Mother lode is a principal vein or zone of gold or silver ore. The term is also used colloquially to refer to the real or imaginary origin of something valuable or in great abundance.
The term probably came from a literal translation of the Spanish veta madre, a term common in old Mexican mining. Veta madre, for instance, is the name given to an 11-kilometre-long (6.8 mi) silver vein discovered in 1548 in Guanajuato, New Spain (modern-day Mexico). [1]
In the United States, Mother Lode is most famously the name given to a long alignment of hard-rock gold deposits stretching northwest-southeast in the Sierra Nevada of California, [2] bounded on the east by the Melones Fault Zone. [3] It was discovered in the early 1850s, during the California gold rush. The California Mother Lode is a zone from 1.5 to 6 kilometres (0.93 to 3.73 mi) wide and 190 kilometres (120 mi) long, between Georgetown on the north and Mormon Bar on the south.
The Mother Lode coincides with the suture line of a terrane, the Smartville Block. [4] The zone contains hundreds of mines and prospects, including some of the best-known historic mines of the gold-rush era. Individual gold deposits within the Mother Lode are gold-bearing quartz veins up to 15 metres (49 ft) thick and a few thousand feet long. The California Mother Lode was one of the most productive gold-producing districts in the United States. Now it is known as a destination for tourism and for its vineyards. [5]
As with most gold rushes, the California gold rush started with the discovery of placer gold in sands and gravels of streambeds, where the gold had eroded from hard-rock vein deposits. Placer miners followed the gold-bearing sands upstream to discover the source in the bedrock. This source was the "mother" of the gold in the river and so was dubbed the "mother lode".
The term "mother lode" has appeared in some pop culture. For example:
Placer mining is the mining of stream bed (alluvial) deposits for minerals. This may be done by open-pit or by various surface excavating equipment or tunneling equipment.
The General Mining Act of 1872 is a United States federal law that authorizes and governs prospecting and mining for economic minerals, such as gold, platinum, and silver, on federal public lands. This law, approved on May 10, 1872, codified the informal system of acquiring and protecting mining claims on public land, formed by prospectors in California and Nevada from the late 1840s through the 1860s, such as during the California Gold Rush. All citizens of the United States of America 18 years or older have the right under the 1872 mining law to locate a lode or placer (gravel) mining claim on federal lands open to mineral entry. These claims may be located once a discovery of a locatable mineral is made. Locatable minerals include but are not limited to platinum, gold, silver, copper, lead, zinc, uranium and tungsten.
In geology, a lode is a deposit of metalliferous ore that fills or is embedded in a fracture in a rock formation or a vein of ore that is deposited or embedded between layers of rock. The current meaning dates from the 17th century, being an expansion of an earlier sense of a "channel, watercourse" in Late Middle English, which in turn is from the 11th-century meaning of lode as a "course, way".
The Comstock Lode is a lode of silver ore located under the eastern slope of Mount Davidson, a peak in the Virginia Range in Virginia City, Nevada, which was the first major discovery of silver ore in the United States and named after American miner Henry Comstock.
The Smartville Block, also called the Smartville Ophiolite, Smartville Complex, or Smartville Intrusive Complex, is a geologic terrane formed in the ocean from a volcanic island arc that was accreted onto the North American Plate during the late Jurassic. The collision created sufficient crustal heating to drive mineral-laden water up through numerous fissures along the contact zone. When these cooled, among the precipitating minerals was gold. Associated with the Western Metamorphic Belt of the Sierra Nevada foothills it extends from the central Sierra Nevada mountain range, due west, under a section of the Central Valley and California Coast Ranges, in northern California. The ophiolitic sequence found in this terrane is one of several major ophiolites found in California. Ophiolites are crustal and upper-mantle rocks from the ocean floor that have been moved on land. Ophiolites have been studied extensively regarding the movement of crustal rocks by plate tectonics.
Silver mining is the extraction of silver from minerals, starting with mining. Because silver is often found in intimate combination with other metals, its extraction requires elaborate technologies. In 2008, ca. 25,900 metric tons were consumed worldwide, most of which came from mining.
