1.
Tailings dam
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A tailings dam is typically an earth-fill embankment dam used to store byproducts of mining operations after separating the ore from the gangue. Conventional water retention dams can serve this purpose, but due to cost, Tailings can be liquid, solid, or a slurry of fine particles. Solid tailings are used as part of the structure itself. Tailings dams rank among the largest engineered structures on earth, the Syncrude Mildred Lake Tailings Dyke in Alberta, Canada, is an embankment dam about 18 kilometres long and from 40 to 88 metres high. It is the largest dam structure on earth by volume, there are key differences between tailings dams and the more familiar hydro dams. Tailings dams are designed for permanent containment, meant to remain there forever, copper, gold, uranium and other mining operations produce varied kinds of waste, much of it toxic, which pose varied challenges for long-term containment. An estimated 3,500 active tailings impoundments stand around the world, although there is no complete inventory, as of 2000 these structures experience known major failures of about 2 to 5 annually, along with 35 minor failures. Assuming the 3,500 figure is correct, this rate is more than two orders of magnitude higher than the failure rate of conventional water retention dams. Unlike water retention dams, a dam is raised in succession throughout the life of the particular mine. Typically, a base or starter dam is constructed, and as it fills with a mixture of tailings and water, material used to raise the dam can include the tailings along with dirt. There are three raised tailings dam designs, the upstream, downstream and centerline, named according to the movement of the crest during raising, the specific design used is dependent upon topography, geology, climate, the type of tailings, and cost. An upstream tailings dam consists of trapezoidal embankments being constructed on top but toe to crest of another and this creates a relatively flat downstream side and a jagged upstream side which is supported by tailings slurry in the impoundment. The downstream design refers to the raising of the embankment that positions the fill. A centerlined dam has sequential embankment dams constructed directly on top of another while fill is placed on the side for support. Type, TE - Earth, ER - Rock-fill, PG - Concrete gravity, a large number remain completely unreported, or lack basic facts when reported. There is no database for historic failures. The lack of any comprehensive tailings dam database has prevented meaningful analysis, the mining and processing byproducts collected in tailings dams are not part of the aerobic ecological systems, and are unstable. They may damage the environment by releasing toxic metals, by acid drainage, history Tailings ponds can also be a source of acid drainage, leading to the need for permanent monitoring and treatment of water passing through the tailings dam
Tailings dam
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Glen Canyon Dam
Tailings dam
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A sideview of the Lake Vyrnwy dam, in Wales, finished in 1888
Tailings dam
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Karapuzha Dam, an earth dam in the Indian state of Kerala
Tailings dam
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The Roman dam at Cornalvo in Spain has been in use for almost two millennia
2.
Eureka County
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Eureka County is a county located in the U. S. state of Nevada. As of the 2010 census, the population was 1,987, Eureka County is part of the Elko Micropolitan Statistical Area. Eureka County was established in 1873 and formed from Lander County after silver was discovered more than 100 miles east of Austin, the residents of the new mining camp complained that Austin was too far to go for county business and a new county was created. It was named for the ancient Greek term, Eureka, meaning and this term was used earlier in California and other locations. Eureka has always been the county seat, according to the U. S. Census Bureau, the county has a total area of 4,180 square miles, of which 4,176 square miles is land and 4.3 square miles is water. The highest point in the county is the 10,631 ft summit of Diamond Peak in the Diamond Mountains along the border with White Pine County, the population density was 0.39 people per square mile. There were 1,025 housing units at a density of 0.25 per square mile. 29. 10% of all households were made up of individuals and 9. 90% had someone living alone who was 65 years of age or older, the average household size was 2.47 and the average family size was 3.08. In the county, the population was out with 27. 80% under the age of 18,5. 20% from 18 to 24,28. 60% from 25 to 44,25. 90% from 45 to 64. The median age was 38 years, for every 100 females there were 106.60 males. For every 100 females age 18 and over, there were 113.20 males, the median income for a household in the county was $41,417, and the median income for a family was $49,438. Males had an income of $45,167 versus $25,000 for females. The per capita income for the county was $18,629,12. 60% of the population and 8. 90% of families were below the poverty line. Out of the people living in poverty,11. 70% are under the age of 18 and 16. 40% are 65 or older. As of the 2010 United States Census, there were 1,987 people,836 households, the population density was 0.5 inhabitants per square mile. There were 1,076 housing units at a density of 0.3 per square mile. The racial makeup of the county was 89. 3% white,2. 4% American Indian,0. 9% Asian,0. 1% black or African American,5. 1% from other races, and 2. 2% from two or more races. Those of Hispanic or Latino origin made up 12. 0% of the population, in terms of ancestry,43. 3% were American,14. 8% were German,11. 4% were Irish,7. 3% were English, and 6. 9% were Italian
Eureka County
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Location in the state of Nevada
3.
Nevada
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Nevada is a state in the Western, Mountain West, and Southwestern regions of the United States of America. Nevada is the 7th most extensive, the 34th most populous, nearly three-quarters of Nevadas people live in Clark County, which contains the Las Vegas–Paradise metropolitan area where three of the states four largest incorporated cities are located. Nevada is officially known as the Silver State because of the importance of silver to its history and economy. It is also known as the Battle Born State, because it achieved statehood during the Civil War, as the Sage-brush State, for the plant of the same name. Nevada borders Oregon to the northwest, Idaho to the northeast, California to the west, Arizona to the southeast, Nevada is largely desert and semi-arid, much of it located within the Great Basin. Areas south of the Great Basin are located within the Mojave Desert, while Lake Tahoe, about 86% of the states land is managed by various jurisdictions of the U. S. federal government, both civilian and military. Before European contact, Native Americans of the Paiute, Shoshone, the first Europeans to explore the region were Spanish. They called the region Nevada because of the snow covered the mountains in winter. The area formed part of the Viceroyalty of New Spain, the United States annexed the area in 1848 after its victory in the Mexican–American War, and it was incorporated as part of Utah Territory in 1850. The discovery of silver at the Comstock Lode in 1859 led to a boom that became an impetus to the creation of Nevada Territory out of western Utah Territory in 1861. Nevada became the 36th state on October 31,1864, as the second of two added to the Union during the Civil War. Nevada has a reputation for its libertarian laws, in 1940, with a population of just over 110,000 people, Nevada was by far the least-populated state, with less than half the population of the next least-populated state. However, legalized gambling and lenient marriage and divorce laws transformed Nevada into a major tourist destination in the 20th century, Nevada is the only U. S. state where prostitution is legal, though it is illegal in Clark County, Washoe County and Carson City. The tourism industry remains Nevadas largest employer, with mining continuing as a sector of the economy. The name Nevada comes from the Spanish nevada, meaning snow-covered, most Nevadans pronounce the second syllable of their state name using the vowel of trap. Many from outside the Western United States pronounce it with the vowel of father, although the latter pronunciation is closer to the Spanish pronunciation, it is not the pronunciation preferred by most Nevadans. State Assemblyman Harry Mortenson proposed a bill to recognize the alternate pronunciation of Nevada, though the bill was not supported by most legislators, the Nevadan pronunciation is the de facto official one, since it is the one used by the state legislature. Nevada is almost entirely within the Basin and Range Province, and is broken up by many mountain ranges
Nevada
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The quartzite of the Prospect Mountain Formation on top of Jeff Davis Peak in Great Basin National Park
Nevada
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Flag
Nevada
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Mountains west of Las Vegas in the Mojave Desert
Nevada
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Vegetation at Timber Creek in the Schell Creek Range
4.
United States
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Forty-eight of the fifty states and the federal district are contiguous and located in North America between Canada and Mexico. The state of Alaska is in the northwest corner of North America, bordered by Canada to the east, the state of Hawaii is an archipelago in the mid-Pacific Ocean. The U. S. territories are scattered about the Pacific Ocean, the geography, climate and wildlife of the country are extremely diverse. At 3.8 million square miles and with over 324 million people, the United States is the worlds third- or fourth-largest country by area, third-largest by land area. It is one of the worlds most ethnically diverse and multicultural nations, paleo-Indians migrated from Asia to the North American mainland at least 15,000 years ago. European colonization began in the 16th century, the United States emerged from 13 British colonies along the East Coast. Numerous disputes between Great Britain and the following the Seven Years War led to the American Revolution. On July 4,1776, during the course of the American Revolutionary War, the war ended in 1783 with recognition of the independence of the United States by Great Britain, representing the first successful war of independence against a European power. The current constitution was adopted in 1788, after the Articles of Confederation, the first ten amendments, collectively named the Bill of Rights, were ratified in 1791 and designed to guarantee many fundamental civil liberties. During the second half of the 19th century, the American Civil War led to the end of slavery in the country. By the end of century, the United States extended into the Pacific Ocean. The Spanish–American War and World War I confirmed the status as a global military power. The end of the Cold War and the dissolution of the Soviet Union in 1991 left the United States as the sole superpower. The U. S. is a member of the United Nations, World Bank, International Monetary Fund, Organization of American States. The United States is a developed country, with the worlds largest economy by nominal GDP. It ranks highly in several measures of performance, including average wage, human development, per capita GDP. While the U. S. economy is considered post-industrial, characterized by the dominance of services and knowledge economy, the United States is a prominent political and cultural force internationally, and a leader in scientific research and technological innovations. In 1507, the German cartographer Martin Waldseemüller produced a map on which he named the lands of the Western Hemisphere America after the Italian explorer and cartographer Amerigo Vespucci
United States
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Native Americans meeting with Europeans, 1764
United States
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Flag
United States
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The signing of the Mayflower Compact, 1620.
United States
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The Declaration of Independence: the Committee of Five presenting their draft to the Second Continental Congress in 1776
5.
