the Colbert lode is very weakly mineralized and in 

places pinches out completely.

Locations and results of analyses of 25 samples taken by the 

Bureau of Mines and of 3 samples taken by the Geological Survey on 

the Colbert lode are shown on plate 27. The sample taken by the 

Survey in the Colbert discovery trench (pi. 27) also was analyzed for 

several constituents other than tungsten. The chemical analysis, in 

percent,2 is presented in the table below. The weighted average 

tenor of the ore shoots is 1.3 percent of W03 across an average width 

of 1.6 feet.

Tungsten trioxide (WO3) 1. 56

Molybdenum trioxide (MoO3) . 005

Sulfur (S) . 06

Phosphorus pentoxide (P2O6) . 23

Arsenic (As) <. 01

Manganese oxide (MnO) . 51

Antimony (Sb) Tr.

Tin (Sn) Tr.

Copper (Cu) Nil

Lead (Pb) Nil

Bismuth (Bi) Nil

TEULOW PUP PROSPECT

A scheelite zone in a vertical cut 10 feet high was uncovered in 1943 

by Elmer Stohl, William Birklid, and M. S. Anderson in the valley 

floor of Yellow Pup Creek (pi. 24). As seen in the face of the cut, the 

scheelite-bearing zone ranges from 1 foot to 2 feet in width and dips 

steeply to the north. The footwall and hanging wall are weathered 

dark-stained rocks, probably originally garnet tactite. The ore is a 

quartz pegmatite similar to that cutting the Stepovich lode. The 

rock consists of quartz, oligoclase/ muscovite, and scattered grains of 

apatite and scheelite. A 5-ton ore pile beside the opencut was 

sampled by the Geological Survey and found to contain 0.59 percent 

of WO3 .

Many pits and trenches exposing scheelite-bearing garnet tactite 

and green silicate rock were excavated along the western border of 

the Yellow Pup prospect by Charles Murray and Pat Savage. The 

scheelite-bearing silicated zones are approximately on the projected 

surface trend of the Colbert lode eastward (pi. 24), although apparently several mineralized zones parallel to the schistosity are 

present. By extrapolating the trend of the Colbert zone a few 

hundred additional feet eastward, the discovery cut of the Yellow 

Pup prospect also would lie on an extension of the Colbert lode.

* Mertle, J. B., Jr., and Overstreet, W. C., 1943, Ttmgsten deposits of the Fairbanks district, Alaska: 

U. S. Geol. Survey war minerals rept., p. 10. [Unpublished.]
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 201

Three bulldozer trenches (not shown on pi. 24) were excavated in 

September 1944 at the site of the Murray and Savage pits by the 

U. S. Bureau of Mines (Thorne and others, 1948, pi. 25) to explore 

the lode on the Yellow Pup prospect. These bulldozer trenches 

exposed three small east-trending scheelite-ore shoots west of the 

discovery cut, which are similar to those in the Colbert lode.

SCHUBERT PROSPECT

A 35-foot trench, dug by Gus Schubert, exposes the granite-schist 

contact on the divide between Johnson and Gilmore Creeks approximately 0.8 mile S. 67° W. of the Cleary Hill Mines inclined shaft 

(pi. 23). The trench is nearly at right angles to the bedding, which 

strikes N. 35°-40° E. and dips vertically. The bedrock exposed in 

the bottom of the trench from southeast to northwest is as follows:

Feet

Porphyritic granite.___________________________________ 20

Glassy quartz_________________________________________ Yz

Hornfelsic mica schist__-_______________________________ 7 %

Scheelite-bearing silicated limestone and limestone________ 7

The silicated limestone resembles that of the Colbert lode. Scheelite occurs as sj>arsely scattered grains in a 2-inch band within the 

silicated limestone. This prospect is the only place in the Gilmore 

Dome area where scheelite-bearing rock has been exposed at the 

contact zone of the main body of granite.

STEELE CREEK-FIRST CHANCE CREEK AREA

Scheelite occurs at several places on a ridge between the heads of 

Steele and First Chance Creeks (pi. 23) near the western end of the 

large body of porphyritic granite that lies south and southwest of 

Gilmore Dome. The Old Gilmore Road, which joins the present 

Steele Creek Road about a mile from the Steese Highway, follows 

along this ridge. All of these occurrences are within 5 miles of the 

Old Gilmore Road turnoff.

All the tungsten prospects in the Steele Creek-First Chance Creek 

area were examined by Mertie (1917, p. 422-424) and Chapin and 

Harrington (1919, p. 326-327). The following descriptions are based 

largely upon these earlier reports, inasmuch as most of the workings 

were caved when examined in 1943.

The discovery of scheelite deposits on Gilmore Dome in 1915 gave 

an impetus to prospecting for other tungsten lodes. By the summer of 

1916, five prospects, known as the Spruce Hen, Columbia, Blossom, 

Tanana, and Tungsten Hill, had been located. Prospecting on them 

continued by means of adits, shafts, and trenches for 2 or 3 years, but 

these workings are now caved (pi. 28). Only minor development was 

done on the Tungsten Hill prospect; these workings, therefore, are not
202 MINERAL, RESOURCES OF ALASKA

shown on plate 28. All tungsten mining ceased in 1918 with the 

sudden decline in the market price of tungsten ores.

Quartz schist and quartz-mica schist are the most common countryrooks in this area, with less abundant crystalline limestone, hornblende schist, and recrystillized basic igneous rocks. The metamorphic rocks are intruded by the large mass of porphyritic granite 

(pi. 23). The scheelite deposits lie at or near the irregular western 

contact of this granite. Scheelite is disseminated in tactite, silicatedx 

limestone, in and along the edges of granitic and pegmatitic dikes, and 

in small quartz veins which transect the cleavage of the country rock.

SPRUCE HEN PROSPECT

The Spruce Hen prospect lies on the divide between the headwaters 

of Steele and First Chance Creeks (pi. 28). Old development work at 

the Spruce Hen group of claims consisted of two shafts and many 

trenches and prospect pits.

