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99-461: Coal mining is the process of extracting coal from the ground or from a mine. Coal is valued for its energy content and since the 1880s has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United Kingdom and South Africa , a coal mine and its structures are a colliery ,

198-418: A coal handling and preparation plant ( CHPP ), coal handling plant , prep plant , tipple or wash plant ) is a facility that washes coal of soil and rock , crushes it into graded sized chunks (sorting), stockpiles grades preparing it for transport to market, and more often than not, also loads coal into rail cars, barges, or ships. The more of this waste material that can be removed from coal,

297-702: A 70% increase over the 20 years since 1999. In 2018, the world production of brown coal (lignite) was 803.2 Mt, with Germany the world's largest producer at 166.3 Mt. China is most likely the second largest producer and consumer of lignite globally although specific lignite production data is not made available. Coal production has grown fastest in Asia, while Europe has declined. Since 2011, world coal production has been stable, with decreases in Europe and US offset by increases from China, Indonesia and Australia. The top coal mining nations are: Energy production from coal mining

396-452: A certain rate and natural processes will restore them. In contrast, many extractive industries rely heavily on non-renewable resources that can only be extracted once. Natural resource allocations can be at the centre of many economic and political confrontations both within and between countries. This is particularly true during periods of increasing scarcity and shortages ( depletion and overconsumption of resources). Resource extraction

495-500: A coal mine is called a "pit", and above-ground mining structures are referred to as a " pit head ". In Australia , "colliery" generally refers to an underground coal mine. Coal mining has had many developments in recent years, from the early days of men tunneling, digging, and manually extracting the coal on carts to large open-cut and longwall mines. Mining at this scale requires the use of draglines , trucks, conveyors , hydraulic jacks , and shearers. The coal mining industry has

594-464: A coal seam occurring near the top of a ridge or hill, the entire top is removed in a series of parallel cuts. Overburden is deposited in nearby valleys and hollows. This method usually leaves the ridge and hilltops as flattened plateaus. The process is highly controversial for the drastic changes in topography, the practice of creating head-of-hollow-fills , or filling in valleys with mining debris, and for covering streams and disrupting ecosystems. Spoil

693-901: A country's wealth; however, a sudden inflow of money caused by a resource boom can create social problems including inflation harming other industries (" Dutch disease ") and corruption, leading to inequality and underdevelopment, this is known as the " resource curse ". Extractive industries represent a large growing activity in many less-developed countries but the wealth generated does not always lead to sustainable and inclusive growth . People often accuse extractive industry businesses as acting only to maximize short-term value, implying that less-developed countries are vulnerable to powerful corporations. Alternatively, host governments are often assumed to be only maximizing immediate revenue . Researchers argue there are areas of common interest where development goals and business cross. These present opportunities for international governmental agencies to engage with

792-404: A fourth of the world's energy. Coal extraction methods vary depending on whether the mine is an underground mine or a surface (also called an open cast) mine. Additionally, coal seam thickness and geology are factors in the selection of a mining method. The most economical method of coal extraction for surface mines is the electric shovel or drag line. The most economical form of underground mining

891-403: A greater proportion of the coal deposit than underground methods, as more of the coal seams in the strata may be exploited. This equipment can include the following: Draglines which operate by removing the overburden, power shovels, large trucks in which transport overburden and coal, bucket wheel excavators, and conveyors. In this mining method, explosives are first used in order to break through

990-439: A large dining-room table, but with hydraulic jacks for legs. After the large pillars of coal have been mined away, the mobile roof support's legs shorten and it is withdrawn to a safe area. The mine roof typically collapses once the mobile roof supports leave an area. There are six principal methods of underground mining: Coal is mined commercially in over 50 countries. 7,921 million metric tons (Mt) of coal were produced in 2019,

1089-509: A large variability of moisture and maximum particle size. Coal needs to be stored at various stages of the preparation process, and conveyed around the CPP facilities. Coal handling is part of the larger field of bulk material handling , and is a complex and vital part of the CPP. Stockpiles provide surge capacity to various parts of the CPP. ROM coal is delivered with large variations in production rate of tonnes per hour (tph). A ROM stockpile

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1188-559: A long history of significant negative environmental impacts on local ecosystems, health impacts on local communities and workers, and contributes heavily to the global environmental crises, such as poor air quality and climate change . For these reasons, coal has been one of the first fossil fuels to be phased out of various parts of the global energy economy . The major coal producing countries, though, such as China , Indonesia, India and Australia , have not reached peak production, with production increases replacing falls in Europe and

