The operations at the mine, located in West Papua, were halted after a collapse that claimed 28 lives.
The Indonesian government gave approval for the restart of open pit mining operations in June 2013, and the operations have been at full capacity since 4 July, reported Reuters.
Speaking in a media conference, Freeport Indonesia president director Rozik Soetjipto said that the underground mining will take one month to run at full capacity.
The mine normally produces between 140,000 and 150,000t of copper ore every day, while production from its underground operations is 80,000t.
