GEOGRAPHICAL DISTRIBUTION
As will be seen from the map, [Plate IX], tin deposits are found in every part of the world, though an inspection of [Table 60] and [figure 9] will show that the deposits within the British Empire are the most important sources of the world supply. Bolivia and the Dutch East Indies have been the chief producers of tin outside of the British Empire, though China and Siam are steadily gaining importance as tin producers.
British Empire.
—The British Empire has tin deposits in England, Asia, Australia, and Africa. The largest production is from the deposits in the Malay Peninsula. The African deposits, those in Nigeria and the South African Union, yield the second largest output of the empire, the Australian deposits rank third, and the Cornwall deposits, formerly the largest producer of tin in the world, now rank fourth.
Malay Peninsula.
—The Federated Malay States and the British Protected Malay States occupy the southern end of the Malay Peninsula. This region, which is entirely British controlled, produced for many years one-half of the world’s output of tin, but in the last few years the output has declined steadily. The decline seems to be due to the exhaustion of the easily worked placer deposits, though in 1917 and 1918 an additional cause was the scarcity of labor.
Plate IX.—Tin-producing localities of the world. By James M. Hill.
Fig. 9.—World production of tin, 1913-1918, in metric tons.
Table 60.—World’s Output of Metallic Tin, 1913-1918, in Metric Tons[142]
(Metal obtainable by smelting from concentrates)
| Country | 1913 | 1914 | 1915 | 1916 | 1917 | 1918 |
|---|---|---|---|---|---|---|
| Cornwall | 5,370 | 5,140 | 5,060 | 4,770 | 4,000 | 4,000 |
| Nigeria | 2,950 | 4,590 | 4,630 | 5,150 | 7,070 | 7,000 |
| Union of South Africa | 2,050 | 2,000 | 2,050 | 1,900 | 1,540 | 1,500 |
| Federated Malay States | 50,930 | 49,820 | 47,520 | 44,570 | 40,470 | 37,970 |
| British Protected Malay States | 1,800 | 2,700 | 4,170 | 4,450 | 4,500 | 4,500 |
| Australia | 8,160 | 5,520 | 5,680 | 5,550 | 4,970 | 4,900 |
| Total British Empire | 71,260 | 69,770 | 69,110 | 66,390 | 62,550 | 59,870 |
| Percentage world total | 52.6 | 54.1 | 53.7 | 52. | 47. | 45.8 |
| Banca | 15,940 | 14,630 | 13,660 | 14,460 | 13,540 | 11,000 |
| Billiton and Singkep | 5,300 | 6,090 | 6,760 | 6,780 | 7,300 | 9,200 |
| Total Dutch | 21,240 | 20,720 | 20,420 | 21,240 | 20,840 | 20,200 |
| Percentage world total | 15.4 | 16.1 | 15.4 | 16.7 | 16. | 15.5 |
| China | 8,390 | 7,120 | 8,000 | 7,630 | 11,800 | 12,000 |
| Siam | 6,660 | 6,740 | 8,520 | 8,960 | 8,600 | 8,600 |
| Bolivia | 26,760 | 22,360 | 21,900 | 21,330 | 28,320 | 28,000 |
| Other countries | 1,400 | 1,500 | 1,500 | 1,700 | 1,800 | 2,000 |
| Total other control | 43,210 | 37,720 | 39,920 | 39,620 | 50,520 | 50,600 |
| Percentage world total | 32. | 29.8 | 30.9 | 31.3 | 38. | 38.7 |
| World total | 135,710 | 128,210 | 129,450 | 127,250 | 133,910 | 130,670 |
[142] Knopf, A., “Tin in 1918,” U. S. Geological Survey, “Mineral Resources of the United States in 1918.”
The largest tin-smelting center of the world is Singapore, where the Straits Trading Co., and the Eastern Smelting Co., both British owned, and a Chinese-owned smelter, have a combined capacity of 58,000 metric tons of metal a year.