Gold became highly concentrated in California, United States as the result of global forces operating over hundreds of millions of years. Volcanoes, tectonic plates and erosion all combined to concentrate billions of dollars' worth of gold in the mountains of California. During the California Gold Rush, gold-seekers known as "Forty-Niners" retrieved this gold, at first using simple techniques, and then developing more sophisticated techniques, which spread around the world.
In the United States, gold mining has taken place continually since the discovery of gold at the Reed farm in North Carolina in 1799. The first documented occurrence of gold was in Virginia in 1782. Some minor gold production took place in North Carolina as early as 1793, but created no excitement. The discovery on the Reed farm in 1799 which was identified as gold in 1802 and subsequently mined marked the first commercial production.
Silver 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 Coinage Act of 1873, known pejoratively as the "Crime of 73", but silver mining continues today.
Gold mining in Colorado, a state of the United States, has been an industry since 1858. It also played a key role in the establishment of the state of Colorado.
Silver mining in Colorado has taken place since the 1860s. In the past, Colorado called itself the Silver State.
Silver mining in Nevada, a state of the United States, began in 1858 with the discovery of the Comstock Lode, the first major silver-mining district in the United States. Nevada calls itself the "Silver State." Nevada is the nation's second-largest producer of silver, after Alaska. In 2014 Nevada produced 10.93 million troy ounces of silver, of which 6.74 million ounces were as a byproduct of the mining of gold. The largest byproducers were the Hycroft Mine, the Phoenix Mine, the Midas Mine and Round Mountain.
Gold mining in Alaska, a state of the United States, has been a major industry and impetus for exploration and settlement since a few years after the United States acquired the territory in 1867 from the Russian Empire. Russian explorers discovered placer gold in the Kenai River in 1848, but no gold was produced. Gold mining started in 1870 from placers southeast of Juneau, Alaska.
The Leadville mining district, located in the Colorado Mineral Belt, was the most productive silver-mining district in the state of Colorado and hosts one of the largest lead-zinc-silver deposits in the world. Oro City, an early Colorado gold placer mining town located about a mile east of Leadville in California Gulch, was the location to one of the richest placer gold strikes in Colorado, with estimated gold production of 120,000–150,000 ozt, worth $2.5 to $3 million at the then-price of $20.67 per troy ounce.
The Nome mining district, also known as the Cape Nome mining district, is a gold mining district in the U.S. state of Alaska. It was discovered in 1898 when Erik Lindblom, Jafet Lindeberg and John Brynteson, the "Three Lucky Swedes", found placer gold deposits on Anvil Creek and on the Snake River few miles from the future site of Nome. Word of the strike caused a major gold rush to Nome in the spring of 1899.
The Willow Creek mining district, also known as the Independence Mine/Hatcher Pass district, is a gold-mining area in the U.S. state of Alaska. Underground hard-rock mining of gold from quartz veins accounts for most of the mineral wealth extracted from the Hatcher Pass area. The first mining efforts were placer mining of stream gravels, and placer mining in the area has continued sporadically to this day. Robert Hatcher discovered gold and staked the first claim in the Willow Creek valley in September 1906. The first lode mill in the area started operating in 1908. Underground mining continued at a variety of locations around the pass until 1951. In the 1980s one of the area's hard-rock mines was briefly re-opened. At least one mining company is actively exploring for gold in the area now. Through 2006 the district produced 667-thousand ounces of hard rock gold and 60-thousand ounces of placer gold.
Mother Lode is a 1982 adventure thriller film directed by and starring Charlton Heston. It was written and produced by his son Fraser Clarke Heston. The film also stars Nick Mancuso and Kim Basinger as a gold-hunting couple.
Gold Hill is an unincorporated community in Placer County, California. Gold Hill is located 6 miles (9.7 km) west of Auburn. It lies at an elevation of 354 feet.
The Juneau gold belt is located in the southeastern portion of the U.S. state of Alaska. This belt is approximately 100 miles (160 km) in length, north/northwest-trending, and extends from Berners Bay southeastward to Windham Bay, 60 miles (97 km) southeast of Juneau, and includes Douglas Island. The belt contains over 200 gold-quartz-vein deposits with production nearing 7,000,000 ounces (200,000,000 g) of gold. More than three-quarters of Alaska's lode gold was mined from the Juneau gold belt.
A mother lode is a principal vein or zone of veins of gold or silver ore.
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