Bornite


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Related to Bornite: chalcocite, Enargite, covellite

bornite

[′bȯr‚nīt]
(mineralogy)
Cu5FeS4 A primary mineral in many copper ore deposits; specific gravity 5.07; the metallic and brassy color of a fresh surface rapidly tarnishes upon exposure to air to an iridescent purple.

Bornite

 

(named after the Austrian metallurgist and mineralogist I. Born, 1742–91), a mottled copper ore, a mineral and a sulfide of copper and iron corresponding to the formula CusFeS4. It contains 52–65 percent copper and 8–12 percent iron. It crystallizes into a cubic system; a modification of a rhombic system is known. Its crystalline structure is of the spinel type. Crystals (cubic or dodecahedral habits) are rare; dense grainy masses are common. They are dark colored, copper red, usually with bright mottled oxide tint in old fractures. Its hardness on the mineralogical scale is 3, and its density is 4,900–5,300 kg/m3.

Bornite is of varying origin. As a hypogene mineral, it is formed in various types of hypothermal deposits. During supergene processes, it is formed in the zone of secondary sulfide concentration. Evolutions of supergene bornite are found in sedimentary rocks, sometimes in the form of pseudomorphoses by organic residues. In hydrothermal deposits, bornite usually is found in association with chalcopy-rite, pyrite, sphalerite, and fahlerz (gray copper ore). It is observed rather frequently in deposits of the type of pyrite seams. Malachite, azurite, cuprite, and other minerals are formed from bornite in oxidation zones. Bornite is an important mineral of copper ores. Deposits of bornite in the USSR are found in the Urals, in the Caucasus, and in Kazakhstan; they are found abroad in the USA, Yugoslavia, South West Africa, and the German Democratic Republic.

References in periodicals archive ?
Assays indicate the copper mineralisation, and in particular the bornite veins, have a high silver content.
Bornite has big potential--an additional copper resource was discovered there in recent years--but it will need additional exploration.
In the first half of 2014, we were engaged in the update to the Bornite Project resource estimate, a report involving technical and engineering consulting; no comparable expenditure was incurred in 2015.
A major hurdle to mine development is the remoteness of the Ambler Mining District, a seventy-five-mile-long band of mineralization that encompasses the Arctic and Bornite sites, as well as many other mineral deposits.
The Company also plans to advance assessment work at Bornite; specifically to evaluate potential synergies between the Arctic and Bornite Projects.
While the average grade at Bornite is lower on average, it also is a large resource with two distinct zones, South Reef and Ruby Creek.
The Northwest Zone is a northwest trending, steeply to sub-vertical northeast dipping zone containing disseminated, fracture and vein controlled native copper, chalcocite, bornite, chalcopyrite and malachite mineralisation.
The combination of NovaCopper and Sunward will create a leading exploration and development company with a strong balance sheet of approximately US$23 million in cash for the advancement of the Arctic and Bornite deposits located in the Ambler mining district of Alaska, USA.
The principle ore minerals are bornite and chalcopyrite and samples of the high-grade mineralisation zones identified in OUDDH015 are shown in Figures 5a, 5b & 5c.
Westernmost mineralisation generally lacks magnetite but contains bornite as well as chalcopyrite.
Copper, with grades shown in Table 2, is mainly contained in chalcopyrite, bornite, chalcocite, and copper carbonates in the oxide zone.
For the comparable period in 2014, we were engaged in the update to the Bornite Project resource estimate involving technical and engineering consulting for which there are no comparable costs in the first quarter of 2015.