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                          _IMPERIAL INSTITUTE_
                    MONOGRAPHS ON MINERAL RESOURCES
                     WITH SPECIAL REFERENCE TO THE
                             BRITISH EMPIRE


                  PREPARED UNDER THE DIRECTION OF THE
                  MINERAL RESOURCES COMMITTEE WITH THE
               ASSISTANCE OF THE SCIENTIFIC AND TECHNICAL
                    STAFF OF THE IMPERIAL INSTITUTE




                          THE PLATINUM METALS


                                   BY

            A. D. LUMB, A.R.S.M., F.G.S., Assoc. Inst. M.M.
 LATELY OF THE SCIENTIFIC AND TECHNICAL DEPARTMENT, IMPERIAL INSTITUTE

                               WITH A MAP

[Illustration]

                                 LONDON

                   JOHN MURRAY, ALBEMARLE STREET, W.

                                  1920




                          ALL RIGHTS RESERVED

------------------------------------------------------------------------




                           IMPERIAL INSTITUTE
                            MINERAL SECTION


The Imperial Institute is a centre for the exhibition and investigation
of minerals with a view to their commercial development and for the
supply of information respecting the sources, composition and value of
minerals of all kinds.

The Imperial Institute is provided with Research Laboratories for the
investigation, analysis and assay of minerals, and undertakes reports on
the composition and value of minerals, for the information of
Governments and producing companies and firms, in communication with the
principal users in the United Kingdom and elsewhere in the Empire.

Important minerals from within the Empire are exhibited in the
respective Courts of the Public Exhibition Galleries, and also in the
Mineral Reference Collections of the Institute.

A special staff is engaged in the collection, critical revision and
arrangement of all important information respecting supplies of minerals
especially within the Empire, new methods of usage and other commercial
developments.

Articles on these and related subjects are periodically published in the
_Bulletin of the Imperial Institute_, and monographs on special subjects
are separately published under the direction of the Committee on Mineral
Resources.




                           IMPERIAL INSTITUTE


                Advisory Committee on Mineral Resources

  The Right Hon. VISCOUNT HARCOURT, D.C.L. (_Chairman_).

  [A]Admiral SIR EDMOND SLADE, K.C.V.O., K.C.I.E. (nominated by the
      Admiralty), (_Vice-Chairman_).

  EDMUND G. DAVIS, Esq.

  [A]WYNDHAM R. DUNSTAN, Esq., C.M.G., LL.D., F.R.S., Director of the
      Imperial Institute.

  J. F. RONCA, Esq., M.B.E., A.R.C.S., Department of Industries and
      Manufactures (nominated by the Board of Trade).

  [A]Professor J. W. GREGORY, F.G.S., Professor of Geology, University
      of Glasgow, formerly Director of Geological Survey, Victoria,
      Australia.

  Sir ROBERT HADFIELD, Bart., F.R.S., Past-President Iron and Steel
      Institute.

  Captain A. L. ELSWORTHY, Intelligence Department, War Office
      (nominated by the War Office).

  W. W. MOYERS, Esq. (Messrs. A. Watson & Co.), Liverpool.

  R. ALLEN, Esq., M.A., B.Sc., Imperial Institute (_Secretary_).

Footnote A:

  Members of Editorial Sub-Committee


                            MINERAL SECTION

                       Principal Members of Staff


                            _Superintendent_

          R. ALLEN, M.A. (Cantab.), B.Sc. (Lond.), M.Inst.M.M.


                       _Assistant Superintendent_

                 S. J. JOHNSTONE, B.Sc. (Lond.), A.I.C.


                          _Senior Assistants_

                  G. M. DAVIES, M.Sc. (Lond.), F.G.S.
                  W. O. R. WYNN, A.I.C.

                              _Assistants_

                    S. BANN.
                    F. H. BELL.
                    H. BENNETT, B.Sc. (Lond.).
                    A. T. FAIRCLOTH.
                    R. C. GROVES, M.Sc. (Birm.).
                    E. HALSE, A.R.S.M., M.Inst.M.M.




                                PREFACE


The Mineral Resources Committee of the Imperial Institute has arranged
for the issue of this series of Monographs on Mineral Resources in
amplification and extension of those which have appeared in the
_Bulletin of the Imperial Institute_ during the past fifteen years.

The Monographs are prepared either by members of the Scientific and
Technical Staff of the Imperial Institute, or by external contributors,
to whom have been available the statistical and other special
information relating to mineral resources collected and arranged at the
Imperial Institute.

The object of these Monographs is to give a general account of the
occurrences and commercial utilisation of the more important minerals,
particularly in the British Empire. No attempt has been made to give
details of mining or metallurgical processes.

                                             HARCOURT,
                                 _Chairman Mineral Resources Committee_.

  IMPERIAL INSTITUTE, LONDON, S.W.7.
              _July 1920._




                                CONTENTS


                                CHAPTER I

                                                                    PAGE
 =THE PLATINUM METALS: THEIR OCCURRENCES, CHARACTERS AND USES.
   WORLD’S OUTPUT=                                                     1


                               CHAPTER II

                 =SOURCES OF SUPPLY OF PLATINUM METALS=

 (_a_) BRITISH EMPIRE:                                                 16
      _Europe_: United Kingdom.
      _Asia_: India (Burma).
      _Africa_: Rhodesia; Union of South Africa.
      _America_: Canada; Newfoundland.
      _Australasia_: Australia; New Zealand.


                               CHAPTER III

                 =SOURCES OF SUPPLY OF PLATINUM METALS=

 (_b_) FOREIGN COUNTRIES:                                              32
      _Europe_: France; Finland; Germany; Lapland; Russia; Spain.
      _Asia_: Armenia; Borneo; China; Japan; Sumatra.
      _Africa_: Congo Free State; Madagascar.
      _America_: Brazil; Colombia; Ecuador; Mexico; United States.

 WORLD MAP OF PLATINUM DEPOSITS                                       59

 REFERENCES TO LITERATURE ON THE PLATINUM GROUP                       60


 NOTE.—_Numerals in square brackets in the text refer to the Bibliography
                               at the end._




                          THE PLATINUM METALS




                               CHAPTER I
        PLATINUM METALS: THEIR OCCURRENCES, CHARACTERS AND USES


                              INTRODUCTION

The metals which comprise the Platinum group are the following:
Platinum, Palladium, Iridium, Osmium, Ruthenium and Rhodium.

Up to the year 1914 Russia produced over 90 per cent. of the world’s
supply of platinum, the Republic of Colombia, South America, ranking
next in importance with about 5 per cent. Owing, however, to the war and
to the chaotic conditions brought about by the revolution, the output of
Russia has considerably decreased, and although the Colombian production
has been steadily increasing, the increased demand in connection with
munition manufacture caused a somewhat serious shortage during the
latter stages of the war, which was especially felt in the United
States. As a result much exploratory work has recently been carried on
in an endeavour to discover new deposits of importance; but up to the
present, although several fresh occurrences have been brought to light,
results have on the whole been disappointing.


                              OCCURRENCES

Platinum usually occurs in nature as native metal alloyed with one or
more of its allied metals in the form of very fine grains more or less
flattened; sometimes in the form of irregular nuggets; and occasionally,
though rarely, in small cubic crystals. It is sometimes coated with a
black layer of iron oxide, which may be magnetic, in which case it is
not easily recognizable. When unrefined it is referred to as “crude”
platinum.

With the exception of a certain amount of the platinum metals, obtained
from the refining of copper and gold bullion, particularly from the
copper-nickel deposits of Sudbury, Ontario, about 99 per cent. of the
whole supply is derived from alluvial deposits. Several occurrences of
platinum _in situ_ are known, but so far few are of commercial
importance: however, in view of the indications of exhaustion shown by
some of the placer deposits, notably in Russia, the exploration of
primary ores is now receiving more attention and practical results have
already been achieved in Russia and in Spain.

The mother rocks from which the deposits are derived, in the large
majority of known cases, consist of basic and ultra-basic igneous rocks,
including peridotites, pyroxenites and dunites. The two first are
composed of iron magnesian silicates, pyroxene, augite and hornblende
with olivine, chromite, ilmenite and magnetite: the dunites consist
principally of olivine with some chromite. These rocks are often found
to have undergone more or less alteration to serpentine. In addition,
platinum has been found in quartz veins, notably at the Boss Mine,
Nevada, and in a few known cases it has been derived from formations in
schistose, or altered sedimentary rocks.

When present in serpentine, platinum is usually disseminated through the
rock in fine particles. It seldom occurs in a lode-formation. In
sedimentary rocks it usually occurs in sandstones. In cases where
alluvial deposits have been derived from the basic igneous rocks, the
associated minerals are usually chromite, magnetite, ilmenite, iridium
and osmiridium. In sedimentary deposits the metal is commonly associated
with quartz, copper, nickel, silver and palladium.

Platinum has been found in certain varieties of the copper ores
tetrahedrite and bournonite. It has occasionally been located in shales
and in coal, although not in recoverable quantities. In the latter case,
in an Australian coal, it is associated with vanadium[1] p. 992.

Several cases are known of platinum being present in meteorites, two
well-authenticated instances having been reported from Mexico. Platinum
has been shown to exist in meteoric iron from New South Wales.

Crude platinum, as recovered, contains from 70 to 90 per cent. of the
metal, and, as mentioned above, is really an alloy of platinum with one
or more of the allied metals, the chief impurities consisting
principally of iron and copper.

The table on the next page gives the analyses of typical samples of
crude platinum from the Urals, California, British Columbia, and other
places.

Platinum also occurs in combination with arsenic in the mineral
_Sperrylite_ (PtAs_{2}), in the form of minute octahedral crystals. The
colour of this mineral is tin white, its lustre is metallic and
brilliant, its hardness varies from 6 to 7, and its specific gravity is
10·6. The mineral is brittle and breaks with a conchoidal fracture. It
is very rare, and is interesting as being the only mineral of platinum
known besides the native metal. It occurs associated with sulphide
minerals of magmatic origin in gabbros and diabases, notably in the
nickeliferous pyrites of Sudbury, Canada, and in the copper ores of the
Rambler Mine, Laramie, Wyoming.

It is probable that the palladium, which is also found in these
deposits, is similarly present in the form of an arsenide, but such a
mineral has not yet been definitely proved to exist.

The following is an analysis of a sample of sperrylite: platinum, 54·47
per cent.; rhodium, 0·76 per cent.; palladium, trace; arsenic, 42·23 per
cent.; antimony, 0·54 per cent.[2] p. 69.


                   PROPERTIES OF THE PLATINUM METALS

_Platinum._—The colour is white with a greyish tinge. When pure it is
very malleable and ductile. Its coefficient of expansion is less than
that of all other metals. Platinum fuses at about 1750° C., but the
presence of impurities lowers the melting-point. Its specific gravity is
21·5, and its hardness is from 4 to 5. Its electric conductivity is low,
being 13·4 at 0° C.[3] p. 398.


                _Composition of Native Platinum and Osmiridium_

 ──────────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬──────┬──────────────────
 Locality. │ Pt. │ Fe. │ Pd. │ Rh. │ Ir. │ Os. │ Cu. │Os-Ir.│     Remarks.
 ──────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼──────┼──────────────────
 _Platinum_│ Per │ Per │ Per │ Per │ Per │ Per │ Per │ Per  │
           │cent.│cent.│cent.│cent.│cent.│cent.│cent.│cent. │
 Urals 1[B]│76·22│17·13│ 1·87│ 2·50│ tr. │     │ 0·36│  0·50│Magnetic grs.
 Urals 2   │73·58│12·98│ 0·30│ 1·15│ 2·35│ tr. │ 5·20│  2·30│Magnetic grs.
 Urals 3   │81·34│11·48│ 0·32│ 2·14│ 2·42│ tr. │ 1·13│  0·57│Non-magnetic.
 Urals 4   │78·94│11·04│ 0·28│ 0·86│ 4·97│     │ 0·70│  1·96│Non-magnetic.
 Urals 5   │86·50│ 8·32│ 1·10│ 1·15│     │ tr. │ 0·45│  1·40│Non-magnetic.
 Borneo    │82·60│10·67│ 0·30│     │ 0·66│     │ 0·13│  3·80│Gold, 0·20 per
           │     │     │     │     │     │     │     │      │  cent.
 Brazil    │72·62│ tr. │21·82│     │ 0·88│     │     │      │Sand, 0·42 per
           │     │     │     │     │     │     │     │      │  cent.
 Granite   │68·19│ 7·87│ 8·26│ 3·10│ 1·21│     │ 3·09│ 14·62│Gangue, 1·69;
   Cr.,    │     │     │     │     │     │     │     │      │  non-magnetic.
   B.C.    │     │     │     │     │     │     │     │      │
 Granite   │78·43│ 9·78│ 0·09│ 1·70│ 1·04│     │ 3·89│  3·77│Gangue, 1·27;
   Cr.,    │     │     │     │     │     │     │     │      │  magnetic.
   B.C.    │     │     │     │     │     │     │     │      │
 Chocó,    │86·20│ 7·80│ 0·50│ 1·40│ 0·85│     │ 0·60│  0·85│Sand, 0·95.
   Col.    │     │     │     │     │     │     │     │      │
 Chocó,    │84·30│ 5·31│ 1·06│ 3·45│ 1·46│ 1·03│ 0·74│      │Gold, 1·0; sand,
   Col.    │     │     │     │     │     │     │     │      │  0·61.
 California│85·50│ 6·75│ 0·60│ 1·00│ 1·05│     │ 1·40│  1·10│Gold, 0·8; sand,
           │     │     │     │     │     │     │     │      │  2·95.
 California│79·85│ 4·45│ 1·95│ 0·65│ 4·20│     │ 0·75│  4·95│Gold, 0·55; sand,
           │     │     │     │     │     │     │     │      │  2·69.
 Oregon    │51·45│ 4·30│ 0·15│ 0·65│ 0·40│     │ 2·15│ 37·30│Sand, 3; gold,
           │     │     │     │     │     │     │     │      │  0·85.
 Fifield,  │75·80│10·15│ tr. │ 1·30│ 1·30│     │ 0·41│  9·30│Gold, nil; sand,
   N.S.W.  │     │     │     │     │     │     │     │      │  1·12.
 “Austra-  │61·40│ 4·55│ 1·80│ 1·85│ 1·10│     │ 1·10│ 26·00│Gold, 1·2; sand,
   lia”    │     │     │     │     │     │     │     │      │  1·4.
 Currumbin,│26·12│27·17│     │     │     │     │ 2·51│ 40·02│Sand, 1·33.
   Q.      │     │     │     │     │     │     │     │      │
   _Osmi-  │     │     │     │     │     │     │     │      │
  ridium_  │     │     │     │     │     │     │     │      │
 Urals     │10·08│ tr. │ tr. │ 1·51│55·24│27·23│ tr. │      │Ru, 5·85
           │     │     │     │     │     │     │     │      │  (_Nevyanskite_).
 Urals     │ 0·14│ 0·63│     │ 1·65│43·94│48·85│ 0·11│      │Ru, 4·58
           │     │     │     │     │     │     │     │      │  (_Nevyanskite_).
 California│     │     │     │ 2·60│53·50│43·40│     │      │Ru, 0·50
           │     │     │     │     │     │     │     │      │  (_Nevyanskite_).
 “Austra-  │     │     │     │ 3·04│58·13│33·46│ 0·15│      │Ru, 5·22
   lia”    │     │     │     │     │     │     │     │      │  (_Nevyanskite_).
 Currumbin,│ 3·00│     │     │     │62·00│33·00│     │      │Sand, 2·00
   Q.      │     │     │     │     │     │     │     │      │  (_Nevyanskite_).
           │     │     │     │    /\     │     │     │      │
 Tasmania  │ 0·37│ 0·30│ 0·21│   33·80   │57·09│ tr. │      │Ru, 8·19; Au, ·04
           │     │     │     │           │     │     │      │  (_Siserskite_).
  _Platin- │     │     │     │     │     │     │     │      │
  iridium_ │     │     │     │     │     │     │     │      │
 Condado,  │55·44│ 4·14│ 1·49│ 6·86│27·79│ tr. │ 3·30│      │
   Brazil  │     │     │     │     │     │     │     │      │
  _Native  │     │     │     │     │     │     │     │      │
  Iridium_ │     │     │     │     │     │     │     │      │
 Urals     │19·64│     │ 0·89│     │76·80│     │ 1·78│      │
 ──────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴──────┴──────────────────
 Reference—Pt., platinum;  Fe., iron;  Pd., palladium;  Rh., rhodium;  Ir.,
 iridium;  Os., osmium; Cu., copper;  Os-Ir., osmiridium;  Ru., ruthenium.

