"The NUM [National Union of Mineworkers] is opposed to any retrenchment irrespective of the numbers involved. The union is highly perturbed by Anglo's decision to bypass the stakeholder meetings scheduled for next week and go ahead with such an announcement," NUM general secretary Frans Baleni said in a statement on Saturday.
"The NUM will do everything within the framework of the law to oppose these retrenchments and is determined to even mobilise for strike to show its disapproval."
Baleni said Anglo American Platinum (Amplats) decided to show its critical stakeholders "the middle finger" which undermined sound industrial relations and labour peace.
NUM said it intended approaching the Commission for Conciliation, Mediation and Arbitration to declare a dispute, and it would strike.
On Friday, Amplats announced that it would cut 6 000 jobs instead of the 14 000 it predicted earlier.
"Anglo American Platinum expects that the revised proposals have the potential to reduce the number of mining and processing jobs affected to approximately 6 000," it said in a statement.
This would be done in line with the Labour Relations Act, and consultations with unions and employee representatives would start in due course, it said.
In January, the company said it would review its business in response to demand for platinum and because of "challenges" which had eroded profitability.
This was in the aftermath of 44 deaths – 34 of them at the hands of the police – near Lonmin Platinum's Marikana operations during a pay strike, and a prolonged industry-wide strike last year.
Of the estimated 14 000 job losses, at least 13 000 would have been in the Rustenburg area.
Earlier in the year, the company said it suspended the Act's section 189 consultations on retrenchments, for negotiations with the department of mineral resources and unions.
At the request of the department, this became a "bilateral engagement" between the company and the department of mineral resources.
The company's other proposals included consolidating Rustenburg operations into three operating mines through the integration and optimisation of Khuseleka Two and Khomanani One and Two mines into the surrounding mines.
Khuseleka One remains operational, which was the principal revision to the previous proposal.
This would result in a reduction of production capacity of approximately 250 000 ounces a year in 2013, and by about 100 000 ounces a year more in the medium term. – Sapa