Henderson molybdenum mine
Encyclopedia
The Henderson molybdenum mine is a large underground molybdenum
mine west of the town of Empire
in Clear Creek County, Colorado
, USA. The Henderson mine, which has produced molybdenum since 1976, is owned by Freeport-McMoRan
.
The Henderson mine is North America’s largest producer of primary molybdenum. 2007 production was 40 million pounds of molybdenum, with a value of $1.1 billion.
Production began in 1976, and, on Jan. 4, 2010, the workers mined the billionth pound of molybdenum. In 2006, remaining ore reserves were estimated to be 500 million pounds of recoverable molybdenum.
It was considered by the National Science Foundation
as one of the two final candidates for the Deep Underground Science and Engineering Laboratory
, but lost out to the Homestake Mine
in South Dakota
.
of small veins of molybdenite
in rhyolite
porphyries
of Tertiary
age that intrude into Precambrian
Silver Plume granite
. The ore averages 0.2% molybdenum. The molybdenite is associated with pyrite
and quartz
. The deposit is similar to other porphyry molybdenum deposits such as the Climax mine
in Colorado and the Questa mine in New Mexico
.
The Henderson deposit is located in the Colorado mineral belt, a northeast-southwest alignment of metal deposits that crosses the mountainous part of Colorado from Boulder
to Durango
.
The ore is carried by a 15-mile conveyor belt system through a tunnel beneath the Continental Divide to the ore processing mill near Parshall, Colorado
. The ore is treated by froth flotation
to obtain molybdenite concentrate, which is shipped to a plant in Fort Madison, Iowa
for further processing.
. There is a public parking lot on the Jones Pass Road near the mine, and the National Forest land near the mine is popular year-round for hiking, cross-country skiing, and snowshoeing.
Molybdenum
Molybdenum , is a Group 6 chemical element with the symbol Mo and atomic number 42. The name is from Neo-Latin Molybdaenum, from Ancient Greek , meaning lead, itself proposed as a loanword from Anatolian Luvian and Lydian languages, since its ores were confused with lead ores...
mine west of the town of Empire
Empire, Colorado
The historic Town of Empire is a Statutory Town located in Clear Creek County, Colorado, United States. The population was 355 at the U.S. Census 2000. The town is a former mining settlement that flourished during the Colorado Silver Boom in the late 19th century. It is located in the valley Clear...
in Clear Creek County, Colorado
Clear Creek County, Colorado
Clear Creek County is one of the 64 counties of the state of Colorado of the United States. The county population was 9,322 at U.S. Census 2000. The county seat is Georgetown...
, USA. The Henderson mine, which has produced molybdenum since 1976, is owned by Freeport-McMoRan
Freeport-McMoRan
Freeport-McMoRan Copper & Gold Inc., often called simply Freeport, is the world's lowest-cost copper producer and one of the world's largest producers of gold...
.
The Henderson mine is North America’s largest producer of primary molybdenum. 2007 production was 40 million pounds of molybdenum, with a value of $1.1 billion.
History
The Henderson mine is near the Urad mine, which produced molybdenum from 1914 to the 1960s, before exhausting its orebody. The owner, Climax Molybdenum Co., recognized the potential for deeper orebodies in the area, and discovered the Henderson deposit in 1964. The mine was named after mining engineer Robert Henderson.Production began in 1976, and, on Jan. 4, 2010, the workers mined the billionth pound of molybdenum. In 2006, remaining ore reserves were estimated to be 500 million pounds of recoverable molybdenum.
It was considered by the National Science Foundation
National Science Foundation
The National Science Foundation is a United States government agency that supports fundamental research and education in all the non-medical fields of science and engineering. Its medical counterpart is the National Institutes of Health...
as one of the two final candidates for the Deep Underground Science and Engineering Laboratory
Deep Underground Science and Engineering Laboratory
The Deep Underground Science and Engineering Laboratory, or DUSEL is a major project under consideration by the National Science Foundation. DUSEL will be a series of large laboratories, caverns, and cleanrooms serving the field of underground science...
, but lost out to the Homestake Mine
Homestake Mine (South Dakota)
The Homestake Mine was a deep underground gold mine located in Lead, South Dakota. Until it closed in 2002 it was the largest and deepest gold mine in North America, producing more than 40 million ounces of gold. The Homestake Mine is famous in scientific circles for being the site at which the...
in South Dakota
South Dakota
South Dakota is a state located in the Midwestern region of the United States. It is named after the Lakota and Dakota Sioux American Indian tribes. Once a part of Dakota Territory, South Dakota became a state on November 2, 1889. The state has an area of and an estimated population of just over...
.
