Rio said its decision to restart followed "a stabilisation of the security situation around the mine, supported by the national and provincial government, as well as substantive engagement with host communities and their traditional authorities".
The mining major said operations would be ramping up to capacity as soon as possible, but for the time being the force majeure it declared on customer contracts early July would remain in place.
"The safety and security of our people has been our priority throughout and we recognise the collaboration and constructive dialogue we have had with all stakeholders to get us into a position where we can restart operations and resume contributing to the host communities, KwaZulu-Natal and South Africa," Rio Minerals chief executive Sinead Kaufman said.
"I also acknowledge the resilience and dedication shown by all our people at RBM over the past weeks."
The shutdown at RBM at the end of June followed the death of RBM general manager of operational services Nico Swart, who was fatally shot late May while on his way to work.
RBM is a joint venture between Rio Tinto (74%) and Blue Horizon, a consortium of investors and the mine's host communities.
The operation is a major global producer of heavy mineral sands.
