R. 1. 4358 OCTOBER 1948

UNITED STATES

DEPARTMENT OF THE INTERIOR

J. A. KRUG, SECRETARY

BUREAU OF MINES

JAMES BOYD, DIRECTOR

LIBRARY COPY

U. S. Bureau Minos

Boulder City, Nevada

REPORT OF INVESTIGATIONS

INVESTIGATION OF THE SALT CHUCK COPPER MINE

KASAAN PENINSULA, PRINCE OF WALES ISLAND

SOUTHEASTERN ALASKA

BY

S. P. HOLT, J. G. SHEPARD, R. L. THORNE,

I A. W. TOLONEN, AND E. L. FOSSE
R. I. 4358

0Ctober 1941.

PYPORT OF INTVSTIGATIONS

UNITED STI'1ff DTTPA? T OF TWE -INTRI JOR BUREAU OF MIEFS

IWVFSTIGATION OF THE MALT CBuC COPPER NINE, KASAANIU

PRINCE OF WA LESLAmD, SOTHSEA§lN, ALASK

-By S.P. Holt,2/ J. G. 5hepard,l/ R. L. Thorne,4/ By A. W. ToQonen,4/ and E. L. Fosse2/

* A.~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~

CON "ItWIS

Introduction and summawry . ................ ......... Acknowledgm±ents ............ . . *.,.,.,,,,,,, , 2

Location and accessibility ...b. ................. 2

Physical featurQe tnd climate .......................... 3 Hi-story and production . ................. ............ 3

Property and ownership . ........................ 4

Geology and ore deposits . ............................. 4

Sampling and analysis . . ................................ 8

Development . . O .. *............. ...... .... 10

Equipjinet . ................. ........... .11

Results of ore testing by the Bureau of Mnes .... 12

Mine ore ............... 12

Mill tailing .... ........................

INTEMOCI.TION AAl SD4EWY

The Salt Chuck mine is on the east bank of the Salt Chuck, a salt-water

inlet at the head of IKasaan Bay, Prince Edward Island., Southeastern Alaska.

The deposit -vwsa worked at intervals from 1905 until 1941. Early ship- ments of hand-sorted ore are reported to have assayed about 4 percent copper, 0.15 ounce gold, and 0.15 ounce silver. The total mine production up to 1941 is reported to have been 326,000 tons containing 6,200,000 pounds of copper.

During December 1942 the Bureau of Mines cut a 15-foot channel sanple on the-surface and 7 channel samples from headings on the 300-foot level.

In July 1943 a development project was starte&. Thirteen diamond-drill holes

totaling 1,550 linear feet were drilled from underground stations on the 200- foot and 300--foot levels.

1/ The Bureau of Mines will welcome reprinting of this paper, provided the

following footnote acknowledgment is used: "Reprinted from Bureau of Mines Report of Investigations 4358."

2/ Mining engineer, Rolla, Mo.

3;/ Senior mining engineer, Juneau, Alaska,

y,' Associate mining engrLneer, Juneau, Alaska.

5/ Assistant mining engineer, Juneau, Alaska.

2538
R. I. 4358

Sample analyses, drill-hole logs, and results of beneficiation tests are

presented in this report.

ACKNOWLEDGMENTS

Field investigations were under the general direction of P. S. Sarford,

acting chief, Alaska Branch, Mining Division. Preliminary examinations of

the deposit were made by the following members of the Bureau of Mines' staffR. L. Thorne, J. G. Shepard, and S. P. Holt. The investigative project of

the Bureau of Mines was supervised by S. P. Holt, assisted by A. W. Tolonen

and E. L. Fosse.

Special mention is made of the cooperation and assistance received from

John C. Reed, E. N. Goddard, H. B. Gault, Clyde Wahrhaftig, L. A. Warner, and

C. D. Bressler, members of the United States Geological Survey, who were

assigned to the area at various times during this project.

The many courtesies received from the owner, A. L. Howard, are also

acknowledged.

LOCATION AND'ACCESSIBILITY

The Salt Chuck mine is situatbd at 55° 38' north latitude, 1320 33' 30"

west longitude, on the east bank o'tfie Salt Chuck, a salt-water inlet at

the head of Kasaan Bay, .Prince of Wales Island, Southeastern Alaska. It is

10-1/2 miles northwest of the village of Kasaan, by Forest Service trail, and

43 miles northwest, by water, from Ketchikan. The general location is shown

on figure 1.

Kasaan has a store, a post office, an elementary school, and a cannery.

Except when the cannery is operating during the salmon-fishing season in July

and August, the community consists of fewer than 50 persons, mostly native

Indians.

Ketchikan, a city -of about 6,000 people, is a seaport on the-Inside

Passage waterway 750 miles north of Seattle and has regular steamer service

at frequent intervals supplied by the Alaska Steamship Co., Northland Transportation Co., Canadian Pacific Railway Co. Steamship Service, and Canadian

National Lines.

Ocean-freight rate quoted by steamship companies on ore or concentrate

from Ketchikan or Kasaan Bay to points on Puget Sound is $4.50 a ton plus

longshoring charges for loading and unloading. It is reported that marble

and limestone were shipped from Dall Island to Seattle for $0.90 a ton in

barges, an&ithat copper ore and concentrate were shipped from Salt Chuck to

Tacoma in small motor ships for $1.50 a ton, the ships bringing mill reagents,

grinding balls, mine supplies, and food on the return trips. To allow for

increased labor and other costs, the figure of $2.50 per ton for freight is

used for the purpose of estimates in this report.

Ketchikan is the best local source for food and mining supplies, lumber,

and labor.

