CORRECTED - Workers hold sit-in at S.Africa platinum mine-union

(Corrects mine name in paragraph 2)

JOHANNNESBURG Oct 19 (Reuters) - More than 100 miners at a South African platinum mine owned by African Rainbow Minerals (ARIJ.J) and Impala Platinum (IMPJ.J) staged a sit-in on Monday and demanded that a manager at the mine be fired, a union said.

The National Union of Mineworkers (NUM), South Africa's largest union said workers at Two Rivers mine had refused to leave the underground mine where they were working when their night shift ended on Monday morning.

It said another 500 workers were unable to go underground to start their morning shift.

The workers have called on mine officials to dismiss the manager, saying he fired four workers without proper justification, the union said.

Implats, the world's second largest platinum producer, said last month it expects to lose 100,000 ounces in output of Platinum Group Metals (PGMs) in the financial year to end-June as a result of work stoppages during a wage strike and following fatalities at its operations.

The company supplies a quarter of the world's platinum. (Reporting by Muchena Zigomo, editing by Anthony Barker)