Rio Tinto and Harry Winston Diamond Corp. have decided to make a joint investment of $563 million, above the existing invested funds in the underground mining phase of the Diavik diamond mine. This fund is expected to be spent over two years.%%Involving this additional fund, the total investment in the mine is valued at $787 million. Rio Tinto mentioned that Diavik would be profiled as an all underground mine after its open pit mining work is compete by 2012. Also underground diamond production is scheduled to begin by 2009 and extend beyond 2020.