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Gold Nugget
:''"Gold nugget" may also refer to the catfish Baryancistrus xanthellus or the mango cultivar Gold Nugget.'' A gold nugget is a naturally occurring piece of native gold. Watercourses often concentrate nuggets and finer gold in placers. Nuggets are recovered by placer mining, but they are also found in residual deposits where the gold-bearing veins or lodes are weathered. Nuggets are also found in the tailings piles of previous mining operations, especially those left by gold mining dredges. Formation Nuggets are gold fragments weathered out of an original lode. They often show signs of abrasive polishing by stream action, and sometimes still contain inclusions of quartz or other lode matrix material. A 2007 study on Australian nuggets ruled out speculative theories of supergene formation via in-situ precipitation, cold welding of smaller particles, or bacterial concentration, since crystal structures of all of the nuggets examined proved they were originally formed at high tem ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Lead
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 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metal Detector
A metal detector is an instrument that detects the nearby presence of metal. Metal detectors are useful for finding metal objects on the surface, underground, and under water. The unit itself, consist of a control box, and an adjustable shaft, which holds a pickup coil, which can vary in shape and size. If the pickup coil comes near a piece of metal, the control box will register its presence by a changing tone, a flashing light, and or by a needle moving on an indicator. Usually the device gives some indication of distance; the closer the metal is, the higher the tone in the earphone or the higher the needle goes. Another common type are stationary "walk through" metal detectors used at access points in prisons, courthouses, airports and psychiatric hospitals to detect concealed metal weapons on a person's body. The simplest form of a metal detector consists of an oscillator producing an alternating current that passes through a coil producing an alternating magnetic field. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Canaã
Canaã (Portuguese for "Canaan") is a municipality ''(município)'' in the state of Minas Gerais in Brazil. The population is 4,548 (2020 est.) in an area of 175 km². See also * List of municipalities in Minas Gerais This is a list of the municipalities in the state of Minas Gerais (MG), located in the Southeast Region of Brazil. Minas Gerais is divided into 853 municipalities, which are grouped into 66 microregions, which are grouped into 12 mesoregions. ... References Municipalities in Minas Gerais {{MinasGerais-geo-stub ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Serra Pelada
Serra Pelada (English: "Naked Mountain") is a Brazilian village, district of the municipality of Curionópolis, in the southeast of Pará. Serra Pelada was a large gold mine in Brazil south of the mouth of the Amazon River. The mine was made infamous by the still images taken by Alfredo Jaar and later by Sebastião Salgado and the first section of Godfrey Reggio's 1988 documentary ''Powaqqatsi'', showing an anthill of workers moving vast amounts of ore by hand. Because of the chaotic nature of the operation estimating the number of miners was difficult, but at least 100,000 people were thought to be present, making it one of the largest mines in the world. Today the Serra Pelada mine is abandoned and the giant open pit that was created by hand has filled with water, creating a small polluted lake. Discovery In January 1979, farmer Genésio Ferreira da Silva hired a geologist to investigate whether gold he found on his property was part of a larger deposit. A local child swimming ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welcome Nugget
The Welcome Nugget is a large gold nugget, weighing 2,217 troy ounces 16 pennyweight. (68.98 kg), that was discovered by a group of twenty-two Cornish miners at the Red Hill Mining Company site at Bakery Hill (near the present intersection of Mair and Humffray Street) in Ballarat, Victoria, Australia, on 9 June 1858. It was located in the roof of a tunnel 55 metres (180 feet) underground. Shaped roughly like a horse's head, it measured around 49 cm (18 in) long by 15 cm (6 in) wide and 15 cm (6 in) high, and had a roughly indented surface. It was assayed by William Birkmyre of the Port Phillip Gold Company and given its name by finder Richard Jeffery. Eclipsed by the discovery of the larger Welcome Stranger eleven years later in 1869 (also in Victoria), it remains the second largest gold nugget ever found. The finders had been among the first to introduce steam-driven machinery into the field at Ballarat and had looked first at nearby Cr ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Moliagul, Victoria
