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Leadville Mining District
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 , worth $2.5 to $3 million at the then-price of $20.67 per troy ounce. Cumulative production through 1963 was of silver, of gold, of lead, of zinc, and of copper. The district also produced byproduct bismuth, and iron-manganese ore. History Gold was discovered in the area in late 1859, during the Pike's Peak Gold Rush. However the initial discovery, where California Gulch empties into the Arkansas River, was not rich enough to cause excitement. On April 26, 1860, Abe Lee made a rich discovery of placer gold in California Gulch, about a mile ea ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Park City
Park City may refer to: a city in Utah. Places * National Park City, London, England, UK; see parks and open spaces in London in the United States * Park City, Illinois * Park City, Kansas * Park City, Kentucky * Park City, Montana * Park City, Tennessee * Park City, Utah * Park City Historic District, a residential historic district in Amasa, Michigan Facilities and structures * Park City Center (Sofia), Bulgaria; a shopping centre in the United States * Park City Plaza, Bridgeport, Connecticut, USA; an office building * Park City Center, Lancaster, Pennsylvania, USA; a shopping center * Park City Hospital, Utah, USA; see List of hospitals in Utah * Park City Branch, Salt Lake City, Utah, USA; a rail division * Park City Mountain Resort, Park City, Utah, USA; a ski resort * Park City High School, Park City, Utah, USA Other uses * MV ''Park City'', a ferry * ''Park City'' (short story collection) by Ann Beattie * ''Park City Daily News'', Bowling Green, Kentucky, USA; a ne ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Placer Deposits
In geology, a placer deposit or placer is an accumulation of valuable minerals formed by gravity separation from a specific source rock during sedimentary processes. The name is from the Spanish word ''placer'', meaning "alluvial sand". Placer mining is an important source of gold, and was the main technique used in the early years of many gold rushes, including the California Gold Rush. Types of placer deposits include alluvium, eluvium, beach placers, aeolian placers and paleo-placers. Placer materials must be both dense and resistant to weathering processes. To accumulate in placers, mineral particles must have a specific gravity above 2.58. Placer environments typically contain black sand, a conspicuous shiny black mixture of iron oxides, mostly magnetite with variable amounts of ilmenite and hematite. Valuable mineral components often occurring with black sands are monazite, rutile, zircon, chromite, wolframite, and cassiterite. Early mining operations were likely a result ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Colorado Silver Boom
The Colorado Silver Boom was a dramatic expansionist period of silver mining activity in the U.S. state of Colorado in the late 19th century. The boom started in 1879 with the discovery of silver at Leadville. Over 82 million dollars worth of silver was mined during the period, making it the second great mineral boom in the state, and coming 20 years after the earlier and shorter Colorado Gold Rush of 1859. The boom was largely the consequence of large-scale purchases of silver by the United States Government authorized by Congress in 1878. The boom endured throughout the 1880s, resulting in an intense increase in both the population and wealth of Colorado, especially in the mountains. It came to an end in 1893 in the wake of the collapse of silver prices caused by the repeal of Sherman Silver Purchase Act.Voynick, S.M., 1992, Colorado Gold, Missoula: Mountain Press Publishing Company, Silver had been discovered in Colorado in the 1860s, with early mining in Clear Creek Canyon at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lode
In geology, a lode is a deposit of metalliferous ore that fills or is embedded in a fissure (or crack) in a rock formation or a vein of ore that is deposited or embedded between layers of rock. The current meaning (ore vein) 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 generally accepted hydrothermal model of lode deposition posits that metals dissolved in hydrothermal solutions (hot spring fluids) deposit the gold or other metallic minerals inside the fissures in the pre-existing rocks. Lode deposits are distinguished primarily from placer deposits, where the ore has been eroded out from its original depositional environment and redeposited by sedimentation. A third process for ore deposition is as an evaporite. A stringer lode is one in which the rock is so permeated by small veinlets that rather than mining the v ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cerussite
Cerussite (also known as lead carbonate or white lead ore) is a mineral consisting of lead carbonate (PbCO3), and is an important ore of lead. The name is from the Latin ''cerussa'', white lead. ''Cerussa nativa'' was mentioned by Conrad Gessner in 1565, and in 1832 F. S. Beudant applied the name ''céruse'' to the mineral, whilst the present form, cerussite, is due to W. Haidinger (1845). Miners' names in early use were lead-spar and white-lead-ore. Cerussite crystallizes in the orthorhombic crystal system and is isomorphous with aragonite. Like aragonite it is very frequently twinned, the compound crystals being pseudo-hexagonal in form. Three crystals are usually twinned together on two faces of the prism, producing six-rayed stellate groups with the individual crystals intercrossing at angles of nearly 60°. Crystals are of frequent occurrence and they usually have very bright and smooth faces. The mineral also occurs in compact granular masses, and sometimes in fibrous fo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead (metal)