Scheelite mineralization has been traced by pits and trenches for 

over 800 feet. The trend of the mineralized zone, inferred from 

scheelite-bearing rock exposed on the dumps of the workings, is 

N. 60° E. (see inset, pi. 28). More than 1 lode appears to be present, 

but, owing to lack of exposures, it could not be determined whether 

there are 2 parallel lodes or several arranged in echelon. The scheelite 

lode was exposed in 1943 by only 1 pit and 1 trench near the center of 

the workings. In the trench the lode is badly weathered and constitutes part of the mantle rock. The widths of the lode in the pit 

and the trench are 3.2 and 3 feet, respectively. The southwest shaft is 

reported to have been sunk 70 feet along an incline or 30° on a northwest-dipping body of ore 3 feet thick. This is apparently a different 

scheelite-bearing zone from the one exposed in the trench and pit. 

The shaft at the northeast end of the workings was sunk in prospecting 

for gold and did not intersect the tungsten lode.

Small grains of scheelite are disseminated through the lode along 

with abundant garnet, diopside, quartz, clinozoisite, vesuvianite, and 

calcite. Fluorite is also present in the lode. The dump of a pit 60 

feet northeast of the southwest shaft contains blocks of a dark-green 

fine-grained altered igneous rock consisting chiefly of hornblende. 

Some of these blocks contain high-grade concentrations of scheelite in 

zones as much as 6 inches wide. The character, size, and tenor of the 

deposit from which this ore came could not bs determined.

Locations and analyses of 4 lode samples in place and 1 ore dump 

sample from the Spruce Hen lode are shown in the inset of plate 28. 

The ore dump sample contained 0.25 percent of WO3, but this analysis 

is almost certainly low, inasmuch as ore dumps from the lode have 

been sampled many times by prospectors and others, who have 

removed the higher grade specimens of ore (H. R. Joesting, 1943,
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 203

written communication). The 4 samples of the lode in place averaged 

0.44 percent of WO3.

The lode sample containing 0.16 percent of W03 and the ore-dump 

sample were analyzed for several other constituents, including some 

that might prove deleterious in the processing of the ore. These 2 

analyses, in percent,3 are shown in the table below.

Ore

Lode dump

Tungsten trioxide (WO3)_____________ 0.16 0.25

Beryllium oxide (BeO)_____________________ Tr. None

Manganese oxide (MnO)_--_-_______-__-.__ .87 .67

Phosphorus pentoxide (PgOs)______________ Tr. Tr.

Molybdenum trioxide (MoO8)_______________ . 005 . 005

Antimony (Sb)_-____________ ____ Tr. Tr.

Arsenic (As)____________________ <. 01 <. 01

Sulfur (S)________-__.____________________ .54 .10

Lode. West slope of ridge at head of First Chance Creek and 1.4 miles S. 8° E. from mouth of Rose 

Creek. Pit near southwest end of workings.

Ore dump. West slope of ridge at head of First Chance Creek and 1.4 miles S. 8° E. from mouth of Rose 

Creek. Dump ore from shaft at southwest end of workings.

BLOSSOM PROSPECT

The Blossom prospect is about three-quarters of a mile southwest 

of the Spruce Hen prospect and on the same ridge (pi. 28). Workings 

on the Blossom group of claims in 1943 consisted of an inclined shaft, 

10 trenches, and 9 small prospect pits. Five hundred feet southeast 

from these workings, near the top of the ridge, are 2 trenches, an 

inclined shaft, and 2 prospect pits (pi. 28). All the workings at the 

Blossom prospect are caved.

The south shaft was sunk 20 feet vertically, then it was inclined 

at an angle of 30°. No exposures are available in the shaft; but 

when the mine was being developed during 1916, a scheelite-bearing 

layer of weathered schist 3 to 4 feet thick containing rich quartzscheelite stringers was reported. Scheelite is in zones one-fourth 

inch wide in quartz-mica schist along contacts with quartz veinlets 

1 to 3 inches thick.

The north shaft, inclined at an angle of 28°, cuts through quartzbiotite schist, amphibole schist, and a dike of porphyritic granite. 

Scheelite-bearing quartz veinlets, % to 3 inches thick, penetrate the 

quartz-biotite schist and the porphyritic granite. Scheelite also 

occurs in the schist in %-inch zones along the contacts with quartz 

veinlets. Some of the quartz veinlets contain about 25 percent of 

scheelite, but they are less than one-half inch thick and are not 

numerous.

The tungsten deposits on the Blossom prospect are apparently of 

the quartz-stringer type and do not occur in beds of Ume-rich silicates.

»Mertie, J. B., Jr., and Overstreet, "W. O., op. dt., p. 16.
204 MINERAL RESOURCES OP ALASKA

It would seem that the lack of a suitable limestone bed on the Blossom 

prospect accounts for the dissemination of the scheelite in the quartz 

veinlets, which are normally the "feeders" of tungsten-bearing oreforming solutions at the time of ore deposition. Apparently there 

has been some minor localization of the quartz stringers by certain 

beds in the schist complex.

Only ore dumps were available for sampling on the Blossom prospect, and the two best of these were sampled by J. B. Mertie, Jr., 

in 1942. Sample 51 was taken from the ore dump at the caved 

vertical shaft at the northeast end of the workings just above the 

1,850-foot contour (pi. 28). Sample 264 was from the ore dump at 

the pit 20 feet west of the caved inclined shaft near the bend in the 

road at the southern end of the workings. Possibly part or all of 

this ore dump may have come from the inclined shaft. Analyses, 

in percent,4 of these samples are given in the table below.

51 . 864 

Tungsten trioxide (WO3)._____________ 2.02 1.44

Manganese oxide (MnO)__________-___-_-_-_ .12 .01

Phosphorus pentoxide (P2OS)_______________ .45 .13

Molybdenum trioxide (MoOs)__--------_--_ .01 .005

Antimony (Sb).________________.---_.-_ Tr. Tr.

