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.