Museum Summer Hours: 9AM to 4PM • Open all days

Mining History

The Superstition Mountain Mining Company (SMMC)

No, we’re not really a mining company. That’s just the name we use for the group of mining exhibits that you’ll experience when you visit the museum.

Follow the Process. When you visit, follow the hard rock mining process from mine to bullion. A map is available in the gift shop and signage along the path explains the stages.

The SMMC Mine – The source of the ore

At the west end of the SMMC operation is the mine. A headframe, originally from a small mine in the Wickenburg AZ area, is typical of the structures that were used for access to hard rock mines in the late 1800s at the hundreds of small mines throughout the Superstition mountain region.

The Arastra – A truly ancient ore mill

Next to the headframe, you will find an arastra. For thousands of years, arastras have been used to grind just about anything needing to be ground. A heavy stone is dragged over a hard surface in a circular motion around a center post. Ore is placed on the hard surface and is ground as the stone passes over it. The more repetitions, the finer the ore becomes. Gold and silver are recovered from the milled ore by amalgamation with mercury.

The Assay Office – The miners map to success

You’re a prospector and you’ve found a source of material that you think may contain gold. Or you have a mine, and you only want to dig the best ore. How do you find out if you’re right or where the best ore is? That’s the assayers’ job.

Assay is the procedure used to measure the amount of valuable metal contained in ore. The assay office, located down the street from the Cossak mill, is a replica of a typical assay office that would have been associated with the Cossak mill. It houses all the period tools that would have been used and signage that takes the visitor through the process from receipt of samples to the final calculation of gold and silver content. A docent is sometimes on hand.

The 20-Stamp Cossak Stamp Mill – The heart of the process

The large wooden structure on the hill overlooking the museum building is the 1914 Cossak 20-stamp ore mill, a critical piece of mining equipment that was state-of-the-art from the mid 1800s to the early 1900s. 

A stamp mill is a large mechanical device, essentially a monster mortar and pestle. It uses lift-and-fall motion of heavy steel stamps to reduce the size of the ore (rock containing valuable metals) it is fed, to a fine sand which is transported out of the mortar box as a slurry through screens.  The milling exposes the valuable metal (usually gold or silver) allowing its recovery by amalgamation with mercury or dissolution with cyanide as was done at the Cossak mill.   

The Cossak operates in season from November to April, generally on Thursdays and the weekends.   Check the Event Calendar for operating schedule.  Bring the family and experience what the millmen in 1914 felt every day.

The SMMC Mine Office – Where the business was done

The SMMC mine office, located next to the assay office, contains photos from the early 1900s and other items from the famous Silver King mine located north of Superior, AZ. The front door is open during business hours.
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