Workers said they wanted to cancel their membership to send a clear message that it could not claim any victory or role in their strike, which has been going on since September 12.
On Wednesday, workers were prevented from entering the mine by the police, who turned them away for not having a permit for gathering. Earlier in the day, NUM spokesperson Lesiba Seshoka was quoted as saying. "We don't know what the demand is now. Miners cannot cancel their membership when they have been dismissed because they are unemployed."
Last week, Amplats announced that it was firing about 12 000 workers for participating in the strike, a move some workers regard as nothing more than mere intimidation.
"More than 45 000 of us went on strike but only 12 000 workers are being fired," said strike committee member Evans Ramokga. "You just receive a message and it says you can go and appeal and we went to the shaft and we heard the appeals are not being done there. It seems like it's their favourites that are being given the opportunity to appeal. We've been saying to management: "Book a stadium and talk to your employees. Instead they are sending SMSes. Some of the workers can't even understand English."
The plan to march on the NUM's offices was hatched on Tuesday with workers holding meetings in several shafts and collecting money for taxi fare.
Although they had made it clear they were not marching but merely going to resign en masse, police declared it an illegal gathering and workers returned to the taxi ranks for transport back to Amplats.
The move by Amplats workers points to the continued downward slide of the union, which the tragic strike by Lonmin workers in Marikana seemed to exacerbate. The current wave of strikes, which first swept the platinum sector before moving on to other industries, has been helmed by independent striking committees that have pushed for wage demands outside of established bargaining agreements.
An Amplats strike committee member only identified as "Buccaneer", said their message to the NUM was clear, that "workers would finish what they started without union interference".
Following a violent strike at Implats earlier this year, the Association of Mineworkers and Construction Union (Amcu) announced in June that it had eaten into roughly 75% of NUM's membership at the mine, a fact which was disputed by NUM pending a verification process. Prior to the Lonmin strike, the NUM lost at least 5 000 workers to Amcu, after rehired NUM members did not rejoin the union.
Earlier this month, Implats sent a letter to NUM explaining that its membership at Implats now stood at 13%, giving the union three months to regain lost membership.
Seshoka called the letter a violation of a verification agreement reached in July, saying it would land Amplats in "even bigger trouble".
Following the thwarted mission to NUM's offices, workers told the Mail & Guardian they were going back to shafts to stake out workers that were going to work as they considered the strike to be continuing and the threats of dismissal toothless.
Violence, though not at the levels reached by the Marikana conflict has also been a feature at Amplats, with a worker allegedly being killed by police a few days ago after allegedly intimidating workers. Several businesses adjoining the hostels around the mining complexes were gutted and a burnt car still stood at the entrance of the Entabeni hostel. Workers said its owner had attempted to go to work.