HUNTINGTON, Utah &#8212 Officials extinguished nearly all hope of finding any of the six miners alive on Sunday, nearly two weeks after the men were trapped in a violent collapse deep with a mine.

The latest results from a fourth hole drilled more than 1,500 feet into the mountainside found the air quality could not sustain life, said a top executive of the company that co-owns the Crandall Canyon Mine.

“It’s likely these miners may not be found,” said Rob Moore, vice president of Murray Energy Corp.

It was a marked shift in tone after days of public, unflinching optimism that the men would be rescued.

There has been little evidence that the miners had survived the initial Aug. 6 collapse.

Workers have gained limited access to the mine through four boreholes in which video cameras and microphones were placed. Rescuers banged on a drill bit and set off explosives Saturday, hoping to elicit a response from the men, yet their efforts still were met with silence.

Engineering experts from around the nation gathered at the mine Sunday to try to figure out a safe way of reaching the missing men.

Underground tunneling has been halted since a mountain “bump” Thursday killed three rescuers and injured six others.

MSHA summoned experts from the National Institute of Occupational Safety and Health, West Virginia University and private engineering firms in the hope that they can develop a safer way of tunneling toward the trapped miners. Their first meeting at the mine started Sunday morning.

The experts were studying mine maps and planned to go underground, into a part of the mine deemed safe, to examine the coal pillars holding up the roof. The hope is that they can come up with a way to safely go back underground.