Fourteen million years ago, on the spot that would later become the old town of San Cristobal, pictured at right, bubbling hot springs at the bottom of a fresh water lake deposited layers of lead, zinc, and silver sulfides. Occasionally the water would burst into violent boiling, killing whatever fish were in the lake, and killing most of the trees on the shore. (In those days, the Altiplano of Bolivia had trees and a milder, wetter climate).
Those who built the old town of San Cristobal unknowingly built it directly on top of the silver deposit. In the photo of the mine pit to the left, the town used to be right where the deepest hole now carves out the landscape. The overall open pit, when finished, will be 250 meters deep (as deep as an 80 story building is tall!); and hopefully, someday, will return to being a lake again, though none of us will be around to see it.
Not only does the mine rank as the third largest silver producer, but it is the fourth largest zinc producer in the world. It mines 60,000 tonnes of ore per day and 120,000 tonnes of waste per day (waste is rock that has no silver in it but must be removed in order to get at the silver-bearing rock).
The mined rock has only 2 ounces of silver per tonne, and about 35 pounds of zinc per tonne, thus the overall value per tonne is not much (about $120 per tonne at today’s prices). Only 80% of that amount can be recovered, and with the Bolivian government taking 50% in taxes, the margin for profit is quite small. It does, however, create 4600 well-paying jobs in a country desperate for employment. And there is enough ore there to last about 34 years, so it will lift an entire generation out of poverty.
The new town of San Cristobal, pictured at right, has a very different look than the old town. Some may say it has lost some of it’s previous charm. The llamas, however, don’t seem to mind.
The benefits of the silver discovery include many lifestyle improvements such as the construction of two-story homes like the one pictured below, an internet cafe, a bank, a beauty parlor, and a greenhouse.
We wonder what our readers think of the transformation of the town of San Cristobal?