DEPARTMENT OF THE INTERIOR ^ 

HUBERT WORK, Secretary *^

UNITED STATES GEOLOGICAL SURVEY

GEORGE OTIS SMITH, Director 

Bulletin 761

MOLYBDENUM DEPOSITS

A SHORT REVIEW

BY a 

FRANK L. HESS

WASHINGTON

GOVERNMENT FEINTING OFFICE 

1924
7/3

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CONTENTS

Page

Foreword________________________________ __ 1

Characteristics of molybdenum minerals and deposits________ 1

Production of molybdenum ores ____________________ 8

Molybdenum deposits___________ _ ______________ 9

United States_______________________________ 9

Molybdenite_____________________________ 9

Colorado ____________________________ 9

New Mexico __________________________ 13

Arizona _ __________________________ 13

Other localities _____ ___ ____________ 14

Wulfenite_________________________________ 15

Canada ______ _ __ __ ______ 16

Mexico _____________ _ _ _______ 18

Virgin Gorda _________________________________ 18

Peru_____________________________________ 19

Bolivia _________________________________ 20

Chile______________________________________ 20

Australia___________________________________ 20

Queensland___________ __________________ 20»

New South Wales___________________________ 23"-

Victoria_________________________________ 25-

South Australia_____________________________ 26

Western Australia _______-____-_____________ 26

Tasmania____________..____________________ 27

Northern Territory______ __ _____________ 27

Norway __ _______:_______________________ 27

Sweden _________________________________ 30''

Germany ______________ ___________________ 30'

Austria_____________________________________ 30'

Yugoslavia __ _________ __________________ 30'

Spain_____________________________________ 31.

Japan ______________________________________ 31

Chosen____________________________________ 32'

China __ ____________ __________________ 32:

Transvaal __________________________________ 33

Other countries ________________ ______________ 33

Summary__________________ __________________ 33-

Index__ _____________________________________ 35'

ni

278095
ILLUSTKATIONS

>Fage

PLATE I. Molybdenite from quartz veins: A, From Railroad Creek near 

Lake Chelan, Okanogan County, Wash.; B, From a prospect 

near Lake Tahoe, Calif______________________ 4

II. Silicified and sericitized quartz porphyry (?) carrying molybdenite along veinlets, Climax, Colo______ _________ 4

III. A, Radial spherule of powellite, altered from molybdenite, 

from a pipe in quartz monzonite in the Deep Creek Mountains, 4 miles south of Gold Hill, Tooele County, Utah; 

B, Sericitized quartz porphyry breccia with a cement of 

quartz, sericite, and molybdenite_________________ 4

IV. Replacement of granite by molybdenum-bearing solutions: A, 

Radial mass of molybdenite brought in by solutions along 

crack, now healed and almost invisible, in fine-grained 

granite, Tunk Pond, Maine; B, " Miarole " where granite was 

removed and only partly replaced by molybdenum-bearing 

solutions traveling along minute cracks, now healed and invisible, Cooper, Maine________________________ 4

V. A, Molybdenite flakes scattered through contact-metamorphosed 

gneissoid limy sediment, Johnson, Ariz.; B, Molybdenite from 

a pipe near Gold Hill, TJtah__ _ 4

VI. Radial molybdenite from pipe (?) in granite, George Fast's

mine, near La Trinidad, Sahuaripa district, Sonora, Mexico- 4

VII. Ends of radial plates of molybdenite shown in Plate VI___ 4

VIII. A, Crystal of molybdenite from contact-metamorphosed limestone, Quebec; B, Part of a crystal of molybdenite from a replacement deposit in gneiss, Ogden mine, Edison, N. J____ 4

I.. A, Tabular yellow crystals of wulfenite, varying considerably 

in thickness, Organ Mountains, N. Mex.; B, Yellow crystals 

of wulfenite approaching cubical dimensions, Organ Mountains, N. Mex__ 4 

X. Workings of the Climax Molybdenum Co., Climax, Colo____ 5 

FIGURE 1. Principal molybdenum deposits in Canada, the United States,

and Mexico __ ' 9

2. Principal known molybdenum deposits of South America and " 

the West Indies_____-______ 19

3. Principal known molybdenum deposits of Australia and Asia_ 21

4. Principal molybdenum deposits of Europe 28

IV
MOLYBDENUM DEPOSITS A SHORT REVIEW 

\ BY FEANK L. HESS

FOREWORD

The arms of commerce now reach so far, railroad and steamship 

lines that give rapid and easy transportation are spread so broadly, 

and diffusion of knowledge takes place so quickly that trade can not 

be local except in those articles which supply only local needs, which 

occur or are produced only in small quantities, or which are of 

small value compared to their bulk. A corollary of this statement 

is that one who wishes to enter any business not restricted to small 

or local needs should know the general conditions of the business.

These remarks apply to molybdenum mining. The mining of 

molybdenum, in common with nearly all mining except perhaps that 

of gold and the other precious metals, should be undertaken only 

after consideration of the demand and the available resources, and 

these are synonymous with the world's demand and resources.

The United. States Geological Survey's annual publication " Mineral Resources of the United States" reviews uses, demand, and 

prices. An attempt is made in this paper to give an epitome of the 

world's larger molybdenum resources so far as they are known, in 

order that those who are interested in mining molybdenum may 

better appraise the competition that they must meet and that those 

who are interested in the use of molybdenum may estimate the probable supply. No effort has been made to refer to the smaller deposits 

unless for some special reason, and therefore the paper makes no 

pretense of cataloging all occurrences of molybdenum. The references given will help interested readers who are near libraries to 

pursue the subject much further if they wish.

CHARACTERISTICS OF MOLYBDENUM MINERALS AND

DEPOSITS

The occurrences of molybdenum minerals in the United States 

are legion, and those in the world are countless, but the deposits that 

can be profitably worked are comparatively few. Molybdenum min-
'2 MOLYBDENUM DEPOSITS

erals are found in greater or less quantity almost everywhere that 

the nonferrous metals are mined and also in many magnetite-bearing 

areas, but they do not necessarily occur in the same deposits as the 

other metals nor even close to them. Molybdenite is also found at 

many places in igneous rocks and highly altered sediments where 

other metallic deposits are unknown or unimportant. Molybdenum 

is commonly associated with tin, tungsten, bismuth, and copper 

deposits, and wulfenite is in certain regions an oxidation product of 

lead veins.

The minerals of molybdenum are few. Only seven are surely 

known, and only three or possibly four are found in sufficient quantity to form ores. The known minerals are as follows:

Molybdenite, molybdenum sulphide, MoS^; contains 60 per cent of molybdenum.

Wulfenite, lead molybdate, PbMoOi; contains 26.16 per cent of molybdenum.

Chillagite, lead tungsto-molybdate, Pb(W,Mo)O4; contains 11.68 per cent 

 of molybdenum.

Molybdite, hydrous iron-molybdenum oxide, 2(FeO2 ).6Mo03.15H20; contains 

'66.7 per cent of molybdenum.

Ilsemannite, possibly a molybdyl molybdate, MoO2 .4MoO:).

Powellite, calcium molybdate, CaMoC^; contains 39.05 per cent of molybdenum. Some specimens contain tungsten.

Koechlinite, bismuth molybdate, (BiOaMoO*; contains 15 per cent of 

molybdenum.

Achrematite, a lead arseno-chlor-molybdate; belonesite, a magnesium molybdate; erosite, a vanado-molybdate of lead; jordisite, an 

.amorphous sulphide of molybdenum: and pateraite, a cobalt molybdate, are all more or less questionable minerals that have been named 

from impure or insufficient materials. Halotrichite (hydrous ironaluminum sulphate), aluminite (hydrous aluminum sulphate, containing more or less iron), and melanterite (hydrous iron sulphate) 

colored blue by molybdenum have been reported. The determination 

of the aluminite is possibly questionable. Some scheelite carries 

molybdenum, but I have found no record of such scheelite in North 

America. Only molybdenite, wulfenite, molybdite, and possibly ilsemannite have been found in commercially valuable quantities.

As is apparent from their chemical composition the molybdenum 

minerals are found under a variety of conditions.

Molybdenite is by far the most widely distributed molybdenum 

mineral, occurs in the greatest quantity in individual deposits, and 

is the molybdenum mineral in most of the ore produced. It is 

found in quartz veins, either as an original constituent or as a 

later filling of cracks; in pegmatite, though probably always 

deposited in the dikes after their solidification; in those deposits 

formed by the replacement of granitoid rocks that resemble pegma-
CHABACTERISTICS 3

tite and take the form of pipes or more tabular masses; in greisen, 

a silicified granitic rock containing more or less muscovite (white 

mica); in granite, but probably not as an original constituent though 

often so described; in regionally metamorphosed rocks; and in contact-metamorphic deposits. Molybdenite has a bright metallic luster, 

like new sheet lead, and in many places occurs in thin flakes, like 

mica. Where the flakes are spread through white quartz or some 

other light-colored rock they give the impression of a quantity much 

greater than really exists. Owing to its attractive showiness and 

its evident metallic properties, it gains attention wherever found.

In general, though not exclusively, molybdenum is found in association with the siliceous igneous rocks. Analysis of a trachytic 

obsidian collected by Cross 1 in Hawaii showed a trace of molybdenum, but the quantity present, if any, as an original constituent of 

igneous rocks is so small that it is barely detectable by chemical 

means,2 and all assured traces that Hillebrand found were in rocks 

that were at least as siliceous as monzonites. When the rocks cool 

the molybdenite seems to be almost totally pressed out with the 

watery fluids and is deposited in the zone that is cool enough for 

the deposition of quartz, mica, chalcopyrite, bismuth, and tungsten 

minerals. It is found in a few places with cassiterite and was probably either deposited there before the rocks were hot enough for 

tin in the ore-bearing solutions to reach these particular places or 

after they had cooled subsequent to the deposition of the cassiterite.

Quartz veins carrying molybdenite that has been deposited with 

the quartz are likely to have a border on each side of muscovite or 

biotite flakes standing normal to the vein, and the quartz is usually 

of the glassy, splintery varieties that seem to be commonly formed 

close to a magma from which the solution carrying the quartz has 

been squeezed out. I examined a clearly exposed vein of this sort on 

the Marta property, about 15 miles northeast of Quimsa Cruz (Tres 

Cruces) Pass, Bolivia. Here the veins run from the contact of 

quartz monzonite with quartzite into the quartzite. There is no 

trace of the veins in the monzonite, but they start abruptly from 

the contact. The veins are not long possibly 150 feet and the 

solutions probably cooled rather quickly.

In other quartz veins the molybdenite may be partly deposited 

with the quartz and partly in cracks in it. A. few of the veins, like 

that above Hortense, Colo., carry beryl and feldspars and are apparently closely related to pegmatite.

1 Cross, Whitman, Lavas of Hawaii and their relations: U. S. Geol. Survey Prof. 

Paper 88, p. 51, 1915. Analysis by ,T. B. Ferguson.

2 See analyses by Hillebrand, W. F., Distribution and quantitative occurrences of vanadium and molybdenum in rocks of the United States: U. S. Geol. Survey Bull. 167, pp. 

50-51. 1900.
4 MOLYBDENUM DEPOSITS

The molybdenite in quartz veins may be either in fine disseminated flakes or in excellently formed large crystals. (See PI. I, 

A and B.) The largest crystals known to have been found in the 

United States are some about 3 inches across and an inch thick occurring in a quartz vein at the head of Kailroad Creek, west of 

Lake Chelan, Wash., but plates 12 inches across by a quarter of an 

inch thick were found in quartz veins on .Quetachu-Manikuagan 

Bay, on the north shore of the Gulf of St. Lawrence, Quebec.8 In 

many veins molybdenite has been deposited in cracks after the 

formation of the veins, and a little movement has ground it to 

" paint" which smears the surfaces of the quartz. The siliceous 

solutions that in some places form simple quartz veins may in others 

replace the country rock, and the molybdenite they carried also replaces it.

