Rescue teams trying to reach the six miners trapped in a coal mine in Utah on August 6 managed to drill a fourth hole into the mine chamber on Saturday and lower surveillance equipment, hoping to pick up any sign from the workers.

But microphones again remained silent, while images captured by a video camera were being analyzed on Sunday. Even so, rescuers refused to give up and said a fifth hole will be drilled in another location that would hopefully scatter the mist surrounding the fate of the six miners.

Meanwhile, work at the rescue tunnel has been ceased since Thursday when seismic activity caused part of the structure to collapse, three men being killed and six injured. Authorities and experts were expected to decide on Sunday whether to resume operations at the tunnel or find an alternative solution.

The three deceased men were identified as being Gary Jensen, Brandon Kimber and Dale Ray Black. Jensen was a specialist from the Mine Safety and Health Administration, while the two other men were colleagues of the miners sealed off underground.

Previous attempts to reach the men trapped inside the Crandall Canyon coal mine by drilling three holes from the mountain top have also failed, footage taken by cameras revealing an empty but intact space.

The fact that the structure wasn’t affected and no bodies were seen, raised the hopes of rescuers and families that the six miners could have moved to another chamber with richer supplies of oxygen and water.

Tests carried out showed that the air contained enough oxygen to sustain life for several days, but no signs from the miners were recorded by the equipment. In such situations miners use to tap on the walls to make their presence felt and help rescuers located them more easily.