Rio Tinto's Last Diamond Mine Closes

By Rhiannon Hoyle

Rio Tinto said it has dug the last diamond at its Diavik mine in Canada's Northwest Territories, marking the end of its decades-old diamonds business as the giant miner sharpens its focus on commodities including copper and iron ore.

The world's second-biggest miner by market value said it reached final production at Diavik after producing more than 150 million carats of rough diamonds over 23 years of operations. It has now dug up all the diamonds it can profitably mine there.

The final stones will be polished and sold through 2026 and beyond, Rio Tinto said.

The end of mining at Diavik, roughly 185 miles northeast of Yellowknife, comes five years after the shuttering of Rio Tinto's Argyle mine in Western Australia, where it first began producing diamonds in 1983. That operation had also run out of profitable reserves.

Under Chief Executive Simon Trott, who took over the top job at Rio Tinto in August, the company is sharpening its focus on its iron ore, copper, and aluminum and lithium businesses. Like several other big miners globally, it has put copper at the heart of its growth plans, betting more will be needed to meet rising demand for clean-energy technologies.

Rio Tinto said it has long been planning for the end of diamond mining at Diavik--which will take until 2029 to close, followed by a period of post-closure monitoring.

The operation, in which American jeweler Harry Winston previously held a stake, produced mostly white gems--and a small number of rare, yellow ones--recovered from deep beneath a frozen lake.

"Forty years ago there were very few people who believed there were diamonds in Canada--even fewer could have foreseen how the Diavik story would unfold," said Sophie Bergeron, the head of Rio Tinto's diamonds business.

"To arrive at this milestone has required vision, courage and determination to overcome significant challenges to mine diamonds beneath a frozen lake in one of the world's most remote and pristine ecosystems," Bergeron said.

Write to Rhiannon Hoyle at rhiannon.hoyle@wsj.com

(END) Dow Jones Newswires

March 25, 2026 23:04 ET (03:04 GMT)