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71-501: The Summitville mine was the scene of a major environmental disaster in the 1990s when the liner of a cyanide -laced tailing pond began leaking heavily. Summitville is in the Summitville caldera , one of many extinct volcanoes making up the San Juan volcanic field . One, La Garita Caldera , is 35 miles (56 km) in diameter. Large beds of lava , some extending under the floor of

142-598: A British Columbia court, the US Government declared the site a superfund cleanup site and spent $ 155,000,000 of public funds cleaning up the site. In 1991 SCMCI was served with a cease-and-desist order by the state government, concerned with metal levels in nearby water due to the run-off of excess water from the heap leach pad and through the damaged pad liner. Possibly 85,000 US gallons (320 m ) of contaminated water had leaked into nearby creeks. In December 1992 Galactic Resources Ltd. declared itself bankrupt and declared that

213-698: A combination of factors including the depletion of easily accessible gold deposits, harsh weather conditions, and the political instability at the time. The Welsh gold rush occurred in Wales , more so in the Dolgellau area of Gwynedd , during the 19th century. Gold deposits were discovered in Welsh mountains, with reports of gold being found in rivers Mawddach and Tryweryn . By the mid-19th century, commercial mining operations had begun. Wales' gold gained popularity for its quality and rarity, leading to its use in royal jewelry for

284-716: A critical source of income and livelihood, providing employment opportunities and economic support in regions with limited alternative options. Artisanal mining operations vary in scale, from individuals panning for gold in rivers and streams, to small groups working collectibely in informal mining camps, often referred to as ' galamsey ' in West Africa . Gold mining can create employment opportunities in mining operations and related sectors. Howevers, these jobs may be temporary. The sector's reliance on fluctuating global gold prices can lead to economic stability for communities dependent on mining. The discovery of significant gold deposits in

355-437: A gravel screening plant and sluice box floating in a temporary pond. The pond is excavated in the gravel bar and filled from the natural water table. "Pay" gravel is excavated from the front face of the pond and processed through the floating plant, with the gold trapped in the onboard sluice box and tailings stacked behind the plant, steadily filling in the back of the pond as the operation moves forward. This type of gold mining

426-467: A large scale to extract gold from extensive alluvial (loose sediment) deposits, such as those at Las Medulas . Mining was under the control of the state but the mines may have been leased to civilian contractors some time later. The gold served as the primary medium of exchange within the empire, and was an important motive in the Roman conquest of Britain by Claudius in the first century AD; although there

497-488: A lower grade. Tailings can contain lead, mercury, cadmium, and arsenic. These toxins can pose health risks for local communities. Arsenic is typically found in gold-containing ores, and gold processing may contaminate groundwater or the atmosphere. This pollution may persist for decades. Furthermore, mining operations use large quantities of water for processing ore and can result in the contamination of water sources with heavy metals, such as mercury and cyanide , used in

568-727: A tributary of the Klondike River by George Carmack and his Indigenous companions, Skookum Jim Mason and Tagish Charlie . As prospectors arrived in Klondike, makeshift towns and settlements sprang up along the rivers, including Dawson City , which because the largest town in Yukon at the height of the gold rush. Prospectors employed various mining techniques to extract gold from the Klondike's streams and riverbeds, including placer mining, dredging, and hydraulic mining. The Carlin Trend of Nevada, U.S.,

639-418: Is a cyanide extraction method, or gold cyanidation, introduced in the late 1800s. This a metallurgical technique used to extract gold from lower grade ores by converting gold into a water-soluble coordination complex. Finely ground rock is treated with a solution of sodium cyanide . The extract is absorbed onto carbon and then removed from the carbon with a solution of caustic soda and cyanide. Gold cyanide

710-429: Is a method of extracting gold from alluvial deposits such as sand, gravel, and sediment. These are known as placer deposits which are typically found in riverbeds, stream beds, and floodplains. These deposits typically contain minerals that are resistant to weathering and eroision like gold , platinum , diamonds , and more. They are characterized by their relatively high concentration of valuable minerals compared to

