Timika, Papua. Rescue teams at Freeport Indonesia’s (PTFI) Grasberg Block Cave mine in Mimika, Central Papua, were still working Wednesday to evacuate seven contract workers trapped underground following a landslide that struck earlier this week.

The incident occurred late Monday night when a massive flow of wet material surged into the underground mine tunnels, blocking access routes and leaving the workers stranded, according to company officials.

“Their condition is reported to be safe and we remain in communication with them by radio. What we worry about is the oxygen supply inside, hopefully they have reserves,” Tembagapura Police Chief Firman told state news agency ANTARA on Wednesday.

Emergency response teams have been attempting to clear the blocked passageways, but the sheer volume of material has slowed progress.

Freeport has halted all underground operations at the Grasberg Block Cave to focus on the rescue.

“The location of the trapped workers is known, and they are believed to be safe. Crews are working to clear access for a safe and swift evacuation,” Katri Krisnati, Freeport Indonesia’s vice president of corporate communications, said in a written statement.

Freeport confirmed all other workers in the mine are safe.

Energy and Mineral Resources Minister Bahlil Lahadalia said the government would dispatch a team to Grasberg in the aftermath of the landslide to oversee safety and emergency handling.