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.
Along with launching exploration of the Bornite Deposit, the Red Dog Mine continues to be one of the world's most significant producers of zinc and employs a significant number of NANA shareholders as part of the operator's agreement with the Alaska Native Corporation.
South32's initial funding of $10 million for Trilogy projects in 2017 is being spent on exploration at the Bornite project to test the extension of high-grade copper at the deposit.
Chalcopyrite also occurs as overgrowths on bornite and infrequently as crystals and small masses within calcite veins.
Gunung Bijih Timor (Indonesian for "Ore Mountain East") is bornite dominant, followed by chalcocite, chalcopyrite, digenite, minor electrum, and minor native gold.
The Upper Kobuk Mineral Projects consist of the Arctic deposit located on state of Alaska mining claims owned by NovaCopper and the Bornite deposit located sixteen miles southwest of the Arctic deposit on NANA-owned lands.
Malachite and azurite, along with primary hypogene chalcocite and the presence of bornite and chalcopyrite, have been identified at depths of at least 100 m.
The AMDIAR is anticipated to provide access to the Ambler mining district and our UKMP Projects - Arctic and Bornite.
Proceeds will be used by the company to carry out a modest field programme that will primarily consist of re-logging and re-assaying historical drill holes at Bornite which were previously drilled and only selectively sampled.
Mineralisation at the Attunga Copper Mine is interpreted to be sub-vertical and occurs in garnet-rich calc-silicate skarn with sulphide minerals including chalcopyrite, bornite and molybdenite.
Today the Butte mines are closed and flooded, but its mineralogical legacy of fine specimens remains--most noteably the copper sulfide and sulfosalt minerals such as bornite, chalcocite, chalcopyrite, colusite, covellite, digenite, djurleite, and enargite, and other minerals such as barite, pyrite, quartz and silver.
Preparations were underway to make the Bornite camp fully operational by mid-July with drilling activities expected to be completed by September.