|Copper can be found as native copper in mineral form. Minerals such as the sulfides: chalcopyrite (CuFeS2), bornite (Cu5FeS4), covellite (CuS), chalcocite (Cu2S) are sources of copper, as are the carbonates: azurite (Cu3(CO3)2(OH)2) and malachite (Cu2CO3(OH)2) and the oxide: cuprite (Cu2O).
Most copper ore is mined or extracted as copper sulfides from large open pit mines in porphyry copper deposits that contain 0.4 to 1.0 percent copper. Examples include: Chuquicamata in Chile and El Chino Mine in New Mexico. The average abundance of copper found within crustal rocks is approximately 68 ppm by mass, and 22 ppm by atoms.The Bingham Canyon Mine, in the Salt Lake Valley, Utah, is the worlds largest open pit mine. It is one of only two man made stuctures visable from space, after the Great Wall Of China. It is owned by Kennecott Mining Company, and is primarily used for the mining of copper. In 2005, Chile was the top mine producer of copper with at least one-third world share followed by the USA, Indonesia and Peru.
|The formation of CopperBecause copper reacts readily with other substances, it can be found in a variety of ways in the Earth’s crust. It is often found in deposits with other metals such as lead, zinc, gold and silver.
By far the largest amounts of copper are found in the crust in bodies known as porphyry copper deposits. These deposits were once large masses of molten rock that cooled and solidified deep in the Earth’s crust. As they cooled, some large crystals grew, which were then surrounded by smaller crystals – geologists call these rocks porphyries.
|At first, the molten rock contained a small amount of copper. As it cooled and crystals began to form the amount of fluid became smaller. The copper remained in the fluid, becoming more and more concentrated. When the rock was almost completely solid, it contracted and cracked and the remaining copper-rich fluid was squeezed into the cracks, where it too finally solidified. Over many millions of years the rocks covering these deposits eroded away and the deposits eventually appeared at the surface. These deposits can contain 2 billion tonnes of rock which, when processed, gives 30 million tonnes of copper metal.|
|The properties of Copper
The word copper comes from the Latin word “cuprum”, which means “ore of Cyprus”. This is why the chemical symbol for copper is Cu.Copper is the only naturally occurring metal other than gold that has a distinctive colour. Like gold, copper is an excellent conductor of heat and electricity. It is also very malleable and ductile.
Copper is easily mixed with other metals to form alloys such as bronze and brass. Bronze is an alloy of tin and copper, and brass is an alloy of zinc and copper.
Copper is also resistant to corrosion (it does not rust very easily).
|COPPER RESOURCES OF INDIA|
|Copper mining is constrained by the lack of good quality ore and average metal content in Indian ore is 1 per cent against the world average of 1.5 per cent. India has an estimated copper resource of 730 Mt averaging 1.17% copper.
Out of this, only 185 Mt of ore with an average grade of 1.21% copper is under mining lease held by state controlled Hindustan Copper Limited. Until 1998, Hindustan has been the only producer of copper concentrate in India. Since then, several smaller companies, including Sikkim Mining Corporation at Rangpo and Hutti Gold Mines in Karnataka have been producing concentrates. Hindustan Copper will now be largely relying on its Malanjkhand mines at Madhya Pradesh, which has grades of 1.42 % copper.Hindustan Copper limited is sole producer of copper from mines.India is not a significant contributor either in copper mining or in smelting. According to the National Mineral Inventory, as on 1.4.2005 (provisional) the total resources are placed at 1394 million tonnes with a metal content of 11.41 million tonnes. At present demand of copper ore for primary copper production is met through two sources viz., copper ore mined from indigenous mines and imported concentrate produced from copper ores mined elsewhere in the world. The indigenous mining activity is limited to HCL while private sector i.e. M/s Birla Copper and M/s Sterlite Industries produce copper metal from imported concentrate through their share based smelter plants.
Copper deposits in India are localized mainly in the Precambrian terrains of the Peninsular Shield and to small extent in the lesser Himalayas. The three prominent belts, where copper deposits are located include Singhbhum Copper Belt (SCB), Khetri Copper Belt and Malanjkhand Copper Belt. Under Singhbhum Copper Belt, the Turamdih cluster of deposits consisting of five prospects viz. Turamdih, Dhadkidih, Nandup, Bayanbil and Ramchandrapahar extending over a strike length of 5 km hold potential for cluster mining through open cast method after detailed exploration by MECL. The Chapri- Siddheswar deposits of central part of SCB deserve attention for exploitation as Chapri block with a combination of wide ore zone and high tonnage hold potential for open cast mining while Siddheswar having narrow zone with rich copper ore bodies can be thought for underground mining in near future. The Khetri Copper belt has significant copper deposits at Khetri, Kolihan, Chandmari, Banwas, Singhana etc. Two mines viz. Khetri and Kolihan mines of HCL are producing copper ore at present.