Thirty miners are still missing following two blasts on Saturday at the Raspadskaya coal mine in Siberia's Kemerovo Region, the Russian news agency RIA Novosti reports.
At least 99 miners were injured in the explosions.
Nine teams are currently trying to reach the area where the missing miners were working at the time of the first explosion.
The Raspadskaya mine is Russia's largest coal mine, producing 10 percent of the country's coking coal.
The mine is known to have large concentrations of deadly methane gas.
Russian President Dmitry Medvedev has ordered rescue operations to continue until all possible efforts have been made to reach those trapped underground.