The deposits in pegmatite are probably to be classed here, for the 

molybdenite in these deposits has, so far as I have seen it, been 

brought in after the solidification of the pegmatite. Commonly, as 

in some granitic rocks, the cracks along which the ore-bearing solutions have moved are small and so well healed as to be almost or 

quite invisible to the unaided eye. The molybdenite is deposited 

molecule by molecule as the minerals of the pegmatite are removed, 

and from its appearance it might be supposed to be original in the 

rock. Such replacement occurs in granite, and a tiny, almost or 

quite invisible crack may lead to comparatively large masses of 

molybdenite in apparently solid granite. This is the origin of all 

the supposed original molybdenite in granite that has come under 

my observation. (See PL IV.)

In places, probably owing to the heat of the solutions, the pressure, and the compounds carried, the silica instead of merely filling 

openings replaces the country rock on each side, and if the process 

occurs in a greatly brecciated zone, the formation of a highly silicified deposit, with accompanying sericitization (see PL II), such as 

that at Climax, Colo., may result, or the country rock may be attacked and part of its substance exchanged without a total replacement, leaving it a comparatively soft mass of sericite or kaolin, like 

rock along the veins of Questa, N". Mex.,4 or hard and vuggy the 

"miarolitic" granite of petrographers like the deposits at Tunk 

Pond and Cooper, Maine. 5 (See PL IV.) Flakes of molybdenite in

8 Geology of Canada: Canada Geol. Survey, Report of progress from its commencement 

to 1863, p. 755, 1863.

4 Larsen, E. S., and Ross, C. S., The R> & S molybdenum mine, Taos County,. N. Mex.: 

Econ. Geology, vol. 15, pp. 567-573, 1920. Although these authors say that there is 

almost no replacement of the " alaskilo " (the country rock), on the same page they say 

that " sericitlzed alaskite lies between the small branching veins," and they also state 

(p. 570) that close at hand " The rapid erosion in these sericitized areas has exposed 

large patches of white iron-stained rock that can be seen on the mountain sides for 

many miles."

B Hess, F. L., Some molybdenum deposits of Maine, Utah, and California: U. S. Geol. 

Survey Bull. 340, pp. 231-236, 1908.
U. S. GEOLOGICAL SURVEY BULLETIN 761 PLATE I

A.

B. 

MOLYBDENITE FROM QUARTZ VEINS.

A. From Railroad Crock near Lake Chelan, Okanogan County, Wash.; B, from a prospect 

near Lake Tahoe, Calif.
U. S. GEOLOGICAL SURVEY BULLETIN 761 PLATE II

S

V *

. ^J ,.^Af

SILICIFIED AND SKIUCITIZED QUARTZ PORPHYRY (?) CARRYING MOLYBDENITE ALONG VEINLETS, CLIMAX, COLO.
U. S. GEOLOGICAL SURVEY BULLETIN "61 PLATE IV

 r <r. *

fl^

B.

REPLACEMENT OF GRANITE BY MOLYBDENUM-BEARING 

SOLUTIONS.

A, Radial mass of molybdenite brought in by solutions along crack, now healed and 

almost invisible, in fine-grained granite, Tunk Pond, Maine; B, "Miarole" 

where granite was removed and only partly replaced by molybdenum-bearing 

solutions traveling along minute cracks, now healed and invisible, Cooper, Maine.
U. S. GEOLOGICAL SURVEY BULLETIN 7fil PLATE III

A. RADIAL SPHERULE OF POWELLITE, ALTERED FROM MOLYBDENITE. 

From a pipe in quart/ nioiizoniU: monzonite in the Deep Creek Mountains, Mountaj 1 miles south of Gold Hill,

Tooele County, Utah.

:*ry "v -^a?: ^f 

 p\ i ' m

"!ff . '

./ - ' fe

\

I 

> -

JJ. SERICIT1ZED QUARTZ I'OHPHYRY BRECCIA WITH A CEMENT OF QUARTZ, 

SERICITE, AND MOLYBDENITE.

From Emigrant Creek, near Chico, Mont.
U. S. GEOEOGICAL SURVEY BULLETIN 761 PLATE V

A. MOLYBDENITE FLAKES SCATTERED THROUGH CONTACT-METAMOR- 

,..,. PHOSED LIMY SEDIMENT, JOHNSON, ARIZ.

B. MOLYBDENITE FROM A PIPE NEAR GOLD HILL, UTAH.

Accompanying minerals are scheelite (sh), apatite (a), and sphene (sp) in a groundmass of partly

altered hornblende.
U. S. GEOLOGICAL SURVEY BULLETIN 761 PLATE VI

iRADIAL MOLYBDENITE FROM PIPE (]', IN i,I! \NITE, GEORGE FAST'S MINE, NEAR LA 

TRINIDAD, SAHUARIPA DISTRICT, SONORA, MEXICO.
U. S. GEOLOGICAL SURVEY BULLETIN 761 PLATE VII

ENDS OF RADIAL PLATES OF MOLYBDENITE SHOWN IN PLATE VI. 

The white mineral is quartz.
U. S. GEOLOGICAL SURVEY BULLETIN 761 PLATE VIII

A. CRYSTAL OK MOLYBDENITE FROM CONTACT-METAMORPHOSED 

LIMESTONE, QUEBEC.

II. PART OF A CRYSTAL OF MOLYBDENITE FROM A REPLACEMENT 

DEPOSIT IN GNEISS, OGDEN MINE, EDISON, N. J.
U. S. GEOLOGICAL SURVEY BULLETIN 761 PLATE IX

A. TABULAR YELLOW CRYSTALS OF WULFENITE, VARYING CONSIDERABLY 

IN THICKNESS, ORGAN MOUNTAINS, N. MEX.

B. YELLOW CRYSTALS OF WULFENITE APPROACHING CUBICAL DIMENSIONS, ORGAN MOUNTAINS, N. MEX.
U. S. GEOLOGICAL SURVEY BULLETIN 761 PLATE X

WORKINGS OF THE CLIMAX MOLYBDENUM CO., CLIMAX, COLO.
CHAEACTEKISTICS 5

such granite have been referred to by many writers as original in the 

granite, but I believe that they are invariably introduced after the 

cooling of the granite and are replacement deposits, like the other 

minerals that usually surround or occupy the miarolitic cavities.

If sericitization is the more active process and the deposition of 

quartz comparatively much less, such deposits as that near Chico, 

Mont., result. (See PI. Ill, B.) If the solutions are more complex 

the wall rock may be replaced by a surprising list of minerals forming pipes that are frequently called pegmatites, like those of the 

Deep Creek Mountains, Tooele County, Utah, and the Transvaal,6 

or some of those in Queensland 7 and New South Wales.8 In the 

Deep Creek Mountains, 4 miles south of Goldhill, the molybdenite 

is radial and some masses form complete spheroids. (See Pis. Ill, 

A; V, B.) A specimen showing similar radial structure (see Pis. 

VI and VII) but with a radius of more than 5 inches, from what 

seems to be a deposit formed in the same way, was sent to the 

United States Geological Survey by George Fast from his mine near 

La Trinidad, in the Sahuaripa district of Sonora, 225 miles by trail 

south of Nacozari, Mexico (U. S. National Museum specimen No. 

90438).

Molybdenite is found in many contact-metamorphic deposits, and 

although no large deposits of this kind are known in this country, 

some work has been done on deposits north of Golconda, Nev., near 

Baker City, Oreg., and on Pine Creek, near Bishop, Calif. A large 

contact-metamorphic deposit in limestone exists at Yetholme, New 

South Wales.9

The minerals accompanying the molybdenite are those usually 

found in tactites (the rocks formed by contact metamorphism) 

namely, garnet, epidote, hornblende, pyroxenes, scheelite, sulphides 

of iron, copper, and zinc, zeolites, and others. The molybdenite may 

occur as mere flakes, but some deposits show more or less crystal 

form. Plate VIII, A, shows part of a crystal in the United States 

National Museum (No. 83985) from a deposit in Quebec, the exact 

locality of which is unknown. Plate V, A, shows flakes of molybdenite in a contact-metamorphosed gneissoid limy sediment from a 

prospect near Johnson, Ariz.

Molybdenite is sometimes found in gneiss and has apparently been 

introduced in solutions while the gneiss was under great heat and 

pressure at a considerable depth. In the occurrences I have seen the 

molybdenite was associated with glassy quartz and followed the glid6 Wagner, P. A., The Mutue Fides-Stavoren tin deposits: Union South Africa Geol. 

Survey Mem. 16, pp. 127-128, 1920.

7 Ball, L. C., The geology of Wolfram, N. Q.: Queensland Qovt. Min. Jour., vol. 20, pp. 

509-511, 1919; vol. 20, pp. 6-11, 50-56, 1921.

8 Andrews, D. C., The molybdenum industry of New South Wales: New South Wales 

Geol. Survey Mineral Resources, No. 24, pp. 92-117, 1916.

8 Idem, pp. 170-189.

94093 24 2
6 MOLYBDENUM DEPOSITS

ing planes. Cracks in quartz are so easily healed, however, that too 

much weight must not be given to such evidence of depth and high 

temperature. Molybdenite is found in gneiss accompanying sheets 

or broad lenses of magnetite in the Franklin Furnace area, N. J.,10 

and in limestone not far away, and the two occurrences seem very 

closely related. The crystal shown in Plate VII, #, came from the 

Ogden mine, at Edison, in this area. The original is in the museum 

of the University of Manitoba at Winnipeg.

Wulfenite occurs only in the oxidized parts of lead veins, and the 

veins that carry it are found in rather small areas, of which that 

embracing the southwestern United States and northern Mexico is 

the largest and most productive, but Spain, Austria, Yugoslavia 

(Slovenia), and Germany are also producers. Although wulfenite 

has been found as specimens in many other places, it is a remarkable 

fact that most of the large lead deposits in numerous mining centers 

carry none or almost none of this mineral in their oxidized zones.

Wulfenite is usually yellow, rare specimens are colorless, and some 

are brownish or reddish and many of the tints are very pleasing. 

The wulfenite crystals are ordinarily clean and splendent, and in 

those mines in which it has formed freely, such as some parts of the 

City Rocks mine, at Alta, Utah, and the mines at Shultz, Ariz., the 

effect given by the reflection of mine lights from the myriad of scintillating facets is marvelously beautiful. A red color in wulfenite 

seems to be due to vanadium, and apparently the depth of the red 

color is proportional to the quantity of vanadium present. Wulfenite usually forms in flat plates ranging in size from those that are 

microscopic to those that are more than an inch along the edge. The 

thickness of the plates varies in the same degree. Some are paper 

thin, though half an inch broad. Others thicken until they approach 

cubical form, or if the edges were truncated (beveled) when the 

crystal began growing they may make bipyramidal forms. Plates 

of moderate thickness are shown in Plate IX, A, and nearly cubical 

crystals in Plate IX, B. Wulfenite is undoubtedly formed from 

molybdenum original in the vein, though the original mineral has 

never been identified. It is possible that molybdenum may take the 

place of a small part of the lead in galena, and so wulfenite is formed 

through the oxidation of the galena. Numerous writers have believed that it is collected from the country rocks cut by lead veins, 

but, as in the Sierra de los Caballos, near Engle, N. Mex., veins cutting the same rocks may vary widely in their wulfenite content, 

though they may be equally rich in galena.

Some wulfenite carries a little tungsten, and concentrates of wulfenite and vanadinite from Shultz, Ariz., contain as much as 2 per

10 Spencer, A. C., U. S. G-eol. Survey Geol. Atlas, Franklin Furnace folio (No. 161), p. 

9, 1908.
CHAEACTERISTICS 7

cent of tungsten, although no tungsten mineral can be identified, and 

the tungsten is probably contained in the wulfenite, which thus 

approaches chillagite in composition.

Naturally, wulfenite deposits can be expected to extend only to 

ground-water level or slightly below.

Molybdite is an oxidation product of molybdenite and was long 

considered to be an oxide of molybdenum, but Schaller 11 showed 

that all specimens contain iron in definite proportions. Guild 12 

got the same results except that he found 7H2 0 instead of Schaller's 

7-|H2O. (See p. 2.) By itself molybdite has no commercial importance, but taken in connection with the molybdenite in such great 

deposits as that at Climax, Colo., it forms a considerable part of the 

ore, carrying in the upper part of the Climax ore body about onethird of the metal. 13 (See PL X.) It may be sulphidized and floated 

with the molybdenite. In some places molybdite collects in showy 

masses. It is fairly soluble in water and migrates rather readily.