Footnote B:

  Average percentage of Urals platinum is a little under 80.[4] p. 558.

Platinum is not acted upon by either nitric, sulphuric or hydrochloric
acid, but is soluble in aqua regia (1 part of nitric to 2 parts of
hydrochloric acid), or in other mixtures liberating chlorine, with the
formation of platinum tetrachloride (PtCl_{4}). It is not acted upon by
air or moisture, even at high temperatures. It is corroded by caustic
alkalis, sulphides, sulphates, phosphates and arsenides, if heated in
contact with them. It will not amalgamate with mercury unless sodium is
present, in this respect differing from gold and silver.

Platinum, in a finely-divided condition, absorbs large quantities of
hydrogen or other gases, which on occlusion become more active: hence
its value as a catalytic agent.

_Palladium._—This metal resembles platinum, but is sometimes fibrous,
the colour being between that of platinum and of silver. It possesses a
lower melting-point than platinum—about 1550° C. It is malleable, has a
hardness of from 4·5 to 5, and a specific gravity of 11·5. As already
stated, palladium, when found in copper ores, is probably present in
combination with arsenic. _Porpezite_, a rare mineral, containing gold
and up to 10 per cent. palladium, has been identified in gold-bearing
veins in Brazil [see p. 54].

Palladium is produced from the refining of copper matte and of base gold
bullion from Australia and elsewhere.

_Iridium_ is a brilliant white brittle metal, with a specific gravity of
22·4, and hardness of 6 to 7. Its fusion point is very high—about 2200°
C.—and under ordinary conditions it is not attacked by any acid. At
1100° C. it begins to oxidize to a purple oxide. Iridium usually occurs
either in crude platinum, or alloyed with osmium, as iridosmine, or as
native metal. The bulk of iridium is derived from the platinum placer
deposits of the Urals, but the Californian metal is more valuable, on
account of its better quality. It is also obtained in small amounts from
copper bullion.

_Osmium_ is a hard and brittle metal, bluish-grey in colour. Its
specific gravity is 22·5, and it has a very high melting-point, in this
respect being the most refractory of the group.

_Iridosmine_, or _Osmiridium_, an alloy of iridium and osmium, occurs as
hexagonal crystals, or flattened grains of lighter colour than platinum.
It may contain from 40 to 77 per cent. of iridium, and from 20 to 50 per
cent. of osmium. If the iridium predominates, the alloy is called
_Nevyanskite_, and _Siserskite_ if the osmium content is high. It is
distinguishable from platinum by the brittleness of the flakes.
Siserskite gives off a pungent odour, if strongly heated, caused by the
volatilization of osmium. Iridosmine has a hardness of 6 to 7, and a
specific gravity of 19 to 21.

_Ruthenium_ is a white metal, with a specific gravity of 12·1. It is
scarcely acted upon by aqua regia. Ruthenium occurs mainly in small
amounts in iridosmine. It is also found in the copper ores of Sudbury
and other places. _Laurite_ is a very rare sulphide of ruthenium
(RuS_{2}), containing a small amount of osmium, which has only been
recognized in the Borneo deposits.

_Rhodium_ is a white metal resembling aluminium, with a specific gravity
of 12·1, and a melting-point of about 2000° C. It is ductile and
malleable at red heat. In addition to its occurrence in crude platinum,
the metal is also contained in small quantities in the sperrylite found
in the copper ores of Sudbury, Canada[5] p. 779.

_Colloidal Platinum._—This has only recently been detected in ores, and
therefore its occurrence might not be detected qualitatively. By
destroying its colloidal condition, however, its presence can be
discovered in the ordinary ways[4].


                        METALLURGICAL TREATMENT

Crude platinum can be refined either by dry or by wet methods, the
following being brief outlines of the two processes:

By the wet method, the crude platinum is dissolved in aqua regia, with
excess of hydrochloric acid. Evaporation is continued until the whole of
the nitric acid is expelled. By addition of a solution of ammonium
chloride, the platinum is then precipitated as ammonium
platini-chloride. This precipitate is heated to redness, when chlorine
and ammonium chloride are given off, and spongy platinum remains. The
last is next granulated, after fusion by the oxy-hydrogen blowpipe in a
small lime furnace. Platinum obtained by this method may contain small
amounts of iridium, rhodium and palladium.

In the dry method, introduced by Delville and Debray, the crude platinum
is smelted with galena in a small reverberatory furnace. A portion of
the lead is reduced to the metallic state by the iron in the charge, and
forms a fusible alloy with the platinum. The osmiridium present settles
to the bottom of the furnace, and may thus be removed. Litharge is then
thrown in to form more alloy, and some glass to act as a flux. The alloy
is cupelled, and the residual platinum is then melted in a lime furnace
with the oxy-hydrogen flame. The platinum thus obtained often contains
iridium and rhodium.

A combination of these two methods is also sometimes employed[3] p. 403.

The electrolytic process of gold-refining was introduced to treat
platiniferous gold. In the gold chloride, or Wohlwill method, iridium
and osmiridium are insoluble, and remain with the anode slime. Platinum
and palladium, if nearly pure, are also insoluble, but when present
alloyed with gold and silver, pass into the solution and remain there.
In a hot bath it is stated that the platinum present should not exceed
50 gm. per litre. According to T. K. Rose, a cold bath containing only
20 gm. per litre causes a certain quantity of platinum to be deposited
with the gold[6].

H. F. Keller, in “Platinum, the Most Precious of Metals” (_Journal of
the Franklin Institute_, November 1912) deals fully with the extraction
and refining of platinum.


                       PLATINUM-REFINING AGENCIES

The following contains a list of the principal firms engaged in the
refining of platinum metals:


In England: Johnson, Matthey & Co., Ltd., Lees & Sanders, Warstone
Smelting Works, Sheffield Smelting Works, Johnson & Sons. (This is the
list of the Ministry of Munitions.)

In France: Legende et Cie., Compagnie Internationale du Platine, Lyon
Allemand, Lecht Lyonnais, Henrique Marrett, Bonnen, Hesse Fils.

In Germany: W. C. Heraeus, G. Siebert, F. Eisennad & Co.

In the United States: Baker & Co., American Platinum Works (N.T.),
Irvington Smelting and Refining Works, J. Bishop & Co., H. A. Wilson &
Co., Belais & Cohn, Kastenhuber & Lehrfeld, Roessler & Hasslacher
Chemical Co., Wildberg Bros., and others handling scrap.

According to Russian information about 25 per cent. of the Russian
output before the war was refined in Germany. In Russia there are
practically no platinum-refining facilities[7].


                  THE USES OF PLATINUM AND ITS ALLIES

_Platinum._—In the chemical industry platinum is largely used for
catalyzers in the manufacture of sulphuric, acetic and nitric acids; for
stills for the final concentration of sulphuric acid; and in the
electro-chemical industry.

In the making of “contact” sulphuric acid a “contact mass” is charged
into the chambers of the plant. This is formed by soaking asbestos, or
anhydrous magnesium sulphate, with platinic chloride solution, and
baking the mass to drive off the chlorine. The contact mass usually
contains from 7 to 8 per cent. platinum, in a very finely-divided state.
In the making of acetic acid from a mixture of air and alcohol vapour,
platinized asbestos is used. For the catalyzer used in the conversion of
ammonia into nitric acid a very fine-meshed platinum gauze is used; this
is strengthened at its edges with platinum-iridium wire. One ounce of
platinum is required for the production per annum of 25 tons of
catalytic acid, or of 40 tons of nitric acid from ammonia.

In the finely-divided state all the other metals of the platinum group,
especially palladium, have also the facility of absorbing great
quantities of certain gases, and can be used as catalysts.

Owing to its high melting-point, and to the resistance to the action of
acids at high temperatures, platinum is largely used for chemical ware
in the form of crucibles, dishes, etc. Platinum crucibles are
indispensable in the chemical analysis of rocks.

In the electrical industry platinum is largely used for contact points,
in telegraph and telephone apparatus, in magneto-contacts, and in the
construction of the thermo-couples of pyrometers. In the manufacture of
jewellery, especially in the crown-setting of diamonds, platinum has
been much used in the place of gold: alloyed with a little iridium it
can be worked into delicate designs, which are durable. During the war,
however, when platinum was largely wanted in the making of munitions,
its use in jewellery manufacture was much restricted. Platinum was
formerly largely used in dentistry. In photography potassium
platino-chloride is required for producing platinotype prints. In the
form of barium platino-cyanide it is used in X-ray photography as a
coating for the projecting screen.

Platinum is required in the manufacture of certain parts of
chronometers, theodolites and watches; also for standard weights and
measures, and for various types of self-lighting lamps[4] p. 561.

_Palladium_ has its chief value as a substitute for platinum, in
palladium-gold alloys, which are used extensively in dentistry, for
jewellery and for chemical ware. It is also utilized in the manufacture
of astronomical instruments and watches, also for plating metal ware[1]
p. 1002. The use of palladium as a catalyzer is well known.

_Iridium_, when pure, is of small value, being difficult to manipulate
on account of its brittleness. It is principally used in alloy with
platinum for hardening purposes. Jewellers’ platinum usually contains 10
per cent. iridium, and in the electrical industry an alloy composed of
from 15 to 50 per cent. iridium is usually employed. Alloys with up to
10 per cent. of iridium are ductile and malleable, but with over that
amount are hard and difficult to work.

The metal is used in the manufacture of fountain-pen points, for which
purpose the grains require careful selecting[8] p. 106; also for
standard weights and for contact points. Iridium black, an oxide, is of
value as a pigment for chinaware[1] p. 1001.

Iridium is suitable for sharp surgical instruments, and gold needles
with soldered iridium ends are employed for stitching wounds. It is also
used in photography. Iridium is of greater scarcity than platinum, hence
its greater value.

_Osmium._—There is now little or no market for osmium. It was formerly
in considerable use for the manufacture of incandescent lamps. Osmic
acid is used for staining anatomical preparations in microscopic work.
On account of the poisonous nature of its vapour the extraction of
osmium is costly and dangerous.

_Ruthenium_ is also of little or no commercial value. Both these metals
possess the disadvantages of being brittle and easily oxidized.

_Rhodium_ is of small commercial use. It is used principally in alloy
with platinum. An alloy containing 10 per cent. rhodium is used for some
thermo-couples of pyrometers, and in the making of laboratory utensils.

_Platinum Alloys._—Platinum forms alloys with a number of metals, but
only a few are of industrial importance[3] p. 400. Platinum and iridium
form a hard and elastic alloy, which is unaffected by air, and takes a
high polish. Alloyed with 10 per cent. iridium platinum is used for one
of the wires in thermo-couples of pyrometers; and with 10 to 20 per
cent. iridium for making standard measures of length and weight.

Platinum and copper form various alloys. An alloy with 18·75 per cent.
copper, called “coopers’ gold,” takes a high polish and closely
resembles 18–carat gold.

An alloy of platinum and silver containing 66 per cent. silver is used
as a standard of electrical resistance. An alloy containing 20 to 30 per
cent. silver is used in dentistry.

Platinum alloys with lead, zinc and other metals at low temperatures; it
is usually recovered from these alloys by cupellation.

Platinum alloys with steel in all proportions. With 10 per cent.
platinum, rusting is prevented. A very elastic metal is produced by
alloying platinum with from 5 to 10 per cent. gold.

The melting-point of silver is raised by alloying it with platinum, but
its thermal conductivity is lowered.


   The following table gives the composition of the principal platinum and
                         palladium alloys[4] p. 561:

 ───────────────────┬──────┬──────┬──────┬──────┬──────┬──────┬─────────────
                    │ Pt.  │ Cu.  │ Ag.  │ Au.  │ Ni.  │ Pd.  │    Other
                    │      │      │      │      │      │      │Constituents.
 ───────────────────┼──────┼──────┼──────┼──────┼──────┼──────┼─────────────
                    │Parts.│Parts.│Parts.│Parts.│Parts.│Parts.│   Parts.
 Jewellery alloys:  │      │      │      │      │      │      │
   Platinum alloy   │     1│   0–1│   2–5│      │      │      │
   Platinor         │     2│     5│     1│      │     1│      │Brass 2.
   Palladium alloy  │      │      │      │      │      │     9│Rhodium 1.
   Mock gold        │     7│    16│      │      │      │      │Zinc 1.
   Mock gold        │     1│      │     1│      │     6│      │Brass 1.
   Mock gold        │     1│     4│      │      │      │      │
 Coopers’ pen metal:│     4│     1│     3│      │      │      │
   Watch alloy      │      │    13│    11│    18│      │     6│
   Watch alloy      │      │    25│     4│      │     1│    70│
   Watch alloy      │    63│    18│      │      │    17│      │Cadmium 1.
 Platinum bronze    │     1│      │      │      │    90│      │Tin 9.
   Dentists’ alloy  │     5│      │      │     3│      │     4│
   Dentists’ alloy  │     7│      │     3│     2│      │      │
   Dentists’ alloy  │     6│      │     1│     2│      │      │
   Dentists’ alloy  │      │      │      │     4│      │     1│
 Palladium alloy    │      │      │     2│      │      │     3│
 ───────────────────┴──────┴──────┴──────┴──────┴──────┴──────┴─────────────


                     ALLOY SUBSTITUTES FOR PLATINUM

On account of the scarcity and high price of the platinum metals, much
attention has lately been directed towards the discovery of suitable
substitutes.

In the electrical industry an alloy of 3 parts of palladium and 2 parts
of silver is in use, also an alloy of nickel and chromium. _Platinite_,
an iron-nickel alloy, containing 46 per cent. nickel and 0·15 per cent.
carbon, has the same coefficient of expansion as glass, and, when coated
with copper, is used to replace the platinum connection wires of
incandescent lamps. Tungsten is sometimes used for certain ignition
devices. For cathodes an alloy of 90 per cent. gold and 10 per cent.
copper can be used to replace platinum; the same alloy, if electrically
coated with platinum, and then carefully polished and burnished, is
suitable for platinum anodes.

For platinum chemical laboratory ware, there are several substitutes,
such as fused quartz; various iron, chromium, and nickel-chromium
alloys; _palau_, a gold-iridium alloy marketed in California;
_rhotanum_, a general name for gold-palladium alloys containing from 60
to 90 per cent. of gold, which are suitable for most chemical purposes,
except for use with hot concentrated nitric acid, and for electrolytic
anodes; _amaloy_, which is a complex alloy containing nickel, chromium,
tungsten, etc., highly resistant to corrosion and to cold nitric and
sulphuric acids[9] p. 600.

In the jewellery trade platinum has been replaced by an alloy of 90 per
cent. palladium and 10 per cent. rhodium. For certain surgical work
various _stellite_ alloys, containing cobalt and chromium, and hardened
by the addition of tungsten and molybdenum, are valuable substitutes for
platinum, and are not affected by antiseptic solutions. In dental work
pins are now made of tungsten coated with palladium[10] p. 549. For most
technical purposes an alloy of tungsten and nickel with gold or silver
is used in Germany; it may be cast, rolled or forged, is acid-resisting,
and capable of taking a high polish[11]. _White gold_, another
substitute for platinum, contains fine gold, from 75 to 85 per cent.;
pure nickel, from 10 to 18 per cent.; and zinc, from 2 to 9 per cent.
_Illium_, a chromium-nickel-copper alloy reported recently as the
discovery of S. W. Parr, of Illinois, is a substitute for gold or
platinum, costing only 25 cents per ounce. It is stated to have been a
“50 per cent. standard of success.” The alloy withstands hot or cold,
strong or diluted acid, can be both cast and machined, and is already
used largely in the manufacture of calorimeter bombs[12].

The results of researches made to discover substitutes for platinum, and
undertaken by the National Dental Association of America, are described
at length by F. A. Fahrenwald, in a paper read in January 1916 before
the American Institute of Mining Engineers.


                             SCRAP PLATINUM

A considerable amount of platinum in the form of old and worn articles
is now collected for return to the refineries, where it is re-treated,
and sold again as new metal. The trade in scrap platinum has been
particularly active in the United States, official statistics showing
that in 1916, 49,400 oz. of refined platinum were recovered.


