117-563: The Bude Canal was a canal built to serve the hilly hinterland in the Cornwall and Devon border territory in the United Kingdom , chiefly to bring lime-bearing sand for agricultural fertiliser. The Bude Canal system was one of the most unusual in Britain. It was remarkable in using inclined planes to haul tub boats on wheels to the upper levels. There were only two conventional locks , in
234-534: A caisson of water in which boats float while being moved between two levels; and inclined planes where a caisson is hauled up a steep railway. To cross a stream, road or valley (where the delay caused by a flight of locks at either side would be unacceptable) the valley can be spanned by a navigable aqueduct – a famous example in Wales is the Pontcysyllte Aqueduct (now a UNESCO World Heritage Site ) across
351-512: A cyclothem . Cyclothems are thought to have their origin in glacial cycles that produced fluctuations in sea level , which alternately exposed and then flooded large areas of continental shelf. The woody tissue of plants is composed mainly of cellulose, hemicellulose, and lignin. Modern peat is mostly lignin, with a content of cellulose and hemicellulose ranging from 5% to 40%. Various other organic compounds, such as waxes and nitrogen- and sulfur-containing compounds, are also present. Lignin has
468-504: A drainage divide atop a ridge , generally requiring an external water source above the highest elevation . The best-known example of such a canal is the Panama Canal . Many canals have been built at elevations, above valleys and other waterways. Canals with sources of water at a higher level can deliver water to a destination such as a city where water is needed. The Roman Empire 's aqueducts were such water supply canals. The term
585-415: A "cistern", or depressed area just downstream from the fall, to "cushion" the water by providing a deep pool for its kinetic energy to be diffused in. Vertical falls work for drops of up to 1.5 m in height, and for discharge of up to 15 cubic meters per second. The transport capacity of pack animals and carts is limited. A mule can carry an eighth-ton [250 pounds (113 kg)] maximum load over
702-496: A canal has a series of dams and locks that create reservoirs of low speed current flow. These reservoirs are referred to as slack water levels , often just called levels . A canal can be called a navigation canal when it parallels a natural river and shares part of the latter's discharges and drainage basin , and leverages its resources by building dams and locks to increase and lengthen its stretches of slack water levels while staying in its valley . A canal can cut across
819-413: A combination of the three, depending on available water and available path: Smaller transportation canals can carry barges or narrowboats , while ship canals allow seagoing ships to travel to an inland port (e.g., Manchester Ship Canal ), or from one sea or ocean to another (e.g., Caledonian Canal , Panama Canal ). At their simplest, canals consist of a trench filled with water. Depending on
936-543: A journey measured in days and weeks, though much more for shorter distances and periods with appropriate rest. Besides, carts need roads. Transport over water is much more efficient and cost-effective for large cargoes. The oldest known canals were irrigation canals, built in Mesopotamia c. 4000 BC , in what is now Iraq . The Indus Valley civilization of ancient India ( c. 3000 BC ) had sophisticated irrigation and storage systems developed, including
1053-417: A process called carbonization . Carbonization proceeds primarily by dehydration , decarboxylation , and demethanation. Dehydration removes water molecules from the maturing coal via reactions such as Decarboxylation removes carbon dioxide from the maturing coal: while demethanation proceeds by reaction such as In these formulas, R represents the remainder of a cellulose or lignin molecule to which
1170-575: A rather low gradient for its time. The canal is still in use after renovation. In the Middle Ages , water transport was several times cheaper and faster than transport overland. Overland transport by animal drawn conveyances was used around settled areas, but unimproved roads required pack animal trains, usually of mules to carry any degree of mass, and while a mule could carry an eighth ton, it also needed teamsters to tend it and one man could only tend perhaps five mules, meaning overland bulk transport
1287-720: A single day. Main line Bude to Launceston Holsworthy Branch Feeder from Lower Tamar Lake Download coordinates as: Route details extracted from 1885 OS maps. [REDACTED] Media related to Bude Canal at Wikimedia Commons 50°49′39″N 4°32′52″W / 50.8275°N 4.5479°W / 50.8275; -4.5479 Canal Canals or artificial waterways are waterways or engineered channels built for drainage management (e.g. flood control and irrigation ) or for conveyancing water transport vehicles (e.g. water taxi ). They carry free, calm surface flow under atmospheric pressure , and can be thought of as artificial rivers . In most cases,
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#17328514815991404-527: A switch in fuels happened in London in the late sixteenth and early seventeenth centuries. Historian Ruth Goodman has traced the socioeconomic effects of that switch and its later spread throughout Britain and suggested that its importance in shaping the industrial adoption of coal has been previously underappreciated. The development of the Industrial Revolution led to the large-scale use of coal, as
1521-549: A tenth. Indonesia and Australia export the most, followed by Russia . The word originally took the form col in Old English , from reconstructed Proto-Germanic * kula ( n ), from Proto-Indo-European root * g ( e ) u-lo- "live coal". Germanic cognates include the Old Frisian kole , Middle Dutch cole , Dutch kool , Old High German chol , German Kohle and Old Norse kol . Irish gual
1638-453: A uniform altitude. Other, generally later, canals took more direct routes requiring the use of various methods to deal with the change in level. Canals have various features to tackle the problem of water supply. In cases, like the Suez Canal, the canal is open to the sea. Where the canal is not at sea level, a number of approaches have been adopted. Taking water from existing rivers or springs
