The men, named by Bild newspaper on Thursday as Jürgen K., 56, Michael R., 50, and Christoph K., 24, are thought to have suffocated after a routine controlled explosion released abnormal levels of deadly gas into the mine shaft in Unterbreizbach, Thuringia, where they had been working on Tuesday lunchtime.
A total of seven miners became trapped 700 metres below ground when an explosion to free potash salt from the rock unleashed a "shock wave" of toxic carbon dioxide which spread quickly through the mines' tunnels, said the paper.
Two of the men succeeded in escaping into a neighbouring shaft, and used the mine lift to get safely above ground. Another two fled into a nearby shelter, where they used a telephone to contact the mine rescue time. The three remaining miners were less fortunate and were discovered dead that evening by the rescue team.
A forensics team is now investigating how the men died. Confusingly, they had all been wearing small emergency packs on their backs containing enough oxygen to last for up to an hour. Currently there are two theories of what happened, the paper said.
"It could be that the shock wave was so big that it threw the men against the wall of the mine shaft and that's how they died," spokesman Michael Wudonig from mine operator K+S Potash told Bild. "But I think that's improbable."
More likely, said Wudonig, was that so much gas escaped so quickly that it overwhelmed the men. "We assume the men didn't manage to put their oxygen masks on or escape into a secure room. They probably suffocated."
Whether the incident was due to any oversight by mine operators remains unclear.
"Having a carbon dioxide leak is an everyday occurrence," said another K+S spokesman Ulrich Goebel on Tuesday. "But it is highly unusual to have such a large quantity seep out so that the gas penetrates the mine shaft and escapes above ground."
State prosecutors have launched an investigation into the incident, but have as yet not been able to reach the site of the explosion due to high concentrations of toxic gas.
“It could last a long time,” Markus Knapp, spokesman from the state prosecutors office in Meiningen. The mine will remain shut until the end of the week as mourners continue to pay their respects at the site.
READ MORE: Explosion kills three miners, four rescued
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