781-415: Is characterized by its low cost, as each rock is moved only once. It also has low environmental impact, as no stripping of vegetation or overburden is necessary, and all process water is fully recycled. Such operations are typical on New Zealand's South Island and in the Klondike region of Canada. Also called a cradle, a rocker box uses riffles located in a high-walled box to trap gold in a similar manner to

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852-616: Is done by small-scale miners using suction dredges. These are small machines that float on the water and are usually operated by one or two people. A suction dredge consists of a sluice box supported by pontoons, attached to a suction hose which is controlled by a miner working beneath the water. This method is particularly popular in areas where gold is found at river bottoms or submerge deposits . Suction dredging can have environmental impacts, moreso on aquatic habitats and water quality. Regulations and best practices are often in place to minimize these impacts. State dredging permits in many of

923-436: Is essentially a man made channel with riffles set in the bottom. The riffles are designed to create dead zones in the current to allow gold to drop out of suspension. The box is placed in the stream to channel water flow. Gold-bearing material is placed at the top of the box. The material is carried by the current through the volt where gold and other dense material settles out behind the riffles. Less dense material flows out of

994-841: Is estimated that the total gold production in Karnataka to date is 1000 tons. The mining of the Hungarian deposit (present-day Slovakia) primarily around Kremnica was the largest of the Medieval period in Europe. In South America, gold mining in the Andes dates back to thousands of years, with the Inca empire employing extensive gold mining operations in regions such as present-day Peru and Ecuador . They used stone tools and simple mining techniques to extract gold from rivers, streams, and surface deposits. During

1065-751: Is in the San Juans. The San Juan Mountains are also distinctive for their high altitude plateaus and peaks. As a result, facilities in the towns and cities of the region are among the highest in the nation. Telluride Airport , at an elevation of 9,070 feet, is the highest in the United States with regularly scheduled commercial service. Human history at the eastern edge of the San Juan Mountains dates back thousands of years. Smithsonian archaeologists have identified paleo-Indian sites that are about 5,000 years old, located near Great Sand Dunes National Park and at

1136-677: Is only one known Roman gold mine at Dolaucothi in west Wales. Gold was a prime motivation for the campaign in Dacia when the Romans invaded Transylvania in what is now modern Romania in the second century AD. The legions were led by the emperor Trajan, and their exploits are shown on Trajan's Column in Rome and the several reproductions of the column elsewhere (such as the Victoria and Albert Museum in London ). Under

1207-465: Is popular, as is wilderness trekking and mountain climbing . Many of the old mining camps are popular sites of summer homes . Though the San Juans are extremely steep and receive much snow, so far only Telluride has made the transition to a major ski resort . Purgatory Resort , once known as Durango Mountain Resort, is a small ski area 26 miles north of Durango. There is also skiing on Wolf Creek Pass at

1278-962: Is produced by major corporations, there are an estimated 10 to 15 million small-scale artisanal gold miners worldwide. Around 4.5 million of them are women, and an estimated 600,000 children work in illegal artisanal gold mines. Artisanal miners use rudimentary methods to extract and process gold. Many of these people are mining to escape extreme poverty , unemployment and landlessness . In Ghana, galamsey miners are estimated to number 20,000 to 50,000. In neighboring francophone countries, such workers are called orpailleurs . In Brazil, Venezuela, Suriname, and French Guiana, workers are called garimpeiros . These workers are not required to claim responsibility for their social and environmental impacts. Miners risk government persecution, mine shaft collapses, and toxic poisoning from unsafe chemicals used in processing, such as mercury. For example, in Ghana during 2009,

1349-628: Is then converted to relatively pure gold through gold parting . There are many environmental hazards associated with this extraction method, largely due to the high toxicity of the cyanide compounds. Furthermore, there are potentials for accidental spills or leaks to cause harm to aquatic ecosystems and human health. For example, in 2000, the Baia Mare cyanide spill in northern Romania released approximately 100,000 cubic metres (3,500,000 cu ft) of waste water contaminated with heavy metal sludge and up to 120 long tons (122 t) of cyanide into

1420-519: 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 6,724 years old. During a series of excavations carried out between 1878 and 1992, several graves were found with more than 6kg of gold. A group of German and Georgian archaeologists claims

