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Treadwell Mine
The Treadwell gold mine was on the south side of Douglas Island, east of downtown Douglas and southeast of downtown Juneau, owned and operated by John Treadwell. Composed of four sub-sites, Treadwell was in its time the largest hard rock gold mine in the world, employing over 2,000 people."TREADWELL GOLD MINE". Accessed May 17, 2008. Between 1881 and 1922, over 3 million s of gold were extracted. Not much remains today except for a few crumbling buildings and a "". Although John Treadwell had twelve years of experience in both placer and lode mines, he was a carpent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treadwell Mine
The Treadwell gold mine was on the south side of Douglas Island, east of downtown Douglas and southeast of downtown Juneau, owned and operated by John Treadwell. Composed of four sub-sites, Treadwell was in its time the largest hard rock gold mine in the world, employing over 2,000 people."TREADWELL GOLD MINE". Accessed May 17, 2008. Between 1881 and 1922, over 3 million s of gold were extracted. Not much remains today except for a few crumbling buildings and a "". Although John Treadwell had twelve years of experience in both placer and lode mines, he was a carpent ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Stephens Passage
Stephens Passage is a channel in the Alexander Archipelago in the southeastern region of the U.S. state of Alaska. It runs between Admiralty Island to the west and the Alaska mainland and Douglas Island to the east, and is about 170 km (105 mi) long. Juneau, the capital of Alaska, is near the north end, on Gastineau Channel. Stephens Passage was named in 1794 by George Vancouver, probably for Sir Philip Stephens. It was first charted the same year by Joseph Whidbey, master of HMS ''Discovery'' during Vancouver's 1791-95 expedition. The passage was surveyed by the US Coast & Geodetic Survey (USCGS) ship ''Explorer'' and two smaller vessels in 1920. References External links *Panorama A panorama (formed from Greek πᾶν "all" + ὅραμα "view") is any wide-angle view or representation of a physical space, whether in painting, drawing, photography, film, seismic images, or 3D modeling. The word was originally coined in ... of the passage and Admiralty Is ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Smelting
Smelting is a process of applying heat to ore, to extract a base metal. It is a form of extractive metallurgy. It is used to extract many metals from their ores, including silver, iron, copper, and other base metals. Smelting uses heat and a chemical reducing agent to decompose the ore, driving off other elements as gases or slag and leaving the metal base behind. The reducing agent is commonly a fossil fuel source of carbon, such as coke—or, in earlier times, charcoal. The oxygen in the ore binds to carbon at high temperatures due to the lower potential energy of the bonds in carbon dioxide (). Smelting most prominently takes place in a blast furnace to produce pig iron, which is converted into steel. The carbon source acts as a chemical reactant to remove oxygen from the ore, yielding the purified metal element as a product. The carbon source is oxidized in two stages. First, the carbon (C) combusts with oxygen (O2) in the air to produce carbon monoxide (CO). Second, the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Halogenation
In chemistry, halogenation is a chemical reaction that entails the introduction of one or more halogens into a compound. Halide-containing compounds are pervasive, making this type of transformation important, e.g. in the production of polymers, drugs. This kind of conversion is in fact so common that a comprehensive overview is challenging. This article mainly deals with halogenation using elemental halogens (F2, Cl2, Br2, I2). Halides are also commonly introduced using salts of the halides and halogen acids. Many specialized reagents exist for and introducing halogens into diverse substrates, e.g. thionyl chloride. Organic chemistry Several pathways exist for the halogenation of organic compounds, including free radical halogenation, ketone halogenation, electrophilic halogenation, and halogen addition reaction. The nature of the substrate determines the pathway. The facility of halogenation is influenced by the halogen. Fluorine and chlorine are more electrophilic and are m ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Independence Day (United States)
Independence Day (colloquially the Fourth of July) is a federal holiday in the United States commemorating the Declaration of Independence, which was ratified by the Second Continental Congress on July 4, 1776, establishing the United States of America. The Founding Father delegates of the Second Continental Congress declared that the Thirteen Colonies were no longer subject (and subordinate) to the monarch of Britain, King George III, and were now united, free, and independent states. The Congress voted to approve independence by passing the Lee Resolution on July 2 and adopted the Declaration of Independence two days later, on July 4. Independence Day is commonly associated with fireworks, parades, barbecues, carnivals, fairs, picnics, concerts, baseball games, family reunions, political speeches, and ceremonies, in addition to various other public and private events celebrating the history, government, and traditions of the United States. Independence Day is the n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Christmas
Christmas is an annual festival commemorating Nativity of Jesus, the birth of Jesus, Jesus Christ, observed primarily on December 25 as a religious and cultural celebration among billions of people Observance of Christmas by country, around the world. A Calendar of saints, feast central to the Christian liturgical year, it is preceded by the season of Advent or the Nativity Fast and initiates the season of Christmastide, which historically in the West lasts Twelve Days of Christmas, twelve days and culminates on Twelfth Night (holiday), Twelfth Night. Christmas Day is a public holiday in List of holidays by country, many countries, is celebrated religiously by a majority of Christians, as well as Christian culture, culturally by many non-Christians, and forms an integral part of the Christmas and holiday season, holiday season organized around it. The traditional Christmas narrative recounted in the New Testament, known as the Nativity of Jesus, says that Jesus was born in Bet ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Machine Press
A forming press, commonly shortened to press, is a machine tool that changes the shape of a work-piece by the application of pressure. The operator of a forming press is known as a press-tool setter, often shortened to tool-setter. Presses can be classified according to * their mechanism: hydraulic, mechanical, pneumatic; * their function: forging presses, stamping presses, press brakes, punch press, etc. * their structure, e.g. Knuckle-joint press, screw press * their controllability: conventional vs. servo-presses Shop Press Typically consisting of a simple rectangular frame, often fabricated from C-channel or tubing, containing a bottle jack or hydraulic cylinder to apply pressure via a ram to a work-piece. Often used for general-purpose forming work in the auto mechanic shop, machine shop, garage or basement shops, etc. Typical shop presses are capable of applying between 1 and 30 tons pressure, depending on size and construction. Lighter-duty versions are often c ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Treadwell Miners , a variant spelling of this name
{{disambiguation, geo ...
