The biggest factor that contributed to the overall decline in the company's diamond recovery rate was the 16% drop at the Argyle mine in Western Australia. Rio Tinto is the sole owner of the mine, which closed on November 3 last year.

At the same time, the output of the Diavik Mine in Northwest Canada, which Rio Tinto operates in partnership with Dominion Diamond Mines ('Dominion'), fell by 7% to 3.7 million carats.

Rio Tinto and Dominion are in a legal battle throughout 2020. Dominion owns 40% of the Diavik factory and filed for bankruptcy protection in April last year, citing the impact of the COVID-19 pandemic.

In November last year, after successfully preventing Rio Tinto from selling the portion of its recovered diamonds to settle outstanding debts, Dominion appeared to have narrowly avoided bankruptcy by selling its neighboring Ekati mine to a group of creditors.

Its share in the Diavik mine is not included in the transaction, and its future role in the mine is still unknown.

Rio Tinto announced that it expects to produce 3 million to 3.8 million carats of diamonds in Diavik, its only remaining fully operational diamond mine in 2021.

At the same time, Rio Tinto's other Canadian mining partner, Star Diamond Corp ('Star'), announced that the batch sampling results of its Star-Orion South project in Saskatchewan were positive.

More than 3,500 diamonds with a total weight of 210.68 carats were found in the latest sample, including three larger type IIa diamonds. Pink diamonds are always Type IIa, and yellow diamonds have been unearthed at this location before.

Ken MacNeill, President and CEO of Star Diamond Corp, said: "The recent recovery of larger type IIa diamonds from Rio Tinto Canada's bulk sample program continues to strengthen our expectations for the recovery of large, high-value diamonds in future production diamond mines."

Rio Tinto and Star are also involved in an ongoing legal battle, and Star claims that its partners engaged in "malicious predatory behavior" throughout the transaction. The company also opposed Rio Tinto's exercise of early options to acquire 60% of the site. Rio Tinto described these claims as "unfounded."

It also accused Rio Tinto of mismanagement and cost overruns, which Rio Tinto denied.

Star-known as Shore Gold at the time-first began drilling at the site in 1996 and hired Rio Tinto as a partner to develop the site in 2017. Analysts described the site as "very cumbersome due to scale and expense." .

As Mining.com reported in August last year, the Canadian court has ruled that the case can continue, but warned Star that it faces a "hard battle." The date of the trial has not yet been determined.

Read more: After the closure of the pink diamond mine, Argyle Tender broke the record during the pandemic, Rio Tinto announced a new diamond tender; mining partners are on the verge of bankruptcy Rio Tinto is involved in legal disputes between Canadian mining company Rio Tinto and mining partners Facing further legal challenges