Mine collapses are not uncommon in Russia and the former Soviet Union where many facilities have not been modernised since the Communist era.
At least two miners were killed on Thursday and 28 are missing after a pit collapse in northern Russia, the owners said.
Rescue teams discovered two bodies and were scrambling to track down the missing after managing to bring more than 80 workers safely to the surface at the Severnaya coal mine in the remote Komi region, the Vorkutaugol company said in a statement.
Local emergency services in the region, some 1,200 miles (1,900 kilometres) northeast of Moscow, said the mine was hit by a "pressure burst" in the afternoon, without giving further details.
"We all hope that there will be no other victims," Vorkutaugol general director Vadim Shablakov said in a statement.
"We are doing all we can to evacuate the remaining miners as fast as possible."
Russia's Emergency Situations Minister Vladimir Puchkov flew to the artic region on Thursday evening to personally oversee the rescue operation, state-run news agency RIA Novosti reported.
Mine collapses are not uncommon in Russia and the former Soviet Union where many facilities have not been modernised since the Communist era.
In 2007 at least 108 miners died in a mine explosion in the Siberian region of Kemerovo.