Treadwell may refer to: * Treadwell (name), includes a list of people with the name * Treadwell (Droid), fictional character in Star Wars * Treadwell gold mine, southeast of Juneau, Alaska * Treadwell, Georgia, an unincorporated community * Treadwell, New York, hamlet located within the town of Franklin in Delaware County * Treadwell, Ontario * Mount Treadwell, Marie Byrd Land, Antarctica * Treadwell & Martin, former London architect firm * Treadwell's Bookshop, a London bookshop specialising in esoteric and occult works. See also *Tredwell Tredwell is an English surname. It was the 13,038th most common surname in the United Kingdom in 1998. Notable people with the name include : * James Tredwell (born 1982), English cricketer * Roger Tredwell (1885–1961), American diplomat * Thom ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Geologic Map
A geologic map or geological map is a special-purpose map made to show various geological features. Rock units or geologic strata are shown by color or symbols. Bedding planes and structural features such as faults, folds, are shown with strike and dip or trend and plunge symbols which give three-dimensional orientations features. Stratigraphic contour lines may be used to illustrate the surface of a selected stratum illustrating the subsurface topographic trends of the strata. Isopach maps detail the variations in thickness of stratigraphic units. It is not always possible to properly show this when the strata are extremely fractured, mixed, in some discontinuities, or where they are otherwise disturbed. Symbols Lithologies Rock units are typically represented by colors. Instead of (or in addition to) colors, certain symbols can be used. Different geologic mapping agencies and authorities have different standards for the colors and symbols to be used for rocks of differ ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Pyrite
The mineral pyrite (), or iron pyrite, also known as fool's gold, is an iron sulfide with the chemical formula Iron, FeSulfur, S2 (iron (II) disulfide). Pyrite is the most abundant sulfide mineral. Pyrite's metallic Luster (mineralogy), luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of ''fool's gold''. The color has also led to the nicknames ''brass'', ''brazzle'', and ''Brazil'', primarily used to refer to pyrite found in coal. The name ''pyrite'' is derived from the Greek language, Greek (), 'stone or mineral which strikes fire', in turn from (), 'fire'. In ancient Roman times, this name was applied to several types of stone that would create sparks when struck against steel; Pliny the Elder described one of them as being brassy, almost certainly a reference to what we now call pyrite. By Georgius Agricola's time, , the term had become a generic term for all of the pyrite group, sulfide minerals. Pyrite is usua ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sulfide Minerals
The sulfide minerals are a class of minerals containing sulfide (S2−) or disulfide (S22−) as the major anion. Some sulfide minerals are economically important as metal ores. The sulfide class also includes the selenides, the tellurides, the arsenides, the antimonides, the bismuthinides, the sulfarsenides and the sulfosalts.http://www.minerals.net/mineral/sort-met.hod/group/sulfgrp.htm Minerals.net Dana Classification, SulfidesKlein, Cornelis and Cornelius S. Hurlbut, Jr., 1986, ''Manual of Mineralogy'', Wiley, 20th ed., pp 269-293 Sulfide minerals are inorganic compounds. Minerals Common or important examples include: * Acanthite *Chalcocite *Bornite *Galena *Sphalerite *Chalcopyrite *Pyrrhotite *Millerite *Pentlandite *Covellite *Cinnabar *Realgar *Orpiment *Stibnite *Pyrite *Marcasite *Molybdenite Sulfarsenides: *Cobaltite *Arsenopyrite *Gersdorffite Sulfosalts: *Pyrargyrite *Proustite *Tetrahedrite *Tennantite *Enargite *Bournonite *Jame ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dike (geology)
A dike or dyke, in Geology, geological usage, is a sheet of rock that is formed in a Fracture (geology), fracture of a pre-existing rock body. Dikes can be either Intrusive rock, magmatic or Sedimentary rock, sedimentary in origin. Magmatic dikes form when magma flows into a crack then solidifies as a sheet intrusion, either cutting across layers of rock or through a contiguous mass of rock. Clastic dikes are formed when sediment fills a pre-existing crack.Essentials of Geology, 3rd Ed, Stephen Marshak Magmatic dikes A magmatic dike is a sheet of igneous rock that cuts across older rock beds. It is formed when magma fills a fracture in the older beds and then cools and solidifies. The dike rock is usually more resistant to weathering than the surrounding rock, so that erosion exposes the dike as a natural wall or ridge. It is from these natural walls that dikes get their name. Dikes preserve a record of the fissures through which most mafic magma (fluid magma low in silica) reac ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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