MOSCOW — Rescuers plunged into the dangerous rubble of Russia's largest coal mine Monday in search of dozens trapped miners, but the head of the rescue operation said hope was dimming for finding them still alive in the city-sized maze of black and smoky tunnels deep underground.
The death toll rose Tuesday morning to 43, Russian news agencies reported.
On Monday, rescuers recovered 20 more bodies from the Siberian mine that was shattered by two explosions over the weekend.
"The rescue work is continuing of course, but unfortunately the work is becoming more difficult," Emergencies Minister Sergei Shoigu reported to President Dmitry Medvedev by video link. "Unfortunately the bodies that have been pulled out and their injuries tell us that there is less and less hope of finding anyone alive."
More explosions feared
Many of the dead were rescue workers who had gone into the mine after the first of the blasts. A second, more powerful blast then destroyed the main air shaft, which had a diameter of five meters (16.5 feet), and a five-story building over the mine. Black soot covered the area.
High levels of methane gas remaining in the mine had raised fears of further explosions and prevented rescue workers from resuming their search until early Monday.
Shoigu said the rescuers had made it 1.5 kilometers (almost a mile) into the mine and were hanging up oxygen tanks along the way so they would have sufficient air to make it back out. They were monitoring methane levels as they went.
A bigger danger, he said, was now posed by rising water levels deep in the mine. Rescuers have until Tuesday night or Wednesday morning to reach about a dozen people presumed to be in two locations that are being flooded, he said.
The first blast, believed to have been caused by methane, hit the Raspadskaya mine just before midnight Saturday. There were 359 workers below ground at the time and the majority managed to get out. A total of 69 people were hospitalized Monday.
The second explosion occurred about 3½ hours later, after rescuers had entered the mine. The bodies of 12 miners and rescue workers were recovered on Sunday, the Emergencies Ministry said. A further 20 bodies — all rescue workers but one — were found on Monday.
All communication with the trapped miners was lost, Shoigu said.
Medvedev ordered the prosecutor general to determine what caused the accident at Raspadskaya. Speaking at a government meeting, the president described the mine as one of the best equipped in the country.
More than 500 emergency workers from around the country were brought to Mezhdurechensk to help restore ventilation to the mine and rebuild mine shafts so the search for those missing could resume.
The first few brigades of rescue workers went down into the mine early Monday. By afternoon, 14 brigades of five to six rescuers each were working in the mine shafts.
The Raspadskaya mine is 500 meters (1,650 feet) deep and has 370 kilometers (220 miles) of underground tunnels. It has produced about 8 million tons (8.8 million short tons) of coal a year, according to the company's website.
There was no information on what set off the blast. Mine explosions and other industrial accidents are common in Russia and other former Soviet republics, and are often blamed on inadequate implementation of safety precautions by companies or by workers themselves.
The deadliest explosion in Russia's coal mines in decades occurred in March 2007, when 110 miners were killed in Kemerovo.
There have been a number of deadly coal mining accidents around the world in recent months.
The United States was hit with its worst coal mining disaster in 40 years when 29 miners died April 5 in an explosion at a West Virginia mine.
In China, where the mining industry is the world's deadliest, at least 33 miners died after a mine flooded on March 28. The flood trapped 153 miners, but most were eventually rescued.
The Associated Press and Reuters contributed to this report.