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 MINERAL SANDS
Mineral sands are emerging as a major mineral resource for Victoria. Mineral sands are ancient beach sands that contain concentrations of
minerals including rutile, ilmenite, zircon and monazite as well as other rare earth elements.
Geology
Rutile, ilmenite and zircon originally grew as crystals in
igneous rocks such as granite, pegmatite and basalt and
some metamorphic rocks. Over millions of years, these rocks
were eroded by the weather, and the minerals were washed
to rivers and streams and in to the sea. These heavy minerals
were then carried back onto the beach by waves, which in
turn drag the lighter minerals such as quartz back into the
sea. The tidal process leaves the heavy minerals on the
beach. Wind further concentrates the heavy minerals as the
lighter quartz sand is blown away more easily.
Over millions of years, this process is constantly repeated and
eventually there large deposits of mineral sands can form on
the beach and along rivers and streams. As the sea levels
and shorelines have changed over geological time most Mineral Sands ore. The dark layers are heavy minerals, the light quartz beach sand.
mineral sand deposits are found in fossilised ancient Source: Wikimedia Commons
shorelines several hundreds of metres to tens of kilometres,
or occasionally even hundreds of kilometres inland from the current coastline. Mineral sands ore bodies essentially fall into two categories based
on the mode of deposition: alluvial (old beach or river systems) or aeolian (sand systems).
Victoria
It is estimated that Victoria’s mineral sand deposits contain eight million tonnes of rutile and six million tonnes of zircon. The Murray Basin, the
current centre for mineral sands activity, holds significant deposits. More than 60 million tonnes of coarse-grained mineral sand deposits and
more than 200 million tonnes of fine-grained deposits have been identified to datei. These deposits are large enough to support several long-life
mining operations which have the potential to bring jobs and investment to the surrounding region.
There are currently mineral sands mining operations at Douglas and Donald in the States west, as well as a minerals separation plant in
Hamilton. Portland is the main port for the exportation of mineral sands mined in the Murray Basin. There have recently been discoveries of rich
zircon deposit in the Gippsland Basin and monazite-rich sands in alluvial deposits near the Bonang and Elphinstone areas.
Use
The spread of mineral sands deposits across Victoria is promising for the future development of mineral sands mining in the State. Demand for
these minerals is increasing with their used in advanced technology products such as computers and smart phones. The development of
Victoria’s rich mineral sands endowment has the potential to bring the jobs and prosperity to Victorian communities across the state.
The principal heavy minerals of commercial interest areii:
•
Rutile (titanium dioxide, TiO2) – a red to black, naturally occurring mineral with a theoretical TiO2 content of 100%, but impurities such
as Fe2O3 and Cr2O2 commonly reduce this to 93–95 per cent. Titanium dioxide is used extensively in the paint industry, where it has
replaced lead carbonate pigments, and as a pigment in plastics, paper and latex rubber. As it is non-toxic it is also used in cosmetics
and pharmaceuticals. About 6 per cent of mined rutile is used to manufacture titanium metal, a light, strong and corrosion-resistant
metal used in the aerospace industry and medical prostheses. Other uses of TiO2 include welding rod coatings, sand blasting and
water filtration.
MINERALS COUNCIL OF AUSTRALIA – VICTORIAN DIVISION
•
Zircon (ZrSiO4) – a colourless to off-white mineral and the main source for zirconium products. Zircon has exceptional refractory
properties, with a melting point of over 2430 ºC. For this reason it is used extensively tasks where resistance to high temperatures in
essential such as foundry work and engine parts. Finely ground zircon is also used in ceramic glazes and specialised ceramics such as
porcelain used in electrical equipment.
•
Ilmenite (FeTiO3) – black and opaque when fresh, but typically undergoes some weathering and iron removal, so that TiO2 contents
are between 45% and 65%. Ilmenite is mined for extraction of titanium dioxide.
•
Monazite (Ce, La, Y, Th)PO4 – a reddish-brown phosphate mineral containing rare-earth metals and is an important source of cerium
and thorium.
Ibid.
Victorian Government, Department of Primary Industries, Mineral Sands fact sheet http://www.dpi.vic.gov.au/earthresources/minerals/industrial-minerals/a-z-of-industrial-minerals/mineral-sands.
i
ii
HP TRIM ID 2013/030669