1491-402: Is used for crop irrigation. A United States Geological Survey investigation arrived at three major conclusions: Extreme acid-rock drainage is the dominant long-term environmental concern at the Summitville mine and could have been predicted given the geological characteristics of the deposit. Extensive remedial efforts are required to isolate both unweathered sulfides and soluble metal salts in

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1562-719: The Alamosa River in 1990. Although cyanide from the heap leach pads also leaked in the watershed, cyanide is believed to have quickly volatilized into the atmosphere without damaging downstream aquatic life. Rocks in the Summitville area were millions of years ago subjected to acid-sulfate alteration, which causes the streams that drain the area to be naturally acidic and naturally high in metals. The very names of nearby creeks are evidence of poor natural water quality: Iron Creek, Alum Creek, and Bitter Creek. Mining at Summitville, by exposing more rock surface to weathering, increased acidity and concentrations of dissolved metals in runoff from

1633-615: The British royal family . During the 19th century, numerous gold rushes in remote regions around the globe caused large migrations of miners, such as the California Gold Rush of 1849. This is one of the most famous gold rushes in history. The discovery of gold at Sutter's Mill in California sparked a massive migration of people from around the world to California in search of gold. The rush significantly accelerated westward expansion in

1704-690: The Bronze Age , sites in the Eastern Desert became a great source of gold-mining for nomadic Nubians, who used "two-hand-mallets" and "grinding ore extraction ." By the Old Kingdom , the oval mallet was introduced for mining. By the Middle Kingdom , stone mortars to process ores and a new gold-washing technique were introduced. During the New Kingdom , Nubian mining expanded under Egyptian occupation with

1775-568: The Dompoase mine collapse killed 18 workers. It was the worst mining disaster in Ghanaian history. Children in these mines suffer extremely harsh working conditions and various hazards such as collapsing tunnels, explosions, and chemical exposure. Children may be especially vulnerable to these hazards and many suffer from serious respiratory conditions, hearing, and vision problems. Gold mining by large multi-national corporations produces about 80% of

1846-664: The Kolar gold fields was mined to a depth of 50 metres (160 ft) during the Gupta period in the fifth century AD. During the Chola period in the 9th and 10th century AD, the scale of the operation grew. The metal continued to be mined by the eleventh century kings of South India, the Vijayanagara Empire from 1336 to 1560, and later by Tipu Sultan , the king of Mysore state and the British. It

1917-457: The Sakdrisi site in southern Georgia , dating to the 3rd or 4th millennium BC, may be the world's oldest known gold mine. Gold has been prized by humans since prehistoric times. Archaeological evidence suggests that humans were mining gold as far back as 4000 BCE, with some the earliest known gold artifacts dating back to ancient Mesopotamia . Particularly in the region of present-day Iraq, gold

1988-458: The San Luis Valley , are characteristic of the eastern slope of the San Juans. Tourism is a major part of the regional economy, with the narrow gauge railway between Durango and Silverton being an attraction mostly in the summer and fall. Off-roading is popular on the old trails which linked the historic mining camps, including the notorious Black Bear Road . Visiting old ghost towns

2059-546: The Southern Ute Indian Reservation received $ 25,000 per year. Gold veins were found at 11,500 feet on South Mountain in 1873 and the town was founded when stamp and amalgamation mills were built. By 1885 there were more than 250 individual claims in operation. The site was soon mined out, with the weather of the 3,500 m high site adding to difficulties. The site was re-opened on a number of occasions for gold or other metals but with little success, and prior to

2130-511: The Tisza River. Historically, mercury was used extensively in placer gold mining in order to form mercury-gold amalgam with smaller gold particles, and thereby increase the gold recovery rates. First, the gold ore is crushed and ground to a fine powder to expose the gold particles for amalgamation. Then, this finely ground ore is mixed with liquid mercury to amalgamate it. Mercury forms an amalgam, an alloy, with gold particles to allow for

2201-595: The United States , located in Rio Grande County, Colorado 25 miles (40 km) south of Del Norte . It is remembered for the environmental damage caused in the 1980s by the leakage of mining by-products into local waterways and then the Alamosa River . Charles Baker's group of prospectors found traces of placer gold in the San Juan Mountains in 1860 at Eureka, Colorado . The group was forced out in 1861 by