1287-465: A major source of social unrest and conflicts in developing nations. At present, there is a particular concern for rainforest regions that hold most of the Earth's biodiversity. According to Nelson, deforestation and degradation affect 8.5% of the world's forests with 30% of the Earth's surface already cropped. If we consider that 80% of people rely on medicines obtained from plants and 3 ⁄ 4 of

1386-446: A method that currently accounts for about 60 percent of world coal production. In deep mining, the room and pillar or bord and pillar method progresses along the seam, while pillars and timber are left standing to support the mine roof. Once room and pillar mines have been developed to a stopping point limited by geology, ventilation, or economics, a supplementary version of room and pillar mining, termed second mining or retreat mining ,

1485-470: A new coal mine. Resource extraction Natural resources are part of humanity's natural heritage or protected in nature reserves . Particular areas (such as the rainforest in Fatu-Hiva ) often feature biodiversity and geodiversity in their ecosystems. Natural resources may be classified in different ways. Natural resources are materials and components (something that can be used) found within

1584-588: A result of occupational exposures is coined occupational hearing loss . To protect miners' hearing, the US Mine Safety and Health Administration 's (MSHA) guidelines for noise place a Permissible Exposure Limit (PEL) for noise at 90 dBA time-weighted over 8 hours. A lower cutoff, 85 dBA, is set for a worker to fall into the MSHA Action Level which dictates that workers be placed into hearing conservation programs. Noise exposures vary depending on

1683-515: Is a type of land management that seeks to conserve , protect and restore habitat areas for wild plants and animals , especially conservation reliant species , and prevent their extinction, fragmentation or reduction in range . Natural resource management is a discipline in the management of natural resources such as land, water , soil , plants , and animals —with a particular focus on how management affects quality of life for present and future generations. Hence, sustainable development

1782-412: Is a very important part of a CPP. Measurement of flow, density, levels, ash and moisture are inputs to the control system. PLCs are used extensively in plant design. SCADA systems are typically used to control the process. Other instrumentation found in plants include density gauges and online elemental coal analyzers . In 1810, German Ernst Friedrich Wilhelm Lindig , coal mining pioneer, invented

1881-575: Is accomplished by drilling holes into the overburden, filling the holes with explosives, and detonating the explosive. The overburden is then removed, using large earth-moving equipment, such as draglines , shovel and trucks, excavator and trucks, or bucket-wheels and conveyors. This overburden is put into the previously mined (and now empty) strip. When all the overburden is removed, the underlying coal seam will be exposed (a 'block' of coal). This block of coal may be drilled and blasted (if hard) or otherwise loaded onto trucks or conveyors for transport to

1980-529: Is also a major source of human rights violations and environmental damage. The Sustainable Development Goals and other international development agendas frequently focus on creating more sustainable resource extraction, with some scholars and researchers focused on creating economic models, such as circular economy , that rely less on resource extraction, and more on reuse , recycling and renewable resources that can be sustainably managed. There are various criteria for classifying natural resources. These include

2079-438: Is another factor causing depletion of natural resources. For example, the depletion of nutrients in the soil due to excessive use of nitrogen and desertification . The depletion of natural resources is a continuing concern for society. This is seen in the cited quote given by Theodore Roosevelt , a well-known conservationist and former United States president, who was opposed to unregulated natural resource extraction. In 1982,

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2178-402: Is being shipped. The sampler is set according to Tons per hour, Feet per minute and top size of the product on the actual belt. A sample is taken then crushed, then sub sampled and returned to the main belt. The sample is sent to an Independent lab for testing where the results will be shared with the buyer as well as the supplier. The buyer in many cases will also sample the coal again once it

2277-426: Is commonly started. Miners remove the coal in the pillars, thereby recovering as much coal from the coal seam as possible. A work area involved in pillar extraction is called a pillar section. Modern pillar sections use remote-controlled equipment, including large hydraulic mobile roof-supports, which can prevent cave-ins until the miners and their equipment have left a work area. The mobile roof supports are similar to

2376-510: Is considered a sustainable development issue. The term sustainable development has many interpretations, most notably the Brundtland Commission's 'to ensure that it meets the needs of the present without compromising the ability of future generations to meet their own needs'; however, in broad terms it is balancing the needs of the planet's people and species now and in the future. In regards to natural resources, depletion

2475-437: Is constrained creates an outer spiral. The existence of a top central outlet and inability for all the fluid to leave at the cone apex outlet, assist the inward migration of some of the fluid from the external moving mass. The amount of inward migration increases as the apex is neared, i.e. the radius decreased and the fluid which flows in this migratory stream, ultimately reverses its vertical velocity direction and flows upward to