A large number of the Malaysian mines are worked by Chinese, though much English and Australian capital is invested in tin mining companies in the Peninsula, and the financial control of the industry is in the hands of British subjects. Political control is exercised by a prohibitive export duty ($285 per ton) on all tin ore exported for treatment except to the Straits Settlements, United Kingdom, or Australia.
As will be seen from [Table 60] the Federated Malay States produce much more tin than the Protected States. Practically all of the tin in the Peninsula is taken from placer deposits, some of which are still worked by hand methods, though part of the black tin is now being mined by dredges.
The backbone of the Malay Peninsula is composed of granite which is intrusive into limestone, shale, and quartzite. Tin has been found in place in practically all of the rock formations. Owing to the intense weathering and erosion of the tin-bearing formations great accumulations of detritus, more or less mixed with clay, all of which carry cassiterite, are found in almost all parts of the Peninsula. The original deposits are so softened by weathering that they can be worked by hydraulic methods.
The provinces of Perak, Selangor, Pahang, and Negri Sembilan, in the Federated Malay States, produce tin. The following table shows their relative importance.
Table 61.—Production of Tin in the Federated Malay States in 1917
| Metric tons | |
|---|---|
| Perak | 25,075 |
| Selangor | 10,595 |
| Pahang | 3,750 |
| Negri Sembilan | 1,055 |
In Negri Sembilan, quartz veins in decomposed pegmatite are worked by hydraulicking and the mixed tin-tungsten concentrate obtained is further separated by magnetic machines. The principal mines are near Titi and Seremban.
Pahang, on the eastern side of the mountains, has many widely scattered tin deposits, both lodes and placers. The chief workings at present are in the mountains near the Selangor boundary, at Bentong, Tras, and Machi. Some mining is also done at various places along the Kuantan River and its tributaries. Transportation is a serious item in working tin mines in Pahang.
Kuala Lumpur is the center of the more important tin-mining operations in Selangor. Both decomposed lode-stuff and gravels are being worked. Near Serendah soft greisenized granite is worked by monitors. Near Tanjong, Malim, and on the Kalumpang and Selangor rivers in the northern part of the state both gravels and decomposed vein materials are worked.
The Kinta district, in the State of Perak, is the most important tin-producing area in the Federated States. A structural valley eroded in soft limestones between granite ridges is the location of most of the workings. The valley is filled with clays and boulder clays carrying tin, and the present stream channels are also stanniferous. Mining is in progress around 15 or more settlements in this district; much of the mining is by open cuts and dredges, but some lode mining is done on pipes in limestones. Next in importance to Kinta is the Larut district, northwest of the former. Placer deposits are the chief source of tin in the district but lodes are worked at Selama and Blanda Mabok. In the south of Perak, at Bruseh, stockworks in schist are worked by hydraulicking, yielding about three-fourths of a pound to the cubic yard of material worked.
Development of the tin deposits in the Protected Malay States has been hampered by transportation difficulties. Until recently the alluvial tin was won by crude native methods. The principal producing comes from the states of Johore, Kedah, Kelantan, Perlis, and Trengganu.
Near Setul, in the State of Perlis, peculiar gravel-filled caves in limestone have been mined for tin. Some of these caves have been followed for four or five miles. In the State of Trengganu, lode mining under European management is under way. The lodes seem to be decomposed stockworks in granite.
An insignificant amount of tin is mined from the beach deposits on the Island of Malacca, Straits Settlements. The tin was derived from schists intruded by granite in which there are many stanniferous veinlets.
Africa.
—As will be seen from [Table 60], the principal production of tin in Africa is from British Nigeria. The district was worked by natives in the early days, but no important production was made until 1904, after the subjugation of the Emir of Bauchi. The production of Nigeria has grown steadily till it reached 8,500 tons of concentrates in 1917. Seemingly all of the mines are controlled by British capital and the exports have been largely to the smelters in England.
The alluvial deposits of Nigeria are in the valleys of the Bauchi Plateau. Soda granite and pegmatites, intrusive into older crystalline rocks, seem to be the source of the cassiterite that has been concentrated by the present streams. Sluicing is the principal mining method, though some deposits are suitable only for dredging. Tin is also known in northern Nigeria in the Ningi and Burra hills, and other localities. In southern Nigeria tin has been found near Akwa-Ibami, in the Uwet district.
