Rescuers worked Sunday to recover the bodies of the last of 25 miners killed by a fire in a Siberian gold mine, while Russia's top emergency official suggested a delay in reporting the underground blaze was a fatal mistake.

Emergency workers found the bodies of the last four miners who had been missing since the fire broke out Thursday in the Darasun mine, in the Chita region about 3,000 miles east of Moscow; Emergency Situations Ministry spokesman Natalya Lukash said.

Of the 64 workers in the mine when the blaze began, 31 made it to the surface within hours.

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"From now on we will celebrate a second birthday on Sept. 7," said one of them, Dmitry Strelov, in televised comment from his hospital bed.

Eight more survivors, their faces streaked with soot, emerged from the smoke-filled tunnels Saturday, saying they managed to stay alive for two days several hundred yards underground by sticking together.

The eight were treated for hypothermia and carbon dioxide poisoning.

One miner, Nikolai Selishev, said he and his companions had found an area where fresh air was blowing and stayed there until smoke and gas lifted enough for them to move further.

Officials said last week that negligence during welding work may have sparked the blaze at the mine, which has been in operation since 1901.

The welders first attempted to put out the fire themselves and waited nearly an hour to call for help, which allowed the fire to spread quickly, according to the ITAR-Tass news agency, which cited Nikolai Kutin, deputy head of government safety watchdog agency Rostekhnadzor.

RIA-Novosti reported that more than 90 minutes passed between the start of the fire and the time a message about the blaze reached a dispatcher.

"This delay in reaction — during which people tried to deal with the situation themselves and did not inform even the leaders of the shift or the work they were doing, let alone the mine leadership — this is, of course, quite serious," Emergency Situations Minister Sergei Shoigu said in televised comments.

The gold-and-metals mine is operated by London-listed Highland Gold Mining PLC. The 105-year-old mine has been plagued with operational problems for over a year, Dow Jones Newswires reported, badly delaying the schedule for raising output and contributing to the causes of Highland's net loss last year.

Mining accidents are common in the former Soviet Union, where operators often lack funds to invest in safety equipment and technical upgrades. But Vladimir Rossikhin, of the Russian Independent Union of Coal Miners, said safety had improved in recent years amid Russia's economic recovery.

The Ministry of Natural Resources said Friday it would carry out a special inspection of safety practices at the country's mines, and an environmental official said the ministry would thoroughly check Highland's Russian operations.

Regional authorities said the Chita province would mark Monday as a day of mourning.