I've been mulling over the problem of unbalancing the Universe if we bring the stuff to the surface, and I think I've got the solution. Have the diggers bring up small quantities, and if they start to feel the planet tipping or anything, they can discard some as they come up. Maybe they should bring parakeets down with them, just in case.
Dig two shafts 180
o apart. By coordinating the recovery effort balance can be maintained.
Aslan is not a
Tame Lion