The tires are pressured to 200 lbs, and are filled with nitrogen rather then air as nitrogen will not heat up and thus will maintain constant pressure. We were allowed to climb all over one of the monsters to get a feel for what it was like to drive one. Following the trucks along we soon arrived at the crusher. This breaks the rock down to smaller size and dumps it onto a conveyor belt which carries it quite a way to a building called the concentrator. High grade ore arriving at the concentrator has about 40 to 60 lbs of copper per ton. It is in the concentrator that the heaviest cost is occurred. As we climbed the 182 steps that took us along the cat walks over the massive machinery, with our ears protected with plugs and eye protectors in place, we were told that the rock is dumped into tumblers which contain steel balls, very large to start with and graduating down as the rock breaks up and finally turns into a powder with a consistency smaller then sugar. This is mixed with a reagent which causes a bubbly mixture. Copper and the other minerals being lighter then much of the conglomerate, floats to the surface and is skimmed off, the remainder becomes more fill. There is a fast pass through a sediment tank which allows more debris to settle out before the muddy mixture is sent on to the smelter. The mixture has been concentrated to about 25 percent copper by this time. About 400 thousand tons of ore are processed each day at a cost of some 4 megawatts per machine, for which there were a half dozen or so, and over 20 million gallons of water per day. The water is recovered. The electricity is not. Recent electrical shortages in California have cut into the available power for the plant and threatens to shut down the whole operation. At the smelter, the mess is dried and then fed into the furnaces. Heated up to around 3000 degrees, the copper liquefies and seeks it own specific gravity separating it from all the other minerals present. It is poured off into ingots at around 99.8 percent pure. The molds are actually solid copper lined with ceramics and potash which works like greasing a pan. Once heat is removed the copper solidifies quickly and within minutes is popped out automatically and stacked for further cooling. The whole process is controlled by one person in a glass insulated enclosure who monitors the process and makes adjustments where necessary. The one furnace we were at produced an ingot about every 30 seconds. One of the side products of reducing copper sulfate is sulfur, which is mixed with water to form sulfuric acid, another product sold across the nation. Some of the sulfuric acid makes it way back to the mine to be used as part of the second copper extraction method. Low grade ore is piled into large hills to which is added hundreds of small vertical water lines. A very weak solution of sulfuric acid is dripped out of the lines and allowed to seep through the hill. The resulting liquid which is collected at the bottom is rich with dissolved copper. This water is pumped into a large holding tank. A 20 lb. piece of copper is lowered into the water after which some 13000 volts is passed through the tank. The result is a form of extrapolating as the copper jumps out of the water and attaches itself to the copper plate. It is removed when around 320 lbs of 99.9 pure copper is attached. The solution is then recycled. This goes on day after day, month after month. Once in a while as the solution begins to deplete, the hills are turned much as the ground would be with a plow. This exposes new material and the process starts over again. This is the most economical and environmentally prudent method of extracting copper and, according to our guide, may someday be the only approved method. It took over 4 hours to take the tour but the time flew by. Fritz was delightful and the company allowing us to get up close and personal to so much of the operations was wonderful. For those who like to follow processes this is a great way to spend the day.

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