Misplaced Pages

#338661

56-474: Gulgong Holtermann Museum is a community project and a museum space located in gold rush town of Gulgong , New South Wales . Two of the town's earliest buildings, also featured on Australian ten-dollar note (see The Greatest Wonder ) renovated and extended, house an interactive educational and tourist facility based on the UNESCO listed Holtermann Collection - photographs taken for Bernhardt Holtermann during

112-521: A Roman alluvial gold mine at Las Médulas , Spain are so spectacular as to justify the site being designated UNESCO World Heritage status. The methods used by the Roman miners are described by Pliny the Elder in his work Naturalis Historia published in about 77 AD. The author was a Procurator in the region and so probably witnessed large-scale hydraulic mining of the placer deposits there. He also added that

168-416: A few feet, or more than ten feet (a common term for one that is over six feet +/- is a "Long Tom"). While they are capable of handling a larger volume of material than simpler methods such as the rocker box or gold panning, this can come at the cost of efficiency, since conventional sluice boxes have been found to recover only about 40% of the gold that they process. The sluice box was used extensively during

224-456: A gold-bearing vein may be oxidized, so that the gold occurs as native gold, and the ore needs only to be crushed and washed (free milling ore). The first miners may at first build a simple arrastra to crush their ore; later, they may build stamp mills to crush ore at greater speed. As the miners venture downwards, they may find that the deeper part of vein contains gold locked in sulfide or telluride minerals , which will require smelting . If

280-407: A larger volume became more common. The same principle may be employed on a larger scale by constructing a short sluice box , with barriers along the bottom called riffles to trap the heavier gold particles as water washes them and the other material along the box. This method better suits excavation with shovels or similar implements to feed ore into the device. Sluice boxes can be as short as

336-809: A simple pan or equipment that may be built on the spot, and only simple organisation. The low investment, the high value per unit weight of gold, and the ability of gold dust and gold nuggets to serve as a medium of exchange, allow placer gold rushes to occur even in remote locations. After the sluice-box stage, placer mining may become increasingly large scale, requiring larger organisations and higher capital expenditures. Small claims owned and mined by individuals may need to be merged into larger tracts. Difficult-to-reach placer deposits may be mined by tunnels. Water may be diverted by dams and canals to placer mine active river beds or to deliver water needed to wash dry placers. The more advanced techniques of ground sluicing , hydraulic mining and dredging may be used. Typically

392-481: A sluice box, being fed not by a sluice but by hand. The box sits on rockers, which when rocked separates out the gold, and the practice was referred to as "rocking the golden baby". A typical rocker box is approximately 42 inches long, 16 inches wide and 12 inches deep with a removable tray towards the top, where gold is captured. The rocker was commonly used throughout North America during the early gold rush, but its popularity diminished as other methods that could handle

448-443: A stream bed. Gold accumulations in an old stream bed that are high are called bench deposits. They can be found on higher slopes that drain into valleys. Dry stream beds (benches) can be situated far from other water sources and can sometimes be found on mountaintops. Today, many miners focus their activities on bench deposits. Deep leads are created when a former stream bed is covered over by later sediments or by igneous rock from

504-423: A trough into the primary sluice box where it is filtered again. Both the grizzly and undercurrent are designed to increase efficiency, and were often used in combination. Sluicing is only effective in areas where there is a sufficient water supply, and is impractical in arid areas. Alternative methods developed that used the blowing of air to separate out gold from sand. One of the more common methods of dry washing

560-770: 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 material in an alluvial placer mine may be too loose to safely mine by tunnelling, though it

616-490: A volcanic eruption. Examples existed in the goldfields of Gulgong and Creswick in Australia. The gold bearing gravel is accessed by shafts and drives similar to underground mining techniques but is typically processed as if alluvial gold. The heat associated with an igneous lava flow, in some cases, altered the gold bearing gravel so that it needed to be crushed first to extract the gold; an example of this kind of deep lead