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cut, lead is a shiny gray with a hint of blue. It tarnishes to a dull gray color when exposed to air. Lead has the highest atomic number of any stable element and three of its isotopes are endpoints of major nuclear decay chains of heavier elements. Lead is toxic, even in small amounts, especially to children. Lead is a relatively unreactive post-transition metal. Its weak metallic character is illustrated by its amphoteric nature; lead and lead oxides react with acids and bases, and it tends to form covalent bonds. Compounds of lead are usually found in the +2 oxidation state rather than the +4 state common with lighter members of the carbon group. Exceptions are mostly limited to organolead compounds. Like the lighter members of the group, le ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Black Sand
Black sand is sand that is black in color. One type of black sand is a heavy, glossy, partly magnetic mixture of usually fine sands containing minerals such as magnetite, found as part of a placer deposit. Another type of black sand, found on beaches near a volcano, consists of tiny fragments of basalt. While some beaches are predominantly made of black sand, even other color beaches (e.g. gold and white) can often have deposits of black sand, particularly after storms. Larger waves can sort out sand grains leaving deposits of heavy minerals visible on the surface of erosion escarpments. Placer deposits Black sands are used by miners and prospectors to indicate the presence of a placer formation. Placer mining activities produce a concentrate that is composed mostly of black sand. Black sand concentrates often contain additional valuables, other than precious metals: rare earth elements, thorium, titanium, tungsten, zirconium and others are often fractionated during igneous ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Assay
An assay is an investigative (analytic) procedure in laboratory medicine, mining, pharmacology, environmental biology and molecular biology for qualitatively assessing or quantitatively measuring the presence, amount, or functional activity of a target entity. The measured entity is often called the analyte, the measurand, or the target of the assay. The analyte can be a drug, biochemical substance, chemical element or compound, or cell in an organism or organic sample. An assay usually aims to measure an analyte's intensive property and express it in the relevant measurement unit (e.g. molarity, density, functional activity in enzyme international units, degree of effect in comparison to a standard, etc.). If the assay involves exogenous reactants (the reagents), then their quantities are kept fixed (or in excess) so that the quantity and quality of the target are the only limiting factors. The difference in the assay outcome is used to deduce the unknown quality or quantity o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hydraulic Mining
Hydraulic mining is a form of mining that uses high-pressure jets of water to dislodge rock material or move sediment.Paul W. Thrush, ''A Dictionary of Mining, Mineral, and Related Terms'', US Bureau of Mines, 1968, p.560. In the placer mining of gold or tin, the resulting water-sediment slurry is directed through sluice boxes to remove the gold. It is also used in mining kaolin and coal. Hydraulic mining developed from ancient Roman techniques that used water to excavate soft underground deposits. Its modern form, using pressurized water jets produced by a nozzle called a "monitor", came about in the 1850s during the California Gold Rush in the United States. Though successful in extracting gold-rich minerals, the widespread use of the process resulted in extensive environmental damage, such as increased flooding and erosion, and sediment blocking waterways and covering farm fields. These problems led to its legal regulation. Hydraulic mining has been used in various forms aroun ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sluicing
In syntax, sluicing is a type of ellipsis that occurs in both direct and indirect interrogative clauses. The ellipsis is introduced by a ''wh''-expression, whereby in most cases, everything except the ''wh''-expression is elided from the clause. Sluicing has been studied in detail in the early 21st century and it is therefore a relatively well-understood type of ellipsis. Sluicing occurs in many languages.See Merchant's (2001) extensive account of sluicing; it includes examples from numerous languages. Basic examples Sluicing is illustrated with the following examples. In each case, an embedded question is understood though only a question word or phrase is pronounced. (The intended interpretations of the question-denoting elliptical clause are given in parentheses; parts of these are anaphoric to the boldface material in the antecedent.) ::Phoebe ate something, but she doesn't know what. (=what she ate) ::Jon doesn't like the lentils, but he doesn't know why. (=why he doesn't li ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold Rush
A gold rush or gold fever is a discovery of gold—sometimes accompanied by other precious metals and rare-earth minerals—that brings an onrush of miners seeking their fortune. Major gold rushes took place in the 19th century in Australia, New Zealand, Brazil, Chile, South Africa, the United States, and Canada while smaller gold rushes took place elsewhere. In the 19th century, the wealth that resulted was distributed widely because of reduced migration costs and low barriers to entry. While gold mining itself proved unprofitable for most diggers and mine owners, some people made large fortunes, and merchants and transportation facilities made large profits. The resulting increase in the world's gold supply stimulated global trade and investment. Historians have written extensively about the mass migration, trade, colonization, and environmental history associated with gold rushes. Gold rushes were typically marked by a general buoyant feeling of a "free-for-all" in income mob ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
