Tin
When tin is bent it produces a crackling sound known as the 'tin cry.' A sound caused by the crystals that make up the tin, 'twinning', a feature specific to this kind of mineral.
Humans have traded and used tin for over 5,000 years. One of the first uses man put tin to was in combining it with copper to make bronze. There are artefacts of copper being coated with tin dating back to the first century AD and many samples of tin plated iron exist that can be traced back to the 16th century. Much of the early use of tin can probably be attributed to its relatively low melting point.
Pure tin is a silvery white metal, highly crystalline and malleable. Although tin has many uses, its main use remains tin-plate, this is the practice of coating steel with tin for the packaging of food. The solder used by electricians in joining wires is a tin alloy. Another important use as an alloy is in making bearing (white metal) shells and for metal coatings. Organic compounds of tin are used as fire retardants, pesticides, wood preservatives and plastics. Inorganic compounds, on the other hand, are used in glazing and ceramics. Tin has a high resistance to fatigue and corrosion, readily recyclable and non-toxic.
Primary and Secondary Deposits of Tin Ore
The most important tin ore is known as cassiterite, although tin is also found in sulphide minerals like stannite. The two main ways to locate tin deposits are known as either primary or secondary deposits:
Primary deposits - Underground primary deposits of ore containing tin are often associated with granite intrusive rock formations caused by magma bodies becoming embodied in the rock itself, as against that of volcanic rock that carries minerals on its surface.
Secondary deposits – These are also known as placers and have come about as the result of intense erosion and weathering of the primary deposit on the surface. Cassiterite is resistant to most chemicals, it forms residual concentrations and is quite heavy. Concentrations can be found as a primary deposit known as eluvial but when located on slopes below the deposit they are known as colluvial. If located in a creek or river bed the cassiterite can be carried downstream to finally become embedded as an alluvial placer deposit. Over long periods of time this placer deposit can become buried by lava or sediment, it is then referred to as being a deep lead. Some important tin deposits are found on ocean beds. These have usually been deposited there as a result of a submerged river bed. In fact over 50 percent of the world tin production is found in these types of deposits, particularly in Thailand, Indonesia and Malaysia.
Renison Bell – Australia's Largest Tin Producer
The Renison Bell Tin mine, between Rosebery and Zeehan on the West Coast of Tasmania, one of the largest underground tin mines in the world, contains over 85 percent of Australia's total tin resource. This massive deposit is of a primary carbonate replacement nature. The next biggest tin mine in the country is located at Greenbushes in Western Australia. Tin here is recovered alongside
the mineral tantalum from a primary deposit that has been considerably weathered. Mines that have the potential to grow as future resources are proven include Doradilla, Collingwood and the district surrounding Bynoe harbour.
Smelting of Tin can Take up to 12 Hours
Cassiterite is converted to tin by heating it to a temperature above 1200 degrees Celsius. This is achieved in a reverberatory furnace. Additional tin recovery is achieved by re-smelting the slag left over after recovering tin from the original smelting operation. The smelting process that can take up to 12 hours consists of a furnace charge containing silica fluxes, limestone, a carbon reducing agent and cassiterite. The molten metal is tapped into what is known as a settler from which the resulting slag is allowed to overflow into pots. The molten tin accumulates in the bottom of the settler from where it is retrieved and cast into pigs or slabs for refining.
Australia has around 1.3 percent of the word tin resource which totals seven million tonnes. Asian countries have 27 percent, Malaysia 15 percent, Thailand 12 percent and Indonesia 10 percent. Other countries that have large tin reserves include; Russia, Peru, Bolivia and Brazil.
Australian Mines that produce Bauxite
Gove (NT)
Up to 600 workers employed at the Gove bauxite refinery in the Northern Territory face an uncertain future as Pacific Aluminium suspends alumina production.
Ely (QLD)
The Ely Alcan Queensland Pty Ltd agreement at the Weipa bauxite mine is due to expire in 2041 but an option will give it a further 21 years extension.
Skardon River (QLD)
Gulf Alumina acquired 100 percent of the Skardon River tenement in 2011 from its koalin mining joint partner to develop the mining of bauxite at the site
Weipa (QLD)
The Weipa bauxite mine on the western side of the Cape York Peninsula in northern Queensland is both owned and operated by Rio Tinto Alcan.
Huntly (WA)
The Huntly mine in Western Australia is the largest bauxite mine in the world currently producing about 23 million tonnes of bauxite annually.
Willowdale (WA)
The Willowdale bauxite mine that commenced production in 1984 still processes 10 million tonnes of bauxite a year at the nearby Wagerup Refinery.
Worsley (WA)
The Worsley bauxite mine and alumina refinery in South West Western Australia employs more than 1,800 people and produces 4.6 million tonnes of alumina annually.
South Aurukun (QLD)
The South Aurukun bauxite tenements on the Cape York Peninsula in Far North Queensland are held by Gulf Alumina.
Marchinbar Island (NSW)
The Marchinbar Island bauxite deposit in far north Northern Territory could be mined to satisfy a growing demand from China in the near future.
Kwinana Refinery (WA)
The Kwinana refinery in WA employs around 1,000 direct employees with 60 percent living in the nearby towns of Rockingham, Cockburn and Kwinana.
Wagerup Refinery (WA)
The Alcoa owned Wagerup alumina refinery in W.A. has received governmental approval to lift alumina production from 2.6 to 2.65 million tonnes annually.
Pinjarra Alumina Refinery (WA)
The Pinjarra alumina refinery, near Mandurah south of Perth, is an important part of Alcoa's three refinery system in Western Australia.
Portland Aluminium Smelter (VIC)
The Portland Aluminium smelter in western Victoria, a joint venture operation between Alcoa, CITIC and Marubeni, caters solely to the Asian market.
Felicitas (WA)
The Felicitas bauxite project in Western Australia contains a bauxite resource of 220 million tonnes that will give it a life of mine of 25 years
South Of Embley (QLD)
Despite Rio Tinto placing its South of Embley bauxite project in Cape York, Queensland, on hold for 18 months it still considers it a 'good project.'
Bauxite Hills (QLD)
The Bauxite Hills Project on the Cape York Peninsula in Queensland is hoping to take advantage of an expected increase in the demand for Alumina.
Bald Hill (TAS)
Australian Bauxite Limited's Bald Hill mine, in Tasmania, is to start production in December, 2014. It is the first new bauxite mine in Australia, for over 35 years.
Urquhart Point (QLD)
The Urquhart Point Heavy Mineral Sands Project in Cape York in Far North Queensland is expected to begin production in mid-2015.
Amrun (QLD)
The Amrun bauxite project in far north Queensland, that was previously known as the 'South of Embley' project has been approved for development and expected to be in production by 2019.
