ALEXANDER WINNING SOUTH Africa's biggest trade union group, COSATU, has led nationwide protests against job losses, wage curbs and corruption cases, in an outpouring of anger at how workers have been treated during the coronavirus crisis. The union federation organised motorcades, pickets and marches in the country's nine provinces, although it was not clear how many of its more than 1 million members heeded a call to stay away from work. Labour unrest regularly affects companies in sectors like mining during negotiations over wages, but it is much rarer for COSATU, typically an ally of the governing African National Congress…