MOSCOW — Descending into the smoking pit of a coal mine after methane explosions triggered underground fires, six rescue workers were killed Sunday in a failed attempt to reach 26 stranded miners in northern Russia.
On Sunday, Russia's most senior federal disaster official declared the rescue operation over and all the missing miners, who had been trapped by a cave-in, were dead.
"The circumstances in the affected part of the mine did not allow anyone to survive," Vladimir Puchkov, minister of emergency situations, said in televised comments. "In the underground space where the 26 miners were, there were high temperatures and no oxygen."
The bodies of four miners were recovered after the initial disaster Thursday when methane gas, a common hazard in coal seams, exploded in two locations about 2,560 feet underground in the Severny mine.
The six people killed Sunday, five members of a specialized rescue brigade and an employee of the mine, died in a third methane explosion as they tried to get to the trapped miners. That brought the death toll to 36, among the highest for a mining accident in Russia in recent years.
The disaster struck in one of the harshest environments for mining, in the Arctic coal town of Vorkuta, far north of Moscow in the European portion of Russia.
In the post-Soviet period, tens of thousands of miners left the town and several shafts were abandoned, but the rich coal deposits remained a lure for companies to operate there, despite the hardship.
Poor safety standards have plagued coal mines in Russia and other former Soviet republics. After a methane explosion in a Siberian mine killed 108 miners in 2007, in the worst such disaster in recent Russian history, the authorities fired five mine safety inspectors for allowing the site to operate even though a methane gas detector had been deliberately disabled to avoid the expense of halting work during gas buildups.
With rescue efforts over at the Severny mine, mining engineers with Vorkutaugol, a subsidiary of Severstal, a Russian steel-maker, were considering approaches to extinguishing the coal fires still blazing underground.