Mining giant Rio Tinto, the third-largest diamond producer in the world, has put a planned expansion of its Argyle mine in Western Australia on hold due to a risk of flooding, miningweekly.com reports.

In September, the company approved an $803 million project that would convert the mine from an open pit to an underground operation, which is expected to extend the mine's production life through 2019.

A spokeswoman for Rio Tinto said that the company was currently conducting assessments to see whether the water that has accumulated in the mine's open pit after a wet season that saw unusually heavy rains could cause flooding.

However, the spokeswoman noted, while the expansion had been suspended, Argyle's regular diamond production was continuing as normal.

The Argyle mine is the source of 90% of the world's red and pink diamonds.