2538 -2-
A A

/74 /62 /5 0' ZC '

SEWAR

mu~~~~~~I UL

- ^ '

/hel 0 ffel_/e 300 Em 7 1A

Figure 1. - Index map showing location of Salt Chuck copper mine.
R. I. 4358

PHYSICAL FEATURES AND CLIMATE

The ore deposit lies on a wooded knoll at 400 feet above sea level,

about 1/2 mile north of the mill and camp buildings, which are at sea level

along the shore of the Salt Chuck.- Surrounding terrain is low, covered with

dense underbrush,'-and partly wooded with spruce, hemlock, and a little cedar

suitable foQr mining purposes.

The climate is typical of southeastern Alaska, with mild temperatures, rarely dropping below 0° F. in winter or rising'above 900 F. in summer.

Precipitation is heavy, reported to average about 150 inches a year. Most

precipitation is in the form of rain, snowfall not often amounting to more

than 6 to 8 inches a year. During the winter of 1942, said to have been

unusually severe, 24 inches of snow was measured at an altitude of 400 feet

in December, and the temperature remained below 00 F. for 10-day periods.

Mining operations have been conducted at Salt Chuck throughout the year, with men properly -housed.. Shipping to end frrcn Seattle continues the year around by vessels moving along the ice-free -Inside Passage.

HISTORY AID PRODUCTION

The deposit, then known as the GoodroGor Joker prospect, was located in

1905 by Charles 'Goodro, who operated it at intervals from 1905 until 1915, shipping small quantities of ore during this period. This ore, sorted by hand, is reported to have contained 4 percent copper, 0.15 ounce gold, and

0.15 ounce silver a. ton..-- That the or.e contained palladium was not known at

that time.

J. A. Chilberg bought the property in 1915 and formed the Salt Chuck

Mining Co. A mill with a capacity of 30 tons of ore'a day was built, and an

adit tunnel 1,200 feet long at an altitude of 105 feet was driven to intersect

the ore body 300 feet below its outcrop. Capacity of' the mill was'increased

in 1923 to 130 tons a day.

In 1923 the company was reorganized by Mr' Chilbert under the name of

Alaska Palladium Mining' Co., 'and the capacity of th'e mill was again increased,

to 300 tons a day. This company suspended operations in 1926.

The property was then purchased at a marshall's sale by John Koel, of Ketchikan, and was optioned in 1929 to the Solar Development Co., a subsidiary

of Colsolidated Mining & Smelting Co. of' Canada, Ltd.

The Solar Development Co. diamond-drilled seven holes for a total length of 985 'feet from underground locations in the Salt Chuck mine. Results of

drilling was not encouraging and the company dropped its option in 1931.

,.Present owners of the property; the Alaska' Go~d'& Metals Co., operated the mine from 1934 to 1941, inclusive. From early 1941 to January 1946 it

has been idle.

2538 3
R. I. 4358

Total production of ore from this deposit from the beginning of mining

to the spring of 1941 has been, according to the unusually complete records

kept during the period:

Total tons ore-produced. ..... ..... -326,000

Total pounds copper produced .6,200,000

Average analysis of this ore was:

00.95 percent copper a ton.-

0.036 ounce gold a ton.

0.17 ounce silver a ton.

-0-063 ounce palladium a ton. .~~~~~~~~~~~~~~~

The latest operating company, Alaska Gold & Metals Co., reports the

following record of production from 1934 to 1941:

Ore mined . ......... . ........... ... . 80,000 tons

Smelter return ...... .......... 1,356,381 pounds copper

1,861 ounces gold

8,756 ounces silver

3,115 ounces palladium

Percent mill recovery ..... Copper, 85

Gold, 68

Silver, 72

Palladium, 65

Ratio of concentration .............. 45 to 1.

PROPERTY AND OlMERSHIP

The property consists of 23 lode-mining claims and two unpatented mill

sites. These claims were surveyed for patent in 1920 by H. P. Crowther,

U. S. DepuNty Mineral Surveyor, but patent proceedings were not carried to a

conclusion.

Th& Alaska-Gold & Metals Co., A, L. Howard, president, holds title to

the property subject to a mortgage held by John Koel of Ketchikanj Alaska.

GEOLOGY AND ORE DEPOSITS

The geology and ore deposits at the Salt Chuck mine have been described

by Gault,./ of -the Federal Geological. Survey, as follows:

The ore deposits are in pyroxenite and gabbro, which form part

of a large body of intrusive rocks at the head of Kasaan Bay.* * *.

The pyroxenite and gabbro are large irregular masses** *.

6/ Gault, H. Richard. The Salt Chuck Copper-Palladium Mine, Prince of Wales

Island Southeastern Alaska: U. S. Geol. Surv. mimeographed report,

1945, 68 pp.

2538 - 4
R. I. 4358

In the mine and the area immediately adjacent to it, the

upper surface of the gabbro forms a steep southeast-pitching

trough, which is filled with pyroxenite. The walls of the trough

are nearly vertical and in places are overturned. Fingers and

lobes of gabbro jut into pyroxenite, and pyroxenite lobes jut into

gabbro. Such projections of pyroxenite and gabbro are more abundant, and the trough is narrower away from its bottom in the

southern part of the ground opened by the mine near the start of

the 311 drift. In this part of the mine gabbroic pyroxenite rock

and alternating zones of gabbro and pyroxenite 1 foot to 5 feet

thick occur between massive pyroxenite and massive gabbro so that

the location of the boundary *** is approximate. In general,

elsewhere in the mine the boundary between gabbro and pyroxenite

is placed within a zone not more than 1 foot wide.

