The locators of all mining locations heretofore made or hereafter made under the provisions of RCW 78.08.005 through 78.08.040, on any mineral vein, lode or ledge on the public domain, and their heirs and assigns so long as they comply with the laws of the United States and the state and local laws relating thereto, shall have the exclusive right to the possession and enjoyment of all surface included within the lines of their location, and of all veins, lodes and ledges throughout their entire depth, and the top or apex of which lies within the surface lines of such location, extending downward vertically, although such veins, lodes or ledges may so far depart from the perpendicular in their course downward as to extend outside of the vertical side line of said surface location.