Magnesium
Magnesium (Mg) is an alkaline earth metal. The eighth most abundant on earth and the fourth most common element behind only iron, oxygen and silicon.
The chemical element magnesium makes up 13 percent of the earth's mass and due to its high solubility in water is the third most common element found dissolved in sea water. The free element, magnesium metal, is not found in a natural state on Earth because of it being so highly reactive. Although once it is made it becomes coated with a thin oxide that masks this reactivity to a fair degree. Free magnesium metal readily burns emitting a brilliant white light which is why it is used in the making of flares.
Magnesium metal is made by the electrolysis of magnesium salts that are found in brine. From a commercial standpoint, the main uses for such a metal being made is so it can be used as an alloying agent when producing magnesium/aluminium alloys which are known as magnalium. These alloys are sought after because of their lightness and relative strength because magnesium is far less dense than aluminium.
Magnesium is also the eleventh most common element, by mass, in the human body. All living cells require magnesium ions to be able to remain living and it plays an important role in manipulating biological polyphosphate compounds such as RNA (ribonucleic acid, which is important in the coding, decoding, expression and regulation of genes), DNA (deoxyribonucleic acid, that encodes genetic instructions of all living organisms and viruses) and ATP (adenosine-5triphosphate, used by cells as a coenzime). This all means the hundreds of enzymes use magnesium ions to allow them to function.
The Uses of Magnesium:
Laxatives contain magnesium compounds
Antacids (milk of magnesia)
Processed as caustic calcined magnesia for use as a food supplement
In the treatment of eclampsia (a life threatening complication in pregnancy)
In agriculture, as the magnesium metallic ion is a centrepiece of chlorophyll and therefore a common additive to fertilizers
A feedstock used as dead burned magnesia and refractory brick use in the lining of furnaces in the iron and steel industry as well as the lining of cement kilns
Use as a filler in paints, plastics and paper
Surface coatings, landscaping, ceramics
Magnesium metal is used in aluminium alloying, casting and wrought iron products,
manufacturing of machinery, tools and mag wheels for cars
Magnesite deposits in Australia are mined by open pit method where the strip ratio ( the amount of magnesite to waste rock) is usually quite high. At the Kunwarara deposit where the strip ratio is relative low owing to a thin overburden of only four metres means that only between five to 10 tonnes of ore has to be mined and beneficiated, to produce one tonne of high grade magnesite.
Once magnesium catches alight it is very hard to extinguish. It is difficult to ignite in bulk form but when powdered, or shaved into thin strips, it is highly flammable. It will keep burning in nitrogen where it forms magnesium nitride, in carbon dioxide where it forms carbon and magnesium oxide and even under water where it forms hydrogen and magnesium oxide. This is why it was used by the military during World War 2 in incendiary weapons. The only practical way of extinguishing magnesium once it begins to burn is to smother it with sand to remove it from the influences of the atmosphere.
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.
