Planchas de Plata, Sonora facts for kids
Planchas de Plata means "slabs of silver" in Spanish. It's also sometimes called Bolas de Plata, which means "balls of silver." This historic area is known for its silver mines. It is located near Nogales, Sonora, Mexico. This spot is just a few miles south of the border with the US state of Arizona.
In 1736, a Yaqui man named Antonio Siraumea found pure, natural silver here. He found it on the Rancho Arizona, owned by Bernardo de Urrea. Some historians, like Donald Garate, think this ranch might be where the state of Arizona got its name. Garate believed "Arizona" came from a Basque phrase meaning "good oak." However, other historians have different ideas about the name's origin. You can learn more about the name Arizona in the Arizona article.
Toward the end of last October, between the Guevavi Mission and the ranchería called Arizona, some balls and slabs of silver were discovered, one of which weighed more than one hundred arrobas (2,500 pounds), a sample of which I am sending to you, Most Illustrious Lord. --Captain Juan Bautista de Anza to Bishop Benito Crespo, January 7, 1737.
Contents
The Big Silver Discovery
In October 1736, a huge discovery of silver was made. News spread quickly, and many prospectors and miners rushed to the area. Captain Juan Bautista de Anza, a Spanish official, arrived in November. He named the site San Antonio de Padua.
Silver Taken and Held
Captain Anza ordered that all the silver found at the site be collected. It was then taken to Urrea's Arizona Ranch, about fifteen miles away. This was done to keep track of the valuable silver.
A Royal Dispute Over Silver
The large pieces of silver were found in a "placer deposit." This means they were found loose in dirt or gravel, like gold nuggets in a riverbed. Finding such big pieces of silver this way was very unusual.
Who Owns the Silver?
The Spanish government claimed the silver was like a "treasure trove." They said it was an artificial collection, not natural, and therefore belonged to the Spanish Crown. But the miners disagreed. They argued it was a natural placer deposit. Under Spanish law, natural deposits belonged to the people who discovered them.
The Long Court Case
This disagreement led to a long court case. While the case dragged on for years, Spanish soldiers forced the miners to leave the area.
Arizona's Famous Silver
The official scribe, Manuel José de Sosa, wrote down all the documents about the silver at Arizona Ranch. Because of this, people in faraway cities like Guadalajara and Mexico City started calling it "the silver of Arizona."
A Name Becomes Famous
Soon, the name Arizona became well-known throughout Mexico. It was linked to stories of great and sudden wealth.
Later Mining Efforts
Some modern writers have mistakenly thought Planchas de Plata was a "lost mine." However, its location has always been known.
Mining After the First Discovery
After the first big silver discovery, the area was quiet for a while. Later, new silver veins were found underground. Between 1872 and the 1930s, at least six mines were active. They used special machines like a stamp mill to crush the ore. They also used a method called "pan amalgamation" to get the silver out.
How Much Silver Was Found?
We don't know the exact amount of silver produced. But it's thought that between 50,000 and 100,000 tons of ore were mined. No mining has happened since the 1930s. However, a Canadian company did some test drilling in 2007 and found promising results.
