;ONCENTRATION OF KLUKWAN, ALASKA,

MAGNETITE ORE

Y R. R. WELLS AND R. L. THORNE

,* * * * * * * * Report of Investigations 4984

UNITED STATES DEPARTMENT OF THE INTERIO

Douglas McKay, Secretary

BUREAU OF MINES

J. J. Forbes, Director

Work on manuscript completed March 1953. The Bureau of Mines will welcome repri

of this paper, provided the following footnote acknowledgment is made: "Reprinted 

Bureau of Mines Report of Investigations 4984."

June 1
CONCENTRATION OF KLUKWAN, ALASKA, MAGNETITE ORE

by

R. R. Wells!/ and R. L. Thorne 2 /

CONTENTS

Pag

Introduction ................................................ 1

Acknowledgments..... ....................................... 1

Location and description......................................1

Exploration and mining ............ *.. ......... ........ 2

The ore ........................... ................. ..... 2

Samples................................... ................... 2

Physical character...................................... 3

Chemical character ......................................... 3

Methods of concentration....................................... 4

Sizing . . . . . .......... ............ 5 Sizing..k-floa.................................................... 5 Sink-float. . .......................... 6

Table concentration.................................... 6

Low-intensity wet magnetic separation ...................... 7

Coarse, dry magnetic separation .,............................. 12

Combined dry and wet magnetic separation ................... 1

Wet magnetic separation with re-treatment ............... ... 13

Proposed flowsheet ..................................... ...... . 15

Summary....................................... ...... .......

1

ILLUSTRATIONS

Follow

Fie. Tage -- a1. Map of Klukwan iron deposit .......... ................... 2

2. Iron grade vs. titania content ......................... 10

3. Proposed flowsheet, Klukwan ore ........ ........... 14

1/ Chief, Metallurgical Division, Region I, Bureau of Mines, Juneau

Alaska.

-- 2/ Mining engineer, Region I, Bureau of Mines, Juneau, Alaska

Report of Investigations 49841
- -7

INE RODUCTION

)r several years the Klukwan deposit near Haines, Alaska, has attrac

,t as "a potential source of iron. Limited field and laboratory inv

has indicated that the deposit contains a large amount of iron that 

7able as high-grade concentrate.

is report summarizes the results of laboratory beneficlation testin

Klukwan ore, as represented by six samples submitted to the Alaska

aent Station of the Bureau of Mines, Juneau, Alaska. Iron is presen

ore as a fine-grained magnetite associated with a pyroxenite-type

rock. Satisfactory magnetic-separation procedures were developed fo

)duction of concentrates assaying more than 60 percent Fe and 2 to 

TiO2 .

rring the investigation many data were obtained and compiled, but fo

Lence and clarity data of secondary importance have been omitted or

sed; only the more pertinent test results are discussed in detail.

ACNMOVTLE1GMENTS

ie authors of this report gratefully acknowledge the advice and ass

f S. H. Lorain, Regional Director, Region I, and J. A. Herdlick, ch

Division, Region I. Special acknowledgment is extended to H. J). H

M, Mortimore of the Region II staff for petrographic and spectrogra

;ions, Thanks also are given to H. E. Blake, Jr., and D. H. Bollman

;s, for the many analyses of ores and ore-dressing products, and to

loldsworth, commissioner, Territorial Department of Mines, A. Upton,

engineer, C.T Takahashi & Co., and C. L, Sainsbury, geologist-inJuneau field office, Geological Survey, for information and coope

I this project.

pecial acknowledgment is made to the Geological Survey for permissio

the topographic and geologic map data shown on figure 1.

LOCATION AND DESCRIFTION

ie Klukwan magnetic iron deposit is situated near the northern boun

;heastern Alaska at 59° 26' north latitude and 135° 53' west longitu

zwan, an Indian village, the paved Haines-Cutoff Highway passes over

'wash fan of the deposit approximately 1 mile from the lode, Klukw

miles by highway from Haines, a deep-water port on the shore of Lynn

T o . I a . . .I

The defosit i1 a verv Iar-ao masRsof basirpinP rc-k which confonns mnninp

FIcally to a magnetite-enriched pyroxenite. The maximum width of the de

L[i -1 -

LI
tIiI

i,i

; 

-
The deposit may well be a magmatic differentiation from the predominantl

dioritic magma that formed the backbone of the mountain chain. The magnetite

enriched pyroxenite is. enclosed within the diorite. Diorite crops out twithiln

the deposit in canyons 4, 5 and 6, as shown in figure 1.

EXPLORATION AND MINING

Some short-hole diamond-drill exploration has been done by a private

company. Conditions for long-hole diamond drilling are favorable; this

method of exploration could be utilized for a comprehensive evaluation of

the deposit at a very low cost per ton of iron-bearing rock.

Location and weather conditions present no serious problems for yearround mining and shipping. The character of the deposit is such that largescale, low-cost mining methods can be utilized.

THE ORE '

Samplesr * j 

Three of the samples submitted to the laboratory were chip or channel "

samples from the Klukwan lode; three others were obtained from the large

alluvial fan at the base of the mountain. I

5396 - 2 -

fig. 1) averaged approximately 20 percent magnetic iron and 5 percent iron '

contained in silicates. The sampled section appeared to be representative. 

It must be emphasized, however, that only small areas of the deposit have

been examined or sampled. Most of the outcrop is concealed by overburden or '

is inaccessible because of the precipitous topography; consequently, there is h

no assurance that all parts of the deposit, as mapped, are comparably ! ma4 no J-k& A.rA O 14 , e

above the lowest exposures.

