The U.S. Department of Commerce plans to impose duties on imports of ferroalloy from an Australian plant once owned by the world's biggest miner, BHP Billiton Ltd , according to a preliminary decision released on Friday.

West Virginia-based Felman Production LLC has said large and increasing volumes of silicomanganese, an alloy additive used to make steel, from Tasmanian Electro Metallurgical Co (TEMCO) have "significantly undercut" U.S. prices.

BHP spun off the plant into a separate company, called South32, to shareholders in May.

Commerce set preliminary duties of 11.93 percent on the goods. Its final decision is due in December. The U.S International Trade Commission must also rule on the duties before they can take effect. (sources:Reuters)

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