In mining law. The right of the owner of a mining claim duly located on the public domain to follow, and mine, any vein or lode the apex of which lies within the boundaries of his location on the surface, notwithstanding the course of the vein on its dip or downward direction may so far depart from the perpendicular as to extend beyond the planes which would be formed by the vertical extension downwards of the side lines of his location. See Rev. Stat U. S. f 2322 (U. S. Comp. St 1901, p. 1425).