MOSCOW, Jan 20 (Reuters) - At least four miners died when fumes filled the shaft where they were working in Russia's main coal-producing region on Sunday, Russian news agencies reported. Searches for another four missing men had to be suspended after levels of methane in the mine in the Kuznetsk Basin reached dangerous levels, the RIA and ITAR-Tass news wires said. Sixty-nine miners managed to escape, they added.