Tin 23K a tonne. Rarer than Nickel at 15K (deeper depths)
Tin (Sn) has been used and traded by man for more than 5000 years, it has been found in the tombs of ancient Egyptians, and was exported to Europe from Cornwall, England, during the Roman period. The principal ore of tin is cassiterite (SnO2) but some tin is produced from sulphide minerals such as stannite (Cu2FeSnS4).
Tin is a silver-white metal of low melting point, is highly ductile and malleable, resistant to corrosion and fatigue, has the ability to alloy with other metals, is non-toxic and is easily recycled. At temperatures below 13°C it can change to an amorphous greyish powder known as grey tin and, because of the resultant mottled appearance of tin objects, the action is commonly called tin disease.
Tin has many important uses throughout the world, particularly as tinplate which is used as a protective coating on steel cans for food packaging. It is used in the production of the common alloys bronze (tin and copper), solder (tin and lead) and type metal (tin, lead and antimony). It is also used as an alloy with titanium in the aerospace industry. Inorganic compounds of tin are used in ceramics and glazes while organic compounds of tin are used in plastics, wood preservatives, pesticides and fire retardants.
The annual world mine production of tin is ~238 000 t (2000), with the major producers being China (41%), Indonesia (20%), Peru (15.5%), Brazil (5.5%), Bolivia (5%) and Australia (3.8%). Australia’s annual mine production is ~9 000 t and 85% of the economic resources are at the Renison Bell deposit in Tasmania which supports one of the world’s largest underground tin mines. Greenbushes in Western Australia is also an important producer of tin along with tantalum. A significant amount of tin is recycled; the steel can recycling rate is 50–60% in the western world.
South Australian deposits South Australia’s tin production is insignificant and totals ~2 t of cassiterite concentrate. The major known tin occurrences are on the Gawler Craton where cassiterite was first recorded in 1899 at South Lake. This occurrence was also prospected ~1917 and in the early 1940s. The workings comprise several shafts, the deepest being 16.5 m. There is no recorded production but cassiterite concentrate, probably <2 t, was produced on site. Mineralisation is in quartz veins, up to 1 m wide, within Archaean Kenella Gneiss of the Mulgathing complex. Mineralisation is considered to be sourced from Mesoproterozoic Hiltaba Suite granite.
Cassiterite was first reported at the Mount Mitchell Tin Workings in 1923 at the northern end of the Glenloth Goldfield. Prospecting comprised pits, trenches and shallow shafts to 7.5 m extending for ~800 m along strike. Cassiterite is disseminated in north–south-trending quartz and greisen veins, up to 3 m wide, hosted by Archaean to Palaeoproterozoic Glenloth Granite. The cassiterite and associated gold, monazite, molybdenite and base-metal sulphides are considered to be derived from a shallow Hiltaba Suite batholith. There is no recorded production from the workings.
At Warna Rock Hole, anomalous but erratic tin values have been recorded from quartz–greisen veins within Hiltaba Suite granite.
Significant cassiterite concentrations were discovered in the Curnamona Province in 1980 at Prospect Hill and subsequent exploration has returned drill intersections of up to 3.5% Sn over 6.2 m. Cassiterite with minor chalcopyrite, sphalerite, scheelite, silver and gold is contained within a siliceous, elongated east–west zone of highly deformed Mesoproterozoic acid volcanics at the northern end of the Mount Babbage Inlier.
TRF Price at posting:
11.0¢ Sentiment: LT Buy Disclosure: Held
