Kambalda, Coolgardie Shire, Western Australia, Australiai

Regional Level Types
Kambalda	Town
Coolgardie Shire	Shire
Western Australia	State
Australia	Country

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Located about 25 km NNE of Widgiemooltha.

Kambalda is a mining district. The town of Kambalda was first established as a gold mining town in 1897, and remained so until 1966. Nickel was then found here, and the town now revolves primarily around nickel mining.

The town itself is essentially split in two: Kambalda East and Kambalda West.

The deposit was discovered in 1966 and mining commenced in 1967. Owned by Western Mining. In 1986 this deposit was estimated to contain 7% of the western world's nickel reserves. The orebody contains the Lunnon shoot and the Durkin shoot (Durkin shaft).

Nickel was a rare commodity in the 1960s. In the late 1960s to early 70s, massive nickel deposits were discovered in Western Australia. It is known in Western Australian history as the Nickel Boom. Australia holds 35% of the world's reserves, and 90% of this is in Western Australia. Most of the nickel deposits were discovered in the Eastern Goldfields province, particularly centred on the Kambalda region. At present (2012) 22 nickel mines are operational in the Kambalda area. Western Mining Corporation discovered nickel at Kambalda in 1965, and the first mine (Silver Lake Mine) opened in 1966. The Kambalda region produces 35,000 tonnes/year of nickel metal.

Specimens generally come from the 132 North Mine near Widgiemooltha, and the Otter Shoot Mine on the outskirts of the East Kambalda townsite. Nickel secondary species from the Kambalda mines are described by geologists as rare. It needs to be said mining companies often simply describe the lot as nickel ore, which gets processed regardless of the composition.

Geology speaking, the Kambalda Dome nickel mineralisation is one of the most heavily studied in Western Australia. A detailed description is beyond the scope (and my brain power) of this summary.

The Kambalda Dome shows as an elongated feature in a north-northwest direction, located 56 kilometres south-southeast of Kalgoorlie.

From the lowest upwards, is the Lunnon Basalt, overlain by the Kambalda Komatiite which hosts the nickel sulphide mineralisation, Devons Consol Basalt, then a package of slates and greywackes.

The Kambalda Komatiite lays between the two basalt members. Nickel sulphide mineralisation is concentrated at its contact with the Lunnon Basalt, where it occupies the base of the lava flow, in incised channels forming elongated lenses and ribbon-like structures. These trend in a north-northwest direction, up to 3 kilometres long and 300m wide. The channel flows themselves can be up to 100m thick, 500m wide, and 15 kilometres in length. It contains pyrrhotite-pentlandite-pyrite-chalcopyrite, with locally abundant millerite.

The sulphides in the komatiite lava flows are denser, so tend to pool in topographic low areas, enhanced by the thermal erosion of the substrate by the lava.

The ore zone in the Kambalda Komatiite from the base upwards consists of a zone of massive sulphides (95% sulphide) of metasedimentary or melted material and enclaves of olivine. Overlaying this is a zone of matrix sulphide of a jackstraw texture, composed of bladed to acicular metamorphic olivine, spinifex-textured in a matrix of nickel sulphide. Next a zone of net-textured ore, rarely observed, but assumed, as nickel sulphide forming a network textured groundmass liquid in which olivine crystals float in massive sulphide. Described as having the consistency of toothpaste, we are uncertain though if it does much to fight tooth decay. Lastly, a disseminated sulphide zone grading upwards to barren ultramafic in a fine-grained groundmass.

There is a variation in deposits, with some zones missing. While originally formed as generally horizontal volcanic lava flows, processes such as metamorphism, folding etc. create a large degree of variability between the deposits.

The oxidised weathered zone above the ore is dominated by boxworks of goethite, hematite, maghemite and ochre clays. Non-sulphide nickel mineralisation is usually soluble, and preserved as carbonates, or within the ore as nickeline. Mineral species such as gaspéite, hellyerite, otwayite, widgiemoolthalite, and related nickel carbonates have been preserved by the arid environment, but are still rare. Secondary copper species malachite, azurite, chalcocite, and cobalt-nickel compounds are more persistent in the boxworks.

The oxidised zone includes goethite, hematite, limonite, often associated with polydymite and violarite, supergene in origin in the lower portions of the saprolite rock.

Commodity List

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Mineral List

Mineral list contains entries from the region specified including sub-localities

118 valid minerals. 4 (TL) - type locality of valid minerals.

Rock Types Recorded

Rock list contains entries from the region specified including sub-localities