State Symbols of Utah: Copper, Utah's State Mineral
Copper is the oldest metal known to mankind. Archaeologists discovered a copper pendant in what is now northern Iraq that dates back to about 8700 B.C. The Egyptians and Sumerians were the first known to employ the science of metallurgy or reducing ores with fire and charcoal. Copper tubing that was used as part of a water plumbing system in the Pyramid of Cheops in Egypt in ancient times has been discovered that is still in useable condition after more than 5,000 years.
About 3500 B.C. copper was alloyed (melted together) with tin to make bronze. This metal was so widely used during this time that it is called the Bronze Age.
Columbus used copper sheathing below the water line on his ships when he set sail for America. Copper was chosen in order to extend the life of the ships' hulls and to protect the ships against barnacles and other kinds of ocean hazards. Paul Revere used copper extensively, in producing bronze cannons, spikes and pumps for Old Ironsides, the famous Revolutionary War ship. Today a whole line of cookware with copper bottoms is known as RevereWare.
Copper is a reddish chemical element but many of the minerals associated with it are green in color. It is known for its ability to conduct heat and electricity. It is widely used in electronics, plumbing, transportation and is often mixed with other metals into combinations known as alloys. There are more than 50 lbs. of copper in an automobile manufactured in the U.S. A Boeing 747-200 jet plane has more than 9000 lbs. of copper in its frame.
The Statue of Liberty contains 179,000 lbs. of copper!
Copper and other ores are removed from the ground by open-pit or underground mining. Chile has been the world's largest producer of copper for many years with the U.S. running a close second. In Utah we have the largest open-pit copper mine in the world, Kennecott's Bingham Canyon mine. It is located in the Oquirrh Mountains on the west side of Salt Lake Valley. This mine has produced over 12 million tons of copper since it began operations in 1906. That's eight times more mined metal than the Comstock Lode, Klondike and California Gold Rushes combined!
In order to have profitable production, an open-pit mine needs to contain at least 4% copper ore while an underground mine must have at least 6-7%.
There are many copper-bearing ores. They fall into two main categories: oxidized ores and sulfide ores.
The oxidized ores, such as cuprite and tenorite,, can be reduced into metallic copper simply by heating them with carbon in a furnace. The sulfide ores, such as chalcopyrite and chalcocite, require a more complex treatment. They require the addition of other low-grade ores before the smelting process begins. Commercially the most important ores are the sulfide ores. Chalcopyrite accounts for half of the world's copper deposits.
Important alloys in which copper makes up the greatest part are the brasses (copper w/zinc), the bronzes (copper w/tin) and the nickel silvers (copper w/zinc & nickel). Copper coinage has been used throughout the ages until the 1960's when aluminum surpassed it (due to being cheaper and more plentiful).
A trace of copper is an important element in the health of most plants and animals. It is used in the oxidating process.
"A trace of copper each day keeps nature in sway!"
Copper is an easily worked metal. It can be cold-rolled down to 1/1000th inch and stretched by cold-drawing 5,000 times its natural length. This makes it ideal for making wire. Copper is also a beautiful mineral when used in jewelry or for other ornamental purposes.