SECTION 10

#1733093482339

672-400: A workshop space. The museum design employs passive solar heating and natural cooling and lighting. The museum was built largely by volunteer labour. The museum, also supported by NSW Regional Cultural Fund, was visited by New South Wales premier Gladys Berejiklian and minister Troy Grant on 2 July 2018. Gulgong Holtermann Museum officially opened on 26 October 2019. Gold rush In

728-455: Is " winnowing ". This method was most commonly used by Spanish miners in America, and only requires a blanket and a box with a screen on the bottom. The material is first filtered through the box so only the finer material is placed onto the blanket. The material on the blanket is then flung into the air so that any breeze can blow away the lighter material and leave the gold behind. While this method

784-413: Is extremely simple and requires very few materials, it is also slow and inefficient. A trommel is composed of a slightly inclined rotating metal tube (the 'scrubber section') with a screen at its discharge end. Lifter bars, sometimes in the form of bolted in angle iron, are attached to the interior of the scrubber section. The ore is fed into the elevated end of the trommel. Water, often under pressure,

840-446: Is now rarely used for profit since even an expert gold prospector can only process approximately one cubic yard of material for every 10 hours of work. A rocker box (or "cradle") is capable of greater volume than a gold pan; however, its production is still limited when compared to other methods of placer mining. It is only capable of processing about 3 or 4 yards of gravel a day. It is more portable and requires less infrastructure than

896-461: Is possible where the ground is permanently frozen . Where water under pressure is available, it may be used to mine, move, and separate the precious material from the deposit, a method known as hydraulic mining , hydraulic sluicing or hydraulicking . The word placer derives from the Spanish placer , meaning shoal or alluvial/sand deposit, from plassa (place) from Medieval Latin placea (place)

952-624: Is provided to the scrubber and screen sections and the combination of water and mechanical action frees the valuable heavy minerals from the lighter gravel. The mineral bearing ore that passes through the screen is then further concentrated in smaller devices such as sluices and jigs. The larger pieces of ore that do not pass through the screen can be carried to a waste stack by a conveyor. Large-scale sifting of placer gold from large volumes of alluvial deposits can be done by use of mechanical dredges. These dredges were originally very large boats capable of processing massive amounts of material; however, as

1008-490: Is the Mexican dry wash. This method involves placing gravel on a riffle board with a bellows placed underneath it. The bellows is then used to blow air through the board in order to remove the lighter material from the heavier gold. The amount of gravel that can be processed using the Mexican dry wash technique varies from 1 1/2 to 4 cubic yards per day, and can be processed at a maximum efficiency of 80%. Another form of dry washing

1064-479: The California gold rush for larger scale operations. When streams became increasingly depleted, the grizzly and undercurrent variants of the sluice box were developed. The grizzly is a set of parallel bars placed at a 45-degree angle over the main sluice box, which filter out larger material. The undercurrent variety includes additional, auxiliary sluice boxes where material is initially filtered. It then travels through

1120-663: The Cariboo district and other parts of British Columbia, in Nevada , in the Rocky Mountains in Colorado , Idaho , Montana , eastern Oregon , and western New Mexico Territory and along the lower Colorado River . There was a gold rush in Nova Scotia (1861–1876) which produced nearly 210,000 ounces of gold. Resurrection Creek , near Hope, Alaska was the site of Alaska's first gold rush in

1176-402: The "roaring days" in the 1870s. Public launch of the museum took place on 22 January 2015. Designed by architect Jiri Lev , the museum space is formed by a series of three interconnected multi-functional pavilions built behind the restored heritage street-front buildings. The first is used as an extension of the exhibition space and for temporary exhibits, the second an event space and the third

SECTION 20

#1733093482339

1232-441: 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

1288-753: The African states, which means a huge volume of gold imports were carried out with no taxes paid to the states producing it. Ground sluicing Placer mining ( / ˈ p l æ s ər / ) is the mining of stream bed deposits for minerals . This may be done by open-pit 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

