Mining activity in and around the Atascosa Mountains just north of the border with Mexico in Santa Cruz County dates back to the Spanish; perhaps overseen by the Jesuits, and later Mexicans, who prospected heavily for gold.
Heightened mining operations occurred during the 1870s when prospectors arrived in the Arizona Territory, reworking the old Oro Blanco Mine near the border. Multiple claims were staked on the Oro Blanco vein resulting in the settlement of Oro Blanco.
The Oro Blanco camp began with a population of 40 miners, increasing a decade later to 225 people, including land baron, miner and cattleman James A. Robinson. He was then Arizona’s wealthiest man, who reportedly lived at the site in 1899 with a fortune estimated at $1.8 million.
The town was sustained by additional mines classified as the Warsaw group consisting of the Yellow Jacket and Ostrich mines.
A mill was erected at the Ostrich Mine during the 1880s. It was equipped with a roasting furnace that treated the refractory sulfide ores. The mill’s operations were overseen by the Orion Co., and the ore processed came from the Montana and Warsaw mines.
The Warsaw mill built in 1882, along with another mill built two years later by the Esperanza Mines Co., treated ore from the Blain ledge.
Milling ceased in the late 1880s, only to be resumed a decade later with many small mills built to service the Oro Blanco and Golden Eagle mines.
Several amalgamation and cyanide mills were also built in the early 1900s.
Concentrating tables such as the Wilfley Table, designed by Arthur R. Wilfley in 1896, were heavily used in the area.
These tables consisted of a rectangular deck measuring around 6 feet by 12 feet with an adjustable slant. Riffles composed of wooden strips ran from the feed end to the discharge end. A slurry of ore mixed with water was sent down in a diagonal line while the entire device used a reciprocating motion.
Minerals were separated by their specific gravities, captured behind the riffles and discharged at the end. The lighter gangue, or worthless, material was washed over the side.
Although the table was not efficient in the separation of finely ground material, it was credited with having captured over 65 percent of the sought-after minerals.
By 1931, Santa Cruz County was credited with having produced over $1.2 million worth of gold, over a quarter of which was a byproduct from copper and lead ores.
Amado Station, 36 miles northeast of Ruby, served as a railroad junction connecting the local mines to the Nogales branch of the Southern Pacific Railway.
Louis Zeckendorf of Tucson took a personal interest of the Montana Mine in 1907. It was historically the greatest-producing mine in the district. It proved to be a notable lead-zinc-copper deposit accessible at the Ruby townsite.
Production increased under the Goldfield Consolidated Mines Co. in 1916 and a decade later by the Eagle Picher Lead Co., credited with having erected a 250-ton flotation mill onsite.
A total of 773,197 tons of gold, silver, copper, lead and zinc were milled by the time the company ceased operating the mine in 1941.
Later leased by Hugo W. Miller of Nogales, the Montana Mine produced a total of 2,000 tons of ore shipped prior to the depression of the zinc-lead market and the closure of the mine in 1952.
The nearby Austerlitz Mine, 2.75 miles northwest of Ruby, provided access to a flat vein of gold. Early production in the 1890s comprised a minimum recorded figure of $90,000. It produced a marginal product in the 1930s and was later acquired by Fred Noon in 1959.
Other producing mines in the district include the Tres Amigos, Dos Amigos, Old Glory, and Margarita .
The product from these mines, with several thousand feet of underground workings, averaged 10 ounces of silver per ounce of gold. The Margarita Gold Mines Co. operated a 50-ton cyanide mill, producing marginal lots of bullion supplied by water from Old Glory Canyon.
While active claims continue to exist throughout the district, there currently is no large-scale production of gold.
