Any opencut, crosscut, or tunnel at a depth sufficient to disclose the mineral vein or lode, an adit of at least ten feet [3.05 meters] in along the lode from the point where the lode may be discovered, or the drilling of a hole or holes in the manner, and under the conditions and requirements hereinafter set forth, is equivalent to a discovery shaft. The hole or holes must be not less than one and one-half inches [3.81 centimeters] in diameter, must be sufficiently deep to reach and cut or expose the mineral vein or lode, and must be protected at the surface opening against injury to livestock. The discoverer shall designate one of the holes thus drilled as the discovery hole, in the event that more than one such hole has been drilled.