1755-453: A vertical interval of 5 feet 6 inches (1.68 m). This section terminated at Helebridge, about 2 miles (3.2 km) from Bude, and ordinary coastal barges travelled this far up the canal. The tub boats were designed to use the main part of the system, and they generally made the transit from the harbour at Bude, or from Helebridge if trans-shipping from coastal vessels there. After Helebridge, there were three inclined planes to
1872-403: A weight basis. This composition reflects partly the composition of the precursor plants. The second main fraction of coal is ash, an undesirable, noncombustable mixture of inorganic minerals. The composition of ash is often discussed in terms of oxides obtained after combustion in air: Of particular interest is the sulfur content of coal, which can vary from less than 1% to as much as 4%. Most of
1989-406: A weight composition of about 54% carbon, 6% hydrogen, and 30% oxygen, while cellulose has a weight composition of about 44% carbon, 6% hydrogen, and 49% oxygen. Bituminous coal has a composition of about 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis. The low oxygen content of coal shows that coalification removed most of the oxygen and much of the hydrogen
2106-1043: A weight of about fifteen tons was necessary. This was successful, and the bucket raised a boat up the plane in about four minutes, which was about one half of the time taken when the 16 horsepower (12 kW) standby steam engine was used. 50°48′56″N 4°29′43″W / 50.815446°N 4.495159°W / 50.815446; -4.495159 ( Hobbacott inclined plane ) 50°50′03″N 4°26′13″W / 50.834145°N 4.43689°W / 50.834145; -4.43689 ( Vealand inclined plane ) 50°47′20″N 4°27′15″W / 50.789022°N 4.454294°W / 50.789022; -4.454294 ( Merrifield inclined plane ) 50°44′10″N 4°22′32″W / 50.736075°N 4.37557°W / 50.736075; -4.37557 ( Tamerton inclined plane ) 50°41′23″N 4°21′11″W / 50.689654°N 4.353077°W / 50.689654; -4.353077 ( Bridgetown inclined plane ) The gradients of
2223-422: Is a channel that cuts across a drainage divide , making a navigable channel connecting two different drainage basins . Both navigations and canals use engineered structures to improve navigation: Since they cut across drainage divides, canals are more difficult to construct and often need additional improvements, like viaducts and aqueducts to bridge waters over streams and roads, and ways to keep water in
2340-625: Is also a cognate via the Indo-European root. The conversion of dead vegetation into coal is called coalification . At various times in the geologic past, the Earth had dense forests in low-lying areas. In these wetlands, the process of coalification began when dead plant matter was protected from oxidation , usually by mud or acidic water, and was converted into peat . The resulting peat bogs , which trapped immense amounts of carbon, were eventually deeply buried by sediments. Then, over millions of years,
2457-429: Is burned in a turbine). Hot exhaust gases from the turbine are used to raise steam in a heat recovery steam generator which powers a supplemental steam turbine . The overall plant efficiency when used to provide combined heat and power can reach as much as 94%. IGCC power plants emit less local pollution than conventional pulverized coal-fueled plants. Other ways to use coal are as coal-water slurry fuel (CWS), which
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#17328514815992574-594: Is entirely vertical; however, metamorphism may cause lateral changes of rank, irrespective of depth. For example, some of the coal seams of the Madrid, New Mexico coal field were partially converted to anthracite by contact metamorphism from an igneous sill while the remainder of the seams remained as bituminous coal. The earliest recognized use is from the Shenyang area of China where by 4000 BC Neolithic inhabitants had begun carving ornaments from black lignite. Coal from
2691-455: Is made when metallurgical coal (also known as coking coal ) is baked in an oven without oxygen at temperatures as high as 1,000 °C, driving off the volatile constituents and fusing together the fixed carbon and residual ash. Metallurgical coke is used as a fuel and as a reducing agent in smelting iron ore in a blast furnace . The carbon monoxide produced by its combustion reduces hematite (an iron oxide ) to iron. Pig iron , which
2808-409: Is more abundant, and anthracite. The % carbon in coal follows the order anthracite > bituminous > lignite > brown coal. The fuel value of coal varies in the same order. Some anthracite deposits contain pure carbon in the form of graphite . For bituminous coal, the elemental composition on a dry, ash-free basis of 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on
2925-432: Is mostly carbon with variable amounts of other elements , chiefly hydrogen , sulfur , oxygen , and nitrogen . Coal is a type of fossil fuel , formed when dead plant matter decays into peat which is converted into coal by the heat and pressure of deep burial over millions of years. Vast deposits of coal originate in former wetlands called coal forests that covered much of the Earth's tropical land areas during
3042-675: Is presumed, introduced in Italy by Bertola da Novate in the 16th century. This allowed wider gates and also removed the height restriction of guillotine locks . To break out of the limitations caused by river valleys, the first summit level canals were developed with the Grand Canal of China in 581–617 AD whilst in Europe the first, also using single locks, was the Stecknitz Canal in Germany in 1398. In
3159-578: Is rarely less than 30 metres (98 ft) wide. In the 5th century BC, Achaemenid king Xerxes I of Persia ordered the construction of the Xerxes Canal through the base of Mount Athos peninsula, Chalkidiki , northern Greece. It was constructed as part of his preparations for the Second Persian invasion of Greece , a part of the Greco-Persian Wars . It is one of the few monuments left by
3276-418: Is steeper than the desired canal gradient. They are constructed so the falling water's kinetic energy is dissipated in order to prevent it from scouring the bed and sides of the canal. A canal fall is constructed by cut and fill . It may be combined with a regulator, bridge, or other structure to save costs. There are various types of canal falls, based on their shape. One type is the ogee fall, where
3393-448: Is the pound lock , which consists of a chamber within which the water level can be raised or lowered connecting either two pieces of canal at a different level or the canal with a river or the sea. When there is a hill to be climbed, flights of many locks in short succession may be used. Prior to the development of the pound lock in 984 AD in China by Chhaio Wei-Yo and later in Europe in