2574-544: Is determined by the manner in which the mining is conducted. Usually reclamation of disturbed lands to a land use condition is not equal to the original use. Existing land uses (such as livestock grazing, crop and timber production) are temporarily eliminated in mining areas. High-value, intensive-land-use areas like urban and transportation systems are not usually affected by mining operations. If mineral values are sufficient, these improvements may be removed to an adjacent area. Strip mining eliminates existing vegetation, destroys

2673-417: Is followed according to the judicious use of resources to supply present and future generations. The disciplines of fisheries, forestry, and wildlife are examples of large subdisciplines of natural resource management. Management of natural resources involves identifying who has the right to use the resources and who does not to define the management boundaries of the resource. The resources may be managed by

2772-514: Is highly concentrated in certain jurisdictions, which also concentrates much of the social and economic impacts of the industry to these regions. The industry directly employs over seven million workers worldwide, which, in turn, creates millions of indirect jobs. In several parts of the world, producers have reached peak coal as some economies shift away from fossil fuels to address climate change. A 2020 study found that renewables jobs could feasibly be created in these geographies to replace many of

2871-481: Is mostly used to generate electricity, and 75% of annual coal production is exported, mostly to eastern Asia. In 2007, 428 million tonnes of coal was mined in Australia. In 2007, coal provided about 85% of Australia's electricity production. In the fiscal year 2008/09, 487 million tonnes of coal was mined, and 261 million tonnes was exported. In the fiscal year 2013/14, 430.9 million tonnes of coal

2970-596: Is of concern for sustainable development as it has the ability to degrade current environments and the potential to impact the needs of future generations. "The conservation of natural resources is the fundamental problem. Unless we solve that problem, it will avail us little to solve all others." Theodore Roosevelt Depletion of natural resources is associated with social inequity . Considering most biodiversity are located in developing countries, depletion of this resource could result in losses of ecosystem services for these countries. Some view this depletion as

3069-414: Is partially economically recoverable. Coal refuse is distinct from the byproducts of burning coal, such as fly ash . Piles of coal refuse can have significant negative environmental consequences, including the leaching of iron, manganese, and aluminum residues into waterways and acid mine drainage . The runoff can create both surface and groundwater contamination. The piles also create a fire hazard, with

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3168-592: Is placed at the head of a narrow, steep-sided valley or hollow. In preparation for filling this area, vegetation and soil are removed and a rock drain constructed down the middle of the area to be filled, where a natural drainage course previously existed. When the fill is completed, this underdrain will form a continuous water runoff system from the upper end of the valley to the lower end of the fill. Typical head-of-hollow fills are graded and terraced to create permanently stable slopes. Most coal seams are too deep underground for opencast mining and require underground mining,

3267-404: Is pumped tangentially to a tapered inlet and short cylindrical section at a predetermined flowrate and pressure followed by a conical section where the separation takes place. The higher specific gravity fractions being subject to greater centrifugal forces pull away from the central core and descend downwards towards the apex along the wall of cyclone body and pass out as rejects/middlings through

3366-423: Is received to "double check" the results. Continuous measurement of ash, moisture, kCal (BTU), sulfur Fe, Ca, Na, and other element constituents of the coal are reported by cross belt elemental analyzers. This information can be calibrated periodically to the lab data per methods. The washability characteristics of a coal reserve are provided by obtaining liberation data on the raw coal sample. Liberation refers to

3465-434: Is referred to as 'overburden' and is removed in long strips. The overburden from the first strip is deposited in an area outside the planned mining area and referred to as out-of-pit dumping. Overburden from subsequent strips is deposited in the void left from mining the coal and overburden from the previous strip. This is referred to as in-pit dumping. It is often necessary to fragment the overburden by use of explosives. This

3564-513: Is removed and overburden dumped to the side. Dust, vibration, and diesel exhaust odors are created (affecting sight, sound, and smell). Residents of local communities often find such impacts disturbing or unpleasant. In case of mountaintop removal , tops are removed from mountains or hills to expose thick coal seams underneath. The soil and rock removed is deposited in nearby valleys, hollows and depressions, resulting in blocked (and contaminated) waterways. Removal of soil and rock overburden covering

3663-412: Is removed from tailings to recycle water. Filters, centrifuges and thickeners are used in this part of the process. The blackwater is a form of tailings . It is produced as a by-product is typically placed in a coal slurry impoundment, which can be sources of environmental disasters. Thickeners are used for dewatering slurries of either tailings or product. A thickener is a large circular tank that

3762-710: Is still common, with 4,000 new cases of black lung every year in the US (4 percent of workers annually) and 10,000 new cases every year in China (0.2 percent of workers). The use of water sprays in mining equipment reduces the risk to miners' lungs. Build-ups of a hazardous gas are known as damps, possibly from the German word Dampf which means steam or vapor: Noise is also a contributing factor to potential adverse effects on coal miners' health. Exposure to excessive noise can lead to noise-induced hearing loss . Hearing loss developed as