The portal of the 300 level tunnel is in gabbro. At about

40 feet in from the portal pyroxenite is exposed, and the 300

drift continues in pyroxenite for 620 feet to a point where

gabbro is again exposed. This gabbro is part of the same gabbro

body as that at the southern limit of the 300 drift **

North of the glory hole, across a muskeg area ** *, is a

group of knolls and hills underlain by greenstone. Greenstone

also crops out near the north and east sides of the lake east of

the glory hole. The contact of the greenstone and gabbro is

concealed.

Small: fine-grained basaltic dikes and thin, light-colored

dikes, possibly aplite, cut the other rocks. Basic dikes are

exposed in the western part of the mine at intervals from the

surface to the 300 level. These may be parts of a single dike.

The pyroxenite is dark-green and coarse-grained and contains

a pyroxene, probably augite, as the principal constituent. The

pyroxenite also contains minor amounts of feldspar. Magnetite

is a common accessory mineral, locally making up almost 10 percent

of the rock. Chlorite and epidote are common alteration minerals

in the pyroxenite. The typical gabbro is dark-gray and coarsegrained, containing feldspar and pyroxene in about equal proportions. The gabbroic pyroxenite contains more feldspar than

the normal pyroxenite but less than the typical gabbro. South

and west of the glory hole the gabbro apparently grades into a

lighter and finer-grained rock, which for the purpose of mapping

is called diorite** *. An altered gabbro, lighter-colored than

the typical gabbro and containing appreciable amounts of pyrite, is

exposed in the northern 140 feet of the 300 drift, at the north end

of the north drift on the 200 level, and in several drill holes * *

The greenstone is a fine-grained dark-green or brown rock

locally containing phenocrysts of augite and fragments of porphyry.

Throughout the mine and vicinity are bodies of altered pyroxenite

and gabbro, and gabbro and pyroxenite pegmatite.

2538 5
R. I. 4358

Many faults with small displacements can be traced through

the mine. Some of these faults are 4 inches to 24 inches thick

and in-the area of..the mine workings contain considerable carbonate

and chalc-opyrite in-:addition to fault gouge.

These faults appear to fan out northwestward from the narrow

part of the pyroxenite body, which fills the gabbro trough in the

vicinity of the south end of the main workings. Other small'faults

and many fractures are present throughout the mine, and some contain carbonate-veins, aplite, or very thin basic dikes. All faults

that cut the.gabbro-pyroxenite contact displace it for short

distances.

The gabbro and pyroxenite appear to be almost contemporaneous

differentiates of the same magma. The gabbro is considered to be

slightly younger and to have intruded the pyroxenite.

The principal ore mineral at the Salt Chuck mine is bornite.

Small amounts-of-chalcopyrite are locally associated with the

bornite. Chalcopyrite is the principal sulfide mineral in the

mineralized fault zones., Small flakes of native copper are

widespread throughout the mines but are too few to be economically

important. Chalcocite and covellite have been reported as alteration products,* * * and copper carbonates stain some weathered

surfaces and fractures. Ass-ocistea with the copper sulfides are

recoverable amounts of gold, silver, and palladium as well as a

little platinum. .

Pyroxenite ore and gabbro ore are recognized. In the highergrade pyroxenite ore the rock is cut by many small fractures

extending in all directions, some of which are slickensided but

show little displacement. The bornite is irregularly distributed

as disseminated grains and patches along the fractures and in the

rock between the fractures. In the lower-grade pyroxenite ore the

rock is more massive and the bornite commonly occurs on fracture

surfaces without penetrating far into the pyroxenite.

The.gabbro ore is generally of lower grade than the pyroxenite

oreand the.sulfido minerals are finer grained and more-uniformly

distributed through it. The gabbro ore is less fractured than the

pyroxenite ore, and the sulfide minerals are not restricted to

fracture surfaces.

The drill holes and the mine exposures indicate that the

bornite within the ore bodies is very irregularly distributed. The

ore is in small, shoots randomly arranged in the ore bodies with lean

and barren rock between them.

* The glory holes and&stopes*** probably represent the general

positions and shapes of the ore bodies which have been mined. In

detail the ore bodies probably were smaller than these openings

suggest and contained ore shoots and barren zones. Several small

patches of ore in stope walls and small pillars represent remnants

of these shoots. . -

2538 -6-
R. I. 4358

The ore bodies were more or less pod-shaped, generally with

their longest dimensions pitching steeply southeastward. The ore

bodies are smaller and more irregular in the southern part of the

main workings. -Descriptions of the ore which has been mined suggest

that the ore was richest near the center of each shoot.

The gabbro that crops out northwest of glory hole No. 1 ***

contains disseminated bornite and some chalcopyrite and is known as

the north ore body. The ore is leaner toward the edges of the

outcrop, and barren gabbro is exposed in the ore chute connecting

the north ore body with the 200 level.

Low-grade ore is exposed in portions of the raise leading to

the surface between the north ore body and the glory hole from the

200 level. The downward continuation of the gabbro of the north

ore body is exposed in the north drift of the 200 level. Bornite

occurs as scattered grains in the otherwise typical gabbro and in

gabbro containing disseminated pyrite only near their contact at

the north end of this drift. Normal gabbro and gabbro containing

pyrite are also exposed in the northern part of the 300 drift

below the north ore body but no bornite is recognized there.

These exposures on the 200 and 300 levels suggest that the north

ore body extends only to about the 200 level.

The ore exposed between the 300, 313, and 314 drifts * *

here called the middle ore body, apparently is the continuation

of the ore mined from stopes No. 3 and No. 4.

The gabbro ore in the southeast or 311 drift just east of

the pyroxenite-gabbro contact * * designated as the southeast

ore body, appeases to be the continuation of the gabbro ore

exposed on the south side of the 308 stope.

