Silver mining in Colorado
Encyclopedia
Silver mining in Colorado, a state of the United States has taken place since the 1860s. In the past, Colorado
called itself the Silver state. (Nevada
also calls itself the Silver state; in reality, the US state which has produced the most silver is Idaho
.)
-Idaho Springs
district a short time after lode gold was discovered in 1859. However, mining the silver veins was delayed for the most part until smelters were built in the late 1860s. The veins of the district are zoned in a roughly concentric manner, with gold-bearing pyrite veins in the center, and silver-bearing galena veins more common in the outlying areas.
in 1864. The discovery led to others in the Montezuma district, including those at Saints John
.
in 1859. Silver, the main product from the district, was not discovered until 1864.
See Leadville mining district
Despite the early silver discoveries, Colorado’s largest silver district, Leadville
was not discovered until 1874. Leadville was the largest silver-producing district in Colorado. Cumulative production through 1963 was 240 million troy ounces of silver, 3 million troy ounces of gold, 987 million metric tons of lead, 712 million metric tons of zinc, and 48 million metric tons of copper.
were led to the Aspen
area by geological maps that showed outcrops of Leadville Limestone. They found silver ore on Aspen Mountain, but ore production was small until the Denver and Rio Grande Railroad reached the town in 1887 and provided economic shipment of ore to smelters. Ore occurs in the Mississippian Leadville Limestone and the lower part of the overlying Pennsylvanian
Belden Formation. Ore minerals include galena
, sphalerite
, and native silver. Early production was almost all silver, but after 1900, lead and zinc became economically important. Major mining operations continued until 1952. Total production was 101 million troy ounces of silver
, 294 tons of lead, and 11,000 tons of zinc
.
mining district in 1878 or 1879. As they reached the deeper sulfide
ores, the miners found that the ore contained so much zinc that the smelters refused to buy it. A roaster and magnetic separator were installed in 1905 to separate out the zinc minerals, turning the problem into an asset. The mining operations transitioned increasingly to zinc, although the Eagle Mine was still the leading producer of silver in the state in 1930. The New Jersey Zinc Company
entered Gilman in 1912, and over a period of years bought all the principal mines and the entire townsite. Zinc
was the economic mainstay until 1931, when low zinc
prices forced the company to switch to mining copper
-silver
ores. Production of the district through 1964 was 64 million troy ounces (1,990 metric tons) of silver
, 348,000 ounces (10.82 metric tons) of gold
, 578,000 metric tons of zinc
, 114,000 metric tons of lead, and 92,000 metric tons of copper
. Zinc production resumed in 1941, and remained the principal product of the mines until they were closed in the 1980s.
district in Mineral County
was discovered in 1887, but did not become a significant silver producer until 1891. The ore occurs as veins along north-south trending faults, and as replacement bodies in the Creede Formation, a Tertiary
ash-flow tuff
. Ore minerals are sphalerite
, galena
, acanthite
, native silver, pyrite
and chalcopyrite
. Production through 1983 totaled 80 million ounces (2,490 metric tons) of silver, 150 thousand ounces (4.7 metric tons) of gold, and considerable lead and zinc.
is as a byproduct of gold mining at the Cripple Creek & Victor Gold Mine
, a large open-pit heap leach operation owned by AngloGold Ashanti
at Victor, Colorado
(see Cripple Creek mining district). In 2006, the mine produced 4.0 metric tons (130,000 ounces) of silver.
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...
called itself the Silver state. (Nevada
Nevada
Nevada is a state in the western, mountain west, and southwestern regions of the United States. With an area of and a population of about 2.7 million, it is the 7th-largest and 35th-most populous state. Over two-thirds of Nevada's people live in the Las Vegas metropolitan area, which contains its...
also calls itself the Silver state; in reality, the US state which has produced the most silver is Idaho
Idaho
Idaho is a state in the Rocky Mountain area of the United States. The state's largest city and capital is Boise. Residents are called "Idahoans". Idaho was admitted to the Union on July 3, 1890, as the 43rd state....
