UNITED STATES DEPARTMENT OF THE INTERIOR 

Harold L. Ickes, Secretary

GEOLOGICAL SURVEY 

W. C. Mendenhall, Director

Bulletin 936-0

NICKEL-COPPER DEPOSIT

AT FUNTER BAY 

ADMIRALTY ISLAND, ALASKA

BY

JOHN C. REED

Strategic Minerals Investigations, 1942 

(Pages 349-361)

UNITED STATES

GOVERNMENT PRINTING OFFICE 

WASHINGTON : 1942

For sale by the Superintendent of Documents, Washington, D. C. -------- Price 15 cent*

CONTENTS

Page

Abstract................................................. 349

Introduction............................................. 349

Geology.................................................. 352

Structure............................................ 353

Nickel- and copper-bearing sill. ...................... <>. 354

Origin............................................... 355

Reserves............................................. 356

Size of the deposit.............................. 356

Tenor of the deposit............................. 358

Economic considerations.............................. 360

ILLUSTRATIONS

Page

Plate 51. Geologic map of the vicinity of Robert Barren

Peak, Admiralty Island, Alaska.............. 352

52. Geologic map and section of vicinity of outcrop of basic sill on Admiralty Island near 

Punter Bay, Alaska.......................... 356

Figure 41. Index map of southeastern Alaska showing the 

location of the nickel-copper deposit at 

Punter Bay, Admiralty Island................ 350

42. Map of tunnel in nickel-copper deposit on 

Admiralty Island near Punter Bay, Alaska, 

showing places where samples were cut....... 359

III

NICKEL-COPPER DEPOSIT AT FUNTER BAY, 

ADMIRALTY ISLAND, ALASKA

By John C. Reed

ABSTRACT

The nickel-copper deposit near the north end of Admiralty 

Island, about 18 miles in an airline west of Juneau, in southeastern Alaska, consists of a basic sill which averages somewhat 

more than 100 feet in thickness. The sill, which dips eastward, 

is intrusive into a thick sequence of phyllite and various types 

of schist.

The rock of the sill consists principally of the silicate 

minerals labradorite and olivine, but it also contains magnetite 

and the sulfldes pyrrhotite, pentlandite, and chalcopyrite. It 

assays, on the average, about 0.34 percent nickel and 0.35 copper, which are doubtless mostly in the pentlandite and chalcopyrite respectively but are probably constituents of other minerals also. A significant proportion of nickel and copper is 

probably contained in the olivine and perhaps in the pyrrhotite.

The incomplete data available indicate a reserve of approximately 560,000 tons. Further exploration would probably show 

that the quantity is rather greater than this; but the average 

grade would probably not prove higher than that indicated above, 

although some ore of relatively high grade might well be found 

in places.

Although mining conditions are generally good, the nickel 

and copper content of the rock is so low that it appears very 

doubtful whether the deposit can be exploited successfully or 

contribute significantly to the Nation's nickel supply. Any 

further study and development of the deposit should be directed 

toward determining its full extent and toward more complete 

knowledge of the amount, distribution, and availability of the 

nickel and copper in the rock and in each of its constituent 

minerals.

INTRODUCTION

The nickel-copper deposit, known as the Mertie Lode, described in this report is on the west side of Mansfield Peninsula 

(see pi. 51), which forms the northernmost projection of Admiralty Island, one of the large islands of the Alexander Archipelago of southeastern Alaska (fig. 41). The deposit is on

349 

4 5/12
350 STRATEGIC MINERALS INVESTIGATIONS, 1942

the northwestern slope of Robert Barron Peak, southeast of 

Punter Bay.

Punter Bay is about 18 miles in an airline west of Juneau 

on the mainland. It is readily accessible by boat, and a steamer

figure Ml.---Index map of southeastern Alaska showing the location of the 

nickel-copper deposit at Funter Bay, Admiralty Island.

lane passes close to its mouth, but the water distance from 

Juneau is about 55 miles. The bay is a well-protected harbor, 

much used by local fishing boats. In addition to several good
NICKEL-COPPER DEPOSIT AT PUNTER BAY, ALASKA 351

anchorages it has two docks, one at a cannery on the north side, 

where there is a post office, and another, which belongs to the 

owners of the Hertie Lode, on the southeast side.