Geographic coordinate system
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A geographic coordinate system is a coordinate system used in geography that enables every location on Earth to be specified by a set of numbers, letters or symbols. The coordinates are chosen such that one of the numbers represents a vertical position. A common choice of coordinates is latitude, longitude and elevation, to specify a location on a two-dimensional map requires a map projection. The invention of a coordinate system is generally credited to Eratosthenes of Cyrene. Ptolemy credited him with the adoption of longitude and latitude. Ptolemys 2nd-century Geography used the prime meridian but measured latitude from the equator instead. Mathematical cartography resumed in Europe following Maximus Planudes recovery of Ptolemys text a little before 1300, in 1884, the United States hosted the International Meridian Conference, attended by representatives from twenty-five nations. Twenty-two of them agreed to adopt the longitude of the Royal Observatory in Greenwich, the Dominican Republic voted against the motion, while France and Brazil abstained. France adopted Greenwich Mean Time in place of local determinations by the Paris Observatory in 1911, the latitude of a point on Earths surface is the angle between the equatorial plane and the straight line that passes through that point and through the center of the Earth. Lines joining points of the same latitude trace circles on the surface of Earth called parallels, as they are parallel to the equator, the north pole is 90° N, the south pole is 90° S. The 0° parallel of latitude is designated the equator, the plane of all geographic coordinate systems. The equator divides the globe into Northern and Southern Hemispheres, the longitude of a point on Earths surface is the angle east or west of a reference meridian to another meridian that passes through that point. All meridians are halves of great ellipses, which converge at the north and south poles, the prime meridian determines the proper Eastern and Western Hemispheres, although maps often divide these hemispheres further west in order to keep the Old World on a single side. The antipodal meridian of Greenwich is both 180°W and 180°E, the combination of these two components specifies the position of any location on the surface of Earth, without consideration of altitude or depth. The grid formed by lines of latitude and longitude is known as a graticule, the origin/zero point of this system is located in the Gulf of Guinea about 625 km south of Tema, Ghana. To completely specify a location of a feature on, in, or above Earth. Earth is not a sphere, but a shape approximating a biaxial ellipsoid. It is nearly spherical, but has an equatorial bulge making the radius at the equator about 0. 3% larger than the radius measured through the poles, the shorter axis approximately coincides with the axis of rotation
Geographic coordinate system
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Longitude lines are perpendicular and latitude lines are parallel to the equator.
6.
Gold
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Gold is a chemical element with symbol Au and atomic number 79. In its purest form, it is a bright, slightly yellow, dense, soft, malleable. Chemically, gold is a 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 form, as nuggets or grains, in rocks, in veins, and in alluvial deposits. It occurs in a solid solution series with the element silver and also naturally alloyed with copper. Less commonly, it occurs in minerals as gold compounds, often with tellurium, golds atomic number of 79 makes it one of the higher numbered, naturally occurring elements. It is thought to have produced in supernova nucleosynthesis, from the collision of neutron stars. Because the Earth was molten when it was formed, almost all of the present in the early Earth probably sank into the planetary core. Gold is resistant to most acids, though it does dissolve in aqua regia, a mixture of acid and hydrochloric acid. Gold also dissolves in solutions of cyanide, which are used in mining and electroplating. Gold dissolves in mercury, forming amalgam alloys, but this is not a chemical reaction, as a precious metal, gold has been used for coinage, jewelry, and other arts throughout recorded history. A total of 186,700 tonnes of gold is in existence above ground, the world consumption of new gold produced is about 50% in jewelry, 40% in investments, and 10% in industry. Gold is also used in infrared shielding, colored-glass production, gold leafing, certain gold salts are still used as anti-inflammatories in medicine. As of 2014, the worlds largest gold producer by far was China with 450 tonnes, Gold is cognate with similar words in many Germanic languages, deriving via Proto-Germanic *gulþą from Proto-Indo-European *ǵʰelh₃-. The symbol Au is from the Latin, aurum, the Latin word for gold, the Proto-Indo-European ancestor of aurum was *h₂é-h₂us-o-, meaning glow. This word is derived from the root as *h₂éu̯sōs, the ancestor of the Latin word Aurora. This etymological relationship is presumably behind the frequent claim in scientific publications that aurum meant shining dawn, Gold is the most malleable of all metals, a single gram can be beaten into a sheet of 1 square meter, and an avoirdupois ounce into 300 square feet. Gold leaf can be thin enough to become semi-transparent
Gold
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Gold, 79 Au
Gold
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Moche gold necklace depicting feline heads. Larco Museum Collection. Lima-Peru
Gold
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Mirror for the future James Webb Space Telescope coated in gold to reflect infrared light
Gold
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The world's largest gold bar has a mass of 250 kg. Toi museum, Japan.
7.
Barrick Gold
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Barrick Gold Corporation is the largest gold mining company in the world, with its headquarters in Toronto, Ontario, Canada. Barrick is currently undertaking mining projects in Argentina, Australia, Canada, Chile, the Dominican Republic, Papua New Guinea, Peru, Saudi Arabia, the United States and Zambia. For 2013, it produced 7.2 million ounces of gold at all-in sustaining costs of US $915/ounce and 539 million pounds of copper at C1 cash costs of $1. 92/pound. As of December 31,2013, its proven and probable reserves were 104.1 million ounces of gold,888 million ounces of silver contained within gold reserves. On January 20,2006, Barrick acquired a majority share of Placer Dome, the production of the combined organization moved Barrick to its current position as the largest gold producer, ahead of Newmont Mining Corporation. In 2016 Barrick produced 5.52 million ounces of gold at all-in sustaining costs of $730 per ounce, copper production for the year totaled 415 million pounds at all-in sustaining cash costs of $2.05 per pound. Barrick Gold Corporation evolved from a privately held North American oil and gas company, after suffering huge financial losses in oil and gas, principal Peter Munk decided to focus on gold. Barrick Resources Corporation became a traded company on May 2,1983. The company’s first acquisition was the Renabie mine, near Wawa, Ontario, which produced around 16,000 troy ounces of gold in 1984, but its best year was 1990 with 48,000 ounces produced. In 1984, Barrick acquired Camflo Mining, which had operations in the province of Quebec, barrick’s effort to purchase was slowed by skepticism the company could assume Camflo’s debt of around $100 million. The sale was finalized in May 1984, with terms that obligated Barrick to repay the debt to The Royal Bank of Canada within one year, the debt was fully paid in January 1985. Barrick Resource’s next acquisition was the Mercur mine in Mercur, Utah, in June 1985, followed by the Goldstrike mine, in Nevada, the Goldstrike mine is located on the Carlin Trend. The company’s name was changed to American Barrick Resources in 1986 and it was listed on the New York Stock Exchange in February 1987. The name was changed to the present Barrick Gold Corporation in 1995, a third acquisition followed in early 1999, when Barrick Gold acquired Sutton Resources Ltd. for around $350 million in stock, assuming ownership of properties in Tanzania. In 2001 Barrick Gold made another deal, worth about USD $2.3 billion, to buy the Homestake Mining Company. The purchase moved Barrick to second largest gold producer in the world, the company offered US $9.2 billion for Placer Dome Inc. in a bid announced October 31,2005. During the following weeks, Placer Dome recommended shareholders reject the offer, in December, Placer Dome’s board of directors approved an increased offer worth US $10.4 billion. The transaction closed in early 2006, making Barrick the world’s largest gold producer, on July 24,2006, Barrick announced their intent to purchase NovaGold Resources and Pioneer Metals
Barrick Gold
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The Super Pit gold mine
Barrick Gold
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Barrick Gold Corporation
Barrick Gold
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Looking down into the Porgera open pit.
8.
Millerite
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Millerite is a nickel sulfide mineral, NiS. It is brassy in colour and has a habit, often forming radiating masses. It can be distinguished from pentlandite by crystal habit, its duller colour, millerite is a common metamorphic mineral replacing pentlandite within serpentinite ultramafics. It is formed in this way by removal of sulfur from pentlandite or other nickeliferous sulfide minerals during metamorphism or metasomatism, millerite is also formed from sulfur poor olivine cumulates by nucleation. Millerite is thought to form from sulfur and nickel which exist in pristine olivine in trace amounts, magmatic olivine generally has up to ~4000 ppm Ni and up to 2500 ppm S within the crystal lattice, as contaminants and substituting for other transition metals with similar ionic radii. During metamorphism, sulfur and nickel within the lattice are reconstituted into metamorphic sulfide minerals, chiefly millerite, during serpentinization. This forms disseminated needle like millerite crystals dispersed throughout the rock mass, millerite may be associated with heazlewoodite and is considered a transitional stage in the metamorphic production of heazlewoodite via the above process. Millerite, when found in concentration, is a very important ore of nickel because, for its mass as a sulfide mineral. This means that, for every percent of millerite, an ore contains more nickel than an equivalent percentage of pentlandite sulfide, millerite forms an important ore constituent of the Silver Swan, Wannaway, Cliffs, Honeymoon Well, Yakabindie and Mt Keith orebodies. It is an accessory mineral associated with nickel laterite deposits in New Caledonia, there is one known occurrence of millerite in South Africa, near Pafuri in the Transvaal. The deposit has never been commercially mined and it is commonly found as radiating clusters of acicular needle-like crystals in cavities in sulfide rich limestone and dolomite or in geodes. It is also found in meteorites, such as CK carbonaceous chondrites. Millerite was discovered by Wilhelm Haidinger in 1845 in the mines of Wales. It was named for British mineralogist William Hallowes Miller, the mineral is quite rare in specimen form, and the most common source of the mineral is in the Halls Gap area of Lincoln County, Kentucky in the United States. List of minerals List of minerals named after people Mineral galleries Wisconsin minerals University of Kentucky, Kentucky Geological Survey, Sulfide Minerals
Millerite
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Millerite needles in a quartz geode. Locality: Halls Gap, Lincoln County, Kentucky. Size: 4.0 x 3.5 x 3.0 cm
Millerite
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Millerite structure
Millerite
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Lustrous mass of intergrown millerite needles from Kalgoorlie, Western Australia. (size: 3.9 x 3.5 x 2.2 cm)
9.
Pyrite
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The mineral pyrite, or iron pyrite, also known as fools gold, is an iron sulfide with the chemical formula FeS2. This minerals metallic luster and pale brass-yellow hue give it a resemblance to gold. The color has led to the nicknames brass, brazzle. Pyrite is the most common of the sulfide minerals, the name pyrite is derived from the Greek πυρίτης, of fire or in fire, in turn from πύρ, fire. 1550, the term had become a term for all of the sulfide minerals. Pyrite is usually associated with other sulfides or oxides in quartz veins, sedimentary rock. Despite being nicknamed fools gold, pyrite is sometimes found in association with small quantities of gold, Gold and arsenic occur as a coupled substitution in the pyrite structure. In the Carlin–type gold deposits, arsenian pyrite contains up to 0.37 wt% gold, Pyrite has been used since classical times to manufacture copperas, that is, iron sulfate. Iron pyrite was heaped up and allowed to weather, the acidic runoff from the heap was then boiled with iron to produce iron sulfate. In the 15th century, such leaching began to replace the burning of sulfur as a source of sulfuric acid, by the 19th century, it had become the dominant method. Pyrite remains in use for the production of sulfur dioxide, for use in such applications as the paper industry. Thermal decomposition of pyrite into FeS and elemental sulfur starts at 540 °C, a newer commercial use for pyrite is as the cathode material in Energizer brand non-rechargeable lithium batteries. Pyrite is a material with a band gap of 0.95 eV. During the early years of the 20th century, pyrite was used as a detector in radio receivers. Pyrite detectors occupied a midway point between galena detectors and the more mechanically complicated perikon mineral pairs, Pyrite detectors can be as sensitive as a modern 1N34A germanium diode detector. Pyrite has been proposed as an abundant, inexpensive material in low-cost photovoltaic solar panels, synthetic iron sulfide was used with copper sulfide to create the photovoltaic material. Pyrite is used to make marcasite jewelry, marcasite jewelry, made from small faceted pieces of pyrite, often set in silver, was known since ancient times and was popular in the Victorian era. Marcasite jewelry does not actually contain the mineral marcasite, from the perspective of classical inorganic chemistry, which assigns formal oxidation states to each atom, pyrite is probably best described as Fe2+S22−
Pyrite
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Pyrite cubic crystals on marl from Navajún, La Rioja, Spain (size: 95 by 78 millimetres (3.7 by 3.1 in), 512 grams (18.1 oz); main crystal: 31 millimetres (1.2 in) on edge)
Pyrite
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Pyrite from Ampliación a Victoria Mine, Navajún, La Rioja, Spain.
