About 35 villagers were digging for grains of gold on Sunday in a pit at the small traditional gold mine in remote Bone Bolango district in Gorontalo province when tons of mud plunged down the surrounding hills and buried them, said Afifuddin Ilahude, Gorontalo's Search and Rescue Agency spokesperson.

He said rescuers saved five injured people on Sunday and had recovered 11 bodies by Monday. Rescuers are still searching for 19 others who were reported missing, he said.

“Relief efforts for the dead and missing were hampered by heavy rain and blocked roads covered with thick mud and debris,” Ilahude said. He said rescuers were having difficulty in evacuating three of the recovered bodies.

National Disaster Management Agency spokesperson Abdul Muhari said torrential rains that have pounded the area since Saturday also broke an embankment, causing floods of up to 3 metres (10 feet) in five villages in Bone Bolango. Nearly 300 houses were affected and more than 1,000 people have fled for safety.

Informal mining operations are common in Indonesia, providing a tenuous livelihood to thousands who labour in conditions with a high risk of serious injury or death.

Landslides, flooding and collapses of tunnels are just some of the hazards facing miners. Much of gold ore processing involves highly toxic mercury and cyanide and workers frequently use little or no protection.

The country's last major mining-related accident occurred in April 2022 when a landslide crashed onto an illegal traditional gold mine in North Sumatra's Mandailing Natal district, killing 12 women who were looking for gold.

In February 2019, a makeshift wooden structure in an illegal gold mine in North Sulawesi province collapsed due to shifting soil and the large number of mining holes. More than 40 people were buried and died.