Russian authorities are insisting that the underground explosions that killed 36 people in an Arctic mine over the weekend were the result of natural causes, not negligence or fraud.
Four miners died when explosions fueled by high methane levels tore through the Severnaya coal mine north of the Arctic Circle on February 26. Another six people attempting to rescue the coal miners were killed by another explosion on February 28, which is believed to have also killed 26 miners trapped in the vicinity where they were searching.
Russia's Investigative Committee opened a criminal probe into the disaster, the deadliest to hit the industry since 2010, dispatching investigators and forensic experts to look into possible safety violations.
But Deputy Prime Minister Arkady Dvorkovich said on February 29 that preliminary evidence shows a sudden surge of methane caused the incident -- something that no monitoring system could have stopped.
"At this point, based on the analysis of the data from both Rostekhnadzor (Russia's industrial safety watchdog) and the Investigative Committee, it is clear that there was an abrupt outburst, increase in methane concentration. ... There was no gradual methane concentration increase, sensors did not register anything of the kind, so it was almost impossible to prevent the outburst using sensing devices," he said.
Dvorkovich said the mine operator, Vorkutaugol -- a unit of steelmaker Severstal, which is headed by Russian billionaire Alexei Mordashov -- acted "according to the rules."
"This is a terrible tragedy for Russia and for our coal industry," he said as he explained that rescue efforts had been abandoned because no further survivors are considered likely to be found due to the fire that continues to rage underground.
Pechora Alexander Goncharenko, head of Rostekhnadzor's regional branch, said preliminary evidence suggests the incident was "a natural disaster" caused by methane leaks that occur naturally in coal mines.
Methane explosions occur every few years in Russian mines and elsewhere. In 2007, an explosion at a mine in Ulyanovskaya in Siberia killed 110 people.
Vorkutaugol has said safety measures were recently ramped up at the facility and that it would continue to pay all the workers at the Severnaya mine and find employment for them at the company's other mining sites.
But trade union members, miners, and relatives of those that died say they had serious concerns about the levels of methane in the pit and that workers feared something could go wrong.
"My father was coming home and warning about the strong fumes and the high level of methane," said Daria Tryasukho, whose father was one of the miners killed.
"He talked about this almost every day, but the management at Severnaya closed their eyes and let people go underground," she wrote in a posting online.
Miner Mikhail Momot has been on break from working in the Severnaya mine since November, but his older brother Konstantin was killed in the blast.
Momot told AFP that workers had regularly noticed discrepancies between the various devices monitoring methane in the mine.
"It was systematic that the amount of methane shown on the official monitors set up in the mine and our own individual monitors didn't coincide," Momot said. "The management couldn't not know about this."
"Since the beginning of February, the guys were telling me that there was a lot of gas, but they had to go on working," Momot said. "The bosses usually reply that if you don't want to work, you can quit. But where could I go?"
A Vorkutaugol spokeswoman told AFP it was impossible to falsify information on the monitors and that miners' individual monitors often differ from the stationary ones because they are moving constantly.
With reporting by AFP, dpa, and TASS