Arsenic (As) _______________._______ .02 <. 01

Sulfur (S)___---_-.._________________ .07 .06

51. Tungsten Hill, about 2^ miles S. 6° E. from junction of Gilmore and Pedro Creeks. North side of 

hill and about 450 feet northwest of Old Gilmore Road. Shaft at northeast end of workings.

264. Tungsten Hill, about 2^ miles S. 6° E. from junction of Gilmore and Pedro Creek. Southeast side 

of hill and about 80 feet west of Old Gumore Road. Pit in workings.

The method of sampling the ore dumps in 1942 consisted of crawling 

over the dumps under a heavy tarpaulin, which excluded most of the 

daylight, and picking up all the pieces of rock which the ultraviolet 

'lamp showed to contain scheelite. The high WO3 content of the 

Blossom prospect samples is due to the selection of those ore specimens, 

for analysis that contained the quartz-scheelite stringers, and hence 

is hardly representative of any large body of rock. The higher P2O5 

content (from apatite) and the lower MnO and S contents of samples, 

from the Blossom prospect when compared with the amounts of these 

constituents in samples from the Spruce Hen prospect would be 

expected in the pegmatite-type quartz-stringer deposit of the Blossom 

prospect, in contrast to the tactite type of scheelite deposit characterized by the Spruce Hen prospect.

TANANA PROSPECT

The Tanana prospect is located in Tungsten Gulch, a tributary to> 

First Chance Creek (pi. 28), at an altitude of about 1,450 feet. Workings visible in' 1942 and 1943 included a caved shaft and several small

4 Mertie, J. B., Jr., and Overstreet, W. C., op. cit., p. 16.
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTBICT, ALASKA 20,&

prospect pits. These openings revealed little geologic information^ 

for they had become filled with slope wash and were overgrown with; 

vegetation.

Mertie (1917, p. 422) examined the prospect in 1916 when the workings were accessible and wrote the following description:

The country rock on this claim is a quartzite schist, the cleavage of which strikesN. 30° E. and dips 35° NW. The lode consists of a mineralized zone, 3 feet 

thick, which lies parallel with the major structure of the country rock. It is the 

structure of the schist, in fact, which has determined the site of the ore deposition. 

The scheelite occurs in stringers of soft, decomposed, iron-stained schist, from 2 

to 6 inches in width. Many of these stringers contain little quartz-scheelite 

veinlets, which are very rich in tungsten and carry also some gold. The stringers 

of decomposed schist are said to carry both scheelite and gold. The country rock 

separating the schist stringers in the lode also carries a little scheelite, possibly 

as much as 1 percent. A specimen of scheelite-bearing pegmatite, taken from; 

the bottom of the incline, »shows the ultimate genetic connection of the deposit 

with granitic rocks.

A gold quartz vein striking N. 8° W. and dipping 60° E. cuts the schist and the 

scheelite lode above described. This vein carries gold in about the same amount, 

as the scheelite lode. In view of the fact that gold and scheelite do not appear to* 

have been deposited synchronously at the other properties visited, it is probable 

that the gold in this scheelite lode is a result of local enrichment by the gold quartz, 

vein. Both structural and mineralogic data therefore point to the conclusion 

that the scheelite mineralization took place before the formation of the gold 

quartz veins, at least at this particular locality.

TUNGSTEN HELL PROSPECT

The Tungsten Hill prospect was located in 1916 on the southwest 

side of Tungsten Gulch opposite the Tanana prospect. No workings 

are shown on plate 28, because the few prospect pits dug in 1916 had 

been completely obliterated by the time of Mertie's visit in 1942 and 

the writer's in 1943. The pits on the Tungsten Hill prospect were 

examined in 1916 by Mertie (1917, p. 424) who writes:

Four scheelite lodes had been discovered on these claims by August, 1916, and 

it is likely that others are present. On the Grand Duke Nikolas claim a scheelite 

lode in the schist country rock had been exposed in an open cut. This deposit 

consists of 6 to 8 feet of decayed schist, carrying scheelite. Vein quartz containing a little gold is also present, cutting the mineralized zone.

On the Tungsten No. 1 claim another open cut had been made in a country 

rock of mica schist and quartzite schist. A zone mineralized by scheelite is 

present, but the width of the lode was not apparent from the work done.

On the General Joffre claim a scheelite lode, 14 feet wide, has been exposed.. 

The lode as a whole was considered low-grade ore; but it contains in the central 

part an 18-inch stringer of decayed schist, which is of considerably higher grade.

These claims certainly deserve further prospecting, for they are as advantageously situated with regard to the granite as other scheelite claims in the 

district on which workable lodes have been developed.

COLUMBIA. PROSPECT

The Columbia prospect is near the head of Steele Creek Valley. 

Workings are located on the west side of the valley through altitudes.
206 MINERAL RESOURCES OF ALASKA

ranging from 1,500 to 1,660 feet (pi. 28) and consisted in 1943 of 2 

adits, 4 trenches, a prospect pit, and 2 shafts, all caved. In 1916, 

the upper adit was driven 80 feet along a 3-foot zone of decayed schist 

containing quartz-scheelite stringers. The zone strikes N. 20° W. 

and dips 30° E. Porphyritic granite forms the hanging wall. Several 

fragments of quartz-mica schist cut by scheelite-bearing quartz were 

found in 1943 on a large dump outside the upper adit. The lower 

adit, intended to intersect the lode at a lower altitude, was entirely 

within the granite. No information is available on the kind of rock 

that was exposed in the shafts.

PEDRO DOME AREA

Four types of scheelite deposits have been found at scattered intervals along the southern side of the Pedro Dome area (pi. 23) in a belt 

of gold-tungsten mineralization, which extends" about N. 65° E. from 

the head of Moose Creek, a headwater tributary of Dome Creek, to 

the upper valley of Fan-banks Creek, a distance of about 8 miles. 

