The first underground production from the world's largest diamond mine - Western Australia's massive Argyle project - is now expected to come on stream early, by December 2010.
This is currently 25 weeks ahead of schedule and under-budget, as the mine successfully pushes ahead with its $1.86 billion expansion to take its open-pit output into an historic underground block caving mining operation.
Mine owners are also pushing to bring the maiden underground mining timeframes back even further to a possible six months jump start - to mid-2010.
The update on Argyle's future - which will also include planning from 2011 to take Argyle through to at least 2025 - was detailed today at the first day of the 2008 Paydirt World Diamond Conference in Perth by Argyle Diamonds Underground Project Director, Mr Ed Tota.
"Construction overall is 24 per cent complete and we have expended nearly $670 million of the anticipated $1.8 billion cost," Mr Tota said.
"Work to date includes completion of 20 of the 34 kilometres of tunnels - or about 60% of that total scope of work."
Mr Tota said that in preparation for the underground move, Argyle had commenced a major transition as "we are coming in with a huge highly automated underground mine which will totally replace all current open-pit throughput through the processing plant.
"But we are in a huge rush to get up and running as soon as possible to replace lower grade throughput from the Northern Bowl open pit."
Argyle's underground is being developed around a current 60 million tonne ore reserve, with anticipated annual production of 9.5 million tonnes a year via conveyor lift to surface.
This is expected to produce 20-25 million carats a year for at least seven years - levels equivalent to current open-pit yields.