3510-452: Is used as fuel. 27.6% of world energy was supplied by coal in 2017 and Asia used almost three-quarters of it. Other large-scale applications also exist. The energy density of coal is roughly 24 megajoules per kilogram (approximately 6.7 kilowatt-hours per kg). For a coal power plant with a 40% efficiency, it takes an estimated 325 kg (717 lb) of coal to power a 100 W lightbulb for one year. In 2022, 68% of global coal use
3627-636: The Bude Canal Act 1774 ( 14 Geo. 3 . c. 53), but financial problems and the Napoleonic Wars frustrated the proposal. In 1818, the West Country canal engineer James Green produced a report for canal's backers, and an act of Parliament , the Bude Harbour and Canal Act 1819 ( 59 Geo. 3 . c. lv), was obtained for this more moderate proposal in 1819. After some difficulties in the construction phase,
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3744-691: The Bronze Age (3000–2000 BC), where it formed part of funeral pyres . In Roman Britain , with the exception of two modern fields, "the Romans were exploiting coals in all the major coalfields in England and Wales by the end of the second century AD". Evidence of trade in coal, dated to about AD 200, has been found at the Roman settlement at Heronbridge , near Chester ; and in the Fenlands of East Anglia , where coal from
3861-639: The Elbe , Oder and Weser being linked by canals. In post-Roman Britain, the first early modern period canal built appears to have been the Exeter Canal , which was surveyed in 1563, and open in 1566. The oldest canal in the European settlements of North America, technically a mill race built for industrial purposes, is Mother Brook between the Boston, Massachusetts neighbourhoods of Dedham and Hyde Park connecting
3978-512: The Fushun mine in northeastern China was used to smelt copper as early as 1000 BC. Marco Polo , the Italian who traveled to China in the 13th century, described coal as "black stones ... which burn like logs", and said coal was so plentiful, people could take three hot baths a week. In Europe, the earliest reference to the use of coal as fuel is from the geological treatise On Stones (Lap. 16) by
4095-590: The Midlands was transported via the Car Dyke for use in drying grain. Coal cinders have been found in the hearths of villas and Roman forts , particularly in Northumberland , dated to around AD 400. In the west of England, contemporary writers described the wonder of a permanent brazier of coal on the altar of Minerva at Aquae Sulis (modern day Bath ), although in fact easily accessible surface coal from what became
4212-530: The Naviglio Grande built between 1127 and 1257 to connect Milan with the river Ticino . The Naviglio Grande is the most important of the lombard " navigli " and the oldest functioning canal in Europe. Later, canals were built in the Netherlands and Flanders to drain the polders and assist transportation of goods and people. Canal building was revived in this age because of commercial expansion from
4329-532: The Phoenix metropolitan area was the most complex in ancient North America. A portion of the ancient canals has been renovated for the Salt River Project and now helps to supply the city's water. The Sinhalese constructed the 87 km (54 mi) Yodha Ela in 459 A.D. as a part of their extensive irrigation network which functioned in a way of a moving reservoir due to its single banking aspect to manage
4446-522: The River Brue at Northover with Glastonbury Abbey , a distance of about 1.75 kilometres (1,900 yd). Its initial purpose is believed to be the transport of building stone for the abbey, but later it was used for delivering produce, including grain, wine and fish, from the abbey's outlying properties. It remained in use until at least the 14th century, but possibly as late as the mid-16th century. More lasting and of more economic impact were canals like
4563-652: The Somerset coalfield was in common use in quite lowly dwellings locally. Evidence of coal's use for iron -working in the city during the Roman period has been found. In Eschweiler , Rhineland , deposits of bituminous coal were used by the Romans for the smelting of iron ore . No evidence exists of coal being of great importance in Britain before about AD 1000, the High Middle Ages . Coal came to be referred to as "seacoal" in
4680-594: The Songhai Empire of West Africa, several canals were constructed under Sunni Ali and Askia Muhammad I between Kabara and Timbuktu in the 15th century. These were used primarily for irrigation and transport. Sunni Ali also attempted to construct a canal from the Niger River to Walata to facilitate conquest of the city but his progress was halted when he went to war with the Mossi Kingdoms . Around 1500–1800
4797-491: The coal gap in the Permian–Triassic extinction event , where coal is rare. Favorable geography alone does not explain the extensive Carboniferous coal beds. Other factors contributing to rapid coal deposition were high oxygen levels, above 30%, that promoted intense wildfires and formation of charcoal that was all but indigestible by decomposing organisms; high carbon dioxide levels that promoted plant growth; and
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4914-478: The inclined planes by chains, which were operated in most cases by waterwheels ; the transit took five minutes or so. There were standby steam engines at some of the inclined planes. However the Hobbacott Inclined Plane (both the steepest and that allowing the greatest height difference) used a different system of harnessing water power: water filled a very large bucket, and it was simply the weight of
5031-548: The reservoirs built at Girnar in 3000 BC. This is the first time that such planned civil project had taken place in the ancient world. In Egypt , canals date back at least to the time of Pepi I Meryre (reigned 2332–2283 BC), who ordered a canal built to bypass the cataract on the Nile near Aswan . In ancient China , large canals for river transport were established as far back as the Spring and Autumn period (8th–5th centuries BC),
5148-444: The steam engine took over from the water wheel . In 1700, five-sixths of the world's coal was mined in Britain. Britain would have run out of suitable sites for watermills by the 1830s if coal had not been available as a source of energy. In 1947 there were some 750,000 miners in Britain, but the last deep coal mine in the UK closed in 2015. A grade between bituminous coal and anthracite