                       WORLD’S OUTPUT OF PLATINUM

According to J. L. Howe, the estimated limits of the total
world-production of crude platinum, up to January 1917, were as
follows[13]:


                                 _In oz._   (_troy_)
                                 Minimum.   Maximum.
                   Russia        7,115,482 10,128,308
                   Colombia        700,000    735,000
                   Borneo          175,000    200,000
                   United States    10,000     12,000
                   Canada            9,000     10,000
                   Miscellaneous     9,000     10,000
                                 ————————— ——————————
                       Total     8,018,482 11,095,308
                                 ========= ==========

On the other hand, James M. Hill[14] states that possibly 5,000,000 oz.
was the total world’s production to June 1917, which he distributes
according to the uses made of it as follows:


                                                   Oz.
               Chemical and physical apparatus  1,000,000
               Electrical devices                 250,000
               Catalyzing                         500,000
               Dental uses                      1,000,000
               Jewellery                        1,000,000
               Minor uses and hoarded (balance) 1,250,000

It is difficult to obtain exact figures of the annual production of
crude platinum. This is particularly so in the case of Russia, where
there appears to have been a tendency for private enterprises to keep
their published outputs as low as possible, in order to avoid
registration. The discrepancy between the official and actual figures of
production in Russia is variously estimated at from 20 to 60 per cent.

The table on the next page is compiled from the sources considered most
reliable.


                 _World’s Production of Crude Platinum_

                             (In troy oz.)

 ─────────────────────┬───────┬───────┬───────┬───────┬───────
                      │ 1910. │ 1911. │ 1912. │ 1913. │ 1914.
 ─────────────────────┼───────┼───────┼───────┼───────┼───────
 Borneo and Sumatra[C]│       │       │    200│    200│    [D]
 Burma[E]             │       │     38│     57│     58│     37
 Canada[F]            │       │       │       │       │     18
 Colombia[G]          │ 10,000│ 12,000│ 12,000│ 15,000│ 17,500
 Madagascar[H]        │     13│      3│       │       │
 New South Wales[I]   │    332│    470│    610│    442│    244
 Russia[J]            │176,334│187,008│177,596│157,735│157,182
 United States[C]     │    390│    628│    721│    483│    570
 Victoria[L]          │       │    184│       │    127│
 ─────────────────────┴───────┴───────┴───────┴───────┴───────

 ─────────────────────┬───────┬───────┬─────────┬──────
                      │ 1915. │ 1916. │  1917.  │1918.
 ─────────────────────┼───────┼───────┼─────────┼──────
 Borneo and Sumatra[C]│    [D]│    [D]│      [D]│
 Burma[E]             │     18│      9│        4│
 Canada[F]            │     23│     15│       57│    39
 Colombia[G]          │ 18,000│ 25,000│   32,000│27,030
 Madagascar[H]        │       │       │         │
 New South Wales[I]   │     56│     82│      259│
 Russia[J]            │119,789│ 78,682│50,000[K]│
 United States[C]     │    742│    750│      605│
 Victoria[L]          │       │       │         │
 ─────────────────────┴───────┴───────┴─────────┴──────

  _Canada._—The recoveries of platinum at the works of the
  International Nickel Company in New Jersey for the years 1910–1912
  were 258,666 and 497 oz. respectively, chiefly from Canadian matte.

  _Russia._—The _actual_ productions of platinum as quoted in _Mineral
  Industry_ in oz. were: 1910, 300,000; 1911, 280,000; 1912, 300,000;
  1913, 275,000; 1914, 240,000; 1915, 124,000; 1916, 90,000; 1917,
  50,000.

Footnote C:

  _U.S.A. Mineral Resources, 1917, Geol. Surv._

Footnote D:

  Estimates not available.

Footnote E:

  _Records of Geol. Survey, India._

Footnote F:

  _Mineral Production_, Mines Dept., Canada. Figures are for alluvial
  production only, and far below _actual_ production figures, not
  including Ontario production from nickel matte, for which only
  incomplete information is available. [See p. 25.]

Footnote G:

  _Mining Journal_, November 30, 1918, p. 700, and _Mineral Industry_.

Footnote H:

  _Mines and Quarries Reports_, Home Office.

Footnote I:

  _Annual Rept. Dept. of Mines._

Footnote J:

  _Mineral Industry._ These are _official_ figures for production;
  _actual_ production is much greater than these.

Footnote K:

  Estimated.

Footnote L:

  _Dept. of Mines Reports_ (platinum obtained from copper matte).

The market value of platinum has risen considerably since 1880. In that
year the price was 12_s._ 7½_d._ per oz. troy, in 1890 it was 25_s._
3_d._, and in 1900, 63_s._ 1½_d._ The average prices in London and New
York for the years 1910–1919 were as shown on the accompanying tables:


 Average price in pounds per troy oz. of refined metals of the platinum
                             group in London

 ─────────┬─────┬─────┬─────┬─────┬─────┬─────┬───────┬─────┬─────┬─────
          │1910.│1911.│1912.│1913.│1914.│1915.│ 1916. │1917.│1918.│1919.
 ─────────┼─────┼─────┼─────┼─────┼─────┼─────┼───────┼─────┼─────┼─────
 Platinum │  9·1│  8·6│  9·5│  9·5│  8·1│ 10·9│10–14·5│ 14·5│   20│   24
   Metals │     │     │     │     │     │     │       │     │     │
 ─────────┴─────┴─────┴─────┴─────┴─────┴─────┴───────┴─────┴─────┴─────

  1910, 1915, 1916 and 1917—_Metal Market Year Book_. 1911, 1912, 1913
  and 1914—_Mining Magazine_.


 Average price in dollars per troy oz. of refined metals of the platinum
                            group in New York

 ──────────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬─────┬──────┬─────
           │1910.│1911.│1912.│1913.│1914.│1915.│1916.│1917.│1918. │1919.
 ──────────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼─────┼──────┼─────
 Platinum  │   33│   43│   46│   45│   45│   50│   84│  103│106[M]│  114
 Iridium   │     │     │     │     │   65│   83│   94│  150│      │
 Iridosmine│     │     │     │     │   33│   35│   45│   80│      │
 Palladium │     │     │     │     │   44│   56│   67│  110│      │
 ──────────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴─────┴──────┴─────

  1910, 1914, 1915, 1916 and 1917—_U.S. Geol. Surv. Mineral
  Resources_.

  1911, 1912, 1913, 1918 and 1919—_Eng. and Min. Journ._, vol. 107,
  No. 2, p. 77.

Footnote M:

  The price was fixed on May 14, 1918, at $105.




                               CHAPTER II
            SOURCES OF SUPPLY OF PLATINUM AND ALLIED METALS

                          (_a_) BRITISH EMPIRE

The outputs of platinum metals in different parts of the British Empire
are shown in the table on p. 14.


                                 EUROPE


                             UNITED KINGDOM

There is no known occurrence of platinum in the United Kingdom, but
there has always been much trade done there in the platinum metals,
England having been the second largest importer of the big consuming
nations. The following were the importations of Russian platinum for
five periods since 1863:


                           _Period_   _Oz._
                           1863–1880 512,005
                           1881–1890 167,999
                           1891–1900 437,645
                           1901–1910 259,111
                           1911–1915  71,624

                              [15] p. 923

The above figures do not include receipts of platinum for seven
different years since 1863, for which there are no records.

The table on the next page gives a summary of total imports of platinum
metals for the years 1910–1918, with the countries of origin.

The platinum market in London was controlled by the Government from
January 1916 to December 1918, Johnson, Matthey & Co., Ltd., acting as
buyers. On December 26, 1916, platinum was declared contraband.


 _Imports of Platinum Metals, wrought and unwrought, into United Kingdom_
                             (_in troy oz._)

 ───────────────────────────┬──────┬──────┬──────┬──────
                            │1910. │1911. │1912. │1913.
 ───────────────────────────┼──────┼──────┼──────┼──────
 _From British countries_   │    24│ 1,011│ 1,100│
 _From foreign countries_:  │      │      │      │
     Russia                 │ 4,167│ 2,579│   461│ 1,778
     Germany                │ 5,837│ 8,786│ 1,669│    50
     France                 │35,149│30,449│33,969│33,149
     United States          │   494│   794│   644│ 3,623
     Colombia               │ 2,037│ 4,909│ 4,552│ 3,725
     Other foreign countries│   454│      │   158│   315
 ───────────────────────────┼──────┼──────┼──────┼──────
 Total: foreign countries   │48,138│47,517│41,453│42,640
 ───────────────────────────┼──────┼──────┼──────┼──────
 Grand total, oz.           │48,162│48,528│42,553│42,640
 ───────────────────────────┴──────┴──────┴──────┴──────

 ───────────────────────────┬──────┬─────┬─────┬─────┬─────
                            │1914. │1915.│1916.│1917.│1918.
 ───────────────────────────┼──────┼─────┼─────┼─────┼─────
 _From British countries_   │      │     │   28│  458│  265
 _From foreign countries_:  │      │     │     │     │
     Russia                 │      │    7│     │     │
     Germany                │     3│     │     │     │
     France                 │12,592│1,878│1,666│  632│  596
     United States          │   257│1,265│  191│2,716│
     Colombia               │ 2,296│  139│     │     │
     Other foreign countries│    40│   59│   79│     │  362
 ───────────────────────────┼──────┼─────┼─────┼─────┼─────
 Total: foreign countries   │15,188│3,348│1,936│3,348│  958
 ───────────────────────────┼──────┼─────┼─────┼─────┼─────
 Grand total, oz.           │15,188│3,348│1,964│3,806│1,223
 ───────────────────────────┴──────┴─────┴─────┴─────┴─────

                                  [16]

About 7 per cent. of the Russian and one-half of the Colombian outputs
were sold to England during the war, as well as most of the Australian
and Indian production. Much of this metal was refined in the United
States.

According to J. E. Orchard[17], the commercial control (financial) of
the world’s output of platinum of 267,233 oz. of 1913 was divided as
follows: France, 74 per cent.; Russia, 18 per cent.; United States, 4
per cent.; British Empire, 2 per cent.; other countries, 2 per cent.;
whilst the political control (territorial) was divided as follows:
Russia, 93 per cent.; Colombia, 6 per cent.; other countries, 1 per
cent.


                                  ASIA


                                 INDIA

Traces of platinum and iridium have been noticed in association with the
gold obtained from native workings at Bonai City. The gold occurs in a
deposit of iron oxide, which forms the cementing material in a hard
stratum of quartz pebbles. The oxide is separated by pounding, and then
washed away to extract the gold. The proportion of platinum to gold is
probably less than 1 to 20.

Platinum occurs, associated with gold, in the gravels of the Irawaddy
River in Burma. A small quantity of platinum is obtained at Myitkyina by
the Burma Gold Dredging Company. During the years 1911–13, 152 oz. were
won by this company. In 1915 the output was 17·7 oz., and in 1916, 9·25
oz. In 1917, 4 oz. only were produced[18]. Owing to the cessation of the
golddredging operations at Myitkyina, Burma has ceased to produce
platinum, the quantity recovered during the year 1918 being only 0·31
oz.[19].

It has also been located with iridosmine in the auriferous gravels of
the rivers draining the slopes of the Patkoi Ranges, both on the Assam
and Burma sides[20].


                                 AFRICA


                                RHODESIA

Platinum has recently been located in the Gwelo district, about 6 miles
north-east of Indiva siding, where it occurs in the great dyke of
norite, which is here about 4 miles wide. A. E. V. Zealley, the late
assistant Government geologist, made this occurrence the subject of a
special report[21].

The country rock is a serpentinized dunite. The deposit is capped by a
ferruginous siliceous gossan from 4 to 5 ft. wide, which may be traced
on the surface for about 100 ft., and is comparable to a fissure vein.
The gossan consists largely of hæmatite and chalcedony, with occasional
veinlets of copper and nickel minerals. Although the presence of
platinum in the ore could not be detected by panning, the possibility of
its occurrence on geological grounds was considered, and a sample of
concentrate from an unstated amount of ore was forwarded to the Imperial
Institute for analysis. The sample was found to contain platinum to the
amount of 1 dwt. 20 gr. per ton. A report on the further development of
this deposit is awaited with interest.

A sample of concentrate from an unstated amount of material from the
gem-bearing gravels of Somabula Forest, Gwelo district, was received at
the Imperial Institute from the Director of the Geological Survey of
Southern Rhodesia in November, 1918. On analysis this sample yielded the
following per ton: platinum, 3 oz. 12 dwt.; osmiridium, 7 oz. The
concentrate also contained a large proportion of gold. As shown by the
latest information available, the deposits, although undoubtedly rich,
appear to extend over a limited area. According to an analysis made at
the Imperial Institute, a sample of chromite from Southern Rhodesia
(Selukwe) contained 0·17 per cent. copper and nickel oxides, and a trace
of platinum[22].

H. B. Maufe[23] has stated that as the River Umtebekwe drains two areas
of ultra-basic rock containing chromite, it might be expected to contain
alluvial platinum, as well as gold, and, as a matter of fact, platinum
has actually been discovered in a reef in the Great Dyke (norite), at
the head of the Umtebekwe valley.

The presence of platinum was recently reported at Willoughby’s Halt, 12
miles south of Gwelo.


                         UNION OF SOUTH AFRICA

_Cape Colony_[24].—Platinum is present in varying quantities in the
copper-nickel deposits at Insizwa, situated in the Cape Province, close
to the boundary between East Griqualand and Pondoland.

The rock formation consists of a basin-shaped mass of intrusive norite,
averaging from 2,000 to 3,000 ft. in thickness, and lying in the shales
and sandstones of the Beaufort Series of the Karroo System.

The ore body consists of sulphides of copper and nickel, in association
with pyrrhotite, the minerals occurring disseminated near the basal
margin of the intrusive in olivine picrite. Gold and silver are also
present in small quantities.

The average copper and nickel contents in the ore are each about 4 per
cent., and the platinum content averages from 2 to 3 dwt. per ton, the
platinum being unequally distributed through the ore[25] p. 14.

It is not certain in what form the platinum occurs. It does not appear
to be present as sperrylite. In the opinion of W. H. Goodchild it may
occur in close association with the silver[25] p. 35.

Mining operations have been intermittently carried on here during the
last fifty years, the last exploratory work coming to an end in 1911.
Operations were, however, resumed early in 1920.

_Transvaal._—Small amounts of platinum and its allied metals have from
time to time been noticed in black sands from the battery “clean-ups” on
the Rand at Klerksdorp and other gold-mining districts, and platinum to
the amount of 2½ dwt. per ton is reported to have been present in
residual slimes at the Rietfontein mines[26]. A specimen, consisting of
about 85 per cent. osmiridium and 15 per cent. platinum, recently
received at the Imperial Institute, was stated to have been taken from a
compact shale, immediately underlying the banket reef in one of the
mines of the Klerksdorp district. In the large majority of the gold
mines, however, the platinum metals, if present, appear to exist in such
small quantities as to escape detection.

A series of samples of chromite from Kromdaal, near Rustenburg, showed
from a mere trace to 1 dwt. of platinum per ton, and one sample of
chromite from the Secocoeniland deposits showed as much as 1½ dwt. of
platinum per ton[27].


                             NORTH AMERICA


                                 CANADA

The occurrence of platinum in Canada was first observed in 1862, in the
course of gold-mining operations on the Rivière-du-Loup and the
Rivière-des-Plantes in the province of Quebec[28] p. 210.

Since that time platinum has been found in a number of localities
associated with auriferous gravels, but the crude metal has only been
obtained commercially from the Similkameen district in British Columbia.
These deposits first attracted attention in 1885. All the workings are
alluvial, although the platinum has in several cases been traced to its
parent source.

_Alberta._—Platinum and gold in minute grains, closely intermixed, are
found in the North Saskatchewan River, near Edmonton. In 1918 certain
platinum occurrences were examined by the Munitions Resources
Commission, visits being paid to Fort Saskatchewan and the Peace River
district, in Alberta. These deposits, however, proved to be
disappointing. In the former locality, which was carefully tested by
drilling, the values of the samples obtained averaged less than 10 cents
in gold and platinum per c. yd. of gravel[29] p. 427.

_British Columbia._—Platinum, associated with gold, which is the
dominant metal, occurs in the Tulameen River and its tributaries, the
principal of which is Slate Creek, others being Cedar, Eagle, Bear and
Granite Creeks. The metal is present in small rounded grains, or
pellets. Chromite is often found intergrown with the platinum, olivine
and pyroxene usually occurring in association. The heavy minerals
remaining with platinum in the concentrate are titaniferous magnetite,
chromite and native copper. The platinum is sometimes magnetic, probably
due to the covering of the grains by small particles of magnetite[30].