1344-455: The UAE with the exports affirmed by the African states. According to Africa's industrial mining firms, they have not exported any amount of gold to the UAE – confirming that the imports come from other, illegal sources. As per customs data, the UAE imported gold worth $ 15.1 billion from Africa in 2016, with a total weight of 446 tons, in variable degrees of purity. Much of the exports were not recorded in

1400-790: The United States was in Cabarrus County, North Carolina (east of Charlotte), in 1799 at today's Reed's Gold Mine . Thirty years later, in 1829, the Georgia Gold Rush in the southern Appalachians occurred. It was followed by the California Gold Rush of 1848–55 in the Sierra Nevada , which captured the popular imagination. The California Gold Rush led to an influx of gold miners and newfound gold wealth, which led to California's rapid industrialization, as businesses sprung up to serve

1456-498: The Wild , which had much success during the period. Gold rushes occurred as early as the times of ancient Greece , whose gold mining was described by Diodarus Sicules and Pliny the Elder . Within each mining rush there is typically a transition through progressively higher capital expenditures, larger organizations, and more specialized knowledge. A rush typically begins with the discovery of placer gold made by an individual. At first

1512-458: The Yukon, placer deposits may be mined underground. As the frozen ground is otherwise too hard and firm to mine by hand, historically fires were built so as to thaw the ground before digging it. Later methods involve blasting jets of steam ("points") into the frozen deposits. Deep leads are accessed by techniques similar to conventional underground mining. Although this procedure is not required,

1568-486: The culture of the Australian and North American frontiers . At a time when the world's money supply was based on gold , the newly-mined gold provided economic stimulus far beyond the goldfields, feeding into local and wider economic booms . The Gold Rush was a topic that inspired many TV shows and books considering it was a very important topic at the time. During the time, many books were published including The Call of

1624-564: The flow of water is a great location to find gold. Gold is very dense and is often found in a stream bed. Many different gold deposits are dealt with in different ways. Placer deposits attract many prospectors because their costs are very low. There are many different places gold could be placed, such as a residual, alluvial, and a bench deposit. Residual deposits are more common where there has been weathering on rocks and where there hasn't been water. They are deposits which have not been washed away yet or been moved. The residual usually lies at

1680-422: The focus may change progressively from gold to silver to base metals. In this way, Leadville, Colorado started as a placer gold discovery, achieved fame as a silver-mining district, then relied on lead and zinc in its later days. Butte, Montana began mining placer gold, then became a silver-mining district, then became for a time the world's largest copper producer. Various gold rushes occurred in Australia over

1736-548: The gold fields, material that was carried downstream and raised the level of portions of the Central Valley by some seven feet in affected areas and settled in long bars up to 20 feet thick in parts of San Francisco Bay . The process raised an opposition calling themselves the "Anti-Debris Association". In January 1884, the North Bloomfield Mining and Gravel Company case banned the flushing of debris into streams, and

Gulgong Holtermann Museum - Misplaced Pages Continue

1792-488: The gold for a large part of the ancient world. Hydraulic mining methods such as hushing were used widely by the Romans across their empire, but especially in the gold fields of northern Spain after its conquest by Augustus in 25 BC. One of the largest sites was at Las Médulas , where seven 30 mile long aqueducts were used to work the alluvial gold deposits through the first century AD. In North America , placer mining

1848-476: The gold has become increasingly depleted in the most easily accessible areas, smaller and more maneuverable dredges have become much more common. These smaller dredges commonly operate by sucking water and gravel up through long hoses using a pump, where the gold can then be separated using more traditional methods such as a sluice box. In areas where the ground is permanently frozen , such as in Siberia, Alaska, and

1904-459: The gold may be washed from the sand and gravel by individual miners with little training, using a gold pan or similar simple instrument. Once it is clear that the volume of gold-bearing sediment is larger than a few cubic metres, the placer miners will build rockers or sluice boxes, with which a small group can wash gold from the sediment many times faster than using gold pans. Winning the gold in this manner requires almost no capital investment, only

