West Musgrave Prospectivity
The West Musgrave Region is highly prospective for intrusion-hosted Ni-Cu-PGE deposits and IOCG deposits for the following reasons:
- It is of Proterozoic age which is a peak time for the development of Ni-Cu-PGE and IOCG deposits worldwide and has a favourable structural setting and source rocks, which include the massive mafic-ultramafic Giles Complex and A-type Tollu Granite.
- The Giles Complex is one of the largest layered mafic-ultramafic intrusive complexes in the world and is related to the continental-scale Warakurna Igneous Province. Large intrusive complexes elsewhere host magmatic Ni-Cu-PGE deposits (i.e. Voisey’s Bay, Canada and Duluth, USA).
- The district has had very little modern exploration. The virtual exclusion from exploration for the 25 year period to the late 1990s (due to the Ngaanyatjarra Land Council restrictions), means that the bulk of the West Musgrave Region has never been subjected to modern exploration techniques, including for much of Redstone’s groundholding.
- The West Musgrave Region is predominately blanketed by thin cover, which hindered explorers in the 1950’s and 60’s due to the lack of appropriate exploration tools at the time. This terrain is amenable to modern geochemical sampling (such as soil/lag geochemistry and Rotary Air Blast (RAB) drilling), which allows exploration for multiple commodities quickly, effectively and inexpensively.
- Supergene processes are demonstrated to have created broad halos of supergene mineralisation, which not only aid exploration targeting but may yield supergene enriched minable deposits.
- The distribution and diversity of known mineral occurrences, including Ni-Cu-(Co)-PGE, Ti, V, Cu-Au (with fluorine, uranium and rare earth elements: ie. potential IOCG), support the applied exploration models and strategies.
Mineral Deposits and Occurrences
There are numerous mineral occurrences in the Musgrave Block. Potential exists for Ni-Cu-PGE-Co deposits, base metals (sediment and volcanic hosted Cu-Pb-Zn-Ag) and various types of gold mineralisation. Major deposits and known mineral occurrences in the district include:
- the Wingellina Nickel-Cobalt Project in the Musgrave region in WA, near the border with South Australia and Northern Territory, a large nickel laterite deposit containing 187Mt @ 1% nickel and 0.08% cobalt. Over 167M tonnes or 90% of this resource is classified as Probable Mining Reserve. This deposit was discovered in the late 1950s by Southwestern Mining Co (Inco) and is currently in feasibility studies. The deposit is associated with limonitic ocherous laterite with gem quality chrysoprase and sits atop an ultramafic intrusive of the Giles Complex.
- the Claude Hills nickel laterite lies 30km east of Wingellina in South Australia and has identified an initial deposit of 33.3 million tonnes at 0.81% Ni and 0.07% Co.
Metals X who hold the Wingellina and Claude Hills Projects consider that the identified resources represent exploration on less than 25% of the known potential mineralised zones in the area.
- the Nebo-Babel project, a major nickel sulphide deposit discovered by WMC in 2000 which included drill intersections of 106.5m @ 2.4% Ni, 2.7% Cu and 0.2g/t PGE, and a resource of about 1 million tonnes contained Ni and 1 million tonnes contained Cu+Co, with an in-ground value of AU$25 billion. Nebo-Babel was discovered using lag sampling and outcropped as scattered gossan, and is therefore principally a geochemical discovery. However, strong magnetic, EM and gravity anomalies highlight the massive and disseminated mineralisation which is hosted within a shallowly WSW-plunging, pipe of gabbronorite intrusive (1078Ma), offset by a fault. The style of deposit is almost identical to the giant Voisey’s Bay Ni deposit in Canada.
- Cassini Resources Limited (ASX: CZI) who acquired the Nebo-Babel project from BHP Billiton in 2014, have been actively exploring in the Musgrave region and on the Nebo-Babel project. The Nebo-Babel Resource is now estimated to be 203Mt @ 0.41% Ni, 0.42% Cu. Cassini have also since identified the Succoth deposit (approximately 13km NW of Nebo-Babel). The Succoth Cu + PGE sulphide deposit has an inferred mineral resource estimate of 156Mt @ 0.6% Cu.
- The Halleys Prospect Cu-PGE mineralisation identified by Redstone Resources is situated on a magmatic flow through zone on the SE flank of the Saturn intrusive complex. Redstone Resources drilling on this prospect resulted in intercepts of up to 74m @ 0.33% Cu and 0.24g/t PGE + Au including 20m @0.56% Cu, 0.32g/t PGE + Au and 0.14% Ni.