Someone needs to give the Guardian a Geology lesson... 6 miles is NOWHERE CLOSE to the center (or the centre) of the Earth!
BTDTGTTS :)
Many years ago there was a similar project, I forget by whom exactly, called Project Mohole. I have no idea what became of it. The name came from the 'Moho' (short for, I think, Mohorovicic Discontinuity), which is what the boundary between crust and mantle is called.