SHANGHAI, June 22 (SMM) - A labour union official said that workers at Chile's state-owned Codelco will begin a nationwide strike on Wednesday to protest the government and the company's decision to close a struggling Ventanas smelter. "We will start from the first shift on Wednesday," Federation of Copper Workers (FTC) president Amador Pantoja said on Monday. Workers have threatened a nationwide strike if the board doesn't invest in upgrading the Ventanas smelter. Codelco said on June 17 it would terminate its Ventanas smelter, which was closed for maintenance and operational adjustments after a recent environmental incident sickened dozens of people in the area.