Ilsemannite is a water-soluble blue mineral of uncertain composition, is found in few deposits, and has so far not proved to be 

of commercial importance. Hofer 14 described it as Mo2 .4Mo03 . 

Schaller 15 thought the mineral to be a hydrous sulphate. Yancey 16 

disagreed with both but was unable to suggest a formula that he 

believed would fit the mineral. That it is an oxide now seems to me 

the more likely. Ilsemannite is a rare mineral and has been noted 

at only a few localities. Deposits of ilsemannite at Ouray, Utah,17 

are large enough to have attracted some expenditure of capital.

Chillagite 18 is a yellow mineral with the appearance of wulfenite 

but with a composition between that of wulfenite (PbMoOJ and 

stolzite (PbW04 ). So far as known it has been identified only at 

Chillagoe, Queensland. As already noted wulfenite from Shultz, 

Ariz., carries 2 per cent of tungsten trioxide (W03 ) and perhaps 

part of it is chillagite.

Powellite 19 is a calcium molybdate usually formed from the alteration of molybdenite. (See PL III, A.) As formed thus it is in thin

11 Schaller, W. T., The chemical composition of molybdic ocher; Am. Jour. Sci., 4th 

ser., vol. 23, pp. 297-303, 1907.

12 Guild, F. N., The composition of molybdite from Arizona: Am. Jour. Sci., 4th ser., vol. 

23, pp. 455-456, 1907.

18 Haley, D. F., Molybdenite operations at Climax, Colo.: Am. Inst. Min. and Met. Eng, 

Trans., vol. 61, pp. 73, 75, 1920.

14 H6fer, H., Studien aus Karten : Neues Jahrb., 1871, p. 566.

16 Schaller, W. T., Ilsemannite, hydrous sulphate of molybdenum : Washington Acad, 

Sci. Jour., vol. 7, pp. 417-420, 1917.

10 Yancey, H. F., Ilsemannite: Chem. and Met. Eng., vol. 19, pp. 186-190, 1918.

17 Hess, F. L., Ilsemannite at Ouray, Utah : U. S. Geol. Survey Bull. 750, pp. 1-16, 

1923.

18 Ullman, A. T., A new mineral: Roy. Soc. New South Wales Jour. Proc., vol. 46, pt. 

2, p. 186, 1912. Smith, C. D., and Cotton, L. A., Crystal measurements of chillagite: 

Idem, pp. 207-217.

10 Melville, W. H., Powellite calcium molybdate; a nenv mineral species : Am. Jour. Sci., 

3d ser., vol. 41, pp. 138-141, 1891.
MOLYBDENUM DEPOSITS

white flakes having the shape of molybdenite foils. The type material, from the Peacock claim, in the Seven Devils district, 120 miles 

north of Boise, Idaho, was in small doubly terminated pyramidal 

crystals that were probaby formed in some other way. It contained 

10.28 per cent of tungsten trioxide (W03 ) and looked like scheelite.

PRODUCTION OF MOLYBDENUM ORES

The production of molybdenum ores in any particular country 

during any particular period is an indication not so much of the 

potential importance of the country's deposits as of the ease of working under the conditions existing at the time in the country. The 

use of molybdenum has not yet been large enough nor its necessity 

sufficiently well proved to bring about, except in the United States 

and possibly New South Wales, developments that would show the 

possibilities of low-grade but large deposits, as has been done in the 

gold and copper industries.

The world's production of molybdenum so far as it can be ascertained from available data is shown in the following table. It is to 

be kept in mind that 1918 was the final year of the war, when the 

demand had reached its climax, and that in the British possessions 

production proceeded during 1919 under the war impetus and a 

promise of the Government to take the product for six months after 

the war at an agreed price of 105 shillings per long-ton unit for 

concentrates carrying 90 per cent or more of MoS2 . In order to have 

a common basis of comparison, the metal contained in the ore is 

estimated.

The world's output of molybdenum ore, 1918-1921, in terms of the metal contained, in tons of 2,000 pounds

Country

Australia:

New South Wales. _ . .............

Victoria.. ________ . ..........

Chile-----.- .....................

China.. __ - _ . _ ....... .............

Italy....................................

Ore

.....do........... ............

.....do.......................

.....do............ .

.....do................... .

... ..do.................. ..

.....do........ .... .... ... .

.....do ......... ... ..

.....do.......... ..........

..... do....... ..... ... ... ... ..

 ..do....,..... ..........

Wulfenite _______ . __

. ....do....... ........... .....

.....do............ ...........

... ..do........... ............

 do.................. .

1918

51.4

60.7

.1

.7

.8

113.4

19.3

( )

11.8

.7

.1

77.5

15.0

93.6

1.4

24.3

390.8

861.6

1919

0.4

36.3

64.9

.1

4.2

1.0

24.9

.3

< )

.1

.3

.1

4.5

1.1

34.1

2.5

.1

198.6

373.5

1920

22.0

15.4

2.6

67.7

2.4

(')

.5

50.3

3.2

.2 ( )

17.5

121.8

1921

4.4

3.0

(*> 0

.8

2.5

.9

.4

o No output recorded. 

]& Exports. 

J« Less than 0.1 ton.
UNITED STATES

MOLYBDENUM DEPOSITS

UNITED STATES -i

So far as present developments show, the United States possesses 

the largest known molybdenite deposits. It also has a rather large 

aggregate of wulfenite ores in the Southwest. Probably in every 

State that has outcrops of granitic rocks at least specimens of molybdenite can be found, and in a dozen States more or less serious attempts have been made to mine the mineral. (See fig. 1.)

1000 Miles

FIGURE 1. Principal molybdenum deposits in Canada, the United States, and Mexico. 

W, Wulfenite; IL, ilsemannite; the others are molybdenite. , Productive mine; O. 

mine from which little or no production has been made

The largest output of molybdenum has come from the great 

deposit at Climax, Colo., and from the Camp Urad deposit, 

11 or .12 miles up Clear Creek (west) from Empire, Colo. Both 

produce molybdenite.

The Climax deposit has been described by Brown and Hayward,20 

Haley,21 Holland,22 Horton,28 and Worcester.24 It is 15 miles north20 Brown, H. L., and Hayward, M. W., Molybdenum mining at Climax, Colo.: Eng. and 

Min. Jour., vol. 105, pp. 905-907, 1918.

21 Haley, D. F., Molybdenite operations at Climax, Colo.: Am. Inst. Min. and Met. Eng. 

Trans., vol. ,61, pp. 71-76, 1920 (read September, 1918).

22 Holland, L. F. S., Recent developments in molybdenum: Min. and Sci. Press Oct 19 

1918, pp. 529-531.

23 Horton, F. W., Molybdenum its ores and their concentration, with a discussion of 

markets, prices, and uses: Bur. Mines Bull. Ill, pp. 68-69, 1916.

24 Worcester, P. G., Molybdenum deposits of Colorado, with general notes on the molybdenum industry : Colorado Geol. Survey Bull. 14, pp. 87-94, 1919.
10 MOLYBDENUM DEPOSITS

east of Leadville, at Fremont Pass (altitude 11,300 feet), in which 

lies the little village of Climax. The deposit lies a mile east of the 

village, at altitudes between 12,000 feet and 12,500 feet. Naturally 

at such an altitude in this latitude (about 39° 22' N., longitude 

about 76° W.25 )

The climatic conditions are severe, and snow can be expected during any 

month of the year. Winter sets in not later than November 1, the snowfall is 

very heavy, and the ground remains covered with snow until June 1, and sometimes even later. From June 1 to October 1 there is much rain, and a little 

snow falls in the late afternoon nearly every day. In October, 1917, there was 

one of the biggest snowstorms and blizzards of the year. Being just on the 

divide, constant strong winds blow the fine, dry snow with such force that, 

during most of the winter, outside work of any kind is accomplished under most 

trying conditions.

The locality is on a high, rough, bare mountain ridge, running 

nearly north and south. A glacial cirque a mile long and half a 

mile wide is cut in the west side of the ridge and opens to the northwest at Fremont Pass. The mountain on the northeast side of the 

cirque is called Bartlett Mountain, and that on the southwest side 

Ceresco Mountain. A small stream drains the cirque, and along it 

on both sides, but especially on the slope of Ceresco Mountain, is a 

great accumulation of heavy debris.

Within the cirque on the lower slope of Barlett Mountain is the 

explored ore body, a huge mass of brecciated porphyry with granitic 

rocks of several kinds, in general rather quartzose, that seems to have 

a northwest elongation. However, it extends down to the creek, and 

above the wide band of debris on Ceresco Mountain many openings 

have been made on molybdenite-bearing outcrops that may be an 

extension of the same deposit, though the debris slope is too large 

to allow a definite correlation. If these openings, as believed by 

Worcester, are on the same ore body, then the greatest extension is 

about north and south. On the northeast side of the cirque the ore 

body is more than 1,000 feet wide from northeast to southwest and is 

at least 1,500 feet long from southeast to northwest and may be very 

much longer. All the molybdenum-bearing rock of consequence in 

this locality seems to be a part of this great ore deposit.

When the great size of the brecciated body is remembered, and 

when it is considered that the rock is not mashed, the thoroughness 

with which it is broken is wonderful. No uncracked piece containing 

as much as 2 cubic inches was seen in the main ore body. Solutions 

.from the magma flowed through every tiny crack, sericitized and 

silicified the broken rock, and filled the cracks with quartz. As the 

cracks were filled molybdenite was deposited in thin films in most of 

the tiny veinlets, while the flow of siliceous solutions continued. The 

total quantity of silica introduced into the deposit was enormous.

2B Haley, D. F., op. cit., p. 71.
UNITED STATES 11

On the deposit the Climax Molybdenum Co. owns a number of 

claims and the Molybdenum Products Corporation had one patented 

claim containing 5 acres. The following extract from the description 

by Brown and Hayward already cited applies to the ore on the holdings of both companies:

Erosion, due to climatic conditions, has been rapid and has kept pace with 

oxidation over practically all the mineralized area; sulphides of approximately 

the same grade encountered in the underground workings are exposed on the 

surface. * * *

The molybdenite values are remarkably uniform throughout the ore body.

In all the development work to date, amounting to over 5,000 feet, there have 

been no blank assays. In the mine workings, including those at a depth of 500 

feet from the surface, considerable amounts of yellow oxide of molybdenum 

are found. Mineralization is invariably confined to fractures, which have 

allowed oxidation to take place as a result of the circulation of surface waters. 

Apparently there has been little or no migration of the molybdenum deposition 

and therefore no concentration of values in a zone of enrichment.

No other minerals occur in the deposits, with the exception of a small amount 

of pyrite. [After this article was written specimens of wolframite were 

found. F. L. H.] Concentrates containing 75 per cent molybdenum sulphide 

show less than 0.1 per cent copper, the analysis showing, besides the molybdenite, only insolubles and iron. The ore body is apparently terminated on 

the northeast by a regular fault dipping 60° NE., but while the present opinion 

is that this fault is the limit of the ore body, this conclusion has not yet been 

proved.

Development work of the Climax Molybdenum Co. has been confined to an 

area of 25 acres of patented ground, although the company holdings comprise 

in all more than 600 acres.' From the mouth of the tunnel back to the fault 

an area approximately 1,000 by -800 feet has been completely blocked out and 

contains over 6,000,000 tons, averaging 1 per cent molybdenum sulphide. Another tunnel has been started 200 feet below these workings and shows ore of 

the same grade and character. Owing to the dip of the fault, the mineralized 

area of this tunnel probably will be nearly double that of the upper level, thus 

indicating the ultimate development of considerably more ore than now 

estimated.

The method of mining contemplated calls for a series of parallel stopes, 800 

feet long and 25 feet wide, with pillars between of the same width. The stopes 

will be carried as shrinkage stopes to the surface. After the shrinkage stopps 

are through to the surface it is planned to break the pillars down into these 

stopes. This method is to be adopted wherever a height of 200 feet will carry 

the stopes to the surface, and where, owing to the contour, it is less than this 

distance to the surface, the idea being to drive a series of parallel drifts and 

raises to the surface and glory hole from the surface to the drifts on the tunnel 

level.

