South African police fired tear gas, rubber bullets and stun grenades to disperse protesters near a mine owned by the world's top platinum producer.
The unrest Wednesday in Rustenburg, at a mine owned by Anglo American Platinum (Amplats), raised fears that unrest in South Africa's mining sector is not over.
Hours earlier, Lonmin platinum mines agreed to give its workers a hefty pay raise following a violent five-week strike in which 45 people were killed.
Police spokesman Dennis Adriao said the crowd in Rustenburg had gathered illegally at an informal settlement. He said police took action after the group refused orders to disperse.
The mining industry is South Africa's largest.
The union representing South African platinum mine workers signed the deal with Lonmin late Tuesday.
The agreement calls for workers to get a 22 percent pay raise, less than what they originally demanded. They will also receive a one-time cash payment of $250 to compensate for the time they were off the job.
The Lonmin workers are to return to work on Thursday.