Pyrite
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Dodecahedron - shaped crystals from Italy.
Pyrite
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A pyrite cube (center) has dissolved away from a host rock, leaving behind trace gold.
10.
Gold mine
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Gold mining is the resource extraction of gold by mining. As of 2015, the worlds largest gold producer by far was China with 455 tonnes, the second-largest producer, Australia, mined 270 tonnes in the same year, followed by Russia with 250 tonnes. It is impossible to know the date that humans first began to mine gold. The graves of the necropolis were built between 4700 and 4200 BC, indicating that gold mining could be at least 7000 years old. A group of German and Georgian archaeologists claims the Sakdrisi site in southern Georgia, dating to the 3rd or 4th millennium BC, bronze age gold objects are plentiful, especially in Ireland and Spain, and there are several well known possible sources. Romans used hydraulic mining methods, such as hushing and ground sluicing on a scale to extract gold from extensive alluvial deposits. Mining was under the control of the state but the mines may have been leased to civilian contractors some time later, 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 Trajans Column in Rome, under the Eastern Roman Empire Emperor Justinians 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. The Champion reef at the Kolar gold fields was mined to a depth of 50 metres 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 it is estimated that the total gold production in Karnataka to date is 1000 tons. The mining of the Slovak deposit primarily around Kremnica was the largest of the Medieval period in Europe, the discovery of gold in the Witwatersrand led to the Second Boer War and ultimately the founding of South Africa. The Carlin Trend of Nevada, U. S. was discovered in 1961, as of 2015, the worlds largest gold producer by far was China with 455 tonnes/year. The second-largest producer, Australia, mined 270 tonnes in the same year, despite the decreasing gold content of ores, the production is increasing. This can be achieved with industrial installations, and new process, placer mining is the technique by which gold that has accumulated in a placer deposit is extracted. Placer deposits are composed of loose material that makes tunneling difficult. Gold panning is mostly a manual technique of separating gold from other materials, wide, shallow pans are filled with sand and gravel that may contain gold. The pan is submerged in water and shaken, sorting the gold from the gravel, as gold is much denser than rock, it quickly settles to the bottom of the pan
Gold mine
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Super Pit gold mine in Western Australia
Gold mine
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Gold-bearing quartz veins in Alaska
Gold mine
Gold mine
11.
Heap leach
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The solution then percolates through the heap and leaches both the target and other minerals. This process, called the cycle, generally takes from one or two months for simple oxide ores to two years. Ultimate recovery of the mineral can range from 30% of contained to over 90% for the easiest to leach ores. In recent years, the addition of a drum has improved on the heap leaching process by allowing for a more efficient leach. The rotary drum agglomerator, such as the tyre driven Sepro Agglomeration Drum works by taking the crushed ore fines and this makes it much easier for the leaching solution to percolate through the pile, making its way through the channels between particles. The dismissal of these mechanisms can result in a number of practical and financial problems that will resonate throughout the life of the heap impacting the financial return of the operation, the crushed ore is irrigated with a dilute alkaline cyanide solution. The solution containing the precious metals continues percolating through the crushed ore until it reaches the liner at the bottom of the heap where it drains into a storage pond. The production of one gold ring through this method, can generate 20 tons of waste material, the fine product can be either doré or zinc-gold sludge that is then refined elsewhere. The method is similar to the method, above, except sulfuric acid is used to dissolve copper from its ores. The acid is recycled from the solvent extraction circuit and reused on the leach pad, a byproduct is iron sulfate, jarosite, which is produced as a byproduct of leaching pyrite, and sometimes even the same sulfuric acid that is needed for the process. Both oxide and sulfide ores can be leached, though the leach cycles are much different, in 2011 leaching produced 3.4 million metric tons of copper,22 percent of world production. The largest copper heap leach operations are in Chile, Peru, although the heap leaching is a low cost-process, it normally has recovery rates of 60-70%, although there are exceptions. It is normally most profitable with low-grade ores, higher-grade ores are usually put through more complex milling processes where higher recoveries justify the extra cost. The process chosen depends on the properties of the ore, the final product is cathode copper. The method is a heap leaching method like that of the copper method in that it utilises sulfuric acid instead of cyanide solution to dissolve the target minerals from crushed ore. There currently are no operating commercial scale nickel laterite heap leach operations, thus, a unique feature of nickel heap leaching is the need for a tailings disposal area. The final product can be nickel hydroxide precipitates or mixed metal hydroxide precipitates, similar to copper oxide heap leaching, also using dilute sulfuric acid. Rio Tinto is commercializing this technology in Namibia and Australia, the French nuclear power company Areva in Niger and Namibia, the final product is yellowcake and requires significant further processing to produce fuel-grade feed
Heap leach
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Gold heap leaching
Heap leach
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Left: ore fines without agglomeration. Right: Ore fines after agglomeration - Improved percolation as a result of agglomeration.
12.
Newmont Mining
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Holdings include Santa Fe Gold, Battle Mountain Gold, Normandy Mining, Franco-Nevada Corp and Fronteer Gold. Newmont also has joint venture relationships. As of the quarter of 2014, Newmont was the worlds second-largest producer of gold. In 2010 Newmont produced approximately 5.4 million equity ounces of gold annually, Newmont employs approximately 34,000 employees and contractors worldwide. Other metals that the mines include copper and silver. Newmont is the gold company in the Standard & Poors 500 Index. In 2016 Newmont produced 4.9 million ounces of gold, all-in sustaining costs totaled $912 per ounce of gold produced. Newmont Mining Corporation was founded in 1916 in New York by Colonel William Boyce Thompson as a company to invest in Worldwide mineral, oil. According to company lore, the name Newmont is a portmanteau New York and Montana, reflecting where Thompson made his fortune, in 1929, Newmont became a mining company with its first gold product in by acquiring Californias Empire Star Mine. By 1939, Newmont was operating 12 gold mines in North America, for decades around the middle of the 20th century, Newmont had a controlling interest in the Tsumeb mine in Namibia and in the OOkiep Copper Company in Namaqualand, South Africa. Beginning in 1925, Newmont acquired interests in a Texas oil field, eventually, Newmonts oil interests included more than 70 blocks in the Louisiana, Gulf of Mexico area and oil and gas production in the North Sea. Newmont discovered the worlds first submicroscopic or invisible gold at Carlin, Nevada in the early 1960s, the Carlin Trend or Carlin Unconformity is the largest gold discovery in North America during the 20th century. In 1971 Newmont began using the heap leaching technology on sub-mill grade ores there, after 1987, the company undertook major restructuring. This included the payment of a US$33 per share dividend to all shareholders for a total of US$2.2 billion, to reduce this debt the company undertook a divestment program involving all of its copper, oil, gas, and coal interests. As a further step in the restructuring, the company moved its headquarters from New York City to Denver in 1988, a decade later, Newmont Mining Corporation and Newmont Gold Company combined assets to form a unified worldwide gold company. Shareholders of both companies had identical interests in the reserves, production and earnings of Newmont Golds operations, Newmont then merged with Santa Fe Pacific Gold Corporation to form North Americas largest gold producer. On June 21,2000, Newmont announced a merger with Battle Mountain Gold Company, the merger was completed in January 2001. In February 2002, Newmont completed the acquisition of Normandy Mining Limited, Newmont faced competition in its bid for Normandy from AngloGold
Newmont Mining
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William Boyce Thompson, founder of Newmont Mining
Newmont Mining
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Newmont Mining Corporation
Newmont Mining
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Gold Quarry mine, near Carlin, Nevada, 2009.
Newmont Mining
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The Super Pit gold mine
13.
Carlin type gold deposit
–
Carlin–type gold deposits are sediment-hosted disseminated gold deposits. These deposits are characterized by gold in pyrite and arsenopyrite. This dissolved kind of gold is called Invisible Gold, as it can only be found through chemical analysis, the deposit is named after the Carlin mine, the first large deposit of this type discovered in the Carlin Trend, Nevada. The Carlin type deposits show enrichment in the gold, arsenic, antimony, mercury. This enrichment is created by hydrothermal circulation with a temperature of up to 300 °C, the underlying rocks out of which the minerals are dissolved are normally silty carbonates, although also silicates and other sediments are possible. The source of the heating for the water in the circulation is still under discussion. The material in the deposit is altered in a way that the minerals are either dissolved or converted to the silicates by silicate rich hydrothermal water. For example, dolomite is transformed into jasperoid, another alteration is the formation of clay minerals by interaction of water and feldspar. The absence of metal sulfides and the even distribution of the pyrite and arsenopyrite in the host rock are the most obvious difference to other sulfide deposits. The Carlin–type deposits represent some of the largest hydrothermal gold deposits in the world, the invisible nature of the gold in the deposit makes it difficult to find deposits of that kind. The class of deposit was defined after the Carlin mine became a producer of gold in the 1960s. Most of the mines in the Great Basin in the United States belong to the Carlin type, Carlin type deposits have also been found in China, Iran, and Macedonia. Gold mining in Nevada The Rush to Uncover Gold’s Origins, Geotimes, April 2006
Carlin type gold deposit
–
Goldstrike (Post–Betze) Mine, Carlin Trend, Nevada, the largest Carlin-type deposit in the world, containing more than 35,000,000 ounces gold.
