The Association of Mineworkers and Construction Union, the largest labor group at Impala Platinum Holdings Ltd.’s South African operations, said it will go on strike at the world’s biggest platinum mine.

Workers voted in favor of the stoppage at a meeting the union held yesterday with members near Rustenburg, in North West province, AMCU Treasurer Jimmy Gama said by phone. Impala accounts for about 25 percent of global platinum supplies.