The question of the extra-lateral rights of a locator has been thus summarized by the Supreme Court of the United States in the case of Del Monte Min., etc., Co. vs. Last Chance Min. Co.3

"Our conclusions may be summed up in these propositions: First, the location as made on the surface by the locator determines the extent of rights below the surface. Second, the end lines, as he marks them on the surface, with the single exception hereinafter noticed, place the limits beyond which he may not go in the appropriation of any vein or veins along their course or strike. Third, every vein, the top or apex of which lies inside of such surface lines extended downward vertically becomes his by virtue of his location, and he may pursue it to any depth beyond his vertical side lines, although in so doing, he enters beneath the surface of some other proprietor. Fourth, the only exception to the rule that the end lines of the location as the locator places them establish the limits beyond which he may not go in the appropriation of a vein on its course or strike is where it is developed that in fact the location has been placed not along, but across the course of the vein. In such case, the law declares that those which the locator called his side lines are his end lines, and those which he called end lines are in fact side lines, and this upon the proposition that it was the intent of Congress to give to the locator only so many feet of the length of the vein, that length to be bounded by the lines which the locator has established of his location."

The surface lines extended downward vertically determine the extent of the claim, except when in its descent, the vein passes outside of the line, and the outside portions are to lie between vertical places drawn downward through the end lines. This means the end lines of the surface location, for all locations are measured on the surface. ' The difficulty arising from the section grows out of its application to claims where the course of the vein is so variant from a straight line that the end fines of the surface location are not parallel, or, if so, are not at a right angle to the course of the vein. This difficulty must often occur where the lines of the surface location are made to control the direction of the vertical planes. The remedy must be found, until the statute is changed, in carefully making the location, and in postponing the marking of its boundaries until explorations can be made to ascertain, as near as possible, the course and direction of the vein. In Colorado, the statutes allow for this purpose sixty days after notice of the discovery of the lode. Then the location must be distinctly marked on the ground, and thirty days thereafter are given for the preparation of the proper certificate of location to be recorded. Even then, with all the care possible, the end lines marked on the surface will often vary greatly from a right angle to the true course of the vein. But whatever inconvenience or hardship may thus happen, it is better that the boundary planes should be definitely determined by the lines of the surface location, than that they should be subject to perpetual readjustment according to subterranean developments made by mine workings. Such readjustment at every discovery of a change in the course of the vein would create great uncertainty in titles to mining claims. The rule, whatever hardship it may work in particular cases, should be settled, and thus prevent, as far as practicable, such uncertainty." 4

3 171 U. 8., 89.

4 Iron Silver Min. Co. vs. Elgin Min., etc. (1886), 118 U. S., 206; Fitzgerald vs. Clark (1895) 17 Mont., 100.

When the owner is in possession of the surface and apex of a vein, he must be deemed to be in possession of all parts of the vein to which he has title, though it departs beyond his side lines, just as he is in possession of that portion of the earth vertically beneath his surface, and when he has followed it, he commits no wrong and is not a trespasser.5