5265-404: The stratum the canal passes through, it may be necessary to line the cut with some form of watertight material such as clay or concrete. When this is done with clay, it is known as puddling . Canals need to be level, and while small irregularities in the lie of the land can be dealt with through cuttings and embankments, for larger deviations other approaches have been adopted. The most common
5382-466: The 12th century. River navigations were improved progressively by the use of single, or flash locks . Taking boats through these used large amounts of water leading to conflicts with watermill owners and to correct this, the pound or chamber lock first appeared, in the 10th century in China and in Europe in 1373 in Vreeswijk , Netherlands. Another important development was the mitre gate , which was, it
5499-407: The 13th century; the wharf where the material arrived in London was known as Seacoal Lane, so identified in a charter of King Henry III granted in 1253. Initially, the name was given because much coal was found on the shore, having fallen from the exposed coal seams on cliffs above or washed out of underwater coal outcrops, but by the time of Henry VIII , it was understood to derive from the way it
5616-465: The 15th century, either flash locks consisting of a single gate were used or ramps, sometimes equipped with rollers, were used to change the level. Flash locks were only practical where there was plenty of water available. Locks use a lot of water, so builders have adopted other approaches for situations where little water is available. These include boat lifts , such as the Falkirk Wheel , which use
5733-578: The Carboniferous, and suggested that climatic and tectonic factors were a more plausible explanation, reconstruction of ancestral enzymes by phylogenetic analysis corroborated a hypothesis that lignin degrading enzymes appeared in fungi approximately 200 MYa. One likely tectonic factor was the Central Pangean Mountains , an enormous range running along the equator that reached its greatest elevation near this time. Climate modeling suggests that
5850-587: The Central Pangean Mountains contributed to the deposition of vast quantities of coal in the late Carboniferous. The mountains created an area of year-round heavy precipitation, with no dry season typical of a monsoon climate. This is necessary for the preservation of peat in coal swamps. Coal is known from Precambrian strata, which predate land plants. This coal is presumed to have originated from residues of algae. Sometimes coal seams (also known as coal beds) are interbedded with other sediments in
5967-563: The Greek scientist Theophrastus (c. 371–287 BC): Among the materials that are dug because they are useful, those known as anthrakes [coals] are made of earth, and, once set on fire, they burn like charcoal [anthrakes]. They are found in Liguria ;... and in Elis as one approaches Olympia by the mountain road; and they are used by those who work in metals. Outcrop coal was used in Britain during
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#17328514815996084-582: The Holsworthy branch being abandoned, but the Feeder arm continuing to be kept open because of the water rights. After protracted negotiations, the remainder of the canal was bought by Stratton and Bude Urban District Council, on 1 January 1902, and this enabled them to supply domestic water in due course to the villages in the district from the canal's Tamar reservoir. The works became the responsibility of North Cornwall District Council [1] when English local government
6201-571: The Persian Empire in Europe . Greek engineers were also among the first to use canal locks , by which they regulated the water flow in the Ancient Suez Canal as early as the 3rd century BC. There was little experience moving bulk loads by carts, while a pack-horse would [i.e. 'could'] carry only an eighth of a ton. On a soft road a horse might be able to draw 5/8ths of a ton. But if
6318-753: The Southwest by 1300 CE. Archaeologists working at a major archaeological dig in the 1990s in the Tucson Basin, along the Santa Cruz River, identified a culture and people that may have been the ancestors of the Hohokam. This prehistoric group occupied southern Arizona as early as 2000 BCE, and in the Early Agricultural period grew corn, lived year-round in sedentary villages, and developed sophisticated irrigation canals. The large-scale Hohokam irrigation network in
6435-416: The basin. During the course of the dredging, over 6,000 cubic metres (7,800 cu yd) of silt were removed. It was originally intended to refill the basin gradually after 8 July 2008, but a period of intense rainfall prior to that date resulted in a surge of water passing down the canal, which damaged the coffer dam protecting the empty section from the watered section. Consequently, the basin refilled in
6552-474: The canal outright to the railway company, or anyone else. However, legal conditions agreed at the time of construction gave certain landowners rights to take water from the canal, and they would not give up these rights without compensation, so for the time being the proposals for disposal were frustrated. Finally, abandonment of the tub boat operation took place on 14 November 1891, with the Launceston main line and
6669-436: The canal pressure with the influx of water. It was also designed as an elongated reservoir passing through traps creating 66 mini catchments as it flows from Kala Wewa to Thissa Wawa . The canal was not designed for the quick conveying of water from Kala Wewa to Thissa Wawa but to create a mass of water between the two reservoirs, which would in turn provided for agriculture and the use of humans and animals. They also achieved
6786-418: The canal to form a dam. They are generally placed in pre-existing grooves in the canal bank. On more modern canals, "guard locks" or gates were sometimes placed to allow a section of the canal to be quickly closed off, either for maintenance, or to prevent a major loss of water due to a canal breach. A canal fall , or canal drop, is a vertical drop in the canal bed. These are built when the natural ground slope
6903-429: The canal was completed, and opened on 8 July 1823. Its cost was £118,000. The project: The main line of the canal ran south east from Bude to Druxton Wharf near Launceston , with an easterly branch to Blagdonmoor , beyond Holsworthy . There was a northerly feeder arm leading from a new reservoir at Virworthy, now called Lower Tamar Lake . There were two conventional locks in the short broad canal section, each with
