Our first stop on the day trip was at the Asarco Mineral Discovery Center. This is the visitor center for a working open pit copper mine, and is the starting point for a most interesting tour. A small museum with artifacts from mining in the day and an outside display of equipment used over the years.
The overall statistics are hard to understand: The mine operates 24 hours a day, 365 days a year. The copper ore represents about 1% of the "dirt" hauled to the processing plant, so incredible amounts of material are excavated.
The material is excavated by blasting a carefully plotted section of the side of the mine along a shelf or step. The dirt is loaded onto haul trucks that carry 340 cubic yards of material to the processing plant at the rate of 6 1/2 miles an hour, requiring about an hour to complete a round trip. The material from one truck yields about 2880 pounds of copper, meaning that each truck at todays prices, provides a gross $7,300 per trip. Twenty four hours a day, every day….you do the math. However, EPA regulations and operating costs erode about 95% of that amount, meaning that the mine is barely making a profit. Traces of other minerals are also found, in fact, the amount of silver found pays for the plants' million dollar electric bill.
The immense size of the excavation is hard to visualize. The pit is approximately 2 1/2 miles across on the long axis and 1 mile across on the "short" side. Each day it changes, growing a bit wider and deeper, and in fact, new haul roads need to be constructed about every two weeks.
The huge haul trucks crawl up out of the pit one right after another, stopping only during blasting.
Each truck dumps at the bottom of the ramp at the left of the following pic, where the material is initially crushed from pieces about five feet in diameter to pieces about a foot in size.
These pieces are fed into huge "ball mills" where rotating drums partially filled with steel balls of varying size crush the rock into beach sand size. Then to another mill where the balls are smaller to produce a slurry that resembles grey mud.
The slurry is mixed with a variety of chemicals including pine oil (yes, from pine trees). Small amounts of sulfur in the slurry create sulfuric acid and lots of bubbles. The pine oil precipitates the copper onto the surface of bubbles where it is separated from the residue.
The residue, or tailings, is/are floated out to huge ponds, where water is recycled and the dry material is moved to a disposal site.
This shovel is roughly half the size of the ones currently in use. The new shovels will load a haul truck in three scoops! That's 300 plus tons!
This engine powered the haul truck just visible in the background. Note the gentleman standing in front of it. The current haul trucks are double the size.
The specs on the engine are interesting to a gear head. The fuel consumption is a little scary, though!
Just as Donna was making sure that I knew just how small I am in this universe, we met some people from Iowa.
It turns out that in each of the last two years we have stayed a few days about a mile or so from their farm! We chatted about farming, traveling, and life in general for a bit, and came away with a new understanding of farming in the midwest. We immediately liked Dave and Marylu, and hope to see them again. What a wonderful co-incidence! Happy travels, you two!
Our second stop of the day was at the Titan II Museum near Green Valley, AZ. This is the sole remaining Titan II facility in the country. Other sites remain from the Minuteman missile days, but only this one of the original 54 Titan II sites remain.
The tour starts at the museum, where the American Flag was flying briskly in a 30+ mph wind.
One of the first things a visitor sees is a mockup of the warhead. Roughly eight feet long and four feet in diameter, it's difficult to imagine that this is a 9 megaton nuclear device. Our guide told us later that 9 megatons is equivalent to nine million tons of tnt, which, if formed like dynamite and placed in boxes and loaded into railroad containers and prepared for travel, would result in a train that stretched from Tucson to Canada!
Sam, our guide, is standing beside the main booster engine of the Titan II, mounted in a framework. It is extraordinarily small, since it's simply a plumbing device bringing together two oxidant chemicals and focusing the resulting blast downward.
Sam showed us the blast doors as we descended 55 steps to the control room. The doors are 12" thick, and locked with steel pins that secure the door at each corner. Weighing 6000 lbs, a young man on the tour was able to move the door with little effort.
The control room has the appearance of something from a B science fiction movie, but it was state of the art in 1966. The commander sits at the console in front, and communicates with the lieutenant commander seven feet away. Each person has separate keys, codes, and duties, which all have to mesh to launch the missile.
The entire control room is suspended from these huge metal springs to dampen movement that may disturb the missile just a few feet away. The red filing cabinet is the safe where the launch codes are kept. At each shift change, the safe would be opened and the contents verified before command is transferred. The two locks must be opened by two individuals who have independently verified an order to launch. In addition, several specific protocols have been initiated and verified, including an order direct from the President of the United States containing a specific, one-time use, code that must be manually entered using a 16 digit rotating dial much like a combination lock.
This is the master clock, set to military time. Known as Zulu time, it is Greenwich Mean Time. This is the launch clock specifying the actual launch time. This may be minutes or hours after the order to launch, so that the various missiles flying about the globe wouldn't crash into each other.
This is the local time clock. Know as the Lunch clock to distinguish it from the Launch clock.
A walk through a tunnel, again suspended from springs, brought us to the actual silo.
At 103 feet tall, it is awe inspiring. The Titan II was such a useful device that it not only protected our country but powered all of the space exploration missions of the '60's, '70's and '80's. Every one of the missiles that was manufactured was used, either for Apollo and Gemini missions or to place satellites in orbit. The technology of the Titan II reduced the launch time from the two to threes hours required by the Titan I to 58 seconds!
One interesting question that was asked near the end of the tour had to do with the white "smoke" that we see in pictures during launch. That is actually steam, produced by pumping ninety thousand gallons of water a minute into the main engine area, starting milliseconds after ignition. The steam damps the acoustic vibrations in the narrow silo, and provides a rapidly expanding boost to the rocket as it exits the silo.
The launch codes containing the destination co-ordinates were pre-loaded into the rocket guidance computer, and the actual target was selected via the codes from the President. There was absolutely no communication possible between the launch control members and the missile after launch. Once it was gone, it was gone. On the theory that any communication protocol could be "hacked", it was a one-time operation. If a launch had ever been ordered, the crew had food and water for a month, but only had air for a few days. A tunnel topside provided "scrubbed" air as necessary, but the crew had to wait for further orders as to when to exit the silo, which was designed for only one use (which thankfully never happened). The guidance system on the rocket was so precise that it determined the length of burn for the two stages of the rocket and the precise millisecond that the engines ceased burning and fell to earth in a trajectory that would place it within a mile of it's intended target!
All in all, a very informative tour with a great guide. Sam lives in the area and has logged over 6,000 hours of volunteer work at the museum. Great tour, Sam!
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