Planchas de Plata (Spanish for ''slabs of silver''), sometimes called Bolas de Plata (''balls of silver'') is a historic silver-mining district near

Nogales, Sonora Heroica Nogales (), more commonly known as Nogales, is a city and the county seat of the Municipality of Nogales. It is located on the northern border of the Mexican state of Sonora. The city is abutted on its north by the city of Nogales, Arizo ...

Mexico Mexico (Spanish: México), officially the United Mexican States, is a country in the southern portion of North America. It is bordered to the north by the United States; to the south and west by the Pacific Ocean; to the southeast by Guatema ...

, and a few miles south of the border with the US state of

Arizona Arizona ( ; nv, Hoozdo Hahoodzo ; ood, Alĭ ṣonak ) is a state in the Southwestern United States. It is the 6th largest and the 14th most populous of the 50 states. Its capital and largest city is Phoenix. Arizona is part of the Fou ...

Native silver Silver is a chemical element with the symbol Ag (from the Latin ', derived from the Proto-Indo-European ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical co ...

was discovered here in 1736 by Antonio Siraumea, a

Yaqui The Yaqui, Hiaki, or Yoeme, are a Native American people of the southwest, who speak a Uto-Aztecan language. Their homelands include the Río Yaqui valley in Sonora, Mexico, and the area below the Gila River in Arizona, Southwestern United Sta ...

Indian, on the ''Rancho Arizona'' of Bernardo de Urrea. Historian Donald Garate believes Urrea's Arizona Ranch to be the likely source of the name of the present US state of

, and he claimed the origin of the name of the ranch was the Basque phrase "aritz ona" (''good oak''). Other historians have, however, debated this. For more detail on the etymology of the name Arizona, see

. Prospectors and miners rushed to the area of the great silver discovery of October, 1736. It was given the name ''San Antonio de Padua'' by ''Justicia Mayor'' Juan Bautista de Anza when he arrived on the scene in November and ordered that all the silver that had been taken from the site be impounded and brought to Urrea's Arizona Ranch, some fifteen miles down the canyon. Because the large pieces of silver were found in a placer deposit (unusual for silver, and unique for such large masses) the Spanish colonial government maintained that the silver was an artificial

treasure trove A treasure trove is an amount of money or coin, gold, silver, plate, or bullion found hidden underground or in places such as cellars or attics, where the treasure seems old enough for it to be presumed that the true owner is dead and the hei ...

and so belonged to the crown. The miners maintained that it was a natural placer deposit that belonged to the discoverers under Spanish law. The court case dragged on for years, and in the meantime, Spanish soldiers ejected the miners. Because his ''escribano'' (scribe), Manuel José de Sosa, dated all the impounding documents at Arizona, people in faraway places like Guadalajara and

Mexico City Mexico City ( es, link=no, Ciudad de México, ; abbr.: CDMX; Nahuatl: ''Altepetl Mexico'') is the capital city, capital and primate city, largest city of Mexico, and the List of North American cities by population, most populous city in North Amer ...

were soon referring to the silver as the "silver of Arizona." ''Arizona'' became a household word in early 18th century Mexico, associated with great and sudden wealth. Some modern writers on

lost mines Lost mines are a popular form of lost treasure legend. The mines involved usually contain a high-value commodity such as gold, silver or diamonds. Often, there is a map (sometimes called a "waybill") purportedly showing the location of the mine ...

have assumed Planchas de Plata to be "lost," although the location has always been well known. After the initial placer silver discovery, the district was idle until silver veins were discovered in the vicinity, and between 1872 and the 1930s, at least six mines operated, and ore was treated by a stamp mill and

pan amalgamation The pan amalgamation process is a method to extract silver from ore, using salt and copper(II) sulfate in addition to mercury. The process was widely used from 1609 through the 19th century; it is no longer used. The patio process had been used t ...

. The amount of silver produced is not known, although the amount of ore mined has been estimated as between 50,000 and 100,000 tons. No mining has been done since the 1930s, but a Canadian firm has had some encouraging results from exploration drilling in 2007.Minefinders Corp. Planchas de Plata project
/

References and further reading

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public domain The public domain (PD) consists of all the creative work to which no exclusive intellectual property rights apply. Those rights may have expired, been forfeited, expressly waived, or may be inapplicable. Because those rights have expired, ...

article produced by the US

National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational propert ...

External links

Canadian company acquires historic Planchas de Plata district
at

. {{DEFAULTSORT:Planchas De Plata, Sonora Geography of Sonora Pre-statehood history of Arizona Silver mines in Mexico 1736 establishments in North America Silver mining in the Spanish Empire