Some 500 Zambian mine workers have been sacked after rioting and attacking a Chinese manager...seven union officials have also been arrested. The Chinese manager at the Chambishi copper smelter in northern Zambia was admitted to hospital...The protest [started when]...workers feared...delay [in] negotiations to improve their conditions of service...Chinese investment in mining and manufacturing has not been without controversy - with constant industrial disputes amidst allegations of poor working conditions.