Scheelite occurs chiefly hi gold quartz veins which cut thin crystalline 

limestone beds, a few inches in thickness, or calcareous schist. The 

second type of scheelite deposit occurs as wall-rock replacements of 

these calcareous beds. The third type is represented by a single 

contact-metamorphic deposit which probably is close to the source of 

the tungsten-bearing solutions. The fourth type of scheelite deposit 

is genetically closest to the source of the tungsten-bearing solutions 

and consists of sparse scheelite grains in a pegmatite derived from the 

porphyritic granite.

The vein and limestone wall-rock types of scheelite deposits are 

closely related and are found intimately associated in the Wackwitz, 

Cleary Hill, and other gold mines. The contact-metamorphic type 

is found on the Leslie prospect and the pegmatite type on the Egan.

WACKWITZ MINE

Scheelite in gold quartz veins and in limestone-replacement bodies 

occurs at the Wackwitz mine on the east side of Bedrock Creek, a 

tributary of Cleary Creek (pi. 23). This mine is on the Wyoming 

and Wyoming Fraction claims, about 1,100 feet from the mouth of 

Bedrock Creek. It is reached by a short automobile road which 

branches from the Steese Highway on the northwest side of Cleary 

Creek. According to Mertie and Overstreet,5 a small quantity of 

scheelite concentrates is reported to have been produced as a byproduct of gold mining.

The principal development work at the Wackwitz mine consists of 

3 adits driven eastward into the hill on different levels. The country 

rock is quartz-mica schist, quartzite, and thin limestone beds which

 Mertie, J. B., Jr., and Overstreet, W. O., op. cit., p. 20.
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 207

strike N. 85° W. and dip about 27° N. On the lowest level a vein is 

exposed at intervals along the drift. About 400 feet in from the 

portal, a crosscut extends 380 feet to the south. Three small quartz 

veins and a northward-trending fault zone are exposed in the crosscut. 

At the southern end of the crosscut a 75-foot drift at approximately 

right angles has been driven along the Wyoming vein (also known as 

vein 5), the principal scheelite-bearing vein in the mine. All the 

veins exposed strike approximately east and dip steeply south. The 

middle or main level is a drift on the Wyoming vein for 350 feet 

eastward and then intersects the northward-trending fault. A 100- 

foot crosscut to the south has picked up the Wyoming vein, and a 

drift has been driven 200 feet farther east along the vein. The 

uppermost level was caved when visited in 1943.

Scheelite is rare hi all the veins exposed east of the fault. West of 

the fault, the Wyoming vein contains scheelite in addition to gold. 

In the back of the middle level, the Wyoming vein contains a 6-inch 

scheelite-bearing zone for 70 feet along the drift. It was estimated 

that this zone might contain as much as 0.3 percent of WO3 . In a 

sublevel above the same drift, a small, high-grade ore shoot, formed 

by replacement of fine-grained limestone, measures 1 by 3 feet in 

cross section and was estimated to contain 20 percent of WO3 . This 

replacement-type ore shoot was almost indistinguishable from the 

enclosing fine-grained limestone without the aid of an ultraviolet 

lamp.

Three samples were taken of the scheelite ores at the Wackwitz 

property. One of these, sample 230, is from the scheelite ore dump 

at the portal of the lower adit. This material was taken entirely 

from the Wyoming vein, and hence the sample should represent the 

average tenor of this vein. Samples 231 and 232 were taken from the 

Wyoming vein where exposed in the back of the drift on the lowest 

level. The analyses, in percent, 6 of these samples are presented in 

the table below. No copper, bismuth, or tin was found hi these 

samples, but, by spectographic tests, traces of antimony were found 

in all 3 samples, and a trace of beryllium was found in 232.

	»o m m 

Tungsten trioxide (WOs)-----.----------------- 0.28 0.69 1.64

Molybdenum trioxide (MoO3) __________________ .005 .005 . 005

Manganese oxide (MnO)-_-_-------_-__------- .11 .01 .07

Phosphorus pentoxide (P2 05)_______-__-__.-_-_- .28 Tr. .26

Arsenic (As)__-_---____-__--_-___--_-_------- .80 .70 .61

Sulfur (S)___--_--___--_________-__-____-_-__ .06 .26 .22

230. Dump ore at portal of mine. This ore was mined from the Wyoming vein.

231. Sample taken from face in Wyoming vein, lowest level.

232. Sample taken from face in Wyoming vein, lowest level.

e Mertie, J. B.t Jr., and Overstreet, W. C., op..cit.> p_2t.
208 MINERAL RESOURCES OF ALASKA

The tenor of the Wyoming, or vein 5, is so low that tungsten can 

be recovered only as a byproduct of gold mining.

MIZPAH MINE

Another occurrence of scheelite ore similar to that at the Wackwitz 

mine is on the Black Joe and Mizpah claims of the Mizpah mine, on 

the north side of Fairbanks Creek, west of Too Much Gold Creek 

(pi. 23). The workings on this property were caved and inaccessible 

in 1942 but were described earlier by Mertie (1917, p. 421) :

The country rock is quartzite schist, which strikes N. 20° W. and dips 18° SW. 

The scheelite is present in a quartz vein, which cuts the cleavage of the schist, 

striking N. 80° W. and dipping about 80° S. This is really a gold-tungsten vein, 

for it contains both gold and scheelite. The interesting feature, however, is 

that the two minerals occur in different portions of the vein. Just above the 

60-foot level the vein is 6 inches thick and is a gold-quartz vein, carrying little 

or no tungsten. Just below this level, in the same vein, the quartz is scheelitebearing and the gold is lacking. In reality, there is a scheelite ore shoot in the 

quartz, with a lateral extent along the vein of about 80 feet. At the 80-foot 

level the vein is a low-grade gold-tungsten lode, carrying little gold and much 

less scheelite than at the 60-foot level. The dip of the vein at this point ranges 

from 45° to 85° S. It appears, therefore, that where this quartz vein carries 

scheelite in commercial amount gold is lacking, and that the gold-bearing part 

of the vein is lacking or low in scheelite.