The following analysis, according to G. C. Hoffmann, is representative
of an average sample of crude platinum from the Tulameen River:


                                        Per cent.
                      Platinum              72·07
                      Palladium              0·19
                      Rhodium                2·57
                      Iridium                1·14
                      Osmiridium            10·51
                      Copper                 3·39
                      Iron                   8·59
                      Gangue (Chromite)      1·69

Owing to the presence of osmiridium in considerable proportion, the ore
is classed as “hard metal,” and on that account fetches a higher price.
Many of the richer placers have become exhausted, and work is now
carried on by a few individuals, principally Chinese, who work during
the summer months only. In some cases high benches, 50 to 100 ft. above
the creek bottom, are being worked. Much of the platinum and gold is of
a coarse texture, with a rough surface, and the latter is sometimes
found embedded in quartz. Nuggets are sometimes found encrusted with
chromite, and are thus liable to be overlooked. The deposits are
therefore not of great age, and the metals have not been transported
long distances from their sources.

Kemp is of opinion that the platinum is derived from pyroxenite dykes
cutting through peridotites, which outcrop on Olivine and Grasshopper
Mountains.

It is of interest to note that some diamonds and rubies have been
discovered with the platinum in the Tulameen deposits. They are of good
quality, but of small size, and occur in a matrix of dunite[28] p. 210.
American capital dominates the platinum industry in the district. In
1918, at the request of the Imperial Munitions Board, special
investigations in this area were undertaken by members of the Geological
Survey, and several prospecting bores were put down to bedrock. Full
reports of the work done are not yet available, but it is understood
that the results are considered to be promising, and to warrant further
examination of the district[29] p. 429.

Platinum was in 1918 discovered at Franklin Camp, near Grand Forks,
B.C., in the “Black Lead,” so-called, which is a mixture of augite,
75·13 per cent.; orthoclase and microcline, 17·06 per cent.; hornblende,
1·47 per cent.; and magnetite, 6·06 per cent., as determined by
microscopic measurements on a typical specimen, with accessory minerals,
chalcopyrite, bornite and apatite. A sample of chalcopyrite assayed 0·38
oz. crude platinum per ton. Samples of the “Black Lead” assayed from
0·02 to 0·17 oz. per ton[31].

At Burnt Basin, on the Mother Lode claim, an auriferous quartz vein
carries platinum, in amounts varying from a trace to 0·25 oz. per ton.
The quartz also contains chalcopyrite, pyrite, galena, sphalerite and
molybdenite[31]. Native platinum in small quantities has been found
associated with gold in the following localities: Tranquille River,
Fraser River, Rock Creek, Yale District, North Thompson and Clearwater
Rivers. It has also been reported to occur in a dyke across the Kootenay
River upon the Granite Poorman Mining Company’s property a few miles
from Nelson[32]. At Siwash Creek, in the Tulameen district, small flakes
of platinum, associated with chromite, often occur in shear zones in
granite. Dredging for gold and platinum is being carried on, on the
Peace River, North British Columbia.

According to J. B. Hobson the heavy concentrate produced on the
Consolidated Caribo hydraulic mine at Quesnel, contains, besides gold
and silver, platinum, palladium and osmiridium, one analysis giving a
total value of $3,873 per ton. The gold and silver being non-amalgamable
are probably included in particles of pyrite and galena, whilst the
platinum metals are found as minute grains or are enclosed in particles
of chromite and magnetite. A system of “under-currents” is being
installed to properly dress this concentrate[33].

In 1917 the recorded output of crude platinum from the placer gravels of
the Tulameen district in British Columbia was 57 oz., that for 1918
being 39 oz. For the five years preceding 1892, this district produced
on an average over 1,500 oz. per year.

_Manitoba._—Samples of gold ore containing platinum have been obtained
in the Star Lake district of south-eastern Manitoba[34]. Analyses of the
samples from different auriferous reefs were made by the Department of
Mines in 1917, and yielded platinum varying in amount from a trace to
0·1 oz. per ton. In addition to gold and platinum, the veins carry small
quantities of galena, zinc blende, pyrite, chalcopyrite and arsenopyrite
in a gangue consisting mainly of quartz.

Platinum is reported to occur in auriferous quartz veins in several
mines and prospects in Le Pas district; a picked sample of ore from the
mine of the Northern Manitoba and Development Company, assayed $49 gold
and $17 platinum per ton[35]. McCafferty’s Prospect, about 5 miles away,
contains platiniferous quartz.

_Nova Scotia._—According to E. R. Faribault in _Summary Report_, 1918,
Part F, of the Canadian Department of Mines, platinum has been found,
mostly in traces, in some of the old gold districts of Halifax county
and, lately, in the tungsten concentrates of the Moose River mines. So
far, all occurrences are in quartz veins in the lower quartzite and
slate formation of the gold-bearing series of the Atlantic coast. The
platiniferous mineral is supposed to be sperrylite, with which is
associated arsenopyrite.

_Ontario._—Sudbury is one of the few places where platinum is profitably
extracted from deposits _in situ_. The metal, which was first discovered
in this region in 1889, is found mostly in combination with arsenic, as
sperrylite associated mainly with chalcopyrite in the well-known copper
and nickel-bearing deposits of the district.

The origin of the ore bodies has not yet been settled. They are either
marginal deposits in, or off-shoot deposits to, a norite laceolith,
which has intruded sedimentary rocks, the ores consisting principally of
chalcopyrite, pyrrhotite, and pentlandite. Metallic platinum, gold,
silver and palladium occur in the ore, the last also, probably, as an
arsenide. The highest platinum content is associated with the highest
copper content; the highest palladium with the highest nickel. According
to Roberts and Longyear[36] the mean analysis of rocks of from sixteen
drill holes gave an average ore content of: copper, 1·11 per cent.;
nickel, 1·95 per cent.; silver, 0·223 oz.; gold, 0·022 oz.; and metallic
platinum, 0·0068 oz. per ton. The ore is principally worked for its
nickel and copper content, and yields a large proportion of the world’s
supply of nickel. The ore is first smelted at the mines, and a portion
of the low-grade matte so produced is then shipped to South Wales for
final treatment, the remainder being sent to the recently-constructed
refinery of the International Nickel Co., at Port Colborne, Ontario, and
to the United States. It was stated in 1903 that this matte contained on
the average 1·25 oz. of the platinum metals per ton of nickel content of
the matte, of which about 80 per cent. was extracted[37] p. 10. The
Victoria Mine, owned by the Mond Nickel Co., is stated to carry a high
percentage of the precious metals, as is also the Vermilion Mine,
although in the latter case the ore body is very small. In 1917 the
total output of copper-nickel ore from these deposits amounted to
1,506,828 tons, of which the Canadian Copper Co. raised 1,139,629 tons,
the Mond Nickel Co. 361,335 tons, and the Alexo Mining Co. 5,864 tons.
The nickel content of the ore of the Canadian Copper Co. was about 2·5
times that of the copper, whilst the ore mined by the other two
companies contained the two metals in approximately equal proportions.
The matte produced by the Alexo Mining Co. is smelted by the Mond Nickel
Co. According to the report of the Royal Ontario Nickel Commission, the
matte produced by the Canadian Copper Co. in 1916 was estimated to
contain 4,640 oz. platinum and 8,460 oz. palladium, corresponding to
0·10 oz. platinum and 0·15 oz. palladium per ton of matte, the
International Nickel Co. recovering in that year 1,093 oz. platinum and
257 oz. allied metals. This company is now reported to have improved its
methods of recovery. In 1918 the total matte shipment by the Canadian
Copper Co. is stated to have contained, among other precious metals,
8,677 oz. platinum and 13,016 oz. palladium[38].

According to information supplied by the Mond Nickel Co., their nickel
residues derived from the refining of the matte are taken over by
Johnson, Matthey & Co., Ltd. During the years 1915–18 the residues
disposed of were estimated to contain the following amounts of platinum
metals:


                            (In oz. troy.)
              ───────────────────┬─────┬─────┬─────┬─────
                                 │1915.│1916.│1917.│1918.
              ───────────────────┼─────┼─────┼─────┼─────
              Platinum           │3,078│3,782│4,913│4,465
              Palladium          │5,474│     │     │
              Iridium and Rhodium│  973│     │     │
              ───────────────────┴─────┴─────┴─────┴─────


Messrs. Johnson, Matthey & Co., Ltd., have kindly supplied the following
figures of platinum-extraction from these residues:


                                  Oz. troy.
                             1916     3,722
                             1917     4,719
                             1918     4,958

The British America Nickel Corporation, who are developing some large
deposits in the same district, are also erecting a refinery near Hull on
the Ottawa River. It is stated that they will employ the Hybinette
process of electrolytic refining, and expect to obtain a high recovery
of the precious metals[29] p. 425.

With gradual improvements in the refining process, and with the refining
of the whole of the matte produced, instead of a portion only, as at
present, it seems probable that the production of platinum metals by the
three nickel companies may in time exceed 10,000 oz. per annum.

The 1919 report of the Ontario Bureau of Mines shows that in 1918 the
International Nickel Co. treated 62,250 tons of matte for 650 fine oz.
of platinum, 787 oz. of palladium, and 473 oz. of metals of the rhodium
group. This cannot be used as a basis of calculation, as the proportions
are not constant.

On the Quinn claims, near the Crœsus Mine, Munro Township, is auriferous
quartz containing platinum. Five assays gave a platinum content of value
ranging from $180 to $1,800 per ton (with platinum at from $40 to $50
per oz.)[31]. The Abro Mine in the Timiskaming district in 1915 shipped
between 5,000 and 6,000 tons of ore, containing 0·03 oz. of palladium
and platinum per ton. The ore consists of pyrrhotite, chalcopyrite and
pentlandite, in a gangue of altered peridotite and serpentine[7].

_Yukon Territory._—Platinum occurs associated with gold in small
quantities in most of the tributaries of the Yukon River, notably at the
mouth of the Hootalinqua River, and in the River Lewis[37] p. 12.


                              NEWFOUNDLAND

Chromite derived from the serpentinized area in the region of Mount
Cormack, situated in the central part of the island, has been found to
contain small quantities of platinum[39].


                              AUSTRALASIA


                               AUSTRALIA

The most important occurrences of platinum in the Commonwealth are at
Fifield and at Platina, in New South Wales.

The outputs of crude platinum in Australia in recent years were all
exported to the United Kingdom as under:


                             ──────────────
                             Year. Troy oz.
                             ──────────────
                             1910       332
                             1911       470
                             1912       610
                             1913       442
                             1914       244
                             1915        56
                             1916        82
                             1917       259
                             1918       607
                             ──────────────

  _Note._—These figures do not include the osmiridium produced in
  Tasmania.

Recent imports of manufactured platinum were as under:


                              ───────────
                                      Oz.
                              ───────────
                              1910    320
                              1911    504
                              1912    318
                              1913    301
                              1914–15 223
                              1915–16  89
                              1917–18  18
                              ───────────

The question of the refining of platinum in Australia has been under
consideration for some time; so far the crude material has all been sent
to England. The outlook for future production of crude platinum in
Australia is not promising, with the exception of that of Bald Hill
district, Tasmania.

_New South Wales._—Platinum is obtained at Platina, in the Fifield
division, in the east central part of the State, from a buried gravel
channel, in which it occurs in association with gold and osmiridium. The
rocks in the vicinity of the “leads” consist chiefly of slates, but the
source of the platinum is not known[4] p. 557. These deposits were first
exploited in 1894, and from that year to 1918 inclusive, the total
output of platinum from New South Wales was 14,680 oz.[40]. The gravels
have yielded amounts of 6 dwt. platinum and 2 dwt. gold per ton, but
according to Government reports the richer deposits are nearly worked
out; mining operations are carried on with great difficulty, as there is
a great scarcity of water and a deep overburden, varying from 20 to 80
ft. in depth. It is estimated that there are 200 acres of
platinum-country available, sufficiently rich to pay, were it worked on
a large scale with an abundant supply of water[41].

A new occurrence has recently been discovered about 1 mile distant from
the old Platina deep “lead,” the platinum being associated with small
quantities of gold. The “lead” has so far been proved to extend over an
area about 1 mile in length, and from 60 to 150 ft. in width, the wash
varying in depth from a few feet to up to about 80 ft. The pay gravels,
which rest on shales and sandstones of Silurian and Devonian age,
intruded by dioritic dykes, are stated to be from 1 to 3 ft. thick. The
following analysis is representative of the crude platinum produced:


                                     Per cent.
                          Platinum       75·90
                          Iridium         1·30
                          Rhodium         1·30
                          Palladium      trace
                          Osmiridium      9·30
                          Iron           10·15
                          Silica          1·12

                              [42] p. 14.

Platinum is frequently found in beach sand deposits on the coastal
border between Queensland and New South Wales, notably at Ballina, close
to the mouth of the Richmond River; at Evans Head, further south; and at
Currumbin, near the mouth of the Tweed River. In this locality black
sands containing platinum, associated with gold, cassiterite, monazite
and osmiridium, accumulate on the beaches during stormy weather. At
Ballina and Evans Head, the platinum predominates over the gold, but at
Currumbin, further south, the gold is in the greater quantity[4] p. 557.
The minerals are present in a very finely-divided state, and separation
of the valuable metals is a matter of considerable difficulty. The
problem does not appear to have been satisfactorily solved up to the
present time, although promising experiments have recently been carried
out with screening and magnetic treatment. The deposits are,
unfortunately, very low grade.

The sources of the metals are uncertain. The platinum and osmiridium
appear to have been derived from the western edge of the Clarence coal
measures, which now exist only as fragmentary outcrops. The gold, tin
and monazite may have their origin in granite and other rocks of the New
England tableland. Chromite is present in some of the Currumbin sands,
which suggests serpentine as the probable source of platinum[4] p. 557.
Other associations are zircon, garnet, tourmaline, ilmenite, magnetite
and sapphire.

In the Broken Hill district, principally at Little Darling and Mulga
Springs Creek, platinum has been proved to extend over a considerable
area in a copper-nickel gossan, closely associated with gabbro,
decomposed gneisses and schists. In addition to platinum, the amounts of
which vary from a trace to 16 dwt. per ton, gold, silver, iridium and
palladium are also present[43]. The deposits bear some resemblance to
the nickel deposits of Sudbury, Ontario, and it is thought that here,
too, the platinum occurs combined with arsenic, as sperrylite.

_Queensland._—In addition to the beach deposits between Southport and
Currumbin, described above, platinum has been found in Coopooroo and
Wairamba Creeks on the Russell Goldfield, near Innisfail; also in the
Lucknow and Alma “reefs” of the Gympie Goldfield, where it is present in
quartz lodes with native gold, and arsenopyrite, the accompanying rocks
consisting of slates, alternating with volcanic tuffs and conglomerates;
the metal also exists in the neighbouring gold-bearing alluvial deposits
of Brickfield Gully.

Another occurrence of alluvial platinum is known at the head of the Don
River in Central Queensland[4] p. 556.

_Victoria._—Platinum occurs in the Walhalla Copper Mine, where it is
associated in a hornblende-diorite lode-formation with copper pyrites,
gold and silver. The ore is stated to contain from 2 to 7 dwt. platinum
per ton. In the Thompson River Copper Mine platinum is found in a
hornblendic rock rich in chalcopyrite.

_Tasmania._—Iridosmine has been produced from the Bald Hill district
near Waratah, in the north-western part of the state, since 1900, the
metal being obtained from placer deposits in Nineteen Mile Creek and its
tributaries, Linger-and-Die, McGinty’s and Barren Creeks, and from
Savage River. It has been located _in situ_ in the rocks of Bald Hill,
principally in serpentine, but also with chalcedony and opaline silica
in lode-formations. In the former case, it is associated with magnetite,
pyrite, pyrrhotite, nickel and gold. The iridosmine in the placer
deposits is sometimes coated with iron oxide, and is also at times found
enclosed in chromite. The following analysis in percentages, made at the
Imperial Institute, is typical: osmium, 57·09; iridium, 33·80; platinum,
0·37; ruthenium, 8·19; palladium, 0·21; gold, 0·04; iron, 0·30; copper,
trace.

Other localities in Tasmania at which osmiridium has been located are
Heazlewood River, Whyte River, Castray River, Huskisson River, Wilson
River and Boyes River; also the Badger gold diggings, west of Savage
River, and the Salisbury goldfield near Beaconsfield.