Carlin type gold deposit
–
Sedimentary-rock hosted gold deposits in Nevada. All of the deposits shown that are north and east of the Battle Mountain-Eureka trend (and many of the others) are Carlin-type gold deposits. Source: USGS
Carlin type gold deposit
–
Carlin-type gold ore from the Twin Creeks mine, Nevada, near the Getchell Mine. This is an auriferous, silicified-decalcified siltstone/mudstone from the Comus Formation (Lower Ordovician). Ore grade is about 0.20 to 0.25 ounces of gold per ton of rock. The gold mineralization is very finely disseminated: "invisible gold".
14.
Epithermal
–
Hydrothermal circulation in its most general sense is the circulation of hot water. Hydrothermal circulation occurs most often in the vicinity of sources of heat within the Earths crust, in general, this occurs near volcanic activity, but can occur in the deep crust related to the intrusion of granite, or as the result of orogeny or metamorphism. Hydrothermal circulation in the oceans is the passage of the water through mid-oceanic ridge systems, the former circulation type is sometimes termed active, and the latter passive. The heat source for the active vents is the newly formed basalt, and, for the highest temperature vents, the heat source for the passive vents is the still-cooling older basalts. Heat flow studies of the seafloor suggest that basalts within the oceanic crust take millions of years to cool as they continue to support passive hydrothermal circulation systems. Hydrothermal vents are locations on the seafloor where hydrothermal fluids mix into the overlying ocean, perhaps the best-known vent forms are the naturally occurring chimneys referred to as black smokers. Hydrothermal circulation is not limited to ocean ridge environments, the source water for hydrothermal explosions, geysers, and hot springs is heated groundwater convecting below and lateral to the hot water vent. Hydrothermal circulating convection cells exist any place an anomalous source of heat, such as an intruding magma or volcanic vent, hydrothermal also refers to the transport and circulation of water within the deep crust, in general from areas of hot rocks to areas of cooler rocks. During the early 1900s, various geologists worked to classify hydrothermal ore deposits that they assumed formed from upward-flowing aqueous solutions, waldemar Lindgren developed a classification based on interpreted decreasing temperature and pressure conditions of the depositing fluid. His terms, hypothermal, mesothermal, epithermal and teleothermal, expressed decreasing temperature, recent studies retain only the epithermal label
Epithermal
–
Waves
15.
Carbonate rock
–
Carbonate rocks are a class of sedimentary rocks composed primarily of carbonate minerals. The two major types are limestone, which is composed of calcite or aragonite and dolostone, which is composed of the mineral dolomite. Calcite can be dissolved by groundwater or precipitated by groundwater, depending on several factors including the water temperature, pH. Calcite exhibits a characteristic called retrograde solubility in which it becomes less soluble in water as the temperature increases. When conditions are right for precipitation, calcite forms mineral coatings that cement the existing rock grains together or it can fill fractures, karst topography and caves develop in carbonate rocks because of their solubility in dilute acidic groundwater. Cooling groundwater or mixing of different groundwaters will also create conditions suitable for cave formation, marble is the metamorphic carbonate rock. Rare igneous carbonate rocks exist as intrusive carbonatites and even rarer volcanic carbonate lava
Carbonate rock
–
Carbonate ooids on the surface of a limestone; Carmel Formation (Middle Jurassic) of southern Utah, USA. Largest is 1.0 mm in diameter.
16.
Silicate
–
A silicate is a compound containing an anionic silicon compound. The great majority of the silicates are oxides, but hexafluorosilicate, orthosilicate is the anion SiO4−4 or its compounds. Related to orthosilicate are families of anions with the formula 2n−, important members are the cyclic and single chain silicates n and the sheet-forming silicates n. Silicates constitute the majority of Earths crust, as well as the terrestrial planets, rocky moons. Sand, Portland cement, and thousands of minerals are examples of silicates, silicate compounds, including the minerals, consist of silicate anions whose charge is balanced by various cations. Myriad silicate anions can exist, and each can form compounds with many different cations, hence this class of compounds is very large. Both minerals and synthetic materials fit in this class, in the vast majority of silicates, including silicate minerals, the Si occupies a tetrahedral environment, being surrounded by 4 oxygen centres. In these structures, the bonds to silicon conform to the octet rule. These tetrahedra sometimes occur as isolated SiO4−4 centres, but most commonly, commonly the silicate anions are chains, double chains, sheets, and three-dimensional frameworks. All these such species have negligible solubility in water at normal conditions, silicates are well characterized as solids, but are less commonly observed in solution. The anion SiO4−4 is the base of silicic acid, Si4. Instead, solutions of silicates are usually observed as mixtures of condensed, the nature of soluble silicates is relevant to understanding biomineralization and the synthesis of aluminosilicates, such as the industrially important catalysts called zeolites. Although the tetrahedron is the coordination geometry for silicon compounds. A well-known example of such a high number is hexafluorosilicate. Octahedral coordination by 6 oxygen centres is observed, at very high pressure, even SiO2 adopts this geometry in the mineral stishovite, a dense polymorph of silica found in the lower mantle of the Earth. This structure is formed by shock during meteorite impacts. In geology and astronomy, the silicate is used to denote types of rock that consist predominantly of silicate minerals. On Earth, a variety of silicate minerals occur in an even wider range of combinations as a result of the processes that form
Silicate
–
Diatomaceous earth, as viewed under a microscope, is a soft, siliceous, sedimentary rock made up of the frustules (shells) of single cell diatoms. Diatom cell walls are made up of biogenic silica; silica synthesised in the diatom cell by the polymerisation of silicic acid. This image of diatomaceous earth particles in water is at a scale of 6.236 pixels/ μm, the entire image covers a region of approximately 1.13 by 0.69 mm.
Silicate
–
Basic (ortho-)silicate oxoanion (SiO 4 −4) structure
17.
Sedimentary rock
–
Sedimentary rocks are types of rock that are formed by the deposition and subsequent cementation of that material at the Earths surface and within bodies of water. Sedimentation is the name for processes that cause mineral and/or organic particles to settle in place. The particles that form a rock by accumulating are called sediment. Sedimentation may also occur as minerals precipitate from solution or shells of aquatic creatures settle out of suspension. The sedimentary rock cover of the continents of the Earths crust is extensive, sedimentary rocks are only a thin veneer over a crust consisting mainly of igneous and metamorphic rocks. Sedimentary rocks are deposited in layers as strata, forming a structure called bedding, sedimentary rocks are also important sources of natural resources like coal, fossil fuels, drinking water or ores. The study of the sequence of rock strata is the main source for an understanding of the Earths history, including palaeogeography, paleoclimatology. The scientific discipline that studies the properties and origin of rocks is called sedimentology. Sedimentology is part of both geology and physical geography and overlaps partly with other disciplines in the Earth sciences, such as pedology, geomorphology, geochemistry, sedimentary rocks have also been found on Mars. Clastic sedimentary rocks are composed of rock fragments that were cemented by silicate minerals. Clastic rocks are composed largely of quartz, feldspar, rock fragments, clay minerals, and mica, any type of mineral may be present, clastic sedimentary rocks, are subdivided according to the dominant particle size. Most geologists use the Udden-Wentworth grain size scale and divide unconsolidated sediment into three fractions, gravel, sand, and mud and this tripartite subdivision is mirrored by the broad categories of rudites, arenites, and lutites, respectively, in older literature. The subdivision of these three categories is based on differences in clast shape, conglomerates and breccias), composition. Conglomerates are dominantly composed of rounded gravel, while breccias are composed of dominantly angular gravel, composition of framework grains The relative abundance of sand-sized framework grains determines the first word in a sandstone name. Naming depends on the dominance of the three most abundant components quartz, feldspar, or the lithic fragments that originated from other rocks, all other minerals are considered accessories and not used in the naming of the rock, regardless of abundance. Clean sandstones with open space are called arenites. Muddy sandstones with abundant muddy matrix are called wackes, six sandstone names are possible using the descriptors for grain composition and the amount of matrix. Mudrocks are sedimentary rocks composed of at least 50% silt- and clay-sized particles and these relatively fine-grained particles are commonly transported by turbulent flow in water or air, and deposited as the flow calms and the particles settle out of suspension
Sedimentary rock
–
Middle Triassic marginal marine sequence of siltstones (reddish layers at the cliff base) and limestones (brown rocks above), Virgin Formation, southwestern Utah, USA
Sedimentary rock
–
Sedimentary rocks on Mars, investigated by NASA's Curiosity Mars rover
Sedimentary rock
–
Steeply dipping sedimentary rock strata along the Chalous Road in northern Iran
Sedimentary rock
–
Claystone deposited in Glacial Lake Missoula, Montana, United States. Note the very fine and flat bedding, common for distal lacustrine deposition.
18.
Magmatic
–
Besides molten rock, magma may also contain suspended crystals, dissolved gas and sometimes gas bubbles. Magma often collects in magma chambers that may feed a volcano or solidify underground to form an intrusion, magma is capable of intruding into adjacent rocks, extrusion onto the surface as lava, and explosive ejection as tephra to form pyroclastic rock. Magma is a complex high-temperature fluid substance, temperatures of most magmas are in the range 700 °C to 1300 °C, but very rare carbonatite magmas may be as cool as 600 °C, and komatiite magmas may have been as hot as 1600 °C. Environments of magma formation and compositions are commonly correlated, environments include subduction zones, continental rift zones, mid-ocean ridges and hotspots. Despite being found in such locales, the bulk of the Earths crust. Except for the outer core, most of the Earth takes the form of a rheid. Magma, as liquid, preferentially forms in high temperature, low pressure environments within several kilometers of the Earths surface, magma compositions may evolve after formation by fractional crystallization, contamination, and magma mixing. By definition rock formed of solidified magma is called igneous rock, melting of solid rocks to form magma is controlled by three physical parameters, temperature, pressure, and composition. Mechanisms are discussed in the entry for igneous rock, as a rock melts, its volume changes. When enough rock is melted, the small globules of melt link up, under pressure within the earth, as little as a fraction of a percent partial melting may be sufficient to cause melt to be squeezed from its source. The degree of melting is critical for determining what type of magma is produced. The degree of partial melting required to form a melt can be estimated by considering the relative enrichment of incompatible elements versus compatible elements, incompatible elements commonly include potassium, barium, cesium, and rubidium. Rock types produced by small degrees of melting in the Earths mantle are typically alkaline. Typically, primitive melts of this composition form lamprophyre, lamproite, kimberlite and sometimes nepheline-bearing mafic rocks such as alkali basalts, pegmatite may be produced by low degrees of partial melting of the crust. Some granite-composition magmas are eutectic melts, and they may be produced by low to high degrees of melting of the crust. At high degrees of melting of the crust, granitoids such as tonalite, granodiorite and monzonite can be produced. Being only the time in recorded history that magma had been reached, IDDP decided to invest in the hole. A cemented steel case was constructed in the hole with a perforation at the close to the magma
Magmatic
–
Lava flow on Hawaii. Lava is the extrusive equivalent of magma.
