Indonesia's Energy and Mineral Resources Minister says Freeport McMoRan must obtain his permission before re-opening the Grasberg mine in Papua.
According to the Jakarta Globe, Jero Wacik has told the company that underground mining is not yet allowed and they are waiting for the result of the investigation prompted by last month's deadly tunnel collapse.
A union representing 18,000 of the more than 24,000 workers at the mine says its members will not return to work until investigations into the accident are complete.
A union spokesman Virgo Solossa says the decision is in line with Freeport policy to halt operations following accidents while probes were still ongoing.
The company said last week that it had already re-started operations on Tuesday.
The president director of Freeport Indonesia Rozik Soetjipto says the decision is the company's whether the government gives permission or not.
On Friday, another accident at the mine killed a truck driver.