At the southwest end of the glory hole * * *, in parts of

the No. 1 stope and in a raise in the roof of the 201 stope at

its west end, bornite is disseminated through the gabbro. The

pyroxenite at the upper end of the ore chute connecting the west

end of the 201 stope with the No. 1 stope ** * also contains

scattered bornite grains. These bornite occurrences are near the

contact and may represent lean portions of the ore body mined out

in the western part of the 201 stope.

The deposition of bornite in the ore bodies apparently was

controlled by the gabbro-pyroxenite boundary and by fractures and

faults in the steeply pitching, pyroxenite-filled gabbro trough.

The pyroxenite in-the mine and immediate vicinity may represent

a local center of differentiation. The bornite was deposited from

rising thermal fluids, which presumably were differentiates of the

same parent magma. The bornite was deposited in the pyroxenite

after it was fractured.

2538 -7-
R. I. 4358

The ore-bearing fluids followed the contact and spread into

the fractured pyroxenite and into less-fractured gabbro. The more

prominent fault zones, which are now metallized principally with

chalcopyrite, seem.to have been the main channels for the dispersion

of thecopper-bearing fluids to the smaller faults and fractures and

thence to the microscopic fractures reported by Mertie * * *. The

ore shoots are not bounded bar the main fault zones but instead seem

to lie near them.

SAMPLING AND ANALYSIS

During 1930, the Solar Development Co., while it held the property under

lease and option, drilled 7 diamond-driU holes with a total length of 988.5

feet. These are shown on figure 4 and' table 1.

TABLE 1..- Sample analysee,,Salt Chuck mine

- - I . _ .. . .l ... ,Length 

Sample, of sample, Cu, Au, Ag, Pt group,

No. Location Ore body feet perdent oz/ton oz/ton oz/ton

BT/ Surface North 15 -1.25 0.01 0.15

B- S / .300 level Southeast 10 trace 0.01 0.10 :none

B-2 do. do. 10 0.33 0.015 0.12 none

B-3 do. do. 10 o.56 0.015 0.14 . 0.015

B-4 do. do. 10 o.84 0.01 0.10 0.03

B-5 do Middle 6 2.31 0.15 0.93 0.11

B-6 do. do. 15 0.30. 0.01 0.10 trace

B_7 do. do. 6 0.64 0.05 0.25 0.05

B-8 Mill heads - 0.77 0.02 0.18 0.015

B-9 Concentra.tes . 35.45 o.88 5.64 1.22

B-10 Tailings ' 0.13 0.01 0.11 1trace

S-13/ Hole S.D. 2 Middle 3 0.24 trace trace

S-2 do. do.. 5 1.14 0.03 0.25

S-3 do. d. o. 5 0.39 0.02 0.12

S-4 do. do. 5 nil trace tiace

S5_ do. do. 5 o.49 trace 0.12

s-6 do. do. 5 0.90 0.04 0.24

S -7 do. 'do. 5 9.28 trace trace

S-8 Hole S.D.. 2 Mi ddle 1 5.50 0. 1. 30

S-9 do. do. 0.5 1.04 0.04 o.48

S-10 do. do. 5 1.02 trace 0.10

S -11 do. do. 5 0.22 trace 0.10

S-12 do. do. 5 0.79 trace 0.20.

S-13 *do. do. 2.5 0.60 0.01 0.17

S-14 . Hole S.D. 3 do 5 0.32 trace trace

S-15 do. do. 5 0.38 I trace 0.'10

S-16 Hole S.D. 4 Northwest 5 none t trace

S-17 Hole S.D. 5 Middle 5 trace trace, trace

S-18 Hole S.D. 6 East gabbro 5 none Itrace, trace

See footnotes on page 9.

2538 -8
North Ore 8ody-'

*03

' .. I'..~~~~~~~~~~.......

'.,,* Oi;S,

50003i N.

