Trump's Commerce Department imposed the Section 232 metals tariffs -- 25% on steel and 10% on aluminum -- in March 2018.

Boston Metal is developing a method to replace coking coal in the steelmaking process with electricity, reducing emissions.

Copper has been wrapped into a larger reflationary trade which leaves it exposed to broader market turbulence such as a sell-off in global equity markets.

The Canadian miner said the spinout would allow for its assets to be properly valued.

U.S. Global Investors traces 10 years of commodity price performance.

LAPFF, whose member schemes manage more than 300 billion pounds in assets, has direct holdings in both Rio and BHP.