3861-464: Is the long wall, which involves using two spinning drums with carbide bits that runs along sections of the coal seam. Many coals extracted from both surface and underground mines require washing in a coal preparation plant . Technical and economic feasibility are evaluated based on the following: regional geological conditions; overburden characteristics; coal seam continuity, thickness, structure, quality, and depth; strength of materials above and below

3960-666: Is the scientific study of the nature and status of Earth's biodiversity with the aim of protecting species , their habitats , and ecosystems from excessive rates of extinction . It is an interdisciplinary subject drawing on science, economics and the practice of natural resource management . The term conservation biology was introduced as the title of a conference held at the University of California, San Diego , in La Jolla, California, in 1978, organized by biologists Bruce A. Wilcox and Michael E. Soulé . Habitat conservation

4059-434: Is used for both thermal and metallurgical coals . In New South Wales open casting for steam coal and anthracite is practiced. Surface mining accounts for around 80 percent of production in Australia, while in the US it is used for about 67 percent of production. Globally, about 40 percent of coal production involves surface mining. Strip mining exposes coal by removing earth above each coal seam. This earth to be removed

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4158-442: Is used to allow the washplant to be fed coal at lower, constant rate. A simple stockpile is formed by machinery dumping coal into a pile, either from dump trucks , pushed into heaps with bulldozers or from conveyor booms. More controlled stockpiles are formed using stackers to form piles along the length of a conveyor, and reclaimers to retrieve the coal when required for product loading, etc. Taller and wider stockpiles reduce

4257-400: Is used to settle out the solid material from the water in the feed slurry. The separated water is clarified and reused as process water in the CPP. Thickeners are sized according to the volume of feed slurry to be processed. Typical size ranges are from 13 to 40m in diameter and 3-4m high. The floor of the thickener is conical, sloping gently down toward the centre. The feed is pumped into

4356-490: The Industrial Revolution , and coal provided the main source of primary energy for industry and transportation in industrial areas from the 18th century to the 1950s. Coal remains an important energy source. Coal is also mined today on a large scale by open pit methods wherever the coal strata strike the surface or are relatively shallow. Britain developed the main techniques of underground coal mining from

4455-583: The United Nations developed the World Charter for Nature , which recognized the need to protect nature from further depletion due to human activity. It states that measures must be taken at all societal levels, from international to individual, to protect nature. It outlines the need for sustainable use of natural resources and suggests that the protection of resources should be incorporated into national and international systems of law. To look at

4554-552: The private sector and host governments through revenue management and expenditure accountability, infrastructure development, employment creation , skills and enterprise development , and impacts on children, especially girls and women. A strong civil society can play an important role in ensuring the effective management of natural resources. Norway can serve as a role model in this regard as it has good institutions and open and dynamic public debate with strong civil society actors that provide an effective checks and balances system for

4653-472: The American Society for Testing and Materials ( ASTM ). A cross cut sampler mounts directly on top of the conveyor belt, the falling stream sampler is placed at the head section of the belt. There are several points in the wash plant that many coal operations choose to sample. The raw coal, before it enters the plant. The refuse, to see what the plant missed. Then the clean coal, to see exactly what

4752-808: The U.S., Examples include the Sago Mine disaster of 2006, and the 2007 mine accident in Utah 's Crandall Canyon Mine , where nine miners were killed and six entombed. In the decade 2005–2014, US coal mining fatalities averaged 28 per year. The most fatalities during the 2005–2014 decade were 48 in 2010, the year of the Upper Big Branch Mine disaster in West Virginia, which killed 29 miners. Chronic lung diseases, such as pneumoconiosis (black lung) were once common in miners, leading to reduced life expectancy . In some mining countries black lung

4851-670: The United States and proposed mines under development. The coal mining industry employs almost 2.7 million workers. The History of coal mining goes back thousands of years, with early mines documented in ancient China, the Roman Empire and other early historical economies. It became important in the Industrial Revolution of the 19th and 20th centuries, when it was primarily used to power steam engines, heat buildings and generate electricity. Coal mining continues as an important economic activity today, but has begun to decline due to

4950-568: The amount of physical breakage required to liberate coal from different other material densities. Low density material is clean coal whereas high density material is reject (rock). The intermediate density material is called middlings . Liberation data is commonly obtained by float and sink analysis. The procedures for this analysis are detailed in Australian Standard AS 4156.1 – 1994 "Coal preparation — Higher rank coal — Float and sink testing". Crushing reduces