A number of buildings, including cabins, a bunkhouse, a cookand mess-house, an assay office, and a mill have been constructed 

near the dock on the southeast side of the bay. Prom the mill 

a narrow-gauge railroad extends southeastward about three-fourths 

of a mile over bench land, in part swampy, to the foot of the 

steep slope of Robert Barren Peak at an altitude of about 200 

feet. Prom the southeast end of the railroad a long tunnel, 

driven in the search for gold deposits, extends southeastward 

into the mountain, and from a point nearby, two aerial tramways, 

now in disrepair, diverge from the railroad one southeastward 

to a gold prospect and the other eastward to the Mertie Lode.

The nickel-copper deposit lies below timber line at an altitude of about 1,700 feet. It is about a mile southeast of the 

dock and about half a mile east of the Junction of the tramways 

with the railroad, from which it is accessible by trail.

The Mertie Lode was discovered in 1919. It was named for 

J. B. Mertie, Jr., of the Geological Survey, who was one of the 

discoverers. It is on the War Eagle Extension No. 2 claim, 

which is one of a large group covering an extensive tract between 

Punter Bay and Hawk Inlet, which is farther southeast on the 

west coast of Admiralty Island. The War Eagle Extension No. 2 

claim is owned by the Admiralty-Alaska Gold Mining Co. W. S. 

Pekovich was in charge of the affairs of the company on the 

ground when the property was examined, but no mining or development work was then being carried on, and no ore has been shipped

from the lode. The deposit has since been examined for the

!/ 

Geological Survey by Buddington and by the author. Most of

the investigation on which this report is based was carried on 

during the field season of 1937, but much of that season was

I/ Buddiogton, A. F., Mineral resources of Alaska, 192U: U. S. Qeol. 

Survey Bull. 783, p. U6, 1926.
352 STRATEGIC MINERALS INVESTIGATIONS, 1942

spent in the study of the general geology and of the numerous 

quartz veins and prospects in the vicinity. The property was 

also briefly examined in the summer of 1936 and again In 1938.

Many company records were made available by W. S. Pekovlch, 

who also personally gave the author much pertinent information. 

Particular acknowledgment is due Rado Pekovich, who extended to 

the Survey party every facility of the camp at Punter Bay and 

accompanied the author on most of his trips to the nickel-copper 

deposit.

' GEOLOGY

The country around Punter Bay is underlain by a thick sequence of metamorphic rocks. The age of these rocks is not 

definitely known, but on a map compiled by Buddington and

§/ Chapin, they are designated as "Paleozoic sediments and volcanics." The sequence includes both sejaimentary and igneous 

rocks, the latter being partly extrusive and partly intrusive 

types. All these rocks have undergone intense dynamic and 

igneous metamorphism, by which their original characteristics 

have been largely obscured or obliterated.

On plate 51 the bedded rocks have been grouped into three 

units marble, greenstone, and phyllite. The oldest unit is the 

marble, which is light-colored and coarsely crystalline. It 

crops out only on and near the blunt promontory that projects 

into the bay west of the shore terminus of the railroad. Thephyllite includes black, graphitic phyllite, light-colored 

siliceous schist, and some greenstone schist. The greenstone, 

which is exceptionally albitic, Includes a great variety of 

greenstone schists, gneisses, and locally massive greenstones. 

Much of it was probably intrusive originally.

