Letter: More history on Camp Verde Salt Mine
A couple of comments on your excellent history of the Camp Verde Salt Mine.
There are actually TWO historically important mineral deposits at that location. During prehistoric times native peoples mined the site for Sodium chloride, also known as table salt, halite, or NaCl. Much of this was widely traded throughout the Southwest. Early Verde Valley white settlers continued gathering salt here, primarily for use as a condiment, and as a supplement to livestock feed.
The second more commercial mineral deposited here was Sodium sulfate, also known as Thenardite, sulfate of soda, Glauber’s Salt, or Na2SO4. This was the actual “cash crop” mined in Camp Verde during the first third of the 20th Century. Its most important uses during this period were the treatment of wood pulp to transform it into cardboard (the Kraft Process), and its addition to molten glass to remove bubbles.
Other lesser and more recent uses includes as a human laxative, a filler in laundry detergents, a textile drying agent, a diluent for food colors, a window defroster, a carpet freshener, and as an antidote for Acetaminophen poisoning.
The two minerals were laid down in separate overlying beds, but today examples of both can be found in the rubble surrounding the mines. The crystals differ and are easily distinguished in that Thenardite is white, completely opaque, and does not taste “salty.” The true salt crystals are gray, and do allow some light to pass through.
The mine had a number of owners, most locals, before it became unprofitable during the Great Depression.
An attempt to reactivate it in the 1950s was unsuccessful. Its peak was reached in 1917-1918 due to World War I needs, and the shutoff of imports from Europe.
Horse- and mule-drawn wagons and truck-loads of over 90% pure Thenardite ore arrived almost daily at the concrete bins next to the tracks in Clemenceau, the closest railroad to Camp Verde.
When a sufficient amount was gathered to fill an order for the paper mills in the southeastern United States, or the glass factories in Ohio and Pennsylvania, it was loaded into gondola cars and shipped out of the Valley via Clarkdale, Jerome Junction (=Drake), and Ash Fork.
Donald E. Hahn