Data Beginning 1906 Exclude Ore Containing More Than Five Percent Manganese. Data Available For 1860, 1870, 1875, And 1880-1888 Pig Iron Production. Source: U.S. Bureau Of The Mines, Mineral Resources; Minerals Yearbook.
This NBER data series a01238 appears on the NBER website in Chapter 1 at http://www.nber.org/databases/macrohistory/contents/chapter01.html.
NBER Indicator: a01238
Release: NBER Macrohistory Database
National Bureau of Economic Research, Iron Ore Production for United States [A01238USA576NNBR], retrieved from FRED, Federal Reserve Bank of St. Louis https://research.stlouisfed.org/fred2/series/A01238USA576NNBR/, September 3, 2015.