Surface mining can be carried on only during four months of the year, for 

while commercial ore outcrops on the surface, with no overburden, the climatic 

conditions are such that a scheme of mining had to be outlined which would 

permit underground work during that part of the year when the surface could 

not be attacked. The ore is ideal for shrinkage stopes, as it contains no talc 

and breaks short.

The ore now mined from the upper adit is delivered to bins at the mouth 

of the tunnel and then carried 500 feet down the mountain by means of a
12 MOLYBDENUM DEPOSITS

two-bucket tramway to the crusher plant. The elevation of the lower tunnel 

is the same as that at the crusher plant, and it is planned to eventually bring 

all of the ore down to this level and to do away with the two-bucket tramway.

Haley,26 who wrote at a later date, says that the ore as fed to 

the mill carried 0.92 per cent of molybdenite, estimating all the 

molybdenum as MoS2. However, there is really present 0.25 to 0.3 

, per cent of molybdenum trioxide (Mo03 ) contained in molybdite. 

The ore contains about three times as much pyrite as molybdenite. 

About 82 per cent of the molybdenite in the ore was saved, and before 

the plant was closed sulphidation and flotation of the molybdite was 

accomplished.

The Climax Molybdenum Co. first erected a mill capable of handling 300 tons of ore a day and increased it to handle 1,000 tons a 

day. The Molybdenum Products Corporation built a 300-ton plant. 

Both also erected headquarters houses and other buildings, and 

both put up aerial tramways.

The Pingrey Mines & Ore Reduction Co. has claims on Ceresco 

Mountain and according to Worcester 27 has " demonstrated beyond 

any question that the ore continues across from Bartlett Mountain 

to the west slope of Mount Ceresco. * * * The country rock> 

fracturing, occurrence, and values of the ore seem to agree closely 

with those on Bartlett Mountain."

The origin of the ore is probably connected with the intrusion of 

a quartz porphyry, now so altered by sericitization and silicification 

as to be difficult of differentiation from the granites, large volumes 

of which are also altered in the same manner. Owing to the altered 

condition of the rock it is not possible to prove that this is or is not. 

one of the porphyries described by Emmons,28 but it is probably a, 

dike form of the rhyqlite he described.29 That it is not the ordinary 

granite of the region is shown by the sparse, rounded grains of 

quartz. (See PI. II.) It is not unusual to find molybdenite accompanying intrusive rhyolite.

On Red Mountain, at the head of Clear Creek, in Clear Creek 

County about1 35 miles northeast of Climax and 12 miles west of 

Georgetown, is Camp Urad, at which is the molybdenum mine opened 

and for several years operated by the Primes Chemical Co. but now 

belonging to the Vanadium Corporation of America. This mine has 

been one of the largest producers of molybdenum and has been described by both Horton 80 and Worcester.31 The principal workings,

48 Haley, D. F., op. cit., p. 75. 

87 Worcester, P. G., op. cit., p. 9-1.

28 Emmons, S. F., Geology and mining industry of Leadville, Colo.: U. S. Geol. Survey 

MOD. 12, Atlas, p. 6, 1886.

29 Emmons, S. F., U. S. Geol. Survey Geol. Atlas,, Tenmile district special folio (No. 

54), p. 3, 1898.

80 Horton, F. W., op. cit, pp. 66-67.

81 Worcester, P. G., op. cit., pp. 47-50.
UNITED STATES 13

though in unsurveyed land, are probably in sec. 29, T. 3 S., R. 75 W., 

and are at an altitude of about 11,300 feet; the camp is at 10,200 

feet. From the descriptions given the mine seems to be on a sheared 

zone 200 feet wide, striking N. 65° W., in which are granite and 

nlaskite( ?) porphyry. In this zone are quartz veins carrying molybdenum and pyrite. The veins range from a small fraction of an inch 

to 3 or 4 feet across, and there is some ore-bearing breccia. The 

molybdenite is altered to molybdite near the surface, and the ore is 

said to be wholly free from copper. The rock is fairly soft and is 

apparently more or less sericitized. Horton says that the ore averaged approximately 2 per cent of molybdenum, but it is reliably reported as carrying only 0.5 to 0.6 per cent. Coghill and Bonardi 82 

simply say that it " is of about the same grade as that of other workable molybdenite deposits." As to the size of the molybdenite particles they say, " The molybdenite ranges in size from large beautiful specimens to the minutest specks firmly locked in the siliceous 

gangue." Data as to the quantity of ore developed or in reserve are 

not at hand.

There are many other molybdenite deposits in Colorado, from 

several of which some production has been made.

NEW MEXICO

Seven miles east of Questa, N. Mex., just south of the Colorado State 

line and a short distance east of the Rio Grande, the Molybdenum 

Corporation of America, successor to the R & S Molybdenum Co., has 

a rather extensive molybdenite deposit that in its general features 

seems to be of the same type as the deposit at Camp Urad, Colo. It 

has recently been described by Larsen and Ross.33 The grade of the 

ore is very much higher than that of the Climax ores, but the quantity is much less.

ARIZONA

In Arizona some ore has been produced from claims in Copper 

Canyon, about 25 miles southeast of Yucca. Copper Canyon drains 

southeastward in a trough about 3 miles long that has been cut longitudinally in the east side of the Hualpai Mountains and joins, 

at nearly right angles, Deluge Wash, which slopes eastward to Big 

Sandy River.

Beginning with the claims of the Arizona Molybdenite Consolidated, which are just across the narrow divide (north) from the head 

of Copper Creek, a succession of groups of claims held for molybdenum extends to Deluge Wash and spreads both up and down the

82 Coghill, W. H., and Bonardi, J. P., Flotation of molybdenite at Empire, Colo.: Eng. 

and Min. Jour., vol. 109, p. 1210, 1920.

33 Larsen, E. S., and Ross, C. S., The R & S molybdenum mine, Taos County, N. Mex.: 

Econ. Geology, vol. 15, pp. 567-573, 1920.
14 MOLYBDENUM DEPOSITS

wash. Nearly all the workings are on the east side of the Copper 

Creek canyon and are on quartz veins cutting granite. The veins are 

all similar in character and differ only in size and richness. They 

were deposited near the surface of a granitic intrusion as comparatively pure white quartz, probably with a small quantity of pyrite, 

chalcopyrite, sphalerite, and galena and possibly some molybdenite. 

Movement along the veins continued, the quartz was broken, and in 

cracks molybdenite and more pyrite and chalcopyrite were deposited.

The Leviathan Mines Co. has been the largest operator and has 

a mine in Copper Canyon, about a mile from Deluge Wash. The 

company had sunk a shaft 220' feet deep on the Leviathan vein, a 

prominent quartz vein that crosses from one side of the canyon to 

the other and is as much as 20 feet but in most places is probably 

nearer 7 feet wide. The shaft, following the vein, has an inclination 

of 8 feet in 100 feet. Water was so scarce in 1917, when the mine was 

last operated, that the mill could run only two shifts a day, although 

a pipe line had been run 4 miles to a point in Deluge Wash, from 

which it was expected a plentiful supply would be obtained, but it 

gave out in August. Water was obtained from the shaft, but a strong 

taste of pine oil in the water showed that it was receiving the drainage 

from the mill. Counting the back flow, the shaft was furnishing 

about 5,000 gallons of water a day. The ore carried about 1 per cent 

of molybdenite, nearly as much copper in chalcopyrite, arid less 

pyrite. Low-grade concentrates carrying 20 to 30 per cent of molybdenite and 18 to 25 per cent of copper were made by oil flotation. No 

pay was received for the copper in the concentrates. Several hundred 

feet of drifting had been done on the 100-foot level, and a considerable quantity of ore had been broken down on the stulls when I visited the mine in 1917.

There are many other molybdenite-bearing outcrops in the Hualpai 

Mountains, on some of which considerable work has been done and 

a small production made.

Molybdenite has been mined at Helvetia, Ariz.,34 where it is found 

in both contact-metamorphic deposits and quartz veins cutting preCambrian granite and associated with aplite; and at Duquesne 

and San Antonio Canyon, where it occurs in altered granite porphyry 

and altered granite, respectively.

OTHER LOCALITIES

In Alaska a deposit at Shakan, in the northwestern part of Prince 

of Wales Island, has been developed by the Alaska Treadwell Co. 

It is in a mineralized shear zone in hornblende diorite, 600 feet above 

Shakan Bay.35 The zone crops out for 500 feet. The ore averages

s*Schrader, F. C., and Hill, J. M., Some occurrences of molybdenite in the Santa Rita 

and Patagonia mountains, Ariz.: U. S. Geol. Survey Bull. 430, pp. 154-163, 1910.

38 Mertie, J. B., jr., Lode mining in the Juneau and Ketchi'kan districts: U. S. Geol. 

Survey Bull. 714, pp. 118-119, 1921.
UNITED STATES 15

from 1 to 2.28 per cent MoS2 in large lots; 6,270 tons of the highgrade ore was blocked out, and 100,000 tons of ore assaying 1.58 per 

cent was indicated.38

A little molybdenum ore has been mined from contact-metamorphic 

deposits near Bishop, Calif., and Golconda, Nev. Attempts to mine 

molybdenite have been made at many other places in this country, in 

California, Idaho, Maine, Montana, Nevada, Oregon, Texas, Utah 

(Alta), and Washington, probably without profit.

Wulfenite has been produced mostly from the old Mammoth mine, 

at Shultz, Ariz., about 40 miles north of Tucson. The mine was 

first worked for gold. The ore was transported to Mammoth, on San 

Pedro Kiver, 3 miles away, where it was treated by crushing and 

amalgamation. Some years later the tailings were treated by cyanidation, and still later they were run through sluice boxes to save the 

wulfenite. The ore had been so' finely crushed that the friable particles of wulfenite were too small to be easily saved in this manner, 

but some concentrate was obtained. The tailings were spread over 

a considerable area of ground and lay so long undisturbed that they 

had been in part farmed as if they were soil. E. 0. Boykin then 

sampled and later, with Frank H. Hereford, bought them, formed 

the Arizona Eare Metals Co., and erected a mill in which they were 

treated. After all these handlings a little wulfenite still remained 

in the tailings, and they were being treated by sulphidation and flotation when the armistice was signed and work had to stop for lack 

of market.

In 1916 the Mammoth mine, which had long lain idle, was taken 

over by Col. Epes Eandolph and associates under the name Mammoth Development Co., and work on it was begun. The mine had 

been worked down to about 760 feet somewhat below water level. 

With the Mammoth, the Collins mine, a few hundred feet west, was 

also purchased. The mines are in brecciated zones, 10 to 20 feet 

across or even wider, in granite and later porphyries. The broken 

rock is loosely cemented, and in the cracks are wulfenite crystals. 

With the wulfenite is some vanadinite, descloizite, cuprodescloizite, 

and, in the Collins mine, considerable cerusite and some copper 

carbonates. The wulfenite is yellow, brownish yellow, carrot-red, 

brownish red, and bright red. The crystals bristle from the fragments of the breccia, so that the light from a lamp is reflected from 

thousands of facets, giving the appearance of myriads of tiny 

flames. The stopes hold up almost without timber, even though so 

loosely cemented. Not nearly so much work has been done in the 

Collins mine as in the Mammoth mine.

88 Bradley, F. W., Min. and Scl. Press, vol. 117, p. 48, 1918.
16 MOLYBDENUM DEPOSITS

A few hundred feet east of the Mammoth mine the old Mohawk 

mine, also worked for gold, reaches a depth of about 700 feet. 

The surface is here considerably below that at the Mammoth and the 

Collins. The Mohawk has lain idle for years. Several of the upper 

levels have large stopes with thousands of tons of broken ore ready 

for removal, but apparently too lean in gold to be worked for that 

metal. The stopes have the same beautiful appearance in the lamplight as those of the Mammoth, but they appear from inspection 

without sampling to be less rich and to contain a larger proportion 

of vanadinite. The mine has not yet been worked for these minerals,, 

but the appearance of the stopes suggests the possibility of drawing 

the broken ore at a profit, even if no other work could be doner 

provided, of course, that a market could be found for the concentrates.

Although no tungsten mineral has yet been identified in these 

mines, the concentrates are said to carry as much as 2 per cent of 

tungsten trioxide.

