US:A microphone lowered 549m (1,800ft) into a collapsed Utah mine on Thursday night picked up no signs that six trapped workers were still alive.
But an air sample taken in the cavity where the men were thought to be working showed that there was enough oxygen for them to breathe. Mine authorities insisted there was still hope that the men could be alive. "I wouldn't look at it as good or bad news. The work is not done," Bob Murray, chairman of Murray Energy, said on Thursday.
"They're going to stay alive in that atmosphere." The miners have been trapped deep in the mine in central Utah since it collapsed on Monday. The cause of the collapse has remained disputed, with mine authorities saying it was caused by an earth tremor. However, seismologists have said the only tremor recorded at the time was caused by the collapse of the mine.
Hope now resides with a second, larger hole being drilled into the mountainside. Rescuers plan to lower a camera and food down the hole, which was expected to reach the cavity at midnight last night. Crews were clearing the mine shafts in the hope of reaching the spot where the men were last known to be working.
Meanwhile, an accident at an air shaft under construction in Gibson County Coal, a southern Indiana mine, killed three people yesterday, police said. Authorities did not believe there had been a cave-in or an explosion.