In 2005, Rio Tinto was given the go-ahead to a future expansion project, moving it from an open pit to an underground mine.
This plan was postponed; in September 2010 Rio Tinto announced fresh plans to develop an underground mine beneath the existing pit, increasing annual production to 9 million tonnes of ore.

The project is predominantly an underground construction requiring high-quality development and engineering excellence.
The Block Cave is expected to operate until the end of 2020 using the latest in mining technology, including Sandvik's auto mining technology.
The project is due to be completed by 2013, two years later than first planned, after diamond prices slumped.
In 2005, Rio Tinto was given the go-ahead to a future expansion project, moving it from an open pit to an underground mine. This plan was postponed; in September 2010 Rio Tinto announced fresh plans to develop an underground mine beneath the existing pit, increasing annual production to 9 million tonnes of ore.
The project is predominantly an underground construction requiring high-quality development and engineering excellence. The Block Cave is expected to operate until the end of 2020 using the latest in mining technology, including Sandvik's auto mining technology. The project is due to be completed by 2013, two years later than first planned, after diamond prices slumped.
Argyle diamond mine