Mineral Sands

MINERAL SAND MINING IN AUSTRALIA Mineral sand mining in Australia has been, and will be for some time yet a very important part of our economy. Australia is lucky to have some of the largest deposits of heavy metals in the world. Unfortunately there is sometimes a negative attitude toward mineral sand mining and its impact on the environment. However, if managed carefully, such a resource can continue to have huge benefits for our nation. Most Significant Sand Mining Areas in Australia The most significant mining areas in Australia today are mostly along the coast, however, there are several others inland, where ancient seas and rivers have left deposits of mineral sands. Bemax Resources operates the Ginko Mine, which was one of the first mining operations in the Murray Basin, Douglas and Ouyen (in Victoria). Iluka Resources has also recently begun mining operations in the Murray Basin. CRL (Consolidated Rutile Limited) is currently mining mineral sands on Stradbroke Island, and deposits in mid-west WA and south-west WA are being mined by Iluka. How Mineral Sand Deposits Have Formed Mineral sands such as rutile, ilmenite, zircon, monazite and magnetite are derived from igneous rocks, such as basalt and granite. Over millions of years these rocks have been eroded away by wind and water, and washed into the sea. Eventually, the waves wash these particles of heavy minerals onto the beach. Because they are heavier than the silicone component of the sand surrounding them, they stay behind as the waves wash the lighter particles back out to sea. The wind also helps to concentrate the deposit of heavy mineral particles, by blowing the lighter sand particles away. This process occurs while the currents carry the mineral sands to that particular area. After the current changes, and carries the sediment elsewhere, the silicone component of sand and its impurities form another layer on top and bury the heavy mineral layer. Main Minerals Currently Being Harvested The main mineral sands currently being harvested in Australia are rutile, ilmenite, zircon, monazite and magnetite. Each of these minerals has similar properties and exists naturally in sand particles since they have been eroded from the igneous rock from which they were formed, by wind and water (see table 1 below). Table 1 – Chemical Formula & Physical Properties of Harvested Minerals (Minerals Downunder, Magnetite) Mineral

Chemical Formula

Rutile

TiO2

Ilmenite

FeTiO3

Zircon

ZrSiO4

Monazite

(Ce, La, Nd, Th)PO4

Magnetite

Fe3O4

Physical Properties - red-brown - opaque - reflective - black/grey - hard - magnetic - high melting point - hard - many different colours or transparent - melting point of >2500ºC - non-corrosive - radioactive - red-brown - grey/black - metallic - magnetic

