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.