Bardoc, Broad Arrow Goldfield, Kalgoorlie-Boulder Shire, Western Australia, Australiai

Regional Level Types
Bardoc	- not defined -
Broad Arrow Goldfield	Ore Field
Kalgoorlie-Boulder Shire	Shire
Western Australia	State
Australia	Country

Latitude: -30.36548
Longitude: 121.2995
MGA Zone 51: Northing 6639489 - Easting 336582.
Descriptive: 8 km north of Broad Arrow in the shire of Kalgoorlie-Boulder, Western Australia.
References: MINEDEX Database 2004 and Halcyon Group open file company reports 2004.

Bardoc refers to the general area of gold mineralisation directly north of Broad Arrow covering a length of 25 kilometres. The former gold processing plant in the late 1980's was also called Bardoc, and geology-wise the area is called the Bardoc Tectonic Zone.

Mining occurred from the late 1890's to early 1900's mainly from the Zoroastrian underground mine producing 56 690 oz of gold from high grade quartz veins to a depth of 120 metres. Aberfoyle Gold Pty Ltd mined Excelsior and Zoroastrian from 1987-1991 with 200 000 tonnes of ore at 2.47 g/t gold from Zoroastrian, and over two million tonnes of ore at 1.5 g/t and 113 000 oz of gold from Excelsior. The Bank of England historic workings cover a strike length of 2 kilometres along the eastern margins of the zone. South Duke was mined by the Broad Arrow Joint Venture in 1986. Leilani was mined by Placer Dome in 2003.

The Bardoc Tectonic Zone consists of variably deformed Archaean succession of mafic-ultramafic volcanic rocks, felsic volcano-sedimentary rocks, felsic intermediate porphyry intrusions, and differentiated mafic-ultramafic intrusions. The sequence has been squeezed between two large granitoids during a regional east north-east to west south-west shortening, and as a result forms a narrow synclinorium bounded by granite rocks of the Goongarrie-Mount Pleasant Anticline to the west, and the Scotia-Kanowna Anticline to the east. There are five major north north-west shear zones which host the gold mineralisation, and multiple cross-structures which influence the concentration of gold. Further the area sits at the intersection of the Bardoc Tectonic Zone and the Black Flag Fault which further influences the distribution of gold. The overall effect is a latticework of structures across the area hosting gold mineralisation.

The richest deposits are Zoroastrian and Excelsior located in the central part of the 25 kilometre strike zone. Excelsior forms a broad 20 to 50 metre wide mineralised zone within the Excelsior Shear, hosted by a sequence of ultramafic and sedimentary schists, deformed by tight upright folding, and subsequent left (sinistral) shearing. Zoroastrian is 300 metres west of Excelsior, with gold mineralisation in quartz veins within and adjacent to the Zoroastrian Dolerite. The gold may also be associated with sulphides in stockwork veins , with the sulphides predominantly arsenopyrite, and minor pyrite and arsenic minerals.

Big Blow South is within the Big Blow Chert Trend, where south plunging high grade gold mineralisation is within porphyry units, intruded on the contact between the Big Blow Chert and underlying ultramafics.

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