The tin output of the Union of South Africa is chiefly from the Waterberg-Zaaiplaats district, in the western Transvaal, a little tin being mined in Swaziland and the Cape province. The production has ranged from 2,950 tons to 3,450 tons of concentrate a year, most of which before the war went to England for smelting, but since 1915 to the Straits Settlements. A small smelter, rated at 250 tons a year, was built at Zaaiplaats in 1917; it is expected to supply the tin needed in South Africa.
The Waterberg district contains several tin fields. Tin ores are found in the Red Granite and Waterberg felsites, sandstones, and conglomerates. In the former the ores occur in pipes, in irregular bodies of altered granite, disseminated in the granite, in impregnations along fissures, and in pegmatites and quartz veins. In the Waterberg series the tin ores are in lodes, and in irregular lenses and pockets whose position is determined by fissures or bedding planes.
In the Potgietersrust district the principal mines are largely pipe deposits in the Red Granite. These pipes, which are very erratic in direction, range from a few inches to 20 feet in diameter; some have been followed for 3,000 feet. The filling material varies greatly, ranging from slightly altered granite to a greenish homogeneous rock; the outer zones are tourmaline-quartz rock. In the smaller pipes the cassiterite is fairly evenly distributed but in the larger pipes it occurs near the outer edges.
In the Nylstroom district the principal mines are working ore deposits in felsites and shales of the Lower Waterberg series. The deposits are brecciated country rock cemented by quartz, tourmaline, cassiterite, and fluorite.
The Warmbaths field includes several mines located along the junction of the Red Granite and the felsites. Tin is found in lodes in both types of rocks and some alluvial tin has been mined. In the Rooiberg field, the tin deposits are practically all in fissures in quartzite intruded by Red Granite. Tin occurs in the Red Granite 40 miles north of Pretoria.
In the Cape Province, near Kuils River, cassiterite is found disseminated in granite and in veins at the contact of granite and slates. Most of the small amount of tin won has been obtained from gravels derived from these deposits.
In northwestern Swaziland alluvial deposits have been worked for a number of years, producing around 500 tons of concentrates a year. At Forbes Reef, schists and slates have been intruded by granite and tin lodes are found near the contact of the two formations.
Tin has been reported in placer deposits in the Winnebah district and in pegmatite dikes in the Mankofa and Mount Mankwadi districts of the Gold Coast. Tin has been found in placer concentrates from streams in Nyasaland. Tin deposits seemingly of little value have been found in the Enterprise district, east of Salisbury, and in the Ndanga district, east of Victoria, in Rhodesia. These deposits are stanniferous pegmatites which are found in schists near granite.
Australia.
—Tin is produced in the following provinces of Australia: Tasmania, Queensland, New South Wales, West Australia, Northern Territory, Victoria, named in the order of their importance. In 1907, the output of Tasmania was about 14,000 tons of concentrates, but production since then steadily declined until it became nearly stationary at 3,000 tons annually for the last few years, and it is believed that this output can be maintained for some time.
There are tin-smelting works at Launceston, in Tasmania; Woolwich, near Sydney, New South Wales; and Irvinebank, near Herberton, Queensland, capable of producing over 4,200 tons of metallic tin a year. Of recent years tin concentrate is being sent to the Straits Settlements (Singapore) for smelting. The exports of metallic tin from Australian ports in 1917 came to about 3,100 tons.
Practically all of the mining companies are controlled by Australian and English capital, and as the tin is smelted either locally or at Singapore the total Australian output can be considered as under the direct political and commercial control of England.
The total production of tin ore from Tasmania[143] from 1880 to 1918, inclusive, is stated to be approximately 128,200 tons.
[143] Tasmania, Report Secretary for Mines for the year ending December 31, 1918, p. 46.
