In terms of the Labour Relations Act the union must serve a 48-hour notice to the company of the protected strike action.
The union has declared a dispute against the company’s voluntary separation package and lay-off of 200 workers.
In a statement the union said that it would not relent until the issue had been resolved in its favour.
It believes the current logic and reasoning of the company to be completely and grossly irrational.
The union charges that the company failed to give sufficient notice in contemplation of operational changes that will affect the job security or conditions of employment of any employee.
Numsa is opposed to the retrenchments as it believes they will compound the woes of the metal industry, which is currently losing 2 000 workers a month in the engineering sector.
Xstrata has four chrome mines, four ferrochrome metallurgical complexes and two vanadium operations in South Africa.