Mount Pleasant, Black Flag Goldfield, Kalgoorlie-Boulder Shire, Western Australia, Australiai

Regional Level Types
Mount Pleasant	Mountain
Black Flag Goldfield	Ore Field
Kalgoorlie-Boulder Shire	Shire
Western Australia	State
Australia	Country

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14 kilometres south-west of Broad Arrow and 36 kilometres north-west of Kalgoorlie. The deposits run north-south with at least 40 small open pits, covering an area about 5 kilometres long by 1 kilometres wide. Virtually the entire area is a maze of open pits, some underground mines, haulage roads, tailing heaps, processing plants etc, which has cleared all before it. The mines include narrow sinuous pits accessing palaeochannel deposits, more traditional oxide open pits, and some underground mining on primary gold.

Gold was discovered here is 1893 by prospectors Garrity and Clancy (surnames), financed by R.H. Henning. Hundreds of men arrived from Coolgardie to the field, and a town called Black Flag developed. From 1895, large companies were formed which developed open pits and underground workings where the modern mines are now. Several batteries were constructed totalling 120 stamps. For a time across 1896 to 1897, the goldfield was considered the largest in Western Australia, even rivalling the Golden Mile at Kalgoorlie. But the gold was patchy, and bad management saw most mines close by the very early 1900's. The town along with these disappeared.

The field was left to the occasional prospector, until modern exploration showed an interest in the area from the 1980's. Open pits were developed by Consolidated Exploration, and Great Boulder Holdings Ltd (a subsidiary of Western Mining Corporation), with production commencing mid 1987. Consolidated Exploration purchased a 100% interest in the project in July 1987.

In the process Consolidated Exploration racked up a 200 million dollar (Australian) debt by the following year, and sold the leases to Joseph Gutnick's Centaur Mining and Exploration. In the early 1990's they were operating eight pits in the area named after Australian beaches, due to the granite weathered upper ore looking like beach sand. The names never stuck. Astro Mining, National Mine Management and B.H.P Gold had neighbouring leases also that mining was taking place at. Centaur Mining also developed the nearby Cawse nickel mine, which ultimately led to its downfall.

Norton Goldfields Ltd was able to consolidate the leases from Carnegie Gold Pty Ltd, Neil Newman and others around 2013. It has since selectively mined various locations in the area, and the broader region, with ore being transported to its Paddington processing plant south of Broad Arrow.

Regionally,the rock is a succession of tholeiitic and high Mg basalts and sediments intruded by differentiated ultramafic and mafic sills. The Mount Pleasant deposits are on the south-west limb of a gently south-east plunging anticline, with the Liberty Granidorite Pluton (8 x 10 kms) of biotite and hornblende, which has intruded the core of the anticline. The east and west margins of the Liberty Granitoid is differentiated mafic gabbro norite intrusive rocks of the Mount Pleasant and Mount Ellis sills. The northern margin is bounded by ultramafic flows of the Siberia Komatiite.

Quartz veins are common in the granitoid, thought to be the source of the gold in the palaeochannels. Gold in the granitoid is associated with quartz-carbonate veins with coarse pyrite and other sulphides, in sericite, K feldspar and albite altered adamellite. In the Mount Pleaseant Sill gold is associated with pyrite in quartz veins.

Mineralisation is controlled by a north north-east trending structural corridor between the Black Flag and Royal Standard Faults, hosted in predominantly mafic volcanic rocks. Within and adjacent to the structural corridor is an array of variably orientated gold mineralised vein structures.

Commodity List

This is a list of exploitable or exploited mineral commodities recorded from this region.

Mineral List

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

26 valid minerals.

Rock Types Recorded

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