19.
Open-pit mining
–
Open-pit, open-cast or open cut mining is a surface mining technique of extracting rock or minerals from the earth by their removal from an open pit or borrow. This form of mining differs from extractive methods that require tunneling into the earth, for minerals that occur deep below the surface—where the overburden is thick or the mineral occurs as veins in hard rock—underground mining methods are used to extract the valued material. Open-pit mines that produce building materials and dimension stone are commonly referred to as quarries, open-pit mines are typically enlarged until either the mineral resource is exhausted, or an increasing ratio of overburden to ore makes further mining uneconomic. When this occurs, the mines are sometimes converted to landfills for disposal of solid wastes. Open-cast mines are dug on benches, which describe vertical levels of the hole and these benches are usually on four to sixty meter intervals, depending on the size of the machinery that is being used. Many quarries do not use benches, as they are usually shallow, most walls of the pit are generally blast mined on an angle less than vertical, to prevent and minimize damage and danger from rock falls. This depends on how weathered the rocks are, and the type of rock, the inclined section of the wall is known as the batter, and the flat part of the step is known as the bench or berm. The steps in the walls help prevent rock falls continuing down the face of the wall. In some instances additional ground support is required and rock bolts, cable bolts, de-watering bores may be used to relieve water pressure by drilling horizontally into the wall, which is often enough to cause failures in the wall by itself. A haul road is situated at the side of the pit, forming a ramp up which trucks can drive, carrying ore. Waste rock is piled up at the surface, near the edge of the open pit and this is known as the waste dump. The waste dump is also tiered and stepped, to minimize degradation, ore which has been processed is known as tailings, and is generally a slurry. This is pumped to a dam or settling pond, where the water evaporates. This toxicity can harm the surrounding environment, after mining finishes, the mine area may undergo land rehabilitation. Waste dumps are contoured to flatten out, to further stabilise them. This is then covered with soil, and vegetation is planted to help consolidate the material. There are no long term studies on the success of these due to the relatively short time in which large scale open pit mining has existed. It may take hundreds to thousands of years for some waste dumps to become acid neutral, the dumps are usually fenced off to prevent livestock denuding them of vegetation
Open-pit mining
–
Rock blasting at the large open-pit Twin Creeks gold mine in Nevada, United States. Note the size of the excavators for scale (foreground, left), and that the bottom of the mine is not visible.
Open-pit mining
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Note the angled and stepped sides of the Sunrise Dam Gold Mine, Australia.
Open-pit mining
–
The Klunst rock quarry in Saxony, Germany, has few benches.
Open-pit mining
–
An open-pit sulfur mine at Tarnobrzeg, Poland undergoing land rehabilitation
20.
Underground mining (hard rock)
–
Soft rock mining refers to excavation of softer minerals such as salt, coal, or oil sands. Accessing underground ore can be achieved via a decline, inclined vertical shaft or adit, declines can be a spiral tunnel which circles either the flank of the deposit or circles around the deposit. The decline begins with a box cut, which is the portal to the surface, depending on the amount of overburden and quality of bedrock, a galvanized steel culvert may be required for safety purposes. They may also be started into the wall of an open cut mine, shafts are vertical excavations sunk adjacent to an ore body. Shafts are sunk for ore bodies where haulage to surface via truck is not economical, Shaft haulage is more economical than truck haulage at depth, and a mine may have both a decline and a ramp. Adits are horizontal excavations into the side of a hill or mountain and they are used for horizontal or near-horizontal ore bodies where there is no need for a ramp or shaft. They are also built and maintained as an emergency safety access from the underground workings. Levels are excavated horizontally off the decline or shaft to access the ore body, stopes are then excavated perpendicular to the level into the ore. There are two phases of underground mining, development mining and production mining. Development mining is composed of excavation almost entirely in waste rock in order to access to the orebody. To start the mining first step is to make the path to go down, the path is defined as Decline as describe above. Before the start of Decline all preplanning of Power facility, drilling arrangement, dewatering, ventilation and, production mining is further broken down into two methods, long hole and short hole. Short hole mining is similar to development mining, except that it occurs in ore, there are several different methods of long hole mining. Typically long hole mining requires two excavations within the ore at different elevations below surface, holes are drilled between the two excavations and loaded with explosives. The holes are blasted and the ore is removed from the bottom excavation, one of the most important aspects of underground hard rock mining is ventilation. Ventilation is also used to manage underground temperatures for the workers, in deep, hot mines ventilation is used to cool the workplace, however, in very cold locations the air is heated to just above freezing before it enters the mine. Ventilation raises are typically used to transfer ventilation from surface to the workplaces, the primary sources of heat in underground hard rock mines are virgin rock temperature, machinery, auto compression, and fissure water. Other small contributing factors are human body heat and blasting, some means of support is required in order to maintain the stability of the openings that are excavated
Underground mining (hard rock)
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A three-dimensional model of an underground mine with shaft access
Underground mining (hard rock)
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Decline portal at Wiluna Gold Mine
Underground mining (hard rock)
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Door for directing ventilation in an old lead mine. The ore hopper at the front is not part of the ventilation.
21.
Gold cyanidation
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Gold cyanidation is a metallurgical technique for extracting gold from low-grade ore by converting the gold to a water-soluble coordination complex. It is the most commonly used process for gold extraction, due to the highly poisonous nature of cyanide, the process is controversial and its usage is banned in a number of countries and territories. In 1783, Carl Wilhelm Scheele discovered that dissolved in aqueous solutions of cyanide. Through the work of Bagration, Elsner, and Faraday, it was determined that each atom of gold required two cyanide ions, i. e. the stoichiometry of the soluble compound. The expansion of mining in the Rand of South Africa began to slow down in the 1880s. The gold could not be extracted from this compound with any of the available chemical processes or technologies. By suspending the crushed ore in a solution, a separation of up to 96 percent pure gold was achieved. The process was first used on the Rand in 1890 and, despite operational imperfections, in 1896, Bodländer confirmed that oxygen was necessary for the process, something that had been doubted by MacArthur, and discovered that hydrogen peroxide was formed as an intermediate. The ore is comminuted using grinding machinery, depending on the ore, it is sometimes further concentrated by froth flotation or by centrifugal concentration. Water is added to produce a slurry or pulp, the basic ore slurry can be combined with a solution of sodium cyanide or potassium cyanide, however many operations utilize calcium cyanide, which is more cost effective. Lead nitrate can improve gold leaching speed and quantity recovered, particularly in processing partially oxidized ores, oxygen is one of the reagents consumed during cyanidation, and a deficiency in dissolved oxygen slows leaching rate. Air or pure oxygen gas can be purged through the pulp to maximize the oxygen concentration. Oxygen can also be added by dosing the pulp with hydrogen peroxide solution, specifically, the oxidation of iron to iron oxide and subsequent precipitation as iron hydroxide minimizes loss of cyanide from the formation of ferrous cyanide complexes. The oxidation of sulfur compounds to sulfate ions avoids the consumption of cyanide to thiocyanate byproduct and this reduces the concentrations of these cyanide compounds, but does not completely eliminate them from the stream. The two major processes utilised are the INCO-licensed process or the Caros acid process, hydrogen peroxide and basic chlorination can also be used, although these are typically less common. One of the alternative oxidants for the degradation of cyanides that has been attracting industrial interest is Caros acid – peroxomonosulphuric acid, Caros acid converts cyanide to cyanate. Cyanate then hydrolyses in the water to ammonium and carbonate ions, the Caros acid process is able to achieve discharge levels of WAD below 50 mg/L, which is generally suitable for discharge to tailings. Over 90 mines worldwide now use an Inco SO2/air detoxification circuit to convert cyanide to the less toxic cyanate before waste is discharged to a tailings pond
Gold cyanidation
–
John Stewart MacArthur developed the cyanide process for gold extraction in 1887.
Gold cyanidation
Gold cyanidation
–
Cyanide leaching "heap" at a gold mining operation near Elko, Nevada
Gold cyanidation
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Sodium cyanide drum at the abandoned Chemung Mine in Masonic, California
22.
Thiosulfate
–
Thiosulfate is an oxyanion of sulfur. The prefix thio- indicates that the ion is a sulfate ion with one oxygen replaced by sulfur. Thiosulfate has a molecular shape with C3v symmetry. Thiosulfate occurs naturally and is produced by certain biochemical processes and it rapidly dechlorinates water and is notable for its use to halt bleaching in the paper-making industry. Thiosulfate is also useful in smelting silver ore, in producing leather goods, if white light is shone from below, blue light is seen from sideways and orange from above, due to the same mechanisms that color the sky at mid-day and dusk. Addition of molybdenum to stainless steel is needed to improve its resistance to pitting, in alkaline aqueous conditions and medium temperature, carbon steel and stainless steel are not attacked, even at high concentration of base, thiosulfate and in presence of fluoride ion. The natural occurrence of the group is practically restricted to a very rare mineral sidpietersite, Pb4O22. Thiosulfate extensively forms complexes with transition metals hence a common use is dissolving silver halides in film photography developing, Thiosulfate is also used to extract or leach gold and silver from their ores as a less toxic alternative to cyanide. The systematic additive IUPAC name is trioxido-1κ3O-disulfate, the name of its acid is dihydroxido-1κ2O-oxido-1κ1O-disulfur. The external sulfur has a state of while the central sulfur atom has oxidation number as. The enzyme rhodanase catalyzes the detoxification of cyanide by thiosulfate, CN− + S 2O2−3 → SCN− + SO2−3, sodium thiosulfate has been considered as an empirical treatment for cyanide poisoning, along with hydroxocobalamin. TST is associated with protection against obesity and type II diabetes, tetrathionate Thiosulfuric acid Thiosulfate ion General Chemistry Online, Frostburg State University
Thiosulfate
–
The structure of the thiosulfate anion
23.