Those parts of the deposit that have been examined at close range indicate that magnetite is disseminated uniformly throughout the pyroxenite,

except where magnetite or pyroxenite may be segregated into nearly pure

lenses. The average magnetic iron content of the magnetite lenses is Indi.

cated to be about 45 to 50 percent.

It appears probable that the average magnetic iron content of the deposit

will be governed largely by the relative number and size of the magnetite

lenses, but neither of those factors has been determined. One series of chip

samples taken by engineers of the Bureau of Mines across an 800-foot expanse

of uniformly crystallized pyroxenite near the lower end of Canyon 2 (see map,

as mapped, is approximately 1-1/4 miles; the length is approximately 3 miles

Erosion has exposed the deposit throughout a vertical range of about 3,000 -

feet, much of which is precipitous. A sketch of the deposit is shown in

figure 1. Information adequate for a dependable grade-tonnage estimate is

not available. The entire mass of magnetite-bearing rock, as mapped by the

Geological Survey, is estimated to contain at least 13 billion short tons
IiIII

ample 1 and 2 were 1-cubic -yard samples obtained by engineers of t

Division,.Bureau of Mines, from pits dug in the outwash (alluvial 

i of the deposit. Sample 1 was taken near the apex of the fan; sam

:en near one side of the fan about half wayr between the base and th

Sample 3 was a composite of three samples obtained by members of t

.cal-Survey staff from beds of fine-grained material near theouter 

alluvial fanl. Samples 4 and 5 were composites of chip samples tak

of Mines engineers from a section"'of the lode.deposit, known as Can

6 was a composite of channel samples cut in Canyon 5 and submitted 

)oratory by an engineer representing C. T. Takahashi & Co.

ie approximate locations from which the samples were taken are show

map of the Klukwan deposit (fig. 1).

Physical Characater

trographic examination of each of the samples submitted for testin

d that, in a broad sense, all are mineralogically similar. There 

, a variation in the relative amounts of the component minerals.

'o rock types were noted in the low-grade..ore (samples ( 2, 3, 4)

e was described as a gneissoid rock that contains hornblende, alter

feldspar (principally albite), some altered pyroxene, and small to mounts of biotite, epidote, zoislte, and apatite, The second type 

ally an altered pyroxenite that contains dominantly clinopyroxena and pigeonite) with associated magnetite and sphene and .varying of serpentine and chlorite. Minor amounts of calcite. ad limonit

entified.

e higher-grade ores (samples 5 and 6) essentially contain magnetit

ely small amounts of clinopyroxene (augite and pigeonite), and hor

with only very small amounts of sphene, epidote, clinozoisite, -calcic plagioclase, quartz, spinel, and apatite.

nute inclusions of magnetite in pyroxene were observed in all samp

rm known as a schiller structure, This extremely fine-grained mag

bably is not recoverable by ore dressing but represents only a sma

of the magnetite in the ore,

:roscopic and sizing studies revealed that maximum liberation of re

Le magnetite in the lower grade ore is achieved in the minus-150-p

i size range, The amount of locked magnetite in the. minus-100-plus

1 fraction is small but increases to considerable in sizes coarser )-mesh. In the higher grade ores, however, the recoverable magnet

Ally is liberated in the minus-48- plus-100-mesh size range.

Chemical Character

resentative head samples, carefully prepared from the samples subwere analyzed both chemically and spectrographically. Partial che

lyses of the samples are shown in table 1. Semiquantitative spect

analyses revealed the presence and approximate quantities of the. m

3 

-

i

II

I

-

Z
. .

I

Samble I Fe

.1 AssMa~, peElr~ent

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

2 ^ . . , a

3......

4......

6.. .

6 2 0 & 1-

: S L 9 - _ - ; A I . r t IA .- -

0,. ' 4 . ,

.9* ' ... *. *4, ..*'

5.* 90 *'. **.* ***o... ..... *. 90....0 **..... 6. .... .. . .. ...... *,

A

A

B

C

C

D

A iE

A E

A E

A F

B F

E IE

A

A

B

'C

QDr»

- -1-

listed in table 2. Any other elements, if present, aire in amounts lower tra lthe minimum detectable by the routine technique employed,

TABLE 1. - Chemical analyses

-re

17.4

15.6

13.2

16.8

54,0

51.9

rIo MSi & - c i

2.15

1.5

1.7

2.0

4.6

4 .-5

-- .

39.3

42.8

39.9

39.7

8.6

6,0

i P I S . ' Cu -- - r4- v * -=

o.o /o .02

.09: tL .02

.11 -.03

1/.02 .03

1/.02 .025

u.o .o2

0.051

:.02

- I

_J

NT L.O,.I.,

0,03 -

.- :I t r2. .5

- VV4--

0.05

.02

,01

.05

.29

.23M

LOunce Ver t 5

Au t

Trace Trace Trace T

T race Trace

Trace Trace

Trace Tra ce

. - $ .--- -- ,-- ---

--- Trace Trac p,

.l Less than.

2/ Mostly wood chips.

TABE 2, - Spectrograephic analyses I1

r.,~A.,

,. 1 --- . .. ........ - --- --- ·

J~4.0

E

F

E

E

E

A

A

A

A

A

A

Tel : l i iw

D

E

E

E

D

E

E

F

F

E

IE

siTTi

A

A

A

C

C

C

,

DD

D+

D+

v

D

E

E

D

E

Moi

-~

E.

F'

ai Z

i- ,

E ·i ;

. . - . . ~II - B: - 1 ;-1----- .I ----`- --

Legend:

A - over 10 percent.

