The Northern Territory (NT) has a number of substantial critical minerals projects, with potential near-term production of lithium, rare earths, vanadium, titanium, tungsten and molybdenum, and defined resources of cobalt, nickel and magnesium.
The largest known cobalt resource in the NT is at the Browns project near Batchelor in the Pine Creek Orogen, where cobalt occurs with copper, nickel and lead. Sediment-hosted cobalt-nickel-copper mineralisation occurs in the McArthur Basin, and cobalt also occurs within polymetallic copper-bearing mineralisation in the Warramunga and Aileron Provinces.
The NT is an emerging lithium producer, with pegmatite-hosted lithium resources defined at Core Lithium’s Finniss project, in the Bynoe pegmatite field close to Darwin. Core Lithium have completed the environmental assessment process and a Definitive Feasibility Study and are planning production of 175,000 tpa of spodumene concentrate from Finniss commencing in 2020.
Greenfields exploration potential for lithium also occurs in the Aileron Province in central Australia associated historic tin and tantalum mining fields.
Other companies with lithium exploration projects include:
A number of high-grade magnesite (magnesium carbonate) deposits occur near Batchelor in the Pine Creek Orogen, close to infrastructure and Darwin Port. They occur as stratabound bodies within the Celia and Coomalie Dolostones and include the Winchester and Huandot deposits. These have potential for direct shipping of magnesite rock, or export of dead burned magnesia or caustic calcined magnesia.
The Territory’s most significant rare earths deposit is at Nolans Bore in the Aileron Province, 135km northwest of Alice Springs, owned by Arafura Resources Ltd, which is rich in magnet-feed rare earths, particularly NdPr. The most abundant rare earth-bearing minerals at Nolans Bore are fluorapatite, allanite and monazite. The company has most approvals in place and has completed a Definitive Feasibility Study, which includes on-site processing to produce 4,360 tonnes per annum of neodymium and praseodymium (NdPr) oxide and 600 tpa of a mixed middle-heavy rare earth (SEG/HRE) carbonate.
The Aileron and Irindina provinces have high exploration potential for rare earths. Potential also exists for alluvial deposits of rare earths containing monazite and xenotime, including at the Charley Creek project, 120km west of Alice Springs, which has a large alluvial resource.
The Tanami Region also has high potential for rare earths given the existence of vein-hosted xenotime resources at Northern Minerals’ Browns Range project in adjacent regions of WA.
The Territory is prospective but under-explored for nickel. The only defined resources are 59,550 tonne of nickel included in the polymetallic Browns resource in the Pine Creek Orogen, and a small resource at Northern Cobalt’s Stanton Co-Cu-Ni prospect (see Cobalt).
There is considerable potential for nickel sulfide deposits in the Aileron and Irindina provinces where a number of nickel sulfide prospects occur, and numerous generations of mafic and ultramafic intrusions are considered fertile for nickel mineralisation and remain effectively unexplored. Feeders to the widespread flood basalts of the Kalkarindji Province are also a prospective exploration target.
The NT has several tungsten fields and has historically produced 6043 tonne of tungsten concentrate. The largest known resource is at Molyhil, 250km northeast of Alice Springs. Molyhil is hosted in a scheelite-molybdenite-magnetite skarn within the Aileron Province.
Thor Mining PLC have completed a Definitive Feasibility Study at Molyhil and are exploring additional tungsten prospects in the nearby Bonya Hills. Thor Mining PLC have also announced two maiden resources for Samarkand and White Violet deposits.
Further tungsten occurrences occur in the Hatches Creek and Wauchope tungsten fields in the Davenport Province that produced most historic production of wolframite and scheelite.
The NT has large vanadium resources associated with mafic-hosted vanadium-rich magnetite in the Aileron Province in Central Australia. TNG Ltd’s Mount Peake deposit near Barrow Creek is an advanced project with most approvals in place.
TNG have announced plans to produce high quality V2O5, TiO2 and Fe2O3 from a processing plant in Darwin. A similar style of mineralisation occurs at the Jervois vanadium prospect, northeast of Alice Springs.
A second style of vanadium mineralisation is associated with sandstone-hosted uranium deposits, also in Central Australia, including the Bigrlyi deposit in the Ngalia Basin.
Vanadium resources in the NT
Mount Peake – TNG Ltd 160 Mt @ 0.28% V2O5, 5.3% TiO2 and 23.0% Fe