Bullion
–
Bullion is gold bars, silver bars, and other bars or ingots of precious metal. The word bullion comes from the French Minister of Finance under Louis XIII, the value of bullion is typically determined by the value of its precious metals content, which is defined by its purity and mass. It is also weighed extremely accurately, retailers may sometimes market ingots and bars of base metals, such as copper, nickel, and aluminium as bullion, but this is not a widely accepted definition. The specifications of bullion are often regulated by market bodies or legislation, in the European Union, the minimum purity for gold bullion, which is treated as investment gold with regards to taxation, is 99. 5% for gold bullion bars and 90% for bullion coins. The London bullion market is a market for wholesale trading of gold. The London Bullion Market Association coordinates activities of its members and other participants in the London bullion market, the LBMA sets and promotes quality standards for gold and silver bullion bars. The minimum acceptable fineness of the Good Delivery Bars is 99. 5% for gold bars and 99. 9% for silver bars, Bullion coins describe contemporary precious metal coins minted by official agencies for investment purposes. Historically, most currency were in the form of coins, silver. Some bullion coins have been used as currency throughout the 20th century, like the Maria Theresa thaler, however, modern bullion coins generally do not enter common circulation despite having legal tender status and a nominal face value. Some modern bullion coins, such as the gold and silver American eagle, are produced as both business strike and collectible proof and uncirculated versions. Business strikes typically are sold at prices commensurate with their precious metal content, in some cases the grade and mintages of business strike coins can affect their value, so that they are considered numismatic rather than bullion items. A range of market participants is active in the bullion markets, banks, fabricators, refiners. They provide facilities for the refining, melting, assaying, transporting, trading and vaulting of gold, for example, shares of the world’s largest Gold exchange-traded fund, the SPDR Gold Shares represent ownership in vaulted gold bullion. Private individuals use bullion primarily as an investment or potential store of value, Gold bullion and silver bullion are the most important forms of physical precious metals investments. Bullion investments can be considered as insurance against inflation or economic turmoil, compared to numismatic coins, bullion bars or bullion coins can typically be purchased and traded at lower margins and their trading prices are closer to the values of the contained precious metals
Bullion
–
Gold bars, the typical form of bullion
24.
Flickr
–
Flickr is an image hosting and video hosting website and web services suite that was created by Ludicorp in 2004 and acquired by Yahoo on March 20,2005. The Verge reported in March 2013 that Flickr had a total of 87 million registered members, in August 2011 the site reported that it was hosting more than 6 billion images and this number continues to grow steadily according to reporting sources. Photos and videos can be accessed from Flickr without the need to register an account, registering an account also allows users to create a profile page containing photos and videos that the user has uploaded and also grants the ability to add another Flickr user as a contact. For mobile users, Flickr has official mobile apps for iOS, Android, and PlayStation Vita, operating systems, Flickr was launched in February 2004 by Ludicorp, a Vancouver-based company founded by Stewart Butterfield and Caterina Fake. The service emerged from tools originally created for Ludicorps Game Neverending, Flickr proved a more feasible project, and ultimately Game Neverending was shelved, Butterfield later launched a similar online game, Glitch, which closed down in November 2012. Early versions of Flickr focused on a room called FlickrLive with real-time photo exchange capabilities. The successive evolutions focused more on the uploading and filing backend for individual users and it was eventually dropped as Flickrs backend systems evolved away from Game Neverendings codebase. Key features of Flickr not initially present are tags, marking photos as favorites, group photo pools and interestingness, Yahoo acquired Ludicorp and Flickr in March 2005. The acquisition reportedly cost $22 to $25 million, during the week of 26 June –2 July 2005, all content was migrated from servers in Canada to servers in the United States, and all resulting data become subject to United States federal law. In May 2007, Yahoo announced that Yahoo Photos would close down on 20 September 2007, after which all photos would be deleted and this move was criticized by some users. Flickr upgraded its services from beta to gamma in May 2006, in December 2006, upload limits on free accounts were increased to 100 MB a month and were removed from Flickr Pro accounts, which originally had a 2 GB per month limit. On 9 April 2008, Flickr began allowing paid subscribers to upload videos, on 2 March 2009, Flickr added the facility to upload and view HD videos, and began allowing free users to upload normal-resolution video. At the same time, the set limit for free accounts was lifted, in 2009, Flickr announced a partnership with Getty Images in which selected users could submit photographs for stock photography usage and receive payment. In 2010, this was changed so that users could label images as suitable for stock use themselves, the Justified View is paginated between 72 and 360 photos per page but unpaginated in search result presentation. Tech Radar described the new style Flickr as representing a sea change in its purpose, many users criticized the changes, and the sites help forum received thousands of negative comments. In March 2014, Flickrs New Photo Experience, a user interface redesign, on May 7,2015, Yahoo overhauled the site, adding a revamped Camera Roll, a new way to upload photos and upgraded the sites apps. The new Uploadr application was available for Macs, Windows. In June 2008, Flickr co-founder Stewart Butterfield announced his resignation, which followed his wife and co-founder Caterina Fake, Butterfield wrote a humorous resignation letter to Brad Garlinghouse
Flickr
–
Typical Flickr album sets
Flickr
25.
Corporation
–
A corporation is a company or group of people authorized to act as a single entity and recognized as such in law. Early incorporated entities were established by charter, most jurisdictions now allow the creation of new corporations through registration. Corporations chartered in regions where they are distinguished by whether they are allowed to be for profit or not are referred to as for profit and not-for-profit corporations, there is some overlap between stock/non-stock and for profit/not-for-profit in that not-for-profit corporations are always non-stock as well. A for profit corporation is almost always a stock corporation, registered corporations have legal personality and are owned by shareholders whose liability is limited to their investment. Shareholders do not typically actively manage a corporation, shareholders instead elect or appoint a board of directors to control the corporation in a fiduciary capacity, in American English, the word corporation is most often used to describe large business corporations. In British English and in the Commonwealth countries, the company is more widely used to describe the same sort of entity while the word corporation encompasses all incorporated entities. In American English, the company can include entities such as partnerships that would not be referred to as companies in British English as they are not a separate legal entity. Despite not being human beings, corporations, as far as the law is concerned, are legal persons. Corporations can exercise human rights against real individuals and the state, Corporations can be dissolved either by statutory operation, order of court, or voluntary action on the part of shareholders. Corporations can even be convicted of offenses, such as fraud. However, corporations are not considered living entities in the way humans are. While not a corporation, this new type of entity became very attractive as an alternative for corporations not needing to issue stock, in Germany, the organization was referred to as Gesellschaft mit beschränkter Haftung or GmbH. In the last quarter of the 20th Century this new form of organization became available in the United States and other countries. Since the GmbH and LLC forms of organization are technically not corporations they will not be discussed in this article, the word corporation derives from corpus, the Latin word for body, or a body of people. By the time of Justinian, Roman law recognized a range of corporate entities under the names universitas and these included the state itself, municipalities, and such private associations as sponsors of a religious cult, burial clubs, political groups, and guilds of craftsmen or traders. Such bodies commonly had the right to own property and make contracts, to receive gifts and legacies, to sue and be sued, private associations were granted designated privileges and liberties by the emperor. Entities which carried on business and were the subjects of rights were found in ancient Rome. In medieval Europe, churches became incorporated, as did local governments, such as the Pope, the point was that the incorporation would survive longer than the lives of any particular member, existing in perpetuity
Corporation
–
McDonald's Corporation is one of the most recognizable corporations in the world.
Corporation
Corporation
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1/8 share of the Stora Kopparberg mine, dated June 16, 1288.
Corporation
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A bond issued by the Dutch East India Company, dating from 1623, for the amount of 2,400 florins
26.
Management
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Management is the administration of an organization, whether it be a business, a not-for-profit organization, or government body. The term management may also refer to the people who manage an organization, management is also an academic discipline, a social science whose objective is to study social organization and organizational leadership. Individuals who aim at becoming management researchers or professors may complete the Doctor of Business Administration or the PhD in business administration or management, in larger organizations, there are generally three levels of managers, which are typically organized in a hierarchical, pyramid structure. Senior managers provide direction to the managers who report to them. Middle managers, examples of which would include branch managers, regional managers and section managers, middle managers communicate the strategic goals of senior management to the front-line managers. Lower managers, such as supervisors and front-line team leaders, oversee the work of regular employees, in smaller organizations, the roles of managers have much wider scopes. A manager can perform several roles or even all of the commonly observed in a large organization. There are many smaller organizations than larger ones. Views on the definition and scope of management include, According to Henri Fayol, to manage is to forecast and to plan, to organise, to command, to co-ordinate, fredmund Malik defines it as the transformation of resources into utility. Management included as one of the factors of production - along with machines, materials, peter Drucker saw the basic task of management as twofold, marketing and innovation. Nevertheless, innovation is also linked to marketing, peter Drucker identifies marketing as a key essence for business success, but management and marketing are generally understood as two different branches of business administration knowledge. Management involves identifying the mission, objective, procedures, rules and this implies effective communication, an enterprise environment implies human motivation and implies some sort of successful progress or system outcome. As such, management is not the manipulation of a mechanism, not the herding of animals, management does not need to be seen from enterprise point of view alone, because management is an essential function to improve ones life and relationships. Management is therefore everywhere and it has a range of application. Based on this, management must have humans, communication, plans, measurements, motivational psychological tools, goals, and economic measures may or may not be necessary components for there to be management. At first, one views management functionally, such as measuring quantity, adjusting plans and this applies even in situations where planning does not take place. Critics, however, find this definition useful but far too narrow, one habit of thought regards management as equivalent to business administration and thus excludes management in places outside commerce, as for example in charities and in the public sector. More broadly, every organization must manage its work, people, processes, technology, nonetheless, many people refer to university departments that teach management as business schools
Management
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Business administration
27.
Chairman
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The chairman is the highest officer of an organized group such as a board, a committee, or a deliberative assembly. The person holding the office is elected or appointed by the members of the group. The chair presides over meetings of the group and conducts its business in an orderly fashion. When the group is not in session, the officers duties include acting as its head, its representative to the outside world. In some organizations, this position is called president, in others, where a board appoints a president. Other terms sometimes used for the office and its holder include chair, chairperson, chairwoman, presiding officer, president, moderator, facilitator, the chairman of a parliamentary chamber is often called the speaker. The term chair is used in lieu of chairman, in response to criticisms that using chairman is sexist. In his 1992 State of the Union address, then-U. S, president George H. W. Bush used chairman for men and chair for women. A1994 Canadian study found the Toronto Star newspaper referring to most presiding men as chairman, the Chronicle of Higher Education uses chairman for men and chairperson for women. An analysis of the British National Corpus found chairman used 1,142 times, chairperson 130 times, the National Association of Parliamentarians does not approve using chairperson. In World Schools Style debating, male chairs are called Mr. Chairman, the FranklinCovey Style Guide for Business and Technical Communication, as well as the American Psychological Association style guide, advocate using chair or chairperson, rather than chairman. The Oxford Dictionary of American Usage and Style suggests that the forms are gaining ground. It advocates using chair to refer both to men and to women, the word chair can refer to the place from which the holder of the office presides, whether on a chair, at a lectern, or elsewhere. During meetings, the person presiding is said to be in the chair and is referred to as the chair. Major dictionaries state that the word derives from chair and man, some authorities, however, including Riddicks Rules of Procedure, suggest that the second part of chairman derives from the Latin manus, and thus claim gender-neutrality for the word. Vladimir Lenin, for example, officially functioned as the head of Soviet Russia not as tsar or as president, note in particular the popular standard method for referring to Mao Zedong, Chairman Mao. In the absence of the chairman and vice chairman, groups sometimes elect a chairman pro tempore to fill the role for a single meeting. In some organizations that have titles, deputy chairman ranks higher than vice chairman, as there are often multiple vice chairs
Chairman
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Chairman of a Swedish and American society of relatives of over 5000 members, in Stockholm in 2015 with the society's banner flying
28.
