At the bottom of the Knotty Head hole, the 450-degree-Fahrenheit temperature and the pressure (2, 000 times atmospheric) would crush or melt most drilling tools.

FORBES: Magazine Article

Another point worth making is that not everyone who hits the donut hole does so to a significant degree.

FORBES: Move up http://i.forbesimg.com t Move down

Under Plan B, a hole is being drilled at a roughly 80-degree angle into an area of the mine shaft that is used as a mechanical workshop.

CNN: STORY HIGHLIGHTS