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Gold-mining
Gold mining is the extraction of gold resources by mining. Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning. However, with the expansion of gold mining to ores that are not on the surface, has led to more complex extraction processes such as pit mining and gold cyanidation. In the 20th and 21st centuries, most volume of mining was done by large corporations, however the value of gold has led to millions of small, artisanal miners in many parts of the Global South. Like all mining, human rights and environmental issues are common issues in the gold mining industry. In smaller mines with less regulation, health and safety risks are much higher. History The exact date that humans first began to mine gold is unknown, but some of the oldest known gold artifacts were found in the Varna Necropolis in Bulgaria. The graves of the necropolis were built between 4700 and 4200 BC, indicating that gold mining could be at least 7000 ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Las Médulas
Las Médulas () is a historic gold-mining site near the town of Ponferrada in the comarca of El Bierzo (province of León, Castile and León, Spain). It was the most important gold mine, as well as the largest open-pit gold mine in the entire Roman Empire. Las Médulas Cultural Landscape is listed by UNESCO as a World Heritage Site. Advanced aerial surveys conducted in 2014 using LIDAR have confirmed the wide extent of the Roman-era works. The spectacular landscape of Las Médulas resulted from the '' ruina montium'' (wrecking of the mountains), a Roman mining technique described by Pliny the Elder in 77 AD. The technique employed was a type of hydraulic mining which involved undermining a mountain with large quantities of water. The water was supplied by interbasin transfer. At least seven long aqueducts tapped the streams of the La Cabrera district (where the rainfall in the mountains is relatively high) at a range of altitudes. The same aqueducts were used to wash t ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Gold
Gold is a chemical element with the symbol Au (from la, aurum) and atomic number 79. This makes it one of the higher atomic number elements that occur naturally. It is a bright, slightly orange-yellow, dense, soft, malleable, and ductile metal in a pure form. Chemically, gold is a transition metal and a group 11 element. It is one of the least reactive chemical elements and is solid under standard conditions. Gold often occurs in free elemental (native state), as nuggets or grains, in rocks, veins, and alluvial deposits. It occurs in a solid solution series with the native element silver (as electrum), naturally alloyed with other metals like copper and palladium, and mineral inclusions such as within pyrite. Less commonly, it occurs in minerals as gold compounds, often with tellurium ( gold tellurides). Gold is resistant to most acids, though it does dissolve in aqua regia (a mixture of nitric acid and hydrochloric acid), forming a soluble tetrachloroau ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dolaucothi
The Dolaucothi Gold Mines (; cy, Mwynfeydd Aur Dolaucothi) (), also known as the Ogofau Gold Mine, are ancient Roman surface and underground mines located in the valley of the River Cothi, near Pumsaint, Carmarthenshire, Wales. The gold mines are located within the Dolaucothi Estate which is now owned by the National Trust. They are the only mines for Welsh gold outside those of the Dolgellau gold-belt, and are a Scheduled Ancient Monument. They are also the only known Roman gold mines in Britain, although it does not exclude the likelihood that they exploited other known sources in Devon in South West England, north Wales, Scotland and elsewhere. The site is important for showing advanced Roman technology. Roman mining methods Archaeology suggests that gold extraction on this site may have started sometime in the Bronze Age, possibly by washing of the gold-bearing gravels of the river Cothi, the most elementary type of gold prospecting. Sextus Julius Frontinus wa ... [...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 arou ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ground Sluicing
Placer mining () is the mining of stream bed (alluvial) deposits for minerals. This may be done by open-pit (also called open-cast mining) or by various surface excavating equipment or tunneling equipment. Placer mining is frequently used for precious metal deposits (particularly gold) and gemstones, both of which are often found in alluvial deposits—deposits of sand and gravel in modern or ancient stream beds, or occasionally glacial deposits. The metal or gemstones, having been moved by stream flow from an original source such as a vein, are typically only a minuscule portion of the total deposit. Since gems and heavy metals like gold are considerably denser than sand, they tend to accumulate at the base of placer deposits. Placer deposits can be as young as a few years old, such as the Canadian Queen Charlotte beach gold placer deposits, or billions of years old like the Elliot Lake uranium paleoplacer within the Huronian Supergroup in Canada. The containing materia ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Hushing
Hushing is an ancient and historic mining method using a flood or torrent of water to reveal mineral veins. The method was applied in several ways, both in prospecting for ores, and for their exploitation. Mineral veins are often hidden below soil and sub-soil, which must be stripped away to discover the ore veins. A flood of water is very effective in moving soil as well as working the ore deposits when combined with other methods such as fire-setting. Hushing was used during the formation and expansion of the Roman Empire from the 1st century BC on to the end of the empire. It was also widely used later, and apparently survived until modern times where the cost of explosives was prohibitive. It was widely used in the United States, where it was known as "booming". A variant known as hydraulic mining where jets or streams of water are used to break down deposits, especially of alluvial gold and alluvial tin, is commonly used. History The method is well described by Pliny ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Kalgoorlie The Big Pit DSC04498
