"While the company had claimed to be losing over a 1000 ounces per day equivalent to R1 million, they failed to show good cause by living up to workers' demands," the union said in a statement.
Workers have demanded a 15 percent wage increment and a R3500 living out allowance.
The company has offered an 8.0 percent rise and a living out allowance of R1700, up from the current level of R1600.
According to the NUM, the parties would meet on Wednesday at the Commission for Conciliation, Mediation and Arbitration (CCMA) in Polokwane.
"This strike will continue to cause havoc to Northam's financial performance. It is up to them whether they want a resolution or not," said Zwelitsha Tantsi, the NUM 's chief negotiator at Northam.
Northam Platinum could not comment immediately.
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