Among the numerous other wulfenite-bearing mines in Arizona 

one at Pantano has made some production, but most of them are 

very much smaller. Some wulfenite is found also near Lavic and 

at other places in California and at Eureka and other places in 

Nevada, and some has been produced at Organ, N. Mex.

CANADA

Canada, like the United States, has many deposits of molybdenite. (See fig. 1.) In 1911 the then known deposits were well described by Walker,87 but since that time many deposits have been 

found and deposits known before have been given an entirely different complexion through active development. By far the largest 

deposit now known is that opened in the Moss mine of the Dominion 

Molybdenite Co. (Ltd.), 3 miles north of Quyon, Quebec. The mine 

is also known as the Wood mine 88 because of its part ownership by 

Henry E. Wood. Camsell 80 and Wilson,40 each of whom has described the deposit, agree on most details.

A pink fine-grained hornblende-quartz syenite is intruded into aL 

older porphyritic gray syenite and is itself cut by pegmatite and aplite dikes. There are a number of ore bodies in a zone 500 feet long. 

60 feet wide, and at least 250 feet deep. The largest ore body is 50>

37 Walker, T. I/., Report on the molybdenum ores of Canada, 64 pp., illus., Canada Dept. 

Mines, Mines Branch, 1911.

88 Dresser, J. A., A note on the Wood molybdenite mine near Quyon, Quebec: Canadian 

Min. lust. Bull. 59, pp. 206-208, 1917.

88 Camsell, Charles, Molybdenite deposits of the Moss mine, Quyon, Quebec: Canada 

Geol. Survey Summary Kept, for 1916, pp. 207-208, 1917.

40 Wilson, M. E., Molybdenite deposits of Quyon district, Quebec: Canadian Min. Jour, 

vol. 39, pp. 78-80, 1918; Molybdenite in the lower Ottawa Valley: Canadian Inst. Min. 

and Metallurgy Bull. 192, pp. 749-754, 1920.
CANADA 17

ieet wide, 200 feet long, and 75 feet deep. The deposits all have an 

elongated form and are made up of masses of granular quartz, feldspar (chiefly gray or greenish-gray microcline), pyrite, pyrrhotite, 

fluorite, magnetite, limonite, and molybdenite. The ore is mostly 

medium grained and of granitic appearance but is in places coarse 

and pegmatitic, and black pyroxene crystals are locally abundant 

and in part radially disposed. Pyrite occurs usually in cubes. The 

molybdenite and other sulphides in lean ore are commonly distributed in zones parallel to the longer dimension of the deposit.41 Camsell thought the deposits to be pegmatites, but Wilson thinks that 

they are due to magmatic segregation. From the descriptions they 

seem very similar to deposits in other countries that have ben determined as pipes or other deposits formed by the replacement of 

granitic rocks. Hand-picked ore carried as much as 6 per cent of 

molybdenite, but Wilson thought that the ore in the bottom of the 

open pit on the largest deposit did not carry more than 0.75 per cent 

and that of the next largest deposit 0.5 per cent. Other mines in 

Quebec are described by Gwillim 42 and Mailhiot.48

In eastern Ontario there are numerous molybdenite deposits, but 

their mode of occurrence " is such that a person reading the ordinary 

descriptions of the occurrence of this mineral would be likely to 

look in almost any other place than where it is likely to occur," 44 

for nearly all the deposits are of contact-metamorphic origin,45 having been formed where pegmatite, granite, or syenite has cut the 

Grenville limestone. The deposits carry large quantities of green 

pyroxene (diopside) and considerable scapolite, pyrrhotite, and 

pyrite.40 The principal mine is that of the Renfrew Molybdenum 

Mines (Ltd.). An ore body has been traced 100 feet on the surface, 

and another one at a depth of 100 feet is 10 to 15 feet wide and carries 1 per cent MoS2. The ore bodies are apparently as erratic as 

most other contact-metamorphic deposits.

During the war some molybdenite was produced by a number of 

mines in other districts of Canada, among which was the Molly 

mine, on Lost Creek, in the Nelson mining division, 15 miles from 

Salmo, B. C.4T This mine is on stockworks and impregnation deposits in intrusive granite near its contact with slate and limestone,

41 Wilson, M. E., unpublished manuscript.

43 Gwillim, J. C., Molybdenite in Nova Scotia, Quebec, Ontario, and British Columbia: 

Canada Munitions Resources Comni. Final Kept., November, 1915, to March, 1919, pp. 

108-133, 1920.

43 Mailhiot, A., Molybdenite deposits of Lacoine Township, Abitibi, Province of Quebec, 

Canada: Min. Jour., vol. 41, pp. 135-138, 1920.

44 Parsons, A. L., Molybdenite deposits of Ontario: Ontario Bur. Mines Twenty-sixth 

Ann. Kept., p. 275, 1917.

46 Ellis Thomson (A pegmatitic origin for molybdenite ores: Econ. Geology, vol. 13, 

pp. 302^313, 1918) believes that these ores have a pegmatitic origin.

46 Wilson, M. E., private communication. I have to thank Mr. Wilson for courteously 

correcting the section on Canadian molybdenum deposits.

47 Drysdale, C. W., Notes on the geology of the Molly molybdenite mine, Lost Creek, 

Nelson mining division, B. C.: Canadian Min. Inst. Trans., vol. 18, pp. 247-255, 1915.
18 MOLYBDENUM DEPOSITS

The granite is here closely sheeted and besides molybdenite carries 

pyrite and pyrrhotite. The ore zone appears to be about 10 feet 

thick, but blocky granite outside the sheeted ore zone is somewhat 

impregnated with molybdenite, and contact-metamorphosed sediments also carry some molybdenite, though not enough to be economically valuable. Shipments of ore ran as much as 16.59 per 

cent of molybdenite, and several thousand tons was thought to carry 

about 4 per cent. There are many other deposits in British Columbia,48 Nova Scotia,49 and Manitoba.50

MEXICO

Little has appeared in print about the molybdenum deposits of 

Mexico (see fig. 1), but it is known that molybdenite ores in small 

quantity from Lower California have been treated at Nogales, Ariz., 

and molybdenite ores from Nacozari have been treated by the American Smelting & Kefining Co., at El Paso, Tex. The International 

Commission Co., of Douglas, Ariz., mined molybdenite 20 miles east 

of Nacozari and had it milled at Nacozari.

George Fast, of Douglas, Ariz., has mined molybdenite near La 

Trinidad, in the Sahuaripa district, Sonora. The ore is said to be 

in a pegmatite, but the appearance of specimens suggests that the ore 

body is a pipe, and some masses of very pure molybdenite that 

weighed 100 or 200 pounds apiece have been extracted. Considerable 

masses of scheelite are associated with the molybdenite. The ore 

mined was so rich that during the period of high prices Mr. Fast 

was able to make "a profit after transporting it on pack mules 225 

miles through the mountains to the railroad at Nacozari.

The Colorado mine, at La Colorada, Sonora, has, according to one 

estimate, 1,000,000 tons of ore carrying 1 per cent of wulfenite left 

in the pillars and walls, but the accuracy of the estimate is unknown.

Near Tinaj as, Chihuahua, the Madero estate has a mine in which 

considerable quantities of wulfenite are associated with vanadinite.

VIRGIN GOBDA

Some molybdenite is reported to have been mined in connection 

with copper from a granite mass on Virgin Gorda Island, in the 

Caribbean, one of the Virgin Islands owned by Great Britain (see 

.tig. 2), but few details are at hand.

43 Gwillim, J. C., Molybdenite in Nova Scotia, Quebec, Ontario, and British Columbia : 

Canada Munitions Resources Comm. Final Kept., November, 1915, to March, 1919, pp. 

108-133, 1920.

48 Hays, A. O., Investigations in Nova Scotia : Canada Geol. Survey Summary Kept, for 

1917, p. 28-F, 1918.

60 De Lury, J. S., Molybdenite at Falcon Lake, Manitoba: Canadian Min. Jour., vol. 38, 

pp. 360-462, 1917. Bruce, E. L., Molybdenite near Falcon Lake, Manitoba: Canada Geol. 

Survey Summary Kept, for 1917, pp. 22-25, 1918.
MOLYBDENUM DEPOSITS 

PERU

19

Peru produced from 2.7 to 7 metric tons of molybdenum ore 

annually in the years 1913 to 1918, inclusive.61 It was concentrate 

" laboriously picked by hand from superficial workings " in the department of Lima; the Cajatambo district, Ancachs; and the Prov500 1000 Miles

FIGURE 2. Principal known molybdenum deposits of South America and the West Indies. 

All the known deposits carry molybdenite

ince of Huari; and some concentrates made by a small plant at 

Ricran, near Jauja, Junin. (See fig. 2.) Small quantities have been 

produced at other times in the departments of Huanuca and Cuzco. 

The deposits in Ricran are said to be very large but must be worked 

by machinery to give large yields.52 They are 18 miles (30 kilo61 Jiminez, C. P., Estadlstica minera en 1918: Cuerpo ing. minas Peru Bol. 96, pp. 134- 

135, 1920. 

63 Idem, 1917 : Bol. 95, pp. 219-220, 1919.
20 MOLYBDENUM DEPOSITS

meters) northwest of Jauja and are molybdenite-bearing quartz 

veins cutting granite. The average content is said to be 2 to 3 per 

cent MoS2 , and they are claimed to be among the largest deposits 

in the world,53 to be easy to work, and to concentrate at low cost.

BOLIVIA

A little molybdenite has been produced in Bolivia by arduous 

hand picking, but no deposits offering effective competition to the 

large North American deposits are known to exist.

CHILE

Comparatively small quantities of molybdenite have been produced at Cupane, near Tacna, in the northern part of Chile,54 and 

occurrences have been reported in other parts of the country, but 

no large deposits are known. (See fig. 2.)

AUSTRALIA

All the States of Australia except Tasmania have produced some 

molybdenite, but by far the largest part has come from the States 

along the eastern coast Queensland, New South Wales, and Victoria. 

(See fig. 3.) South Australia, Western Australia, and Northern 

Territory have so far produced only small quantities, and at present 

there seems to be little promise of large production from any of them, 

for South Australia is lacking in known deposits of large size, and 

in the other two the deposits seem to be of modest size and transportation is a serious problem. None of the deposits so far described are 

comparable in size with that at Climax, Colo.

QUEENSLAND

Queensland has many deposits of molybdenite, with which are commonly associated wolframite and bismuth. All the deposits are 

either within intrusive granite or in the adjacent country rock. A 

number of the deposits of commercial value are in pipes, some are in 

veins, and others are in rocks called " greisen " that much-abused 

term which is commonly used to cover all sorts of altered granitic 

rocks. Queensland was a steady producer of molybdenite from 1900 

until 1920, when the British Government's war control of the industry 

ceased and, as in all other parts of the world, demand stopped and 

the mines had to close.

63 Jiminez, C. P., Estadfstlca minera en 1916: Cuerpo ing. minas Perti Bol. 94, p. 136, 

1917.

64 Ossa, J. D., Deposito de mollbdeno i tungsteno de Campanani, Arica: Soc. nac. 

minerla Bol. 223, vol. 28, pp. 203-213, 1916.
AUSTKALIA 21

The largest molybdenite producer at present is the Wonbah mine, 

near Wonbah, not far from the crossing of the parallel of 25° S. 

and the meridian of 152° E. As described by Keid,BB

The ore deposit is a white quartz pipe in granite, which for its size and 

regularity must be unique in Australian occurrences. The shaft is down a

U S Tj R A j :ALL/£ SOAK I

FIGURE 3. Principal known molybdenum deposits of Australia and Asia. All the known 

deposits carry molybdenite. The positions of Stanthorpe and Kingsgate are indicated 

too far north, as the State line runs between them

vertical depth of 180 feet, and the pipe, which is approximately cylindrical, 

appears to be increasing in size, as at No. 1 level its diameter was about 42 

feet, and at No. 2 level, at a vertical depth of 160 feet, it has increased to 

58 feet. So far as penetrated, the pipe is not at all tortuous and appears

M Reid, J. H., Wonbah molybdenite mine: Queensland Govt Min. Jour., vol. 20, p. 

