"The situation at the mine is normal, people came above ground yesterday evening," Amplats spokesperson Mpumi Sithole said.
The industrial action followed the dismissal of four union shop stewards for "inappropriate behaviour".
According to the company about 2400 mineworkers were being prevented from exiting the shaft on Friday.
"We confirm that this is as a result of the suspension of four shop stewards for inappropriate behaviour which is against our behavioural procedure," Sithole said at the time.
Earlier, French news agency Agence France-Presse (AFP) reported that the workers were staging a sit-in strike over the suspension of four union leaders.
"They don't want to come out from underground because they want their leadership's suspension lifted," Association of Mineworkers and Construction Union (Amcu) official George Tyobeka was quoted as saying.
The four Amcu leaders suspended were reportedly accused of submitting fraudulent membership applications in an attempt to inflate union membership numbers.
Amcu and its rival union, the National Union of Mineworkers (NUM), have been struggling for dominance at the mines, which has resulted in violent strikes and assassinations.
Last year, the police shot dead 34 miners at Lonmin's neighbouring mine in Marikana.
Eight NUM members were recently suspended at Lonmin for alleged union membership fraud.
The Amplats tension happened as Deputy President Kgalema Motlanthe was meeting union and mining companies on Friday to find a solution to the instability which has troubled the sector in the past months. – Reuters, Sapa