Nah. Case the hole and backfill it with mortar. cheap, effective, and permanent. If it is welling up from the bottom, you're screwed anyway, but otherwise, the casement fixes it... at least to the point that a pump can keep up with it.
Cryo... Freezing? I would think that would be extremely expensive to maintain.
Problem is the money pit is already cased with a decades old steel. They sent two sets of divers down with various problems resulting