1960-437: The heyday of a placer gold rush would last only a few years. The free gold supply in stream beds would become depleted somewhat quickly, and the initial phase would be followed by prospecting for veins of lode gold that were the original source of the placer gold. Hard rock mining, like placer mining, may evolve from low capital investment and simple technology to progressively higher capital and technology. The surface outcrop of

2016-536: The increased population and financial and political institutions to handle the increased wealth. One of these political institutions was statehood; the need for new laws in a sparsely-governed land led to the state's rapid entry into the Union in 1850. The gold rush in 1849 also stimulated worldwide interest in prospecting for gold, leading to further rushes in Australia, South Africa, Wales and Scotland. Successive gold rushes occurred in western North America: Fraser Canyon ,

2072-545: The local lake Carucedo had been heavily silted by the mining methods. Environmental activists describe the hydraulic mining form of placer mining as environmentally destructive because of the large amounts of silt that it adds to previously clear running streams (also known as the "Dahlonega Method"). Most placer mines today use settling ponds , if only to ensure that they have sufficient water to run their sluicing operations. In California, from 1853 to 1884, "hydraulicking" of placers removed an enormous amount of material from

2128-554: 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 mobility , in which any single individual might become abundantly wealthy almost instantly, as expressed in the California Dream . Gold rushes helped spur waves of immigration that often led to the permanent settlement of new regions. Activities propelled by gold rushes define significant aspects of

2184-667: The mid–1890s. Other notable Alaska Gold Rushes were Nome , Fairbanks , and the Fortymile River . One of the last "great gold rushes" was the Klondike Gold Rush in the Yukon Territory (1896–99). This gold rush is featured in the novels of Jack London , and Charlie Chaplin 's film The Gold Rush . Robert William Service depicted in his poetries the Gold Rush, especially in the book The Trail of '98 . The main goldfield

2240-456: The minerals from the ground, and separating it from the non-gold or non-gems. The simplest technique to extract gold from placer ore is panning . This technique has been dated back to at least the Roman Empire. In panning, some mined ore is placed in a large metal or plastic pan, combined with a generous amount of water , and agitated so that the gold particles, being of higher density than

2296-610: The new arrivals who came looking for gold. While some found their fortune, those who did not often remained in the colonies and took advantage of extremely liberal land laws to take up farming. Gold rushes happened at or around: In New Zealand the Otago gold rush from 1861 attracted prospectors from the California gold rush and the Victorian gold rush and many moved on to the West Coast gold rush from 1864. The first significant gold rush in

Gulgong Holtermann Museum - Misplaced Pages Continue

2352-465: The ore is still sufficiently rich, it may be worth shipping to a distant smelter (direct shipping ore). Lower-grade ore may require on-site treatment to either recover the gold or to produce a concentrate sufficiently rich for transport to the smelter. As the district turns to lower-grade ore, the mining may change from underground mining to large open-pit mining . Many silver rushes followed upon gold rushes. As transportation and infrastructure improve,

2408-501: The origin word for "place" and "plaza" in English. The word in Spanish is thus derived from placea and refers directly to an alluvial or glacial deposit of sand or gravel. An alternative etymology derives the English word from American Spanish placer (placer, sandbank), from earlier placel , apparently from obsolete Portuguese placel (placer, sandbank). Placers supplied most of

2464-430: The other material, settle to the bottom of the pan. The lighter gangue material such as sand, mud and gravel are then washed over the side of the pan, leaving the gold behind. Once a placer deposit is located by gold panning, the miner usually shifts to equipment that can treat volumes of sand and gravel more quickly and efficiently. Gold panning was commonly used on its own during the California gold rush ; however, it

2520-403: The process water may be continuously recycled and the ore from which the sought-after minerals have been extracted ("the tailings") can be reclaimed. While these recycling and reclamation processes are more common in modern placer mining operations they are still not universally done. In earlier times the process water was not generally recycled and the spent ore was not reclaimed. The remains of

