Up to 4,000 workers at the Marikana platinum mine in South Africa -- the scene of deadly violence in August -- returned to work Friday after downing tools a day before, managers said.

"All Lonmin employees who were engaged in work stoppages on Thursday 18 October are back at work," the Lonmin mine said in a statement.

"Normalisation of operations is progressing well and is ahead of expectations."

Some miners refused to go underground on Thursday, protesting reports of police harassment after a few workers were arrested in the last week.

Employees at the mine have been back at work for almost a month, after the worst violence seen in post-apartheid South Africa prompted management to agree a substantial pay rise.

In all 46 people were killed, both workers and police, over weeks of violence that are now being investigated by a government-appointed commission of inquiry.

The panel, led by a retired judge, is expected to resume deliberations on Monday.