>> reporter: absolutely, brooke, because as you say 120 feet, that was the latest fig that the experts have given us, the distance between the drill and the roof of the tunnel where the miners are holed up. what's then going to take place? what goes on in a time line after that, after the breakthrough is the engineers then decide over the space of about 24 hours whether they've got to encase, put steel encasing the whole lengths of that rescue shaft. now, that would be to prevent rock falls. but talking to some of the technicians back and forth who have been around this area, they say they think they're only going to have to encase the first 100 yards. and that will mean that the miners could be coming out of that hole between two and eight days after that rescue shaft is finally drilled and that will certainly be good news for the miners of course but also for the families who have had such an anxious wait. brooke. >> between two and eight days