The most important tin mine is Mount Bischoff, 45 miles southwest of Emu Bay. The deposits, discovered in 1871, are credited with a total production of about 75,000 tons of tin ore. There are several deposits, soft altered quartz porphyries intrusive into schists. Topaz and cassiterite are disseminated in the porphyries, and veins carrying tin and wolframite, together with pyrite and arsenopyrite, are found both in the porphyry and schists.
The Shepherd and Murphy mine, near Middlesex, is in a zone of metamorphism at the contact of granite, intrusive into sandstone and quartzite. Tin, tungsten, and bismuth are produced from this ore. Placer tin deposits on the Ringarooma River (Derby district) supply about 1,000 tons of tin concentrates a year. The principal placer mines are the Pioneer and Briseis. Near Gladstone, placers and lode deposits carrying tin and tungsten are worked. At the Anchor mine, in the Blue Tier district, a tin-bearing granite averaging one-half per cent. tin is worked, but mining has not been profitable. The Renison Bell, Dreadnought-Boulder and Montana mines, in the North Dundas field, are in slates cut by dikes of quartz porphyry. Zinc, lead, and iron sulphides are important in the lodes. In the Heemskirt district, southwestern Tasmania, the tin deposits are in granite and in overlying slate and sandstone. At the Federation mine the ore is in a pipe measuring 25 by 15 feet at the surface, but contracting to only 1 by 5 feet at 115 feet down.
Tin was first produced in Queensland in 1872, and the total output, including 1917, is estimated to be about 144,008 tons. The chief producing districts are Herberton, Cooktown, Chillagoe, near the port of Cairns; Stannhills, Kangaroo Hills, and Stanthorpe, the latter being near the New South Wales border. In the Herberton-Cooktown districts the tin occurs in greisenized granite intruded into slates, schists, and quartzite; bismuth and tungsten minerals are associated with it. Placer deposits are worked by hydraulicking, and in places the tin-bearing greisen is broken down by hydraulic giants. In the Stannhills field, near Croydon, cassiterite is found in veins in granite with galena, sphalerite, and chalcopyrite. The Kangaroo Hills, 100 miles south of Herberton, produces both lode and placer tin. In the Stanthorpe district most of the output is from placer deposits, some of which are buried under basalts.
Tin was first mined in New South Wales in 1872, and the total production, including the output of 1917, is estimated at 84,230 tons of tin and 34,510 tons of tin concentrates.
The chief producing districts are the Vegetable Creek and Emmaville-Tingha-Inverell region, in the northeast near the Queensland border, and the Ardlethan district, 40 miles west of Temora, in the south. In the Emmaville-Inverell region the erosion of stanniferous greisenized granite, intrusive into slates, has resulted in a widespread distribution of tin placers, both in the present streams and in what are believed to be Tertiary stream beds that are now capped by lavas. The Vegetable Creek mines, near Emmaville, are typical of the older placer deposits. Since 1900, dredging has become important, and it is estimated that the dredge production up to 1917 was 18,854 tons of concentrates. Lode mining, although not as important, has been done in this district in pipes and stock works in granite; the typical fluorine-bearing gangue minerals are common, and tungsten, bismuth, copper, and lead minerals are found.
Tin was discovered in the Ardlethan district in 1912 in lodes in granite and schist. Molybdenum, bismuth, and tungsten are commonly associated with tin in the greisenized granite lodes. The Barrier district, in the western part of the province, has not been a large contributor, because of lack of water. Cassiterite is found in dikes of coarsely crystalline granite intrusive into greisen and mica schist.
In West Australia the most important tin-producing districts are Greenbushes, near the southwest, and Pilbara, on the northwest, though there has been a very small recovery of tin in the Murchison goldfield, and Coolgardie. In the Greenbushes district cassiterite is found in pegmatite and quartz-tourmaline veins in granite, but the tin won is from stream deposits and from laterite. In the Pilbara field the alluvial tin has been derived from pegmatite dikes that cut granite and metamorphic rocks.
The production of tin in Northern Territory has amounted to about 200 tons a year, most of it being obtained from pegmatitic deposits in granite in the vicinity of Burrundie.
