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Chile A Story of Gold and Quicksilver
By Dr. Ralph E. Pray


Chile can be a very friendly and pleasant country to visit. Some of the biggest Chilean smiles are for mining engineers arriving in Santiago.

For arrivals from the U.S. it's a welcome change. Chile can look back on a long history of mining and has, today, one of the most progressive mineral industries in the Western Hemisphere. Chile was producing gold to finance Spain's wars almost one hundred years before the first pilgrim set foot on Plymouth Rock. Gold production has continued since about 1530.

Coming from the States, where interest in mining is at an all-time low, Chile's rich, old mining culture is like a first date, full of promise. I'm traveling from L.A. to examine a large underground gold mine project for U.S. financial interests. For me, working underground goes back to Pioche, Nevada. There, in 1946, fresh out of New York, I worked as a teenage ore-car trammer.

As we drive to the Chile gold mine one of the Chilean engineers asks if I'd like to see a trapiche operation. It's just off of the highway, processing ore from a small gold mine. This sounds like a good idea. I've seen, designed, or built just about every kind of ore-processing plant around, but never a trapiche. We stop off at Plante, Chile a few klicks out of Illapel, between Santiago and La Serena. A simple open roof covers two large rotating wheel assemblies, shiny wet with brown slurry. The lights are on, the motors humming, Two men running the plant greet us with smiles.

I'm fascinated. One man shovels rock in the large concrete tub while the other squeezes mercury off of the amalgam plates with his fingers. Seeing the operation all its simplicity, makes me wonder how I could missed all this in over fifty years of mining work, travel and study.

Rooted to the spot, I watch for twenty minutes before unlimbering the photographic equipment. My intepreters work double time to satisfy my curiosity The video of the trapiche I shoot this first day has been shown in New York skyscrapers and mansions in Beverly Hills.

On my daily trips to the mine I keep returning to this site as a visitor, or more precisely, as a student, to view my "discovery" one more time. While it's unique to me, it is "old hat" to my hosts, of course, just part of everyday life The plant processes over ten tons of ore every 24 hours.

Pyrite, the glittering iron sulfide, sparkles in the rock. At different times, someone shovels ore into the trapiche bowl and periodically releases the slurry. Once the gold is removed, the slurry containing the finely ground waste is drained out of the trapiche bowl, pumped uphill and discharged beside the plant.

I climb the soft trail to the top and view the flat crown of the tailings with alarm. It is huge! Pacing in off along the built-up wall around the edges, I calculate the mass at several hundred thousand tons. The ground ore must go back many, many years. I've seen a few mills, centuries old, south of Santiago that used mule teams to turn the huge stone wheels. Is this the site of such a mill? I feel like I'm standing on a history book.


To More of "Chile, A Story of Gold and Quicksilver" 

Published in the South American Explorer,
June, 2001.
Reprinted with permission of the author. Dr. Ralph Pray, Mining & Metallurgy 805 S Shamrock Ave
Monrovia, CA 91016
Telephone: 626-357-6511 Fax: 626-358-8386