The Earth Sciences Museum is temporarily closed until further notice. We apologize to all of our visitors and groups for this inconvenience. Thank you for your understanding. Back to Rocks and Minerals Articles. Copper, a soft red-coloured metal, was one of the first metals to be used in the ancient world. It has been exploited for at least years.
The name comes from the Greek word Kyprios , the name of the island of Cyprus in the Mediterranean Sea where copper occurs. Copper is an excellent conductor of heat and electricity and is found in most of the flexible cables used in the world. Its softness also makes it suitable for tubing for water pipes and central heating systems because it can be easily bent to fit around corners.
Above all, it can be mixed with other metals to make extremely useful alloys such as brass and bronze. Copper is a metal that has been deposited from hot sulphur solutions, created in volcanic regions. The hot solutions concentrated the copper up to a thousand times more than would normally be found in rocks. The resultant enriched rocks are called copper ores. Black fragments of shale still adhere to the copper. White Pine Mine was the last of the copper mines to close in northern Michigan in the In each case, the extraction of copper is of crucial importance to the country.
The amount of copper in the ground is relatively small and most of it occurs in low-grade ores that have to be processed twice to extract the copper. This is why it is important to reuse as much copper as possible, and why about one-third of copper consumed in most industrial countries is recycled from scrap. Copper can be found as a pure metal as well as in combination with other elements. There are over known copper minerals. Copper minerals are divided into five groups based on their chemistry.
Complex copper minerals —copper in combination with: iron, nickel, cobalt, lead, zinc or silver and other elements. Volcanogenic massive sulphide deposits are a major source of copper, zinc, lead, silver and gold.
Hydrothermal vents on spreading ocean bottom ridges, such as those found in the eastern Pacific Ocean, are actively precipitating metal sulphides. These deposits are formed by discharge of solutions into the seafloor. A Porphyry Copper Deposit derives its name from a porphyritic stock located at the center of the material deposit. In a porphyritic rock, some of the minerals are very large crystals up to 10 cm in length and the rest are microscopic.
Generally we find that the upper parts of the strato-volcano have been eroded away. The surrounding country rock, which has been intruded by the stock, is often metamorphosed by heat and pressure. During this metamorphism, sulphide minerals form in the rocks surrounding the stock. Heat and pressure causes pre-existing rocks to be altered into a new type of rock. An enriched mineral blanket or oxidized zone will then form near the surface of these deposits.
The porphyritic stock at the center of the system may not contain enough of the copper minerals to be an ore deposit. The rock that surrounds the stock however may be rich in copper mineralization.
The porphyritic stock is the engine that allows the development of the minerals. The ore minerals are found in a series of zones radiating outwards from the stock. Each of these zones contains a specific suite of minerals the minerals include azurite, malachite, gold, silver, chalcocite, and chalcopyrite.
The largest porphyry copper deposit of the Canadian Cordillera is approximately one billion tonnes with grades just under 0. Copper generally starts as chalcopyrite, a sulphide, which is then oxidized and enriched by interaction with the atmosphere, naturally acidic rainwater and nearby rocks and minerals. The top of an enriched copper deposit is a spongy mass of iron oxides left behind when iron sulphate and sulphuric acid are removed from sulphide minerals.
The liquid generated then converts the copper sulphides into copper sulphate, starting a chain reaction. As the copper sulphate solution trickles down through the unsaturated zone of the deposit where air and water are available the reaction continues.
The copper remained in the melt, 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. A mixture of copper, iron and sulfur is called chalcopyrite CuFeS 2 or 'fool's gold', and tricked many an old-time prospector! Chalcopyrite in Australia is found in rocks that are more than million years old. The sulfides, which yield most of the copper produced throughout the world, generally occupy the deeper parts of lodes which have not been exposed to weathering.
Near the surface they are altered by oxidation and other chemical actions to produce oxides and carbonates. These secondary copper minerals may form rich ore in the upper parts of many deposits, and owing to their characteristic green or blue colour, even small amounts are easily seen in the rocks in which they occur. Copper bearing minerals are commonly found in association with minerals which may contain gold, lead, zinc and silver.
In Australia, the search for copper began soon after European settlement. The first major discovery of copper in Australia was at Kapunda in South Australia in when Francis Dutton found copper ore whilst searching for lost sheep. By the s, South Australia was known as the 'Copper Kingdom' because it had some of the largest copper mines in the world.
We have several copper mines which are of world significance, including the Mt Isa copper-lead-zinc deposit in Queensland and the Olympic Dam copper-uranium-gold deposit in South Australia which is mining out one of the largest copper-bearing deposits in the world. Other examples of important copper resources are at the Prominent Hill and Carrapateena copper-gold deposits in South Australia, Northparkes copper-gold, CSA copper-lead-zinc and Girilambone copper deposits in New South Wales, the Ernest Henry, Osborne and Mammoth copper deposits and copper-gold deposits at Selwyn in Queensland and copper-zinc deposits at Golden Grove and the Nifty copper deposit in Western Australia.
Further resource and production information. Although large copper deposits are mined by open-cut methods in many of the major producing countries, most of the copper ore produced in Australia comes from underground mines.
The traditional method used at most mines involves the ore being broken and brought to the surface for crushing. The ore is then ground finely before the copper-bearing sulfide minerals are concentrated by a flotation process which separates the grains of ore mineral from the waste material, or gangue.
The concentrate is then processed in a smelter. At some Australian mines, the copper is leached from the ore to produce a copper-rich solution which is later treated to recover the copper metal.
The ore is first broken and set out on leach pads where it is dissolved by a sulfuric acid solution to leach out the copper. The copper-rich solution is then pumped to the solvent extraction plant to separate the copper as a copper complex. This is concentrated and the solution is passed to the electrowinning plant to recover the copper. The copper cathodes produced by electrowinning contain This entire process is known as solvent extraction electrowinning SX-EW. Various methods of smelting are used to convert the concentrates to copper metal.
The blister copper is tapped, further refined in an anode furnace and finally electrolytically refined to pure cathode copper. At Olympic Dam the concentrate is flash-smelted directly to blister copper. In this process copper concentrate is fed into the smelter with oxygen-enriched air.
The fine concentrate reacts or 'flashes' instantaneously as the sulfur fraction of the copper sulfides is burnt and becomes sulfur dioxide gas. Molten copper and slag fall to the hearth of the smelter. This rock is an ore of copper called chalcopyrite. It is one of the main ores of copper. The metal copper, separated from its ore, is widely used in the electrical industry. Gold has been used and treasured since the ancient civilizations of Ancient Egypt and Mesopotamia. Silver can be found in its pure form in volcanic rocks.
It is very shiny when polished, but soon tarnishes goes dull. Many household items like saucepans can be made out of iron.
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