A small amount of scheelite concentrates were recovered in 1916 

from the 6-inch gold quartz vein.7 No tungsten ore was seen on 

any of the old dumps at this property by the Geological Survey 

party in 1942.

CLEARY HILL MINE

During the summer of 1943 a small amount of scheelite was found 

in the Cleary Hill gold mine. The Cleary Hill claims adjoin those of 

the Wackwitz mine on the north and extend from Bedrock Creek 

eastward to Chatham Creek (pi. 23). Nearly all the Cleary Hill 

mine production has been gold ore, although a small amount of 

antimony ore also has been mined. Adits have been driven on the 

Cleary Hill vein at three levels: the uppermost adit, or first level, 

now caved; the Penrose and Swanson adits on the second level; and 

the main adit on the third level. A winze sunk inside the main adit 

connects with the fourth, fifth, and sixth levels. The Penrose and 

Swanson adits on the second level are parallel, having been driven on 

displaced segments of the Cleary Hill vein.

The readily accessible workings of the Cleary Hill mine were 

examined with the ultraviolet lamp to determine the extent of scheelite 

mineralization. Scheelite is present in scattered grams and %-inch 

seams hi the wall rock of the gold quartz vein for 300 feet along the

7 Mertie, J. B.f Jr., and Overstreet, W. C., op. citn p. 22.
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 209

back of the Penrose adit and for 100 feet along the back of the 

Swanson adit. Most of this mineralized rock is estimated to contain 

as much as 0.1 percent of WO3 across a width of 1 foot. Several feet 

of calcareous wall rock along the back of the Penrose adit appeared 

to contain about 1.0 percent of WO3 across a width of 1 foot. The 

wall rock contains thin limestone beds in the part of the Penrose adit 

where scheelite is present.

Scheelite is disseminated in thin beds of crystalline limestone at a 

few places in the lower levels of the Cleary Hill mine. At one place 

on the fourth level crystals occur a foot from a gold quartz vein which 

contains no scheelite. On the sixth level the gold ore contains grains 

of scheelite in a few places.

On the west side of Chatham Creek valley, about three-eighth mile 

east of the portal of the main adit, an inclined shaft has been sunk to 

a depth of about 125 feet on a mineralized zone of limonite-stained 

quartz stringers in weathered schist. The zone strikes N. 60°-70° W. 

and dips 50°-60° SW. The schist in the lower 75 feet of the shaft 

exposes some thin beds of crystalline limestone, which contain 

scattered grains of scheelite. Crystals of scheelite also are sparsely 

distributed in the stringers. This zone does not contain more than 

0.1 percent of WO3 over a width of 3 feet.

The WO3 content of the Cleary Hill vein is 0.1 percent or less, 

which may be too low to attempt recovery of scheelite even as a 

byproduct of gold production. The discovery of scheelite, however, 

in the largest lode-gold mine in the Fairbanks district suggests that 

scheelite may be present hi many of the other lode-gold mines of the 

district.

LESLIE PROSPECT

The Leslie prospect is near the center of the Old Glory lode claim, 

on the west side of Seattle Creek about 2K miles S. 65° W. from the 

summit of Pedro Dome (pi. 23). The property is reached by a 

poor automobile road, about 2 miles in length, which branches eastward from the Elliott Highway near the head of Fox Creek.

The bedrock at the Leslie prospect is quartz-mica schist and quartzite; but a few hundred feet to the north is a tongue of granodiorite, 

which is the western extension of the intrusive mass that forms the 

bedrock at Pedro Dome. The bedrock is metamorphosed as a result 

of its proximity to the intrusive, and a small dike of granodiorite 

crops out in the bottom of the workings. The cleavage of the 

metamorphic rocks strikes N. 10° E. and dips 25° E.

The development work consists of an opencut that is 20 feet long 

and trends east-west. In the center of this cut is a small pit. 

Scheelite-bearing rock is on the north, west, and south sides of this 

pit, but the highest grade rock is on the north side, where the ore is
210 MINERAL RESOURCES OF ALASKA

exposed in a face 4}^ feet high. Scheelite is sparsely disseminated in 

the upper 2% "feet of this exposure, and the ore of higher grade is exposed in the lower 2 feet of the face.

One channel sample of the entire face of 4}^ feet was taken by the 

Geological Survey. The analysis of this sample, in percent,8 is given 

in the table below.

Tungsten trioxide (W03) 0. 48

Molybdenum trioxide (MoO3 ) . 005

Sulfur (S) . 63

Phosphorus pentoxide ^Os) Tr.

Arsenic (As) <! .01

Manganese oxide (Mno) . 01

Antimony (Sb) Tr.

EGAN PROSPECT

About 1 mile S. 30° E. of Pedro Dome, Dan Egan has made a large 

opencutand several smalLtrenches just north of the Steese Highway 

(pi. 23). The country rock is granodiorite, which is cut by small 

pegmatite dikes, less than 6 inches in width, that were derived from 

the porphyritic granite. The dikes crosscross one another but appear 

to have a general westerly strike. Scheelite is sparsely distributed in 

small grains in the pegmatite. The deposit as a whole is extremely 

low grade but is of scientific interest in demonstrating the genetic 

relationship of the scheelite to the porphyritic granite.

MINOR OCCURRENCES OF SCHEEUTE

The dumps of three additional mines, whose workings were inaccessible, were examined with an ultraviolet lamp. Scheelite occurs 

in the Johnson mine near the mouth of Willow Creek in the valley of 

Cleary Creek (pi. 23). A small amount of scheelite also was found in 

the gold quartz ore at the Tolovana mine, about one-half mile west 

of the Wackwitz mine. Scheelite also is associated with the gold 

quartz ore of the Rainbow mine, about one-half mile north of the 

confluence of Skoogy Creek with Twin Creek. Scheelite is probably 

a minor constituent in most of the other gold quartz veins of the 

district.

