Copper in London surged to the highest in almost four years after China ordered its top producer to halt output to combat winter pollution, fueling a rally this year driven by optimism about demand and supply disruptions at mines.
The Trump administration, invoking powers the U.S. hasn’t used in more than a quarter century, began a probe into Chinese aluminum imports that could lead to tariffs.
Any restriction on imports of the key metals would likely fall on friendly U.S. trading partners, rather than on China, the ostensible target of the administration's concern about steel and aluminum imports.
Iron ore retreated to the lowest level in at least six years as a rout in China's stock markets threatened to hurt demand just as the biggest producers plan to raise output.