A few tons of tin concentrates are saved each year in the operation of gold placers in the Northeastern and Gippsland divisions of Victoria.
India.
—The principal output of tin in India is from the Mergui and Tavoy districts, southern Lower Burma; Tharton and Amherst districts, northern Lower Burma; and the Southern Shan States. The production amounts to about 150 tons of metallic tin a year, and is sent to the Straits Settlements for smelting.
In the Mergui district cassiterite is found in alluvial deposits near granite hills, the granite being intrusive into sedimentary rocks of uncertain age. Tin ore is also found in pegmatite and quartz veins. In the Tavoy district tin is obtained as a by-product of wolfram mining. The deposits occur in pegmatite and quartz veins cutting granite and sedimentary rocks. In the Tharton district the tin-bearing alluvium is said to be rich and its development is awaited with interest. Production of tin began in 1912 from the deposits of Bawlake State, Karenni, Southern Shan States, and in 1917 these deposits were the chief producers in India.
Cornwall.
—In the extreme southwest of England is the famous Cornwall tin region, which includes the Camborne, St. Austell, and Liskeard districts, in Cornwall, and the Tavistock district, in Devon. The mines have produced about 8,000 tons of concentrates a year, but at present the output seems to be diminishing; in 1915 the production of metallic tin was approximately 5,000 tons, but in 1918 was only about 4,000 tons.
Tin mining in Cornwall dates back to prehistoric times. In the sixteenth century the mines produced about 700 tons of tin a year; the maximum output was reached in the period 1860 to 1890, when about 10,000 tons was produced annually. It is estimated that the total output of tin from this district is approximately 1,750,000 tons. The mining companies are without exception controlled by British capital.
The second largest tin-smelting capacity in the world is in the Cornwall district. The following companies, Williams Harvey & Co., Penpoll, Cornish Tin Smelting Co., Copper Pass, Redruth Tin Smelting Co., and the London Smelting Co. operate smelters having a combined output of approximately 31,100 tons of tin a year.
The tin deposits of Cornwall and Devon lie about five masses of granite, which are intruded into slates (killas) and greenstones. Quartz porphyry dikes are closely connected with the granite, and the tin lodes are found in both slates and granite, being particularly abundant near intrusive contacts with low dips. The principal lodes are wide zones of fissured rock that are tourmalinized, the less important fissures containing tin and gangue minerals. Copper and tungsten minerals are produced from these lodes, and arsenic is an important by-product of smelting. The lodes in slates are as a rule richer in copper than in the granite, and in depth the lodes contain a larger proportion of tin than nearer the surface. The mines about the Camborne granite mass yield about 85 per cent. of the tin mined, those about the Lands End granite mass 12 per cent., and the mines about St. Austell, Bodmin Moor, and Dartmoor about 1 per cent. each.
Practically all of the tin produced in recent years has been from lodes, but placer tin was mined near St. Austell. The lodes have been worked to a depth of 3,000 feet, which seems to be about the greatest depth to which commercially profitable ore extends. As considerable ground above this level remains to be developed, the district should be productive for some time.
Other Nations.
—Outside of the British Empire the principal tin deposits of the world are in Bolivia, the Dutch East Indies, China, and Siam, named in the order of their importance as producers in 1918. There are small outputs of tin from deposits in Japan, Spain, Portugal, and the United States, and tin deposits are known in Germany, Italy, Russia, Belgian-Congo, and Southwest Africa.
Bolivia.
—Practically all of the tin ore shipped from Bolivia is mined from lodes. Mining began late in the last century. Exports are in the form of barilla, a tin concentrate carrying 60 to 65 per cent. and averaging about 62 per cent. tin. The output has been steadily increasing, and since 1913 Bolivia has been the second largest producer of tin in the world. (See [Table 60], and [Figure 9]). The majority of the companies working in Bolivia are controlled by Chilean or local capital, though a little English, French, Swiss, and German capital was invested in Bolivian tin mines before the war. Recently English and American capital has become interested in the deposits.