Kalgoorlie is a city in the Goldfields–Esperance region of Western Australia, located east-northeast of Perth at the end of the Great Eastern Highway. It is sometimes referred to as Kalgoorlie–Boulder, as the surrounding urban area includes the historic townsite of Boulder and the local government area is the City of Kalgoorlie–Boulder. Kalgoorlie-Boulder lies on the traditional lands of the Wangkatja group of peoples.The name "Kalgoorlie" is derived from the Wangai word ''Karlkurla'' or ''Kulgooluh'', meaning "place of the silky pears". The city was established in 1893 during the Western Australian gold rushes. It soon replaced Coolgardie as the largest settlement on the Eastern Goldfields. Kalgoorlie is the ultimate destination of the Goldfields Water Supply Scheme and the Golden Pipeline Heritage Trail. The nearby Super Pit gold mine was Australia's largest open-cut gold mine for many years. At August 2021, Kalgoorlie–Boulder had an estimated urban popula ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Bronze Age
The Bronze Age is a historic period, lasting approximately from 3300 BC to 1200 BC, characterized by the use of bronze, the presence of writing in some areas, and other early features of urban civilization. The Bronze Age is the second principal period of the three-age system proposed in 1836 by Christian Jürgensen Thomsen for classifying and studying ancient societies and history. An ancient civilization is deemed to be part of the Bronze Age because it either produced bronze by smelting its own copper and alloying it with tin, arsenic, or other metals, or traded other items for bronze from production areas elsewhere. Bronze is harder and more durable than the other metals available at the time, allowing Bronze Age civilizations to gain a technological advantage. While terrestrial iron is naturally abundant, the higher temperature required for smelting, , in addition to the greater difficulty of working with the metal, placed it out of reach of common use until th ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Trajan's Column
Trajan's Column ( it, Colonna Traiana, la, Columna Traiani) is a Roman triumphal column in Rome, Italy, that commemorates Roman emperor Trajan's victory in the Trajan's Dacian Wars, Dacian Wars. It was probably constructed under the supervision of the architect Apollodorus of Damascus at the order of the Roman Senate. It is located in Trajan's Forum, north of the Roman Forum. Completed in Anno Domini, AD 113, the freestanding column is most famous for its spiral bas relief, which depicts the Trajan's Dacian Wars, wars between the Romans and Dacians (101–102 and 105–106). Its design has inspired numerous victory columns, both ancient and modern. The structure is about in height, including its large pedestal. The shaft is made from a series of 20 colossal Carrara marble Drum (architecture), drums, each weighing about 32 tons, with a diameter of . The frieze winds around the shaft 23 times. Inside the shaft, a spiral staircase of 185 steps provides access to a viewing deck at ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Romania
Romania ( ; ro, România ) is a country located at the crossroads of Central, Eastern, and Southeastern Europe. It borders Bulgaria to the south, Ukraine to the north, Hungary to the west, Serbia to the southwest, Moldova to the east, and the Black Sea to the southeast. It has a predominantly temperate- continental climate, and an area of , with a population of around 19 million. Romania is the twelfth-largest country in Europe and the sixth-most populous member state of the European Union. Its capital and largest city is Bucharest, followed by Iași, Cluj-Napoca, Timișoara, Constanța, Craiova, Brașov, and Galați. The Danube, Europe's second-longest river, rises in Germany's Black Forest and flows in a southeasterly direction for , before emptying into Romania's Danube Delta. The Carpathian Mountains, which cross Romania from the north to the southwest, include Moldoveanu Peak, at an altitude of . Settlement in what is now Romania began in the Lower Pale ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Transylvania
Transylvania ( ro, Ardeal or ; hu, Erdély; german: Siebenbürgen) is a historical and cultural region in Central Europe, encompassing central Romania. To the east and south its natural border is the Carpathian Mountains, and to the west the Apuseni Mountains. Broader definitions of Transylvania also include the western and northwestern Romanian regions of Crișana and Maramureș, and occasionally Banat. Transylvania is known for the scenery of its Carpathian landscape and its rich history. It also contains Romania's second-largest city, Cluj-Napoca, and other iconic cities and towns such as Brașov, Sibiu, Târgu Mureș, Alba Iulia and Sighișoara. It is also the home of some of Romania's UNESCO World Heritage Sites such as the Villages with fortified churches, the Historic Centre of Sighișoara, the Dacian Fortresses of the Orăștie Mountains and the Roșia Montană Mining Cultural Landscape. It was under the rule of the Agathyrsi, part of the Dacian Kingd ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Dacia
Dacia (, ; ) was the land inhabited by the Dacians, its core in Transylvania, stretching to the Danube in the south, the Black Sea in the east, and the Tisza in the west. The Carpathian Mountains were located in the middle of Dacia. It thus roughly corresponds to the present-day countries of Romania, as well as parts of Moldova, Bulgaria, Serbia, Hungary, Slovakia, and Ukraine. A Dacian Kingdom of variable size existed between 82 BC until the Roman conquest in AD 106, reaching its height under King Burebista. As a result of the two wars with Emperor Trajan, the population was dispersed and the central city, Sarmizegetusa Regia, was destroyed by the Romans, but was rebuilt by the latter to serve as the capital of the Roman province of Dacia. The Free Dacians, living the territory of modern-day Northern Romania disappeared with the start of the Migration Period. Nomenclature The Dacians are first mentioned in the writings of the Ancient Greeks, in Herodotus (''Histo ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