7020-468: The canal's boating history. On Monday 10 March 2008, a powerful storm wrenched one of the lock gates off its fixings. Contractors removed the gate the following morning, and four-tonne concrete pipes were placed in the canal basin to dissipate the power of waves coming in from the sea. A temporary dam was constructed at Falcon Bridge, and a team of anglers and staff from the Environment Agency rescued
7137-455: The canal's presence, in bridges and wharf buildings. On the feeder branch and on the lower part of the Launceston main line, the alignment is indicated on current Ordnance Survey maps. In most cases, the alignment is not open to the public, however. An exhaustive list of locations where the canal's remains can be seen may be found in Harris and Ellis. In 2005 major plans were approved to re-develop
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#17328514815997254-554: The canal, including renewal of the two locks between the sea lock and the first inclined plane . £3.8 million in funding for this project was provided by the Heritage Lottery Fund , Objective One and the South West Regional Development Agency. Most of the planned projects were completed by 31 March 2009, which was also the date on which North Cornwall District Council ceased to exist: the partners in
7371-462: The canal. Where large amounts of goods are loaded or unloaded such as at the end of a canal, a canal basin may be built. This would normally be a section of water wider than the general canal. In some cases, the canal basins contain wharfs and cranes to assist with movement of goods. When a section of the canal needs to be sealed off so it can be drained for maintenance stop planks are frequently used. These consist of planks of wood placed across
7488-463: The channel. There are two broad types of canal: Historically, canals were of immense importance to commerce and the development, growth and vitality of a civilization. In 1855 the Lehigh Canal carried over 1.2 million tons of anthracite coal; by the 1930s the company which built and operated it for over a century ceased operation. The few canals still in operation in our modern age are a fraction of
7605-399: The drop follows an s-shaped curve to create a smooth transition and reduce turbulence . However, this smooth transition does not dissipate the water's kinetic energy, which leads to heavy scouring. As a result, the canal needs to be reinforced with concrete or masonry to protect it from eroding. Another type of canal fall is the vertical fall, which is "simple and economical". These feature
7722-571: The environment , causing premature death and illness, and it is the largest anthropogenic source of carbon dioxide contributing to climate change . Fourteen billion tonnes of carbon dioxide were emitted by burning coal in 2020, which is 40% of total fossil fuel emissions and over 25% of total global greenhouse gas emissions . As part of worldwide energy transition , many countries have reduced or eliminated their use of coal power . The United Nations Secretary General asked governments to stop building new coal plants by 2020. Global coal use
7839-430: The evolution of the first trees . But bacteria and fungi did not immediately evolve the ability to decompose lignin, so the wood did not fully decay but became buried under sediment, eventually turning into coal. About 300 million years ago, mushrooms and other fungi developed this ability, ending the main coal-formation period of earth's history. Although some authors pointed at some evidence of lignin degradation during
7956-512: The factors involved in coalification, temperature is much more important than either pressure or time of burial. Subbituminous coal can form at temperatures as low as 35 to 80 °C (95 to 176 °F) while anthracite requires a temperature of at least 180 to 245 °C (356 to 473 °F). Although coal is known from most geologic periods , 90% of all coal beds were deposited in the Carboniferous and Permian periods. Paradoxically, this
8073-648: The first summit level canal to use pound locks in Europe was the Briare Canal connecting the Loire and Seine (1642), followed by the more ambitious Canal du Midi (1683) connecting the Atlantic to the Mediterranean. This included a staircase of 8 locks at Béziers , a 157 metres (515 ft) tunnel, and three major aqueducts. Canal building progressed steadily in Germany in the 17th and 18th centuries with three great rivers,
8190-414: The fish population before it was swept out to sea. Beyond the dam, the loss of water was contained, with levels only dropping by about 8 inches (20 cm), but at the lower end of the canal water continued to flow out until it was practically empty, revealing some interesting finds in the mud, including a shotgun. The North Cornwall District Council used the opportunity to repair the canal walls and dredge
8307-498: The form of iron pyrite (FeS 2 ). Being a dense mineral, it can be removed from coal by mechanical means, e.g. by froth flotation . Some sulfate occurs in coal, especially weathered samples. It is not volatilized and can be removed by washing. Minor components include: As minerals, Hg, As, and Se are not problematic to the environment, especially since they are only trace components. They become however mobile (volatile or water-soluble) when these minerals are combusted. Most coal
8424-456: The freedom to make deliveries well away from rail lined road beds or ditches in the dirt which could not operate in the winter. The longest extant canal today, the Grand Canal in northern China, still remains in heavy use, especially the portion south of the Yellow River . It stretches from Beijing to Hangzhou at 1,794 kilometres (1,115 miles). Canals are built in one of three ways, or
8541-475: The heat and pressure of deep burial caused the loss of water, methane and carbon dioxide and increased the proportion of carbon. The grade of coal produced depended on the maximum pressure and temperature reached, with lignite (also called "brown coal") produced under relatively mild conditions, and sub-bituminous coal , bituminous coal , or anthracite coal (also called "hard coal" or "black coal") produced in turn with increasing temperature and pressure. Of
