Gold, Arsenic, & The El Dorado Death Spring

The information that I find in old newspaper archives sometimes surprises me. It's those times, like now with the news story below from 1855, that make me shake my head in disbelief. 

I found this in the Georgetown News, Volume 1, Number 41,  July 26, 1855,

El Dorado Death Spring.

This name is given to a spring in this county by the Placerville American [newspaper]. Its waters are said to flow from a bed of arsenic. That paper says: 

“Col. Henderson, County Surveyor of El Dorado, and a resident of our city, has in his possession a specimen of auriferous ore of Arsenic, which he will show to anyone interested in the development of the mineral wealth of El Dorado County. 

This specimen has a bright silvery appearance, with particles of gold mixed; the bulk of the specimen, however, is the bright ore of Arsenic. One specimen carefully analyzed yielded eight dollars of pure gold to the single ft. of ore, while numerous specimens yielded $3.60 of gold to the pound. 

"But the most striking feature of it all is the vastness of the deposit. We are assured by Col. Henderson that it is thirty feet thick (we use no figures in this, that our readers may not mistake us) and crops out above the surface of the ground. We would not convey the impression that all of this vast deposit contains gold, but that there are veins in it, exceedingly rich. 

“Col. Henderson, like a sensible man, keeps the matter of locality entirely to himself, considering that his fortune is there, waiting only an opportunity for its development. Here, then, is a field for the capitalist; a bed of auriferous ore of Arsenic thirty feet thick, and of unknown extent. Is it surprising then, that gold miners upon the placers in that vicinity, at an early day, drinking the sweet arsenical waters, should be seized with fevers, and a burning thirst, which from day to day increased until their graves marked the spot of their sojourn?”

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Georgetown News, Volume 1, Number 41,  July 26, 1855

I was very surprised to find out that gold is frequently found with arsenic. After doing a little research, I found out that arsenic has the ability to stabilize gold within the structure of these minerals. Arsenic actually plays a crucial role in the formation of gold deposits by allowing gold to penetrate mineral structures and stabilize within them.

According to research by geochemists, gold and arsenic are often found together in gold deposits, and their bond is due to an atomic-scale attraction between the two elements. The structure of certain minerals helps facilitate this attraction, effectively concentrating gold within those minerals.

Gold is often found with iron and arsenic-containing minerals like pyrite and arsenopyrite. These minerals act like sponges, concentrating gold levels significantly higher than in other geological contexts. So, yes, it's said that the presence of arsenic can be an indicator of potential gold deposits. And yes, that means higher arsenic concentrations suggest higher gold deposits. 

Of course, while arsenic is often found in gold deposits and is a common byproduct of gold mining, especially in the 1800s, it's not directly used in the gold extraction process itself. But arsenic is a significant component of the ores and can be released into the environment during mining activities.

Imagine that! 

Tom Correa