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2272-502: The Wolf Creek ski area . Recently Silverton Mountain ski area has begun operation near Silverton. The range is also a popular destination for endurance sports like trail running and mountain biking; Silverton is home to the Hardrock 100 Endurance Run one of the most difficult and technical ultra-marathons in the world. The Rio Grande drains the east side of the range. The other side of

2343-570: The Amazon rainforest, Indigenous peoples have been killed and had their rightfully owned land stolen from them. As a consequence of this, some have left the rainforest to move to cities which further puts them at risk to disease, homelessness, and poverty. Artisanal gold mining is widespread across Africa , occurring in numerous countries including Ghana , Mali , Burkina Faso , Tanzania , Zimbabwe , and many others. For many individuals and communities in rural Africa, artisanal gold mining represents

2414-875: The Eastern Roman Empire Emperor Justinian's rule, gold was mined in the Balkans, Anatolia, Armenia, Egypt, and Nubia. In the area of the Kolar Gold Fields in Bangarpet Taluk , Kolar district of Karnataka state, India; gold was first mined prior to the 2nd and 3rd century AD by digging small pits. Golden objects found in Harappa and Mohenjo-daro have been traced to Kolar through the analysis of impurities – the impurities include 11% silver concentration, found only in KGF ore. The Champion reef at

2485-464: The Highlands during the 16th and 17th century. Gold deposits were discovered in rivers and streams, leading to a surge in prospecting and mining activity. The Scottish Crown took an interest in gold discoveries, in hopes of aiding the kingdom's economy and revenue. King James IV of Scotland established a royal mint to produce gold coins from Scottish gold. The Scottish gold rush eventually waned due to

2556-932: The Middle Ages, Europe experience several gold rushes. Most notably in regions like Transylvania, Scotland, and Wales. These rushes were often small-scale and localised compared to later rushes in history. The Transylvania gold rush took place in the Kingdom of Hungary (present-day Romania ), primarily in the region of Transylvania during the medieval period. Transylvania was known for its rich mineral resources including gold, silver, and other metals. Miners in Transylvania used both surface and underground mining techniques to extract gold from alluvial deposits and veins. These methods include panning, sluicing, and rudimentary shaft mining. The Scottish gold rush occurred in Scotland, primarily in

2627-556: The San Juans, the western slope of the continental divide , is drained by tributaries of the San Juan , Dolores and Gunnison rivers, which all flow into the Colorado River . The San Juan and Uncompahgre National Forests cover a large portion of the San Juan Mountains. The Continental Divide Trail , a long-distance hiking trail follows the crest of the San Juan Mountains. The Weminuche Wilderness , Colorado's largest wilderness area, with an area of 499,771 acres (202,250 ha)

2698-551: The Summitville site. Results of studies as of late 1993 indicate that mining at Summitville has had no discernible short-term adverse effects on barley or alfalfa crops irrigated with Alamosa River water. Remediation of the site will help to ensure that no adverse effects occur over the longer term. Gold mining Gold mining is the extraction of gold by mining . Historically, mining gold from alluvial deposits used manual separation processes, such as gold panning . The expansion of gold mining to ores that are not on

2769-523: The United States and had profound effects on the region's economy and society. The gold rushes began in 1851 when Edward Hargraves , a prospector, discovered gold near Bathhurst , New South Wales . The most well known gold rush in Australia was the Victorian Gold Rush . Thousands of people, known as 'diggers', came from around the world to Australia in search of gold, which ultimately contributed to

2840-484: The United States gold dredging areas specify a seasonal time period and area closures to avoid conflicts between dredgers and the spawning time of fish populations. Some US states, such as Montana, require an extensive permitting procedure, including permits. Some large suction dredges [100 horsepower (75 kW) & 250 mm (10 in)] are used in commercial production throughout the world. Small suction dredges are much more efficient at extracting smaller gold than

2911-642: The Ute Tribe, who had been awarded the area in a US treaty. Gold was discovered in Wightman Fork, on South Mountain, which is the same location of present-day Summitville. More prospectors returned in 1871, when lode gold was found in the Little Giant vein at Arrasta Gulch, near Silverton, Colorado . The miners were allowed to stay after the Brunot Treaty of 13 Sept. 1873. In exchange for giving up 4 million acres,

