(FORTUNE Magazine) – Impala Platinum Holdings Ltd. of South Africa, the world's second-largest producer of platinum, summarily fired 23,000 striking black workers at four mines in Bophuthatswana, about 100 miles northwest of Johannesburg. Only 7,000 workers kept their jobs. South Africa produces about 80% of the platinum used in the non-Communist world. Impala accounts for about 40% of South Africa's estimated annual production of 2.35 million ounces. The striking miners walked out New Year's Day demanding higher wages, better working conditions, and the right to organize their own union. The vast majority are migrant workers, living in all-male barracks near the mines and earning an average of about $100 a month. Gary Maude, Impala's acting chief executive, claimed that with unemployment at record levels, the company could easily find new workers. He is probably right. An employment bureau operated by South African mine owners has 400,000 job applications on file. Maude predicted that the mines would be back in production in two weeks. Still, the shutdown raised new fears about the flow of precious metals from the troubled country. Word of the dismissals sent prices soaring in an already bullish futures market. On the New York Mercantile Exchange, contracts for April platinum deliveries jumped $13.60 an ounce in heavy trading, to $363.20.