The phyllite and the greenstone are in part interbedded, 

and some layers of both are discontinuous. Much of the discon2j Buddington, A. F., and Chapin, Theodore, Geology and mineral deposits 

of southeastern Alaska: U. 3. Oeol. Survey Bull. 800, pi. 2, 1929.
UNITED STATES DEPARTMENT OF THE INTERIOR 

GEOLOGICAL SURVEY BULLETIN 936 PLATE 51

13 4° 5O'

EXPLANATION

UNCONSOUIDATED 

ROCKS

Glacial moraine

Phyllite Greenstone

(/nc/udes b/ack graph/tic (/nc/udes greenstone

phyl/ite, /ight-co/ored schist, schist, gneiss, and

and greenstone schist) massive greenstone)

Base modified from part of 

Geological Survey map of Admiralty Island

GEOLOGIC MAP OF THE VICINITY OF ROBERT BARRON PEAK,

ADMIRALTY ISLAND, ALASKA

o

i

iMile 

i

Contour interval 5OO feet 

Datum is mean sea level

Marble

Strike and dip of foliation showing 

direction and pitch of linear 

structure and fold axis
NICKEL-COPPER DEPOSIT AT FUNTER BAY, ALASKA 353

tlnulty appears to be due to structural movements, but it is 

doubtless due in part to differences in original discontinuities 

of the strata and of the intrusive bodies,

A basic sill and several dikes of widely varied composition 

were intruded into the metamorphic rocks after the metamorphism 

took place, being themselves unaffected by shearing or other 

drastic alteration. The relations of the dikes to the sill are 

unknown and being of no economic importance they will not be 

described and are not mapped. The sill, on the contrary, is of 

economic importance, for it constitutes the nickel-copper deposit 

which forms the main subject of this report. It is therefore 

described in some detail on pages 354-360 and its position ia 

shown as well as available data permit on plate 52. The bench 

land between Punter Bay and the foot of the mountain is largely 

covered with glacial moraine*

Structure

The principal structural feature of the area illustrated by 

plate 51 is an anticline, the axial plane of which strikes 

northwest. The anticline pitches southeast at a low angle, and 

is in general a relatively simple fold, but it is modified at 

many places, particularly near its axis, by a multitude of 

smaller plications, some of which are to be measured in fractions 

of an inch.

The metamorphic rocks are all foliated. At most places the 

foliation appears to follow closely the stratification, which, 

however, cannot everywhere be identified. Besides the foliation, 

the rocks are widely affected by a linear structure, which is 

apparently parallel to the axes of both the large anticline and 

the small folds.

The rocks are cut by many well-defined and continuous Joints, 

most of which trend northeastward and dip steeply to the northwest, nearly at right angles to the axis of the anticline.

480160 O - 42 - 2
354 STRATEGIC MINERALS INVESTIGATIONS, 1942 

NICKEL- AND COPPER-BEARING SILL

The nickel-copper deposit at Punter Bay is the basic sill 

mentioned on page 353. This sill crops out on the northeast 

limb of the anticline, not far from its axis; it strikes about 

N. 15° W. and dips about 38° E. It is in contact with rocks of 

the phyllite unit. It is about 138 feet thick at the outcrop 

but apparently thinner underground. The rock of the sill is 

nearly black, and for the most part coarse-grained, but it contains scattered finer-grained masses, the largest several inches 

across. It might be classified as a gabbro especially rich in 

ollvine and poor in pyroxene; its chief constituents are labradorite, olivine, and pyroxene, which are partly altered to sericite, carbonates, brown hornblende, serpentine, talc, biotite,

2/ and chlorite. The rock also contains the opaque minerals of

metallic luster, which will be referred to as metallic minerals 

magnetite (FegOg.FeO), pyrrhotite (PenSn+-L), chalcopyrite 

(CuFeS2), and pentlandite (sulfide of iron and nickel). Most of 

the copper and nickel is probably contained in the chalcopyrite 

and pentlandite, but significant quantities of both metals appear 

to be present in the ollvine. A few samples taken from the sill 

on the walls of a short tunnel contain, on the average, 0.34 

percent nickel and 0.35 percent copper.

The relative proportions of the constituent minerals differ 

widely from place to place, but on the average the exposed rook 

contains about 60 percent labradorite, 23 percent olivine, 2 

percent pyroxene, 12 percent secondary minerals, and less than 

2 percent metallic minerals. One specimen, collected to represent rock especially rich in sulfides, contains 29 percent 

labradorite, 30 percent olivine, 13 percent pyroxene, 10 percent 

alteration minerals and 18 percent, in all, of the metallic 

minerals.

i/ Reed, J. C., Nickel content of an Alaskan basic rock: U. S. Qeol. 

