April was a busy month for field trips by the SaddleBrooke Nature Club. April 12 was a journey to the big hole of the Asarco Pima Copper Mine and April 26 was a trip to the heavens and earth at the Flandrau Planetarium and Mineral Museum.
Members gathered at the Asarco Mineral Discovery Center just off I-19 North of Sahuarita. This free museum has many excellent exhibits covering the mine itself and the copper mining industry in general. We began our tour with a short lecture about the Asarco Mine and what we would be exploring on our tour of the mine. Then we headed out to the tour bus and began the journey up to the top of the Big Hole. Impressive indeed! The mine measures 2.5 miles long by 1.5 miles wide and is 1200 feet deep. Even looking down to the bottom of the pit with powerful telescopes, the huge machinery still looked small. These machines are amazing in their size. The electrically powered shovels scoop up a load of rock larger than a backyard swimming pool. Then it deposits the mineral-bearing rock into a dump truck the size of a small house. Fully loaded these trucks weigh 1.2 million pounds! Even the tires are huge, standing about 10 feet tall and costing $100,000 each for the six required.
We then headed to the processing facility where the minerals are separated from the overburden. Boulders the size of a small car are crushed and refined down to the consistency of a fine powder. This product is then immersed in a solution that separates the minerals from the waste. The next step in the process is a trip to Hayden, Arizona where the powdered minerals are turned into the sheets of 99% copper you frequently see driving down Oracle Road. These sheets are headed to Amarillo, Texas where they are further refined to 99.99% copper for industrial use.
The demand for copper and other metals continues to rise. Over two billion people in the world currently without electricity are expected to be wired to the grid within the next 50 years.
Our next adventure was to the University of Arizona for a tour of the Universe. We ventured into the planetarium for a view of the night sky over Tucson. After a lesson on the numerous constellations visible in the local area, we continued on a journey of the Milky Way Galaxy and then beyond to the limits of the current knowledge of the universe.
Next we ventured deeper in the museum where we tried our skills at solving numerous math and logic puzzles. These challenges are mostly meant for children, but the adults in our group all enjoyed the brain teasers. Then it was downstairs to the world class mineral museum. This facility has thousands of specimens of rocks, gems and minerals from around the world. The variety and beauty of the raw materials and then processed art and jewelry was truly amazing.