The following table gives the recent annual output of osmiridium in
Tasmania:


                        ───────┬───────┬───────
                         Year. │  oz.  │ Value
                               │(troy).│ in £.
                        ───────┼───────┼───────
                        1910   │  120  │    530
                        1911   │  272·9│  1,188
                        1912   │  778·8│  5,742
                        1913   │1,261·6│ 12,016
                        1914   │1,018·8│ 10,076
                        1915   │  247  │  1,581
                        1916   │  222·2│  1,899
                        1917   │  332·1│  4,898
                        1918   │1,607  │
                        1919   │1,669·7│ 39,614
                        ───────┴───────┴───────

_South Australia._—In the north-east part of the State traces of
platinum have been recognized by analysis as occurring in the outcrop of
a lode near Boolcoomatta. Further information on this occurrence is not
available.

_Papua._—Osmiridium, associated with small amounts of gold only, is
known to occur as alluvial in the neighbourhoods of various serpentine
areas; in the Lakekamu district, in flaky form; in the Yodda Valley, in
appearance similar to native bismuth; and in other places in shot-like
granules[44].


                              NEW ZEALAND

Platinum is only obtained commercially in New Zealand from the Orepuki
district of Southland, where it is produced by the Round Hill Gold
Mining Company as a by-product in the washing of auriferous gravels.
According to information recently supplied by the Mines Department, the
annual output of crude platinum for the last ten years has averaged 30
oz., but in view of the recent falling-off of the gold production in
this locality, the prospects of any increase in the output of platinum
seem small.

In South Island the presence of platinum has been reported on the Thames
River in quartz lodes, in a region of serpentine and diorite, and in a
pyritic lode near the Taramakau River in the district of Westland, in
close proximity to sheets of altered magnesian eruptive rocks[4] p. 557.
The platinum in the latter case occurs in association with silver, in
the proportions of about 7 parts of the latter to 1 of the former,
together with pyrite and limonite. Samples taken from the lode have been
stated to have an average content of 3 dwt. 8 gr. platinum per ton[45].

Other localities in South Island where platinum has been located are the
Taraka and George Rivers, which flow into Awarua Bay; the east coast of
Otago, in beach sands and river gravels; the Clutha River; and the
Nelson gold district.

Concentrates containing up to 2·5 per oz. per ton are reported to have
been obtained from the Parapara sub-division. Platinum in New Zealand is
often associated with gold, and the deposits are in many cases similar
to those of the Urals.




                              CHAPTER III
                  SOURCES OF SUPPLY OF PLATINUM METALS

                        (_b_) FOREIGN COUNTRIES


                                 EUROPE


                                 FRANCE

Platinum metals are not produced in France, but platinum is known to
occur at several places. In the Department of Charaste and Deux Sevres
it occurs associated with pyrite and limonite; in the Valle du Drae,
Hautes Alpes, above Chatalard, platinum occurs in tetrahedrite in
metamorphic limestone; at St. Arey, near La Mure (Isere), it occurs in
bournonite, in dolomite and altered limestone. Platinum is found in
argentiferous tetrahedrite and malachite near Presles, in Savoy[31].

As mentioned below, under Russia (p. 36), France controlled the
production of platinum in Russia before the war through the Compagnie
Internationale du Platine, due to its extensive ownership of platinum
deposits and its contracts with Russian companies.

The accompanying table gives a summary of recent imports, with countries
of origin, as far as can be obtained.


                               _Imports_

Recent imports in kilograms (42·87 troy oz.) into France of crude,
manufactured and scrap platinum, were as under:


 ─────╥────────┬───────┬────────┬───────┬────────────
 From ║ United │Russia.│Germany.│Serbia.│Switzerland.
 Year.║Kingdom.│       │        │       │
 ─────╫────────┼───────┼────────┼───────┼────────────
 1910 ║     480│  5,878│   1,104│    204│          85
 1911 ║     575│  6,895│     822│    782│         127
 1912 ║        │  5,454│     283│    144│
 1913 ║      78│  4,500│     220│       │           2
 1914 ║      63│  2,595│     161│       │
 ─────╫────────┼───────┼────────┼───────┼────────────
 1915 ║        │       │      No│details│available
 1916 ║        │       │        │       │
 1917 ║        │       │        │       │
 1918 ║        │       │        │       │
 ─────╨────────┴───────┴────────┴───────┴────────────

 ─────╥────────────────┬──────────╥──────
 From ║Austria-Hungary.│  Other   ║Total.
 Year.║                │countries.║
 ─────╫────────────────┼──────────╫──────
 1910 ║                │        44║ 7,795
 1911 ║                │       192║ 9,393
 1912 ║             271│        84║ 6,235
 1913 ║             171│        97║ 5,067
 1914 ║                │       102║ 2,921
 ─────╫────────────────┼──────────╫──────
 1915 ║      No details│available ║   188
 1916 ║                │          ║   578
 1917 ║                │          ║   578
 1918 ║                │          ║    41
 ─────╨────────────────┴──────────╨──────


                                GERMANY

Platinum has recently been discovered in Westphalia, deposits having
been found in Freudenberg, Siegen, Meschede, in Siegerland, Sauerland
and Westerwald. It occurs in a series of fragmental deposits,
including principally slates and graywackes, the latter composed of
quartz and slate, with an argillaceous cement; it is also occasionally
found in the recemented fragments which are presumably derived from
the basal granite formation, underlying the platinum series[46] p.
606. The beds are believed to be of marine origin, and are probably of
Silurian and Devonian age. The platinum, which is present in a very
finely-disseminated state, is associated with chromium, nickel,
arsenic, antimony, iron, copper, lead, zinc, silver and gold, some of
which appear to have been introduced by solutions at a stage
subsequent to sedimentation. Krusch investigated these deposits in
1914, and is of opinion, in view of the similarity of the chemical
associations with those of the Ural and British Columbian formations,
that the original source of the platinum was peridotite, or other form
of basic igneous rock. A number of samples, analysed by Krusch,
yielded values ranging from a trace to 33·5 gm. (1 oz. troy) platinum
per ton[47]. At the outbreak of war the capital necessary for
exploitation had not been raised, but in 1918 it was stated that
treatment works had been erected at Wenden[2].

As mentioned above, about 25 per cent. of the Russian output of platinum
before the war was refined in Germany, and it is known that German
capital was helping to finance the pre-war platinum operations of that
country[2].


                               _Imports_

The following is a summary of imports into Germany of crude,
manufactured and scrap platinum in kilograms (42·87 troy oz.) for the
years 1910–13:


 ─────┬────────┬───────┬────────────────┬───────┬───────┬──────────┬───────
 From │ United │France.│Austria-Hungary.│Russia.│United │  Other   │Total.
 Year.│Kingdom.│       │                │       │States.│countries.│
 ─────┼────────┼───────┼────────────────┼───────┼───────┼──────────┼───────
 1910 │     419│    846│             265│    278│    127│       216│  2,151
 1911 │     292│    895│             451│    190│    255│       239│  2,322
 1912 │     458│    642│             554│    272│     48│       307│  2,281
 1913 │     191│    683│             233│    451│    236│       230│  2,024
 ─────┴────────┴───────┴────────────────┴───────┴───────┴──────────┴───────


                                 RUSSIA

Up to the year 1914, Russia produced about 93 per cent. of the total
world’s supply of platinum, the metal being derived from extensive
deposits of alluvial sands in the Ural Mountains. The platiniferous area
extends approximately 80 miles along the central part of the chain of
mountains in the Government of Perm, and along the eastern slope, the
principal centre of the placers being at Goroblagodat, and on the
western side at Nizhni-Tagilsk.

Platinum was first discovered in the Urals in 1823, and exploitation
commenced in the following year. In 1828 the Russian Government
instituted platinum coinage, which consisted of 3–rouble, 6–rouble and
12–rouble pieces, the coins containing about 2 per cent. iridium. A
3–rouble piece weighed 10·31 gm., and the price paid by the Government
to the producers was 16_s._ 10_d._ per oz.; but owing to the subsequent
rise in value of platinum, the coinage was discontinued in 1845[48] p.
606.

The platinum industry began to develop in 1869, the price at that time
being under £5 per lb.[49], but from that year onwards the value,
although subject to considerable fluctuations, has steadily increased.
It has been estimated that since the beginning of the industry in
Russia, about 6,000,000 oz. of platinum have been recovered from
30,000,000 to 40,000,000 c. yd. of gravel.

As was explained in Chapter I, the official statistics of the Russian
output of crude platinum are considered to be low. In the following
table, the estimated and official figures of production are given for
the years 1910–17:


                             _In oz. troy_
                Year. Estimated output. Official output.
                1910            300,000          176,334
                1911            280,000          187,008
                1912            300,000          177,596
                1913            275,000          157,735
                1914            240,000          157,182
                1915            124,000          119,789
                1916             90,000           78,682
                1917             50,000

In the official statistics the Ural mining district is divided into five
principal areas. The following table shows the annual outputs by
districts in recent years:


                              _In oz. troy_
 ────────────────┬───────┬───────┬───────┬───────┬───────┬───────┬──────
    District.    │ 1910. │ 1911. │ 1912. │ 1913. │ 1914. │ 1915. │1916.
 ────────────────┼───────┼───────┼───────┼───────┼───────┼───────┼──────
 South Verkhotur │111,070│121,314│118,048│102,552│106,528│ 80,985│52,353
 Perm            │ 46,068│ 46,885│ 38,709│ 36,878│ 38,050│ 22,996│14,818
 North Verkhotur │ 11,862│ 11,362│ 13,166│ 11,376│  7,426│ 12,288│ 9,968
 Tcherdynsk      │  6,359│  5,016│  6,162│  6,109│  4,753│  3,518│ 1,542
 South           │       │       │       │       │       │       │
   Ekaterinburg  │    972│  1,040│  1,382│    816│    421│      2│
 ────────────────┼───────┼───────┼───────┼───────┼───────┼───────┼──────
 Total           │176,331│185,617│177,467│157,731│157,178│119,789│78,681
 ────────────────┴───────┴───────┴───────┴───────┴───────┴───────┴──────

Exports of crude platinum from Russia for the years 1911–15 were as
follows[15] p. 923:


         ─────────────┬───────┬───────┬───────┬───────┬───────
              To.     │ 1911. │ 1912. │ 1913. │ 1914. │ 1915.
         ─────────────┼───────┼───────┼───────┼───────┼───────
         Great Britain│  1,053│  2,107│  1,580│       │ 66,884
         France       │168,527│169,580│140,615│ 64,778│  7,900
         Germany      │ 51,612│ 50,558│ 58,458│ 17,906│
         United States│       │       │       │       │  5,266
         ─────────────┼───────┼───────┼───────┼───────┼───────
         Total        │221,192│222,245│200,653│ 82,684│ 80,050
         ─────────────┴───────┴───────┴───────┴───────┴───────

The platinum industry in Russia has always been mainly in the hands of a
few large firms of foreign countries. For a long time Johnson, Matthey &
Co., Ltd. controlled the greater part of the trade. In 1898 the Société
Anonyme de l’Industrie du Platine was established in Paris, and, by
purchasing a large number of mines, and leasing others, was able to
secure a large share in the control of the industry.

The refining of the crude platinum has been, and still is, almost
entirely in foreign hands, all but approximately 2 per cent. of the
entire output being refined abroad. In 1915 it was reported that the
construction of a refinery at Ekaterinburg was completed, which was to
be placed under Government control. The principal platinum-refining
works were formerly those of Johnson, Matthey & Co., Ltd., of England,
but early in the eighties this firm was, to a certain extent, superseded
by Heraeus & Co., of Hanau, Germany. They, in turn, in 1909, were
compelled to give first place to the Société Anonyme de l’Industrie du
Platine, of Paris, which became the chief centre of the
platinum-refining industry, a position which it held until the outbreak
of war. France at that time had a monopoly of 90 per cent. of the
Russian production. This foreign control had an unfavourable effect on
the industry, and in 1913 the Russian Government passed a law forbidding
the exportation of crude platinum. In July 1915, exportation was again
permitted, subject to a 30 per cent. _ad valorem_ export tax, and at
about the same time an order was issued forbidding the exportation of
raw platinum in quantities valued above 500 roubles (£53), the price of
the metal to be fixed by the State[15] p. 923. In February 1917 the
Government further enacted an order prohibiting the importation of drawn
and spun platinum. It was hoped by these means to encourage the
establishment of domestic refineries. In 1916 the Government fixed the
price at £16 10s. per oz. In March 1917 it was reported that the miners
were not satisfied, and later sales were reported up to £22 per oz. of
crude metal, 83 per cent. fine[50] p. 17.

According to N. Vissotzki[51], the platiniferous belt of the Urals,
geologically speaking, consists of four parallel bands striking,
roughly, north and south; the westernmost of these, made up of
crystalline schists, forms the watershed between Europe and Asia. The
next band to the east comprises olivine- and mica-gabbros,
diallage-peridotites, diorites and altered syenites—all of which have
been erupted from a great depth. The third band is made up of Lower
Devonian sedimentary rocks, shattered and buried in places by diabasic
eruptive rocks. The eastern portion of this band is formed of eruptive
rocks of deep-seated origin which may be gneissose granites. The fourth,
or most easterly band, is composed of ancient rocks, which have been
eroded by the advancing sea of Lower Tertiary age.

The area emerged from the waves as early as the Carboniferous period;
consequently the accumulation of platinum, and in some localities of
gold, in the surface-deposits, were not swept away. They were
concentrated later on in the alluvia—perhaps at the time of the most
intense glaciation, probably in the Pleistocene.

Throughout the Urals, the primary source of the platinum is associated
with the eruptive basic rocks, among which the platiniferous and
auriferous dunite forms three great masses. The principal outcrops of
platiniferous dunite and platinum-bearing alluvia are connected with the
second of the four parallel bands mentioned above. Towards the south,
the band becomes discontinuous, and finally dies out altogether. Here a
few outcrops of platiniferous olivine-rock contain a small percentage of
platinum, with osmiridium and other members of the group associated with
it.

The two principal platinum-producing districts are in the central Urals,
and are: (1) The Shuvaloff Estates, Isov district, on the River Iss,
near Goroblagodat. (2) The Demidoff Estates, Nizhni-Tagilsk district, on
the Martian River in the South Verkhotur district. Prior to 1879 the
latter field furnished the larger part of the platinum, but since then
the former has been the most productive, and now supplies about 80 per
cent. of the total output. The whole of the platinum is derived from
gravel deposits, which are usually auriferous, and associated with
dunite.

_The Isov district._—Platinum is concentrated in the channels of the
Rivers Iss, Veeya and Tura. In the north of this region it is obtained
from the Sosnovki, Kytlymi, and Mala Kosva Rivers; further north again,
platinum occurs with gold in the Vagran River, and in the system
comprising the Rivers Lobva, Niasma, Lialia, Aktai, Emerlo and Talits,
the gold here being predominant. Other sources of supply of platinum and
gold in this district are on the Ivdevl River. In the south of the area,
platinum deposits are worked on the tributaries of the Tagil, Salda,
Imiaun and Tura Rivers[15] p. 921.

_The Nizhni-Tagilsk district._—The richest placers occur in the valleys
of the Visim, Martian, Sisim, Chaush and Cherna Rivers. Further south,
platinum is found with gold in the gravels of the Nevian, Verkhne-Iset,
Bilenibaev, Alapaev, Sysert, Kyshtym and Mias areas, and also in the
Tanalyk, Sakmar and Urtazym Rivers.

Other localities of smaller importance are the Nikolae Pavdinsk and
Rastes districts in the northern Urals, and the Systersk mining
district.

The placers are derived from country rock, made up of serpentine gabbro,
diallage and olivenite, the principal associated minerals being quartz,
zircon, ilmenite, chromite, magnetite, spinel, native gold and
palladium. Gold is present in the concentrate in very variable
quantities, and sometimes contains silver, but the latter generally
occurs in combination with palladium. The crude platinum usually
includes some iridium, rhodium, ruthenium and iron.

The basic igneous rocks, from which the platinum is derived, are exposed
in the form of discontinuous elliptical outcrops near the summits of the
Urals, particularly on the western side of the mountains. These outcrops
attain larger dimensions in the northern and central Urals than further
south. The process of concentration of platinum in the gravels has
clearly extended over a very long period of time, and it is probable
that the richer gravels have been reconcentrated, perhaps several
times[52] p. 299. Platinum nuggets are rarely found, but three of large
size were discovered in the Nizhni-Tagilsk district, their weights
respectively being 25½ lb., 21 lb., and 11½ lb.

