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In the classic gossan or iron cap all that remains is iron oxides and quartz, often in the form of boxworks (which are quartz-lined cavities retaining the shape of the dissolved ore minerals). In other cases, quartz and iron oxides, limonite , goethite , and jarosite , exist as pseudomorphs, replacing the pyrite and primary ore minerals.
Iron oxide copper gold (IOCG) deposits are considered to be metasomatic expressions of large crustal-scale alteration events driven by intrusive activity. The deposit type was first recognised by discovery and study of the supergiant Olympic Dam copper-gold-uranium deposit (Olympic Dam mine), and South American examples.
The 1,045 metres (3,428 ft) level could support iron ore production until 2018. On October 28, 2008 LKAB decided to go even deeper, with the mine reaching a depth of 1,365 metres (4,478 ft) by 2012 at a cost of US$1.7 billion. [1] Cross section of Kiruna iron ore mine
Elemental iron is virtually absent on the Earth's surface except as iron-nickel alloys from meteorites and very rare forms of deep mantle xenoliths.Although iron is the fourth most abundant element in Earth's crust, composing about 5% by weight, [4] the vast majority is bound in silicate or, more rarely, carbonate minerals, and smelting pure iron from these minerals would require a prohibitive ...
The area is known for its extensive deposits of gold, diamonds, and iron ore, being the source of approximately 40% of all gold produced in Brazil between the years 1500 and 2000. The deposits themselves pertain to the Minas Supergroup , a sequence of meta-sedimentary rocks initially formed in the Paleoproterozoic , about 2.5 Ga.
Burt's solar compass or astronomical compass/sun compass is a surveying instrument that makes use of the Sun's direction instead of magnetism. William Austin Burt invented his solar compass in 1835. The solar compass works on the principle that the direction to the Sun at a specified time can be calculated if the position of the observer on the ...
The team discovered that there was likely a fire that destroyed a portion of the temple, which led to brick partitions being put in place to protect the remaining sections, and to a new section ...
The Sun is the star at the center of the Solar System.It is a massive, nearly perfect sphere of hot plasma, heated to incandescence by nuclear fusion reactions in its core, radiating the energy from its surface mainly as visible light and infrared radiation with 10% at ultraviolet energies.