.)
Central City-Idaho Springs district
Silver veins were discovered in the Central CityCentral City, Colorado
Central City is a home rule municipality in Clear Creek and Gilpin counties in the U.S. state of Colorado, and the county seat of Gilpin County. The city population was 515 in the 2000 United States Census...
-Idaho Springs
Idaho Springs, Colorado
The City of Idaho Springs is a municipality in the U.S. state of Colorado that is the most populous settlement in Clear Creek County, Colorado. Idaho Springs is located in Clear Creek Canyon, in the mountains upstream from Golden, some thirty miles west of Denver...
district a short time after lode gold was discovered in 1859. However, mining the silver veins was delayed for the most part until smelters were built in the late 1860s. The veins of the district are zoned in a roughly concentric manner, with gold-bearing pyrite veins in the center, and silver-bearing galena veins more common in the outlying areas.
Montezuma district
The first silver discovery in Colorado was a mile south of MontezumaMontezuma, Colorado
The Town of Montezuma is a Statutory Town located in eastern Summit County, Colorado, United States. The town population was 42 at U.S. Census 2000. The town is a former mining camp that sits at an elevation of , just west of the Continental Divide, nestled among mountains that reach an elevation...
in 1864. The discovery led to others in the Montezuma district, including those at Saints John
Saints John, Colorado
Saints John, originally called Coleyville, is a former silver-mining town in Summit County, Colorado, USA. About a mile from the town of Montezuma, Saints John was the site of one of the first silver discoveries in Colorado...
.
Argentine district
The discovery of silver in the Montezuma district led to the silver discovery at the Belmont lode in the Argentine district just northeast of the Montezuma district.Georgetown-Silver Plume district
Prospectors found gold veins near present GeorgetownGeorgetown, Colorado
The historic town of Georgetown is a Territorial Charter Municipality that is the county seat of Clear Creek County, Colorado, United States. The former silver mining camp along Clear Creek in the Front Range of the Rocky Mountains was established in 1859 during the Pike's Peak Gold Rush...
in 1859. Silver, the main product from the district, was not discovered until 1864.
Leadville district
Leadville mining district
The Leadville mining district was the most productive silver-mining district in the US state of Colorado. It is located immediately east of the town of Leadville....
Despite the early silver discoveries, Colorado’s largest silver district, Leadville
Leadville, Colorado
Leadville is a Statutory City that is the county seat of, and the only municipality in, Lake County, Colorado, United States. Situated at an elevation of , Leadville is the highest incorporated city and the second highest incorporated municipality in the United States...
was not discovered until 1874. Leadville was the largest silver-producing district in Colorado. Cumulative production through 1963 was 240 million troy ounces of silver, 3 million troy ounces of gold, 987 million metric tons of lead, 712 million metric tons of zinc, and 48 million metric tons of copper.
Aspen district
In 1879, prospectors searching for another LeadvilleLeadville, Colorado
Leadville is a Statutory City that is the county seat of, and the only municipality in, Lake County, Colorado, United States. Situated at an elevation of , Leadville is the highest incorporated city and the second highest incorporated municipality in the United States...
were led to the Aspen
Aspen, Colorado
The City of Aspen is a Home Rule Municipality that is the county seat and the most populous city of Pitkin County, Colorado, United States. The United States Census Bureau estimates that the city population was 5,804 in 2005...
area by geological maps that showed outcrops of Leadville Limestone. They found silver ore on Aspen Mountain, but ore production was small until the Denver and Rio Grande Railroad reached the town in 1887 and provided economic shipment of ore to smelters. Ore occurs in the Mississippian Leadville Limestone and the lower part of the overlying Pennsylvanian
Pennsylvanian
The Pennsylvanian is, in the ICS geologic timescale, the younger of two subperiods of the Carboniferous Period. It lasted from roughly . As with most other geochronologic units, the rock beds that define the Pennsylvanian are well identified, but the exact date of the start and end are uncertain...