Moliagul is a small township in Victoria, Australia, northwest of Melbourne and west of Bendigo. The town's name is believed to be a derivation of the aboriginal word "moliagulk", meaning "wooded hill". The area is notable for the discovery of a number of gold nuggets. These finds include the world's largest, the Welcome Stranger, which was discovered in 1869 by John Deason and Richard Oates. From what was once a thriving goldfields town, Moliagul today is a virtual ghost town and consists of a number of scattered houses. In 1855 it is estimated there were 16,000 people living in the immediate area during the peak of the Victorian gold rush period. Moliagul Post Office opened on 15 November 1858 and closed in 1971. The town is composed of scattered rural dwellings and small farms, a hotel (now closed), museum, the old school (now a hall) and former church. There are a number of historical sites including a stone monument to the Reverend John Flynn, founder of the Royal Flying ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Welcome Stranger
The Welcome Stranger is the biggest alluvial gold nugget that has ever been found, which had a calculated refined weight of .Potter, Terry F. (1999) ''The Welcome Stranger: a definitive account of the worlds largest alluvial gold nugget''. It measured and was discovered by prospectors John Deason and Richard Oates on 5 February 1869 at Moliagul, Victoria, Australia, about 14.6 kilometres (9 miles) north-west of Dunolly. Discovery Found only below the surface, near the base of a tree on a slope leading to what was then known as Bulldog Gully, the nugget had a gross weight of (241 lb 10 oz). Its trimmed weight was (210 lbs), and its net weight was (192 lbs 11.5 oz). At the time of the discovery, there were no scales capable of weighing a nugget this large, so it was broken into three pieces on an anvil by Dunolly-based blacksmith Archibald Walls. Deason, Oates, and a few friends took the nugget to the London Chartered Bank of Australia, in Dunolly, which advanced them ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Electrum
Electrum is a naturally occurring alloy of gold and silver, with trace amounts of copper and other metals. Its color ranges from pale to bright yellow, depending on the proportions of gold and silver. It has been produced artificially, and is also known as "green gold".Emsley, John (2003Nature's building blocks: an A–Z guide to the elements Oxford University Press. . p. 168 Electrum was used as early as the third millennium BC in Old Kingdom of Egypt, sometimes as an exterior coating to the pyramidions atop ancient Egyptian pyramids and obelisks. It was also used in the making of ancient drinking vessels. The first known metal coins made were of electrum, dating back to the end of the 7th century or the beginning of the 6th century BC. For several decades, the medals awarded with the Nobel Prize have been made of gold-plated green gold. Etymology The name "electrum" is the Latinized form of the Greek word ἤλεκτρον (''ḗlektron''), mentioned in the ''Odyssey' ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkish-orange color. Copper is used as a conductor of heat and electricity, as a building material, and as a constituent of various metal alloys, such as sterling silver used in jewelry, cupronickel used to make marine hardware and coins, and constantan used in strain gauges and thermocouples for temperature measurement. Copper is one of the few metals that can occur in nature in a directly usable metallic form ( native metals). This led to very early human use in several regions, from circa 8000 BC. Thousands of years later, it was the first metal to be smelted from sulfide ores, circa 5000 BC; the first metal to be cast into a shape in a mold, c. 4000 BC; and the first metal to be purposely alloyed with another metal, tin, to create ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Silver
Silver is a chemical element with the Symbol (chemistry), symbol Ag (from the Latin ', derived from the Proto-Indo-European wikt:Reconstruction:Proto-Indo-European/h₂erǵ-, ''h₂erǵ'': "shiny" or "white") and atomic number 47. A soft, white, lustrous transition metal, it exhibits the highest electrical conductivity, thermal conductivity, and reflectivity of any metal. The metal is found in the Earth's crust in the pure, free elemental form ("native silver"), as an alloy with gold and other metals, and in minerals such as argentite and chlorargyrite. Most silver is produced as a byproduct of copper, gold, lead, and zinc Refining (metallurgy), refining. Silver has long been valued as a precious metal. Silver metal is used in many bullion coins, sometimes bimetallism, alongside gold: while it is more abundant than gold, it is much less abundant as a native metal. Its purity is typically measured on a per-mille basis; a 94%-pure alloy is described as "0.940 fine". As one of th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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