Geological Survey of New South Wales

Rob Barnes, Chief Geoscientist — rob.barnes@industry.nsw.gov.au | Peter Downes, Senior Geologist — peter.downes@industry.nsw.gov.au

Nickel exploration opportunitiesin New South Wales, Australia

0 200 km2008_10_0292

NORTH

REFERENCE

Ultramafic and mafic rocks

Potential for ultramaficand mafic rocks

OccurrenceDeposit

Nickel

Broken Hill

Doradilla

Nyngan

Homeville

Syerston

Thuddungra

Bungonia

Sydney

A.C.T.

Port Macquarie

Mt Arrowsmith

Volcanics

Jindalee GroupCoolacSerpentinite Belt

Glenelg/Stavely Zoneequivalents

Loch Lily-Kars Block

Great Serpentinite Belt

South

Pac

ific O

cean

types of depositsin nsw

Lateritic nickel depositsProlonged weathering of various ultramafic rocks has resulted in extensive nickel–cobalt-enriched laterites, some with scandium. Known deposits are associated with Alaskan-type intrusive complexes in the central Lachlan Orogen and serpentinite belts associated with crustal-scale fault systems.

Hydrothermally enriched nickel sulfide deposits Nickel can be mobilised when fractionated granites intrude (ultra)mafic rocks, and re-deposited in structural and stratigraphic traps as nickel sulfides. These deposits are also known as Avebury-type after the Avebury nickel deposit (12 Mt @ 1.11% Ni) in Tasmania.

Orthomagmatic nickel sulfide depositsNSW has potential for orthomagmatic Ni-sulfide deposits which form where large volumes of mantle-derived mafic magma intrude continental crust. Deposits can form in a range of geological settings including continental and backarc rifts or along crustal penetrating faults. Large ultramafic bodies have been recognised in central and western NSW and many lie beneath shallow cover.

New South Wales (NSW), Australia, has a range of opportunities for the discovery and development of nickel and associated metals. Deposit types recognised in NSW include:

• Residual nickel–cobalt laterites (e.g. Thuddungra and Syerston)

• Hydrothermally-enriched nickel sulfide deposits (e.g. Doradilla)

• Orthomagmatic nickel sulfide deposits in layered mafic and

ultramafic bodies (e.g. Mt Arrowsmith)

Significant resources of lateritic nickel have been identified and await development. Opportunities for the discovery and development of nickel in NSW arise from:

• The recognition of previously untested deposit styles• Changing economics and technologies of mineral processing, especially for lateritic deposits• Prospective rock sequences being hidden by shallow cover• Lack of exploration effort focused on nickel

Summary

www.industry.nsw.gov.au/minerals

Rob Barnes, Chief Geoscientist — rob.barnes@industry.nsw.gov.au | Peter Downes, Senior Geologist — peter.downes@industry.nsw.gov.au

projecthighlights

Thuddungra Exploration has identified four nickel–cobalt laterite deposits at Thuddungra 300 km west of Sydney. The deposits have a combined resource totalling 168 Mt @ 0.72% Ni and 0.07% Co with significant scandium. Included within this resource are higher grade zones totalling 58 Mt @ 0.99% Ni and 0.07% Co (0.8% Ni cutoff). The nickel–cobalt laterites at Thuddungra formed as a result of weathering of serpentinite during the Tertiary.

SyerstonThe Syerston nickel–cobalt laterite project, 380 km west-northwest of Sydney, contains 76.8 Mt @ 0.73% Ni and 0.13% Co. Significant platinum mineralisation is also present. Nickel–cobalt is developed over the Tout Intrusive Complex, a zoned Alaskan-type ultramafic complex with a serpentinised dunite core surrounded by pyroxenite, gabbro and locally diorite. Nickel–cobalt bearing laterite is best developed over the dunite core. In this area the weathering profile averages 35 m in thickness. Laterite overlying the pyroxenite is thinner, and has elevated cobalt but has relatively low nickel grades.

explorationtargets

Lateritic targets• Nickel–cobalt laterite is associated with Alaskan-type intrusive complexes in the central Lachlan

Orogen. At Homeville, a resource totalling 12.2 Mt at 0.91% Ni and 0.06% Co has recently been identified.

• Residual manganese–cobalt-rich wads hosted by Tertiary coarse-grained manganiferous ‘grits’ occur at Bungonia, 160 km southwest of Sydney.

• Laterite is developed over deeply weathered serpentinite. Potential targets include the Jindalee Group and the Coolac Serpentinite Belt and Great Serpentinite Belt. Nickel–cobalt laterite has been identified near Port Macquarie associated with the Great Serpentinite Belt.

Hydrothermally remobilised nickel sulfide targets• Targets occur where fractionated granites have intruded serpentinites and Alaskan-type

ultramafic complexes in both the New England and Lachlan orogens.• Recent drilling at Doradilla intersected wide low-grade nickel mineralisation in serpentinite with

zones up to 57 m @ 0.4% Ni.• Potential for Avebury-type mineralisation in the Delamerian Orogen can be extrapolated into

southwestern NSW from the Stavely and Glenelg zones in Victoria.

Orthomagmatic sulfide targets• In the Delamerian Orogen, orthomagmatic nickel sulfides have been identified in the Mount

Arrowsmith Volcanics, northwest of Broken Hill. Best reported grades include 0.5% Ni with 0.45% Cu in peridotite.

• A number of large layered mafic–ultramafic bodies have been identified under cover southeast of Broken Hill.

Nickel exploration opportunities in New South Wales, Australia

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www.industry.nsw.gov.au/minerals