8658-729: The higher waters of the Charles River and the mouth of the Neponset River and the sea. It was constructed in 1639 to provide water power for mills. In Russia, the Volga–Baltic Waterway , a nationwide canal system connecting the Baltic Sea and Caspian Sea via the Neva and Volga rivers, was opened in 1718. Coal Coal is a combustible black or brownish-black sedimentary rock , formed as rock strata called coal seams . Coal
8775-431: The increasing tendency of the anthracite to break with a conchoidal fracture , similar to the way thick glass breaks. As geological processes apply pressure to dead biotic material over time, under suitable conditions, its metamorphic grade or rank increases successively into: There are several international standards for coal. The classification of coal is generally based on the content of volatiles . However
8892-518: The late Carboniferous ( Pennsylvanian ) and Permian times. Coal is used primarily as a fuel. While coal has been known and used for thousands of years, its usage was limited until the Industrial Revolution . With the invention of the steam engine , coal consumption increased. In 2020, coal supplied about a quarter of the world's primary energy and over a third of its electricity . Some iron and steel -making and other industrial processes burn coal. The extraction and burning of coal damages
9009-535: The load were carried by a barge on a waterway, then up to 30 tons could be drawn by the same horse. — technology historian Ronald W. Clark referring to transport realities before the industrial revolution and the Canal age . Hohokam was a society in the North American Southwest in what is now part of Arizona , United States, and Sonora , Mexico. Their irrigation systems supported the largest population in
9126-472: The longest canal in the world today and the oldest extant one. It is 1,794 kilometres (1,115 mi) long and was built to carry the Emperor Yang Guang between Zhuodu ( Beijing ) and Yuhang ( Hangzhou ). The project began in 605 and was completed in 609, although much of the work combined older canals, the oldest section of the canal existing since at least 486 BC. Even in its narrowest urban sections it
9243-523: The longest one of that period being the Hong Gou (Canal of the Wild Geese), which according to the ancient historian Sima Qian connected the old states of Song, Zhang, Chen, Cai, Cao, and Wei. The Caoyun System of canals was essential for imperial taxation, which was largely assessed in kind and involved enormous shipments of rice and other grains. By far the longest canal was the Grand Canal of China , still
9360-491: The main watercourse and its valley. The unusual feature of the canal was the six inclined planes . The tub boats had wheels, and on the inclined planes they were pulled up the slopes with the wheels running in channel rails (like a squat letter "U" in section). There were two sets of rails, one for each direction, but it does not appear that a counterbalancing system was used (in which a boat coming down would balance one being pulled up). The tub boats were hauled up and let down
9477-498: The mile or so between the wharf and the railway station must have been negotiated by horse and cart. Nonetheless, the arrival of the railway soon spelt the ultimate doom of the canal: manufactured fertilisers had become commonplace and cheap, and they could be brought in by railway, so that the demand for the local sand was diminished considerably. When it became obvious that the canal could not survive, some directors proposed obtaining parliamentary authority for abandonment, or selling
9594-453: The morphology and some properties of the original plant. In many coals, individual macerals can be identified visually. Some macerals include: In coalification huminite is replaced by vitreous (shiny) vitrinite . Maturation of bituminous coal is characterized by bitumenization , in which part of the coal is converted to bitumen , a hydrocarbon-rich gel. Maturation to anthracite is characterized by debitumenization (from demethanation) and
9711-405: The most important distinction is between thermal coal (also known as steam coal), which is burnt to generate electricity via steam; and metallurgical coal (also known as coking coal), which is burnt at high temperature to make steel . Hilt's law is a geological observation that (within a small area) the deeper the coal is found, the higher its rank (or grade). It applies if the thermal gradient
9828-407: The nature of Carboniferous forests, which included lycophyte trees whose determinate growth meant that carbon was not tied up in heartwood of living trees for long periods. One theory suggested that about 360 million years ago, some plants evolved the ability to produce lignin , a complex polymer that made their cellulose stems much harder and more woody. The ability to produce lignin led to
9945-455: The number of double bonds between carbon). As carbonization proceeds, aliphatic compounds convert to aromatic compounds . Similarly, aromatic rings fuse into polyaromatic compounds (linked rings of carbon atoms). The structure increasingly resembles graphene , the structural element of graphite. Chemical changes are accompanied by physical changes, such as decrease in average pore size. The macerals are coalified plant parts that retain
10062-506: The numbers that once fueled and enabled economic growth, indeed were practically a prerequisite to further urbanization and industrialization. For the movement of bulk raw materials such as coal and ores are difficult and marginally affordable without water transport. Such raw materials fueled the industrial developments and new metallurgy resulting of the spiral of increasing mechanization during 17th–20th century, leading to new research disciplines, new industries and economies of scale, raising
10179-546: The planes differed somewhat, with Hobbacott being the steepest at 1 in 4.5 and Vealand being the gentlest at 1 in 8.6. The tub boats were 20 feet (6.1 m) long and 5 feet 6 inches (1.68 m) wide, and carried about 20 tons payload; the usage of tub boats was not confined to the Bude Canal. They were commonly operated by coupling between 4 and 6 together and hauling them – by horse power – together. A "train" of boats could therefore be 120 feet (37 m) long, and on
10296-456: The pre-combustion treatment, turbine technology (e.g. supercritical steam generator ) and the age of the plant. A few integrated gasification combined cycle (IGCC) power plants have been built, which burn coal more efficiently. Instead of pulverizing the coal and burning it directly as fuel in the steam-generating boiler, the coal is gasified to create syngas , which is burned in a gas turbine to produce electricity (just like natural gas
