The severance tax on uranium is measured by the quantity of U3O8 contained in and recoverable from severed and saved uranium-bearing material whether that material is ore or solution, measured in a standard manner established by regulation of the director. The taxable event is the sale, transportation out of New Mexico or consumption of the uranium-bearing material, whichever first occurs. Upon each pound of severed and saved U3O8 contained in severed uranium-bearing material, there shall be collected from the severer a severance tax equal to three and one-half percent of taxable value.