1^.x,^ Pyrox en9-fe

g3~< Gab bra con 7Le7/,z7,,7

o/^ ro'z'o"0e borni7'e

* ~~~~~~~On

S Gabbro Orc

I' Fsoc@,>v

t0 .~~~~~~~~Sco7/e irl f eef

Per cen f Copp>Cer

H fi7. G'/0 6eo/ogic !ol Sw- vey

Figure 2. - Glory hole and north ore body.
/ ~~~~~~~~N

4\ .4 .~

- US 13

/ /~~~~~~~~~~~~~~00/

-'~~~~~~AI

L EOE-IVD

pyr ox /'I' c * 

O Bo~en rock

@Coffer- Ore zvfopeo

E[I 8,75rc all e 4

IJCholcoo yr7cc- r 2?0 0 .20 40 60 80

so, ,'t72/f ~~~~~~~~~5cale on? f eey

Oleolo9o n ^rpeatb; o fe

H.rC7 6 G eo/ogr7 S.Ur VeY.

Figure 3. - 200 level, Salt Chuck mine.
vSD4 .'4^

+^> 4 F9 ~~~~~~~~~~~~~OobbyrO

\\i -_ OJ Gebbro F containing d~ micnatet borite

\\ - GZJ~~~~~~~~~~E Pywoen jhc contvinin9 O.5ed oricf tio,- on Lane of H/ole S a 2 'a'~~~~~~~~~~~~E 00bbreCOnteI71Wnin5>diny~ritc ^/e-3o;eSj;

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~a o'6\ X , / ,/ ~~~~~~~~C-omate it nferred *d I

.~awcent copper- tis a...

Figure, - 3 - 04. 

O'/~~~~~~~~~~~~~~~~~~~~i youd 0~~~~~~~~~~~~~~~~~~~~~~Gbr SD-~ o aigdseiae onf 

'US 4~~~~~~~~~~~~Prxnfecnan, iMwfdoig .efo- o ~eo ocS0 us~~~~~~~~~~~~~~~~~~mObr onann isweprf

Oi 0~~~~

SD 6,~~~~~~~~.S

0 /0 oooSQ

o 50a iOO

Note: Oeologic11inferprefofion offer

HROuI eologi~cal 5urvey

Figure 4t.- 300 level, Salt Chuck mine.
N

KATZ k L EGEND

As z( Blis 1to5 G6oh61o wFhol-,IfYe

I d, inze

//\t fw~yl-oxenl'Yc

20 /O 0 20o 40

6eolog/lc / erftinby Clya:;4 Wah,-haygf is 6eolo /cal Suor vey

Figure 5. - Lower adit west of Salt Chuck mine.
/Vor/h Ore c

-Y

A~~~~~e v.200A NO E&v.Y

N' ,. d4~~~~A. \N~ oleV A

d /00 ::~~300 Leal I? A

B rokJen ro ck

3 GobbrU ore

Pyroxenife Ore

/ Con*.,7'f Inferred

A42 /%r-cen,' Copper

20 0 20 40 60 80

-~~~~~~~-/e ~ ~ k~ ~ v. O O ~ c/ f 

Figure 6. - Section on line of holes U.S. 5 and 13.
/V. /00 LI ~ A proX/zmafc Or,9Oa Su --

4r 

A~~ AAA

A~~~~~~~~~~

A~~~~~~~~~~~

A~~~~~~~~~~~~

Oa/ | A 2 0 0

A Level

t""'-~~~~A / A//

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. >, ~~~~~300Level/ aay/ A / / Ele v /O0

9\%\ 5/ev/o~~~~~~~ffiP~e 20

A~~~~~~~Co

* 66

L E-G~ L-~E ,IIii

E fyr-oxenie o so U 00007

@ O rAe 0 0r 0

\~~~~~~~~~~c/ Ie 7 & r7 

O ,)\7 /ec enfC opp er

Figure 7. Section on line of hole U.S. 6.
-'<----- NV. 690 ° /

Sea A A A A. eve/ * A AA'A;)A

A , .,Elev. ,00 A. A A-A AA Al'A. As\,

A AA aA & -,a , A r\ S

A/A A A A A' "A A'_

/~~~~~~~~A 9 'a,:C A r -- ~~A

[I~~~~~~~~A Aso ADikeVy

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Figure h U.S Af A.

A4~~~~~

a A

-5e I F''rA-rveeOr f~~§jj~~~ broIA OrAeAGab 

~~ 8c.~~s,~~/JkAeA A040 

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if 7ev/CO 300OLe *~~~~ ~ ~e~~~ S *I / - 6 t/ /.X -

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A A ~ ~ ~ ~~j

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A *6 ~~~~~~~~

A £ ~ ~~ ~ ~ ~ A

[I 6 o4'6 ro Ore

,. Con/-oc* inferredst ......... ;0A

E7 Pcsn Co', c L&

rc CoppeSclerir fe

Figure 9. - Section on l ine of hole U.S.,9.
-,2* 3 SD5$.-.; ., Se5a Level

.~~~~~~~~~S7Y \ 'E.- -

/ EG E/1iD

Y,- \N / 0,re/ , A

ES7 Gbbr-o

M Ga66ro Or-e

Confac Inferred f 5c > a/e on7A' feaFigure 10. - Section on line of hole U.S. 10.
use

AAA

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0A4 USA~~~

DA D

/~~~~~~~~~AA aa/\

44 ~A"a

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Figure 1

P A

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0 80

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A~~~

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_ _020004//eIve/ _ _

/ee~~~~~ 20 1 - ~/ s/j 

_~~~~A\ / ,37 i

~~ ~ ~ ~ DA P A Af-l D D\\\\\T A' - ___ DA^ .

usre 300 /00

G/V a 4 4t p ^N4 U /^ A 4 o /°D 5 A A A

ScOae /bb f e/e Y

Figure 12. - Sect ion on I ine of hole U.S. 1.
NJ4- / ,30 W

Nlorfh Ore 83ody

A A4~~~~

. >- , -,F ,, o ;o- t A. A -

E7/ev.o 200 a

A ~ ~ ~ ~ j

4 ~ ~~ ~ ~ ~ 4

A,~~~~~~~~~~~~~~~~~~~~~~~

'",-'I I, \l

14 AA

ff/ev~~~ /00 - -~~- ~~.- ~~ ,N AA~ A ~ ' S

EZGcwbro

E1^A Py r0 ox ifL

E1Gobbro conf a"7,t7

dsjse'rnoneYedoyr' ~e

ISL Oahbro COflanfl/7.

C hu7/c poyr,#fe vSeiin

W Baosic dik e

,'* Confc (nferred

PZ erce'n/ Coppoer

20 0 20 4-0 60 80

Scale in7 f ewe

Figure 13. - Section on 1ine of hole U.S. 12.
R. I. 4358

TABLE 1. - Sample analyses, Salt Chuck mine:(continued)

Length - -

Sample of sample, Cu Au, Ag, Pt group, No. SNo. HoleaStD.o1 Location Ore body dy____9 ____ ___ feet percent oz/ton az/ton oz/ton

S-l9 Hole S.D. 6 7past pyrox. 5 tracej trace trace

S-20 do. do. 5 trace trace trace

CcMPosite Hole US 5 20-45 25 1.15 trace 0.20 0.013 ._ Hole US 1 50-55 5 0.15 0.005 0.09 0.015 _ Hole US 3 35-40 5 0.18 trace 0.09 0.018

Do. Hole US 4 25-45 20 0.65 0.035 0.61 4/0.052

Do. Hole US 6 5-35 30 0.86 0.025 0.46 none

Do. Hole US 8 90-95- 10 2.28 0.040 0.41 4/none

105-1lQ

Do. Hole US 9 5-20 15 1.26 0.020 0.03 0.013

Do. Hole US 10 0-35 35 O.j6 0.005 0.62 trace

Do. Hole US 10 35-75 40 0.18 trace 0.05 0.005

Do. Hole US 11 35-70 35 0.07 trace . 0.04 0.015

Do. - Hole US 11 150-175 25 1.39 0.050 0.20 -/none

Do. fole US 12 50-65 15 0.23 none none none

Do. Hole US 12 70-110 40 0.28 none none none

Do. Hole US 12 110-150 40 0-33 trace 0.13 none

Do. Ho-le US .12 150-170 220 |0.25 none trace trace

Do. Hole US 13 4-6 .56. 1 0.43 0.010 0.03 none

Do. Hole US .13.1 65-100 35 | 0.91 0.010 0.19' -none

Do. JHole US 13 125-140 15 ' trace 0.25 none

1/ Sample taken by R. L' Thorn6, Bureau of Mines, 1942.

