Zinc
Zinc is known as ‘The Great Protector’ because beyond being a great sunscreen, it plays a very important role in protecting other metal and steel from rust and corrosion.
Zinc is used as a protective coating for all steel and iron constructions that we take for granted, such as railways, cars, bridges and building frames.
Zinc itself is a shiny metal, blue-tinged white in colour. It has a low melting point, and works well as an alloy with other metals. It is brittle at room temperature, but when heated it is quite malleable and can be formed into wires. It is an effective electrical conductor, and quite hard. Zinc is found in the air, in water and in the biosphere, as well as in rock and soil; all living things contain zinc.
Zinc has never actually been found in its pure form, though there are zinc deposits all over the world. It occurs as an ore, and is found in four kinds of deposits. Volcanic zinc deposits are found with large concentrations of silver, gold and other elements. When it is found in host rocks, these are usually limestone and dolomite rocks, and the zinc is often grouped with lead, copper and silver elements. When it is a sediment deposit, its host rocks are shale, siltstone and sandstone; this kind of ore has a high silver content. The fourth kind of zinc deposit is found in carbonate rocks with calcium and magnesium minerals.
In Europe, zinc was being produced on a large scale by the 1700s. Historians believe that zinc was first used to make brass in the Roman Empire between 20 B.C. and 14 A.D. It took a little longer for Australians to find zinc, however when we did, it played a huge role in the Australian economy. When a large orebody comprised of zinc, lead and silver was found at Broken Hill in 1883, a mine was opened that helped to boost the economy, making zinc a major produce alongside wool and wheat. The mine still operates today, and Australians now use more zinc-coated metals per capita than anywhere else in the world.
In the early decades of zinc mining however, miners didn’t know how to separate zinc from the other materials comprising the ore. Then one day, a mill foreman called James Lyster found a way to separate zinc by crushing the ore, mixing it with water then adding oil and forcing air through the mixture. The zinc stuck to the air bubbles and rose to the top, while the rest sank. This method is called froth floatation, and is still one of the major ways that metals are removed from ore. Once the zinc has been separated, it is heated and chemically treated for purification.
Australia has around 20% of the world’s zinc resources, and produces 1,450,000 metric tons per year (as at February 2012), following China’s production of 3,500,000 tonnes and Peru’s 1,520,000 tonnes. Most of Australia’s zinc mines are found in the Northern Territory and Queensland. The Century Mine in Queensland is Australia’s largest open pit zinc mine, and is expected to become the world’s largest zinc mine when it grows to its full production. It was opened in 1997, and is expected to be exhausted by 2016.
The major use for zinc is as a protection agent for other metals. This is done by coating the steel and metal with molten zinc, a process called galvanising. This is how 60% of Australia’s zinc is used, going into products like poles, wires, household appliances, cars, roofs and steel supports.
The other uses of zinc include making an extremely strong alloy by mixing it with aluminium. This alloy has a very low melting point that means it can be diecast – that is, moulded into different shapes to make a range of finely detailed products such as staples, zips, doorhandles and car parts.
Zinc’s ability to conduct electricity makes it useful in batteries. When zinc is mixed with copper it forms brass, a highly rust-resistant material used on boats, as well as musical instruments, scientific and navigation tools.
People also need zinc in our bodies, as it helps our healing abilities and immune systems. We usually get zinc in meats, nuts, fruits and shellfish.
This metal appears absolutely everywhere in life, including as zinc oxide in rubber tyres, creams, lotions, paints and plastics. As a sulphate it is used to make TV screens, watches and fluorescent lights luminescent. In other compounds, it can stop plastics from cracking, form glues and make wood fire-proof. Interestingly, as it is highly flammable when dry, it is also used in fireworks. Zinc is truly a metal of all trades.
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.
