Rio Tinto Output More Than Doubles Amid Move to Underground Mining

Rio Tinto’s diamond production spiked in the fourth quarter as the company mined rough from the new underground portion of its deposit.

Total output climbed 43% year on year to 1.1 million carats for the three months that ended December 31, the miner said last week. The company mined from the new underground area of its A21 deposit, which produced more diamonds during the period as Rio Tinto started to ramp up production only in the last quarter of 2024.

Additionally, the company benefited from a strong comparison with the same period a year earlier, when it was still returning to full operations after temporarily shutting the area in July when ground subsidence made operations unsafe.

For the full year, output surged 61% to 4.4 million carats.

Diavik is Rio Tinto’s only remaining diamond mine following the closure of Australia’s Argyle deposit in November 2020. The miner increased its share in Diavik from 60% to full ownership in November 2021, taking control after joint-venture partner Dominion Diamond Mines was unable to meet its portion of maintenance costs. In 2024, Rio Tinto also sold its 75% interest in the Fort à la Corne diamond exploration project in Saskatchewan to joint-venture partner Star Diamond Corporation, as part of a strategy to sharpen its focus on metals and other minerals. The Australia-based miner continues to operate a diamond-exploration program in Angola.

Rio Tinto shelled out $40 million to move into underground mining at the A21 portion of Diavik. That area of the deposit is due to be depleted by the end of the first quarter of this year.

Image: Diavik mine. (Rio Tinto)