B - 5 to 10 percent,

C - 1 to 5 percent.

i

E - 0.01 to 0.1 percent.* :t

F - 0.001 to 0.01 percent,

G - less than 0.001 percent.

D - 0.1 to 1 percent. ;

Magnetic iron, magnetite, or recoverable iron assays are empirical

analyses based on the percentage of total iron recovered in a concentrate by.

low-intensity wet magnetic separation at a selected grind. Thus, based on

treatment of minus-1CO-mesh ore, samples 1 and 2 contain approximately 11.8

and 9.4 percent magnetic iron, respectively.

"'

I?

Tests later described show that both the trade of concentrate and the

percentage of iron in the tailing depend, to a large extent, on the degree

of fineness of the feed, For this reason, all recoveries given in this

paper have been reported in terms of total iron rather than magnetic iron. '

M- EODS OF CONCMETRATIO

Iron ore is a low-priced commodity, This limits the amount of work the

can be expended on beheficiation and necessitates comparatively simple concentration methods.

Crushing and screening often arq employed on high-grade ores to prode

more satisfactory material for furnace .consumption. sWashing can be applied

to ores in which gangue is present: as fine material 'eadily separated TfrOAy

5396 4 - -

II

I

1.
I

I

h iron minerals, Jigging and, more recently, heavy-medium sink-float pro

*Bes have 'been used. successfully to concentrate ores in which gangue and i

erals are separated relatively coarse sizes, For ores finer than 3/16-i

ling and spiral concentration are considered to be the most applicable o

e various gravity treatments. 

Flotation methods are metallurgically feasible for the beneficiation o

ome hematite ores, but high reagent and grinding costs have made the proce

conomically unattractive.

Magnetic concentration methods are suitable for ores containing magne

r nrAina costs are usually high. but maanetic methods often have the advant

I i er flotation in that it is sometimes possible to concentrate in stages, e

ing waste in each stage, thus reducing the amount..of material to each

uceeding grinding circuit,'

The laboratory studies conducted on the Klukwan samples included prelim

y sizing and gravity-concentration tests. Because.the ore was fine gra

ver, the bulk of the test work was directed toward.development of a fea

tic treatment method, .... .. ,

Specifications for an iron concentrate vary widely,, depending on the p

for which it is to be used and the process employed to produce the fin

tal. For example, hematite ores containing less than 50 percent Fe are a

Epable for blast-furnace consumption, but specifications imposed upon mag

tite ores often require an iron content over 60 percent. The laboratory

tipg was directed, therefore, toward developing a treatment method to

duce a plus-60-percent Fe concentrate,

Although fine magnetite concentrates require sintering or nodulizing

fore use as blast-furnace feed, study of this phase of the problem was

Sidered to be beyond the scope of this paper.

Similarly the restrictions placed on titanium content of an iron ore v

th the smelting process to be employed, It is ,generally held that titani

rols iron ores are undesirable in blast furnaces if the titanium oxide co

t is above 2.5 to 3.0 percent. It is reported, however, that ores and

lters containing up to 10 percent TiO2 have'been treated successfully by

stt-"furnace smelting.2/ In addition, electric furnace methods have been

sloped to effect direct smelting of titaniferous ores. In this report,

elrefore, the titania content of the concentrate has been reported without

attempt to evaluate the product.

. sizn

Samples 1 and 2, as received, were screen sized dry, using foundry rid

d tandard Tyler sieves to produce a series of sized fractions from plus- 

eches to minus-20-mesh. Portions of each of the other samples were roll

Shed to minus -20-mesh and wet screened to yield sized products from plus

es~h to minus-200-mesh. None of the tests showed any marked concentrati

~s Jdale,elks, Titanium, Its Occurrence, Chemistry, and Technology:

Th e Aonald Press-Co., New York, 1949, pp. 409-412.

-5-.

L
1

r _ _ .: ~ : ~ - :__ z ~ .. . .

Product

Plus-4-inch ,.... o.. , ..... f 4.38 .. 11.6 3 9

'l.us-2-inch .,o.. .. .. ... *. .*. . 26 15,9 16.3

Plus-l-Inch .... ,.......... ... 14.81 13*5 12,6

2lus-l/2-inch .... ,..*,.,... 9.01 13.1 7,4 Plus-1/4-inch ................. 644 13.6 5.4

Plus-10-mesh ..*..,...e...,..,. 8.33 13.5 7.1

PlUB-20-mesh ............. . 8.05 8.0P l3u4 1 13.4 1 6.8

Mirnus-20-mesh ... ......... 32.72 i 197 I 40.

Calc. head .............. * 100.0 i .9 .- 10 .0.

Sink-Float

To.determine if either high-grade concentrate or low-grade reject co

be made at relatively coarse sizes, a series of heavy-liquid siikfloat t

was conducted on portions of sample 1 crushed to minus-3/8-inch, The med

used was tetrabromoethane, alone and in mixtures with carbon tetrachlorid

Several medium specific gravities were tried.

Results were poor. No reject was made that assayed less than 11,5 p

Fe, and no concentrate was made higher than 21.5 percent Fe.

*Table Concentration

Plus-4-inch ....... ..........

Plus-2-inch ..,oo* **.*e,*....

Plus-l-inch *..............

Plus -1/2-inch 1/4-Inch ............ **.............

T)D i i t- -It _in ," &k

concentration was noted below 48-mesh, These results corroborated the p

graphic reports, which indicated that only partial liberation was effect

coarser than 100-mesh for the low-grade ores and coarser than 48-mesh fo

the high-grade ssaples.