2/ Samples B-1 to B-10 taken by Bureau of- Mines, 1942.

3/ S-1 to S-20,-analytical results of samples from Sol1⁄2 -Development CO.'

diamond drill cores, 1930.

4/ Palladium indicated.

A sample was taken in August 1942 by an engineer of the Bureau of Mines

across 15 feet of the north (gabbro) ore body at the surface. In December

1942 the Bureau of Mines cut 7 channel samples on the 300 level, at the same

time taking a general mill-head sample from ore in mill bins, a sample from

concentrate sacked in storage, and-a general sample from the tailing pond.

The analyses of these samples. are shown in table 1.

-In June and July 1943, the Bureau of Mines diamond drilled 13 holes with

a total length of 1,553.5 feet frcm underground stations on the 200 and 300

levels of the Salt Chuck mine. Results of the drilling are shown graphically

on figures 3 to 13, inclusive.

Sludge from core drilling was carefully collected, dried, and split.

Sludge samples were analyzed by the Territorial Assay.Office at Ketchikan,

Alaska. Cores were split and analyzed by a private concern in the States.,

The analyses for copper of sludge and core samples from holes drilled

by the'Bureau of Mines were adjusted by the Longyear method, and the results

2538 . 9
R. I. 4358

are shown on figures 3 to 13. Method of adjustment, if any, of analyses

shown for solar development (S.D.) holes is not known. It is probable that

the results shown f o'r' thos-6'holes are' of cores only.

Cores from Bureau of Mines drill holes were composited, and composite

-samples 'wr'e'.analyzed for coppei', gold, silver, and platin-um group metals.

The results are shown in table 1.

The so-called "North ore body" was sampled by means of channel samples

cut 2 by 4 inches in cross section. Twenty-three samples with a total length

of 222 feet were cut from the outcrop of this deposit. The results of

analyses of these samples aBre shown on figure 2.

Two short adits 1,400 feet southwest of the glory hole have been driven

to develop an outcrop of gabbro containing disseminated bornite. Four

channel samples 2 by 4 inches in cross section, with a total length of 34

feet, were cut along the east wall of the lower of these adits. The results

of analyses of these samples are shown on'figure 5.

Average analyses of the three ore bodies and weighted average of all

ore is as followsAverageanalyses of all ore bodies

ICopper, Gold, Silver, Platinum group,

Ore body ~percent oz/ton oz/ton QZ/ton

North . ... . * ....... 0.452 0.01 0.08 o.02

Middle . .......... ......... : 0.946 0.024 0'.269 Ol5

Southeast ................. .. 043 0.025 0.130 0.005

Weighted average all ore r 61 -- 0.0141 0.017

Because of the low content of platinum-group metals in the. samples

analyzed, accurate determinations could not be made of the relative percentages of palladium and platinum, but previous experience of the operating

company, as given by A. L. Howard, manager, wag that the palladium-platinum

ratio iLn the ore was generally about 10 to 1.7

DiEELOPMENT

An adit 1,225 feet lbng taps the mine workings on the 300-foot level.

Drifts have been.driven on this level beyond the mined section, both to the

southeast and the northwest. Spiral raises wind up through large stopes

into the glory hole at the surface. Mining has left only remnants of the

100- and 200-foot levels. No workings extend below the 300-foot level.

From the initial operation until the property was taken over by the

Alaska Gold & Metals.Co., mining was confined principally to.the glory hole.

As large horses of waste occur within the ore shoots, the method resulted in

serious dilution of the ore, Shrinkage stoping has been carried on from the

sill of the 300-foot up to the 200-foot level. This method was much better

7/ Howard, A,. L, -The Salt'Chuck Mine,6, K'a taanBay, Prince 'of- Wales Island,

Alaska: Unpublished report, Jan. 7, 1935.

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R. I. 4358

than the old glory hole, as pillars of waste could be left in place. Walls

and roof stood remarkably well, and no timber was needed. The empty stopes

are still in good condition and can be traversed readily. In late years all

ore, which breaks rather blockily, was pulled from the stopes over grizzlies

and transferred by.chute raises to the 300-foot level, where it was drawn

and trammed to the mill. Owing to the nature of the ground and the relatively

large size of the ore shoots, mining costs were comparatively low.

Workings are in-fair to good condition. Track and air lines on 300 level

were repaired where necessary and used during the core-drilling program of'

the Bureau of Mines in July 1943. The air line to the 200 level was also

repaired and used at that time.

Timbering, mostly around chutes and raises, was nearly all standing in

July 1943 but would have to be replaced before the mine could be operated

again.

The rock is hard and stands well, so that very little timbering is

needed to support ground. Several faults, generally small, with 4 to 24

inches of gouge, were noted in.the glory hole and( stopes. A larger fault at

the end of the west drift on the 300 level strikes easterly and is probably

the same as that cut by the 300 main adit at the collar of drill hole SD 2

and in drill hole US 11. This fault has 10 feet of gouge and breccia, but

