In an unprecedented move, the National Union of Mineworkers (NUM), Association of Mineworkers and Construction Union (AMCU), UASA and Solidarity will hold a joint press conference in Boksburg tomorrow to "pronounce the way forward" in the pay dispute.

"The four unions are united in their view that Sibanye-Stillwater should accede to workers' demand of an increase of R1500 per year for the next three years," they said.

"Alternatively, Sibanye-Stillwater should benchmark their offer on the recent wage agreement signed with Harmony Gold."

Harmony struck a three-year wage deal earlier this month with five unions - the above four plus the National Union of Metalworkers of South Africa.

The NUM had said earlier this year that for the first time in the history of bargaining in the gold sector, it would be negotiating with companies on an individual basis, outside of the traditional centralised collective bargaining council.

Sibanye-Stillwater's gold operations had been hobbled by a five-month strike to April 2019, when the AMCU agreed to a deal previously signed by the NUM, UASA and Solidarity.

Company spokesman James Wellsted told Bloomberg the labour groups had declared a dispute and talks were now taking place under the auspices of the Commission for Conciliation, Mediation and Arbitration.

The wage increases were unaffordable for Sibanye-Stillwater and "will result in the early closure of the mines if we accede to the unions' demands," he told the wire service.