The results obtained from sizing samples 1 and 2 are

and 4 to emphasize the uniformity in grade of the various

shown in table

sized fraction

TABLE 3 - Screen analysis, sample 1

-t :. ct' *1'--, Weightpercent

'36.4

15.2

9.0

3.0

5.5

g 1

I A * sseay,

percent Fe

16.4

16.6

17.1

17.2

17.2

17.8

1945 ,

D'iercent u

pDercent 

* 35.6

14.3

8.5

2 ;9

5.5

5.3

5.5

! 22.4

P44lt-u-A a * O*eo J , 4a**lO9e r

Plus-20-mesh .......,** ... 5.4

Minus-20 -mesh .. ,.............. 20.1

Calc. head '.*.... 1 o-0..,.... .1000. 17.5 i l%.o ..5.. . 00.0 

TABLE 4, - Screen analysis sample 2

eigh- Assay, e Distriutio

_ __ Product_ _ Lre n --- pFe percentL pFe e percent prcn P

, , ,, , b -W ,,. -^ ^ , - ,. .

To determine the effectiveness of shaking-table concentration, portio

samples 1 and 2 were crushed to minus-20-meeh and treated, unaized, on a 

ratory shaking table. By this method 44 percent of the total iron in sam

- -
i

i

i

I

i

i

I

I

I

I

I

i

I

I

i,

~A recovered in a concentrate 

table middling 

that assayed 37.6 percent Fe. Inclusion 

sayed 28 7 percent 

increased 

Fe, 

the iron recovery to 70 percent; the resulting 

La: percent 

Treatment of sample 2 yielded a concentrate as

:tare and middling 

Fe and containing 35 percent of the' total iron. Combined c

percent Fe. In 

contained 76.5 percent of the total iron at a grade o

aterial treated 

each test, approximately 50 percent of the total weight o

was rejected as tailing that assayed about 9.0 percent F

The poor results obtained by table-concentration ted to locked particles treatment can be at

Ion bet1ween middling -and 

that 

tailing 

concentrated as a middling product. The gr

gs not 

was not sharp; hence, the reject produc

clean. One preliminary spiral-concentration 

;re virtially test gave results th

identical.

rrcial 

Table 

milling 

or' spiral concentration could not be considered for use in a c

plant except as a possible preliminary beneici.tion step 

Loy-Intensity Wet Magnetic Separation

Portions bOf each saniple-were ground to various sizes, as Indicated te jfollowfng tabulated in

Ltensity wet magnetic summary. ach ground portion was treated in a low

separator to yield mapgnettc 'and nonmagnetic fractio

oth 

,sulte 

the 

showing. 

recovery 

iron and titania content of the magnetic fractions, togeth

of total iron in these fractions, at summarzed ito.10., in tabl

inclusive.

. - L oTABwLE ntensity magnet earation s e

irind i .Weiht ssay,-Pere rcent Di; tribution erce

(Cmesh ' Product I .percernt Fe 1.TO: Fe TiO ...... Manetic --- j3.2. Nonmag. 6, .62 7.1 1.3 2i 3

Gale. head 100i00 17.01 2 1 g . - s .0 nus -3 ......... Magnetic . 24.9- 49.5 2.9 j 3 3. sNonmag .. 09 7 .1 1,9 20 66.5 *u4 '

a 

S *nutl head 0.oo 17.6 2.14 ~loo TO-- Magnetic 21 56.2 5w..... 2 .85 i =

.Nonmag. 7.2 1.9 32 3 1.3

r.°. 

ns5-n Magneti 1 606 2.4 8.0 .. .. Non"ag. 

Oal. 

803 70 2.1 32 .2 head 10,00 17.5 2.2 100.0 lus100,. MMaganetic i8o 64,3' 1.8 67.yil9 I Nonmag. 

Cale, 

81.20 7.1 2.2 32,3 84.1

uhead 100.00 17.8 2 1 1S0.0 100 0 .... . Magnetic 4.5 1.7 i

Nonmag. v 81,45 7 .3 225 -33 1

85 4

ooale. h^ead r; co 1 ,. :9 I I' 42o...... I17a 

--- I V __ ·-Y I -1. I I - I - I .- P 

Nonmag, a 8 .326 7.4 1 2.25 . 86.4 alc. -- heaad l :L c oO. 12.6 ! -, O.1 1^00

- 7 -
W w :

Grind

(mesh)

Minus -20, ......

Min3us-5 Minus -35. ,. ...... , ,

iinus . ,* * * *

Minus -65, .. .

Minus -100.......

Minus-150,.... .

Minus -200... ..

I WeightProduct i percent

Magnetic 23.91

Nonmag. I -76.0

Cale, head 100.00

Magnetic i 17.39

Nonmag, 826,

Clc, head ! 100IO0

Magnetic

Nonmag.

Cale, head

Magnetic

Nonmag.

Calc. head

Magnetic

Nonmag.

Calc. head

Magnetic

Nonmag .

Calc. head

Magnetic

Nonmag.

alc. head

* Results shown in table 5 indicate

quired to produce a plus- 6 0-percent Fe

contained 68 percent of the total iron

that grinding to mins -65 -mesh was re. --

concentrate from sample 1. This product

in the sample.

TABLE 6. - Low-intens.ity 'magnetic separation, sanple 2

!15.16

84 84

I CO .00

14.5o

1 85.50

14.o9

859

100.00

13.01

!00.00

12.75

1 87.2

I 100.00o

. - - - - -W-I -- , -" II

- , .

