DONETSK, Ukraine (Reuters) -- Rescue teams are pressing on with efforts to find seven miners missing deep underground in Ukraine's Donbass coalfield more than 24 hours after an accident that killed six of their comrades.
Rescue workers have conceded there is little chance of finding the missing men alive at the Skochynsky colliery, with gas levels still high and underground temperatures of 43 Celsius.
Thirty-one teams of rescue workers and medics have been dispatched to the mine in Donetsk, the coalfield's main center.
Officials say the accident, 1,000 meters below the surface, was caused by a release of methane and a rock fall during maintenance work at the pit, equipped with some of Ukraine's most sophisticated safety equipment. Thirty-eight miners reached the surface safely.
Accidents are common in Ukrainian mines, many constructed in the 19th century and barely modernized since Soviet times.
About 200 miners died last year in accidents, but the toll has been declining.
In 2007, more than 100 in three explosions occurring over two weeks. An explosion in 1998 killed 63 miners at Skochynsky mine.