Johannesburg - The Chamber of Mines was not a bargaining council, Amcu leader Joseph Mathunjwa said on Thursday.
"The chamber of mines is a mouthpiece for the oppressor," he said, referring to mine bosses.
He was speaking outside Impala Platinum's head office in Illovo where hundreds of striking mineworkers had gathered.
Amcu-affiliated mineworkers in the platinum sector have been on strike for over two months, demanding a minimum wage of R12 500 a month for all workers.
They have rejected the companies' offer of a nine percent wage increase.
Mathunjwa earlier told the crowd moves were underway to expand the strike.
"We have filed an application with Nedlac [National Economic Development and Labour Council] in Rosebank," he said.