GWEN IFILL: Finally tonight: the engineering miracle behind the rescue of the Chilean miners.
On August 5, the San Jose Mine in Northern Chile collapsed, trapping 33 miners nearly half-a-mile below some of the hardest rock on Earth. Three separate drilling operations dubbed plans A, B, and C worked to get the men out.
The story gripped the world for more than 60 days. For the last month, a crew from the PBS program "NOVA" chronicled the efforts. Here are two excerpts from their documentary, starting one month into the crisis.
NARRATOR: Today, an American-built drilling rig, the Schramm T-130, arrives. It's part of a daring new rescue plan dubbed Plan B that started with a phone call from Pennsylvania-based drilling engineer Brandon Fisher.
BRANDON FISHER, Center Rock, Inc.: When we initially saw that they were planning on taking as long as Christmas, we felt that we needed to get involved and at least reach out and let people know from Chile that we have technology that could possibly help.
NARRATOR: Brandon's plan is brutal, but much faster. Instead of grinding the rock, like Plan A, his drill will smash it. Compressed air forces a piston to smash into a drill head made of hardened tungsten steel points.
These points hammer into the rock 20 times a second. This drill should be twice as fast as the Strata 950, but there's one major drawback. You can't steer it. But Brandon has a plan.
Three six-inch diameter shafts run down to the miners. They're supplying the men with food, water and medical supplies. Brandon's bold idea is to sacrifice one of these supply lines. He will use it to guide his air-powered hammer. The Plan B team have designed a special hammerhead with a guide piece on the tip that allows the drill to follow the existing pilot hole.
As Plan A continues on, Plan B starts to drill. The first 150 feet of this hole is the hardest. The drilling bit has to change direction steeply at the top as it follows the existing pilot hole.
Brandon worries that the hammerhead will jump out of the guide hole as it tries to round the curve. Plan B is a fast, but high-risk ride.
Day 65. The sun rises over a freezing Atacama Desert. As day breaks, Plan B is only 10 feet away from the miners. It's a dangerous time. The rock directly above the tunnel roof is weak. The threat of major collapse is very real.
MAN: We're going to take our time going through, talking to the miners. They will be telling us what they're seeing down there. Everyone is just completely pumped up right now.
NARRATOR: They have reached the final few feet. Now they're drilling at half speed, inching toward their target -- 8:00 a.m., Brandon Fisher's specially-designed drill smashes through to the miners.
GREG HALL, president, Drillers Supply International: The best drillers I have ever seen.
BRANDON FISHER: This is the 33rd day we were drilling.
GREG HALL: Thirty-three days, 33 miners.
BRANDON FISHER: I just can't believe we're finally here. It's just -- I don't even know what to say. I just feel like I'm ready to explode.
NARRATOR: After 65 torturous days underground, the Plan B team gives the miners their escape route.
GREG HALL: This is the hardest job I have ever been on in my life, technically and obviously emotionally. And it fought us the whole way. It really fought us the whole way. And there was a lot of times we didn't think we would make it. At the very end, you probably saw the pipe jamming. The roof bolts were catching in the teeth. And it was like, oh, great, we're not going to be able to make it. But, yes, we made it.
NARRATOR: Mission accomplished. The Plan B team leaves.