10413-582: The pre-railroad days of the industrial revolution, water transport was the gold standard of fast transportation. The first artificial canal in Western Europe was the Fossa Carolina built at the end of the 8th century under personal supervision of Charlemagne . In Britain, the Glastonbury Canal is believed to be the first post-Roman canal and was built in the middle of the 10th century to link
10530-421: The project expressed the hope that the new Unitary Authority would complete the three unfinished elements: raising Rodd's bridge, providing slipways at each end of the canal, and re-connecting it to Helebridge Wharf. One element of the restoration was a number of wooden sculptures by Daniel Sodhi-Miles. These are inscribed with Cornish words and phrases, and take the form of chains or parts of chains, recalling
10647-419: The rails, at transfer from canal to plane, must have been difficult. Once engaged with the continuous chain, it would have been impracticable to stop the motion momentarily while the wheels were guided to the rail channels; but no record is available as to how this was achieved. On completion of the canal, the owning company was constantly short of cash, and inevitably income did not reach the levels predicted at
10764-427: The reacting groups are attached. Dehydration and decarboxylation take place early in coalification, while demethanation begins only after the coal has already reached bituminous rank. The effect of decarboxylation is to reduce the percentage of oxygen, while demethanation reduces the percentage of hydrogen. Dehydration does both, and (together with demethanation) reduces the saturation of the carbon backbone (increasing
10881-500: The sand. In the pre-industrial age, actually transporting it was difficult, even to land relatively close to the coast. Several schemes were put forward for canals to bring the sand to the countryside, and these proposals did not lack ambition. One early scheme, conceived by Cornish engineer John Edyvean , aimed at distributing Welsh coal from the port as far inland as Calstock on the River Tamar . It gained approval for construction in
10998-466: The short broad canal section near the sea at Bude itself. It had a total extent of 35 miles (56 km), and it rose from sea level to an altitude of 433 feet (132 m). The design of the canal influenced the design of the Rolle Canal . The coastal area at Bude has sand unusually rich in minerals, and the poor agricultural land of the locality was found to benefit considerably from application of
11115-452: The stage of promoting the canal. In addition, serious problems with the state of the newly finished works were discovered, although in the circumstances of a locally promoted scheme with novel technological aspects, the canal as built was better engineered than it might have been. The chains on the inclined planes were constantly breaking, the rails broke, and other mechanical failures were frequent, and physical damage from careless boat handling
11232-480: The standard of living for any industrialized society. Most ship canals today primarily service bulk cargo and large ship transportation industries, whereas the once critical smaller inland waterways conceived and engineered as boat and barge canals have largely been supplanted and filled in, abandoned and left to deteriorate, or kept in service and staffed by state employees, where dams and locks are maintained for flood control or pleasure boating. Their replacement
11349-399: The sulfur and most of the nitrogen is incorporated into the organic fraction in the form of organosulfur compounds and organonitrogen compounds . This sulfur and nitrogen are strongly bound within the hydrocarbon matrix. These elements are released as SO 2 and NO x upon combustion. They cannot be removed, economically at least, otherwise. Some coals contain inorganic sulfur, mainly in
11466-645: The summit section; the whole of the central part of the system was at this level, 433 feet (132 m) above sea level. The main line to Druxton Wharf, near Launceston, negotiated three descending inclined planes as it followed the southerly course of the River Tamar. With no intermediate locks on the tub boat sections, the canal had to follow the contours between the inclined planes, and this made its route even more circuitous than most canals. However, some relatively ambitious viaducts and earthworks were constructed, particularly where side streams and small valleys entered
11583-556: The valley of the River Dee . Another option for dealing with hills is to tunnel through them. An example of this approach is the Harecastle Tunnel on the Trent and Mersey Canal . Tunnels are only practical for smaller canals. Some canals attempted to keep changes in level down to a minimum. These canals known as contour canals would take longer, winding routes, along which the land was
11700-399: The very sinuous alignment of the canal, the train must have been difficult to pass round sharp curves. Steering was possible by manually altering the connection between adjacent boats, using handspikes. Each boat had four wheels 14 inches (360 mm) in diameter for running on the inclined planes; the boats were hauled up and down individually. The operation of lining the tub boats up with
11817-464: The water that pulled the ascending tub boat up the incline. The bucket operated in a deep vertical shaft, and at the bottom a plug was opened and the water ran to waste along an adit which connected to the lower level of the canal; the descending bucket pulled an empty bucket up in the same operation. The full bucket had to be heavy enough to pull a loaded tub boat up the 1 in 4 1 ⁄ 2 gradient as well as overcoming friction, and Green calculated that
11934-415: The world's coal-generated electricity. Efforts around the world to reduce the use of coal have led some regions to switch to natural gas and renewable energy . In 2018 coal-fired power station capacity factor averaged 51%, that is they operated for about half their available operating hours. Coke is a solid carbonaceous residue that is used in manufacturing steel and other iron-containing products. Coke
12051-574: Was 8.3 billion tonnes in 2022, and is set to remain at record levels in 2023. To meet the Paris Agreement target of keeping global warming below 2 °C (3.6 °F) coal use needs to halve from 2020 to 2030, and "phasing down" coal was agreed upon in the Glasgow Climate Pact . The largest consumer and importer of coal in 2020 was China , which accounts for almost half the world's annual coal production, followed by India with about
