Mezhdurechensk, Russia: Rescuers struggling through the blast-shattered corridors of a Siberian coal mine have nearly reached the last area where any of 30 missing miners could still be found alive, Russia's Emergencies Minister said on Wednesday.
But little time remains for the potential rescue of anyone still alive three days after a pair of explosions shook the Raspadskaya mine, Russia's largest underground coal mine.
"We've got a day to bring out miners, if they're there," minister Sergei Shoigu told reporters.
His ministry said on Wednesday that the confirmed death toll in the blasts had risen to 60.
Shoigu said that concentrations of volatile methane in areas of the mine are as much as three times the amount considered safe and that full ventilation to the mine wouldn't be restored for at least another day. There are fires still smoldering after the explosions and officials are concerned that full ventilation could feed those flames and set off new blasts.
Asked whether he thought any survivors might be found after so many days, Shoigu said "My profession makes provisions for only one answer -- we hope that, yes, they are there."
Many of the dead were rescue workers who went into the shafts after the first blast late on Saturday and were caught in the second explosion -- which was so powerful that it shattered the main shaft and a five-story building at the mine head. The mine is in the Kemerovo region about 3,000 kilometers (1,900 miles) east of Moscow.
Both the explosions are being blamed on methane, and Prime Minister Vladimir Putin on Tuesday questioned why rescuers were sent into the mine without a preliminary assessment of the gas concentration, according to the RIA Novosti news agency.
The head of the mine rescue service, Alexander Sin, said rescuers are under orders to immediately render assistance, the agency reported.
Putin ordered officials to investigate "how production technology was observed, how control instruments operated, what measures the mine managers took to raise reliability, what was the state of individual means of protection and how rescue operations were organized."
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.
But regional governor Aman Tuleyev was quoted by the business newspaper Vedomosti as saying the mine was one of the world's most technically advanced.
The deadliest explosion in Russia's coal mines in decades occurred in March 2007, when 110 miners were killed.
The Raspadskaya mine produces about 10 percent of Russia's coking coal, Vedomosti said, and a long interruption of production could affect Russia's steel industry.