5049-470: The circuit or the feed. Fine coal is cleaned using froth flotation methods. Denver cells and Jameson Cells are two flotation methods used. Spirals perform a simple, low cost and reasonably efficient separation of finer sized material, based on particle density and size. Water is removed from the product to reduce the mass, and runoff on the stockpile. Different methods of dewatering exist, including: Coarse coal dewatering: Fine coal dewatering: Water

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5148-399: The coal into feeders. Sometimes front-end loaders are the only means of reclaiming coal from the stockpile. This has a low up-front capital cost, but much higher operating costs, measured in dollars per tonne handled. High-capacity stockpiles are commonly reclaimed using bucket-wheel reclaimers . These can achieve very high rates. Sampling of coal is an important part of process control in

5247-579: The coal mining jobs as part of a just transition ; however, renewable energy was not suitable in some of the geographies with high concentrations of miners, such as in China, which is far and away the leading coal-mining nation. Coal refuse (also described as coal waste, rock, slag, coal tailings, waste material, rock bank, culm, boney, or gob) is the material left over from coal mining, usually as tailings piles or spoil tips . For every tonne of hard coal generated by mining, 400 kg (880 lb) of waste material remains, which includes some lost coal that

5346-495: The coal preparation (or wash) plant. Once this strip is empty of coal, the process is repeated with a new strip being created next to it. This method is most suitable for areas with flat terrain. Equipment to be used depends on geological conditions. For example, to remove overburden that is loose or unconsolidated, a bucket wheel excavator might be the most productive. The life of some area mines may be more than 50 years. The contour mining method consists of removing overburden from

5445-860: The coal resource may cause burial and loss of topsoil, exposes parent material, and creates large infertile wastelands. Soil disturbance and associated compaction result in conditions conducive to erosion. Soil removal from the area to be surface-mined alters or destroys many natural soil characteristics, and reduces its biodiversity and productivity for agriculture. Soil structure may be disturbed by pulverization or aggregate breakdown. Top 10 hard and brown coal producers in 2012 were (in million metric tons): China 3,621, United States 922, India 629, Australia 432, Indonesia 410, Russia 351, South Africa 261, Germany 196, Poland 144, and Kazakhstan 122. Coal has been mined in every state of Australia, but mainly in Queensland, New South Wales and Victoria. It

5544-465: The cyclone over flow outlet, i.e. vortex finder. Since it is at the same time rotating, the result is an inner spiral. The Heavy Media Cyclone may be lined with very high quality ceramic tiles or manufactured from Ni-hard (a very hard alloy of cast iron containing nickel) with a specially designed helical profile. A cyclone is the heart of the washing unit in a Heavy Media Washery. It is a non moving part and hence requires very low maintenance. However,

5643-414: The decrease in pressure more coal shall report to the discard/middlings, thus impairing the efficiency of separation. If due to some reason the cyclone feed pump is not being able to deliver the required pressure at the inlet of the cyclone, feed should immediately be stopped and the pipelines, tank and pump should be properly checked for any jamming and any jamming should be properly cleaned before starting

5742-427: The developed world. Modern coal mining in the US has an average 23 deaths per year due to mine accidents (2001–2020). However, in lesser developed countries and some developing countries, many miners continue to die annually, either through direct accidents in coal mines or through adverse health consequences from working under poor conditions. China , in particular, has the highest number of coal mining related deaths in

5841-439: The different relative densities of different grades of coal, and the reject material. Jigs are a gravity separation method for coarse coal. Different types of wet jig include: Dense medium gravity separation methods use a material such as magnetite to form a medium denser than water to assist in separation. Different types of DMB include: A cyclone is a conical vessel in which coal along with finely ground magnetite (media)

5940-453: The disruptive activities of blasting, ripping, and excavating coal. Stripping of overburden eliminates and destroys archeological and historic features, unless they are removed beforehand. The removal of vegetative cover and activities associated with the construction of haul roads, stockpiling of topsoil, displacement of overburden and hauling of soil and coal increase the quantity of dust around mining operations. Dust degrades air quality in

6039-515: The environment. Every man-made product is composed of natural resources (at its fundamental level). A natural resource may exist as a separate entity such as freshwater, air , or any living organism such as a fish, or it may be transformed by extractivist industries into an economically useful form that must be processed to obtain the resource such as metal ores , rare-earth elements , petroleum , timber and most forms of energy . Some resources are renewable , which means that they can be used at

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6138-569: The fatalities occurring in the first half of the 20th century. 3,242 died in 1907, the worst year ever; in 2020 there were five. Open cut hazards are principally mine wall failures and vehicle collisions; underground mining hazards include suffocation, gas poisoning, roof collapse, rock burst , outbursts , and gas explosions. Firedamp explosions can trigger the far more dangerous coal dust explosions, which can engulf an entire mine. Most of these risks are greatly reduced in modern mines, and multiple fatality incidents are now rare in most parts of

