Why did the Chilean rescuers have to drill at 11º from vertical, then straight down?
Was there a mountain directly over the drift?
How do they change directions of the drill?
How does the design of the hammering drill they used differ from that of a well-drilling bit? Why can't a well drilling rig do the same job?
They said the trapped miners were ~1.5 miles down (~8000'). If the drift was say even 100' wide, this is very accurate mining engineering. The inventors of the rescue cage are in Pennsylvania. I assume they're the ones who supervised the rescue hole and rescue operation, with "helpful" oversight from the guvmint.