The Iron Mountain District, also known as the Iron Springs District, is a large, high-grade

iron Iron () is a chemical element with Symbol (chemistry), symbol Fe (from la, Wikt:ferrum, ferrum) and atomic number 26. It is a metal that belongs to the first transition series and group 8 element, group 8 of the periodic table. It is, Abundanc ...

depositBullock, K. C., 1970, Iron Deposits of Utah, Utah Geological and Mineral Survey Bulletin 88, 102 pgs. in southwestern

Utah Utah ( , ) is a state in the Mountain West subregion of the Western United States. Utah is a landlocked U.S. state bordered to its east by Colorado, to its northeast by Wyoming, to its north by Idaho, to its south by Arizona, and to it ...

, near

Cedar City Cedar City is the largest city in Iron County, Utah, United States. It is located south of Salt Lake City, and north of Las Vegas on Interstate 15. It is the home of Southern Utah University, the Utah Shakespeare Festival, the Utah Summer Gam ...

. It is currently in care and maintenance status (not actively producing iron ore) by CML Metals Corporation, a division of Palladon Ventures and Luxor Capital. Previous owners include

Geneva Steel Geneva Steel was a steel mill located in Vineyard, Utah, United States, founded during World War II to enhance national steel output. It operated from December 1944 to November 2001. Its unique name came from a resort that once operated nearby on ...

and U.S. Steel. The district is made of three primary

topographic Topography is the study of the forms and features of land surfaces. The topography of an area may refer to the land forms and features themselves, or a description or depiction in maps. Topography is a field of geoscience and planetary scien ...

highs along an approximately 17 mile

lineament ''See also Line (geometry)'' A lineament is a linear feature in a landscape which is an expression of an underlying geological structure such as a fault. Typically a lineament will appear as a fault-aligned valley, a series of fault or fold-ali ...

: Iron Mountain to the southwest, Granite Mountain in the middle, and The Three Peaks in the northwest. Mineralization in this district occurred as rings around the highs as a

skarn Skarns or tactites are hard, coarse-grained metamorphic rocks that form by a process called metasomatism. Skarns tend to be rich in calcium-magnesium-iron-manganese-aluminium silicate minerals, which are also referred to as calc-silicate mineral ...

, a replacement of existing

carbonate rock Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite (different crystal forms of CaCO3), and dolomite rock (also known as dolosto ...

material with high-grade iron ore, mostly in the form of high-grade (>50%Fe in places)

magnetite Magnetite is a mineral and one of the main iron ores, with the chemical formula Fe2+Fe3+2O4. It is one of the oxides of iron, and is ferrimagnetic; it is attracted to a magnet and can be magnetized to become a permanent magnet itself. With th ...

, but also locally hematite. Minor

pyrite The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Fe S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic luster and pale brass-yellow hue giv ...

is also present. Hot fluids are sourced from mid-

Tertiary Tertiary ( ) is a widely used but obsolete term for the geologic period from 66 million to 2.6 million years ago. The period began with the demise of the non-avian dinosaurs in the Cretaceous–Paleogene extinction event, at the start ...

intrusions, which core all three areas. Magnetite and hematite occur as replacements in the

Jurassic The Jurassic ( ) is a geologic period and stratigraphic system that spanned from the end of the Triassic Period million years ago (Mya) to the beginning of the Cretaceous Period, approximately Mya. The Jurassic constitutes the middle period of ...

limestone Limestone ( calcium carbonate ) is a type of carbonate sedimentary rock which is the main source of the material lime. It is composed mostly of the minerals calcite and aragonite, which are different crystal forms of . Limestone forms whe ...

around three

Laramide orogeny The Laramide orogeny was a time period of mountain building in western North America, which started in the Late Cretaceous, 70 to 80 million years ago, and ended 35 to 55 million years ago. The exact duration and ages of beginning and end of the ...

quartz monzonite Quartz monzonite is an intrusive, felsic, igneous rock that has an approximately equal proportion of orthoclase and plagioclase feldspars. It is typically a light colored phaneritic (coarse-grained) to porphyritic granitic rock. The plagiocl ...

porphyry,

laccolith A laccolith is a body of intrusive rock with a dome-shaped upper surface and a level base, fed by a conduit from below. A laccolith forms when magma (molten rock) rising through the Earth's crust begins to spread out horizontally, prying apar ...

intrusions. The iron ore was discovered by a

Mormon Mormons are a religious and cultural group related to Mormonism, the principal branch of the Latter Day Saint movement started by Joseph Smith in upstate New York during the 1820s. After Smith's death in 1844, the movement split into severa ...

scouting party in 1849, and furnaces were established in

in 1852, and then Old Irontown in 1868, to produce pig iron. Total production by 1965 from the district was 72,136,297 long tons of iron ore. Major areas of iron deposits and their associated mines/pits/ore bodies include: * Iron Mountain **Blowout **Blackhawk **Comstock **Mountain Lion **Tip Top **Pinto **Chesapeake **Excellsior ** Homestake * Granite Mountain **Desert Mound **Queen of the West *Three Peaks

References

External links

* Geography of Iron County, Utah Iron mines in the United States {{mining-stub