465, 1919.
22 MOLYBDENUM DEPOSITS

to have a regular inclination of about 10° to 20° from the vertical. The 

whole pipe practically consists of white quartz, with which there is a good 

deal of calcite, especially in segregations. The occurrence of the molybdenite 

is less sporadic than is usual in similar pipes in this State and New South 

Wales and appears to be more concentrated toward the outer periphery of 

the pipe. Thus they are working a face 16 feet wide around the outer 

periphery, leaving a central core about 25 feet through, which is relatively 

poor. This working face shows molybdenite rather regularly scattered 

through it. The ore is clean, and so far there have been no metallurgical 

difficulties. In the face of the central core some small masses of other 

sulphides were seen in a calcite gangue. These consist of chalcopyrite, 

pyrite, galena, and zinc blende. Up to the present they have not been a 

source of trouble to the flotation of the ore, and as they occur more or less 

segregated, no trouble is anticipated.

In 1918, according to Reid, 2,435 tons of ore gave 13.95 tons of 

concentrates, valued at £6,052, and in the first nine months of 

1919 4,068 tons of ore gave 28.15 tons of concentrates, valued at 

£12,285. The entire output for the year was 38 long tons of concentrates, valued at £16,400.58

Among the principal molybdenite-bearing districts are those at 

Wolfram, Bamford, and Khartoum (formerly Sandy Tate), in the 

Chillagoe mining field, northern Queensland, between 17° and 18° 

south latitude and 144° and 146° east longitude. Other producing deposits are at Kidston, in the Etheridge gold field (19° south 

latitude, 144° east longitude); Ollera Creek, in the Star River 

mineral field, near Townsville (19° south latitude, 145° east longitude) ; and Stanthorpe, near the New South Wales border (28° 39' 

south latitude, 151° 58' east longitude).57 Mineralogical occurrences are of course numerous through the whole length of the 

eastern coastal belt, which contains many granitic intrusions. 58

The camp at Wolfram is on the edge of a granodiorite mass 

adjoining Paleozoic porphyry and slate, into which it has been intruded. The ore deposits are quartz pipes in the granodiorite, and 

the location of the pipes has been fixed by the intersection of joints.59 

Around the pipes the granodiorite is greisenized that is, changed 

to a mixture of quartz and mica. The pipes are extremely irregular 

in dip and range from less than a foot to 20 feet in diameter but 

average less than 5 feet. They have yielded principally wolframite 

but carry also molybdenite and bismuth minerals.

The largest of the pipes is on the Murphy & Leisner property, and 

from it 150 tons of wolframite, 100 tons of molybdenite, and 4

58 Queensland Govt. Min. Jour., vol. 21, p. 143, 1920.

67 Dunstan, B., Queensland mineral deposits a review of occurrences, production, 

values, and prospects : Queensland Govt. Min. Jour., vol. 17, pp. 314-316, 1916.

68 Ball, L. C., personal communication. I am under obligations to Dr. Ball for correcting the part of this paper that deals with Queensland.

68 Ball, L. C., The geology of Wolfram, N. Q.: Queensland Govt. Min. Jour., vol. 20, pp. 

509-511, 1919; vol. 21, pp. 6-11, 50-56, 1920.
AUSTRALIA £ 3

tons of bismuth were taken in three years.00 The average diameter 

of the working in the pipe was somewhat more than 20 feet. In 

general the pipes " are peculiar in shape, being typically bent and 

contorted." There appear to be many such pipes in the State,81 

but they are not large producers.

The Kitchener mine, at Khartoum, which has been one of the 

largest producers but is now idle, is on a mica-bearing quartz vein 

cutting granite. The vein contains no tungsten, bismuth, iron oxide, 

or iron or copper sulphides.02 - The molybdenite " occurs mostly as 

flakes, frequently displaying crystal outlines, and also as massive 

lumps and shotty pieces." At the time of his examination SaintSmith thought the lode averaged 4 feet 6 inches in width and that it 

would average between 3 and 4 per cent of molybdenite. Mining 

costs were estimated at £1 10s. a ton.

NEW SOUTH WALES

The coastal ranges extend from Queensland southward through 

New South Wales, and it is not surprising that this State also has 

numerous molybdenum deposits. Andrews 03 divides the deposits 

into five classes " pipes, pegmatite and aplitic segregations, pegmatitic veins, true quartz veins, and contact deposits." The largest 

deposits seem to be the contact-metamorphic deposits, though they 

have not yet produced much ore. The greatest production has heretofore come from pipes.

The largest contact-metamorphic deposits are around Mount 

Tennyson, near Yetholme, and at Gemalla and Tarana, a few miles 

east. They are a short distance east of Bathurst, not far from the 

point where the meridian of 150° E. crosses the Great Western Kailway (about 33° 30' south latitude), 125 miles, more or less, from 

Sydney. Here granitic rocks have intruded Paleozoic beds containing limestone, and masses of typical garnet-wollastonite tactite carrying molybdenite have been formed.04 The tactite is of remarkable 

extent. During the excitement over molybdenum caused by the 

demand incident to the war, several companies started rather extensive operations on the deposits.05 The Mammoth Molybdenite 

Mines, N. L., put up a mill and treated 4,424 tons of ore, from which 

it recovered 9 tons of concentrates. The grade is not given but was 

probably not over 90 per cent MoS2 , giving a recovery of less than

60 Ball, L. C., Rare-metal mining in Queensland : Queensland Govt. Min. Jour., vol. 14, 

pp. 4-6, 1913.

01 Dunstan, B., Queensland mineral index and guide: Queensland Geol. Survey Pub. 

241, pp. 748-750, 1913.

02 Saint-Smith, E. A., The Kitchener molybdenite mine, Khartoum: Queensland Govt. 

Min. Jour., vol. 18, pp. 226-229, 1917.

83 Andrews, E. C., The molybdenum industry in New South Wales: New South Wales 

Geol. Survey Mineral Resources No. 24, p. 26, 1916.

04 Idem, pp. 170-189.

08 New South Wales Dept. Mines Ann. Kept, for 1919. p. 56, 1920.
24 MOLYBDENUM DEPOSITS

0.2 per cent, although " a trial parcel * * * gave a return of 1.7 

per cent molybdenum disulphide." 66 The Mount Tennyson Molybdenite Mining Co. (Ltd.) also put up a mill, and the Broken Hill 

Proprietary Co. did a large amount of testing and drilling. The 

deposits have proved to be of too low grade to allow profitable 

exploitation under prices so far offered (105 shillings per long-ton 

unit for concentrates carrying 90 per cent or more MoS2 , c. i. f. London, was paid by the British Government during the Great War.

The best known and heretofore the most productive of the New 

South Wales deposits are pipes near Kingsgate, on the New England 

Plateau, 20 miles east of Glen Innes and probably less than 50 miles 

from Stanthorpe, Queensland. Glen Innes is on the Northern Kailway in about 151° 45' east longitude, 29° 45' south latitude. The 

pipes have been described by several writers, but best by Andrews,67 

who in 1916 68 listed 51 pipes at Kingsgate. The Department of 

Mines 69 in 1919 mentions 54 pipes on the property of Kingsgate 

Molybdenite, N. L. The pipes are tortuous irregular masses of 

quartz from 18 inches to 30 feet in diameter, as irregular in dip as 

in thickness, and have been followed as much as 350 feet. From the 

pipes irregular masses or " droppers " protrude. The pipes carry 

molybdenite, bismuth, and bismuthinite. In a few pipes arsenopyrite, a little wolframite, cassiterite, gold, and silver are associated 

with the molybdenite, and at various times .they have been worked 

unsuccessfully for the precious metals or for tin. One single piece 

of molybdenite found in Sach's or No. 45 pipe weighed more than 

a ton. The average content of the pipes is of course variable, and few 

data bearing on it are at hand. Forty tons of " rich stone "T0 from 

one pipe was expected to give 1£ tons of bismuth and molybdenite.

Similar pipes are found at Deepwater, Bolivia, and Rocky River, 

north of Kingsgate. At Whipstick, in the southeast corner of New 

South Wales, pipes also are worked. The pipes are large, and in 

some places several branch from a common root. They have manganiferous gossans, which Andrews considers to be derived from the 

alteration of garnet, and besides molybdenite carry mica, garnet, 

gold, silver, bismuth, bismuthinite, and joseite (telluride of bismuth).

New South Wales also has many lesser occurrences of molybdenite 

in veins, greisens, and other forms of deposits.

88 Molybdenite and wolfram : Chem. and Eng. Rev., vol. 10, p. 150, 1917.

87 Andrews, E. C., The geology of the New England Plateau, with, special reference to 

the granites of northern New England: New South Wales Geol. Survey Eec., vol. 8, pp. 

242-243, 1904-1907.

63 Andrews, E. C., The molybdenum industry of New South Wales: New South Wales 

Geol. Survey Mineral Resources No. 24, pp. 92-117, 1916.

80 New South Wales Dept. Mines Ann. Rept. for 1919, p. 56, 1920.

70 Andrews, E. C., The molybdenum industry in New South Wales: New South Wales 

Geol. Survey Mineral Resources No. 24, p. 114, 1916. I owe my thanks to Dr. Andrews 

for courteously correcting this section on New South Wales.
AUSTEALIA 25 

VICTORIA

Victoria has made only a negligible production of molybdenum, 

and not much had been published on the deposits before the Great 

War. Then, owing to the importance given to molybdenum ores 

by the sudden and insistent demand, the known deposits were examined by the Victoria Geological Survey, and in 1921 several short 

articles describing them were published.

After a study of the deposits Herman 71 concluded that those at 

Mount Stanley (near 146° 50' east longitude, 36° 30' south latitude), 

Mount Moliagul (near 143° 40' east longitude, 36° 45' south latitude), 

Simmons Gap (near 147° 30' east longitude, 37° 30' south latitude), 

and Everton (near 146° 30' east longitude, 36° 20' south latitude) 

were worthy of more prospecting than had been done on them.

All the deposits axe in granite near its contact with rocks into

which it was intruded and are more or less closely connected with 

quartz veins of various sizes. The deposits at Everton seem to be the 

most valuable, and during the war the Everton Molybdenite Mining 

Syndicate (which was succeeded by the Standard Molybdenite Mining Co., N. L.) and five other companies with capital ranging from 

£2,000 to £3,000 attempted to work them. TRe deposits are 2 miles 

north of Everton station on the Everton-Beechworth Railroad. 

Molybdenite has been found 72 over an area a quarter of a mile wide 

by 3 miles from north to south, in several granite bosses (probably 

protuberant from a single mass) intruded into slate and sandstone 

that seem to be of lower Ordovician age. The granite is cut by 

pegmatite dikes, but few of the dikes carry molybdenite, and in these 

it is accompanied by quartz. The molybdenite in the granite occurs 

with quartz veins, the largest of which is 1 foot thick. When examined by Kenny the main molybdenite-bearing body was in the 

Standard mine, near the north end of the area, and was dome shaped, 

the apex not cropping out, but coarse molybdenite was found near the 

surface, accompanied by molybdite. The dome was 27 feet across, 

roughly circular, and in concentric layers. In March, 1919, it had 

been proved to a depth of 23 feet. Finely disseminated pyrite accompanies the molybdenite. At the contact the slate is changed to 

hornfels, and a little molybdenite is found both in quartz veins cutting the rock and in the rock itself.

Half of the rock mined carried less than 1 per cent of molybdenite 

and was treated as waste. The other half was hand picked; one 

fourth of it carried 10 per cent and was shipped to Melbourne, and 

the other three-fourths, carrying 3 to 4 per cent, was piled. The

i Herman, H., Molybdenite occurrences In Victoria: Victoria Geol. Survey Rec., vol. 4, 

pt. 3, p. 203, 1921.

72 Kenny, J. P. L., The Everton molybdenite field : Victoria Geol. Survey Rec., vol. 4, 

pt. 3, pp. 295-299, 1921.
26 MOLYBDENUM DEPOSITS

total yield of the mine to March 28, 1919, had been nearly 42 short 

tons of ore, picked so that it carried from 7.3 to 10.53 per cent, 

valued at about $5,400 at normal exchange. Afterward a mill with 

a capacity of about 55( short tons a week was erected to treat ore 

carrying 1 per cent or more. From 280 short tons of ore 95.3 short 

tons of concentrates carrying 85 per cent is said to have been obtained.73 Such a result indicates remarkably rich ore.