Duparc, in a brief description of the geology of the deposits, states
that they are essentially of magmatic origin. The structure of the rock
is in the nature of concentric bandings; the felspathic rocks at the
outer edge gradually grade into the intermediate stage of pyroxenes,
until the central dunite is reached, composed of olivine and chromite.
The richness of the gravels is in proportion to the size of the dunite
deposits, and to the extent of erosion of these rocks. According to
Duparc, platinum ore derived from a pyroxenite source usually contains
high percentages of platinum and palladium, but low percentages of
osmium and iron. The same writer estimated in 1916 that the reserves
were sufficient for about twelve years, provided that the same methods
of working and rate of extraction were employed during that period[53].

The amount of the platinum in the wash is very variable. The average
yield was formerly over ½ oz. per c. yd., but latterly, owing to the
gradual exhaustion of the richer deposits, the average returns have not
exceeded from 2 to 3 dwt. per c. yd. The crude metal assays about 83 per
cent. platinum, from 5 to 7 per cent. osmium and iridium, with small
amounts of ruthenium, palladium, and gold, and about 10 per cent.
impurities, mostly iron and copper[54]. The thickness of the pay gravels
varies from 3 to 6 ft., and about 4 ft. may be taken as the average
width, the overburden running from a few to over 60 ft. The extent of
the productive area is about 170 sq. miles, and from 15,000 to 20,000
miners were employed before the war[4] p. 558. It has been noticed that
the platinum deposits are characterized by their uniformity, of course
not being so sinuous in direction as gold deposits.

In former times mining was entirely carried on by primitive methods with
hand labour, but the utilization of dredges has steadily increased,
since their introduction in 1900. In 1909, 13 per cent. of the total
production was obtained by dredging, and in 1914 this percentage rose to
one-third of the total output. The season during which dredges may be
employed extends on the average from the middle of April to the middle
of October. In the South Verkhotur and Perm areas dredges have been used
in the large enterprises; but at the small mines the working is very
primitive, and carried on largely with the help of _starateli_, or
tributers. In 1914 a modern 7½ c. ft. dredge was installed on the
Nikolaie-Pavdinsk Estate.

In mines where dredging is not in use, the gravels are mined by open
cuts, or, if the overburden is thick, shafts are employed. The former
method is much preferred, both on account of its relative cheapness, and
also because it is possible to obtain a better clean-up of the bedrock.

The usual types of stationary plant in use include the _botchka_, or
conical revolving screen; the _tchaska_, or puddling machine, with a
bottom of perforated iron plates; and the _boronka_, or conical screen,
on which the stones and clay are turned over by a double rake[55]. The
gold is removed by amalgamation with mercury in wood, iron or porcelain
bowls. Special methods are in use in certain parts of Russia for working
the deposits during the winter. The workings are allowed to freeze, and
the frozen ground is mined after being partially thawed by means of wood
fires. The method is simple, but care must be taken to ensure that the
thawing does not proceed too far, otherwise the ground collapses, and
the workings become flooded. The method is suitable for depths to 30
ft., and in localities where the snowfall is comparatively slight.

Latest reports from Russia indicate that no dredges are now working
there, the platinum being produced by hand methods only.

Some interesting experiments were recently carried out by V. N.
Chorzhevski in the Nizhni-Tagilsk district, with a view to testing the
commercial possibility of mining platinum _in situ_. The metal here
occurs, in association with chrome iron ore, in dunite rock, which in
this region extends over an area of 11½ sq. miles. The platinum appears
to be present in quantities directly proportional to the amount of
chromite in the rock. The dunite is first ground under runners; the
chromite slack is separated from it; and after this has undergone a
second grinding, the metal is separated by washing[56]. An experimental
test, carried out in March 1917, is stated to have produced over 200 oz.
platinum from 9,720 lb. chromite slack. Another experiment with 3,600
lb. of grey slack, “or fines,” consisting chiefly of undecomposed dunite
obtained from the dredges, is reported to have yielded ⅓ oz. of
platinum.

_Lapland._—Platinum occurs associated with chromite and diamonds, in
alluvial deposits on the Ivalo River. It is believed to be derived from
serpentine rock, of which the neighbouring country is largely
composed[4] p. 556.

_Finland._—Platinum has been found in the south in a lode-formation
containing quartz, siderite, calcite and dolomite. Gold and carbonate of
copper are also present in small quantities.[4] p. 557.


                           PLATINUM CURRENCY

In a dispatch to the Great Powers on February 26, 1920, the Soviet
Government promised to withdraw the decree annulling Russia’s foreign
debt, to pay arrears of interest, and giving as a guarantee to an
Anglo-American syndicate certain important platinum and silver-mining
concessions, in return for which the abandonment of intervention in
Russia’s internal affairs was demanded. To be used in payment of foreign
purchases, the Government was about to issue “platinum” credit notes of
50, 100, 500, and 5,000 roubles, the issue to be limited to 65,000,000
roubles, and backed by platinum reserves of 37,500,000 roubles. The
Government would be ready to convert the platinum reserves into coin if
required[57].


                                 SPAIN

Promising deposits of platinum have recently been reported at Ronda, in
the province of Malaga. Domingo de Orueta, a Government geologist,
having noticed the similarity of the geology of this district to that of
the platiniferous deposits of the Urals, proceeded, a few years ago, to
explore the area systematically, and was soon rewarded, in the discovery
of the metal. The deposits, which are alluvial, extend along the Verde
and Guadaiza rivers, and are derived from serpentine and peridotite
rocks, the latter composed principally of rhombic pyroxene, with some
spinel and some dunite. Chromite occurs in association with the
platinum. The pay gravels contain about 8 gr. platinum per ton, and are
stated to have an average thickness of 5 ft., the depth of overburden in
the Guadaiza area, where apparently the richer gravels are found, being
about 33 ft., as compared with 49 ft. in the Verde locality[10] p. 547.
The Spanish Government have taken over the exploitation of these
deposits, and no public prospecting, without Government permission, is
allowed.

Platinum is known to exist in a number of other localities in Spain,
especially in the northern districts; but so far as is known, it occurs
in very small quantities of no commercial importance. The metal has been
recognized in the following rivers: Minho, Luna, Sil, Orbigo, Gallego,
Cinca Darro and Lower Jenil, where it occurs in the concentrate sands,
accompanied by magnetite, ilmenite, zircon and, frequently, gold[58].


                                  ASIA


                                ARMENIA

Platinum, in association with gold, is reported to occur in the district
of Batum and Sasun, on the Charokh River[46] p. 610.


                                 BORNEO

Platinum was discovered in south-eastern Borneo in 1831, in the gravels
of Gunung Lawack, but for a long time the natives were ignorant of its
value. In recent years it has been obtained on a small scale as a
by-product in the process of gold-washing, carried on in the province of
Tanah-Laut, in the south-eastern extremity of the island[59]. The
deposits occur in streams, which rise in the Bobaris Mountains, where
the country rocks are composed of schists and gneisses, intruded by
serpentine gabbro and diorite dykes[52] p. 298. Platinum has, however,
not yet been located _in situ_. In addition to gold, the platinum is
associated with osmiridium in the gravels, the two former being
frequently found intimately intergrown. The platinum content of the
native metal has been found by a number of analyses to vary from about
57 to 83 per cent., and that of osmiridium from 0·18 to 10·07 per
cent.[60].

The rare mineral _laurite_, a sulphide of ruthenium and osmium, was
discovered in these deposits.

According to L. Hundeshagen[61], the platinum occurring in the diamond
placers of western and south-eastern Borneo is in the form of thin
scales, ranging from 0·1 to 1·0 mm. in length. These platinum scales
contain from 3·8 to 4·5 per cent. of copper, evidently as an alloy.


                                 CHINA

In the Uryanchai district of Mongolia, situated on the Russian border,
deposits of auriferous gravels have been worked on a fairly extensive
scale for some time past. It was announced a few years ago that platinum
and iridium had been found in appreciable quantities, associated with
the gold, some large platinum nuggets being obtained from this region in
1911. Although no attempt at commercial development has yet been made,
the prospects of profitable extraction appear to be hopeful. Extensive
outcrops of olivine rocks have been noticed in the vicinity, and the
nature of the occurrence is stated to bear some resemblance to that of
the platiniferous fields of the southern Urals[8] p. 107.


                                 JAPAN

Platinum occurs in the Yubari-garva, Pechau and other rivers in the
province of Hokkaido. It is also found in Nishi-Mikawa, province of
Sado. In the former locality gold and iridosmine are associated with the
platinum, and in the latter gold and iron sands are present[62]. In no
case has the metal been traced to its parent source. In the Hokkaido
deposits the average quantity of platinum present is only 2 or 3 per
cent. of the iridosmine content. It is possible that further exploration
in these areas will reveal occurrences of greater importance[9] p. 597.


                                SUMATRA

Platinum is obtained at Sipongi, where it occurs with wollastonite and
grossularite in limestones and schists, near intrusions of granodiorite
and augite diorite. Gold is also present.

L. Hundeshagen[61] is of opinion that the present ore deposit was
originally a layer, or a big lens, of limestone embedded in the old
schists, which has, by apophyses of granite, been altered into garnet
and wollastonite, being at the same time, or very soon afterwards,
mineralized by hot solutions carrying copper, gold, platinum, etc. A
sample of slightly decomposed wollastonite with no copper, or only
minute traces of that metal, proved to be richest in platinum, the assay
showing 6 gm. of platinum per 1,000 kg., while samples with 2 to 10 per
cent. of bornite and malachite contained only traces of platinum; and
none could be detected in auriferous garnet, poor in wollastonite. About
10 to 25 metres from the outcrop the concentrated river sand shows small
particles of whitish crystalline gold and rounded grains of white
platinum, the latter varying from 0·1 to 0·3 mm. in size.


                                 AFRICA


                            CONGO FREE STATE

In the Katanga district, platinum and palladium have been reported to
occur in certain alluvial gravels, accompanied by gold and silver. One
sample from this locality is stated to have yielded the following
amounts per metric ton: 3·4 gr. platinum, 12·3 gr. gold, 8·3 gr. silver.
It has also been located _in situ_ in sandstones containing gold.


                               MADAGASCAR

Platinum is produced on a small scale as a by-product in alluvial gold
mining on the Vatana River, near the village of Ambia, in the Vatomandry
district. Traces of the metal have also been found in auriferous gravels
in the regions of Fenerive, Marolambo, and Vandrozo, over an area
extending along the eastern side of the island for a length of about 450
miles. The platinum is apparently derived from the decomposition of
pegmatite. It is rarely found pure, being usually coated with iron
oxide, and strongly magnetic, a property which is utilized in the
process of separation from the gold[63].


                             NORTH AMERICA


                                 MEXICO

Platinum has been shown to exist in the states of Guerrero and Hidalgo
in deposits of ferrous clays, which are of undoubted sedimentary origin,
and are apparently laterites. The metal exists in a very finely
disseminated state, invisible to the naked eye[64].


                             UNITED STATES

At the beginning of the war there was a considerable shortage of
platinum in the country, caused partly by the falling-off of the
imports, and in part owing to the increased demand in connexion with
munition manufacture.

California is the principal producer of crude platinum, and in 1917 this
State supplied 460 oz. out of the total output of 605 oz.; with the
exception of a few ounces from the State of Washington, Alaska and
Oregon provided the balance.

A considerable quantity of foreign crude and manufactured platinum is
imported annually, as shown in the following tables:


        _Imports of Manufactured Platinum into the United States_

                              (In troy oz.)
 ──────────────────────┬──────┬──────┬──────┬──────┬──────┬──────┬──────
                       │1912. │1913. │1914. │1915. │1916. │1917. │1918.
 ──────────────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 _From British         │      │      │      │      │      │      │
   countries_:         │      │      │      │      │      │      │
   Canada              │   777│   582│    55│   139│   511│   332│   253
   United Kingdom      │19,169│16,595│ 6,476│ 7,692│ 9,513│ 3,195│   357
   Other British       │      │      │      │      │      │      │
     countries         │     4│      │      │      │     5│      │    25
 ──────────────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 Total, British        │      │      │      │      │      │      │
   countries           │19,950│17,177│ 6,531│ 7,831│ 9,569│ 3,527│   635
 ──────────────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 _From foreign         │      │      │      │      │      │      │
   countries_:         │      │      │      │      │      │      │
   France              │25,723│24,519│16,570│ 3,480│ 3,395│ 2,507│   814
   Germany             │22,673│29,075│30,015│ 2,350│    10│      │
   Netherlands         │      │      │      │      │   159│      │
   Norway              │      │      │   258│      │      │   120│
   Russia (European)   │      │      │   815│      │      │      │
   Colombia            │      │      │      │   480│      │   207│ 1,665
   Other foreign       │      │      │      │      │      │      │
     countries         │      │      │      │    63│   512│    57│     3
 ──────────────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 Total, foreign        │      │      │      │      │      │      │
   countries           │48,396│53,594│47,658│ 6,373│ 4,076│ 2,891│ 2,482
 ──────────────────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
    Grand total, oz.   │68,346│70,771│54,189│14,204│13,645│ 6,418│ 3,117
 ──────────────────────┴──────┴──────┴──────┴──────┴──────┴──────┴──────


              _Imports of Crude Platinum into United States_

                               (In troy oz.)
 ───────────────┬────────┬──────┬──────┬──────┬──────┬──────┬──────┬──────
                │1911[N].│1912. │1913. │1914. │1915. │1916. │1917. │1918.
 ───────────────┼────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 _From British  │        │      │      │      │      │      │      │
   countries_:  │        │      │      │      │      │      │      │
   Canada       │     554│    45│   314│   535│   139│    91│    25│    76
   United       │        │      │      │      │      │      │      │
     Kingdom    │  28,153│19,951│ 8,368│ 7,084│ 6,805│36,703│ 1,561│ 1,073
   Other British│        │      │      │      │      │      │      │
     possessions│        │     7│      │      │     5│      │      │     —
 ───────────────┼────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 Total, British │        │      │      │      │      │      │      │
   countries    │  28,707│20,003│ 8,682│ 7,619│ 6,949│36,794│ 1,586│ 1,149
 ───────────────┼────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 _From foreign  │        │      │      │      │      │      │      │
   countries_:  │        │      │      │      │      │      │      │
   France       │  44,964│10,178│ 7,284│ 4,921│ 3,507│13,014│    52│   166
   Germany      │  37,041│15,335│23,345│15,105│ 2,366│      │      │     —
   Norway       │        │      │   200│   442│   285│   302│      │     —
   Panama       │        │      │      │   160│   105│    92│    12│   372
   Brazil       │        │      │      │      │      │   118│   103│    27
   Chile        │        │     9│      │      │      │      │   766│     3
   Colombia     │   5,503│ 6,627│10,461│12,387│13,121│25,588│21,071│25,365
   Other foreign│        │      │      │      │      │      │      │
     countries  │      17│    13│      │      │     1│   103│    99│21,663
 ───────────────┼────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 Total, foreign │        │      │      │      │      │      │      │
   countries    │  87,525│32,162│41,290│33,015│19,385│39,217│22,103│47,596
 ───────────────┼────────┼──────┼──────┼──────┼──────┼──────┼──────┼──────
 Grand total,   │        │      │      │      │      │      │      │
   oz.          │ 116,232│52,165│49,972│40,634│26,334│76,011│23,689│48,745
 ───────────────┴────────┴──────┴──────┴──────┴──────┴──────┴──────┴──────

Footnote N:

  Including manufactured platinum.

In 1917, 38,831 oz. of refined platinum metals, of which 7,384 oz. is
believed to have been of domestic origin, were recovered from alloy with
other metals, and 72,186 oz. were obtained from the refining of scrap
metal, and sweepings. The shortage was also to some extent relieved by
the receipt from Russia early in 1918 of a special consignment of 20,922
oz. of crude platinum, which had been collected in 1917 by the
Russian-English Bank, and which was taken out of Russia by F. W. Draper
and delivered to the United States Government. It yielded 17,640 oz.
platinum, 64·75 oz. palladium, 182·11 oz. iridium and 48·56 oz. of
rhodium, a total of 85·725 per cent. of platinum metals, slightly above
the usual 83 per cent.[65].

_Alaska._—The first production of platinum in Alaska was in 1916, in
which year about 12 oz. were shipped to the United States. In 1917 the
output rose to 81 oz., of which 66 oz. were obtained from the Seward
Peninsula and 15 oz. from the Copper River country.

In 1918 an increased output of 135 oz. was partly obtained from alluvial
deposits and partly as a by-product in the treatment of copper ore of
the Salt Chuck mine, Ketchikan[66].

