At its own mines, Glencore said profit was hurt by lower prices for coal and cobalt in particular.

The Storm copper project on Somerset Island, Nunavut, has been the focus of intensive exploration efforts.

"The problem is that, in the gold industry, most of the tier one assets remaining are embedded in bad assets. And you can’t unlock them,” Bristow says.

Data from the US Geological Survey suggests global copper reserves will fall short by 80%, global nickel reserves by 90%, and cobalt by around 96%.

Copper output was hit earlier this year after nationwide protests, but mining conglomerate Grupo Mexico has been upbeat.

The US is 100% reliant on imports for at least 12 key minerals deemed critical by the government.

Data showed China's imports and exports fell much faster than expected in July.

The company also maintained its full-year production outlook for gold and copper.