Placerville, Colorado
Encyclopedia
Placerville is an unincorporated town
and a U.S. Post Office
located in San Miguel County
, Colorado
, United States
. The Placerville Post Office has the ZIP Code
81430.
gold
mines located on the San Miguel River
and Leopard Creek. The location became known as Old Placerville after the Rio Grande Southern Railroad
constructed a depot and several passing sidings west of the original settlement, calling it Placerville.
A. B. Frenzel discovered vanadium
-bearing sandstone near Placerville in the late 1890s. The ore was in strataform bodies in the Entrada Sandstone
(Jurassic
) east of the town. The principal mineral was roscoelite
, with minor montroseite and carnotite
. By the fall of 1899, development was described as "of the most superficial character," although Frenzel had driven one tunnel 18 feet into the rock. By 1901-1902, Frenzel was excavating several thousand tons intended for shipment to Europe
. Most of the Placerville ore was less than 3% vanadium, too low grade to pay for shipment to Europe, so in 1905 the Vanadium Alloys Co. built an ore-processing mill southeast of Placerville to recover the metal as ferro-vanadium, which it sold. At least five mines were active at one time, and by 1919 the two ore mills at Placerville were producing 30% of the world's vanadium. Through 1940, the mines produced about 3.7 million pounds of vanadium.
Although carnotite
was recognized as a minor constituent of the ore since its discovery, the amount was small, and no assays were made of the uranium content of the ore until World War II. Beginning about 1950, the small uranium content of the ore was also recovered from the ore.
Unincorporated area
In law, an unincorporated area is a region of land that is not a part of any municipality.To "incorporate" in this context means to form a municipal corporation, a city, town, or village with its own government. An unincorporated community is usually not subject to or taxed by a municipal government...
and a U.S. Post Office
United States Postal Service
The United States Postal Service is an independent agency of the United States government responsible for providing postal service in the United States...
located in San Miguel County
San Miguel County, Colorado
San Miguel County is one of the 64 counties of the state of Colorado of the United States. The county is named for the San Miguel River. The county population was 6,594 at U.S. Census 2000...
, Colorado
Colorado
Colorado is a U.S. state that encompasses much of the Rocky Mountains as well as the northeastern portion of the Colorado Plateau and the western edge of the Great Plains...
, United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
. The Placerville Post Office has the ZIP Code
ZIP Code
ZIP codes are a system of postal codes used by the United States Postal Service since 1963. The term ZIP, an acronym for Zone Improvement Plan, is properly written in capital letters and was chosen to suggest that the mail travels more efficiently, and therefore more quickly, when senders use the...
81430.
History
Placerville was originally established as a small mining camp, named after the placerPlacer
Placer may refer to one of the following:*Placer deposit*Placer sheep*Placer mining*Placer, rugby league football role.Geographical names:* Placer, Masbate, Philippines* Placer, Surigao del Norte, Philippines...
gold
Gold
Gold is a chemical element with the symbol Au and an atomic number of 79. Gold is a dense, soft, shiny, malleable and ductile metal. Pure gold has a bright yellow color and luster traditionally considered attractive, which it maintains without oxidizing in air or water. Chemically, gold is a...
mines located on the San Miguel River
San Miguel River (Colorado)
The San Miguel River is a tributary of the Dolores River, approximately 90 mi long in southwestern Colorado in the United States...
and Leopard Creek. The location became known as Old Placerville after the Rio Grande Southern Railroad
Rio Grande Southern Railroad
The Rio Grande Southern Railroad was a narrow gauge railroad which ran from Durango to Ridgway in the western part of the US state of Colorado...
constructed a depot and several passing sidings west of the original settlement, calling it Placerville.
A. B. Frenzel discovered vanadium
Vanadium
Vanadium is a chemical element with the symbol V and atomic number 23. It is a hard, silvery gray, ductile and malleable transition metal. The formation of an oxide layer stabilizes the metal against oxidation. The element is found only in chemically combined form in nature...
-bearing sandstone near Placerville in the late 1890s. The ore was in strataform bodies in the Entrada Sandstone
Entrada Sandstone
The Entrada Sandstone is a formation in the San Rafael Group that is spread across the U.S. states of Wyoming, Colorado, northwest New Mexico, northeast Arizona and southeast Utah...
(Jurassic
Jurassic
The Jurassic is a geologic period and system that extends from about Mya to Mya, that is, from the end of the Triassic to the beginning of the Cretaceous. The Jurassic constitutes the middle period of the Mesozoic era, also known as the age of reptiles. The start of the period is marked by...
) east of the town. The principal mineral was roscoelite
Roscoelite
Roscoelite is a green mineral from the mica group that contains vanadium.The chemical formula is K2AlSi3O102.Crystals of roscoelite take on the monoclinic form, and are from the 2/m point group....
, with minor montroseite and carnotite
Carnotite
Carnotite is a potassium uranium vanadate radioactive mineral with chemical formula: K222·3H2O. The water content can vary and small amounts of calcium, barium, magnesium, iron, and sodium are often present.-Occurrence:...
. By the fall of 1899, development was described as "of the most superficial character," although Frenzel had driven one tunnel 18 feet into the rock. By 1901-1902, Frenzel was excavating several thousand tons intended for shipment to Europe
Europe
Europe is, by convention, one of the world's seven continents. Comprising the westernmost peninsula of Eurasia, Europe is generally 'divided' from Asia to its east by the watershed divides of the Ural and Caucasus Mountains, the Ural River, the Caspian and Black Seas, and the waterways connecting...
. Most of the Placerville ore was less than 3% vanadium, too low grade to pay for shipment to Europe, so in 1905 the Vanadium Alloys Co. built an ore-processing mill southeast of Placerville to recover the metal as ferro-vanadium, which it sold. At least five mines were active at one time, and by 1919 the two ore mills at Placerville were producing 30% of the world's vanadium. Through 1940, the mines produced about 3.7 million pounds of vanadium.
Although carnotite
Carnotite
Carnotite is a potassium uranium vanadate radioactive mineral with chemical formula: K222·3H2O. The water content can vary and small amounts of calcium, barium, magnesium, iron, and sodium are often present.-Occurrence:...
was recognized as a minor constituent of the ore since its discovery, the amount was small, and no assays were made of the uranium content of the ore until World War II. Beginning about 1950, the small uranium content of the ore was also recovered from the ore.
Geography
Placerville is located at 38°01′00"N 108°03′14"W (38.016722,-108.053799).See also
- List of cities and towns in Colorado
- San Juan MountainsSan Juan MountainsThe San Juan Mountains are a high and rugged mountain range in the Rocky Mountains in southwestern Colorado. The area is highly mineralized and figured in the gold and silver mining industry of early Colorado. Major towns, all old mining camps, include Creede, Lake City, Silverton, Ouray, and...
- San Juan Skyway National Scenic Byway