Copper Mining in Arizona

Arizona is just beautiful - even when it's being open-pit mined!  Arizona got it's name from a silver mine, the Arizonac, southeast of Nogales.  I hope you're sitting down to hear this, because that mine revealed silver nuggets weighing over a ton!  That's a jaw-dropper for sure!

The Summit open-pit mine near Payson, Arizona is a copper mine, but most of today's silver comes as a byproduct of copper processing, and Arizona is first in the nation for copper production and only fifth in the nation for the production of silver. 

The first copper mine in America was opened in Branby, Connecticut, in 1705, followed by one in Lancaster, Pennsylvania, in 1732.  By the 1840's, miners in Michigan were finding massive chunks of "float" copper weighing up to 1,000 tons!  These were torn off from rock by glaciers and "floated" in or on those glaciers to their present locations.   Back then, of course, there were no electronics, and copper was used mainly in making coins, cooking pots and as a sheathing on the bottom of ocean-going wooden ships.  It was also mixed with other metals to be used as bell metal and gun metal. Copper mining back east has pretty well wrapped up because they were doing deep shaft mining, and places like Arizona could do open-pit mining which was a way less expensive (and safer) way to get at the minerals.  Today the top five copper-producing states are Arizona, Utah, New Mexico, Nevada and Montana with minor production coming from Alaska, Idaho and Missouri.

Edison's invention of the electric light in the 1870s created the use of copper in the electrical industry.

Woo-hoo!  The price for copper has increased from an average of $0.76 per pound in 2002, to $3.18 per pound today. 

The Summit

The Morenci open pit complex in Arizona is the largest copper mine in North America.

The Summit

Back in the day of black powder mining, miners staggered the timing of their explosions so they could listen to be sure all the holes had fired.  Black powder was sorta unstable and the charges didn't necessarily always go off as timed.  By the 1880's dynamite had replaced black powder charges.

I suppose the multitude of colors means a multitude of minerals, eh?  Copper isn't ordinarily found all by itself.  It is usually chemically bonded with other things like sulfur, gold, silver, nickel, etc.  They use the colors of other minerals to "name" the copper ore:  Copper pyrite is yellow in appearance, cuprite copper is red, malachite is green, azurite is blue... 

Once excavated from the open pit mine it goes through a process to "concentrate" it, sometimes onsite and sometimes at a processing plant.  It is crushed into smaller chunks and then going first through a rod mill and then a ball mill which takes it down to .01 inch diameter.  That stuff is mixed with a slurry of chemicals that attach to the copper particles.  Pine-oil or long-chain alcohol is added as a "frother" and the copper clings to the bubbles as they rise to the surface.  The frother causes the slurry to overflow the tanks and the thick layer of bubbles that has formed on the top is pour into troughs.  Eventually the water is drained from the bottom and now you have about 35% pure copper mixed with other minerals.  Only then is it ready for the smelting which results in 99% purity.

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