The tunnel collapse at Freeport-McMoRan’s Grasberg Mine complex in Indonesia that left 28 workers dead and the mining operations suspended will have an impact of 3 million lbs of copper and 3,000 oz of gold, the company said.

The training facility is located near its largest underground mine, the Big Gossan, in Papua province. The company shut down operations at all its mines in Papua for safety checks.

For the period between May 15 and Tuesday, the company said the estimated impact on PT Freeport Indonesia’s production was about 80 million lbs of copper and 80,000 ozs of gold, MarketWatch reported.

“This was an unprecedented event in our more than 40-year history of operations in Papua,” chairman James R. Moffett and chief executive Richard C. Adkerson said. “We are taking all actions required to prevent future incidents and to assure the safety of our workforce.”

The Grasberg minerals district in Indonesia is one of the world’s largest copper and gold deposits.

Freeport-McMoRan said PT Freeport Indonesia has conducted safety inspections throughout its operations and is working with the Indonesian Department of Energy and Mineral Resources and other authorities to resume operations in a phased approach.

Because of the temporary disruption, PT Freeport Indonesia notified its customers of a force majeure event under its concentrate sales agreements.