Prior to the war practically all of the barilla was sent to Germany and England to be smelted, but lately exports have been to the United States and England. A small Chilean-owned smelter, estimated capacity 900 tons a year, has recently been built at Arica to handle the concentrates from one of the larger mines.
There are four important tin-producing districts in east central Bolivia, in the provinces of Potosi, Oruro, and La Paz. The region lies on the high plateau (elevation, 12,000 feet) and the principal mines are near or in the mountains on the east of the pampa rather than in the western range of the Cordillera. Schists, slates, and quartzites have been intruded by acid igneous rocks, and the tin deposits are found in the granites, the quartz porphyries, and the sedimentary rocks near the contacts. The quartz veins are strong and carry between 3 and 8 per cent. tin in most of the productive mines, though some bodies of ore have carried as much as 40 per cent. tin. Some of the mines were worked for silver by the Spanish, but the silver ores seem to be limited to the upper zones, the lodes becoming relatively richer in tin at depth. Wolframite and bismuth are won as by-products at some of the mines. Pyrite, sphalerite, chalcopyrite, and galena are usually abundant in the tin ores, and tourmaline and fluorite are not uncommon.
The Bolivian deposits are of considerable future importance. Many mines and prospects, either through lack of knowledge or finances, have not been developed; the local management of most of the mines has been notoriously poor; and it is thought that with proper technical direction the output of tin can be greatly increased.
Dutch East Indies.
—On the islands of Banca, Billiton, and Singkep, south of the Malay Peninsula, are important tin mines. As will be seen from [Table 60] the output of tin from these islands has been approximately 21,000 tons a year. Mining began on Banka about 1718, but the Billiton deposits were not worked until about 1860. The mines of Banka are worked by the government, but on Billiton and Singkep the deposits are leased by private concerns, mostly Dutch. At Banka the Dutch government operates smelters having a yearly capacity of 16,000 tons. The concentrates produced on Billiton and Singkep are in part sent to the Straits Settlements for treatment, but some are smelted locally.
Practically all of the tin mined in the Dutch East Indies is from placer deposits, some of which are alluvial. There is, however, a little lode mining on Billiton. The cassiterite was formed in greisenized granite and sediments, and the original deposits are similar to those of the Malay Peninsula. A little tungsten and gold are obtained as by-products of the tin mining.
China.
—Tin deposits in the Mengtze district, near Kochiu, Province of Yunnan, southeastern China, have been worked for many years. During recent years about 8,000 tons of tin have been exported, and it is known that considerable tin ore produced from these deposits is smelted locally, the metal being consumed in China. The exports go out through the French port of Haifong. The mining industry is entirely under Chinese control. Most of the tin ore is obtained by placer and open-cut methods from decomposed granitic and pegmatitic lodes which are found near the contact of granite that is intrusive into limestone. There are less important tin deposits in the Fuchuan and Tungchwan districts, the former producing a very pure metal.
The tin concentrates exported go mostly to Hong Kong and the Straits Settlements for treatment, so the Chinese tin output is more or less at the disposal of England.
Siam.
—In that part of Siam lying in the Malay Peninsula, tin deposits, similar in origin and occurrence to those in the British provinces, are being worked, and as shown by [Table 60] are yearly becoming larger factors in the world’s output. The largest operations are near Renong and Tongkah, where dredging by British companies is active. The chief producing companies are Tongkah Harbor Tin Dredging Co., Tin Benbong, Bangnon Valley, Ronpibon Extended, Beebook Dredging Co., and Katoo Syndicate.
Japan.
—The tin-producing localities in Japan are near Kagoshima, Satsuma, on Kyushu Island; about 50 miles north of Kobe in Tajima province; and near Nayegi, Mino Province, near the center of the main island. Placer deposits near Nayegi have yielded some tin, seemingly derived from pegmatite dikes in granite. The Akinobe mine, in Tajima Province, was developed as a copper mine, but about 1912 tin and tungsten minerals were found in the ore. The veins are in slates and quartzites intruded by diorites. It is said that in 1917 about 40 tons of mixed tin-tungsten ores was produced daily. A small smelter at Ikuno handles the tin concentrates and produces about 250 tons of tin a year. The Susuijama mine, in Satsuma, produces tin from veins, in shales and sandstones, that also carry lead and zinc. Apparently the output is smelted and used locally.
