Four mineworkers died in two separate accidents at the Driefontein and South Deep mines on the West Rand on Tuesday, Gold Fields said in a statement.

Spokesperson Andrew Davidson said three workers died and two were injured after a seismic event caused a fall of ground at the Driefontein mine at 8.17am on Tuesday.

At South Deep mine a driller's assistant died in a fall of ground at 10.30am on Tuesday.

"Investigations into both accidents will be carried out by the respective mine management teams as well as the Department of Minerals and Energy," said Davidson.

NUM spokesperson Lesiba Seshoka confirmed the deaths, saying: "The NUM condemns these senseless and preventable deaths."

These accidents bring the total number of mineworkers who died while on duty this year to 33.

The deaths come at a time when companies were organizing a dozen safety summits separately, said Seshoka.

Vishnu Pillay, head of Gold Fields' South African operations, said: "We deeply regret the loss of lives of our colleagues.

"These accidents have occurred despite considerable efforts to improve management of safety at our operations.

"We remain committed to our quest of achieving zero harm at all our operations.

"Safety is still our number one priority."