Indonesian authorities pulled out 19 badly hurt miners after the collapse of an illegal mine which killed 4, more trapped.
Indonesian authorities Wednesday ramped up efforts to find 37 people feared buried by the collapse of an illegal gold mine on the island of Sulawesi that killed at least four people.
Rescuers used spades and ropes to pull out 19 badly injured miners and found four others dead.
Officials said they could hear the voices of some of those trapped in makeshift mining shafts in a muddy hillside in the Bolaang Mongondow area of North Sulawesi province, and believed many were still alive.
"We are able to detect that many of them are still alive because we can hear their voices, as there are some places where air is getting in and out and there are gaps in the mud," Abdul Muin Paputungan of Indonesia's disaster agency said.
"The land contour is worrying, with an 80-degree slope, so it's pretty steep, and we don't want any unwanted things to happen," said local police chief Gani Fernando Siahaan.
An illegal mine in Indonesia collapsed Wednesday due to a landslide which was a result of supporting beams crumbling "due to unstable land and numerous mining shafts." These accidents are rather frequent in the country, as a result of inadequate regulations and construction.
While small-scale mining is banned, it is common in rural areas. Many people are pressured into illegal mining in a country experiencing a lack of employment opportunities.
Indonesia's disaster mitigation agency said at least 60 officials and volunteers were involved in the rescue effort but were using simple tools because conditions remained dangerous, with the land still prone to shifting and sliding.
The issue of mining safety was thrust back into global prominence this year after a dam in Brazil holding back mining waste burst, killing more than 300 people.
Resource-rich Indonesia has a patchy record on mining safety, particularly small-scale unlicensed mines. At least five people were killed in the same area of Sulawesi last year after an illegal mine collapsed during heavy rain.