Rescue teams managed to reach the space where six miners are believed to be trapped at a coal mine in Utah, but weren’t able to communicate with the workers.

The rescuers drilled a small tunnel from the mountain top into the mine chamber and lowered a microphone, hopping to pick up a sound that would scatter all worries about the miners’ fate.

But the device didn’t transmit any sounds and many began fearing the men didn’t survive the accident. For still unknown reasons, a mine shaft crumbled Monday at the Crandall Canyon Mine in northwestern Emery County, Utah and trapped six men at a depth of 500 meters.

According to Robert Murray, the mine’s owner, air quality tests revealed that the air inside the chamber contains enough oxygen to maintain the workers alive.

“It means, that if they're alive they'll stay alive,” Murray optimistically said.

Despite the discouraging lack of communication, rescuers said the workers could be further away from the small tunnel they drilled and couldn’t see the device and make contact with people above.

A second opening is being made and is expected to reach the same target on Saturday. Its purpose is that of sending supplies down and a video camera to get a better picture of the miners’ health condition.

Meanwhile, work at the main tunnel is continuing as planned, being estimated to breakthrough in five or six days. The miners are believed to be sealed off in a space located 6.5 kilometers from the main entrance.

Investigations will determine the accident’s cause, as the company operating the coal mine near Huntington claims that seismic activity determined the shaft to cave-in. Experts sustain seismographs recorded the tunnel’s collapse and not an earthquake.