41.0 O

7.2

15.3

52.01

7.2

15.1

60.5

7.0

15.1

63.3

6.9

15.1

64.5

6.9

15.0

66.3

7.4

15.1

68.0

7.41

15.1 t -IJI

2.8

1.i

1.5

2.8

1.2

1.5

2.65

1.3

1.5

2.4

1.4

1.5

2.1

1.4

1.5

1 .8

1.5

1.55

1.4

1.6

1.55

f-: 

A .

t c r ,j *nir 

)C v 1. \r ""-'' SCty. amn-+ Distribution, percent

Fe T TiO2 Fe; Ti O3 ---- --- I · _c

6o.7

_ ' 39.3

100.0

60.9

39.1

inn n

i 64.2

I -. 8 i

mii 100.0

.j 6o.6

: '39.4-

YO0.= 100.0

suv.v

"f"*P'=l"

: 60.5

i .00,0- ---- . 0-t1 0 - -

57.3

42.7

44. --

55.6

100.0

32.9 67.1

26.7

-ni-I22.5

77.5

19.7

80.3

l1COO 2

15.2

fh f vArS -

_ 100.0 100 .0

57.3 ' 11.3

9I M, 42,7 88,.7

- . F-- -· ~Z ~:2 J t o 100.0 I °0.

The above results show that the iron content of the gangue remained

approximately the same as in sample 1. Hence; treatment of the lower grade

sample 2 resulted in lower percentage recoveries of the total iron. P'lus6 0-percent Fe concentrate was produced with a total iron recovery of 60.7

percent by treatment of ore ground to minus-48-mesh,

5396 - 8 -
Grind I j Weight -

(mesh) Product percent ,.,___ _L . . -. us -s0 ........ .I

Minus-35 ,..... I

I Minus -5.......

ius -100

| Minus -100 ...... ,

11

' , I Minus -150,... 0...*

Minus -200oo......

i MinUs 325$ 9 .. I

Magnetic

Nonmag,

Calc. head

Magnetic

Nonmag.

Calc, head

Magnetic

Nonmag.

Calc. head

Magnetic

Nonmag,

Calc. head

Magnetic

Nonmag.

Calc, head

Magnet ic

Nonmes,

Calc. head

Magnetic

Nonseg.

Calc. head

Magnetic

Nonmag.

Calc. head

13.49

86.51

100 ..00

10.34

12 .0

10.03

100,00

900.00

9.60

TABLE 7. - Low-intensity magnetic separation, sample 3

. .. ......-

Fe

Assay, -ercent Distribution. -erce

47.0

8,3

13.5

52.0

8.25

13.6

55.0

8,2

13.6

6o.o

8.2

13,6

62.3

8.o0

13.5

64,7

8*05

13.5

66,0

7.9

13.5

66.2

8.2

.' I

mi H, Ji~ ,;;,li*iiiii

Ti0C

2.5,

1.6

1.6

1.7

2.5

1.7

2.3

1.65

1.7

2.0

1.7

1.75

1.65

!.,65 1.65

1.65

1.65

i.65

I 1.2

1.7

Fe

46.9

51.1

1002.

46.6

53 .4

Intr n

, .- -T

19.3

80.7

.1QQ.0

17.8

82 2 _jJ L212*

- , J V S Id =dJ 

46,7 17.1

53.-- . .82.9

100,0 lOO0,

45.8 13.9

54,2 *36.__

100.0 i 100. 0

hr 11=-- 'I

I Ij

9,0.40

9,71

9.29

90.71

100.00

,, 53.7 i

100.0

46.o

_ .1000 _oo o 2

47.3

15-O.

45.3

, 54.7

88 4. -- 4--

100.0

9.6

90.4

100.0 

8.9

,91.1 

100.0

6.7

_:.21-3

I

-3.b . 1.7, 100.0 100.0 3h - - - | - - - - --- -- 1- ^I - -* eL h-ir II-- - ---- -- 

I,

H, I.- a Wet magnetic separation treatment of the low-grade sample 3 recover

4.6d percent

Percent Fe.

i concent rate

of the total iron in a magnetic concentrate that assayed 60

Minus-65-mesh grinding was required to prtoduce 60-percent F

- 9 -
1

, -- , -- ,- ,1_ -~__ , I R

Grind

(mesh) Product -. .. . ,, b .w, . -.- -, ,

mesn, approximately oj percenll or tne total iron was recovered in a conce

trate that assayed 63.6 percent Pe.

TABLE 9. - TLovy-intensity -magnetic separat ion sample 5 ,,~-- ~- .1-.,--- . .- ,,~~ ,, ,,-

"--- C - --- ------------r*---

Minus -20 *. ..

Minus -48. .....

Minus -65......

Minus -100..,.,.

Minus -200.,...

TABLE 8. - Low-intensity magnetic separation, sam1e 4

,' Magnetic

Nonmag.

Calc, head

,. Magnetic

I Nonmag.

, Calc. head

jMagnetic

I Nonmag.

j Calc. head

Magnetic

I Nonma.

! Cal . head

Magnetic

i Nonmag.

IS t A I e- lc. ha

weignt -

percent-

.73.42

, i Ii - . -4„ .1 ^ ^. .