PLACER SCHEELITE

Scheelite has accumulated with other heavy minerals in placers 

derived from the areas of tungsten mineralization. It has been found 

in many placer concentrates in the Pedro Dome area, particularly in 

the valleys of Dome, Little Eldorado, Bedrock, Chatham, Cleary, and 

Fairbanks Creeks (pi. 23). Placer concentrates near the head of Fox 

Creek con tamed an estimated 90 percent of scheelite (Robert R.Coats, 

1945, oral communication). The lodes of the Gilmore Dome and

8 Mertie, J. B., Jr., and Overstreet, W. O., op. cit, p. 19.
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 211

Steele Creek-First Chance Creek areas also have contributed scheelite 

to nearby streams including Fish, Pearl, First Chance, Gilmore, Rose, 

and Goldstream Creeks.

The United States Smelting, Refining & Mining Co. has saved the 

concentrates from all the material dredged during its operations in the 

Fairbanks district. Two channel samples of the dump containing the 

concentrates were taken, one by the company and the other by the 

Geological Survey. The mean of these shows a content of 0.1 percent 

of WO3 , 2.23 percent of tin, and 0.01 percent of bismuth.

AREAS FAVORABLE FOR PROSPECTING

There remains the possibility of undiscovered scheelite-b earing lodes 

in the Fairbanks district. As a result of this investigation several 

favorable areas for prospecting can be pointed out. The essential 

factors favoring the existence of a potentially productive, scheelitebearing lode are as follows:

1. A small area of porphyritic granite, which represents a truncated 

cupola of a larger body of porphyritic granite. During the consolidation of the granite, a fluid phase containing tungsten hi solution 

migrated into the cupola and out into the country rock.

2. A limestone bed in the metamorphosed sequence at distances 

ranging from % to 1 mile from the area of porphyritic granite. In 

beds of gentle to moderate dip, the limestone bed must be on the 

downdip side of the cupola of porphyritic granite because the cupola 

probably conforms to the bedding and, hence, would underlie beds of 

the country rock on the downdip side.

3. Quartz-rich pegmatite dikes. These usually trend at nearly 

right angles to the contacts between porphyritic granite, country rock, 

and limestone.

4. Local irregularities in the structure, such as drag folds. These 

are not of any value as a general guide, however, until an area of 

scheelite-bearing rock is located. The drag folds, unfortunately, 

cannot be seen until considerable stripping of the overburden has 

been done.

In prospecting for scheelite in the Fairbanks district, the unprospected areas % to 1 mile north of the areas of porphyritic granite 

shown on plate 23 should be examined thoroughly. The areas on the 

downdip side of the porphyritic granite are more favorable, and these 

areas are to the north of the porphyritic granite because the regional 

dip is to the north. Local variations should be anticipated, however, 

and hi those cases the downdip rule should apply. In prospecting 

country rock on the downdip side of the porphyritic granite areas, 

the logical method would be to follow either a limestone bed (commonly a series of disconnected lenses, owing to the plasticity of
212 MINERAL RESOURCES OF ALASKA

limestone under regional stresses), or a pegmatite dike, until the one 

intersected the other. At their intersection a scheelite-bearing ore 

body normally might be expected.

Prospecting for scheelite-bearing lodes in the Fairbanks district 

would be simple, if it were not for the extensive overburden. In 

actual practice, prospecting the country rock on the downdip side 

of the porphyritic granite area could be accomplished best by use of a 

small pesthole auger with one extension, permitting a test hole 12 

feet deep. Bedrock in place is reached generally within this depth on 

ridgetops and hillslopes. On hillslopes scheelite hi the mantle could 

be traced to the source lode, because frost action causes the mantle, 

including any scheelite-bearing rock, to migrate downslope from the 

bedrock source. The mantle removed by the auger could be examined 

by means of an ultraviolet lamp. Hillsides could be covered by using 

a 100-foot grid spacing of holes. On flat or gently dipping surfaces 

near the ridgetops closer spacing of holes would be necessary. Areas 

around any holes yielding scheelite-bearing float could be examined 

more intensively with the auger until the bedrock source was located. 

Hand-dug or bulldozer trenches at the bedrock source then could 

follow the test drilling by auger. Permanently frozen ground would 

offer no barrier except possibly on lower slopes near valley bottoms.

The Gilmore Dome area has been prospected rather thoroughly 

so that there is little likelihood of any new discoveries in that vicinity. 

The Steele Creek-First Chance Creek area should be prospected 

carefully, however, as there is a fair possibility of finding undiscovered 

scheelite lodes north of the narrow tongue of porphyritie granite 

(pi. 23). In the Pedro Dome area, the country rock north of the two 

areas of porphyritic granite (pi. 23) should be prospected thoroughly. 

The area surrounding the small mass of porphyritic granite near the 

head of Fox Creek (pi. 23) almost certainly is mineralized with 

scheelite, inasmuch as placer concentrates from gold mining in that 

area contained 90 percent of scheelite (see p. 210). Finally the country 

rock surrounding any small unmapped areas of porphyritic granite 

should be prospected.

LITERATURE CITED

Brooks, A. H., and others, 1916, Mineral resources of Alaska: U. S. Geol. Survey

Bull. 642, 279 p. 

Chapin, Theodore, and Harrington, G. L., 1919, Mining in Fairbanks, Ruby,

Hot Springs, and Tolstoi districts: U. S. Geol. Survey Bull. 692, p. 321-353. 

Emmons, W. H., 1917, The enrichment of ore deposits: U. S. GeoL Survey Bull.

625, 530 p. 

Gannett, R. W., 1919, Experiments relating to the enrichment of tungsten ores:

Econ. Geology, v. 14, p. 68-78. 

Hess, F. L., 1917, Tungsten minerals and deposits: TJ. S. Geol. Survey Bull. 652,

85 p.
TUNGSTEN DEPOSITS IN THE FAIRBANKS DISTRICT, ALASKA 213

Hill, J. M., 1933, Lode deposits of the Fairbanks district: U. S. Geol. Survey

Bull. 849-B, p. 29-163. 

Mertie, J. B., Jr., 1917, Lode mining in the Fairbanks district, Alaska: U. S.

