By A. H. KOSCHMANN and M. H. BERGENDAHL - USGS 1968
Except for small recoveries of gold by Indians and Spanish explorers, gold was first discovered and mined in the United States in North Carolina in 1799. This initial discovery was followed by others in the 1820's and 1830's in several of the other Appalachian States. These States produced significant amounts of gold until the Civil War. After the discovery of gold in California in 1848, the Western States contributed the bulk of this country's gold production. New discoveries in widely separated areas in the Western States followed in rapid succession.
From 1799 through 1965, the United States produced about 307,182,000 ounces of gold, which at the price of $35 per ounce would be valued in round numbers at $10,751 million. In an analysis of gold-production trends, the period 1932-59 is particularly informative; the effect of the increase of the price of gold in 1934 from $20.67 to $35 per ounce is clearly shown, as is the effect of a fixed selling price of gold combined with rising costs of labor and material in post-World War II years.
Districts that have produced more than 10,000 ounces are distributed in 21 States. Five States - California, Colorado, South Dakota, Alaska, and Nevada - have yielded more than 75 percent of the gold produced in this country. Of the more than 500 districts that have produced more than 10,000 ounces of gold, 45 have produced more than 1 million ounces, and four - Lead, S.D., Cripple Creek, Colo, Grass Valley, Calif., and Bingham, Utah - have produced more than 10 million ounces each. The 25 leading districts have produced about half the gold mined in the United States, and the 508 districts that are described account for roughly 90 to 95 percent.
In general, gold is derived from three types of ore: (1) ore in which gold is the principal metal of value, (2) base-metal ore which yields gold as a byproduct, and (3) placers. In the early years, most of the gold was mined from placers, but after 1873, though placers were by no means depleted and continued to contribute significantly to our annual output, production came chiefly from lode deposits. The search for gold led to the discovery and development of many silver, lead, copper, and zinc deposits from which gold was recovered as a byproduct. Since the late 1930's, byproduct gold has become a significant fraction of the annual domestic gold output.
Most of the gold deposits in the United States are closely associated with and probably genetically related to small batholiths, stocks, and satellitic intrusive bodies of quartz monzonitic composition that range in age from Jurassic to Tertiary. Some deposits, as those in the Southeastern States, may be genetically related to granitic bodies that were intruded at the close of Paleozoic time, and some deposits, as at Jerome, Ariz., are Precambrian in age.
Alaska, the fourth largest gold-producing State, yielded a total of 29,872,981 ounces from the first discovery in 1848 through 1965. More than half of this total was mined from placers in the Yukon region and the Seward Peninsula. The important lode-mining area has been in Southeastern Alaska, where mines' in the Juneau and Chichagof districts produced more than 7 million ounces of gold through 1959.
Arizona ranks eighth among the gold-producing States; a total of about 13,321,000 ounces of gold was mined from 1860 through 1965. Deposits of copper and silver were known long before the Territory was acquired by the United States, but hostile Indians and lack of water discouraged any large-scale prospecting or mining. In the 1870's, after the transcontinental railroads were completed and the Indians ceased hostilities, Arizona's gold deposits received considerable attention. Mining activity increased considerably in the early 1900's, when the large porphyry copper deposits at Ajo, Bisbee, Globe-Miami, Clifton-Morenci, Ray, San Manuel, and Superior were developed. Large-scale mining of these and other copper deposits continues, and most of the gold produced after 1900 has been a byproduct of these ores.
California has produced more gold than any other State - more than 106 million ounces from 1848 through 1965. The well-known discovery in El Dorado County in 1848 sparked a series of gold rushes that indirectly led to colonization of the entire mountain West. The rich gold placers of California yielded phenomenal wealth in the early years, and as the placers were depleted, prospectors searched for and found the source of the placer gold - the high-grade gold-quartz veins of the Mother Lode and Grass Valley. Others explored the forbidding mountain ranges of southern California and found productive lodes in the Cove, Rand, and Sted-man districts. Placer mining was rejuvenated in the early 1900's with the introduction of large bucket dredges. From the late 1930's onward, dredging operations were responsible for a major part of California's gold output.
Colorado ranks second among the gold-producing States; its gold output through 1965 was about 40,776,000 ounces. The first publicized discovery of gold in Colorado was in 1858. The immediate rush to the Denver area resulted in important placer finds near Idaho Springs and Central City. Prospectors ranging far up the Arkansas River valley found gold placers near Leadville as early as 1859. Many rich gold lodes were quickly discovered, and Colorado soon became a major mining area. In the 1870's, important ore discoveries were made in the San Juan Mountains, the Sawatch Mountains, and in the Leadville-Breckenridge area. Gold ore was found in the important Cripple Creek district in 1891.
Idaho, which ranks ninth among the gold-producing States, is credited with producing 8,323,000 ounces of gold from 1863 through 1965. The earliest recorded discovery in Idaho was of placer gold along the Pend Oreille River in 1852. Rich placers were found soon afterward at Pierce City, Elk City, Orofino, Boise Basin, Florence, and Warren, and a brief period of feverish activity followed. By 1870, many of the richer placers were exhausted, and an intensive search for lode deposits resulted. Large-scale dredging rejuvenated the placers, though after 1900, most of Idaho's gold was produced from lode mines.
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