6237-449: The feedwell, at the centre of the thickener, near the top. The feed is normally dosed with flocculant before delivery to the thickener. The thickened mass is moved toward the bottom centre of the thickener by large rakes that rotate around the tank. Rotation speed is very slow, and drive torques can be high, especially for larger diameter thickeners. Drive torque is usually monitored continuously, as high densities could cause failure of

6336-456: The genetic soil profile, displaces or destroys wildlife and habitat, alters current land uses, and to some extent permanently changes the general topography of the area mined. Adverse impacts on geological features of human interest may occur in a coal strip mine. Geomorphic and geophysical features and outstanding scenic resources may be sacrificed by indiscriminate mining. Paleontological, cultural, and other historic values may be endangered due to

6435-567: The government as in Norway's case, natural resources can actually be a factor in whether a civil war starts and how long the war lasts. In recent years, the depletion of natural resources has become a major focus of governments and organizations such as the United Nations (UN). This is evident in the UN's Agenda 21 Section Two, which outlines the necessary steps for countries to take to sustain their natural resources. The depletion of natural resources

6534-510: The government's management of extractive industries, such as the Extractive Industries Transparency Initiative (EITI), a global standard for the good governance of oil, gas and mineral resources. It seeks to address the key governance issues in the extractive sectors. However, in countries that do not have a very strong and unified society, meaning that there are dissidents who are not as happy with

6633-448: The immediate area, has an adverse impact on vegetative life, and constitutes health and safety hazards for mine workers and nearby residents. Surface mining disrupts virtually all aesthetic elements of the landscape. Alteration of land forms often imposes unfamiliar and discontinuous configurations. New linear patterns appear as material is extracted and waste piles are developed. Different colors and textures are exposed as vegetative cover

6732-661: The importance of protecting natural resources further, the World Ethic of Sustainability, developed by the IUCN , WWF and the UNEP in 1990, set out eight values for sustainability, including the need to protect natural resources from depletion. Since the development of these documents, many measures have been taken to protect natural resources including establishment of the scientific field and practice of conservation biology and habitat conservation, respectively. Conservation biology

6831-742: The industry cut the rate of injuries by more than half and fatalities by two-thirds. But according to the Bureau of Labor Statistics , even in 2006, mining remained the second most dangerous occupation in America, when measured by fatality rate . These numbers, however, include all mining activities, and oil and gas mining contribute to the majority of fatalities. Coal mining resulted in 47 fatalities that year. One study, though, has suggested that hazards of modern mining are now more accretive with workers facing long-term health impacts, such as sleep deprivation, that build up over time. Strip mining severely alters

6930-442: The land area required to store a set tonnage of coal. Larger coal stockpiles have a reduced rate of heat loss, leading to a higher risk of spontaneous combustion. Travelling, luffing boom stackers that straddle a feed conveyor are commonly used to create coal stockpiles. Tunnel conveyors can be fed by a continuous slot hopper or bunker beneath the stockpile to reclaim material. Front-end loaders and bulldozers can be used to push

7029-424: The landscape, which reduces the value of the natural environment in the surrounding land. The land surface is dedicated to mining activities until it can be reshaped and reclaimed. If mining is allowed, resident human populations must be resettled off the mine site; economic activities, such as agriculture or hunting and gathering food and medicinal plants are interrupted. What becomes of the land surface after mining

7128-459: The late 18th century onward, with further progress being driven by 19th-century and early 20th-century progress. However, oil and gas were increasingly used as alternatives from the 1860s onward. By the late 20th century, coal was, for the most part, replaced in domestic as well as industrial and transportation usage by oil , natural gas or electricity produced from oil, gas, nuclear power or renewable energy sources. By 2010, coal produced over

7227-491: The lower its total ash content , the greater its market value and the lower its transportation costs . The coal delivered from the mine that reports to the coal preparation plant is called run-of-mine, or ROM, coal. This is the raw material for the CPP, and consists of coal, rocks, middlings, minerals and contamination. Contamination is usually introduced by the mining process and may include machine parts, used consumables and parts of ground engaging tools. ROM coal can have

7326-460: The method of extraction. For example, a study has found that among surface coal mine operations, dragline equipment produced the loudest sound at a range of 88–112 dBA. Within longwall sections, stageloaders used to transport coal from the mining face and shearers used for extraction represent some of the highest noise exposures. Auxiliary fans (up to 120 dBA), continuous mining machines (up to 109 dBA), and roof bolters (up to 103 dBA) represent some of

