JOHANNESBURG - "The strike comes after protracted negotiations on medical aid, long service benefits and provident fund amongst others collapsed," the union said.

It was awarded a certificate of non-resolution to allow it to go on strike from April 16, after the matter was taken to the Commission for Conciliation, Mediation and Arbitration.

NUM regional secretary William Mabapa said the union had tried its best to talk to the mine's owners, even after it had been granted the certificate.

He said: "We are convinced the company thought that was a weakness and we have decided to bring them to our level through a massive strike action."

The union wanted disability benefits, Sunday payments to shift supervisors, and separation of workshops.

The strike began on Thursday evening, with 1100 workers taking part.

Foskor is a phosphate mine owned by the Industrial Development Corporation.

Comment from the IDC could not be immediately obtained.