AsSayj, pe rcent

1 8.69

.. '00'l1 100.00 I

16. 46

15 .721

84.28

10.co 1

1c~po

42,9

8.1

17.3

57.8

7.7

17.'1

17.0*

63.6

7.4

16,7

66.1

7.9

17.0

pi

.Fe [

.- .-- -- --- - .. -

2?,7

: 1.9

2.1

1.9

2.4 ,

2,1

.8

. 2.0

2.0

1.4

2,1

2.0

TIO 2

| - b~--ooI I'Ioo -/

1o-36.2 7o- - 100.0:

, 62.9 15.0

0 3.7.1 Q8.o0

1. 60.9 11.1

- 39.1 188.9 I 1oo.0 !I I 0. °

r- - -La- I

--- ,.--

i 65.7 1 67..2

-: 434 . .-,.32.8__

10Q0.0 100 lo0-. .5-.- --- , -E- -- 4;--a;; e

;63.3 23.9 I 36.7 7(.1

. Distribution, mP% .

Fe"' Tio0-

Wi"u, - O4IU ................. .. -- . -. . - -II----------·- --- -- ---

By wet magnetic separation treatment of sample 4 ground to minus-100- . . I - . I

Grind

(mesh)

, Weight - I

Product i percent r -. .. ..- - . .. .

Assar percent * Distribution, pert

i TiO i . Fe - - L i

- -- --

TiO2 ·_ _ II·__ _ __ __I __ __ II···_ I_ I___· _

Minus -20.. ......

Minus -........

Minus -65........

Minus-100,,..,.,

Minus -200.......

.- rC-rr l~-·rr*r

Magnetic 89.261

Nonmag. 10.74

Calc. head COo

Magnetic 85.06

I Nonmag. .14.94

Calc. head 100.O00

Magnetic. 83.51

Nonmag. 16.49

I C0l, head .100,00o

Magnetic 79 41

Nonmag, 202

Calc. head 100.00

Magnetic 81.68

Nonmag. .

.galo beaa h CoS.

60,8

9 ~5

55.2

63..6

10.0

55.6

64.0

10.9

55.2

65.6

10.9

53.9

65.8

11.0

96.3

-.

4.5

7.3

4.7

4.2

7.2

4.6

4.1

7.0

4.6

3.7

7.9

4.6

3.6

9.6

4.7

,

98.2

1.8 i1.83.6

*!QL

s - -

l_ __o.ot o -1 sj - - ;- r -1

96. 7 74.7

100.0 jl0

95.8 64.4

I 4.2 35.6 5- _oop0.o 'lo0o

96.4. r 62.5 .. 3.^6 37

? 100 °0 100.0

L__- · ·II --_-·_· ___.__·.._. ·· -- I-- _I __ ---

Plus-60 percent Fe concentrate was produced, with a total iron recol

of 98,2 percent, by magnetic separation treatment of sample 5 ground to i

20-mesh. Treatment at finer grinds increased the iron grade to as high s

percent Fe with only slight decrease in recovery. Titania content of al1

centrates was high, decreasing slightly with finer grinding,

5396 - 10 "

L

-,
L..

I.-

t-as=tz

ILl

Q.

PERCENT TiOt

Figure 2. - Iron grade vs. titania content.
I

r

I

I

I

il

i

I

I

1, I

" Grind

(mesh)

lin-us- 2 0 .,., . .

Minus -48. ......

Minus -65.... ...

Mlnus 100.......

i

iz

TABLE 10. - Low-intensity magnetig separation. sample 6

Product

Magnetic

Nonmag,

Calc, head

Magnetic

Nonmag.

Calc. head

Magnetic

Nonmag.

Calc. head

Magnetic

Nonmag

Calc. head

Magnetic

Nonmag.

Calc. head.

84.35 60.o0 4.3

1 x. 9.5 4.9

100 .00 52.1 4.4

80 25 62.6 4.0

19.75 . 10.3 6.0

100.00 52.3 4.4

78.03 64,0 3.7

21.97 10.7 6.2

100.00 52.3 4.3

77.22 64.7 3.6

22.78 10.9 7.0

100.00 52.4 4,4

76.59 65.7 3.5

i .41 1.1li 6.6 L 100,00! 52.9j 4.2

97.1

'-Q

wVJ ^wubV ! * 'j t A I xL u

100.0

96.1

3.9

95.5

100.0

95.3

4.7

100.0

95.1

4.9

100.0

Weight - itssay opercent i Distribution. per

rnro .In+ . i I Ta ta mr- n-4 .. .-L 

17.5

100.0

73.0

27.

100.0

67.9

32.1

100.0

63.

100.0

I 63.4

36.6

U

f

It

k

f

)0.......

mults obtained by wet magnetic separation of

btained by similar treatment of sample 5. T

)-mesh recovered 97 percent of the total iro:

60.0 percent Fe and 4.3 percent TiO2. Trea

1 yielded a product assaying 65.7 percent Fe

iron recovery of 95 percent.

general, it was determined that the iron co]

r in various parts of the deposit but appear

, Thus, the recovery obtainable by wet magni

.onal to the grade of the ore.

e degree of association of magnetite and ganj

ests indicated that minus-65-mesh' grinding ii

of concentrates assaying over 60 percent Fe

ir grade of concentrate can be obtained from

4inding to minus-20-mesh. The tests also shi

'r than 100-mesh resulted in an increase in 1

robably owing to sliming of a small amount o;

bulk of the titanium apparently is present

by magnetic separation treatment. A portioi

lherent part of the magnetite. An inverse rn

he grade of iron and the titania content in -

'ates. Although the same ratio does not exi.

curves show the same general trend. (See fd

Bureau of Mines Intermountain Experiment Si

d similar tests on a composite of the eight

- 11 -

sample 6 were simila

reatment of ore groun

n in a concentrate th

tment of minus- 2 00-m

and 3.5 percent TiO2

ntent of the gangue v

s to average 7 to 10 

etic separation is ro

gue also .varies. The 

s a requisite for the 

for low-grade ores b

high-grade ore by tr

owed that, in general

bhe iron content of t

f the magnetite.

as sphene and thus c

n of it, however, see

atio appears to exist 

;he cleaner higher-gr

st for all samples,

Lg. 2.)