Board of directors
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A board of directors is a body of elected or appointed members who jointly oversee the activities of a corporation or organization, which can include a non-profit organization or a government agency. A board of directors activities are determined by the powers, duties and responsibilities conferred on it by an authority outside itself and these matters are typically detailed in regulations or in the organizations constitution and bylaws. These authorities may specify the number of members of the board, how they are to be chosen, and how often they are to meet. In an organization with voting members, the board is accountable to, and might be subordinate to, the full membership. In a stock corporation, non-executive directors are voted for by the shareholders, the board of directors appoints the chief executive officer of the corporation and sets out the overall strategic direction. In corporations with dispersed ownership, the identification and nomination of directors are often done by the board itself, in a non-stock corporation with no general voting membership, the board is the supreme governing body of the institution, its members are sometimes chosen by the board itself. Other names include Board of directors and advisors, board of governors, board of managers, board of regents, board of trustees and it may also be called the executive board and is often simply referred to as the board. For companies with publicly trading stock, these responsibilities are typically much more rigorous, typically, the board chooses one of its members to be the chairman, who holds whatever title is specified in the bylaws or articles of association. However, in organizations, the members elect the president of the organization. The directors of an organization are the persons who are members of its board, several specific terms categorize directors by the presence or absence of their other relationships to the organization. An inside director is a director who is also an employee, officer, chief executive, major shareholder, inside directors represent the interests of the entitys stakeholders, and often have special knowledge of its inner workings, its financial or market position, and so on. Executive directors often have an area of responsibility in the organization, such as finance, marketing, human resources. An outside director is a member of the board who is not otherwise employed by or engaged with the organization, a typical example is a director who is president of a firm in a different industry. Outside directors are not employees of the company or affiliated with it in any other way, outside directors bring outside experience and perspectives to the board. One of the arguments for having outside directors is that they can keep a eye on the inside directors. Outside directors are unlikely to tolerate insider dealing between insider directors, as outside directors do not benefit from the company or organization, outside directors are often useful in handling disputes between inside directors, or between shareholders and the board. They are thought to be advantageous because they can be objective, director - a person appointed to serve on the board of an organization, such as an institution or business. This practice results in an interlocking directorate, where a small number of individuals have significant influence over a large number of important entities
Board of directors
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A meeting of a board of directors of the Leipzig–Dresden Railway Company in 1852
29.
Dambisa Moyo
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Dambisa Moyo is a Zambian-born international economist and author who analyzes the macroeconomy and global affairs. She currently serves on the boards of Barclays Bank, the financial group, SABMiller, the global brewer, and Barrick Gold. She worked for two years at the World Bank and eight years at Goldman Sachs before becoming an author and she holds a Bachelors degree in Chemistry and MBA from American University, an MPA from the Harvard Kennedy School, and a DPhil in Economics from Oxford. Dambisa Moyo was born in 1969 in Lusaka, the capital of Zambia and she finished her degree in the U. S. via a scholarship to American University in Washington, D. C. Moyo received a BS in Chemistry from American University in 1991, and she acquired a Master of Public Administration degree at Harvard Universitys John F. Kennedy School of Government in 1997. In 2002 she received a DPhil in Economics from St Antonys College and her Oxford studies were in macroeconomics, and her doctoral dissertation was on savings rates in developing countries. Following her MBA from American University, Moyo worked at the World Bank from May 1993 to September 1995 and she was a consultant in the Europe and Central Asia department and the Africa department, and co-authored the World Banks annual World Development Report. After pursuing her MPA and PhD degrees at Harvard and Oxford and she was at the company until November 2008, working mainly in debt capital markets, hedge funds coverage, and global macroeconomics. Part of her tenure at Goldman Sachs was spent advising developing countries on the issuing of bonds on the international market and she was also Head of Economic Research and Strategy for Sub–Saharan Africa. After leaving Goldman Sachs, Moyo joined the board of directors of the international brewer SABMiller in 2009, in 2010 Moyo joined the board of directors of Barclays Bank. She sits on three of the committees, the Audit Committee, the Conduct, Operational and Reputational Risk Committee. In 2011 she joined the board of directors of the mining company Barrick Gold. She sits on the boards Audit Committee, Corporate Governance and Nomination Committee, in 2015 Moyo joined the board of directors of data storage company Seagate Technology. On August 9,2016, Chevron Corporation announced that Dr. Dambisa Moyo, according to the Press Release, Dr. Moyo’s appointment would be effective October 11,2016. Moyo is a board member of the charity Lundin for Africa. She is also a board member of Room to Read. Moyos first book, Dead Aid, Why Aid Is Not Working, Dead Aid catapulted Moyo into the public eye and made her a sought-after speaker, pundit, and author. In 2009 she was named a World Economic Forum Young Global Leader, one of TIMEs 100, the book consolidated her career of traveling worldwide investigating and analyzing economic conditions and writing about her conclusions
Dambisa Moyo
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Dambisa Moyo
30.
Mining
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Mining is extraction of valuable minerals or other geological materials from the earth usually from an orebody, lode, vein, seam, reef or placer deposits. These deposits form a mineralized package that is of economic interest to the miner, ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain any material that cannot be grown through agricultural processes, Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Mining of stones and metal has been a human activity since pre-historic times, Mining operations usually create a negative environmental impact, both during the mining activity and after the mine has closed. Hence, most of the nations have passed regulations to decrease the impact. Work safety has long been a concern as well, and modern practices have significantly improved safety in mines, levels of metals recycling are generally low. Unless future end-of-life recycling rates are stepped up, some rare metals may become unavailable for use in a variety of consumer products, due to the low recycling rates, some landfills now contain higher concentrations of metal than mines themselves. Since the beginning of civilization, people have used stone, ceramics and, later and these were used to make early tools and weapons, for example, high quality flint found in northern France, southern England and Poland was used to create flint tools. Flint mines have been found in areas where seams of the stone were followed underground by shafts. The mines at Grimes Graves and Krzemionki are especially famous, other hard rocks mined or collected for axes included the greenstone of the Langdale axe industry based in the English Lake District. The oldest-known mine on archaeological record is the Lion Cave in Swaziland, at this site Paleolithic humans mined hematite to make the red pigment ochre. Mines of an age in Hungary are believed to be sites where Neanderthals may have mined flint for weapons. Ancient Egyptians mined malachite at Maadi, at first, Egyptians used the bright green malachite stones for ornamentations and pottery. Later, between 2613 and 2494 BC, large building projects required expeditions abroad to the area of Wadi Maghareh in order to secure minerals and other resources not available in Egypt itself. Quarries for turquoise and copper were found at Wadi Hammamat, Tura, Aswan and various other Nubian sites on the Sinai Peninsula. Mining in Egypt occurred in the earliest dynasties, the gold mines of Nubia were among the largest and most extensive of any in Ancient Egypt. These mines are described by the Greek author Diodorus Siculus, who mentions fire-setting as one used to break down the hard rock holding the gold. One of the complexes is shown in one of the earliest known maps, the miners crushed the ore and ground it to a fine powder before washing the powder for the gold dust
Mining
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Surface coal mining
Mining
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Chalcolithic copper mine in Timna Valley, Negev Desert
Mining
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Ancient Roman development of the Dolaucothi Gold Mines, Wales
Mining
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Agricola, author of De Re Metallica
31.
Cortez Gold Mine
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Cortez Gold Mine is a large gold mining and processing facility in Lander and Eureka County, Nevada, United States, located approximately 75 miles southwest of Elko. It is owned and operated by Barrick Gold and comprises the Pipeline and South Pipeline deposits, Pipeline and South Pipeline are open pit mines, while Cortez Hills is an underground and open pit mining operation. Under continuous operation, Cortez has been longer than any gold mine in the state of Nevada. It is Barricks and Nevadas largest gold producer, the Cortez Mountains has been mined since 1862, with silver being the primary commodity until the 1940s. The Gold Acres operation in the Cortez Mountains included open pit, Cortez Gold opened in 1968 and production ended in 1976. The United States Bureau of Mines built a plant in 1969 which would make heap leaching for gold in commercially viable by 1971. The low grade ore and dump material from the Gold Acres operation was then heap leached, the Cortez mill was reopened as the price of gold increased in the early 1980s, feed for the mill was provided by the nearby Horse Canyon deposit between 1983 and 1987. Further exploration of the region was carried out by Cortez Joint Venture which involved Placer Dome, the result of the joint ventures exploration was the 1991 discovery of the Pipeline orebody. The Pipeline orebody was located near the Gold Acres operation, instead of being located in the foothills, the Pipeline orebody was much larger than the original orebodies in the region. The entire Pipeline complex contained 23 million ounces of gold between the original orebodies, the Pipeline orebody and the discoveries of South Pipeline, Crossroads. The Cortez Joint Venture built the Pipeline Mine and mill in early 1996 following a series of disputes with junior mining companies. Commissioning of the Pipeline mine cost US$250 million, and resulted an annual output between 1998 and 2005 of over one million ounces of gold per year, the Cortez Hills deposit was discovered in 2002, underground development to define the resource limits began in 2006. Barrick Gold acquired 60% in Cortez in 2006 when it purchased Placer Dome for US$10.4 billion, the Cortez Mine is located in the Crescent Valley which is between the Shoshone and Cortez Mountains, a basin in the traditional Basin and Range setting of Nevada. Precious metal mineralization came during Jurassic-Miocene periods, the Pipeline complex lies within 600 feet of silty limestone in what is called the Silurian Roberts Mountain Formation. Above this is Devonian Wenban Limestone, which acts as the host rock of the Cortez Hills deposit, above the Devonian Limestone is Quaternary alluvium. Current haulage rates at Cortez are 350, 000–400,000 short tons per day of combined ore and waste, Cortez currently has an average stripping ratio of 3,1. Ore in the pit mines is hauled on surface using 400-short-ton Liebherr T282B trucks. Cortez currently owns 24 T282Bs, which accounts for 10% of the sales of T282 & T282B trucks worldwide
Cortez Gold Mine
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Abandoned mill in the Cortez Gold Mine Complex at the Abandoned town of Cortez
Cortez Gold Mine
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A Liebherr T282B 400 ton truck, the same model is in operation at the open pits at Cortez.