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2982-580: The box as tailings . Larger commercial placer mining operations employ screening plants, or trommels , to remove the larger alluvial materials such as boulders and gravel, before concentrating the remainder in a sluice box or jig plant. After the gold is sorted through trommels, it is then placed through regular sluice boxes for further sorting. These operations typically include diesel powered, earth moving equipment including excavators, bulldozers, wheel loaders , and rock trucks. Although this method has largely been replaced by modern methods, some dredging

3053-432: The efficient capture of gold from the ore. The gold is concentrated by boiling away the mercury from the amalgam . This process is called retorting. This is effective in extracting very small gold particles, but the process is hazardous due to the toxicity of mercury vapour. Large-scale use of mercury stopped in the 1960s. However, mercury is still used in artisanal and small-scale gold mining (ASGM). While most gold

3124-465: The eight-hour day , which had been approved in a referendum by 72 percent of Colorado voters . The new association consolidated the power of thirty-six mining properties in San Miguel , Ouray , and San Juan counties. The SJDMA refused to consider any reduction in hours or increase in wages, helping to provoke a bitter strike. Summitville mine The Summitville mine was a gold mining site in

3195-762: The extraction process. This pollution can have detrimental effects on aquatic ecosystems and human health. Soil degradation has also been found to be impacted by gold mining. Mining activities can disturb soil structure, leading to erosion, sedimentation of waterways, and loss of fertile land for agriculture or vegetation regrowth. More evidently, dust and emissions from mining machiner and processing facilities can contribute to air pollution, impacting air quality and potentially causings respiratory problems for nearby communities. Large-scale gold mining projects may require land acquisition and resettlement of local communities, leading to displacement, loss of livelihoods, and disruption of traditional ways of life. In addition to

3266-694: The gold supply. Most gold is mined in developing nations. Large mining companies play a key role in globalisation of the economy by linking rich and poor companies. Newmont and Barrick Gold are the largest gold mining companies in the world, but there are many smaller corporations in the industry. Local communities are frequently vulnerable to environmental degradation caused by large mining companies and may lack government protection or industry regulation. For example, thousands of people around Lega Dembi mine are exposed to mercury, arsenic, and other toxins resulting in widespread health problems and birth defects. Vulnerable communities may also lose their land to

3337-553: The growth of cities like Melbourne and Sydney . The discovery of gold in the Witwatersrand led to the Second Boer War and ultimately the founding of South Africa. This transformed the region into one of the wealthiest gold-producing areas in the world. This rush played a crucial role in the development of South Africa's economy and lead to the establishment of Johannesburg, known as the 'city of gold'. Gold-bearing reefs in

3408-750: The heat is unbearable for humans, and air conditioning is required for the safety of the workers. The first such mine to receive air conditioning was Robinson Deep , at that time the deepest mine in the world for any mineral. Gold is also produced by mining in which it is not the principal product. Large copper mines, such as the Bingham Canyon mine in Utah, often recover considerable amounts of gold and other metals along with copper. Sand and gravel pits, like those in Denver (Colorado), may recover small amounts of gold in their wash operations. The largest producing gold mine in

3479-584: The invention of the grinding mill . Additionally, gold was associated with the sun god Ra and was believed to be eternal and indestructible, symbolising the pharoah's divine power and afterlife. Gold has also been found in the tombs of Tutankhamun and other pharoahs. During the Bronze Age, gold objects were also plentiful; especially in Ireland and Spain. Romans employed slave labour and used hydraulic mining methods, such as hushing and ground sluicing on

3550-448: The leaching continuing until March 1992, when Galactic Resources filed for bankruptcy. A total of 294,365 troy ounces (9,155.8 kg) of gold and 319,814 troy ounces (9,947.3 kg) of silver were recovered. SCMCI then closed the site and converted on-site equipment for the detoxification process, with around 160 million U.S. gallons (610,000 m ) of stored water needing treatment. After the company insolvency proceedings were completed in