;ation at Salt Ldke C

channel samples cut 

I 100.0
rortion was treated in a low-intensity magnetic separator to yield magneand non-magnetiC products. The results obtained from each sized fractlor

almost identiclal, allowig for limitation of accuracy in grinding, sample

prparation, analytical tecniques, and the slight difference in iron coni

of the various fractions. The results indicated that grinding to minus-E

mesh was required to produce iron concentrates assaying 60 percent Fe; al

67.5 percent of the total iron was recovered in a 60-percent Fe concentre

It will be noted that these average results are virtually identical to tt

shown in table 5.

Coarse. Dry Magnetic Separation

Visual examination of the ore showed certain particles of relativel1

coarse size that appeared to be composed almost entirely of magnetite grn

The minus-i-inch plus-1/2-inch and minus-1/2-inch plus-1/4-inch frae

of sample 2 ore were treated with a hand magnet to concentrate the most I

magnetic particles. The concentrates were sorted visually to select the

grade particles. Typical results are shownmin table 11.

TABLE 11. - Hnd magnet -soting treatment, sample 2. minus-1/2-inc h

{ eight- Assay, percent Distribut:

P roduct I rcent Fe ercent t

Sortel concentrate ............. 2.71 58.4 11.7

Midl ............. 42 20.6 50.7

ai.l n3...... ......... *.... 63.87 8.0 37.6

Calc. oo head....... ........... 10000 6 100.0

The hand magnet-visual sorting treatment showed that there is only

small portion of the iron present as large, relatively high-grade partic

The reject, however, assayed only 8.0 percent Fe and contained up to 65

of the total weight of the ore. These results indicated that magnetic s

tion at relatively coarse sizes could be used as a preliminary concentra

Combined Dry and Wet Magetic Separation

A series of tests were run in which screen-sized fractions of ores

2 were treated on a Wetherill-type dry magnetic separator to produce a 1

grade concentrate and a clean reject. Results of preliminary tests show

that consistently clean rejects could not be made at sizes above 20-mesb

Canyon 2 by engineers of the Bureau of Mines. The composite assayed 25.5 per

cent Fe. Wet magnetic separation of ore ground to minus-48-mesh recovered

81.6 percent of the total iron in a concentrate that assayed 61.3 percent pe - and 2.5 percent TiO2..

A study was made of sized fractions of sample 1 to further substantfate

the results obtained by wet magnetic separation treatment. Portions of each i

sized fraction, obtained from the previously mentioned sizing test were ground

to minus-20-, minus-35-, minus-48-, minus-65-, and, minus-1iC-mesh. Each groluna

5396 - 12 -
I

I

IIII

I

i

i

A, portion of ample 1 was crushed to a minus-20--mesh and screen sized,

ipg 35-, 65- and 150-mesh standard Tyler sieves. The two coarser fraction

ere treated separately on the Wetherill-type separator at the minimum mag

bjtnsity possible On the laboratory model. The products of each sized fra

ire combined. The combined magnetic product (28 percent of total weight) 

round to pass a 65-mesh screen and added to the original minus-150-mesh po

1,7 percent of total weight). The combined product was treated on a wet 

rtensity magnetic separator to produce a high-grade concentrate and a seco

qject.

Treatment of sample 2 was identical, except that the minus-150-mesh fr

rp was not removed, and the entire sample was treated by dry-magnetic sep

;lop. Bemoval of the fines is preferable, however, since they tend to clin

a. feed belt of the separator rather than be removed by the cross belts.

Results of these tests are summarized in tables 12 and 13.

TABLE 12. - Combined dr and wet magnetic separation, sample 1'-

.S t Weight- Assaypercent Distribution

Product o eercent e Ti0 2 pecent Fe

tpcentrate ...... ... . . .. .. 19.57 62.6 2.65 67.5

nonmawg. **,,...,*..* .,. 29.92 i 7.8 2.45 12.9

onmag ey * ....... *51 7.05 1.30 . 1.6

,0 . 00, i 1head8.........l.0. 81 1.9 1L0.0

TABLE 13. - Combined dry and wet magnetic snearation. sample 2

; Weight- j Assa P rcent Distribution

Product percent Fe TiO2 I percent Fe

ncentrate ....... a. t .21 . 0* 2 *. .^ o

nonmag, 4 ........ ' .. ,,' 16.55 7.8 2.2 8,7

nonmag, ...... . .69.2 ... 4 7.1 ' .1 1.0 i 33.3 beal......o. 1.4.8 1..4 1 lOQ.'O

Dry magnetic separation of minus-20-mesh ore followed by grinding and 

eatment of the magnetic portion in a wet low-intensity magnetic separator |Covered 67.5 percent of the total iron of sample 1 and 58.0 percent bf th

O of sample 2 in concentrates assaying plus- 6 0-percent Fe. The recoverie

MtSely approach those made by fine grinding and magnetic separation. (See

'tles 3 and 4.) The combination treatment has the added advantage of reje

g a large portion of the ore after only a minus-20-mesh grind.

