West Musgrave Project, Mantamaru Community, West Musgrave Block, Ngaanyatjarraku Shire, Western Australia, Australiai

Regional Level Types
West Musgrave Project	Project (Research Phase)
Mantamaru Community	Community
West Musgrave Block	- not defined -
Ngaanyatjarraku Shire	Shire
Western Australia	State
Australia	Country

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World-class Ni-Cu-PGE sulphide deposits within the West Musgrave Block (West Musgrave Province); hosted by a gabbronorite intrusion.
Discovered in 2000.

Located approximately 30 kilometres south south-east of Jamieson. Nebo-Babel is a concentrically zoned shallow north north-west plunging tube-like body of gabbronorite intrusion, split and off-set by the Jamieson Fault, separated by one kilometre, and also at different vertical depths. One is called Nebo, the other Babel. They have similar morphologies but are different mineralogically.

Discovered by Western Mining Corporation in 2000, it came under the control of BHP Billiton who took over the company in 2005. It is a major Ni-Cu-PGE discovery of massive and disseminated sulphides, and caused a rush to the area, but subsequent drilling by Western Mining produced more muted results. It is estimated at 392 million tonnes at 0.3% Ni, 0.3% Cu, and 0.18 grams per tonne PGE (2010), with minor cobalt and gold.

Nebo-Babel in total extends 5 kilometres and is 1 x 0.5 kilometres in cross-section.

It is a gabbronorite intrusion, with plagioclase, ortho and clinopyroxene, minor olivine, oxides and apatite. Oxide-apatite rich gabbronorite occurs at the eastern end of Nebo. Mineralization is mainly confined to the upper parts of the intrusion and consists of disseminated magmatic sulphides, and massive sulphide lenses.

The intrusion is overturned. Country rock is granulite facies granitoid gneiss, with K-feldspar, plagioclase, and quartz making up 80% of the rock, the remainder amphibole, biotite, oxides, apatite and trace orthopyroxene, with sulphur absent.

It is believed the deposit was formed from three distinct magma pulses. The initial one formed the marginal units of the intrusion. The next emplaced the core of the intrusion. The largest and final one resulted in a closed system crystal fractionation to show the mineralization today.

The deposit shows well preserved fabrics and textures, and is zoned with a variably textured leuco-gabbronorite outer shell, then mineralised gabbronorite, then barren gabbronorite, and finally oxide-apatite gabbronorite. Ni-Cu-PGE is confined to the first two zones, and occurs as massive sulphide breccias and stringers, and disseminated gabbronorite hosted sulphides.

As of 2020 the deposits were acquired by Oz Minerals.
Ni-Cu-PGE.

The deposit was discovered in 2000, and purchased from BHP in 2014 by Cassini Resources Limited. Nebo-Babel was the largest Ni-Cu prospect discovered in the world at that stage for the prior ten years. It poorly outcrops, in flattish desert covered in spinifex, and is about as remote as it gets in Australia. The major obstacle to mining is the distance to a port.

The deposit is a west south-west plunging flattened tube of gabbronorite intrusive, offset by one kilometre by a fault, breaking the formerly continuous tube into two deposits called Nebo and Babel. The plunge of the tube steepens and swings south-west at the western end of Babel.

It is believed the deposit was formed from three distinct magma pulses. The initial one formed the marginal units of the intrusion. The next emplaced the core of the intrusion. The largest and final one resulted in a closed system crystal fractionation to show the mineralization today. Geochemical variations in the deposit reflect different mantle sources and different degrees of partial melting, rather than outside contamination.

The deposit shows well preserved fabrics and textures, and is zoned with a variably textured leuco-gabbronorite outer shell, then mineralised gabbronorite, then barren gabbronorite, and finally oxide-apatite gabbronorite. The gabbronorite variably contains plagioclase, ortho and clinopyroxene, and minor olivine, oxides and apatite.

Ni-Cu-PGE is confined to the first two zones, and occurs in massive sulphide breccias and stringers, and disseminated gabbronorite hosted sulphides. Massive and breccia sulphides occur as discontinuous lenses close to or along the Hanging Wall contact between the gabbronorite and felsic orthogneiss. Sulphides occur in order of abundance as pyrrhotite, pentlandite, chalcopyrite, with trace bornite and pyrite. Platinum groups minerals occur as tiny irregular grains of moncheite, merenskyite, michenerite, and melonite.

Indicated and Inferred resources by Cassini are 283 Mt, with an estimated 20-25 Kt Ni and 25-30 Kt Cu, with significant cobalt at 30 000 tonnes.

Commodity List

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Mineral List

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18 valid minerals.

Rock Types Recorded

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