At Mount Moliagul molybdenite is reported as occurring in a 

partly decomposed eurite or binary granite,74 and in less quantity 

in quartz veins. The Mount Moliagul Molybdenite Syndicate cut 

more than 2,000 feet of trenches 3 to 10 feet deep in a granite area 

measuring about 1,300 by 2,600 feet, but no production is reported, 

and no record has been found of the molybdenum content of the rock.

Smaller deposits have been prospected more or less seriously at 

Wangrabelle, Croajingolong. 75 Other small deposits are known at 

Maldon, Mount William, Kitchington Creek, Yea, Neerim, and other 

places.

SOUTH AUSTRALIA

In South Australia a few hundredweight of molybdenite has been 

obtained from the Yefta copper mine, at Moonta 76 (about 137° 5' 

east longitude, 34° 5' south latitude), on the Yorke Peninsula, east of 

Spencer Gulf, where it occurs with copper minerals and magnetite 

in a quartz vein cutting granite. 77 Molybdenite is also reported from 

a few other localities.78

WESTERN AUSTRALIA

Western Australia has produced only modest quantities of molybdenite, and though there are many occurrences, none seem to be 

very large. At Mount Mulgine (Warriedar) a gneissoid granite 

is impregnated with quartz and molybdenite. 79 There are " fair 

quantities " of ore carrying 1 and 2 per cent of MoS2.

Molybdenite deposits at Leonora, Callie Soak, Westonia, Swan 

View, and North Dandalup are noted by Simpson,80 Maitland,81 

and other workers on the Western Australian Geological Survey.

73 The Standard molybdenite mine, Everton, Victoria : Cbem. Eng. and Min. Rev., vol. 

12, pp. 448-449, 1920.

7* Baragwanath, w., Prospecting at the Mount Moliagul molybdenite mine, Mount Moliagul : Victoria Geol. Survey Rec. vol. 4, pt. 3, pp. 228-229, 1921.

76 Herman, H., Recent mining in Croajingolong: Victoria Geol. Survey Rec., vol. 4, pt. 

2, pp. 169-170, 1920.

76 South Australia Dept. Mines, Mineral resources for half year ended Dec. 31, 1917, p. 

!), 1918.

77 Brown, H. Y. L., Record of the mines of South Australia, 4th ed., p. 156, Adelaide, 

1908.

78 Idem, p. 368.

TO Blatchford, T., On the molybdenite occurrences at Mount Mulgine (Warriedar), YalMOO gold field: Western Australia Dept. Mines Ann. Rept. for 1918, pp. 77-78, 1919.

80 Simpson, E. S., The rare metals and their distribution in Western Australia: Western 

Australia Geol. Survey Bull. 59, p. 52, 1914.

81 Maitland, A. G., The molybdenite deposits of Western Australia: Western Australia 

Geol. Survey Mem. 1, chap. 2, pt. 3, sec. 7, 1919.
AUSTRALIA, NORWAY 27 

TASMANIA

Small deposits of molybdenite have been reported from various 

parts of Tasmania, but no production is known to have been made 

from them.

NORTHERN TERRITORY

Northern Territory has exported a few small lots of molybdenite, 

but transportation of ore and supplies is difficult and expensive, 

and if such deposits as that at Climax, Colo., existed in the Territory, it is not likely that they would pay for working. Only comparatively rich, easily separated ore can be handled profitably even 

when there is a market for molybdenite. At Yenberrie molybdenite 

is found in greisen with wolframite.82

NORWAY

Norway has been for years one of the principal producers of 

molybdenum ore. Most of the deposits are south of a line drawn 

west from Kristiania,83 in Lister, Mandals, and Stavanger amts. 

but the ore is also found in notable quantities in Nordlands Amt.84 

(See fig. 4.)

Before the Great War only two or three mines were actively 

worked, but on the beginning of hostilities the miners found themselves in a position to sell to both groups of contenders. Germany 

would take the product at very high prices; the Allies did not want 

Germany to have it, and to prevent sales1 to her agreed to buy all 

that was offered at $4 a pound for the contained MoS2 , though for a 

time the price was 26,250 kroners a metric ton for material carrying 

75 per cent of MoS2 , equivalent to about $4.25 a pound for the 

contained MoS2 . As Woakes 85 strikingly puts it, ore carrying 

0.5 per cent of MoS2 was as valuable as quartz carrying 2.75 ounces 

of gold ($56.84) to the metric ton. The established companies made 

undreamed of profits, and those who had or could obtain deposits, 

even poor ones, made haste to get rich while the prices born of desperation lasted, sinking shafts and erecting mills as feverishly as the 

climate and circumstances permitted, but when the armistice was 

signed many undoubtedly had not recovered their expenditures 

and lost money by the sudden termination of the demand. These 

high prices contrasted strongly " with the stories in those parts

82 Gray, G. J., and Winters, R. J., Report on the Yenberrie wolfram and molybdenite 

field: Northern Terr. Bull. ISA, 4 pp., 1916.

63 Woakes, E>. R., Molybdenum in Norway: Inst. Min. and Met. (London) Bull. 160, p. 

5, 1918.

84 Private communication from Prof. J. Schetelig, Kristiania, who was good enough to 

correct the section on Norway. See also Falkenberg, B. 0., footnote 88.

85 Woakes, E, R., op. cit., p. 2.
28 MOLYBDENUM DEPOSITS

about mountain peasants bringing ore over the mountain to Kristiansand and Stavanger, where they exchanged a pound of molybdenite for a pound of butter," the molybdenite being known as

;*V ^.

-^4 GERMA,NY"> POLAND/

FIGURE 4. Principal molybdenum deposits of Europe. For location of deposits at Bleiberg, Austria, and Meiss, Yugoslavia, see text. W, Wulfenite; the others are 

molybdenite. , Larger producer; O, smaller producer

" silver stone " and " lead-pencil stone " and used as a lubricant and 

for stove polish.88 

Claudet 8T quotes Falkenberg 88 on the geology as follows:

The most important discoveries in Norway are at Knabeheiem, near Kvinas 

Valley, north of Flekkefjord. The occurrences are associated with granite 

and partly granite gneiss. They appear to some extent in intimate association 

with massive pegmatite, and specially at the boundary of the pegmatite with 

the surrounding granite. In other places one can best speak of molybdenitebearing quartz rock, and finally there are occurrences of ore direct In the

88 Falkenberg, E. O., Norske molybdengruber: Teknisk Ukeblad, vol. 68, pp. 6-11, 1921; 

trans. in Eng. and Min. Jour., vol. Ill, pp. 1021-1023, 1921.

87 Claudet, H. H., Notes on molybdenite operations In Norway: Canadian Min. Inst. 

Trans., vol. 19, pp. 125-126, 1916.

88 Falkenberg, E. 0., Om molybdenmalmer deres forekomst, opberedning, anvendelse. 

etc.: Tidskrift Keml, Faraaci og Terapl, 1915.
NORWAY 29

granite without any accompanying kind of vein matter. This last is, however, 

of little extension and seems to be confined to small veins which intersect 

the granite. * * *

The ore-bearing zone is about 1 kilometer broad and has a longitudinal 

dimension from north to south of 20 kilometers. A further continuation is 

not out of the question.

Woakes 89 divides the deposits into (1) quartz lodes; (2) fissured 

granite, more or less decomposed, carrying molybdenite with little 

quartz, having a flat dip and little depth; (3) impregnated granite 

or norite. Some pyrite, chalcopyrite, a little pyrrhotite, feldspar,' 

mica, and hornblende are found with the deposits.

In the Knaben mine some of the stopes are 10 meters across, and 

although the molybdenite is in general finely disseminated, some 

large rich masses have been mined. In many places the ore disappears at shallow depths, either pinching out or leaving a barren 

vein,90 and Falkenberg thinks that this will prove generally true.91

On the Hovlands farm, Orsdal, Bjerkreim Parish, a little wolframite and scheelite are found with the molybdenite.92

The Dalen mine in 1917 produced 27,000 metric tons of rock, of 

which 8,000 tons was ore; from this was picked 2.4 tons carrying 

about 90 per cent of MoS2 , 4.8 tons carrying 70 per cent, and 9.4 

tons carrying 50 per cent. After picking, 38.4 tons of concentrates 

carrying 75 per cent of MoS2 and 48.9 tons carrying 65 per cent 

were obtained by the Elmore flotation process. The total content of 

the hand-picked and mechanical concentrates was 69.96 tons of 

MoS2 a yield of 0.875 per cent of the rock treated. 93

The ore of the Lille Knaben mine carried 0.39 per cent of MoS25 

and that of the Knaben mine No. 1 carried 0.56 per cent. The 

Knaben mine No. 2 had in sight 1,170,000 tons of ore carrying 0.5 

per cent of MoS2 .

The total Norwegian production to the end of 1920 is estimated 

by Falkenberg to have been about 8,800 tons of pure molybdenite.

There are many deposits in Norway that can be worked only 

under excessive prices or are of purely mineralogic interest.

Lloyd 94 says that wulfenite has been mined near Egersund, but 

this is apparently an error.95

88 Woakes, E. R., op. cit., p. 3.

"<>Claudet, H. H., op. clt, p. 126.

81 Falkenberg, E. 0., op. cit. (Teknisk Ukeblad), pp. 6-11.

92 Norges Bergverksdrlft, 1917, p. 55, Statistiska Centralhyra; 1918.

03 Idem, p. 16.

84 Lloyd, G. C., Report on the sources and production of iron and other metalliferous 

ores used in the iron and steel industry, p. 146, Advisory Council, Dept. Sci. and Ind. 

Research, London, 1918.

6B Personal communication from Prof. J. Schetelig.

94093 24 3
30 MOLYBDENUM DEPOSITS

SWEDEN

In 1918 the Udd mine, in Ljusnarsberg Parish, Orebrolan, Sweden 

(see fig. 4), produced 7,545 metric tons of rock from which 1,035 tons 

of ore carrying 36.4 per cent of MoS2 , valued at 10,920 kroner, was 

hand picked, and 6,045 tons carrying 0.77 per cent was concentrated, 

giving 73 tons carrying 55 per cent of MoS2 , valued at 1,069,260 

kronor.96

GERMANY

Some wulfenite has been mined in the Hollenthal, near Garmisch,97 

in southern Bavaria, close to the Austrian border. (See fig. 4.) 

The mineral occurs with galena in brecciated limestone. This deposit was worked for molybdenum during the Great War.

AUSTRIA

Several wulfenite deposits have been worked in Austria. (See 

fig. 4.) One deposit is near Nassereit,98 in the Tyrol, near the Swiss 

border, only 20 or 25 miles southwest of the German deposit at Garmisch. At Bleiberg, on the southeastern border, wulfenite has been 

known for many years. Both deposits furnished molybdenum to 

the Central Powers during the Great War. Mezica or Meiss, in 

Yugoslavia, is a few miles directly south of Bleiberg.

YUGOSLAVIA

At Mezica (Meiss or Meissdorf), 8 kilometers (5 miles) southwest 

of Prevaljo, Carniola, Yugoslavia, with which it is connected by a 

narrow-gage railroad, is a lead-zinc mine with a considerable quantity of wulfenite in the oxidized part.99 Before the Great War the 

mine was worked by the Kleiberger Bergwerks Union, but after the 

war it was sequestrated by the Yugoslavian Government.

Some of the deposits are lens shaped, 0.5 to 3 meters or more 

thick, 150 meters or more long, and 100 meters or more deep. Others 

are in chimneys or spirals, commonly with a horizontal section of 

only 4 to 9 square meters and reaching to depths of 30 to 40 meters. 

The associated minerals are quartz, calcite, barite, marcasite, pyrite. 

gypsum, and secondary minerals. There is no gold, silver, or anti88 Sveriges Offlciella Statistik, Bergshantering berattelse for ar 1918, pp. 92, 93, 96-97, 

1919.

87 Schmidt, C., Das Vorkommen von Gelbbleierz im Hb'llental bei Gormisch : Zeitschr; 

prakt. Geologie, vol. 23, pp. 93-102, 1915.

