In mining law. The right of the owner of a mining claim dulylocated on the public domain to follow, and mine, any vein or lode the apex of whichlies within the boundaries of his location on the surface, notwithstanding the course ofthe vein on its dip or downward direction may so far depart from the perpendicular asto extend beyond the planes which would be formed by the vertical extensiondownwards of the side lines of his location. See Rev. Stat. U. S.