The miners were working some 2,625 feet underground when water from a subterranean lake leaked into a shaft above them on Thursday, blocking their way to the surface, said Col. Viktor Shkareda, head of the regional emergency department.
Seventy-one miners were in the Zapadnaya mine in the Rostov-on-Don region, about 600 miles south of Moscow, when the accident happened, Shkareda said. He said 25 miners managed to escape to other pits and reach the surface after the leak filled several shafts.
Electricity in the mine was shut off, and the miners have low batteries and no food, Shkareda said.
About 50 special mining rescue workers were trying to reach the trapped miners from neighboring shafts, he said, but it was expected to take up to 24 hours to reach them.
The trapped miners have little air, and the rescue teams were attempting to make special ventilation shafts.
According to the ITAR-Tass news agency, it was the second such accident at the Zapadnaya mine this year. Water flooded the mine in February, but no people were inside at the time, the news agency said.
Accidents are common in the Russian coal industry, and miners stage frequent protests over wage delays and declining safety standards. According to the Independent Coal Miners' Union, 68 miners were killed on the job last year and 98 in 2001.