7425-462: The mining workforce. in 2015 US coal mines had 65,971 employees, the lowest figure since EIA began collecting data in 1978. However, a 2016 study reported that a relatively minor investment would allow most coal workers to retrain for the solar energy industry. Coal mining has been a very dangerous activity and the list of historical coal mining disasters is long. In the U.S., 104,895 coal miners were killed in mine accidents since 1900, 90 percent of

7524-404: The nature of the shared resources, the individuals who are affected by the rules can participate in setting or changing them. The users have rights to devise their own management institutions and plans under the recognition by the government. The right to resources includes land, water, fisheries, and pastoral rights. The users or parties accountable to the users have to actively monitor and ensure

7623-467: The noisiest equipment within continuous mining sections. Exposures to noise exceeding 90 dBA can lead to adverse effects on workers' hearing. The use of administrative controls and engineering controls can be used to reduce noise exposures. Improvements in mining methods (e.g. longwall mining), hazardous gas monitoring (such as safety-lamps or more modern electronic gas monitors), gas drainage, electrical equipment , and ventilation have reduced many of

7722-589: The open pit methods, due to thickness of the seam 20–25 metres (60–90 feet). Coals occurring below 90 m (300 ft) are usually deep mined. However, there are open pit mining operations working on coal seams up to 300–460 metres (1,000–1,500 feet) below ground level, for instance Tagebau Hambach in Germany. When coal seams are near the surface, it may be economical to extract the coal using open-cut , also referred to as open-cast, open-pit, mountaintop removal or strip, mining methods. Opencast coal mining recovers

7821-421: The operation reaches a predetermined stripping ratio (tons of overburden/tons of coal), it is not profitable to continue. Depending on the equipment available, it may not be technically feasible to exceed a certain height of highwall. At this point, it is possible to produce more coal with the augering method in which spiral drills bore tunnels into a highwall laterally from the bench to extract coal without removing

7920-657: The overall top size of the ROM coal so that it can be more easily handled and processed within the CPP. Crushing requirements are an important part of CPP design and there are a number of different types. Screens in screening plant are used to group process particles into ranges by size. Dewatering screens are used to remove surface water from the product. Screens can be static, mechanically vibrated or electro-mechanically vibrated. Screen decks can be made from different materials such as spring steel, stainless steel, mild steel or polyurethane (PU). Gravity separation methods make use of

8019-406: The overburden. Mountaintop coal mining is a surface mining practice involving removal of mountaintops to expose coal seams, and disposing of associated mining overburden in adjacent "valley fills." Valley fills occur in steep terrain where there are limited disposal alternatives. Mountaintop removal mining combines area and contour strip mining methods. In areas with rolling or steep terrain with

8118-422: The potential to spontaneously ignite. Because most coal refuse harbors toxic components, it is not easily reclaimed by replanting with plants like beach grasses. The use of sophisticated sensing equipment to monitor air quality is common and has replaced the use of small animals such as canaries, often referred to as " miner's canaries ". In the United States, the increase in technology has significantly decreased

8217-408: The pressure at the inlet of the cyclone is a very important factor and it is suggested to maintain a minimum pressure of around D x 9 x 9.81 x density/100 (in bars), where D = the inner diameter of the cyclone in mm. It is important to note that the pressure at which pulp (mixture of coal and magnetite) is introduced in the cyclone is the principal means of controlling the forces within the cyclone. With

8316-421: The production and marketing of coal. A grab sample is a one-off sample of the coal at a point in the process stream, and tends not to be very representative. A routine sample is taken at a set frequency, either over a period of time or per shipment. Coal sampling consists of several types of sampling devices. A "cross cut" sampler mimics the "stop belt" sampling method specified by a standard originally published by

8415-469: The rakes and drive equipment. Rakes may have the capacity to be raised to reduce drive torque. The thickened slurry, also called thickener underflow, is pumped out of the bottom of the thickener. In the case of product coal, further dewatering is usually required before shipment. Thickened tailings can be pumped to a tailings dam, combined with larger sized rejects for disposal (co-disposal), or dewatered further before disposal. Control and instrumentation

8514-569: The risks of rock falls, explosions, and unhealthy air quality. Gases released during the mining process can be recovered to generate electricity and improve worker safety with gas engines . Another innovation in recent years is the use of closed circuit escape respirators , respirators that contain oxygen for situations where mine ventilation is compromised. Statistical analyses performed by the US Department of Labor's Mine Safety and Health Administration (MSHA) show that between 1990 and 2004,

8613-417: The seam for roof and floor conditions; topography, especially altitude and slope; climate; land ownership as it affects the availability of land for mining and access; surface drainage patterns; groundwater conditions; availability of labor and materials; coal purchaser requirements in terms of tonnage, quality, and destination; and capital investment requirements. Surface mining and deep underground mining are

