The use of copper in antiquity is of more significance than gold as the first tools, implements and weapons were made from copper. From 4,000 to 6,000 BC was the Chalcolithic period which was when copper came into common use. The symbol for copper is Cu and comes from the latin cuprum meaning from the island of Cyprus. Initially copper was chipped into small pieces from the main mass. The small pieces were hammered and ground in a manner similar to the techniques used for bones and stones. However, when copper was hammered it became brittle and would easily break. The solution to this problem was to anneal the copper. This discovery was probably made when pieces were dropped in camp fires and then hammered. By 5,000 BC copper sheet was being made.
By 3600 BC the first copper smelted artifacts were found in the Nile valley and copper rings, bracelets, chisels were found. By 3000 BC weapons, tools etc. were widely found. Tools and weapons of utilitarian value were now within society, however, only kings and royalty had such tools; it would take another 500 years before they reached the peasants.
Malachite, a green friable stone, was the source of copper in the early smelters. Originally it was thought that the smelting of copper was by chance dropping of malachite into campfires. However, campfire temperatures are normally in the region of 600-650 C, whereas, 700-800 C is necessary for reduction. It is more probable that early copper smelting was discovered by ancient potters whose clay firing furnaces could reach temperatures of 1100-1200 C. If Malachite was added to these furnaces copper nodules would easily be found. Although the first smelted copper was found in the Nile valley, it is thought that this copper was brought to Egypt by the Gerzeans and copper smelting was produced first in Western Asia between 4000 and 4300 BC.
Although copper can be found free in nature the most important sources are the minerals cuprite, malachite, azurite, chalcopyrite and bornite. Copper is reddish colored, malleable, ductile and a good conductor of heat and electricity. Approximately 90% 0f the worlds primary copper originates in sulfide ores.
Copper is a metal that can be readily stretched, molded and shaped. It is resistant to corrosion and has a very high thermal and electrical conductivity. It is also one of only a few metals that have these properties and occurs abundantly in nature. The metal and its alloys have been in use for over 10,000 years. Copper can be found as either native copper or as part of minerals such as chalcopyrite and chalcocite (copper sulfides), azurite and malachite (copper carbonates) and cuprite (copper oxide).
Where Copper is Found
Copper is found naturally throughout the world in the Earth’s crust. It is most commonly found in deposits with other metals such as nickel, zinc, gold, silver and molybdenum. The largest amounts of low-grade copper-bearing material are found in porphyry copper deposits. Most copper is mined or extracted as either copper sulfides or oxides from large open pit mines in porphyry copper deposits that contain 0.4 to 1.0% copper. Examples include Chuquicamata in Chile, Bingham Canyon Mine in Utah, and the Phelps Dodge Morenci mine in Arizona.
Stages of Copper Mining
The first stage in copper mining is distinguishing between ore and overburden. Ore is defined as material that can be economically mined; whereas overburden (often referred to as waste) is non-economic material overlaying or intermixed with the ore. All material is first drilled and blasted and the ore is taken to a concentrator for processing. At the concentrator, the ore is crushed and then ground to the consistency of ladies’ face powder. Following the grinding circuit, the ore (now a slurry) is sent to flotation. In the flotation section, the ore and compressed air are introduced at the bottom of large tanks and combined with reagents (mostly soaps and pine oils). These reagents have an affinity for copper and when combined with the compressed air create a froth of bubbles. The copper (and other metals) sticks to the bubbles and ‘floats’ to the surface and is skimmed off. The next step involves a mechanical thickener which separates the water from the skimmed bubbles (ore). The water then re-circulates into the grinding sections and the bubbles (now called concentrate) are sent to a filter plant where more water is removed and recycled. This step is repeated to recover as much copper as possible. The final stage is delivering waste material, called tailings, to a lined storage facility. Here, more water is reclaimed and cycled back to the milling process. The concentrate is then shipped to either a smelter or refinery for further processing.
Common Uses of Copper
Approximately 65 percent of copper produced is for electrical purposes, including power generation and transmission. Copper is also commonly used in construction for plumbing, roofing, shipbuilding, industrial engines, as well as cars, trains and trams. The average car contains almost one mile of copper wire; total copper ranges from 44 pounds in small cars to 99 pounds in larger vehicles; and a hybrid vehicle uses about twice the copper of a regular internal combustion engine. The typical average American uses 935 pounds of copper in his or her lifetime.
Copper Production in Arizona
Arizona's economy gained almost $9.3 billion and 52,500 Arizona residents had jobs in 2009 as a result of the combined direct and indirect contributions of the copper industry to personal, business and government income in the state.
Looking at the combined direct and indirect impact of almost $9.3 billion in 2009, $2.6 billion in personal income; $6.2 billion in business sales and $468 million in state and local government revenues.
Copper producers who have active mineral production in Arizona are ASARCO LLC, BHP Copper Inc., Freeport-McMoRan Copper & Gold Inc., Carlota Copper Co., Nord Resources, and Mercator Minerals.
Copper Market Overview
- Macro-economic factors influencing investor sentiment and financial markets
- Physical markets remain relatively tight
- Supply side constraints continue
- Expect near-term volatility
- Positive medium/long-term outlook
- Short term macroeconomic concerns regarding the US and Europe. Together, they represent almost 50% of the world economy and 31% of copper demand.
- However, fundamentals are excellent for copper:
- Asia represents over 60% of world demand (China=37%)
- China’s monetary tightening should not derail the country’s sustained growth and copper demand.
- Limited production upside and falling grades result in a deficit market going forward.
- Possible 2011 deficit of 400K
Copper Consumption by End-Use
Copper Consumption by Region