32.
Round Mountain Gold Mine
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The Round Mountain Gold Mine is an open pit gold mine in Round Mountain, Nevada. The mine is operated and owned by Kinross Gold, mining at Round Mountain occurred as early as 1906, using underground techniques. The mine produced 350,000 ounces of gold through underground mining over a sixty-year period, in 2003 Kinross acquired 50% of the Round Mountain mine from Echo Bay Mines through a merger. In 2016, Kinross purchased the remaining 50% from Barrick Gold Corporation, the Round Mountain Gold Mine is owned and operated by Kinross Gold. Until early in 2016, it was a 50-50 joint venture between Barrick Gold and Kinross Gold, with Kinross as the operator, the mine is 55 miles north of the town of Tonopah, with a workforce of approximately 750 people. In 2010, expansion of the mine was approved by the Bureau of Land Management, the expansion would include increasing the depth and width of the pit, and increasing the capacity of related mining and mineral processing infrastructure. The expansion was appealed by the non-governmental organizations Great Basin Resource Watch, the groups also appealed the construction of Gold Hill, a second pit near Round Mountain, that is part of the expansion. As of summer 2011, road construction and environmental mitigation began for the Round Hill expansion, ore from the Gold Hill site is processed on site on a leach pad, while the pouring of gold bars takes place at the Round Mountain facility. The Round Mountain Mine is a low sulfidation epithermal deposit
Round Mountain Gold Mine
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Aerial photo of Round Mountain open pit in 2008
Round Mountain Gold Mine
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Gold specimen from Round Mountain, size 2.0 x 1.8 x 0.7 cm.
33.
Turquoise Ridge Gold Mine
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The Getchell Mine is an underground gold mine in the Potosi Mining District of Humboldt County, Nevada, on the east flank of the Osgood Mountains,35 miles northeast of Winnemucca. Prospectors Edward Knight and Emmet Chase discovered gold in 1933 and located the first claims in 1934, with the financial backing of Noble Getchell and George Wingfield, the Getchell Mine, Inc. was organized in 1936 and the mine was brought into production in 1938. The mining operation currently consists of two mines, Getchell and Turquoise Ridge, operated as the Turquoise Ridge Joint Venture. Barrick Gold is operator and 75% owner with Newmont Mining owning the remaining 25%, the mining method currently used is underhand cut-and-fill. The refractory gold ore is treated by pressure oxidation technology at the Twin Creeks Sage autoclave, the gold deposit is a sediment-hosted disseminated Carlin–type deposit, with sub-micron sized gold distributed in pyrite and marcasite. The mineral getchellite, a sulfide of arsenic and antimony, AsSbS3, was discovered at. The occurrence of gold at the Getchell Mine, Nevada, timing of Gold and Arsenic Sulfide Mineral Deposition at the Getchell Carlin-Type Gold Deposit, North-Central Nevada. Archived from the original on 2011-07-27
Turquoise Ridge Gold Mine
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Realgar from the Getchell Mine. Characteristic traces of silver, arsenic, antimony, mercury, thallium and barium are associated with Carlin-type mineralization, and are widely used as pathfinders in geochemical prospecting for gold.
34.
Pascua Lama
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Pascua-Lama is an open pit mining project of gold, silver, copper and other minerals. Pascua Lama is located in the Andes mountains, in the reaches of Atacama Desert. Toronto-based Barrick Gold, the worlds largest gold mining company, is developing the project, due to its proximity to glaciers, Pascua-Lama has caused controversy and public protest in Chile, including demonstrations and petitions presented to the Chilean government. Chile has not approved the project, Pascua-Lama contains estimated deposits of 17 million ounces of gold and 635 million ounces of silver, with 75 percent of the deposits in Chile and 25 percent in Argentina. There is a long-running Court action in Chile found on the Courts website, initiated in 2001 by a mining agent. All of these Claims are located superimposed partially over Barricks Pascua Lama mine, c-1912-2001 was filed in the 14th Civil Court of Santiago. Barrick found it necessary to order its mining agent, Unda Llanos and this treaty permits investors to explore and exploit mineral deposits that straddle the border between the two countries. In 2000, an appeal was filed with the Chilean Constitutional Court to rule the treaty unconstitutional, alcayaga, Luna, and Padilla, analyzing the treaty, have concluded that, both in terms of content and form, contains provisions that violate Chiles constitution. Nevertheless, nothing came of the lawsuit, and Chiles National Environmental Commission issued its approval for the Pascua Lama project on 13 June 2006. Barrick has been planning the project for several years, Barricks plans for the project have changed over time. In June 2005, Barrick intended to commence building in January 2006, after responding to a questionnaire put to it by CONAMA and this change was publicly supported by Fernando González, the chairman of the council of Huasco Valley farmers. Another report by the organization also focused on glacier impacts by Barrick Gold to the lands belonging to the Diguita Huascoaltino community in Chile. The banks were set to provide Barrick Gold with significant start up loans for the project, other environmental organizations in Canada, Chile and Argentina were also providing information to the banks, discouraging financing to Barrick for Pascua Lama. In March 2012, both EDC and Exim Bank announced that the Barrick deal had fallen through, in 2012, in the context of the costs of water usage in mining globally, Barricks escalating costs for the Pascua Lama mine were reviewed. As of November 1,2012, Barrick had spent $3.7 billion on Pascua Lama, in all, it plans to invest between $8 and $8.5 billion to bring the project into production. But if the past is any guide, those costs could rise, Pascua Mine project of Barrick Chiles gold mine is located at 5,000 meters elevation at the crest of the Central Andes. The Pascua Mine hill and mountains within a few kilometers of the southeast are called the Cerros Nevados, an environmental acid rock drainage baseline report was submitted in 1999. Report authors noted the importance of agriculture of the Rio Huasco valley, whose river, three surface water courses drain the Pascua Mine hill, the Rio Del Estrecho on the northwest side, Rio El Toro on the southwest side, and Arroyo Turbio on the east side
Pascua Lama
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Satellite view of the project area showing the Pascua-Lama open pit in red
35.
Super Pit gold mine
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The Fimiston Open Pit, colloquially known as the Super Pit, was Australias largest open cut gold mine until 2016 when it was surpassed by the Newmont Boddington gold mine also in Western Australia. The Super Pit is located off the Goldfields Highway on the south-east edge of Kalgoorlie, the pit is oblong in shape and is approximately 3.5 kilometres long,1.5 kilometres wide and 570 metres deep. At these dimensions, it is enough to be seen from space. The Super Pit is owned by Kalgoorlie Consolidated Gold Mines Pty Ltd, the mine produces 850,000 ounces of gold per year, and employs around 550 employees directly on site. Originally consisting of a number of underground mines, consolidation into a single open pit mine was attempted by Alan Bond. The Super Pit was eventually created in 1989 by Kalgoorlie Consolidated Gold Mines Pty Ltd, Barrick Gold acquired its share of the mine in December 2001, when it took over Homestake Mining Company. Newmont became part-owner of the three months later, when it acquired Normandy Mining in February 2002. Most of the gold mined in the Super Pit occurs within ore lodes formed by ancient shears in a rock unit called the Golden Mile Dolerite. Mining is via conventional drill and blast mining via face shovels, around 15 million tonnes of rock is moved in any given year, consisting primarily of waste rock. Gold within the Golden Mile lode system is unusual in that it is present as telluride minerals within pyrite and this is then roasted at a small smelter outside Kalgoorlie-Boulder to liberate the gold from the tellurides, with doré bars poured. Past production figures were, Kalgoorlie Consolidated Gold Mines Pty Ltd
Super Pit gold mine
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Super Pit gold mine, c. 2005
Super Pit gold mine
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Gold mines in the Kalgoorlie region
36.
Goldstrike mine
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Goldstrike is a gold mine in Eureka County in north-eastern Nevada. It is located on the Carlin Trend, a gold mining district. It is owned and operated by the worlds largest gold mining company, Goldstrike is the largest gold mine in North America. Since Barrick acquired Goldstrike in 1986 it has produced 42 million ounces of gold, the first discovery of gold in the Goldstrike property was in 1962 by Atlas Minerals. Gold was first mined from the upper, well-oxidized portion of became the Post deposit in 1975 by PanCana Minerals Ltd. in a small open-pit heap leach operation. In 1978, Western State Minerals Corporation entered into a joint venture with PanCana, the JV delineated ore reserves for the Post deposit in 1986. Barrick acquired 100% ownership of the property in December 1986, the Goldstrike mine complex is the largest Carlin-type mine in the world. The Goldstrike mine adjoins Newmont Minings Carlin mine complex, Goldstrike is northwest of the Carlin mine on the Carlin Trend. Like most Carlin type gold deposits in Nevada the gold was deposited in carbonate or silicate sedimentary rocks. The source of the heat was magmatic but the mechanism is still under debate. The Betze-Post deposits are up to 6,000 feet long,600 feet thick and 800 feet wide, in 2007 the average processed gold grade was 0.136 troy ounces per ton of ore, with a recovery rate of 85. 5%. The Goldstrike complex consists of three mines, the large Betze-Post open-pit mine, and the Meikle and Rodeo underground mines. The ore from all three mines is milled, oxidixed in either a roaster or an autoclave, then leached in either a carbon-in-leach cyanidation circuit or a calcium thiosulfate circuit, the two treatment facilities treat ores from both the open pit and underground mines. Recovered gold is processed into doré on-site and shipped to outside refineries for processing into gold bullion. In 2015 the Betze-Post open-pit mine produced 642,493 oz of gold and 87,223 oz of silver and this was 24% of the total 5,339,659 oz output of all gold mining operations in Nevada for 2015. In 2016 Goldstrike produced 1,096,000 ounces of gold, Barrick Gold Corporation website Barrick Goldstrike - mine tour 2000, photo gallery at Flickr A Guide to the Gold Strike Mine records, 99-63. Special Collections, University Libraries, University of Nevada, Reno
Goldstrike mine
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Goldstrike Mine seen from an altitude of 38,000 feet
Goldstrike mine
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Millerite - Arsenian Pyrite specimen from the underground Meikle mine, Goldstrike complex.