Spain.
—In the provinces of Salamanca, Zamora, Orense, Pontevedra, and Coruña, northwest Spain, there are tin deposits. Lode deposits are found near the contact of granite intrusive into schists and gneisses, and placer deposits have been worked since ancient times. In 1913 about 6,700 tons of ore is said to have been produced, but since then the output has been around 100 tons a year.
Portugal.
—In Portugal, just south of the Spanish border, tin lodes in granite and slates have been found and placer deposits worked in the gravels adjacent to the lodes. The yearly output of these deposits is around 300 tons. It is reported that American capital is interested in some of the Portuguese tin and tungsten deposits.
United States.
—In the United States the domestic output is only nominal, being equivalent to 60 to 100 tons of tin a year. The productive deposits, placers worked by dredges, are in the York district of Seward Peninsula, Alaska. They occur near the contact of granite intrusive into limestones, in peculiar rocks of contact metamorphic origin.
Cassiterite has been mined from gravels derived from pegmatite dikes intrusive in pre-Cambrian rocks of the Black Hills near Tinton and Hill City, South Dakota, and various attempts have been made to mine the lode deposits. These deposits are of more scientific interest than commercial importance. A little stream tin has also been mined on the North Carolina-South Carolina boundary near King’s Mountain, the cassiterite being an original constituent of pegmatite dikes intrusive into pre-Cambrian schists. At Irish Creek, Rockbridge County, Virginia, there are known stanniferous veins in coarse granites. In the Franklin Mountains 14 miles north of El Paso, Texas, quartz veins in granite carrying cassiterite were worked at one time but have not been productive of late. In the Temescal Mountains, Riverside County, California, small quartz veins carrying cassiterite are found in acid granitic rocks that are intrusive into metamorphosed sediments. Considerable work was done in this locality in the years 1880 to 1890, but the irregularity of the deposits and their low tin content do not hold much promise for future production.
Prior to the war the United States, although the largest consumer of tin in the world, produced practically no tin ore, and imported only metallic tin, having no smelters for treating tin ore. Since 1916 smelters have been erected by the American Smelting & Refining Co., and the Williams Harvey Corporation, their estimated capacity being 18,000 tons of tin a year. Presumably these smelters must rely largely on Bolivian concentrates.
Germany-Austria.
—Germany has produced practically no tin ores in recent years, though the country had a smelting industry, estimated at about 16,000 tons of tin a year, dependent on foreign ores. The normal imports of tin ore before the war were 17,000 to 18,000 metric tons a year, most of which came from Bolivia.
In the Erzgebirge, on the German-Austrian frontier, in the Altenberg-Zinnwald district, there was formerly some tin mining. The deposits, which are typical greisen lying near the tops and sides of bodies of granite intrusive into schists and gneisses, have made almost no production for several years and they are considered to be exhausted.
Italy.
—At Campiglia Marittima, Tuscany, iron and tin have been produced from veins in limestone and shale. The output is variable and cannot be relied upon.
Russia.
—In the former Empire of Russia tin has been found in the Trans-Baikal Province, Siberia, and in the Urals and Finland in European Russia. The Siberian deposits are placers in the basin of the Onon River. A German company was formed before the war to work lode tin deposits near Olovianoy, southwest of Nerchinsk, in the Urals. The Finnish deposits are at Pitkaranta, north of Lake Ladoga. The ores are a mixture of magnetite, cassiterite, and chalcopyrite, occurring in altered limestone and schist.
Belgian Congo (Katanga).
—Alluvial tin derived from veins in granite and intruded sedimentary rocks has been found along Lualaba River and on Busanga Ridge. There are no records of production, but the field holds considerable promise.
Southwest Africa.
—Cassiterite occurs in pegmatite, intrusive into granite, in the Erongo Mountains east of Brandberg, and some placer tin deposits have been worked. On the whole the region does not seem to be particularly promising.