Global miner Rio Tinto said operations at its South African unit Richard Bay Minerals (RBM) will resume in early January after cutting back because of security concerns for its workers.

Rio said regular production by RBM, which produces ilmenite ore for titanium from mineral sand deposits, will be reached in early 2020, and that it was contacting customers who were earlier told about disruptions to their supply.

"A phased restart is now in progress across the operation," Rio Tinto said in a statement.

There have been a number of violent incidents at mines across South Africa, including robberies, that have raised questions about the lack of security and the threats they pose to the industry.