IRON ORE DEPOSITS
IRON ORE DEPOSITS. Iron ore deposits of two kinds occur in Texas in two general areas: magnetic iron ores in the central mineral region and brown ores (limonite, goethite, and hematite) in northeastern Texas. Iron is found in considerable quantities in the area of Burnet, Llano, and Gillespie counties, the most notable deposit being that at Iron Mountain in Llano County. These ores are hematite and magnetite magnetic black iron oxide. There have been some shipments from this deposit. In East Texas both siderite (iron carbonate) and limonite (iron oxide) exist in large quantities, primarily in Anderson, Cass, Cherokee, Harrison, Henderson, Houston, Leon, Marion, Morris, Nacogdoches, Smith, Upshur, Van Zandt, and Wood counties, where the ore deposits occur usually in strata forming the caprocks of low mountain ranges. Although the amount of ore in Texas is known to be great, no definite estimate of tonnage can be made. Extensive deposits of glauconite (a complex silicate containing iron) that occur in East Texas and the hematitic and goethitic Cambrian sandstone that crops out in the northwestern Llano Uplift region are potential sources of low-grade iron ore. Used earlier by the iron and steel industry, limonite and other East Texas iron ores have more recently been mined for use in preparing portland cement, as a weighing agent in well-drilling fluids, and in animal-feed supplements. When iron production virtually ceased in 1910, less than 700,000 long tons of ore had been processed. The World War II demand for iron and steel stimulated production; small amounts of ore were mined until 1943, when more modern plants were constructed and production revived. According to the United States Bureau of Mines, in 1947 Texas processed 289,273 long tons of ore, and by 1950 Texas ores were being utilized in larger quantities.
In the 1970s the Lone Star and Tex-Iron plants recovered ore from open-pit mines in Cass, Morris, and Nacogdoches counties in the northeastern part of the state to produce pig iron and cement. Significant amounts of iron ore were received and shipped both overseas and domestically during the decade. In 1975 production totaled 601,000 long tons, and in 1979 Texas exported 346 short tons of iron ore to foreign countries and 8,356 short tons domestically. Reflecting a strong energy-related demand for steel products, iron ore output in 1980 rose about 17 percent and increased in unit value per ton. In that year Texas ranked eighth among twelve iron-ore-producing states and shipped 262 short tons. Limonite and siderite ores were recovered from open-pit mines in Cass, Cherokee, Henderson, and Morris counties. In 1985 Texas exported 1,116 short tons of iron ore to foreign countries and 22,237 short tons domestically, in addition to receiving significant imports. The last mining of iron ore for metal manufacture ceased in the mid-1980s, when Lone Star Steel terminated work at its Cass County mine. Primary smelters, refineries, and ore-reduction plants included those of Armco, Lone Star, and U.S. Steel. In the 1990s Mathis and Mathis Mining and Exploration Company and Hudson Brothers Company mined ore for nonmetal markets. Mathis and Mathis sold siderite from a mine in Cass County for use in animal-feed manufacture, while Hudson Brothers produced siderite and limonite for use in cement manufacture at its Cherokee County mine. Low-grade ore was used for highway aggregate. See also IRON AND STEEL INDUSTRY.
University of Texas, Texas Looks Ahead: The Resources of Texas (Austin, 1944; rpt., Freeport, New York: Books for Libraries Press, 1968). U.S. Bureau of Mines, Minerals Yearbook.