Chile ? The 33 trapped Chilean miners who have astonished the world with their discipline a half mile underground will have to aid their own escape — clearing thousands of tons of rock that will fall as the rescue hole is drilled, the engineer in charge of drilling said Sunday.

After drilling three small bore holes in recent weeks to create lines of communication with the miners and deliver basic food and medicine, Chile’s state-owned Codelco mining company will begin boring a rescue hole this afternoon that will be wide enough to pull the men up through 2,300 feet of earth.

The first step will be to drill a “pilot hole” similar in size to the other three. Then much larger machine cutters will slowly grind through that hole, forcing crushed rock to fall down into the mine shaft area near the trapped men.