Mineworkers in South Africa are gearing up to possibly join public service workers in a five-day-old nationwide strike that has wrought havoc in public schools and hospitals, the main mining union said Tuesday, according to dpa. The National Union of Mineworkers, the biggest trade union in South Africa with over quarter of a million members, said it was mobilising for "huge strike action ... in the absence of a resolution to the current impasse" between the government and public service unions. A mining strike could hamper output of gold and platinum in South Africa, the world's largest producer of the precious metals. Meanwhile Tuesday a phone-in programme on public radio was offering advice on home schooling as pupils were turned away from schools for the third time in a week in parts of the country. And service delivery in many public hospitals continued to be constrained by a shortage of nursing staff although nurses at some hospitals appeared to have heeded a government warning to return to work or be fired. Unions representing over a million public sector workers, including teachers, nurses and police, have vowed to push on with the open-ended strike after rejecting the state's offer Monday of a revised pay increase. The government has offered a 6.5-per-cent pay rise and improved housing and medical benefits. The unions are pressing for a 12-per-cent increase, although some spoke Tuesday in favour of a compromise. Some immigration officers at OR Tambo International Airport in Johannesburg failed to show up for work Tuesday causing some delays in international traffic that had cleared up by the afternoon, radio reports said. Nearly half a million workers downed tools on Friday, the first day of the strike. No new national estimates on participation have been issued by either the unions or state since. The government threatened essential services workers, who are banned from striking, with sacking unless they returned to work Monday but some nurses and teachers say they are too afraid. Reports of intimidation by striking workers against colleagues who defy the strike call have been rife. The principal of a school near Johannesburg was badly beaten Monday, allegedly by other teachers, for choosing to work.