[5] The Argyle diamond mine is located in the Kimberley region in the far northeast of the Australian state of Western Australia.

Because it is 185 km (115 mi) by road from the nearest settlement (Kununurra), a complete residential camp was constructed on site.

Small quantities of alluvially deposited diamonds have been known in Australia since the late 19th century, first found by prospectors searching for gold.

Following the discovery of several alluvial diamonds in the West Kimberley region along the Lennard River (Ellendale area) in 1969 a systematic search of Western Australia for the source of these diamonds was begun by a consortium of mining companies, collectively known as the Kalumburu Joint Venture.

[8] In 1979, Muggeridge discovered diamond samples in the floodplain of a small creek that flowed in Lake Argyle.

[citation needed] Over the following three years, the deposit was assessed for economic viability, and in 1983 the decision was made to commence mining operations.

The diatreme pipe formed by explosive eruption of the lamproite magma through a zone of weakness in the continental crust.

Argyle was the fourth-largest diamond-producing mine in the world by volume, averaging annual production of 8 million carats (1,600 kg).

Argyle's open pit mine produced over 750 million carats (150,000 kg) of rough diamonds.

In contrast, the company has no problems selling diamonds in pink, purple and red tones, which are very rare and in high demand, therefore commanding premium prices.

(Author Janine Roberts contends that the "near-gem quality" rating is subjective and misleading because these diamonds can be cut into gems if desired.

[10]) The remaining 95% are about evenly split between classifications of "near-gem quality" and industrial grade; 80% of Argyle diamonds are brown, followed by 16% yellow, 2% white, 2% grey, and less than 1% pink and green.

Argyle diamonds tend to fluoresce blue or dull green under ultraviolet light, and blue-white under X-ray radiation.

As of 2001, reserves and resources in the open-pit-mined area contain 220 million tonnes of 2.5- to 3.0-carat-per-tonne (500 to 600 mg) graded ore, sufficient to sustain current production rates until 2007.

In the late 1990s, part of the west wall of the open pit mine, containing 25 million tonnes of waste rock, began to collapse.

A more conservative view on future production performance and grades could bring forward the economic shut-off criteria.

In 2005, Rio Tinto was given the go-ahead to a future expansion project, moving it from an open pit to an underground mine.

Following an announcement in 2018 that it was no longer economically viable,[23] the mine stopped production on 3 November 2020 after producing approximately 865 million carats with remaining ores processed for the next six months followed by a decade of restoration in conjunction with the traditional owners of the lands.