Bow River Mine, Lake Argyle area, Wyndham-East Kimberley Shire, Western Australia, Australiai

Regional Level Types
Bow River Mine	Mine (Inactive)
Lake Argyle area	Area
Wyndham-East Kimberley Shire	Shire
Western Australia	State
Australia	Country

Located 20 kilometres north-east of the Argyle Diamond Mine on the lower reaches of Limestone Creek. The deposit was discovered in the early 1980's by Gem Exploration and Minerals. Mining commenced in 1988 by Poseidon/Freeport, and later Normandy when they took over Freeport. The mine closed in 1995. Astro Mining NL purchased the tenements and infrastructure in 1998.

While the deposit is smaller than the Argyle Diamond Mine, the diamonds found were on average twice the size of those at Argyle. Colours found range from brown, yellow, white, colourless and a few rare pink diamonds.

The deposit is diamondiferous gravels immediately north of Limestone Creek forming part of a low-lying alluvial plain of sand, silt, gravel and black soil. Five diamondiferous gravel horizons were identified, with mining concentrated on the T1 and T2 horizons. T1 contained an estimated resource of 1434 mt @ 0.524 carats per tonne, while T2 was 9945 mt @ 0.383 carats per tonne. Seven million carats of diamond was produced through the life of the mine from 24 million tonnes of gravel.

The T1 gravel horizon is ferruginous, 0.04 to 1.1 metres thick. The terrace is 8 metres above the flood plain, moderately well sorted, deeply oxidised, with sub-rounded pebbles, cobbles and boulders with diamonds through the profile. T2 is 4 metres above the flood plain, ferruginous, 6 kilometres long by 1 kilometre wide and covered in 2 metres of soil and clay. T3 is 2 metres above the flood plain and is a channel deposit. T4 is a flood plain deposit north and south of the creek, well bedded and un-weathered. T5 is the modern channel gravels within the bed of the creek.

Argyle rough diamonds are commonly seen for sale as specimens, as Rio Tinto came to an agreement with De Beers that it could sell a small percentage of its diamonds independently. At Bow River all the diamonds were sold directly to Antwerp dealers, and are not seen for sale generally as specimens.

References

External Links

Other Regions, Features and Areas containing this locality