Russian aluminum giant United Co. Rusal plans to invest $200 million in a Kentucky rolling mill that would be the largest new aluminum plant built in the U.S. in nearly four decades.

The plant, which startup Braidy Industries Inc. plans to open next year in Ashland, Ky., is the largest project being pursued in the domestic aluminum industry under the Trump administration’s 10% duty on imports of the metal, imposed a year ago. It would also draw more imports into the U.S. because the mill would roll aluminum slabs from abroad into thin sheets for the auto industry.