Angry relatives complain that police and mine management have failed to produce a central register of the dead.
At least 78 people were also injured and more than 200 people arrested.
A police spokesman has told the BBC efforts were being made to contact people, but it would take some time.
Earlier, South Africa’s President Jacob Zuma announced an inquiry into Thursday clashes, calling the deaths there “tragic”.
The circumstances that led police to open fire remain unclear, but reports from eyewitnesses suggest the shooting took place after a group of demonstrators, some holding clubs and machetes, rushed at a line of police officers.
Police, armed with automatic rifles and pistols, fired dozens of shots.
“I am convinced that the Commission of Inquiry will uncover the truth and facts will emerge,” he said in a statement after meeting police and injured workers.