SALT LAKE CITY, Utah, Aug 15 (Reuters) - Frustrated rescuers ran into fresh complications on Wednesday in their effort to find six men trapped in a Utah mine, as they were unable to get listening equipment through a third hole drilled from the surface.

But during a sometimes emotional press conference, mine officials said they had not given up hope of getting the miners out alive -- even though the men have not been heard from since the Crandall Canyon Mine collapsed on Aug 6.

"I know these men well. I know they would not appreciate us taking any chances and they know damn well that we're doing what we can do to get to them," mine safety manager Bodie Allred told reporters, his voice choking with emotion.

Allred, whose cousin, Kerry Allred, is one of the six men stranded some 1,800 feet (550 metres) below the surface, added: "And we're going to get there. There's no doubt about it."

Three times so far rescue crews have used drills from the surface to punch into underground mine chambers where they thought miners may have taken refugee and each time they have been unable to detect signs of life.

The third bore hole penetrated into the mine at about 10:15 a.m. local time (1615 GMT) and rescuers were hoping they would locate the men with microphones and a camera.

But a bend in the bore hole caused the microphone to become jammed some 20 feet (6 metres) above the roof line, Mine Safety and Health Administration chief Richard Stickler told the news conference, and it would go no further.

Stickler said the crews next planned to remove the equipment and install a steel casing that they hoped would allow the microphones to make it all the way into the cavity.

Progress was also moving slowly on a tunnel being burrowed through the mine that would eventually allow the six miners -- if they were still alive -- to escape. Stickler said "seismic activity" had limited tunnel progress to only 90 feet (27 metres) since Tuesday.

Mine co-owner Robert Murray said he was flying in a "second wave" of managers to relieve those who were exhausted after more than nine days working day and night on the rescue and would not give up until the missing men were found.

"I am still very optimistic that we will find these miners alive," Murray told reporters. "There is real reason to believe that."

Murray said he considers it a good sign that the roof of the mine was still intact and that there was "plenty" of water for the men to drink.

Murray has insisted that the mine's collapse was triggered by an earthquake, despite experts' assertions to the contrary.

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