Wet MgGetic Searatiop With ratment

The ore, as mined, would contain some. moisture and would require. dryin

'dry magnetic separation treatment were to be used. Therefore, investigati

? made of wet magnetic separation at relatively coarse sizes, followed by

'erinding and re-treatment. The results shown in tables 14 to 19, inclusive

te obtained by treatment of ore ground to minus-20-mesh in a wet low-inte

rsator, regrinding the magnetic portion to minus-65-mesh, and re-treatmen

Itbe same machine.'

- 13 -
Product !percent Fe

Concent rate... . 13.96 2.

rrr4tnA + o41 1 77 !C A M , 2,2 ct 2r2

S e-

. -ii 

TAHLE 1.4. - Wet magnetic separation with re treatment, sample 1

lWe-ight.-. As'a-., percent- Distribt

Less than.

TABLE 15. - Wet manetic separatioonwith re-treatment, sample 2

aeiPro- ~T gt- du' e percent T- Asct say..-perceent iP i Distst rinb ribZ;__

ktoJLun *v 3^ 1

*7

.6

0-,

-B I 0 ?nI . Ir -f - x II ., .

Ya .02 0, 4.4 - , - -

tino

Fe

Tail.. ... * . 78.25 .

Calc. head..... 100.00

1/ Less than.

TABLE 16. - Wet

Product

Concentrate....

Regrind tail.,,.

Tail...........

Calc. head.....

Weight -

percent

9.67

3.82

-86.51

100.00

ITi02 i P S ito02 i

1.1 _ - :y-JI.· I)-·IY·e-Y-

I/ Less than.

TABLE 17. ,- Wet

!Weight -

Product Ipercent

Concentrate .. 16.96

Regrind tail... 9.62

Tailc head..... 0.042

Calc. head... 1,. 0.00

' _ r ',- - „-- -i-' - „, * ,, „-.,„ 

y .

0.40 584O -

V .evrce__n

At

perc - nt ,iFe percent Fef;i

--- *!

-l.

l/ Less than.

TABE 18. - Wet

Product

Concent rate....

Regrind tail...

Tail.. -'.'.......

Calc. head.....

Cemb . roughe'r

concentrate..

I/ Less than.

Weight -

percent

83.89

5.37

10.74

100.00

89.,26

m - --

Fe ITi

Di stributi

percedit F

64,0

10.0

9.5

55.2

4.2

8.8

7.3

60.8 ! 4.5

5396 - 14 -
I V 4- OVERSIZE ---

TO

WASTE

CRI

-

JSHED ORI

00

E

ROLL CRUSHER

20-MESH SHAKING SCRE

UNDERSIZE

.O D E R i Z4E

TO .- CROCKETT TYPE WET

WASTE - R EJECCT-- E MAGNETIC SEPARATOR

ROUGHER

CONCENTRATE

RALL

| MILL rJ

I PLUS-65-MESH

MINUS-65- MESH

'

4-REJECT - CROCKETT TYPE SEPARATOR

CONCENTRATE

Figure 3. - Proposed flowsheet, Klukwan ore.

- -
i I

Product

ocent rate....

egrind tail...

I fal ea.....

Calc. head....*

Ileight -

percent

77.53

6.82

15.65

100.00

- 84*35

Fe

i4.o 14.0

9.5

52.1

6o.o

I

Ti02

3.7

11.1

4.9

4,4

4.3

TABLE 19. - Wet magnetic separation with re-treatment. sample 6

I Assa'V Tri rrc'nt.

. ~i..- -

.. P-- P

0.02

-

S

0.03

I.

r-. -- --

0.45

Si0p i V

0.32

-

-J

-m

Dist ribution

percent Fe

95.3

1.8

100.0

97.1

Comb, rougher . concentrate .

Less than. - .-

Wet magnetic separation of ore crushed to minus-20-mesh rejected a gre

ulk of ore as tailing than comparable dry magnetic treatment, thus further

educing the amount of rougher concentrate for regrinding. Overall recover

(nd grades of final concentrates were as good as, and sometimes better than

those obtained by combined dry-wet magnetic treatment or by wet magnetic

Ieparation of the entire sample ground to minus-65-mesh.

Since the high-grade ores (samples 5 and 6) yielded 60 percent Fe conentrates by treatment at minus-20-mesh, the re-treatment stage possibly co

eeliminated if similar high-grade ores were being treated separately.

The concentrates made from Klukwan ores are similar to Swedish ores in

hathe sulfur and phosphorus content is low. They should, therefore, be

litable to electric furnace smelting for the production of low phosphorous

id eel,

P roposed Flowsheet

Treatment by wet magnetic separation followed by grinding and re-treatm

t *the rougher concentrate could be accomplished by a simple flowsheet such 

at shown in figure 3.

SUMMARY

Six samples of ore from the lode and alluvial fan of the Klukwan iron

ePOlt proved to be amenable to beneficiation treatment for the production 

tl'Ontrates assaying more than 60 percent Fe.

l y Most satisfactory treatment method appears to be wet magnetic separatio

j tre ground to minus 20-mesh, followed by grinding and re-treatment of th

P gher concentrate. By this method, concentrates assaying 62 to 64 percen

fere made with total iron recoveries ranging from 45 to 97 percent depen

n the grade of the sample treated. These recoveries correspond to

Ceoveries of about 98 percent of the magnetic iron in all tests.

It Titanium oxide content of the concentrates made from low-grade ores

raged about 2.2 percent. Concentrates from highergrade samples, howeve

-- f^ : ined up to 4.2 percent TiO2.

u. of Mines, Pgh, Pa15

-Bu. of Mines, Pgh., Pa.