Intermountain West - Mining
In the late 19th century, gold miners followed shortly on the heels of the Mormons to become the second largest group of settlers in the region. The discovery of the Comstock Lode in Nevada gave rise to Virginia City, which grew into a city of 20,000 during its heyday around 1870 before nearly disappearing with the decline of high-quality ore.
The boom in gold and silver mining in the years immediately following the Comstock discovery created rapid population growth in Nevada. This culminated in the admission of the state into the union in 1864, long before most of its neighbors. The depletion of much of this mineral resource by the late 19th century resulted in a widespread population decline in Nevada, one from which it did not fully recover until well into the 20th century. Today, the mining economy is of little significance to the state--or to any part of the interior West--although some of the abandoned mining centers are important tourist attractions.
Leading today's list of mineral contributions to the region's economy is copper, with production concentrated in Arizona and Utah. The vast open pit of the Bingham mine outside Salt Lake City, said to be the largest human-made excavation in the world, has yielded some 8 million tons of copper. Among the several score major and minor copper-mining centers in Arizona, the most important is at Morenci in the eastern part of the state. Other important mines are at San Manuel, Globe, and Bisbee, all in southern Arizona.
Most of the copper ore mined in the Intermountain West is low grade, with a metal content of under 5 percent. Consequently, most mines have a smelting or concentrating facility located nearby to lessen shipment costs by greatly reducing the weight of the material being shipped. Refining is thus a major manufacturing industry in the region.
Lead and zinc follow copper in regional importance, with the two often joined by several other metals mined at the same location. The Butte Hill mine in Montana, for example, long was a significant producer of lead and zinc as well as copper. The Coeur d'Alene district in northern Idaho produces gold, silver, lead, and zinc; the Leadville district in Colorado has those four plus molybdenum, used in the manufacture of steel products. In fact, some three-quarters of the world's supply of molybdenum comes from the Leadville district. Uranium exploration has also been widespread in the region, and today Utah and Colorado are the principal producing states. Approximately 25 million tons of coal is mined annually.
Spread across thousands of square kilometers of the area where Utah, Colorado, and Wyoming meet are the vast oil shale deposits of the Green River Formation. Locked in these rocks are as much as a trillion barrels of oil, vastly more than the entire proven alternative oil reserves of the world. However, operational and environmental problems have put development of this industry largely on hold.
There has been little sustained or substantial urban growth based on these mineral resources. Butte, Montana, with a population of 34,000 in 1990, is perhaps the region's largest city developed with mining (copper) as the main base of the economy, yet it has long been an important processing center for agricultural products as well.
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