M Krusch, P., Ueber die Stellung des Gelbbleierzes (Wulfenit) in der Reihe der Leiterze 

im Lichte der im Kriege geschaffenen. Aufschlusse (Karnten, Werdenfels in Hollenthal, 

Dirstentritt bei Nassereit, u. s. w.) : Zeitschr. Berg-, Hutten- u. Salinenwesen preuss. St., 

vol. 66, Heft 1, pp. 56-69, 1918.

88 Smith, H. I., Index of mines in Slovenija, Technical Mission to the Serbs, Croats, 

and Slovenes, Reports on the mines of Slovenia, Sept. 5, 1920 (MS.).
SPAIN, JAPAX 31

mony. The ore bodies are in limestone or dolomite 1 cut by granite 

and basic dikes.

From 1902 to 1913, inclusive, there was produced 714 tons of 

wulfenite concentrates, said to carry usually about 27 per cent of 

molybdenum trioxide, but ranging from 26 to 34.18 per cent, with 

one small lot going down to 13 per cent. No figures for production 

during or since the war are available. At the time of Smith's visit 

TO tons containing 25 per cent of molybdenum trioxide was on hand. 

It was proposed to trade both lead ore and wulfenite to Germany 

for coke.

SPAIN

Some wulfenite has been produced near Quentar, in the Province 

of Granada, Spain,2 14 kilometers (about 9 miles) east of Granada. 

(See fig. 4.) A number of other mines, 12 to 20 miles south of Granada, also carry some wulfenite. In the Province of Almeria small 

deposits have been found near Oria. All are in limestones.

JAPAN

Few details are known of the Japanese molybdenum deposits. T. 

Hirabayashi 3 briefly outlined the occurrences as known in 1909, and 

according to his description molybdenite occurs in (quartz?) veins, 

pegmatitic veins, and contact-metamorphic deposits. The veins contain the most, and some carry wolframite and bismuth with the 

molybdenite. Veins in granite are known in the Provinces of Hida 

(about 36° north latitude, 136° east longitude), Bizen (about 34° 45' 

north latitude, 134° east longitude), and Idzumo (about 35° 30' 

north latitude, 133° east longitude), and contact-metamorphic deposits in Yechigo (given on some maps as Echigo and on others as 

Nigata, near 37° north latitude and 139° east longitude). (See

fig. 3.)

In 1917 Okura £ Co.4 wrote that the principal molybdenum mines 

of Japan were as follows:

Shirokawa mine, Shirokawamura, Oonogun, Toyama Province (given on some 

maps as Etchu; most of the province is between 36° 30' and 37° north latitude 

and 137° and 138° east longitude) ; output 500 catties (667 pounds) a month.

Miyamotomura, Kumagun, Toyama Province; output 250 catties (334 pounds) 

a. month.

Matsukawamura, Chikumagun, Shinano Province (near 36° north latitude, 

136° east longitude) ; output 250 catties (334 pounds) a month.

1 Granigg, B., and Koritschoner,. J. H., Die geologischen Verhaltnisse des Bergbaugebietes von Miess in Karnten : Zeitschr. prakt. Geologie, vol. 22, p. 172, 1914.

a Rubio, J. M., and Gavala, Juan, Yacimientos de mollbdeno en las provincias de Granada y Almeria: Inst. geol. Espaiia Bol., vol. 39, pp. 167-193, 1918.

8 Mining in Japan, past and present, pp. 111-112, Japan Bur. Mines, 1909.

* Cunningham, E'. S. (American consul general, Hankow, CMna), report to Sec. of 

State, Mar. 28, 1917.
32 MOLYBDENUM DEPOSITS

Tamatsukurimura, lyugun, Idzumo Province (near 35° 30' north latitude, 

133° east longitude) ; output 250 catties (334 pounds) a month.

In 1918 the Kogurobe mine, in Toyama, produced about 3.5 short 

tons of molybdenite, valued at about $6,500. 5 This was apparently 

the only mine that produced molybdenum ore to the value of 10,000 

yen.

CHOSEN

Some molybdenite has been mined in Chosen, but no descriptions 

of the deposits are known to have been published. In 1916 about 6.5 

tons, worth $2,500, was mined.6

CHINA

Prior to 1921 a little hand-picked molybdenite had been shipped 

from southern China, the whole amounting to only a few tons. It 

apparently was all obtained from the outcrops of quartz veins and 

" in fair to large sized chunks and flakes." In 1916 6,500 pounds was 

shipped from the districts of Yungfu (25° 14' north latitude, 118° 

51' east longitude) and Ningte (26° 34' north latitude, 119° 36' east 

longitude), Fukien Province (see fig. 3), through the port of Foochow, and during the first three months of 1917 5,600 pounds. No 

later reports have been obtained from these localities, but it was 

thought at the time that shipments would increase. 7

In 1917 small quantities were shipped from Hongkong to Great 

Britain and France and larger quantities to Canada for concentration and reexport to Great Britain. There seemed to be no question that the ore could be obtained in considerable quantities under 

similar market conditions, for it was just becoming known in the 

country, yet it had come in from a wide area. 8 It comes in part 

at least from quartz veins.

In 1921 it was reported 9 that 31,684 piculs (2,112 short tons) of 

" molybdenum," presumably molybdenite, was exported. No trace 

of this ore could be found in foreign trade, and none was recorded 

as exported from China in 1922. Inquiry among firms and individuals acquainted with the Chinese mineral industry disclosed 

no source for such a quantity of molybdenum ore, so that it seems 

probable that there may be some mistake in the figures.

6 The mining industry of Japan to 1918, p. 20, Japan Bur. Mines, 1919.

8 Miller, R. W. (American consul general, Keijo), report to Sec. of State, Apr. 13, 1917.

7 Pontius, A. W. (American consul, Foochow), report to Sec. of State, Apr. 20, 1917. 

8 Anderson, G. E. (American consul, Hongkong), Molybdenum in South China: Commerce Repts., Jan. 30, 1918, p. 390.

8 Foreign trade of China, 1921: China Maritime Customs, Statistical ser., Nos. 2-5, pt. 

1, p. 24, Shanghai, 1922.
SUMMARY 33 

TRANSVAAL

A few tons of molybdenite ore has been shipped from the Mutue 

Fides-Stavoren tin fields (about 24° 45' south latitude, 29° 25' east 

longitude), on the west side of Olif ants River a short distance north 

of its junction with the Elands, in Transvaal. The molybdenite 

occurs in pipes in granite.10 The pipes carry principally calcite 

and fluorite in their centers, with cassiterite, wolframite, arsenopyrite, bismuth minerals, raven mica (a black lithia mica), quartz, 

and other minerals between the core and the sericitized or greisenized walls. The molybdenite is particularly abundant in aureoles 

of raven mica surrounding some of the pipes.

OTHER COUNTRIES

Burma, Russia, Siberia, and other countries contain molybdenum 

deposits, but none of them arc known to have made any production 

of consequence.

SUMMARY

The world contains innumerable molybdenum deposits, mostly 

small, all of which, except in the oxidized parts, carry the metal, so 

far as is noAv knoAvn, in the form of molybdenite. Some of the molybdenite deposits, however, are extensive and contain large quantities 

of the metal. Wulfenite is of much less common occurrence, and 

the deposits are smaller and extend only as deep as the zone of 

oxidation. The form of the molybdenum below the oxidized zone 

is unknown. Molybdite is of value as an ore mineral only when 

mined with molybdenite, and deposits of other molybdenum minerals have not yet proved to be of commercial value. Compared 

with tungsten deposits there are many more occurrences of molybdenite, and the largest deposits are much larger than those of tungsten. A few, like those at Climax, Colo., and Yetholme, New South 

Wales, are very large, though of comparatively low grade, carrying 

only about 1 per cent or less of MoS2 , and it is likely that under 

the stimulus of a continuous demand a larger number of such deposits might be found. There are numerous areas where such developments would not be surprising, such as the mountain region extending from Mexico to Alaska; eastern Canada; Scandinavia; Siberia; the mountain region extending along the west coast of the 

Pacific from Tasmania to Siberia anywhere, in fact, that large 

areas of granite exist whose upper parts have not been deeply and

10 Wagner, T. A., The Mutuc Fidcs-Stavoren tin fields: Union of South Africa Geol. 

Surrey Mem. 16, pp. 127-128, 1921.
34 MOLYBDENUM DEPOSITS

generally eroded or, in other words, in the newly exposed granitic 

areas of the world. .

Whenever the world is ready to take molybdenum ores in large 

quantity at a price that will pay for extraction they will be produced. The United States has been the largest producer of molybdenum ores, and in the event of an absorbent market appearing, it 

is more than likely to be again the foremost in rank. What is the 

lowest price that will bring out the ores is hard to estimate, but 

it seems sure that if there were an open and continuous market for 

ores carrying 60 per cent of MoS2 at 50 cents a pound for the contained MoS2 several thousand tons a year would be forthcoming soon 

after it became apparent that the market was steady.
INDEX

ffage 

Alaska, molybdenum in....._............ 14-15

Arizona, molybdenum in.___ 5, 6,7,13-14,15-16 

Australia, molybdenum in_........... 5,7,20-27

Austria, molybdenum in.............. ... 30

Bolivia, molybdenum in_................. 3,20

Brown, H. L., and Hayward, M. W., cited.. 11-12 

Burma, molybdenum in_............... 33

California, molybdenum in................ 5,15,16

Camp Urad, Colo., molybdenum deposit at. 12-13 

Canada, molybdenum in...__........... 4,16-18

Ceresco Mountain, Colo., molybdenum in... 12 

Chile, molybdenum in....................... 20

Chillagite, occurrence of..................... 7

China, molybdenum in_................... 32

Chosen, molybdenum in..................... 32

Climax, Colo., molybdenum deposit at..... 7,9-12

Climax Molybdenum Co., operations by.... 11-12

workings of, plate showing._..... 7

Colorado, molybdenum in.............. 3,4,7,9-13

Distribution of molybdenum._............

Falkenberg, E. 0., cited.....................

Germany, molybdenum in..__.........

Granite replaced by molybdenum, plate 

showing..........._..........

Halcy, D. F., cited..........................

Idaho, molybdenum in.... 

Ilsemannite, occurrence of.

1-8

28-29

30

4

10

8,15

7

Japan, molybdenum in__................. 31-32

Maine, molybdenum in....

Mexico, molybdenum in_,

Minerals of molybdenum_.

Molybdenite, occurrence of.

plates showing..........

Molybdite, occurrence of....

Montana, molybdenum in..

4,15

5,18

2

2-6

4,5

7

5,15

 Page 

Nevada, molybdenum in.........___... 5,15,16

New Jersey, molybdenum in................ 6

New Mexico, molybdenum in........... 4,6,13,16

New South Wales, molybdenum in...__ 5,23-24 

Norway, molybdenum in.................... 27-29

Oregon, molybdenum in........_.......... 5,15

Outlook for molybdenum mining__...... 33-34

Peru, molybdenum in.... .____.__ 19-20

Powellite, altered from molybdenite, plate

showing__..................... 4

occurrence of................._.__.. 7-8

Production of molybdenum ore....._..__ 8

Quartz porphyry (?), carrying molybdenite,

plate showing ................ 4

Quartz porphyry breccia with a cement 

containing molybdenite, plate 

showing............_......... 4

Queensland, molybdenum in..._..._ 5,7,20-23

llcid, J. H., cited............................ 21-22

Russia, molybdenum in............._..... 33

South Australia, molybdenum in_......_ 26

Spain, molybdenum in......._............ 31

Summary of the report...................... 33-34

Sweden, molybdenum in.................... 30

Tasmania, molybdenum in........._...... 27

Texas, molybdenum in___....______ 15

Transvaal, molybdenum in.................. 5,33

Utah, molybdenum in.....................5,6,7,15

Victoria, molybdenum in.................... 25-26

Virgin Gorda Island, molybdenum on._... 18

Washington, molybdenum in_............ 4,15

Western Australia, molybdenum in.._.__ 26 

World's demand and resources, need for

knowledge of............. .... 1

Wulfenitc, occurrence of...---.-.-... 6-7 

plates showing___...--...--.......-... 6

Yugoslavia, molybdenum in... ... 30-31

35

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