Impala Platinum (Implats) said on Wednesday that two workers were missing after a shaft collapsed at its Rustenburg mine in South Africa.
Operations at the shaft were suspended when the shaft collapsed on Tuesday, trapping a total of nine workers underground before seven were rescued, Implats' investor relations officer Alice Lourens told Reuters.
She said the company - the world's second-biggest platinum producer - was trying to find the missing workers.
It was not immediately clear how much output the company had lost following the closure of the shaft, she said.
"It's difficult to quantify, it depends on an investigation ... It's to early to say," said Lourens.
The cause of the collapse at the mine had not yet been established, the company said.
Four employees were killed in January at one of Implats' Rustenburg shafts following a fire.
(Reporting by Tanisha Heiberg; Editing by James Macharia)