The death toll from a massive gas explosion in an Indonesian coal mine rose to 31 on Wednesday, as rescue workers all but gave up hope of finding any survivors, officials said.
Rescuers pulled another 16 bodies from deep within the mine in West Sumatra province, which collapsed after an explosion of methane gas on Tuesday, disaster response official Adriyusman told AFP from the scene.
"A total of 16 bodies have been pulled out today. They're all burnt. The latest death toll has risen to 31," he said.
A small but unspecified number of miners remain unaccounted for, presumed dead, officials said.
"There's a large chance that they're already dead because there's a lot of carbon dioxide there," provincial disaster management chief Ade Edward said.
The blast at the mine in Sawah Lunto district sent flames 50 metres into the air and left a huge crater on the surface, officials have said. The cause of the explosion was not known.
A dangerous concentration of methane was hampering rescue efforts.
"If we look at those that have been taken out I don't think it's likely (the others survived). It's up to God's will," Adriyusman said.
Miners were using traditional methods with few modern safety measures in place.
Health ministry crisis centre head Rustam Pakaya said many of the bodies had been found around 150 metres (492 feet) below the surface.
Accidents are common at Indonesian mines, especially at illegal digs with no safety precautions, industry sources said.
A gas drilling operation linked to one of the country's biggest conglomerates allegedly triggered a massive mud volcano on Java in 2006, killing 13 and displacing some 40,000 people.
Indonesia has the largest coal reserves in the Asia-Pacific region behind Australia, India and China, according to the World Coal Institute.
It is the world's second largest coal exporter after Australia.