2576-644: The region. The gold deposits in this area are identified as one of the largest in the world. In South Africa, the Witwatersrand Gold Rush in the Transvaal was important to that country's history, leading to the founding of Johannesburg and tensions between the Boers and British settlers as well as the Chinese miners. South African gold production went from zero in 1886 to 23% of the total world output in 1896. At

2632-537: The second half of the 19th century. The most significant of these, although not the only ones, were the New South Wales gold rush and Victorian gold rush in 1851, and the Western Australian gold rushes of the 1890s. They were highly significant to their respective colonies' political and economic development as they brought many immigrants, and promoted massive government spending on infrastructure to support

2688-453: The site of the lode. This type of deposit undergoes rock weathering. Alluvial or eluvial deposits are the most common type of placer gold, and are often the richest. They contain pieces of gold that have been washed away from the lode by the force of water, and have been deposited in sediment in or near watercourses or former watercourses. Therefore, they are mostly found in valleys or flood plains. Bench deposits are created when gold reaches

2744-575: The smuggling of billions of dollars' worth of gold out of Africa through the United Arab Emirates in the Middle East , which further acts as a gateway to the markets in the United States , Europe and more. The news agency evaluated the worth and magnitude of illegal gold trade occurring in African nations like Ghana , Tanzania , and Zambia , by comparing the total gold imports recorded into

2800-546: The time of the South African rush, gold production benefited from the newly discovered techniques by Scottish chemists, the MacArthur-Forrest process , of using potassium cyanide to extract gold from low-grade ore. The gold mine at El Callao (Venezuela), started in 1871, was for a time one of the richest in the world, and the goldfields as a whole saw over a million ounces exported between 1860 and 1883. The gold mining

2856-575: The world, according to Communities and Small-Scale Mining (CASM). Approximately 100 million people are directly or indirectly dependent on small-scale mining. For example, there are 800,000 to 1.5 million artisanal miners in Democratic Republic of Congo , 350,000 to 650,000 in Sierra Leone , and 150,000 to 250,000 in Ghana , with millions more across Africa. In an exclusive report, Reuters accounted

SECTION 50

#1733093482339

2912-764: Was along the south flank of the Klondike River near its confluence with the Yukon River near what was to become Dawson City in Yukon Territory, but it also helped open up the relatively new US possession of Alaska to exploration and settlement, and promoted the discovery of other gold finds. The most successful of the North American gold rushes was the Porcupine Gold Rush in Timmins, Ontario area. This gold rush

2968-661: Was dominated by immigrants from the British Isles and the British West Indies, giving an appearance of almost creating an English colony on Venezuelan territory. Between 1883 and 1906 Tierra del Fuego experienced a gold rush attracting many Chileans, Argentines and Europeans to the archipelago. The gold rush began in 1884 following discovery of gold during the rescue of the French steamship Arctique near Cape Virgenes . There are about 10 to 30 million small-scale miners around

3024-648: Was famous in the context of several gold rushes , particularly the California Gold Rush and the Colorado Gold Rush , the Fraser Canyon Gold Rush and the Klondike Gold Rush . Placer mining continues in many areas of the world as a source of diamonds, industrial minerals and metals, gems (in Myanmar and Sri Lanka ), platinum, and of gold (in Yukon , Alaska and British Columbia ). An area well protected from

3080-416: Was found at Forest Reefs , also in Australia. If vegetation was buried along with the old stream, by a volcanic eruption, the effect of heat and decay upon that buried vegetation can result in the presence of harmful amounts of carbonic acid gas ( H 2 C O 3 ), as occurred in the deep lead deposit at Creswick. A number of methods are used to mine placer gold and gems, both in terms of extracting

3136-493: Was unique compared to others by the method of extraction of the gold. Placer mining techniques were not able to be used to access the gold in the area due to it being embedded into the Canadian Shield , so larger mining operations involving significantly more expensive equipment was required. While this gold rush peaked in the 1940s and 1950s, it is still active today with over 200 million ounces of gold having been produced from

#338661