Geol. Survey Bull. 662-H, p. 403-424.

 1937, The Yukon-Tanana Region: U. S. Geol. Survey Bull. 872, 276 p. 

Prindle, L. M., Katz, F. J., and Smith, P. S., 1913, A geologic reconnaissance of

the Fairbanks quadrangle, Alaska: U. S. Geol. Survey Bull. 525, 220 p. 

Seidell, Atherton, 1940, Solubilities of inorganic and metal organic compounds;

a compilation of quantitative solubility data from the periodical literature:

New York, D. Van Nostrand Co., Inc., 3d ed., v. 1, 1,698 p. 

Thorne, R. L., and others, 1948, Tungsten deposits in Alaska: U. S. Bur. Mines

Rept. Inv. 4174, 51 p.

INDEX

Page 

Accessibility of deposits........._...... 180; pi. 23

Acknowledgments______________ 184

Analyses of ore samples:

Blossom prospect-.____________ 204 

Colbert lode.. .................... 200; pi. 27

Leslie prospect._______________ 210 

Spruce Hen prospect..._________ 203 

Stepovich lode ___.__._ 198; pis. 25, 26 

Wyoming vein..______________ 207

Bedrock Creek....____.. 188, 206, 208, 210: pi. 23

Bureau of Mines...._____________ 189,

190,192,194,196,197, 198,199, 200, 201

Chapin, Theodore, and Harrington, G. L.,

quoted._______________ 194 

Chatanika River............._.....__ 181; pi. 23

Chatham Creek.............._ 188, 208, 210; pi. 23

Claims:

Black Joe................................. 208

Mizpah.................................. 208

Old Glory lode..-.---------.-----.._ . 209

Cleary Creek............ 183,188,190,206,210; pi. 23

Cleary Hill Mines Co....--..-.-.... ... 183,184,

188,189-190,191,194-195,196,197,198,199 

Climate........................ ......... 182-183

Colbert lode.......__... 184,189,199-200; pis. 24,27

Description of deposits____.______ 187-211

Dikes:

granodiorite.________________ 209

porphyritic.__.______________ 186

quartz pegmatite.___________ 186,188,

191,196,198,200,211,212

Dome Creek..................... 188,206,210; pi. 23

Drainage.___.....___.__....._... 181-182

Eldorado Creek_____________ 188; pi. 23 

Elements:

antimony...._..... _......... 198,207,208

beryllium. ..................... 191,198,203,207

bismnth...______...._...._ 200,207,211

gold. 183,187,188,205,206,207,208,209 

phosphorus-____ 197-198,200,203,204,207,210 

sulfur... . 193,198,200,203,204,207,210 

tin__......... ................ 198,200,207,211

Elliott Highway .. 209; pi. 23 

Engineer Creek....._........___ 186,188; pi. 23

Ester Creek__.__. ....-....___.. 188

Fairbanks Creek.. __.__ 181,188,206,208,210 

Faults 187,192,195,199,207 

Field work..______.______.____ 184 

First Chance Creek..... 188,201,202,204,211 

Fish Creek. . . 181,188,211 

Folds, drag...- ___....... 192,196,211; pi. 25

Fox Creek.

Page

188,209,210,212

Geology . . . 184-186

Gilmore Creek.. . 181,188,201,211 

Gilmore Dome area:

description __.......... ... 188-201

field work.. ....__ -..____.__.. 184

history 183

location..... .. 180; pi. 23

placer scheelite......__._... 188,210-211

production of WOj.------------- 183,187,190

rocks . 185,186,187

structure._.__... .. 187 

Goldstream Creek.__.....___..... 181,188,211

Grade of scheelite-bearing rock.. 197-198, 200, 203,

204,207,210,211; pis. 26,27 

Ground-water leaching of scheelite....... 192-193-

History of area.. __ 183 

Johnson Creek...__... . 201

Little Eldorado Creek . .. ......... 210

Location of deposits.___... - 180; pi. 23-

Mertie, J. B., Jr., quoted 194,205,208 

Metals Reserve Company, Reconstruction

Finance Corporation........... 190,198

Minerals:

albite...--. 185,192

anorthoclase . . 191 

apatite.. 185,186,191,198,199,200 

axinite.--. _. ..__..__. ... . 191 

biotite. ....... ....... . 185,186,191,199

calcite 191,192,202

chlorite ........... ........ 191,199

cllnozoisite ............_..... 191,199,202

diopside...._...... ........ 187,191,199,202

epidote . 191,199

feldspar.-- . - 186 

alkali 185

soda-lime._________________ 185 

fluorite ......... ................ 202

garnet. _ ..... ... 186,187,191,199,202

hornblende 185,187,191,192,199,202 

ilmenite.__._............_..... . 186

limonite............................ 192,193,196

magnetite... -----_-__. ... 185,186

manganese oxides . 192 

meliphaiiite. _ 191 

mierocline___.... 186

muscovite ............ 185,186,191,199,200

oligoclase ............ 186,191,199,200

orthoclase.. ........................ 192,199

pyrite 192, 193

pyroxene.. _ .. _ 186

215
216 INDEX

Page

Minerals Continued

pyrrhotite ___ __________ 192

quartz.. . 185,186,191,192,194,198,199,200,202

glassy.- _....._________ 201

scheelite_.________________ 18U.

