1964—Pub. L. 88–272 inserted “or domestic iron ore” in section catchline, and “or iron ore” wherever appearing in text.

Section 227(c) of Pub. L. 88–272 provided that: “The amendments made by this section [amending this section and sections 631, 1016, 1231, and 1402 and section 411 of Title 42, The Public Health and Welfare] shall apply with respect to amounts received or accrued in taxable years beginning after December 31, 1963, attributable to iron ore mined in such taxable years.”