The National Union of Mineworkers is due to kick off a strike at Gold Fields’ South Deep operations at 17:00 on Friday afternoon, in an industrial action the company admits will hurt production.

The strike is the union’s latest response to failed consultation with employers over restructuring, which the company says is aimed at increasing productivity and reducing costs for the mine.

NUM says Gold Fields is trying to expand outsourcing in the company to more operations.

In a statement released on Thursday Gold Fields said it would close operations at the South Deep mining operations and apply the "no work, no pay" rule.

NUM South Deep branch secretary Thulani Mashibini told Fin24 on Friday morning that on Friday afternoon, the union, which represents 80% of the company’s workforce, would withdraw its labour from South Deep.

"The strike commences today in the night shift. It begins at five o' clock. We are embarking on a full-blown strike. All members of the NUM will not proceed to work. We are opposing unreasonable retrenchment and the company's failure to consider prevention measures we have proposed," said Mashibini.

Regarding the points of contention between the union and Gold Fields, Mashibini said the company’s new commitment to reducing costs and outsourcing labour was a way of "sidestepping" the newly introduced national minimum wage.

"We outsourced work done by South Deep employees to parties in the communities... [E]ven though these jobs were not up to standard, we fought for contractors to maintain those functions," Mashibini said.

Mashibini said the company had demonstrated no intention to give back or maintain the jobs lost to outsourcing, and instead wanted cheap labour by outsourcing as much work as possible.

"The company has not responded to us at all, but has made media announcements and been informing markets. But the employer is intimidating us with threats of ‘no work no pay’. We are expected to promise peaceful protests when they call riot squads on workers," he said.

Mashibini said the union would hold a mass meeting at 4pm, before the strike will commence.

