Methane levels in the west Siberian mine where two blasts killed at least 30 people at the weekend were not excessive, an official from the Raspadsky Coal company said on Monday.
Some 60 people are still missing after explosions at Russia's largest coal mine, located near the town of Mezhdurechensk in the Kemerovo Region, in the space of four hours late on Saturday and early on Sunday.
More than 50 people were also injured in the blasts.
"It's difficult right now to draw any conclusion [as to the cause of the blast]. All the indicators showed that methane levels were normal," Raspadsky deputy construction head Vladimir Goryachkin told journalists.
Emergencies Minister Sergei Shoigu earlier said that time was running out for 13 people, including rescue workers who went into the mine after the first explosion, in two locations due to rising water levels.
He said the damaged drainage system meant rescue workers had around 48 hours to carry out a mission to save their trapped colleagues and miners.
In other developments, Prime Minister Vladimir Putin said the state would pay one million rubles (just over $33,000) to the families of the deceased. He also said those people who suffered serious injuries would receive 400,000 rubles and people with less serious injuries 200,000 rubles.
Kemerovo Region governor Aman Tuleyev, who has taken charge of the rescue operation, said work was underway to provide housing and social benefits for the families of the dead.
"Concrete people will be attached to every family to assist in resolving social issues," a spokesperson told RIA Novosti.
This is not the first deadly accident in the Raspadsky Coal-owned mine. In late January, a worker was killed when ceiling collapsed in the mine. On March 30, 2001, a methane blast killed four miners and injured six. In 2008 the mine was closed for two weeks due to numerous safety violations.
MEZHDURECHENSK, May 10 (RIA Novosti)