185, 187, 188, 189, 191, 192-193, 194-196,

199, 200, 201, 202, 203, 204, 205, 207, 208,

209,210.

sphene__..................... 186,191,192,199

titanite ............................. 186

vesuvianite___.__________ 187,191,202 

zircon.-.. ___._____.___._.. 186 

zoisite ...._.._______ 186,187

Mines:

Cleary Hill.................. 206,208-209; pi. 23

Johnson...._________________ 210

Mizpah_._._____........_._ 208-209

Rainbow__________________ 210 

Stepovich...___........._... 189,196; pi. 25

Tolovana_________________ 210 

Wackwitz 206-208

Moose Creek_________. ________ 206

Ore shoots, scheelite....... 194,195,196-197,199-200

201,207,208; pis. 25,26,27

Pearl Creek._........................ 186,188,211

Pedro Creek..._.____...__ 181,283 

Pedro Dome area:

description________.....__._. 206-211

location...._____________ 180; pi. 23

placer scheelite._____________ 188,210 

precipitation..____......___...._ 183

prospecting tor scheelite.- ________ 212 

rocks 185,186

structure.________________ 187 

Placer scheelite-__._._.......... 188,210-211

Prindle, Katz, and Smith, qnoted-..-..._ 185-186 

Prospecting, areas favorable for.______ 211-212 

Prospects:

Blossom...................... 201,203-205; pi. 28

-Columbia. __________ 201,205-206: pi. 28 

Egan................................... 206,210

Leslie......___.............__ 206,209-210

Schubert-______._._____._ 189,201 

Spruce Hen.._........ 201,202-203,204; pi. 28

Tanana . 201,204-205; pi. 28

Tungsten Hill...................... 201-202,205

Yellow Pnp__........_ 184,189,200-201; pi. 24

"Belief.._._.._....___________ 181

Hocks:

altered granitic intrusives______ 186; pi. 23 

amphibolite-........ 185,191-192,196,197; pi. 25

garnet tactite_______________ 199,200 

granodiorite..__...... 185-186,209,210; pi. 28

limestone _. 187,188,194,196,201,206,211-212 

crystalline-______________ 185, 

188,189-190,191,192,196,198,199,202,206, i 

209,210; pis. 23,25,26,27 

silicated...________ 199,201; pis. 25,26 |

Fasre

Rocks Continued

porphyritic granite. .... 185, 

186,187,188,189,191,199,201,202,203, 206, 

210,211,212; pi. 23.

quartzite..._.............. 185,206.209; pi. 26

schistose_____.__ 185

schist 185,209; pis. 25,26,27

amphibole .__.._ .. 203 

Birch Creek.. .. - 184-185,186-187 

calcareons......___._.. 187,188,199,206

carbonaceous.. .... 185

hornblende--.. ___ .. 185,202 

hornfelsicmica...___. .. 201 

mica..__________________ 205 

quartz __ .. 202 

quartz-biotite _.._-----_..... 203

quartz-mica..... . 185,189,202,206,209

qnartzite...___...... . .... 205,208

silicated...__.-__..______ 199 

silicated mica . 191,194,197

silicified .................. 191-192,196

Rose Creek-__________________ 188,211

Seattle Creek-__. . .. 209

Skoogy Creek...........___.._.___ 210

Smallwood Creek..___________ 181; pi. 23 

Sprnce Hen lode . ..... 188; pi. 28

Steele Creek . .. 181,188,201,202; pi. 23 

Steele Creek-First Chance Creek area:

description- . 201-206

location........- . . 180; pi. 23

placer scheelite--- .... . . 188,211

prospecting for scheelite.... . 212

structure.___ .. -. . 187 

Steele Creek'Valley. - - 205 

Steese Highway ..__ 180,183,188,201,210; pi. 23 

Stepovich lode. _... _.. _ 188,189-198; pis. 24-26 

Stringers. See Veinlets. 

Structure-__________ .. . 186-187,192

Tanana River._.....__ ... . 181,183,185 

Timberline ...........- . .... 183

Too Much Gold Creek................... 208; pi. 23

Topography....... . . .. 181-182

Tungsten Gulch -... 204,205; pi. 28 

Twin Creek..._. .. . 210

United States Smelting, Refining & Mining

Co...... 211

Vegetation....__-___.__ ...__. 182-183

Veinlets:

quart? . 192,203,204,209 

quartz-seheelite--. ........ 203,204,205,206

Veins:

gold quartz... 185,187,188,205,206,208,210 

gold-tungsten- . . .... .. 208 

quartz _ .. - 186,207,208 

pegmatitic....___.. 188,189,194; pi. 25 

Wyoming (vein 5) ... 207-208

Willow Creek.. ._........._........ 210

Yellow Pup Creek...__....._... 200; pis. 23,24 

Yukon Biver........... ....-..... 184-185
Mineral Resources 

of Alaska 

19544955

GEOLOGICAL SURVEY B-ULLETIN 1024

UNITED STATES GOVERNMENT PRINTING OFFICE, WASHINGTON : 1957
UNITED STATES DEPARTMENT OF THE INTERIOR 

FRED A. S EATON, Secretary

GEOLOGICAL SURVEY 

Thomas B. Nolan, Director
CONTENTS

[The letters in parentheses preceding the titles designate separately published chapters]

Page

 (A) Radioactivity investigations in the Cache Creek area, Yentna district, Alaska, 1945, by G. D. Robinson, Helmuth Wedow, Jr., and 

J. B. Lyons_______--__-__-_____---_---____-___-___-_---_____ 1

(B) Investigations for radioactive deposits in southeastern Alaska, by

Walter S. West and Paul D. Benson___________________________ 25

(C) Radioactivity investigations at Ear Mountain, Seward Peninsula,

Alaska, 1945, by P. L. Killeen and R. J. Ordway____________ 59

(D) Magnetite deposits at Tuxedni Bay, Alaska, by Arthur Grantz______ 95

(E) Pyrite deposits at Horseshoe Bay, Latouche Island, Alaska, by Francis

A. Stejer.__________________________________________________ 107

 (F) Tungsten deposits of the Hyder district, Alaska, by F. M. Byers,

Jr., and C. L. Sainsbury___-_^-___-_-____--_-._---__-__-------_ 123

(G) Geology of two areas of pegmatite deposits in southeastern Alaska, by

C. L. Sainsbury___--___-_-.-_____-_________-___-____-----__-_ 141

(H) A geochemical exploration for antimony in southeastern Alaska, by

C. L. Sainsbury__------------___----_._________________ 163

 (I) Tungsten deposits in the Fairbanks district, Alaska, by F. M. Byers,

Jr___--_-- --_- _- -_ -__ - _ 179