SPECIAL REPORT | FULL COVERAGE

'We are approaching the moment of truth'

Jody Frantz after completing his shift on the drilling rig used in the Quecreek mine rescue attempt.

SOMERSET, Pennsylvania (CNN) -- During the night, someone tied an American flag halfway up the steel tower of drilling rig No. 2, a symbol of the hope and determination that prevails over the drilling site this morning.

At dawn, the rescue shafts were still about 100 feet from the trapped miners.

There is hope. Rig No. 1 has been drilling steadily through the night. By 7 a.m., the drillers reported they had reached a depth of 150 feet. Drilling is going smoothly, the workers said, and progressing now at a rate of about 30 feet per hour.

CNN NewsPass Video    •  CNN's Jeff Flock visits an abandoned Pa. mine   •  Surveyor used GPS to locate miners   •  Rescued miners go home   •  Miners express appreciation  MORE STORIES   •  Pennsylvania panel to explore mining accident   •  Flooded mine could be idle for months   •  Pa. governor: Mine's operator 'owes answers'   •  A turning point in the rescue effort   •  Miners braved harrowing conditions   •  Previous mining accidents were minor » Story archive  RESOURCES   •  Jeff Goodell: Despair turns to joy   •  Gov. Schweiker: Mine probe to seek answers   •  Rescued miner: 'It was a team effort'   •  Why we burn coal  EXTRA INFORMATION   •  Gallery: The rescued miners   •  Gallery: Rescue quotes   •  Graphic: Diagram of the Quecreek Mine   •  Map: Mining accident   •  Timeline: What happened, and when

If all goes well, rescuers hope they will reach the trapped miners today.

Drilling plagued by problems

Rig No. 1, which was the first to begin drilling in the early hours of the rescue attempt, continues to be plagued by problems.

After replacing a broken bit Friday afternoon, drilling resumed last night, only to halt again when the bit ran into unexpected problems and had to be changed several times. Worse, a layer of bedrock is dulling the new bits.

"We went through $30,000 worth of bits in 24 hours," one exhausted driller said as he took a quick break to gulp down coffee and a doughnut.

The mood at the site right now is tense, hopeful and very quiet.

The mine rescue teams are going over equipment one more time. Navy personnel in fatigues watch over five high-tech decompression chambers that have been brought in case miners had to be treated for the bends.

A blue emergency services tent has been set up with a cot and medical supplies. As one rescue worker put it, "We are approaching the moment of truth."

Jeff Goodell is the author of "Sunnyvale: The Rise and Fall of a Silicon Valley Family." He is working on a book about coal and energy in the United States.