By Michael Taylor and Kanupriya Kapoor
JAKARTA (Reuters) - Freeport McMoRan Copper and Gold Inc
The Arizona-based company has slowly resumed open-pit mining at its Grasberg complex in eastern Indonesia, more than a month after a training tunnel collapsed, killing 28 people in one of Indonesia's worst mining accidents. Underground production remained shut.
"The open-pit is already allowed to be open," Freeport Indonesia President Director Rozik Soetjipto said in a telephone interview. "At the beginning of course, there will only be a very, very small amount of production because we have to prepare everything and gradually increase production."
An energy ministry spokesman said the government granted its approval late on Friday after state officials completed their investigation.
Union miners, who make up three-quarters of the 24,000 Freeport workers, were returning to work at the Grasberg mine.
"What we are doing now is mainly maintaining the mine and equipment because it has been left by workers for a period of time," said union spokesman Juli Parorrongan.
The open-pit mine normally produces around 140,000 metric tons (154,324 tons)of copper ore per day, while output from underground operations is 80,000 metric tons.
Freeport was forced to declare force majeure on shipments due to the prolonged closure of the mine.
(Additional reporting by Fergus Jensen and Yayat Supriatna; Writing by Randy Fabi; Editing by Clarence Fernandez)