A new accident occurred at the Crandall Canyon mine in Utah late Thursday, three rescue workers being killed after seismic activity caused a part of the tunnel to collapse, authorities informed on Friday.

Rescue teams have been working around the clock for eleven days to reach six miners trapped by a similar incident approximately 500 metres bellow the surface. Ground movement delayed the work several times since last Monday, but no victims were reported until last night.

Three men died and six were injured after part of the tunnel they were digging caved-in, apparently because of seismic activity, as the federal Mine Safety and Health Administration reported.

Miners are familiar with such ground movement that makes noise and can provoke collapses. It is presumed that a same phenomenon led to the accident that occurred on August 6.

Meanwhile, all rescuers were pulled out of the coal mine until further notice. Similar events caused setbacks for the rescue operation, about 130 men being forced to cease their operations several times.

For the moment, the rescue operation was stopped and authorities are analyzing the situation in order to decide whether to give green light for the work’s restart.

Three 600-metre-deep openings have been drilled from the mountain top in order to make contact with the six men, but aside from some undefined sounds picked up by special equipment there was no trace of the miners.

A fourth hole is being drilled from another location, rescuers hoping that the miners moved to another chamber with larger supplies of oxygen, after a video camera lowered into a mine chamber where the men were believed to be trapped revealed only an empty space with no sign of damage or miners.