Survey Bull. S97-D, 1939.
NICKEL-COPPER DEPOSIT AT FOOTER BAY, ALASKA 355

Not only the aggregate volume of the metallic minerals but 

also the relative abundance of these minerals differs widely In 

different specimens of the rock. The range In the constitution 

of the metallic minerals In three polished sections of the rook 

Is Illustrated In the following table.

Volumetric percentage of each metallic mineral as compared with 

the total volume of metallic minerals in specimens from a sill 

on Admiralty Island

Polished section

1. .............

2..............

3..............

Average .....

Pyrrhotite

80.1

63.6

54.8

66.2

Magnetite

5.1

12.9

33.2

17.1

Chalcopyrite

9

C

15.9

8.8

11.4

Pentlandlte

5

0

7.5

3.2

5.3

Apparently not enough time has elapsed since the outcrop of 

the sill was glaciated to permit the formation of more than a 

very thin weathered zone, which may be either richer or poorer 

than the original rock in such metals as nickel and copper. 

Limonite has formed in the joints of this rock at least as far 

underground as the face of the tunnel (see fig. 42), and near 

the tunnel portal weathering has spread widely from the Joints, 

between which are boulderlike masses surrounded by weathered 

material. Fresh sulfide minerals can easily be exposed with a 

prospector's pick at many places over the outcrop of the sill.

The nickel-copper deposit is of magmatic origin. The basic 

magma from which the sill crystallized was probably differentiated at depth from a more silicic magma. The basic fraction 

apparently was then intruded into the already metamorphosed 

phylllte.

The sulflde minerals were among the latest in the sill to 

crystallize and consequently are now mostly interstitial to the
356 STRATEGIC MINERALS INVESTIGATIONS, 1942

silicate minerals. Residual fluids released when the rest of 

the sill consolidated probably account for the partial alteration 

of the earlier formed silicate minerals and may also have moved 

the sulfide minerals for short distances and in small quantity.

Reserves 

Size of the deposit

The whole sill is considered as the nickel-copper deposit. 

Further prospecting may indicate that this is too sweeping an 

assumption; some richer parts may eventually be considered workable and other parts be excluded as of too low grade.

Calculations based, on data and assumptions given below indicate that about 560,000 tons of material are available. The 

actual .tonnage may be much larger but is probably not smaller 

than the figure given.

The-total distance between the most northerly and the most 

souther.ly points of outcrop is about 84 feet and any greater extent, is concealed beneath talus. The sill is exposed throughout 

a tunnel about 110 feet long, and it has been searched by a number of diamond-drill holes, some of which are in the sill for 

part .of their lengths while others are not.

When the drill cores were examined in 1937, many of them 

were badly disarranged. The cores of holes F and H, which seemed 

to be still more or less intact, were logged and the logs are 

used In this report. But the reliance that might otherwise be 

placed in the data from the drill cores is tempered somewhat by 

thQ condition of the cores and records of holes other than F 

and H. Hole A could not be found on the groundj Its location, 

direction, dip, length, and the fact that it does not anywhere 

encounter the sill were all accepted as reported to the author. 

The core of hole D was not logged and its reported length In the 

sill, when plotted, gives a slightly different measure of the
UNITED STATES DEPARTMENT OF THE INTERIOR 

GEOLOGICAL SURVEY BULLETIN 936 PLATE 52

It. at end 

of hole A 

l,520'±

Hanging wall of sill 

accord ing to D.D.H. D

;--/V^7^-Vixf-o^ L r -i- -> . 1 \ t-ianging wail or , 

^/-S'gstSj - ' -7 " r - f\ \^ * Sill according to ,\\

EXPLANATION

Landslide of November 1936

(Nat distinguished from phyl/it

Unfoliated light-colored dike

Basic sill 

Fault

_L_3I

Strike and dip of 

foliation and bedding

0 D.D.H.f-is°> ,_

Diamond-drill hole showing 

direction and dip

(Dashed /irie shows projection or 

drill ho/e; solid line shows drill hole 

in plane of section)