8712-565: The seam in a pattern following the contours along a ridge or around the hillside. This method is most commonly used in areas with rolling to steep terrain. It was once common to deposit the spoil on the downslope side of the bench thus created, but this method of spoil disposal consumed much additional land and created severe landslide and erosion problems. To alleviate these problems, a variety of methods were devised to use freshly cut overburden to refill mined-out areas. These haul-back or lateral movement methods generally consist of an initial cut with

8811-591: The source of origin, stages of development, renewability and ownership . Resource extraction involves any activity that withdraws resources from nature. This can range in scale from the traditional use of preindustrial societies to global industry. Extractive industries are, along with agriculture, the basis of the primary sector of the economy. Extraction produces raw material , which is then processed to add value . Examples of extractive industries are hunting , trapping , mining , oil and gas drilling , and forestry . Natural resources can add substantial amounts to

8910-431: The spoil deposited downslope or at some other site and spoil from the second cut refilling the first. A ridge of undisturbed natural material 15 to 20 ft (5 to 6 m) wide is often intentionally left at the outer edge of the mined area. This barrier adds stability to the reclaimed slope by preventing spoil from slumping or sliding downhill. The limitations of contour strip mining are both economic and technical. When

9009-556: The strong contribution coal plays in global warming and environmental issues, which result in decreasing demand and in some geographies, peak coal . Compared to wood fuels , coal yields a higher amount of energy per unit mass, specific energy or massic energy, and can often be obtained in areas where wood is not readily available. Though it was used historically as a domestic fuel, coal is now used mostly in industry, especially in smelting and alloy production, as well as electricity generation . Large-scale coal mining developed during

9108-475: The surface or overburden, of the mining area. The overburden is then removed by draglines or by shovel and truck. Once the coal seam is exposed, it is drilled, fractured and thoroughly mined in strips. The coal is then loaded onto large trucks or conveyors for transport to either the coal preparation plant or directly to where it will be used. Most open cast mines in the United States extract bituminous coal . In Canada, Australia, and South Africa, open cast mining

9207-523: The two basic methods of mining. The choice of mining method depends primarily on depth, density, overburden, and thickness of the coal seam; seams relatively close to the surface, at depths less than approximately 55 m (180 ft), are usually surface mined. Coal that occurs at depths of 55 to 90 m (180 to 300 ft) are usually deep mined, but in some cases surface mining techniques can be used. For example, some western U.S. coal that occur at depths in excess of 60 m (200 ft) are mined by

9306-436: The underflow orifice discharge, also known as the spigot. The lighter particles are caught in an upward stream and pass out as clean coal through the cyclone overflow outlet via the vortex finder. From the overflow orifice, the coal goes into the overflow chamber, and is discharged to the next stage of the process. Fluid on entry commences in the outer regions of the cyclone body. This combined with rotational motion to which it

9405-443: The users according to the rules governing when and how the resource is used depending on local condition or the resources may be managed by a governmental organization or other central authority. A "...successful management of natural resources depends on freedom of speech, a dynamic and wide-ranging public debate through multiple independent media channels and an active civil society engaged in natural resource issues..." because of

9504-592: The utilisation of the resource compliance with the rules and impose penalties on those people who violate the rules. These conflicts are resolved quickly and efficiently by the local institution according to the seriousness and context of the offense. The global science-based platform to discuss natural resources management is the World Resources Forum , based in Switzerland. Coal preparation plant A coal preparation plant ( CPP ; known as

9603-487: The world's prescription medicines have ingredients taken from plants, loss of the world's rainforests could result in a loss of finding more potential life-saving medicines. The depletion of natural resources is caused by 'direct drivers of change' such as mining , petroleum extraction , fishing , and forestry as well as 'indirect drivers of change' such as demography (e.g. population growth), economy, society, politics, and technology. The current practice of agriculture

9702-437: The world, with official statistics claiming that 6,027 deaths occurred in 2004. To compare, 28 deaths were reported in the U.S. in the same year. Coal production in China is twice that in the US, while the number of coal miners is around 50 times that of the US, making deaths in coal mines in China 4 times as common per worker (108 times as common per unit output) as in the US. Mine disasters have still occurred in recent years in

9801-528: Was mined, and 375.1 million tonnes was exported. In 2013/14, coal provided about 69% of Australia's electricity production. In 2013, Australia was the world's fifth-largest coal producer, after China, the United States, India, and Indonesia. However, in terms of proportion of production exported, Australia is the world's second largest coal exporter, as it exports roughly 73% of its coal production. Indonesia exports about 87% of its coal production. A court in Australia has cited climate change in ruling against

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