12168-453: Was also common. However, the rich sand was successfully carried to farms near the various wharves in large quantities, and other merchandise was also carried, particularly coal from South Wales . Traffic picked up in the 1880s, and when the London and South Western Railway reached Holsworthy , the canal carried significant volumes of the sand to Stanbury Wharf for onward conveyance by railway;
12285-466: Was also expensive, as men expect compensation in the form of wages, room and board. This was because long-haul roads were unpaved, more often than not too narrow for carts, much less wagons, and in poor condition, wending their way through forests, marshy or muddy quagmires as often as unimproved but dry footing. In that era, as today, greater cargoes, especially bulk goods and raw materials , could be transported by ship far more economically than by land; in
12402-458: Was an option in some cases, sometimes supplemented by other methods to deal with seasonal variations in flow. Where such sources were unavailable, reservoirs – either separate from the canal or built into its course – and back pumping were used to provide the required water. In other cases, water pumped from mines was used to feed the canal. In certain cases, extensive "feeder canals" were built to bring water from sources located far from
12519-574: Was based on the trading of this commodity. Coal continues to arrive on beaches around the world from both natural erosion of exposed coal seams and windswept spills from cargo ships. Many homes in such areas gather this coal as a significant, and sometimes primary, source of home heating fuel. Coal consists mainly of a black mixture of diverse organic compounds and polymers. Of course, several kinds of coals exist, with variable dark colors and variable compositions. Young coals (brown coal, lignite) are not black. The two main black coals are bituminous, which
12636-504: Was carried to London by sea. In 1257–1259, coal from Newcastle upon Tyne was shipped to London for the smiths and lime -burners building Westminster Abbey . Seacoal Lane and Newcastle Lane, where coal was unloaded at wharves along the River Fleet , still exist. These easily accessible sources had largely become exhausted (or could not meet the growing demand) by the 13th century, when underground extraction by shaft mining or adits
12753-602: Was developed in the Soviet Union , or in an MHD topping cycle . However these are not widely used due to lack of profit. In 2017 38% of the world's electricity came from coal, the same percentage as 30 years previously. In 2018 global installed capacity was 2 TW (of which 1TW is in China) which was 30% of total electricity generation capacity. The most dependent major country is South Africa, with over 80% of its electricity generated by coal; but China alone generates more than half of
12870-408: Was developed. The alternative name was "pitcoal", because it came from mines. Cooking and home heating with coal (in addition to firewood or instead of it) has been done in various times and places throughout human history, especially in times and places where ground-surface coal was available and firewood was scarce, but a widespread reliance on coal for home hearths probably never existed until such
12987-490: Was during the Late Paleozoic icehouse , a time of global glaciation . However, the drop in global sea level accompanying the glaciation exposed continental shelves that had previously been submerged, and to these were added wide river deltas produced by increased erosion due to the drop in base level . These widespread areas of wetlands provided ideal conditions for coal formation. The rapid formation of coal ended with
13104-463: Was gradual, beginning first in the United States in the mid-1850s where canal shipping was first augmented by, then began being replaced by using much faster , less geographically constrained & limited, and generally cheaper to maintain railways . By the early 1880s, canals which had little ability to economically compete with rail transport, were off the map. In the next couple of decades, coal
13221-424: Was increasingly diminished as the heating fuel of choice by oil, and growth of coal shipments leveled off. Later, after World War I when motor-trucks came into their own, the last small U.S. barge canals saw a steady decline in cargo ton-miles alongside many railways, the flexibility and steep slope climbing capability of lorries taking over cargo hauling increasingly as road networks were improved, and which also had
13338-550: Was once known as "steam coal" as it was widely used as a fuel for steam locomotives . In this specialized use, it is sometimes known as "sea coal" in the United States. Small "steam coal", also called dry small steam nuts (DSSN), was used as a fuel for domestic water heating . Coal played an important role in industry in the 19th and 20th century. The predecessor of the European Union , the European Coal and Steel Community ,
13455-426: Was once used to describe linear features seen on the surface of Mars , Martian canals , an optical illusion. A navigation is a series of channels that run roughly parallel to the valley and stream bed of an unimproved river. A navigation always shares the drainage basin of the river. A vessel uses the calm parts of the river itself as well as improvements, traversing the same changes in height. A true canal
13572-413: Was reorganised in 1974. Today the sea lock is still in working order, and the canal is 'in water' as far as the base of the first inclined plane. The sea lock, though, is the only lock on this section still in working order, so that navigation is not possible along the whole network. Much of the upper section has been ploughed over or has become overgrown, but it is possible to see many remaining signs of
13689-430: Was used for electricity generation. Coal burnt in coal power stations to generate electricity is called thermal coal . It is usually pulverized and then burned in a furnace with a boiler . The furnace heat converts boiler water to steam , which is then used to spin turbines which turn generators and create electricity. The thermodynamic efficiency of this process varies between about 25% and 50% depending on
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