All of area represented by this 

plate is shown as phyllite on pi.51

GEOLOGIC MAP AND SECTION OF VICINITY OF OUTCROP OF BASIC SILL 

ON ADMIRALTY ISLAND NEAR FUNTER BAY, ALASKA

100 o

1111

200 Feet

Contour interval 20 feet 

Datum is mean sea level
NICKEL-COPPER DEPOSIT AT PUNTER BAY, ALASKA 357

sill's thickness than is indicated by hole P (pi. 52). This 

difference depends on an apparent difference in the position of 

the hanging wall of the sill, but the position of the wall in 

hole D may have been wrongly reported. Hole P may have been 

drilled from a point within the tunnel and not from the portal 

as shown on plate 52.

At the surface, along the line of section A-A 1 , the sill is 

about 138 feet thick. At the tunnel portal, a few feet farther 

north, it is a little thinner. The core of hole H, about 175 

feet below the lowest point on the outcrop indicates that the 

sill at this level is a little less than 100 feet thick. Whether 

or not this indicates a general thinning with depth is not known.

Observations at the outcrop of the sill and in the metamorphic rocks above and below it along the creek show that there 

the sill strikes about N. 15° W. and dips about 38° E. Hole H 

indicates a considerably steeper general dip. In any case, if 

the sill extends northward with approximately the same strike 

and downward at any angle greater than about 40°, it should have 

been encountered in hole A. The fact that hole A is reported 

not to have encountered the sill indicates that the reported 

information on the hole is not correct, that the sill does not 

extend that far northward (approximately 140 feet from the line 

of section A-A')» or that the dip is less than 40° and much less 

than is indicated en plate 52. The last mentioned possibility 

is considered the most likely.

In order to estimate the possible tonnage of material available in the deposit to the level of hole H, it was assumed that 

the specific gravity of the average rock is 3 and that the sill 

continues with the same cross section area as is indicated on 

plate 52 for 100 feet north of the plane of section A-A 1 and for 

an equal distance south. If the sill actually terminates south 

of the line of hole A, then the assumption that it has the same 

cross section area for 100 feet northward is probably not
358 STRATEGIC MINERALS INVESTIGATIONS, 1942

justified; but any error introduced by such an assumption would 

probably be compensated for by material below the level of hole 

H.

Tenor of the deposit

The distribution of nickel and copper within the sill la 

not known. Assay results of samples that have been taken indicate considerable variation from place to place but the sill is 

not widely enough exposed either on the surface or underground, 

nor have enough samples been cut, to permit the working out of 

the pattern of distribution of these metals.

The following discussion on the grade of the deposit is based 

on the results of analyses of samples and specimens collected 

by the author. All the material collected came from the tunnel, 

and it is assumed that the rock there exposed is representative 

of the sill. This assumption is supported by the fact that the 

core material from hole H appears siinilar to that in the tunnel. 

That wide extrapolations of grade from the small amount of sample material collected in the tunnel must be made with great 

caution is shown by the range in grade of the samples collected 

and by the fact that similar deposits elsewhere commonly show 

similar variations.

In the table below are listed the results of the analyses 

of six samples that were.cut in the tunnel. The places i-n the

Percentages of copper and nickel in samples from sill 

on Admiralty Island near Punter Bay, Alaska 

[Analyst, R. C. Wells]

Nickel. ........................

1

0.26

.28

2

0.27

04.

3

0.36

 ZM

4

0.25

.25

5

0.61

.61

6

0.45

 zn

tunnel from which the samples came are shown on figure 42. 

Sample 1 consisted of chips collected about 8 inches apart along
NICKEL-COPPER DEPOSIT AT PUNTER BAY, ALASKA 359

the inner 28 feet of the tunnel. All of the others were channel 

samples, but the channels were neither as wide nor as deep as 

would be necessary for precise results. Sample 6 was cut from 

weathered material near the portal of the tunnel to find out if 

weathering had produced any notable differences in the amounts 

or proportions of copper and nickel present.

