This is their second effort to make contact with the men. Yesterday a microphone was lowered down to a separate hole, but that also turned up nothing.

这是他们第二次尝试和矿工联系，昨天一个迈克风放在另一个洞里，但也没有结果。

youdao

An attempt to make contact with the trapped miners was unsuccessful Friday, when a microphone lowered into a narrow hole drilled into a mine cavity detected no sounds.

CNN: Camera lowered into mine cavity shows 'survivable space'

Over the following nine minutes, air traffic controllers frantically tried to make contact with the cockpit, from which only heavy breathing and electronic noises could be heard before the microphone finally went dead.

BBC: Australian 'ghost flight' still a mystery