Geology
The deposit is a porphyry-type deposit consisting of a stockworkStockwork
In geology, a stockwork is a complex system of structurally controlled or randomly oriented veins. Stockworks are common in many ore deposit types and especially notable in greisens. They are also referred to as stringer zones....
of small veins of molybdenite
Molybdenite
Molybdenite is a mineral of molybdenum disulfide, MoS2. Similar in appearance and feel to graphite, molybdenite has a lubricating effect that is a consequence of its layered structure. The atomic structure consists of a sheet of molybdenum atoms sandwiched between sheets of sulfur atoms...
in rhyolite
Rhyolite
This page is about a volcanic rock. For the ghost town see Rhyolite, Nevada, and for the satellite system, see Rhyolite/Aquacade.Rhyolite is an igneous, volcanic rock, of felsic composition . It may have any texture from glassy to aphanitic to porphyritic...
porphyries
Porphyry (geology)
Porphyry is a variety of igneous rock consisting of large-grained crystals, such as feldspar or quartz, dispersed in a fine-grained feldspathic matrix or groundmass. The larger crystals are called phenocrysts...
of 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...
age that intrude into Precambrian
Precambrian
The Precambrian is the name which describes the large span of time in Earth's history before the current Phanerozoic Eon, and is a Supereon divided into several eons of the geologic time scale...
Silver Plume granite
Granite
Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...
. The ore averages 0.2% molybdenum. The molybdenite is associated with 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 quartz
Quartz
Quartz is the second-most-abundant mineral in the Earth's continental crust, after feldspar. It is made up of a continuous framework of SiO4 silicon–oxygen tetrahedra, with each oxygen being shared between two tetrahedra, giving an overall formula SiO2. There are many different varieties of quartz,...
. The deposit is similar to other porphyry molybdenum deposits such as the Climax mine
Climax mine
The Climax mine, located in Climax, Colorado, United States, was a major molybdenum mine in Lake and Summit counties, Colorado. In its heyday, the Climax mine was the largest molybdenum mine in the world, and for many years it supplied three-fourths of the world's supply of molbdenum...
in Colorado and the Questa mine in New Mexico
New Mexico
New Mexico is a state located in the southwest and western regions of the United States. New Mexico is also usually considered one of the Mountain States. With a population density of 16 per square mile, New Mexico is the sixth-most sparsely inhabited U.S...
.
The Henderson deposit is located in the Colorado mineral belt, a northeast-southwest alignment of metal deposits that crosses the mountainous part of Colorado from Boulder
Boulder, Colorado
Boulder is the county seat and most populous city of Boulder County and the 11th most populous city in the U.S. state of Colorado. Boulder is located at the base of the foothills of the Rocky Mountains at an elevation of...
to Durango
Durango, Colorado
The City of Durango is a Home Rule Municipality that is the county seat and the most populous city of La Plata County, Colorado, United States. The United States Census Bureau said that the city population was 16,887 in 2010 census.-History:...
.
Mining
Mining is done by block caving. In 1980 the cavity produced by the block caving broke through to the surface, producing a large glory hole on the side of Red Mountain.The ore is carried by a 15-mile conveyor belt system through a tunnel beneath the Continental Divide to the ore processing mill near Parshall, Colorado
Parshall, Colorado
Parshall is an unincorporated town and a U.S. Post Office in Grand County, Colorado, United States. It is located along the south side of U.S. Route 40 between Hot Sulphur Springs and Kremmling, on the north bank of the Colorado River downstream from Byers Canyon. The community consists of a...
. The ore is treated by froth flotation
Froth flotation
Froth flotation is a process for selectively separating hydrophobic materials from hydrophilic. This is used in several processing industries...
to obtain molybdenite concentrate, which is shipped to a plant in Fort Madison, Iowa
Fort Madison, Iowa
Fort Madison, situated on the Mississippi River, is a city in and one of the county seats of Lee County, Iowa, United States. The other county seat is Keokuk. The population was 10,715 at the 2000 census...
for further processing.
Location
The Henderson mine is located at 39°46′13"N 105°51′06"W at an elevation of about 10,300 feet, about 1.6 miles east of the Continental Divide. It is approximately 9 miles west of Empire, Colorado.Outdoor recreation
The Henderson mine is on private land. However, the mine is surrounded by US Forest Service land of the Arapaho National ForestArapaho National Forest
Arapaho National Forest is a National Forest located in north-central Colorado, United States. The facility is managed jointly with the Roosevelt National Forest and the Pawnee National Grassland from the United States Forest Service office in Fort Collins, Colorado...
. There is a public parking lot on the Jones Pass Road near the mine, and the National Forest land near the mine is popular year-round for hiking, cross-country skiing, and snowshoeing.