3621-461: The lowest ever recorded for tropical forests, with there being little to no tree regeneration at abandoned mining camps, even after several years. The Amazon rainforest is at risk for 'savannization', which is the gradual transformation of a tropical rainforest into a savannah. This would ultimately lead to a collapse of biodiversity, ecosystems, and climate. Gold mining produces more waste than mining of other minerals, because it can be mined at

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3692-457: The mine area. The degradation in Summitville runoff water quality has its origin in both decades-old mining structures, such as the Reynold's adit, and the open-pit mining of 1985–1992. Water runoff from the Summitville mine flows down Wightman Fork, mixes with naturally acidic runoff from unmined areas, flows into the Alamosa River and flows out of the mountains into the San Luis Valley , where it

3763-663: The mine. Some large companies have attempted to build local legitimacy through corporate responsibility initiatives and local development. Gold mining can significantly alter the natural environment. Gold mining activities in tropical forests are increasingly causing deforestation along rivers and in remote areas rich in biodiversity. Mining has increased rainforest loss up to 70km beyond lease boundaries, causing nearly 11,670 km of deforestation between 2005 to 2015. Up to 9% of gold mining occurs outside of these regulated lease boundaries. Other gold mining impacts, particularly in aquatic systems with residual cyanide or mercury (used in

3834-711: The neighbouring Free State province were found shortly thereafter, driving significant development in the region with the establishment of the Free State goldfields . Also known as the Yukon Gold Rush , brought prospectors from around the world to the Klondike region of the Yukon territory in Canada . The Klondike Gold Rush began in 1896, when gold was discovered in Bonanza Creek ,

3905-675: The northern edge of the San Luis Valley, close to Poncha Pass. This suggests that early human presence in the region dates back to ancient times, long before the establishment of modern landmarks. Mining operators in the San Juan mountain area formed the San Juan District Mining Association (SJDMA) in 1903, as a direct result of a Western Federation of Miners proposal to the Telluride Mining Association for

3976-413: The old bucket line . This has improved the chances of finding gold. Smaller dredges with 50-to-100-millimetre (2 to 4 in) suction tubes are used to sample areas behind boulders and along potential pay streaks, until "colour" (gold) appears. Other larger scale dredging operations take place on exposed river gravel bars at seasonal low water. These operations typically use a land based excavator to feed

4047-481: The open-pit area and mine-waste piles from weathering and dissolution. It is likely that natural contamination adversely affected water quality and fish habitat in the Alamosa River long before and will continue to have adverse effects even when acid drainage from Summitville is remediated. Thus, reasonable natural conditions for the Alamosa River must be established in order to set realistic remediation conditions for

4118-688: The possible respiratory problems that could be acquired, individuals may be exposed to hazardous chemicals used in gold extraction such as mercury and cyanide. These chemicals pose risks to gold miners, communities, and wildlife; resulting in further medical problems involving neurological disorders and waterborne diseases . Gold mining in some regions has been associated with conflicts over land rights, labour rights violations, and exploitation of vulnerable populations, including Indigenous peoples and artisanal miners. Mining activities can damage or destroy cultural heritage sites, artifacts, and sacred areas; further impacting cultural identities and heritages. In

4189-407: The recovery of gold from ore), can be highly toxic to people and wildlife even at relatively low concentrations. Illegal gold mining exacerbates the ecological vulnerability of the remaining forest ultimately leading to permanent forest loss. Gold mining clears native forests for mineral extraction, but also indirectly facilitates access to more land and further clearing. Rainforest recovery rates are

4260-510: The site clean-up operations would halt immediately. The site clean-up was undertaken by the United States Environmental Protection Agency (EPA), from 1994 under Superfund Emergency Response . The main problem was the contaminated water held in an inadequate pond system. Another source of contamination was water leaking from older underground workings. The EPA estimated that 3,000 US gallons (11 m ) were leaking from

4331-438: The site every minute. However, despite the water having a pH of around 3 ( acidic ), a USGS study stated that the run-off was no serious threat. $ 155 million was spent on the site for detoxification and to reduce leakage. Robert Friedland , the chairman of Galactic Resources Ltd. paid around $ 30 million in settlement. Heavy metals and acid from the mine are suspected to have killed stocked fish in downstream reservoirs on