This mine is a palladium-copper mine containing mainly bornite with a
little chalcopyrite, and the alteration products covellite and
chalcocite, the metals present being, besides copper and palladium,
gold, silver and platinum. The ratio of palladium to platinum averages
50 to 1. The concentrates produced, representing about 3½ per cent. of
the weight of the ore, contain: copper, 40 per cent.; gold, 1·2 oz.;
silver, 5·3 oz.; and platinum metals, 3·15 oz. per ton[67].

In the Seward Peninsula the larger portion is derived from placer
deposits in Dyme Creek, Koyuk district, where the gravels are primarily
worked for gold, 1 oz. platinum being obtained for every $5,000 worth of
gold. In 1918, 56 oz. were recovered. Bear Creek and Sweepstake Creek
have also supplied small quantities of platinum, and a little is derived
from placers on Boob Creek, in the Tolstoi district [50] p. 19.

A possible source of platinum appears to lie in the neighbourhood of the
Red Mountain, on the Kenai Peninsula. The mountain is composed of
fine-grained dunite, in which abundant chromite occurs. Up to 1917 no
placer mining had been attempted in this locality[68].

In the Goodro Mine, at the head of Kasaan Bay, Prince of Wales Island,
were found in 1918 both platinum and palladium, the latter in greater
amount, and carried in bornite and chalcopyrite; some chalcocite and
covellite are present also in the ore. The copper minerals are
disseminated through pyroxenite, and the country rock consists of
limestones, slates and other sedimentaries. The platinum content is
small, but regular, whilst the amount of palladium present is
proportional to the amount of copper, there being about 1 oz. of
palladium to every 8 to 12 per cent. (units) of copper[69].

A Bill has been introduced into Congress providing for the incorporation
of the United States Platinum Corporation, with capital stock of
$30,000,000, the object of which is to secure a concession from the
Government of land areas in Alaska containing platinum sands, and to pay
for such privilege, as a royalty or subsidy, one-eighth of the net
profits obtained from the working of the concession[70].

_California and Oregon._—Platinum has been proved to exist over a wide
area in placer deposits associated with gold, but the proportion of the
platinum metals to the gold is usually small. Platinum is obtained from
sands in streams rising in the belt of serpentine rocks in central
California, and from the serpentine areas in the Siskiyou and Trinity
counties in the north-west of the State, which continue north-east into
Curry, Josephine and Jackson counties in south-western Oregon[52] p.
300. The sources of the platinum obtained along the foot-hills of the
Sierra Nevada were old stream channels on the western slopes of the
mountains, which are now buried beneath lava several hundred feet deep.
These “deep leads” are also mined by drifting for their gold and
platinum contents, and in a few cases a fair amount of the metals is
extracted from them. Some platinum is obtained by hydraulic mining, but
this is carried on with difficulty, owing to the prevailing scarcity of
water[50] p. 18.

Platinum occurs in black sands found on the Pacific coast in the
counties of Coos, Curry and Josephine, Oregon and Del Norte, California.
Formerly these beach deposits were rich in platinum, but at the present
small quantities only are obtainable after stormy weather. This area has
recently been examined by the United States Bureau of Mines, but the
results were disappointing.

In California most of the output of platinum is produced by dredging for
gold in the Butte, Calaveras and Stanislaus counties[50] p. 19. In
Trinity county mining is in progress on the Trinity River, about 4 miles
below Junction City, by the Valdos Dredging Co. The output from this
source for sixteen months in 1916–17 was stated to be 1,950 gm.
Platinum, with gold and osmiridium, is also obtained on the Yuba River,
about 12 miles east of Marysville in Yuba county, by the Yuba
Consolidated Goldfields[10] p. 540. Some alluvial platinum has been
recovered at the Bean Hill Gold Mine, situated 12 miles south-east of
Placerville, and this locality is at present under investigation[71].
Californian metal contains from 25 to 45 per cent. iridium. Its origin
is believed to be the serpentine- and olivine-bearing rocks of the
Sierra Nevada and other ranges.

In Oregon, in addition to the platinum obtained from the beach deposits
near Bullards and Marshfield[50] p. 20, it occurs in placer deposits,
rich in chromite, in south-west Oregon, the principal output being
derived from the Waldo district.

Platinum also exists in small quantities in streams in the neighbourhood
of the Blue Mountains, eastern Oregon, where the Powder River Gold
Dredging Co., in Sumpter district, produces on a small scale. Other
platiniferous localities in eastern Oregon are the Granite and Canyon
districts, and Spanish Gulch in Wheeler county[10] p. 541.

_Colorado._—Platinum is known to exist in the black sands from Clear
Creek. Its presence has also been reported in the gold gravels of the
Iron Hill placer at Como, where it occurs mechanically combined with
magnetite. Another occurrence recently discovered is in a vein worked by
the Rollcall Mining Co., near Villa Grove. An assay of material from
this vein, taken at a depth of 1,500 ft., showed the following values:
gold, 3·2 oz.; platinum, 5·09 oz.; silver, 3·05 oz.; and copper, 3·5 per
cent.[9] p. 592.

_Nevada._—In 1909 the occurrence of platinum in Clark county was noticed
by the United States Geological Survey to be in association with copper,
nickel and cobalt ores from the Key West and Great Eastern Mines, near
Bunkerville. The ore bodies are contained in pegmatites and basic
intrusions, which carry pyrrhotite and chalcopyrite, the platinum
content in the ore averaging about 0·2 oz. per ton[72].

In 1914 platinum, with palladium, was discovered at the Boss Gold Mine,
situated 10 miles west of Goodsprings, in Clark county. The mine was
originally worked for copper, and later for its copper and gold
contents. The country rock consists of limestone of middle Carboniferous
age, intruded by sills of quartz monzonite porphyry, the ore bodies
occurring in a fault zone in the limestone. The copper ores comprise
mainly chrysocolla and malachite, and contain traces only of platinum.
The gold ore occurs in a fine-grained siliceous matrix, containing a
bismuth-bearing variety of _plumbo-jarosite_ (a hydrous sulphate of iron
and lead). The rare metals are present in the free state, being
apparently alloys of gold, platinum and palladium[73].

In 1919 the Boss Mine shipped $22,365 worth of platinum-bearing ore[74].
A plant of 300 tons monthly capacity has recently been erected at Los
Angeles, California, for the treatment of its complex ores, which
average 7 per cent. of copper, 4 per cent. bismuth, and 1·0 oz. of
platinum and palladium, 0·75 oz. of gold, and 3 oz. of silver per ton.
The pulp from ore pulverized to 80 mesh is agitated with sulphuric acid
(2 per cent.). The acid solution contains the copper and about 20 per
cent. of the platinum. The copper is precipitated as cement copper,
together with the platinum, by means of scrap-iron. The remainder of the
platinum, together with the gold and silver, is first leached with, and
then precipitated from, a neutral solution of calcium chloride. The
inventors of the process claim that approximately 92 per cent. of the
copper, 96 per cent. of the platinum metals, gold and silver, and over
90 per cent. of the bismuth are recovered by this process[75].

Metals of the platinum group have recently been shown to exist in small
quantities in the ore of the Oro Amigo Mine, situated between 1 and 2
miles north-east of the Boss Mine. This ore differs from that of the
Boss Mine, in that bismuth and plumbo-jarosite are absent. According to
H. K. Riddell, the platinum metals content averages from a trace to 0·1
oz. per ton of ore.

_North Carolina._—At Mason Mountain, in Mason county, platinum occurs
associated with rhodonite, garnet, biotite and iron sulphides in
metamorphic deposits.

_New York._—It was reported a few years ago that platinum existed in
large quantities in alluvial sands of the Adirondack region. J. M.
Clarke, the New York State Geologist, examined the occurrence in 1917,
and found that platinum was present in traces only, the deposits being
of no economic importance [10] p. 541.

_Pennsylvania._—At Lancaster county platinum is associated with pyrite,
chalcopyrite and galena in mica-schist, and also at Boyertown in black
Triassic shale.

_Washington._—The production of platinum on a small scale has been
reported from beach deposits at the mouth of the south fork of the Lewis
River near Yacolt, and also on beaches southward from the Straits of
Juan de Fuca[10] p. 542. The metal has also been located at various
places in the Cascade Mountains in the central part of the State.

_Wyoming._—Palladium and platinum, in the proportion of 3 to 1, are
obtained at the Rambler Mine, in Albany county, the metals occurring as
sperrylite in copper ore, contained in the kaolinized portion of a
dunite dyke, intrusive into granite gneiss. The ore consists of
covellite, chalcocite, chalcopyrite and tetrahedrite, with nickel and
gold[76]. It is stated that the platinum and palladium contents vary
directly with the percentage of copper present, a typical assay giving
the following values: copper, 5 per cent.; gold, 0·02 oz.; silver, 1
oz.; palladium, 0·4 oz.; and platinum, 0·6 oz. per ton[77].

_Utah._—Platinum and gold in very fine particles occur in the Green
River, east of Vernal; also in the Colorado River, near Hite, below the
mouth of the Green River. Attempts to mine these deposits have so far
proved unsuccessful, due largely to the inaccessibility of the region,
as well as the finely-divided condition of the platinum[42] p. 11.


                             SOUTH AMERICA


                                 BRAZIL

José Vieira do Couto, in 1801, first pointed out that platinum occurs in
the sands of the Lages River, near Conceiçao, Minas Geraes. According to
E. Hussak[78], platinum in that region occurs only in the alluvium of
rivers having their rise on the eastern slope of the Serra do Espinhaço.
The platinum is accompanied by black pebbles of quartz-tourmaline rocks,
magnetite, hematite, rutile, octahedrite, xenotime, monazite, senaite,
pseudomorphs of rutile after octahedrite (_captivos_), zircon and gold,
which is sometimes of a copper-red colour (palladium-gold). Palladic
gold was formerly called _ouro branco_ (white gold), by the miners.

At Condado, further north on the eastern slope of the same Serra,
platinum also occurs with very similar associations. The platinum from
both localities occurs in bunchy, mammillated and globular forms,
concave within, with thin walls, having a radiated fibrous structure
under the microscope. It is frequently in thin foliated crusts, having
the characteristic structure of hematite. It was accurately described by
Wollaston in 1805 and 1809. Hussak thinks the primary formation was an
olivine rock, or gabbro, while the platinum is secondary, having been
most probably re-deposited from solutions resulting from the
decomposition of platiniferous pyrites or of sperrylite (PtAs_{2}),
minerals derived, possibly, from the neighbouring schistose quartzite,
or from the overlying conglomeratic quartzite.

The platinum of Condado, although comparable, as regards density, to the
Russian platinum, is very rich in palladium, is non-magnetic and
contains practically no iron. An analysis by G. Florence gave the
following percentages: insoluble residue, 0·92; platinum, 73·99;
iridium, 0·08; palladium, 21·77; iron, 0·10 (= 96·86), undetermined
(rhodium and osmium), 3·14.

In the Rio Abaeté, Minas Geraes, platinum—very different in appearance
and chemical composition from that of the Serra do Espinhaço—occurs in
placer deposits, associated with gold, diamonds and the following
minerals: rolled pieces of a hydro-phosphate of barium and aluminium
(_gorceixite_ = “marumbé” of miners), garnet, almandite, pyrope,
ashy-blue oxide of titanium (_bagageira_—regarded as a good indicator
for diamonds), magnetite, chromite and calcium-titanate (_perovskite_).
Pyroxene-olivine rock, a typical picrite-porphyry, rich in perovskite,
and granular magnetite rocks, rich in titanium, have been observed by
Oliveira in the vicinity. Hence it is highly probable that the platinum,
as in the Urals, came from olivine rocks. The platinum occurs in thin
laminæ, strongly rolled, and, rarely, in cubical crystals with the edges
visibly rounded. It is strongly magnetic and contains no palladium.
Minute crystals of osmiridium may occur with those of platinum, and in
the platinum particles are found regular inclusions of osmiridium, as at
Nizhne Turinsk, in the Urals, the platinum of which locality it
resembles in chemical composition, magnetic properties and crystalline
structure. The following analysis shows the percentage and composition
of a general sample: insoluble residue, 7·57; iron, 9·62; palladium,
trace; copper, trace; platinum metals, 82·81.

The auriferous alluvial of the Cuyabá and Coxim rivers in the southern
part of the State of Matto-Grosso, also contain some platinum. According
to Luiz Caetano Ferraz[79], platinum occurs in the River Coxipó-Mirim,
where golddredging is carried on, combined with palladium, iron, osmium
and iridium in small spherical grains, flattened on one side, of a
brilliant white colour and strongly magnetic. It is found in alluvial
deposits, associated with various kinds of quartz and oxides of iron,
marcasite, arsenopyrite, rutile, anatase, almandine, garnet, black
tourmaline, monazite, staurolite, white topaz, sphene, cassiterite,
wolfram, graphite, galena and native silver.

In the State of Bahia, platinum has been found in Ituassú, Feira de S.
Anna and Serra do Assuruá, and it is said to occur at Sâo Bartholomeu,
and in the Serras do Pitango and Macahubes[80].

Platinum also occurs in Brazil as rare disseminations in the
gold-bearing _jacutinga_, intercalated in the itabirites (e.g. at Gongo
Socco Mine, long since abandoned). The jacutinga occurs as narrow bands
and nuclei in the itabirites, containing a high percentage of gold, with
much talc, clay and pulverulent pyrolusite. As accessory minerals
zircon, rutile, cassiterite and tourmaline occur. Hussak thinks that the
gold-bearing jacutinga has been derived from altered pegmatite veins.

From analyses made by Johnson (1833–41) on the Gongo Socco bullion, it
would appear that the percentages of silver and platinum decreased while
those of copper and palladium increased with depth (Henwood). The
percentages of palladium varied from 3·89 to 4·80, and that of platinum
from 0·04 to 0·12.

At Candonga, gold occurs in an eruptive rock rich in magnetite enclosed
in itabirite, and is probably of contact-metamorphic origin. The gold
occurs in grains of high standard, and with it are found fine indented
scales of palladic gold, of a bright copper-red colour.

At Itabira do Matto Dentro gold occurs in jacutinga, lying between a
micaceous iron schist, rich in quartz, and an enormous solid bed of
itabirite. The palladium-gold may be copper-red, dark-brown or
silver-white in colour. Native platinum also occurs with the gold.

Grains of platinum have also been found in the most northerly of the
auriferous lenticular masses, which occur near the Bruscus River, near
Pernambuco, in Cambrian crystalline schists. The matrix is a coarse
white quartz containing small quantities of the arsenides and sulphides
of iron, and the sulphides of copper, lead and zinc.

Platinum, although widely distributed in Brazil, occurs in such small
quantities that so far there has been no production; but in the near
future richer and more extensive deposits may be discovered, or it may
be found practicable to win the metal from those already known, as an
important by-product.

Palladium-gold, or _porpezite_, is a natural alloy of palladium and
gold, and may contain up to 10 per cent. of the former metal. It is
found in Brazil, in gold-washings, and also in the gold-bearing
jacutinga reefs at Gongo Socco, Candonga and Itabira do Matto Dentro. In
1870 Henwood showed that the palladic gold from Gongo Socco contained,
to a moderate depth from surface, from 0·04 to 0·12 per cent. of
platinum. (Palladium-gold has also been reported from gold-washings in
the Caucasus, near Batoum.) Ruer concludes, from an examination of the
freezing-point curves of artificial alloys of gold and palladium, that
these alloys form a continuous series of mixed crystals, and that there
is no indication of chemical combinations[81].


                                COLOMBIA

This republic is the second largest producer of platinum in the world,
and in pre-war years supplied about 5 per cent. of the world’s total
output. Owing to the decline of the Russian supply, and the increased
demand for the metal, the industry has in recent years received a
considerable stimulus, and in 1916 Colombia’s production rose to
approximately one-third of the Russian output.

Platinum was first introduced into Europe from Colombia in 1735,
although the metal was known in America for some time previously[48] p.
608. In 1810 the value of platinum stood at $5 to $6 (U.S.) per oz., and
in 1823 the price had further dropped to from $3 to $4 per oz. As a
result, platinum was rejected as waste in the operation of refining gold
by the “dry-blowing” system. Later, when platinum became valuable, much
of this dumped metal was recovered, notably in Quibdo, the capital of
the Chocó district, where much gold-refining was carried on.

The following table gives the outputs of crude platinum from Colombia,
in recent years, principally produced in the Chocó district:


                        Year.    Oz. (troy).

                        1911  12,000
                        1912  12,000
                        1913  15,000
                        1914  17,500
                        1915  18,000
                        1916  25,000
                        1917  32,000
                        1918  35,000 (estimated)

The larger portion of the production is shipped to the United States,
the exports to that country for the years 1910–18 being as follows:


                           Year. Oz. (troy).

