Two people were killed and two more injured and two went missing after an explosion at Gaisky ore-dressing facility in Orenburg region, Interfax was told at the press service of the regional department of the Emergency Situations' Ministry.
"Two killed workers and two injured were discovered at the scene," a spokesman for the department said.A search for two more people is under way, he said.
Previously the Emergency Situations' Ministry reported that an unscheduled explosion occurred when explosives were planted in the mine.
"Workers are evacuated to the surface. The operation of the mine has been suspended. Two units of the mine rescue service are operating," a posting of the ministry website said.