Maricopa County

Ambrosia Mill

This manganese mill processed ore from the nearby Purple Pansy & Black Queen Mines.

Equipment operating at the mill site sometime in the 1950s or 60s. 2011-03-0830, ADMMR Photo Archive, Arizona Geological Survey.

Equipment operating at the mill site sometime in the 1950s or 60s. 2011-03-0830, ADMMR Photo Archive, Arizona Geological Survey.

Ambrosia Mill is a former mill site located along Eagle Eye Road 10 miles south of Aguila. The mill sits near the base of Harquahala Mountain but remains gated off. The mill processed ore from numerous nearby mines from the late 1950s to early 1960s.

The mill was likely constructed sometime in the mid-1950s. The location was chosen based on the proximity to rail lines in Aguila and semi-reliable water along Tiger Wash. It is unclear when exactly it was built, but in early 1958, the Rico Mining Company, based in Aguila, was leasing the mill. The company was owned by the Evans brothers and was processing ore from the nearby mines which included the Black Bart, Black Queen, and Purple Pansy. The mill & mines were owned by the Ambrosia Mining Company, but soon closed down by late 1959.

In 1961 the mill was being retro-fitted to produce aggregate. Later that year, the mill was up and running, producing manganese concentrate. A crew of eight ran the mill and processed both the old tailings piles and new incoming ore from area manganese mines & quarries. Ore brought in ran between 5-8%. The mill was able to process 400-500 tons per day, and the final concentrate product averaged around 40% manganese. This was then hauled via truck to Aguila where it was then distributed to clients in Henderson, Nevada and Mexican Hat, Utah. The concentrate was used in uranium circuits.

The mill ran with limited success through the 60s. The site was abandoned sometime in the 1960s or 1970s. Some equipment and numerous tailings piles were left and remain today. The property today remains securely gated and fenced off. No signs remain along the perimeter, however. It appears that the property was at one point seized by the county for unknown reasons. Much of the tailings can be seen from outside of the fence, and metal tanks dating to 1958 remain nearby. For some reason, an abandoned runway remains as part of Ambrosia Mill. It is unclear why or when this was constructed here. Lack of any details on this only adds to the rumors of what this was used for.

Aerial look at Ambrosia Mill ruins.

Metal tanks (dated 1958) remain at Ambrosia Mill.

A look at milling equipment & foundations left on site.



  1. “Ambrosia Mill.” Western Mining History,

  2. “AmbrosiamillMaricopa157.Pdf.” Arizona Department of Mines and Mineral Resources Mining Collection, Arizona Geological Survey,

  3. Historic photo of Ambrosia Mill operating sometime in the 1950s or 60s . 2011-03-0830, ADMMR Photo Archive, Arizona Geological Survey.