                           1910        1,600
                           1911        5,503
                           1912        6,627
                           1913       10,461
                           1914       12,387
                           1915       13,121
                           1916       25,588
                           1917       21,278
                           1918       27,030

The crude platinum is estimated at 84 to 85 per cent. fine. The price in
1917 fluctuated from £16 to £20 10_s._ per oz., the average for the year
being nearer the latter amount.

During 1918 the United States Government fixed the price at $105 per
oz., which stimulated production.

The deposits are alluvial, and consist of re-concentrates of older
gravels. The principal source of supply is at the head of the San Juan
River, which enters the Pacific Ocean north of Buenaventura, the richest
deposits occurring in the Condoto, Opagado and Tamanal Rivers,
tributaries of the San Juan[82]. Platinum is also obtained in the Upper
Atrato River, which flows northward to the Caribbean Sea. It is nearly
always found associated with gold. In the gravels of the San Juan River
the two metals are present in about equal proportions, and in those of
the Atrato the ratio is approximately 85 of gold to 15 of platinum.

The area including the watersheds of the San Juan and Upper Atrato
Rivers is known as the Chocó district. T. Ospina, Director of the
Colombian School of Mines[83], estimates that in the area are 5,000 sq.
miles of gold and platinum deposits, the Mira River forming the southern
boundary of the area. In 1916 he estimated that there were in it
68,000,000 c. yd. of actually profitable gravel, with a reserve of
336,000,000 yd. of possibly profitable ground. Platinum has also been
recovered in much smaller amounts on the Micay River in the Barbacoas
district, near the frontier of Ecuador. The stream beds in which
platinum occurs are those in which Tertiary conglomerates have become
eroded; the river gravels about the areas underlain by that formation
are barren. The conglomerates are composed of rounded boulders of basic
rocks, such as diabase, melaphyre, peridotite and dunite[48] p. 620.

At Novita Vieja, in the centre of the Chocó district, a bed of
conglomerate 6 to 12 ft. thick has been laid bare, over an area 2½ miles
long and ½ mile wide, through the sluicing away of the overlying sands.
It contains 0·5 oz. of gold, and 0·5 oz. of platinum, per ton[84].
According to Castillo, the parent rock is a typical gabbro, pyroxene
predominating over the felspar[85] p. 826.

Platinum has been found in the Chocó district in serpentine rock.
Granite also occurs in the same district, traversed by quartz lodes
containing palladium, iridium, osmium and rhodium.

Colombian crude platinum contains from 80 to 85 per cent. platinum, the
remaining 15 to 20 per cent. consisting chiefly of iridium and osmium.
The sands in which it occurs are described as brown in colour, and
carrying, besides platinum and gold, the heavy minerals chromite,
magnetite and ilmenite [85] p. 384.

In the past, mining operations have been very irregularly carried on, by
primitive methods of working, but dredges are now being employed in
increasing numbers. In 1915 a dredge was operated on the Condoto River,
in the province of Chocó, by the Anglo-Colombian Development Company,
and showed good results. Native methods of working are very simple. The
alluvial gravels derived from dried-up beds of ancient rivers are
hand-washed with the use of the _batea_ or dish. Where the metal occurs
in the bed of a river it is obtained by diving girls, who work down to
the platiniferous gravels, removing the gravel in small dishes, the men
being employed in washing the gravels on the river banks[86]. About 90
per cent. of the total output is recovered by these primitive methods.

A large portion of the industry is in the hands of two companies, one of
which is the South American Gold and Platinum Company, of New York, a
Lewisohn company, which has absorbed the interests of the
above-mentioned Anglo-Colombian Development Company, Ltd., the Gold
Fields American Development Company, Ltd., and Johnson, Matthey & Co.,
Ltd., of London. The second company—the British Platinum and Gold
Corporation, Ltd.—has recently amalgamated with the Paris (Transvaal)
Gold Mines, Ltd., taking in the latter’s interests on the Opogodo and
other places.

The question of transporting platinum concentrate to the coast is not a
matter of much difficulty, as the Atrato River is navigable as far as
Quibdo, and the San Juan can be ascended by vessels of moderate draught
for over 140 miles inland.

An estimate of average working costs appears to be 6_d._ per c. yd. for
dredging, and 3_d._ for hydraulicking[87]. In 1917 new platiniferous
deposits were discovered in the Caceres district, between the Cauca and
Nechi Rivers, in the department of Antioquia. The mineralized area
extends along the Caceri River, a distance of 14¼ miles, the width at
the north end being 1¼ miles, and 300 ft. at the southern extremity [10]
p. 545.


                                ECUADOR

Platinum occurs, in association with the gold obtained from steam
gravels, in the area covered by the Rivers Bogota, Cachabi, Uimbi,
Santiago and Cayapas, but it has not so far been found in sufficient
quantities to be of economic importance.

Dredging has been employed in mining these deposits, but does not appear
to have been a success, and operations are now largely confined to
native washings[88].


                             FRENCH GUIANA

Platiniferous gold-bearing sands are found in the Aporuague River, the
metal, according to an analysis by A. Danmer, having the following
composition in percentages: platinum, 41·96; gold, 18·18; silver, 18·39;
copper, 20·56[89].




                     WORLD MAP OF PLATINUM DEPOSITS


[Illustration:

  MAP SHOWING THE PLATINUM-BEARING DISTRICTS REFERRED TO IN THE TEXT.

  (British Empire and Protectorates shaded.)
]




            REFERENCES TO LITERATURE ON THE PLATINUM METALS


-----

Footnote 1:

  Lindgren, W.: “Platinum and Allied Metals,” _U.S. Geol. Surv., Min.
  Res. of U.S._, 1911.

Footnote 2:

  Thomas and MacAlister: _The Geology of Ore Deposits_, London, 1909.

Footnote 3:

  Gowland, W.: _Metallurgy of Non-Ferrous Metals_, London, 1918.

Footnote 4:

  Dunstan, B.: _Queensland Govt. Min. Journ._, 1917, =18=.

Footnote 5:

  Lindgren, W.: “Platinum and Allied Metals,” _U.S. Geol. Surv., Min.
  Res. of U.S._, 1910.

Footnote 6:

  Rose, T. K.: “Electrolytic Refining of Gold,” _Trans. Inst. Min. and
  Met._, 1914–15, =24=, p. 45.

Footnote 7:

  Hill, Jas. M.: “The Platinum Situation,” _Eng. Min. Journ._, July 26,
  1919.

Footnote 8:

  Hautpick, E. de: _Mining Journ._, Feb. 1, 1913.

Footnote 9:

  _Mineral Industry_, 1916, =25=.

Footnote 10:

  _Mineral Industry_, 1917, =26=.

Footnote 11:

  _Review of Foreign Press, Technical Supplement_, War Office, May 27,
  1919, p. 395.

Footnote 12:

  _Mining Journ._, Dec. 27, 1919.

Footnote 13:

  _Chem. and Met. Eng._, Oct. 15, 1918, p. 607.

Footnote 14:

  Hill, Jas. M.: “Platinum Deposits of the World,” _Eng. Min. Journ._,
  June 30, 1917.

Footnote 15:

  Merz, A. R.: _Journ. Ind. and Eng. Chem._, Nov. 1918, =10=, No. 11.

Footnote 16:

  _Annual Statements of Trade of the United Kingdom._

Footnote 17:

  Spurr, J. E.: “Who Owns the Earth?” _Eng. Min. Journ._, Feb. 7, 1920.

Footnote 18:

  _Records Geol. Surv. of India_, 1916, =47=, pt. 3, p. 163.

Footnote 19:

  _Records Geol. Surv. of India_, 1919, =50=, pt. 3, p. 156.

Footnote 20:

  _Records Geol. Surv. of India_, 1915, =46=, p. 284.

Footnote 21:

  Zealley, A. E. V.: _South Rhod. Geol. Surv., Short Rept._ No. 3, March
  20, 1918.

Footnote 22:

  _Bull. Imp. Inst._, 1907, =5=, p. 137.

Footnote 23:

  “Geology of the Selukwe Mineral Belt,” _Geol. Surv. Bull. South
  Rhod._, 1919, No. 3, p. 65.

Footnote 24:

  Versfield, W.: Rept. on Metal Resources of Union of S. Africa, 1918.

Footnote 25:

  Goodchild, W. H.: _Trans. Inst. Min. and Met._, 1916–17, =26=.

Footnote 26:

  Bettel, W.: _S. African Mines_, Nov. 10, 1916.

Footnote 27:

  Hall, A., and Humphrey, W. A.: “The Chromite Deposits of the Bushveld
  Plutonic Complex,” _Trans. Geol. Soc. S. Africa_, 1908, =11=, pp.
  75–6.

Footnote 28:

  _Mining Journ._, Feb. 29, 1913.

Footnote 29:

  Mackenzie, G. C.: _Can. Min. Inst. Bull._, April 1919.

Footnote 30:

  Camsell, C.: _Mining Journ._, May 1914, p. 523.

Footnote 31:

  Uglow, W. L.: “Geology of Platinum Deposits,” _Eng. Min. Journ._, Aug.
  30, 1919; Sept. 6, 1919.

Footnote 32:

  _Chem. Trade Journ._, 1911, =49=, p. 271.

Footnote 33:

  _Min. Sci. Press_, April 10, 1920, p. 536.

Footnote 34:

  _Board of Trade Journ._, 1917, =99=, p. 156.

Footnote 35:

  _Can. Min. Journ._, 1916, =37=, p. 548.

Footnote 36:

  _Can. Min. Inst. Bull._, 1918, No. 63, p. 99.

Footnote 37:

  _Geol. Surv. of Canada, Min. Res. of Canada_, 1903, No. 818.

Footnote 38:

  _Board of Trade Journ._, April 17, 1919, p. 504.

Footnote 39:

  Howley, G. P.: _Mining World_, 1907, =26=, p. 783.

Footnote 40:

  _N.S.W. Dept. of Mines, Ann. Rept. for 1918_, p. 52.

Footnote 41:

  _N.S.W. Dept. of Mines, Ann. Rept. for 1915_, p. 59.

Footnote 42:

  Hill, Jas. M.: “Platinum and Allied Metals in 1916,” _U.S. Geol.
  Surv._, July 12, 1917.

Footnote 43:

  _Rec. of Geol. Surv. N.S.W._, 1916, =9=, pt. 3, p. 127.

Footnote 44:

  _Min. and Sci. Press_, April 10, 1919.

Footnote 45:

  Bell, G. M.: _Economic Geology_, 1906, =1=, No. 8, p. 749.

Footnote 46:

  _Mineral Industry_, 1914, =23=.

Footnote 47:

  Krusch, P.: “The Platinum Deposits of Germany’s Palæozoic” (trans. by
  F. S. Schmidt), _Min. and Sci. Press_, 1914, =109=, p. 880.

Footnote 48:

  _Pan-American Union_, 1917, =45=.

Footnote 49:

  _Mining Journ._, 1904, =76=, p. 597.

Footnote 50:

  Hill, Jas. M.: “Platinum and Allied Metals in 1917,” _U.S. Geol.
  Surv., Min. Res._, 1917, pt. 1, p. 11.

Footnote 51:

  Vissotzki, N.: _Bull. du Comité géologique_, St. Petersburg, =22=,
  1903 (abstract in _Trans. Inst. M.E._, 1903, =27=, p. 660).

Footnote 52:

  Hill, G. M.: _U.S. Comm. Repts._, 1917, No. 94.

Footnote 53:

  Duparc, L.: _Soc. Ings. Civils, France, Mem. 1916, Bull._ Janv.-Mars.

Footnote 54:

  Ball, S. H., and Low, B.: _Eng. and Min. Journ._, March 10, 1917, p.
  407.

Footnote 55:

  Tovey, L.: _Eng. and Min. Journ._, Oct. 10, 1908, p. 704.

Footnote 56:

  _Chem. Trade Journ._, 1917, =60=, No. 1,562, p. 362.

Footnote 57:

  _Eng. and Min. Journ._, Mar. 6, 1920.

Footnote 58:

  _Mineral Industry_, 1915, =24=, p. 580.

Footnote 59:

  Posewitz, T.: _Geology and Mineral Resources of Borneo_, 1892 (trans.
  by F. H. Hatch).

Footnote 60:

  _Mineral Industry_, 1913, =22=, p. 597.

Footnote 61:

  Hundeshagen, L.: “The Occurrence of Platinum in Wollastonite, Sumatra,
  N.E.I.,” _Trans. Inst. Min. and Met., 1903–4_, =13=, p. 550–2.

Footnote 62:

  Wada, Tsumashire: _Minerals of Japan_, 1904, p. 89 (trans. by Takudgi
  Okawa).

Footnote 63:

  _Bull. Econ. de Madagascar_, 1912, No. 2, p. 86.

Footnote 64:

  Hautpick, E. de: _Min. Journ._, July 27, 1912, =98=, p. 747.

Footnote 65:

  _Mineral Industry_, 1918, =27=, p. 571.

Footnote 66:

  _Eng. and Min. Journ._, Jan. 11, 1919, p. 107.

Footnote 67:

  Mertie, J. B., Jr.: “The Salt Chuck Palladium-Copper Mine,” _Eng. and
  Min. Journ._, July 3, 1920.

Footnote 68:

  Martin, Johnson and Grant: _U.S. Geol. Surv., 1917_, _Bull._ No. 587,
  p. 238.

Footnote 69:

  Campbell, Donald G.: “Palladium in Alaskan Lode Deposits,” _Min. and
  Sci. Press_, Oct. 11, 1919.

Footnote 70:

  _Board of Trade Journ._, Dec. 11, 1919, =103=.

Footnote 71:

  _Min. and Sci. Press_, Mar. 15, 1919, p. 367.

Footnote 72:

  Hall, F. A.: _Eng. and Min. Journ._, Oct. 10, 1914, p. 642.

Footnote 73:

  Knopf, A.: _Min. and Sci. Press_, June 5, 1915, p. 878.

Footnote 74:

  _Chem. and Met. Eng._, March 24, 1920.

Footnote 75:

  _Min. and Sci. Press_, March 9, 1920.

Footnote 76:

  _Eng. and Min. Journ._, May 25, 1905, p. 985.

Footnote 77:

  Taft, H. H.: _Eng. and Min. Journ._, 1918, =106=, No. 21, p. 900.

Footnote 78:

  Hussak, Euginio: “O Palladio e a Platina no Brasil,” _Annas da Escola
  de Minas de Ouro Preto_, 1916, No. 8, 85–188.

Footnote 79:

  Ferraz, Luiz Caetano: _Annas da Escola de Minas de Ouro Preto_, 1909,
  No. 11.

Footnote 80:

  Carneiro, A. J. de Sousa: _Riquezas Mineraes do Estado da Bahia_,
  1908.

Footnote 81:

  Maclaren, J. M.: _Gold: Its Geological Occurrence and Geographical
  Distribution_, London, 1908, p. 25.

Footnote 82:

  _Journ. of the Royal Society of Arts_, 1908, =56=, p. 884.

Footnote 83:

  Ospina, T.: Paper read before second Pan-American Congr., Jan. 3,
  1916.

Footnote 84:

  White, R. W.: _Eng. and Min. Journ._, 1897, =63=, p. 189.

Footnote 85:

  Castillo, J. C.: _Min. and Sci. Press_, 1909, =98=.

Footnote 86:

  “Platinum-seeking in Colombia,” _The Times_, Nov. 26, 1912.

Footnote 87:

  _Mining Journ._, Nov. 30, 1918, p. 700.

Footnote 88:

  Millar and Singewald: _Mineral Deposits of South America_, New York,
  1919, p. 405.

Footnote 89:

  Kunz, George F.: “Platinum and Palladium in Brazil,” _Pan-American
  Bull._, April 1919, p. 408.

Footnote 90:

  _U.S. Comm. Repts._, 1919, No. 21, p. 387.


                               PRINTED BY
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------------------------------------------------------------------------




                          TRANSCRIBER’S NOTES


 1. Footnote [90] (was 64) was unanchored.
 2. P. 59, added missing title “WORLD MAP OF PLATINUM DEPOSITS.”
 3. Silently corrected typographical errors and variations in spelling.
 4. Archaic, non-standard, and uncertain spellings retained as printed.
 5. Footnotes were re-indexed using numbers and collected together at
      the end of the last chapter.
 6. Enclosed italics font in _underscores_.
 7. Enclosed bold font in =equals=.
 8. Subscripts are denoted by an underscore before a series of
      subscripted characters enclosed in curly braces, e.g. H_{2}O.