"Factories' operations continued running," spokesman Dedy Kurniawan, told Reuters, saying the situation has returned to normal since the protest. The IMIP compound has capacity for at least 30 nickel processing lines.

A group of workers staged protests on Saturday which led to some property damage, according to local media reports.

The spokesman said the protesting workers were demanding leave of absence, "which we have given, but we need to follow COVID-19 protocols".

He said workers that are coming back to work need to finish a quarantine period before they can take over from workers who have been granted leave of absence.

(Reporting by Fransiska Nangoy; Editing by Kenneth Maxwell)