Rescuers retrieved a dozen bodies of women buried under tons of mud from a landslide that crashed onto an unauthorized gold mining operation on Indonesia’s Sumatra island, police said Friday.

About 14 women were looking for gold grains Thursday in a pit roughly 2 meters (6.5 feet) deep at a small and unauthorized traditional gold mine in a remote village of North Sumatra’s Mandailing Natal district when a landslide plunged down surrounding hills and buried them, said local police chief Marlon Rajagukguk.

A two-hour search and rescue operation managed to rescue two injured women and pulled the bodies of 12 other women from the rubble, Rajagukguk said.

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He said authorities have closed illegal gold pits in the area, which was a main source of gold to be panned traditionally by villagers before Thursday’s landslide happened.

Informal mining operations are commonplace in Indonesia, providing a tenuous livelihood to thousands who labor 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.

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The country’s last major mining-related accident occurred in February 2019 when 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 died, buried in the mine pit.