Banded iron formations are distinctive units of sedimentary rock consisting of alternating layers of iron oxides and iron-poor chert. They can be up to several hundred meters in thickness and extend laterally for several hundred kilometers. Almost all of these formations are of Precambrian age and are thought to record the oxygenation of the Earth's oceans. Some of the Earth's oldest rock formations, which formed about 3,700 million years ago (Ma), are associated with banded iron formations.
Limonite is an iron ore consisting of a mixture of hydrated iron(III) oxide-hydroxides in varying composition. The generic formula is frequently written as FeO(OH)·nH2O, although this is not entirely accurate as the ratio of oxide to hydroxide can vary quite widely. Limonite is one of the three principal iron ores, the others being hematite and magnetite, and has been mined for the production of iron since at least 400 BC.
Iron ores are rocks and minerals from which metallic iron can be economically extracted. The ores are usually rich in iron oxides and vary in color from dark grey, bright yellow, or deep purple to rusty red. The iron is usually found in the form of magnetite (Fe
3O
4, 72.4% Fe), hematite (Fe
2O
3, 69.9% Fe), goethite (FeO(OH), 62.9% Fe), limonite (FeO(OH)·n(H2O), 55% Fe), or siderite (FeCO3, 48.2% Fe).
Pentlandite is an iron–nickel sulfide with the chemical formula (Fe,Ni)9S8. Pentlandite has a narrow variation range in nickel to iron ratios (Ni:Fe), but it is usually described as 1:1. In some cases, this ratio is skewed by the presence of pyrrhotite inclusions. It also contains minor cobalt, usually at low levels as a fraction of weight.
The Mesabi Iron Range is a mining district and mountain range in northeastern Minnesota following an elongate trend containing large deposits of iron ore. It is the largest of four major iron ranges in the region collectively known as the Iron Range of Minnesota. First described in 1866, it is the chief iron ore mining district in the United States. The district is located largely in Itasca and Saint Louis counties. It has been extensively worked since 1892, and has seen a transition from high-grade direct shipping ores through gravity concentrates to the current industry exclusively producing iron ore (taconite) pellets. Production has been dominantly controlled by vertically integrated steelmakers since 1901, and therefore is dictated largely by US ironmaking capacity and demand.
Godfrey is a small community located about 40 minutes' drive time north of Kingston, Ontario, Canada on Hwy. 38. It is named for Chester H. Godfrey, one of the original settlers, who donated land on which the village was built. While there is currently no specific village, it can be described as the area of Highway 38 that extends between the villages of Verona and Parham, as well as that portion of Westport Road extending to the hamlet of Burridge. It also includes the former settlement of Cole Lake.. Godfrey was originally in the Township of Hinchinbrooke which has since become amalgamated into the township of Central Frontenac, which also encompasses the townships of Kennebec, Olden and Oso.
Taconite is a variety of banded iron formation, an iron-bearing sedimentary rock, in which the iron minerals are interlayered with quartz, chert, or carbonate. The name taconyte was coined by Horace Vaughn Winchell (1865–1923) – son of Newton Horace Winchell, the Minnesota state geologist – during their pioneering investigations of the Precambrian Biwabik Iron Formation of northeastern Minnesota. He believed the sedimentary rock sequence hosting the iron-formation was correlative with the Taconic orogeny of New England, and referred to the unfamiliar and as-yet-unnamed iron-bearing rock as the 'taconic rock' or taconyte.
The Iron Range is collectively or individually a number of elongated iron-ore mining districts around Lake Superior in the United States and Canada. Much of the ore-bearing region lies alongside the range of granite hills formed by the Giants Range batholith. These cherty iron ore deposits are Precambrian in the Vermilion Range and middle Precambrian in the Mesabi and Cuyuna ranges, all in Minnesota. The Gogebic Range in Wisconsin and the Marquette Iron Range and Menominee Range in Michigan have similar characteristics and are of similar age. Natural ores and concentrates were produced from 1848 until the mid-1950s, when taconites and jaspers were concentrated and pelletized, and started to become the major source of iron production.
Ironsand, also known as iron-sand or iron sand, is a type of sand with heavy concentrations of iron. It is typically dark grey or blackish in color.
Sherman Mine is a closed open pit mine in Temagami, Ontario, Canada. It was a major producer of iron ore, starting production in 1968 and closing in 1990. Sherman was the largest open pit mine in Temagami, consisting of seven open pits known as the East Pit, South Pit, North Pit, West Pit and the Turtle Pits. The mine was discovered in the early part of the twentieth century, however interest was limited as a result of silver and gold discoveries in northeastern Ontario. While the Ontario government offered bounties to producers of iron ore, there was little interest in putting any iron mine into production as a result of cheaper Mesabi Range ores from the US and the Great Depression. It was only in the 1950s that Canadian steel producers started to investigate domestic supplies of iron ore. This would lead to the re-opening of the Moose Mountain Mine and development of the Adams, Sherman and Bruce Lake mines in Northern Ontario. The Sherman Mine operated in tandem with the Adams Mine in Kirkland Lake, and when the Adams Mine approached exhaustion of its economic ore reserves, the decision was made to also close the Sherman Mine. The surface infrastructure was removed and the site was abandoned. The waste piles are currently used by the municipality as a source of crushed stone for road works.