Belden Formation. Ore minerals include galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...
, sphalerite
Sphalerite
Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides...
, and native silver. Early production was almost all silver, but after 1900, lead and zinc became economically important. Major mining operations continued until 1952. Total production was 101 million troy ounces of silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, 294 tons of lead, and 11,000 tons of zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
.
Gilman district
Silver was discovered in the GilmanGilman, Colorado
Gilman is an abandoned mining town in southeastern Eagle County, Colorado, United States. The U.S. Post Office at Minturn now serves Gilman postal addresses....
mining district in 1878 or 1879. As they reached the deeper sulfide
Sulfide
A sulfide is an anion of sulfur in its lowest oxidation state of 2-. Sulfide is also a slightly archaic term for thioethers, a common type of organosulfur compound that are well known for their bad odors.- Properties :...
ores, the miners found that the ore contained so much zinc that the smelters refused to buy it. A roaster and magnetic separator were installed in 1905 to separate out the zinc minerals, turning the problem into an asset. The mining operations transitioned increasingly to zinc, although the Eagle Mine was still the leading producer of silver in the state in 1930. The New Jersey Zinc Company
New Jersey Zinc Company
The Horsehead Corporation , formerly the New Jersey Zinc Company, is an American producer of zinc and related materials.The New Jersey Zinc Company was for many years the largest producer of zinc and zinc products in the United States. The company thrived in the period from 1897 to 1966, at which...
entered Gilman in 1912, and over a period of years bought all the principal mines and the entire townsite. Zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
was the economic mainstay until 1931, when low zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
prices forced the company to switch to mining copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
-silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
ores. Production of the district through 1964 was 64 million troy ounces (1,990 metric tons) of silver
Silver
Silver is a metallic chemical element with the chemical symbol Ag and atomic number 47. A soft, white, lustrous transition metal, it has the highest electrical conductivity of any element and the highest thermal conductivity of any metal...
, 348,000 ounces (10.82 metric tons) of 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...
, 578,000 metric tons of zinc
Zinc
Zinc , or spelter , is a metallic chemical element; it has the symbol Zn and atomic number 30. It is the first element in group 12 of the periodic table. Zinc is, in some respects, chemically similar to magnesium, because its ion is of similar size and its only common oxidation state is +2...
, 114,000 metric tons of lead, and 92,000 metric tons of copper
Copper
Copper is a chemical element with the symbol Cu and atomic number 29. It is a ductile metal with very high thermal and electrical conductivity. Pure copper is soft and malleable; an exposed surface has a reddish-orange tarnish...
. Zinc production resumed in 1941, and remained the principal product of the mines until they were closed in the 1980s.
Creede district
The CreedeCreede, Colorado
The historic town of Creede is a Statutory Town that is the county seat of, and the only incorporated municipality in, Mineral County, Colorado, United States. The town population was 377 at the U.S. Census 2000.-History:...
district in Mineral County
Mineral County, Colorado
Mineral County is the second least populous of the 64 counties of the State of Colorado of the United States. The county was named for the many valuable minerals found in the mountains and streams of the area. The county population was 831 at U.S. Census 2000...
was discovered in 1887, but did not become a significant silver producer until 1891. The ore occurs as veins along north-south trending faults, and as replacement bodies in the Creede Formation, a Tertiary
Tertiary
The Tertiary is a deprecated term for a geologic period 65 million to 2.6 million years ago. The Tertiary covered the time span between the superseded Secondary period and the Quaternary...
ash-flow tuff
Tuff
Tuff is a type of rock consisting of consolidated volcanic ash ejected from vents during a volcanic eruption. Tuff is sometimes called tufa, particularly when used as construction material, although tufa also refers to a quite different rock. Rock that contains greater than 50% tuff is considered...
. Ore minerals are sphalerite
Sphalerite
Sphalerite is a mineral that is the chief ore of zinc. It consists largely of zinc sulfide in crystalline form but almost always contains variable iron. When iron content is high it is an opaque black variety, marmatite. It is usually found in association with galena, pyrite, and other sulfides...