the ground is firm and requires no timbering.

The mine is wet, water coming mostly from the heavy rainfall, which

seeps down from the glory hole and other workings open to surface. No large,

open watercourses were noted in the mine, and only'a small' amount of water

flows from drill holes. Trouble from water is not to be expected if'winzes

are sunk short distances below the 300 level, although pumps will haveato be

provided to take care of normal.flows.

EQUIPMENT

Power-plant equipment consists 'of 5 semi-Diesel and full-Diesel engines

having a total capacity of 635 horsepower. 0f this total, 22C horsepower is

electrically connected, and. the remainder is belted to ball mills and flotation units. A Pelton wheel driven by water from Goodro Lake under 180-foot

head develops 60 horsepower for about 9 months each year.

Diesel-oil storage is provided-by four steel tanks with a total capacity

16,000 gallons. There are two air compressors, one a single-stage, class

E. R. 1, 14 by 12 inches, the other a converted steam compressor of similar

size and type. Both have been belted to Pleton wheels, and one of them is

so set that it can, by changing the belt, be driven by an electric motor.

Ore'was transported from the 300 level of the mine and over 1,200 feet

of surface tram in 40-cubic-foot, gable-bottom, side-dumping ore cars, of

which there are 11 on the property, besides a number of smaller cars.

Haulage was by a Mancha storage-battery locomotive of 4-1/2 tons capacity.

2538
R. I. 4358

A blacksmith shop near the portal of the 300-level adit contains a

forge, drill sharpener, and all necessary hand tools. Drifter, stoper, and

jackhammer drills, though in fair to good-condition, are most obsolete types.

Other shop equipment, including a blacksmith forge, lathe, and drill

press, are set up in the mill building.

'There is a small but well-equipped assay office. Sample crusher and

pulverizer are set up in the mill. Much of the assay equipment, especially

the furnaces and glassware, are now in poor condition. Milling equipment

includes:

1 7-foot by 36-inch Hardinge ball mill',

1 8-foot by 48-inch Hardinge ball mill.

3 Wilfley sand pumps.

2 3-inch Krogh sand pumps.

1 4-inch Krogh sand pump.

6 K. & K. flotation machines.

1 15-foot by 7-foot Dorr thickener.

1 9- by 15-inch Blake-type jaw crusher. -- 1 Symons disc crusher.

1 14- by 55-inch Traylor gyratory crusher.

3 Allen sand cones..

Conveying, feeding, and screening equipment.

Mill buildings, in fair condition, adequate

to house above equipment.

Most of the power-plant and mill machinery is in fair to good condition, except such articles as rubber hose and belting, which must be replaced

before mill Qperation is possible. The Blake crusher is broken and too small

for the job. The flotation machines are obsolete. A new Britannia-type

deep-column flotation machine, nearly completed' was intended to replace the

three old K. & K. machines.

Camp buildings include cook house, several dwellings, superintendent's

residence, office building, warehouse, and about 15 cabins. Nearly all of

these buildings are usable'but require extensive repairs,

RESULTS OF ORE TESTING BY THE BUREAU OF MINES

During the investigation of the Salt Chuck mine herein reported, it

became apparent that additional information on the factors controlling

successful concentration of the ore to marketable products was desirable.

Accordingly, one sample of mine ore and four samples of mill tailing wereobtained and. shipped to the Bureau of Mines' laboratory at Rolla, Mo.

for testing.

Mine Ore

The mine ore consisted of magnetite, bornite, sparing amounts of

chalcopyrite and malachite, and a very snall amount of pyrite in a pyroxenite

gangue.

2538 -12-
R. I. 4358

The bornite and chalcopyrite were fairly well liberated by 48-mesh

grinding. Considerable m~agnetite was locked at 65-mesh and some at 100-mesh,

but very little remained locked at 150-mesh.

The pyroxenite gangue of the mine ore and mill tailing consisted of

augite, talc, biotite, epidote, calcite, and fine veinlets of quartz.

Vanadium, which was detected chemically in both the mine ore and the

mill tailing, was concentrated in the magnetite, but the vanadium mineral

was not identified..

Analysis of the mine ore sample is 0.68 percent Cu, 8.6 percent Fe, and

0.06 percent V2%0.

No gold, platinum, or palladium was detected spectroscopically in the

samples, but a trace of silver was found. Fire-assay fusions were made on

the mine ore and later on th. composite mill tailing. Silver. was inquarted

in the charges, but the gold was not determined.. The dore beads were analyzed

spectrographically; a trace of platinum and a high palladium content were

noted. The spectrographic analysis, however, does not indicate a high amount

of palladium, as it was, not noted in a speotrographic Analysis of the ore

or tailing.

The treatment procedure involved tests on the flotation of the copper

minerals and magnetic separation of the iron minerals.

A portion of the ore was crushed to minus 10-mesh in a jaw crusher and

rolls. A charge of minus 10-mesh ore was stage-ground. in a pebble mill to

minus 80-mesh. The pulp density was adjusted to 25 percent with grind water,

and the charge was conditioned and floated in a mechanical-type, subaerated

flotation cell. The rougher concentrate was cleaned twice. Zeolite-softened

