An explosion ripped through a coal mine Wednesday in central West Germany, and police said a collapsed shaft was hindering efforts to reach 58 miners trapped more than 300 feet below ground.

Mayor Bernd Hessler said rescuers briefly established radio contact with five trapped miners who reported they were uninjured before the radio link was interrupted.Earlier, rescuers tried unsuccessfully to establish contact with the trapped miners for nearly four hours.

Dense smoke spread over the area after the blast in this town 70 miles northeast of Frankfurt. Hundreds of rescuers rushed to the scene, including several helicopters.

An engineer for the company that owns the mine said initially that 56 miners were believed trapped by the 12:30 p.m. blast. Later Wednesday, police said 58 miners were trapped.

Hessler said the miners apparently were trapped in separate groups in several places underground.

Eight workers were seriously injured on the surface by flying debris from the explosion and taken to a hospital, police said.

Before the radio contact was made with the five miners, police said there was little chance of finding many survivors.

Rescue crews managed to get about 300 feet underground before the shaft collapsed. "This reduces the chance of finding many survivors," a police spokesman who requested anonymity told reporters.

He said rescue crews were pumping oxygen into the shaft.

Radio reports said the blast may have been caused by some 4,500 pounds of explosives that were recently delivered to the mine.

"It was like an earthquake," one unidentified mine worker told Hesse State Radio.

Gerhard Heinz, an engineer for mine owner Preussen Elektra, said the explosion occurred in a pit between 200 and 450 feet below ground.