Sunday's decision to proceed with the third tunnel came after a camera lowered through a second borehole, closer to the area where the miners were working when a massive collapse occurred on Monday, showed typical mining equipment but no signs of the missing miners, said Richard Stickler, federal Mine Safety & Health Administration (MSHA) administrator, in a 2 p.m. news briefing.

A new drill pad is being prepared for that operation, which is expected to commence late Sunday night or early Monday morning. The bore hole is expected to be roughly 1,400 feet deep, about 400 shorter than the last bore hole.

Meanwhile, efforts to reach the miners advancing through the fresh-air tunnel sustained a major setback earlier today when two more "bounces" occurred, threatening to produce more cave-ins.

Although roof and wall support structures installed by rescue teams held and prevented rescuers from being damaged, MSHA and Murray Energy Inc. officials withdrew rescue teams from the mine.