The Northern Territory has a range of mineral sands resources including zircon, rutile and leucoxene-rich coastal sands on the Tiwi Islands, ilmenite-rich sands overlying weathered dolerite in the Roper region, garnet-rich alluvial sands in the Harts Range region and monazite- and xenotime-rich alluvial sands in central Australia.
The Sill 80 ilmenite project, located 105km east of Mataranka in the Roper region, has a resource of high-quality ilmenite in surficial cover overlying sills of Derim Derim Dolerite that intrude the Roper Group. There is no publicly announced resource for the project, which is operated by Australian Ilmenite Resources Pty Ltd.
Production initially commenced in 2013, and following plant upgrades and recommissioning, the project has increased its production, with more than 37,000 tonnes of ilmenite produced in 2020/21. The project has longer term potential to produce up to 300,000 tonnes of ilmenite concentrate per annum.
Deposits of heavy mineral sands along the northwestern coastline of the NT, the most significant of which are located in Melville and Bathurst islands. Total reserves plus resources estimated at these deposits in 2006 were 13.13 Mt averaging 4.4% heavy minerals, containing 106,000 tonne zircon, 56,000 tonne rutile, 59,000 tonne ilmenite and 34,000 tonne leucoxene. Past mining has occurred at Andranangoo Creek West (2006-2008; 22,487 tonne of concentrate produced), Lethbridge West (2009-2010; 11,500 tonne produced) and Lethbridge South (2011-2013; 33,000 tonne produced). An undeveloped resource occurs at Kilimiraka on the southwestern coastline of Bathurst Island.
Potential also exists in Central Australia for alluvial sand deposits containing monazite and xenotime that represent a potential source of rare earth elements, with a high proportion of heavy rare earths such as dysprosium. The Charley Creek project, 120km west of Alice Springs is the only advanced project, and also has potential to produce zircon, rutile and ilmentite.
Substantial resources of abrasive-quality garnet occur within alluvial sands, watercourses and sand dunes north of the Harts Range, northeast of Alice Springs. The Harts Range garnet sand deposit, located 170km northeast of Alice Springs contains 1.2 Mt of contained garnet with an additional 2.6 Mt garnet in adjacent deposits. Australian Abrasive Minerals Pty Ltd commenced production in 2016, and after intermittent periods of production the project entered care and maintenance in 2019.
In July 2020, TNG announced that it had acquired the Arrakis mineral sands deposit near the South Australian border. Arrakis is hosted in dune sands overlying the Musgrave Province with 10 km of strike extent. The heavy mineral fraction is dominated by a magnetic fraction containing substantial ilmenite, along with minor zircon content.
Care and maintenance
Harts Range garnet – Australian Abrasive Minerals Pty Ltd – 23 Mt @ 5.1% garnet