The DCGIA gathered in the Georgetown Room on Thursday, September 23, 2010 to share memories of trips to several Arizona mines as some members had joined the presenter, Helen Serras-Herman and her husband, Andy on some of the visits.
The first slide redefined the meaning of big truck as the axel of the truck was about even with Andy’s head. Helen began by reminding us all of her connections with the area and many of the GIA members over the years. She gave a brief overview of more than 100 years of silver, copper and gold mining and the associated minerals azurite, chrysocolla, malachite, and, of course, turquoise. She then took us on tours of open-pit mines and an underground mine in Arizona.
The presentation was a summary of the article that appeared in the July 2010 issue of Rocks and Gems, ppg. 58-62, entitled “Six Southern Arizona Mines.”
Helen started our tour at Asarco Mission Mine approximately 15 miles south of Tucson. This is an open pit copper mine that allows tours. One photograph showed 70 and 150 ton trucks that are used to haul ore to the crusher and she also showed a network of conveyor belts used to move rock from the crushers to the flotation units which allowed separation of the metals from the matrix. The metals are recovered by electrolysis and then sent to Texas for precious metal recovery. Our next stop was Tombstone, AZ to see the Good Enough and Tombstone mines. Good Enough was discovered in 1875 and started as a silver mine, Good Enough was reopened for tourists in 2007, but is not a working mine. The tombstone mine is a working mine, and it is not open to the public. However, some finds from the mine are available in the local stores.
This area is a great tourist attraction based on the history of the town. Shoot-outs at the OK Corral happen every day for tourists. Bisbee was the next stop, home of the Bisbee Queen Mine. In 1800, Bisbee was the largest city between St. Louis and San Francisco and had 20,000 inhabitants. Between 1877 and 1975 this mine produced more that 8 billion pounds of copper. The Lavender Pit in Bisbee was the source of the greatest azurite and lapis lazuli in the area. The Bisbee blue turquoise is world famous. The Morenci Mine is near the New Mexico border in Clifton. It is still a working mine employing more than 2,000 people. This mine uses 270 ton trucks to move the ore from the source in the pits to the crushers. This mine produces 840 million pounds of copper per year. The last mine in our arm-chair tour was the Ray mine near Globe and Superior. The closest town was originally Senora, but the town was torn down as the mine excavated the land where the town’s original location. Near the mine, in Miami, is an excellent museum.
Helen told us only one per cent of turquoise is natural. Ninety-nine percent of the turquoise must be treated in order to cut and polish the stone.
Helen ended her presentation with photographs and displays of her Copper Trail jewelry.
Meeting Summary by Gerry Cox
Photos by Bobby Mann