, galena
Galena
Galena is the natural mineral form of lead sulfide. It is the most important lead ore mineral.Galena is one of the most abundant and widely distributed sulfide minerals. It crystallizes in the cubic crystal system often showing octahedral forms...
, acanthite
Acanthite
Acanthite, Ag2S, crystallizes in the monoclinic system and is the stable form of silver sulfide below 173 °C. Argentite is the stable form above that temperature. As argentite cools below that temperature its cubic form is distorted to the monoclinic form of acanthite. Below 173 °C...
, native silver, pyrite
Pyrite
The mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS2. This mineral's metallic luster and pale-to-normal, brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold...
and chalcopyrite
Chalcopyrite
Chalcopyrite is a copper iron sulfide mineral that crystallizes in the tetragonal system. It has the chemical composition CuFeS2. It has a brassy to golden yellow color and a hardness of 3.5 to 4 on the Mohs scale. Its streak is diagnostic as green tinged black.On exposure to air, chalcopyrite...
. Production through 1983 totaled 80 million ounces (2,490 metric tons) of silver, 150 thousand ounces (4.7 metric tons) of gold, and considerable lead and zinc.
Current production
The largest current source of silver in ColoradoColorado
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...
is as a byproduct of gold mining at the Cripple Creek & Victor Gold Mine
Cripple Creek & Victor Gold Mine
The Cripple Creek & Victor Gold Mine, formerly and historically Cresson Mine, is a gold mine located near the town of Victor, in the Cripple Creek mining district in the US state of Colorado. It is the largest current producer of gold in Colorado...
, a large open-pit heap leach operation owned by AngloGold Ashanti
AngloGold Ashanti
AngloGold Ashanti Limited is a global gold mining company. It was formed in 2004 by the merger of AngloGold and the Ashanti Goldfields Corporation.AngloGold Ashanti Limited is now a global gold producer with 21 operations on four continents...
at Victor, Colorado
Victor, Colorado
Victor is a Statutory City in Teller County, Colorado, United States. The population was 445 at the 2000 census.Victor is in the heart of Colorado's gold country, home to two of the major gold mines in the Cripple Creek mining district...
(see Cripple Creek mining district). In 2006, the mine produced 4.0 metric tons (130,000 ounces) of silver.
See also
- Champion MillChampion MillChampion Mill, in Lake County, Colorado, is part of a mining complex on the eastern slope of Mount Champion on Halfmoon Creek. Established in the 1890s, it was a consistent supplier of gold and silver, as well as galena and pyrite to the smelters in Leadville, CO...
- Coal mining in ColoradoCoal mining in ColoradoEarly coal mining in Colorado, a state of the United States was spread across the state. Some early coal mining areas are currently inactive, including the Denver Basin Raton Basin coal fields along the Front Range...
- Gold mining in ColoradoGold mining in ColoradoOn 1859-05-06, John H. Gregory found a gold-bearing vein in Gregory Gulch between Black Hawk and Central City. Within two months many other veins were discovered, including the Bates, Gunnell, Kansas, and Burroughs...
- Silver miningSilver miningSilver mining refers to the resource extraction of the precious metal element silver by mining.-History:Silver has been known since ancient times. It is mentioned in the Book of Genesis, and slag heaps found in Asia Minor and on the islands of the Aegean Sea indicate that silver was being separated...
- Silver mining in the United StatesSilver mining in the United StatesSilver mining in the United States began on a major scale with the discovery of the Comstock Lode in Nevada in 1858. The industry suffered greatly from the demonetization of silver in 1873 by the "Crime of 73," but silver mining continues today....
- Uranium mining in ColoradoUranium mining in ColoradoUranium mining in Colorado, United States, goes back to 1872, when pitchblende ore was taken from gold mines near Central City, Colorado. The Colorado uranium industry has seen booms and busts, but continues to this day...