The average content of nickel and copper in the rock of the 

sill as exposed in the tunnel and as represented by the samples 

is, if sample 6 is omitted because it is of weathered material, 

0.34 percent and 0.35 percent respectively. The gross value of

N 

A

Simple I. Horizontal, 

ZSfeet long £u,0.26, Mi.i

i,O.Z4)

Sample 6- »*. w.^.., 

7 feet long(pu,o.4Sj M > ; NI,O.ZS)

100

i .

Sample3. Vertical 

7 feet long (Cu. 036; Hi, o>»)

100 Feet 

I

Figure Us. Uap of tunnel in nickel-copper deposit on Admiralty Island near 

Punter Bay, Alaska, showing places where samples were cut.

such material, at the assumed prices of 35 cents per pound for 

nickel and 12 cents per pound for copper, is $3.22 per ton.

The results of petrographic studies of a few specimens from

the nickel-copper deposit have been reported elsewhere in coni/ siderable detail. The chief practical result was that the study

did not reveal the presence of enough pentlandite and chalcopyrlte to account for the quantities of nickel and copper shown 

by chemical analyses. The divergences between the chemical and 

the petrographic results are so great that they can scarcely be 

accounted for by assuming that the few thin and polished sections studied microscopically do not correctly represent the 

much larger volumes of material represented by the samples

U_/ Heed, J. C. , op. cit.
360 STRATEGIC MINERALS INVESTIGATIONS, 1942

analyzed. It is therefore inferred that much of the nickel and 

copper is probably present in minerals other than pentlandite

and chalcopyrite. Nickel is an appreciable constituent of many

5/ 

olivines. Inasmuch as the deposit on Admiralty Island contains

about 23 percent (probably about 34 percent before some of the 

ollvine was altered) of olivine (p. 354), the ollvine may contain a considerable part of the nickel. Whether or not the 

iron sulfide pyrrhotite in this rock contains significant amounts 

of nickel or copper or both is not known.

Economic considerations

It seems unlikely that material such as that constituting 

the nickel-copper deposit on Admiralty Island can be profitably 

mined at present prices or can be counted on to make significant 

contributions to the Nation's nickel supply. The grade of the 

material is low and the apparent tonnage is small. Further 

development work, such as more diamond drilling, might greatly 

increase the estimated tonnage and, as the nickel and copper 

content of the sill is not yet adequately known, might possibly 

reveal significantly higher grade ore at some places in the sill. 

An Increase in the estimate of tenor, however, is thought to be 

much less likely than an increase in the estimate of size. If 

material such as that now known to be present should appear to 

warrant further investigation in the immediate or remote future, 

such investigation should include estimation of tonnages on a 

more precise basis than is now possible, the collecting of many 

samples in order to supply a more adequate knowledge of the 

amount and distribution of the nickel and copper content of the 

rock, and tests to determine what proportion of these metals 

would be recoverable by metallurgical processes.

$J Boss, C. 3., Shannon, Z. V., and Oonyer, 7. A., The origin of nickel 

silicates at Webster, N. C.: Scon. Geology, vol. 35, No. 5, pp. 528-552, 

1928.

Wells, B. C., Relative abundance of nickel in the earth's crust: 

U. 3. Oeol. Survey Prof. Paper 197 (in preparation).
NICKEL-COPPER DEPOSIT AT FUNTER BAY, ALASKA 361

In general, mining conditions in the vicinity of Punter Bay 

are good. The area is readily accessible by steamer; in normal 

times an adequate labor supply is assured by the proximity to 

Juneau; a sufficient supply of timber is locally available; the 

climate is not rigorous, although at the altitude of the deposit 

heavy winter snows are frequent; and the topographic position 

of the deposit favors cheap mining. No adequate water supply 

for power is available close to the deposit, but Diesel power 

should not be unduly expensive.

O