Another 239 people were rescued.
The state-run Tass and RIA-Novosti news agencies quoted emergency officials as saying there was no chance of finding more survivors at the Listvyazhnaya mine in the Kemerovo region of southwestern Siberia.
The Interfax news agency quoted a representative of the regional administration, who also put the death toll from Thursday’s accident to 52, saying they died of carbon monoxide poisoning.
It was the deadliest mining accident in Russia since 2010, when two methane explosions and a fire killed 91 people at the Raspadskaya mine in the same Kemerovo region.
A total of 285 people were in the Listvyazhnaya mine early Thursday when the explosion sent smoke that quickly filled the mine through the ventilation system. Rescuers brought to the surface 239 miners, 49 of whom were injured, and found 11 bodies.
Later in the day, six rescuers also died while searching for others trapped in a remote part of the mine, news reports said.
Regional officials declared three days of mourning.
Russia’s deputy prosecutor, Dmitry Demeshin, told reporters that the fire was most likely caused by a methane explosion caused by a spark.
The surviving miners described their shock after reaching the surface.
“Impact. Air. Dust. And then we smelled gas and just started going out as many as we could,” one of the rescued miners, Sergey Golubin, said in the TV reply.
“We were not even aware of what was happening in the beginning and we took some gasoline in.”
Another miner, Rustam Chebelkov, recalled the dramatic moment he was rescued with his comrades when chaos engulfed the mine.
“I crawled, and then I felt them grab me,” he said.
“I reached out to them, they could not see me, visibility was poor. They grabbed me and pulled me out, if not for them, we would be dead. “
Explosions of methane released from coal mines during mining are rare, but they cause the most deaths in the coal mining industry.
The Interfax news agency reported that miners have oxygen supplies that usually last for six hours and can only be stretched for a few more hours.
Russia’s investigative committee has launched a criminal investigation into the fire over breaches of security regulations that led to deaths. It said the mine director and two senior executives were detained.
President Vladimir Putin expressed his condolences to the families of the dead and ordered the government to offer all necessary assistance to the wounded.
Thursday’s fire was not the first fatal accident at the Listvyazhnaya mine. In 2004, a methane explosion killed 13 miners.
In 2007, a methane explosion at the Ulyanovskaya mine in the Kemerovo region killed 110 miners in the deadliest Soviet-era mine accident.
In 2016, 36 miners were killed in a series of methane explosions at a coal mine in Russia’s far north. In the wake of the incident, authorities analyzed the safety of the country’s 58 coal mines and declared 20 of them, or 34 percent, potentially unsafe.
The Listvyazhnaya mine was not among them at the time, according to media reports.
Russia’s state technology and ecology watchdog, Rostekhnadzor, inspected the mine in April and recorded 139 violations, including violations of fire safety rules.