Today we are visiting Minera Spence, another copper mine in the Calama area. This property is owned and operated by BHP Billton. It produces copper from both oxide and sulfide ore deposits, and has been operating longer than than the Centinela sites we visited yesterday.
As always, when visiting an active mine site like this, the first stop is the safety briefing.
Our mine tour begins today at the Esperanza site of Centinela, in part a subsidiary of Antofagasta Minerals. We met the site geologist, Hugo, and received a safety orientation and an overview of the geology and mining operations.
The shape of the porphyry deposit at Esperanza, when you back out more recent faulting, matches well the generalized “lightbulb” model many students learned about in EARTH 380 (Mineral Resources, Economics, and the Environment). This site ranks as the 9th largest copper producer in the world.
We split into two groups, as they can only accommodate a limited number at one time viewing the pit and plant area. The other half examined exploration cores to learn about different parts of the deposit. After which we swapped places.
Thank you to Centinela for providing lunch to us in the company cafeteria as well.
Finally we visited the operations at the El Tesero site. Here we have an oxide-type deposit to contrast with the sulfide type at Esperanza.
We also took the time for some mineral collecting, finding atacamite, copper-oxide, gypsum, chrysacola, etc.
Thanks to Centinela for a great mine visit!
After our very early start yesterday, we slept in til 6:15 this morning. Today we are moving on from the San Pedro de Atacma area back to Calama for the next couple nights. Our main stop today will be to visit the Centinela mine near Sierra Gorda. For now it’s time to drive…and figure out how to clean our windshield.
After starting the day with a spectacular sunrise over the landscape of El Tatio, we are finishing with a panoramic view of the sunset in the Cordella de Sal. As well as some final geology, with gypsum and desert roses.
Just outside of Gaultin we stopped for lunch, and to enjoy the grass, running water, shade, and big cacti. During lunch it became clear that Chilean avocados are much better than what we get in Ann Arbor.
