Rio Tinto has formally approved the development of a fourth pipe, A21, for the Diavik diamond mine; the 60% Rio Tinto-owned joint venture with Dominion Diamond Corp. in subarctic Canada produces gem-quality diamonds.

Alan Davies, Rio Diamonds and Minerals chief executive, said the move “reflects strong confidence in the sector and in our ability to compete effectively;” the mine began production in 2003 and became a fully underground mining operation in 2012. 

Part of the original mine plan, the A21 pipe development is estimated to cost $350 million by 2019. It will provide a key incremental supply for the project 300 km northeast of Yellowknife in Canada’s Northwest, ensuring guidance through 2023.

A21 development will require rock fill dike construction to encircle the ore body located just offshore of existing mining operations at Lac de Gras. Diavik will use the same innovative design and engineering technologies used to construct the Diavik mine’s two other dikes that enabled mining of three existing pipes.