The Gundlach ratio, which measures the relationship between copper and gold, is trading near the lowest levels since the start of 2021.

Silver Lake had raised the cash component of the proposal by A$44 million after St Barbara rejected its earlier offer of A$707 million.

Polymetal's Russian operations accounted for around two-thirds of the group's revenue in 2022.

The country's gold industry, its largest revenue earner, has collapsed due to a spiraling month-old conflict in the North African nation.

Newcrest was fined A$15,000 in August last year for failing to effectively mitigate dust pollution at Cadia.

Polyus and Polymetal were targeted, according to a statement Friday.

While geopolitical risk in South America is growing, Ecuador, Colombia and Peru remain mineral-rich hot spots with excellent potential for new discoveries.

The parties have voiced growing confidence about striking a debt-ceiling deal.