Villagers had been digging for grains of gold in the remote village in the Solok district of West Sumatra province when mud plunged down the surrounding hills and buried them on Thursday.
Several people managed to escape and some were pulled out by rescuers, local search and rescue agency chief Abdul Malik said.
Eleven people were injured.
Malik said rescuers recovered 12 bodies, revising an earlier death toll of 15 after officials discovered that lack of communications and the remoteness of the village had affected the counting of the victims.
Two other people are believed missing under tons of mud, he said.
Rescuers earlier said the devastated area could only be reached by walking for four hours from the nearest settlement.
"Relief efforts for the dead and missing were hampered by rugged terrain and blocked roads covered by thick mud and debris," Malik said, adding that many residents also did not want outsiders, including search and rescue officers, to enter their traditional mining areas.
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 July when a landslide crashed into an illegal traditional gold mine in Gorontalo province on Sulawesi island, killing at least 23 people.
In April 2022 a landslide hit another gold mine in North Sumatra's Mandailing Natal district, killing 12 women.
In February 2019, a makeshift wooden structure in an illegal gold mine in North Sulawesi province collapsed partly due to shifting soil.
More than 40 people were buried.