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4402-635: The site's acquisition in 1984 the last survey was in the early 1970s for copper . The total amount of gold extracted from the site from 1873 until 1959 was around 257,600 troy ounces (8,010 kg). In 1984 an area of 1,230 acres (5.0 km ) was acquired by the Canadian-based Galactic Resources Ltd. subsidiary Summitville Consolidated Mining Company, Inc. (SCMCI). They began a new large-scale open pit operation covering 550 acres (2.2 km ). New techniques were used to extract gold from otherwise uneconomic ore . The mining involved

4473-540: The sluice box. A rocker box uses less water than a sluice box and is well suited for areas where water is limited. A rocking motion provides the water movement needed for the gravity separation of gold in placer material. Rocker boxes gained popularity during the California Gold Rush in the 19th century and remain in use today. Although simple and inexpensive, it is not efficient as the previously discussed mining techniques . The dominant method for refining gold

4544-624: 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 in the gold mining industry, and can result in environmental conflict . In mines with less regulation, health and safety risks are much higher. The exact date that humans first began to mine gold

4615-467: The surrounding rock or sediments. Unlike hard-rock mining, which involves excavating solid rock formations, water or dredging is used to extract the gold. Using a sluice box to extract gold from placer deposits has long been a very common practice in prospecting and small-scale mining. Sluices work on the principle that heavier particles will sink to the bottom of a stream, while those that are lighter will be carried downstream and expelled. A sluice box

4686-457: The treatment of pyritic ore with a sodium cyanide solution to leach the gold out of the ore—heap leaching (see also cyanide process ). The solution ( leachate ) was then removed from the ore and the valuable metals extracted using activated carbon . SCMCI leached around 10 million tons of ore on a 73-acre (0.3 km ) heap leach pad. The mining operations were finished in October 1991 with

4757-474: The world's gold. Sometimes open-pit mining is used, such as at the Fort Knox Mine in central Alaska. Barrick Gold Corporation has one of the largest open-pit gold mines in North America located on its Goldstrike mine property in north eastern Nevada. Other gold mines use underground mining, where the ore is extracted through tunnels or shafts. South Africa has the world's deepest hard rock gold mine up to 3,900 metres (12,800 ft) underground. At such depths,

4828-613: The world, the Grasberg mine in Papua, Indonesia, is primarily a copper mine. Gold panning , or simply panning , is a form of placer mining and traditional mining that extracts gold from a placer deposit using a pan. The process is one of the simplest ways to extract gold, and is popular with geology enthusiasts especially because of its low cost and relative simplicity. The first recorded instances of placer mining are from ancient Rome , where gold and other precious metals were extracted from streams and mountainsides using sluices and panning ( ruina montium ). Placer mining

4899-663: Was China with 368.3 tonnes of gold mined in that year. The second-largest producer of gold was Russia where 331.1 tonnes was mined in the same year, followed by Australia with 327.8 tonnes. In 2023, the annual gold demand of 4,448 tonnes was 5% below that of 2022. The total gold demand in 2023 was the highest at 4,899 tonnes. Despite its decreasing content in ores, gold production is increasing. This increase can be achieved through ever larger-scale industrial installations as well as innovations, especially in hydrometallurgy . Hard rock mining extracts gold encased in rock, rather than fragments in loose sediment, and produces most of

4970-409: Was discovered in 1961. Official estimates indicate that total world gold production since the beginning of civilization has been around 6,352,216,000 troy ounces (197,576.0 t) and total gold production in Nevada is 1.1% of that, ranking Nevada as one of the Earth's primary gold-producing regions. World gold production was 3,612 tonnes in 2022. As of 2020 , the world's largest gold producer

5041-518: Was mined extensively. The ancient Sumerians , around 2500 BCE, developed sophisticated techniques for extracting gold from alluvial deposits and underground mines. These techniques included the use of sluice boxes. Evidence suggests that Nubia had sporadic access to gold nuggets during the Neolithic and Prehistoric Period . Gold mining in Egypt involved both surface mining such as panning for gold in riverbeads and underground mining, where tunnels were dug to extract gold-bearing quartz veins. During

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