Rio Tinto Ltd./Plc. said on 8 th, December 2005 it will proceed with the development of an underground expansion at its Argyle diamond mine in Australia, the world's largest, at a cost of $760 million rather than close the site.

An additional $150 million will be spent on open pit mining, the company said.

India 's diamond cutting and polishing sector and the affordable fashion jewellery industry would particularly benefit from the expansion, the company said.

India 's diamond polishing industry is centred on the Gujarat region, which cuts 11 of every 12 of the world's diamonds.

Analysts estimate that the global value of rough, or uncut diamond production rose over $1 billion to some $10.2 billion last year.

Each year about 45 percent of the Argyle mine's diamonds are classified as near-gem quality, with 50 percent classed as industrial quality diamonds to be used, for example, as an additive in road pavement.

The remaining 5 percent is made up of gem quality diamonds, including the rare and highly valued pink diamonds, as well as the range of sparkling champagne and rich cognac diamonds.