water was used for grinding and flotation.

The flotation tailing was treated in a Davis tube to remove the magnetite.

One ampere of current for a 15-minute period was used. The combined results

of flotation and magnetic separation were as followsFlotation and magnetic-separation results

Percent of

Weight, Analysis, percenttotal

Product Dercent Cu F VP09 Insol. P S Cu Fe

Copper concentrate. 1.21 45.71 9.3 1/o.os5 .83.8 1.3

Copper middling .... 2.44 179 8.8 /0.5 6.6 2.6

Copper tailing

Magnetic portion .. 8.50 0.02 61.7 0.52 9.4 0.036 0.03 0.3 62.6

Nonmagnetic portion. 87.85 0.07 3.2 /°.05 0.078 0.10 9-3 33-5

Calculated head , 1Th - l : ± 7 " 100.0 100.0 

1 L Less than.

2538 -13-
R. I. 4358

Flotation operating data

Pounds per ton of ore

Cleaner

Reagents Conditioner Rougher 1 2

Potassium smyl xanthate ....... 0.175

Methyl amyl alcohol .0.8

pH ........ ................. 7 ¢9

Time,, minutes .......... ... 3 4 3

The iron in the nonmagnetic portion was largely in the ferro-magnesian

minerals.

Spectrographic analyses of the copper concentrate and the magnetic and

the nonmagnetic portion of the tailing were made for silver, platinum, and

palladium. The results were as follows:

Product APt Pd

Copper concentrate ............. Low Negative Trace

Magnetic portion .Negative do. Negative

Nonmagnetic portion .. do. do. do.

This shows a silver and palladium concentration in the copper concentrate.

Using the same treatment procedure, but grinding to minus 65-mesh, recovered a copper concentrate containing 50.7 percent an iron concentrate

containing 62.7 percetit, and a reject containing 0.0k percent copper and

3.4 percent iron. Thus, the 65-mesh grind gave slightly lower recoveries of,

copper and iron but slightly higher-grade coppero and iron concentrates.'

A supplemental test was made to'study the possibility of preparing an

iron product suitable for the production of sponge iron by magnetic

concentration.

The sample was ground to minus 200-mesh, which is the size necessary for liberation of the iron.

The copper was floated from themisne -ore previous to'magnetic separation. The6results of the tests are as follows:

Magnetic concentratiolof mine. ore-(flotation tailing')

W Weight, Analysis, percent Percent ofXtotal - Product percent Fe Insol. SiO2 F Insol.

Magnetic ......... 7.32 68 11 60.1'''-' 04 ' Nonmagnetic ....... .. 92.68 -- 3.6 ' 7 - _ .39.9 99.6

Heads, calculated. IT 1O00QQ 6 o l0.0 1OQ.O 0 --Heads, analyed . . 8.6. -

The grade of the magnetic portions was improved by 200-mesh grinding, but open-hearth sponge-iron specifications as to insoluble were not met.

Iron recoveries also were lower.

2538 -14 -
R. I. 4358

Mill Tailing

Four mill-tailing samples were obtained fOr metallurgical testing. The

samples were analyzed separately and composited for metallurgical testing.

Analysis of each sample and the composite are-as followsAnalysis, percent.

Sample designation Cu Fe 5

Tailing 1 ............... 0.13 9.1 0.05

Tailing 2 ............... 0.20 8.3 0.05

Tailing 3 ............... 0.08 9.1 0.05

Tailing 4 ................ 0.10 9.0 0.05

Composite tailing .. a. 13 f...........0 ! - .05

The mill tailing had been treated by flotation for the recovery of

copper and was largely minus 35-mesh. Mineralogically, the composite tailing

and the mine ore were the same. Most of the bornite remaining in the tailing

was partly coated with malachite, and much of the residual chalcopyrite was

locked with gangue. Locking of the magnetite was noted in sizes as coarse

as 65-mesh.

Equal weights of the mill-tailing samples were composited for magnetic

separation tests. The material, as received, was treated in a Davis tube to

remove the magnetite. The product so separated contained only 56.8 percent

iron. A microscopic examination of the magnetic portion showed that much

gangue was locked with the magnetite at this size, approximately 35-mesh.

Another portion of the composite tailing was stage-ground wet in a

pebble mill to minus 65-mesh and separated in a Davis tube by 2 amperes of

current for 5 minutes, followed by 1 ampere for 10 minutes. The vanadium

concentrated in the magnetic portion. Most of the iron in the nonmagnetic

portion was in the form of ferro-magnesian minerals. A little recoverable

copper was released by the grinding. Results were as follows:

Magnetic-separations results

Weight, Ana lysis, percent [Percent of total

Product Dercent Fe jInsol. P iS Cu V2 5 Fe Insol. P

Magnetic portion.. 10.0 16.0 5.5 0.028 0.05 0.05 0.56 74.6 0.7 2.6

Nonmagnetic portion 90.0 2.5 82.1 0.115 o0.8 013 0.os25.4 99.3 97.4

Calculated feed 100.0 8 4 7 0.106- _ . 100.0 00.0

Supplemental tests to study the possibility of preparing a product

suitable for the production of sponge iron were undertaken on the mill tailing

as they were on the mine ore, previously described.

The sample was ground to minus 200-mesh, which was the size necessary

for liberation of the iron. The results of the magnetic concentration tests

are as follows:

2538 -15
R. I. 4358

Magnetic concentration of mill tailing

Weight, Analysis, percent Percent of total

Product percent Fe Insol. SiO2 Fe Insol.

Magnetic ............... 9, 18 67.3 4.3 1.60 ,69.4 0.5

Nonmagnetic .90.82 3.o 81.3 - 30.6 99.5

Heads, calculated . 100.00 -87,-9 7'4 _ - 100.0

Heads, analyzed ._..... . 89_

7

2538

2538~~~~ -16-