The Temagami Greenstone Belt (TGB) is a small 2.7 billion year old greenstone belt in the Temagami region of Northeastern Ontario, Canada. It represents a feature of the Superior craton, an ancient and stable part of the Earth's lithosphere that forms the core of the North American continent and Canadian Shield. The belt is composed of metamorphosed volcanic rocks that range in composition from basalt to rhyolite. These form the east-northeast trend of the belt and are overlain by metamorphosed sedimentary rocks. They were created during several volcanic episodes involving a variety of eruptive styles ranging from passive lava eruptions to viscous explosive eruptions.
The Buena Vista Mine is located 21 miles (34 km) southeast of Lovelock, Nevada. In the past, the area has been known as the Mineral Basin, though another name for the area has been the Buena Vista District. There are at least two other Buena Vista Mining Districts in Nevada; one is located near Unionville, Nevada, and the other is located in Esmeralda and Mineral counties near the California border. The nearby Buena Vista Hills are named for the mine. The district encompasses roughly 21 square miles (54 km2) of mineral and surface rights, and is one of the largest un-mined iron ore resources in the western United States.
The Animikie Group is a geologic group composed of sedimentary and metasedimentary rock, having been originally deposited between 2,500 and 1,800 million years ago during the Paleoproterozoic era, within the Animikie Basin. This group of formations is geographically divided into the Gunflint Range, the Mesabi and Vermilion ranges, and the Cuyuna Range. On the map, the Animikie Group is the dark gray northeast-trending belt which ranges from south-central Minnesota, U.S., up to Thunder Bay, Ontario, Canada. The Gunflint Iron Range is the linear black formation labeled G, the Mesabi Iron Range is the jagged black linear formation labeled F, and Cuyuna Iron Range is the two black spots labeled E. The gabbro of the Duluth Complex, intruded during the formation of the Midcontinent Rift, separates the Mesabi and Gunflint iron ranges; it is shown by the speckled area wrapping around the western end of Lake Superior.
Big Dan Mine is an abandoned underground mine in Northeastern Ontario, Canada. It is located about 1 km (0.62 mi) southwest of Net Lake and just west of the Ontario Northland Railway in east-central Strathy Township. It is named after Dan O'Connor, who first claimed the site in the 1890s.
The Kiruna mine is the largest and most modern underground iron ore mine in the world. The mine is located in Kiruna in Norrbotten County, Lapland, Sweden. The mine is owned by Luossavaara-Kiirunavaara AB (LKAB), a large Swedish mining company. In 2018 the mine produced 26.9 million tonnes of iron ore. The Kiruna mine has an ore body which is 4 km (2.5 mi) long, 80 metres (260 ft) to 120 metres (390 ft) thick and reaching a depth of up to 2 km (1.2 mi). Since mining began at the site in 1898, the mine has produced over 950 million tonnes of ore. As of 2020, the main haulage level is 1,365 m below the ore outcrop at Kiirunavaara that existed prior to mining.
Steep Rock Lake is a body of water near the township of Atikokan, northern Ontario, Canada. It was originally fed by the Seine River.
The Paulson Mine is a former iron ore mine located in Cook County, Minnesota, United States, 53 kilometres north-west of Grand Marais, Minnesota near the end of the historic Gunflint Trail. The Port Arthur, Duluth and Western Railway was built to the mine in 1892 to access the ore, but both the mine and railway failed.
El Laco is a volcanic complex in the Antofagasta Region of Chile. It is directly south of the Cordón de Puntas Negras volcanic chain. Part of the Central Volcanic Zone of the Andes, it is a group of seven stratovolcanoes and a caldera. It is about two million years old. The main summit of the volcano is a lava dome called Pico Laco, which is variously reported to be 5,325 metres (17,470 ft) or 5,472 metres (17,953 ft) high. The edifice has been affected by glaciation, and some reports indicate that it is still fumarolically active.
The Northeast Arm Iron Range, also called the Temagami Iron Range, is an elongated area of iron ore in Nipissing District of Northeastern Ontario, Canada. It parallels the western side of Lake Temagami's Northeast Arm near the village of Temagami at its northern end. One of many small iron ranges in the Temagami area, the Northeast Arm Range consists of alternating bands of iron-rich and iron-poor sediments. It was discovered in the 1890s and has since seen sporadic mining and mineral exploration activities.
Uranium mining around Bancroft, Ontario, was conducted at four sites, beginning in the early 1950s and concluding by 1982. Bancroft was one of two major uranium-producing areas in Ontario, and one of seven in Canada, all located along the edge of the Canadian Shield. In the context of mining, the "Bancroft area" includes Haliburton, Hastings, and Renfrew counties, and all areas between Minden and Lake Clear. Activity in the mid-1950s was described by engineer A. S. Bayne in a 1977 report as the "greatest uranium prospecting rush in the world".
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