Argyle Diamond Mine - Production

Production

The Argyle diamond mine leads the world in volume production of diamond, averaging annual production of 35 million carats (7,000 kg), or about one third of global production of natural diamonds. Production peaked in 1994, when 42 million carats (8,400 kg) were produced. Of this quantity only 5% is considered gem-quality, with the rest being either near-gem quality or industrial grade; this is somewhat below world averages of about 20% of mined diamonds qualifying as gem-grade. (Author Janine Roberts contends that the "near-gem" quality rating is subjective and misleading because these diamonds can be cut into gems if desired.) Since operations began in 1983, Argyle's open pit mine has produced over 750,000,000 carats (150,000 kg) of rough diamonds.

Most of Argyle's gem quality production is in brown diamonds. These diamonds are usually difficult to sell, although Rio Tinto has seen some success in a decade-long marketing campaign to promote brown diamonds as champagne and cognac toned. 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. The pink diamonds are processed and sold as polished diamonds by a specialised team based in Perth to customers world wide.

The mine has ore processing and diamond sorting facilities on site. Once diamonds are removed from the ore and acid washed, they are sorted and shipped to Perth for further sorting and sale. A significant quantity of diamonds are cut in India, where low costs of labor allow small diamonds to be cut for a profit; this is especially relevant to the Argyle mine, which on average produces smaller rough diamonds than other mines do.