329. Right to withdraw support.

If it is intended that the lessee is to be entitled to work so as to withdraw support from the surface, the lease should grant express liberty so to work1. The mere fact of giving a right to sink pits and to work and get minerals is not sufficient to deprive the surface owner of his common law right of support2. To displace this common law right permission to withdraw support must be given expressly or by necessary implication3. Cases of express permission present no difficulty; but the question whether or not permission is given by implication must be