© Sarah Don, Australia, 2007

Main Uses of Zircon Zircon is probably the most versatile of all the mineral sands mined in Australia. It varies in colour and opacity, and can even be transparent, or of “gemstone quality” (Minerals Downunder). Zircon scores 7.58 on the hardness scale (diamonds have a hardness of 10), and has a very high melting point of more than 2500ºC, so it is useful as an abrasive and for lining furnaces. It is also commonly used in television and computer screens as well as a glaze for ceramics and as an ingredient in toothpaste. Zircon is also resistant to corrosion, making it a safe material for use with industrial chemical production. Economic Benefits The mineral sand mining industry is a very important part of the Australian economy. Mineral sand mines all over Australia employ thousands of skilled and qualified workers. In more remote areas (such as the Murray Basin), workers are sent out to the mine for several weeks, so the pay is better and the workers receive more time off. The mining of mineral sands along the east coast for forty-seven years, up until 1980, turned over some 5,800,000 tonnes of rutile and 5,600,000 tonnes of zircon valued at $975,000,000. The majority of minerals extracted from Australian beaches and inland deposits are exported to countries such as China for manufacturing. Australia has the world‟s largest supply of rutile and zircon at about 40% for each, and has the second largest share of the world‟s ilmenite (19%) after China (Mineral Sands). In the past 20 years, the exportation of the mineral sands mined in Australia has contributed $500 billion to the Australian economy (Mining & Minerals Overview). Environmental Protection Each mining company has its own policy on the methods used to rehabilitate the areas they mine, and to what extent they nurture the ecosystem until it is self sustainable. The government also sets certain standards, which have become more stringent in recent times, for the level of care that must be taken by mining companies to rehabilitate mined areas. Most companies use similar strategies that involve re-contouring the sand dunes, planting native plants and reintroducing animals to the area. CRL has conducted extensive mining operations on North Stradbroke Island since 1966, and restores an average of 75 hectares of sand dunes and their vegetation every year. Surveys are carried out before the mining process can start, to keep a record of the area‟s state before it is disturbed by the mining machinery. After the mining has finished, the sand is cleaned and the dunes are reconstructed to resemble their original shape as much as possible. Then different species of native plants are sown into the dunes and a fertiliser is applied six to 10 months later. The dunes are sprayed with a biodegradable bitumen called terrolas and windbreaks are strategically placed. Matting is laid to prevent erosion, to help the dunes to keep their shape and to support the vegetation. Log piles, bird perches and nesting boxes are installed to encourage animals to return to the rehabilitated area (Consolidated Rutile Limited). Another method, known as block trans-location, involves the lifting of the top layer of the soil in which the vegetation is growing, and transplanting it to another area. Once the mining operation has finished, the layer of vegetation is transported back to its original place. This is useful for keeping original species of plants that are difficult to propagate. However, some of the fauna species that were driven away may not return (Bemax – Eastern Australia). In some instances where sand mining occurs in coastal areas, it discourages over development, and paves the way for government departments to take control and create nature reserves or list these areas as state forest. If put it into perspective, mineral sand mining does not have an undue impact on the environment. In Australia we burn coal to generate electricity and use plastic to make almost everything we use on a daily basis, and then „dispose‟ of it. So the impact sand mining has on our beaches, fauna and flora is quite minimal compared to what we do to our atmosphere and environment already.

© Sarah Don, Australia, 2007

Bibliography Allenby, G. & Martin, M. (1988) Australia – Environment & People, Science Press, Australia. Bardon, J. (2006) Victorian sand mining moves closer to full production, ABC Western Victoria, Victoria, http://www.abc.net.au/westernvic/stories/s1630536.htm (12/3/07) Bartsch, P. (2001) „Radiation scare at beach estate‟, August 15, from Courier Mail, The (Brisbane). Foster, F.J. (1994) “Australian mineral sands: problems but confidence”, Engineering & Mining Journal, Vol. 96 Issue 4, p26-32. Gibbons, J. (2006) „Cape York‟s ticking time bomb‟, Gold Coast Bulletin, The. Jones, C. (2006) “Cradle of Life”, Cosmos, issue 10, pp.62-65. Morley, I.W. (1982) Black Sands, University of Queensland Press, Queensland. Murphy, S. (2005) Mineral sand mines revitalise drought towns, ABC, Australia, http://www.abc.net.au/landline/content/2005/s1365013.htm (12/3/07) O‟Malley, B. (2002) „Prime seabed targeted for sand mining‟, December 28, from Courier Mail, The (Brisbane). Ryan, S. (2001) „Sand mining demands new bay sites‟, September 19, from Courier Mail, The (Brisbane). Spearritt, P. (2003) Freedom of the Beach, The Brisbane Institute, Queensland, http://www.brisinst.org.au/resources/spearritt_peter_beach.html (14/3/07) Consolidated Rutile Limited, http://www.consrutile.com.au (8/3/07) Bemax – Eastern Australia, http://www.cablesands.com.au/eastern_australia_detail.asp (13/3/07) Magnetite, http://en.wikipedia.org/wiki/Magnetite (17/3/07) Mineral Sands Mining, IBISWorld (13/3/07) Mineral Sands, http://www.australianminesatlas.gov.au/info/aimr/mineral_sands.jsp (18/3/07) Minerals Downunder, http://www.ga.gov.au/education/minerals/TOC.html (8/3/07) Mining & Minerals Overview, http://www.csiro.au/org/ps10.html (17/3/07)

© Sarah Don, Australia, 2007