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98-644: Freeminer is an ancient title given to coal or iron miners in the Forest of Dean , Gloucestershire , England , who have earned the right to mine personal plots, known as gales . For hundreds of years, mining of the Forest of Dean Coalfield and iron reserves has been regulated through a system of Freemining, with the Free Miner's Mine Law Court sitting at the Speech House from 1682. The earliest known existing copy of Dean Miners’ Laws and Privileges , known locally as

196-512: 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

294-567: A coal or iron mine within the said Hundred of St Briavels, shall be deemed and taken to be Free Miners." the Dean Forest (Mines) Act 1838. This qualification has recently been challenged on the grounds of sex discrimination and although legal opinion advised that the 1838 Act was not subject to Equal Rights legislation, the Forestry Commissioners who act as Gaveller of the Forest of Dean made

392-652: A colouring agent in Africa for over 200,000 years. Women of the Himba ethnic group in Namibia use a mix of ochre and animal fat for body decoration, to achieve a reddish skin colour. The ochre mixture is also applied to their hair after braiding. Men and women of the Maasai people in Kenya and Tanzania have also used ochre in the same way. In Ancient Egypt , yellow was associated with gold, which

490-483: A large collection of ochre samples from many sites across Australia. There are many words for ochre in Australian Aboriginal languages throughout Australia, including: The Māori people of New Zealand were found to be making extensive use of mineral ochre mixed with fish oil. Ochre was the predominant colouring agent used by Maori, and was used to paint their large waka taua (war canoe). Ochre prevented

588-433: A more lovely and perfect ochre pigment...And know that this ochre is a common pigment, particularly when working in fresco; that with other mixtures that, as i will explain to you, it is used for flesh colours, for drapery, for coloured mountains and buildings and hair and in general for many things. In early modern Malta, red ochre paint was commonly used on public buildings. The industrial process for making ochre pigment

686-582: A mouldable putty that hardened into handles. Earlier excavations at Le Moustier prevent conclusive identification of the archaeological culture and age, but the European Mousterian style of these tools suggests they are associated with Neanderthals during the late Middle Paleolithic , between 60,000 and 35,000 years before present. It is the earliest evidence of compound adhesive use in Europe. Pieces of ochre engraved with abstract designs have been found at

784-502: A practice was common to the Celts of the British Isles , bog iron being particularly abundant in the midlands of Ireland . Ochre has uses other than as paint: "tribal peoples alive today . . . use either as a way to treat animal skins or else as an insect repellent, to staunch bleeding, or as protection from the sun. Ochre may have been the first medicament." Red ochre has been used as

882-417: 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

980-518: A specific archaeological period in the Woodlands c.  1000 –400 BC. California Native Americans such as the Tongva and Chumash were also known to use red ochre as body paint. Researchers diving into dark submerged caves on Mexico's Yucatán Peninsula have found evidence of an ambitious mining operation starting 12,000 years ago and lasting two millennia for red ochre. In Newfoundland , red ochre

1078-527: 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

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1176-549: 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

1274-721: A third of its electricity . Some iron and steel -making and other industrial processes burn coal. The extraction and burning of coal damages 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

1372-513: A waxy waterproof coating on structures. The reddle was sold as a ready-made mixture to farmers and herders by travelling workers called reddlemen. In Classical antiquity , the finest red ochre came from a Greek colony on the Black Sea where the modern city of Sinop in Turkey is located. It was carefully regulated, expensive and marked by a special seal, and this colour was called sealed Sinope. Later

1470-403: 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

1568-406: 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

1666-515: A yellow colour. A range of other minerals may also be included in the mixture: When natural sienna and umber pigments are heated, they are dehydrated and some of the limonite is transformed into hematite, giving them more reddish colours, called burnt sienna and burnt umber. Ochres are non-toxic and can be used to make an oil paint that dries quickly and covers surfaces thoroughly. Modern ochre pigments often are made using synthetic iron oxide. Pigments which use natural ochre pigments indicate it with

1764-506: Is a combustible black or brownish-black sedimentary rock , formed as rock strata called coal seams . Coal 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

1862-625: 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,

1960-429: 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

2058-592: Is difficult to pinpoint an exact shade or hue of red that would be considered the traditional " fishing stage red". In the Bonavista Bay area one man maintained that seal oil mixed with the ochre gave the sails a purer red colour, while cod liver oil would give a "foxy" colour, browner in hue. During the Renaissance, yellow and red ochre pigments were widely used in painting panels and frescoes. The colours vary greatly from region to region, depending upon whether

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2156-594: 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

2254-458: Is highlighted by the great number of powders of this color found in the containers. The powders were probably used to give a hue to cheeks or to lips. Besides these uses as make-up powders, we can also assume a ritual use of ointments and powders containing cinnabar or ochre, applied to the face and the forehead during preparation rituals of the bodies. The discovery of red paint traces on bones and skulls suggests that these practices were common among

2352-455: 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

2450-409: 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

2548-488: Is particularly intensive: it is not unusual to find a layer of the cave floor impregnated with a purplish red to a depth of eight inches. The size of these ochre deposits raises a problem not yet solved. The colouring is so intense that practically all the loose ground seems to consist of ochre. One can imagine that the Aurignacians regularly painted their bodies red, dyed their animal skins, coated their weapons, and sprinkled

2646-580: Is the basis for Free Mining today and Freemining is administered by the Deputy Gaveller; a post established in Medieval times, recently held by Chartered mining engineer John Harvey MBE (retired March 2011), and succeeded by Daniel Howell. There are probably still around 150 Freeminers alive today, only one of which is female, although only a handful of collieries are still operating, due to the demanding nature and relatively high costs of small-scale extraction;

2744-824: Is thought that these privileges were granted as a reward for their endeavours. A plaque bearing the engraved coat of arms of the Freeminers is on the Greyndour tomb in the Clearwell Chapel in Newland church, and other important medieval and modern mining emblems are in the Freeminers Guild church of St. Michael in Abenhall . Towards the end of the 18th century, as the Industrial Revolution began to take hold, increasing demand for coal and iron led to conflicting mining interests and

2842-403: Is too rich in dissolved carbon, is also produced. Ochre The word ochre also describes clays coloured with iron oxide derived during the extraction of tin and copper . Ochre is a family of earth pigments, which includes yellow ochre, red ochre, purple ochre, sienna, and umber. The major ingredient of all the ochres is iron(III) oxide-hydroxide , known as limonite , which gives them

2940-452: 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

3038-446: The Book of Dennis , dates from 1610 but the copy itself contains references to much earlier origins. It also claims that Freemining rights were granted to Foresters by Edward I who, in so doing, also confirmed that such 'customes and franchises' had existed since 'tyme out of mynde'. Freeminers had been instrumental in recapturing Berwick-upon-Tweed several times (1296, 1305 and 1315) and it

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3136-691: 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

3234-512: 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

3332-590: 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

3430-566: The National Coal Board (NCB), but these remained under the Freemining system, with a royalty paid to the Freeminers, by the NCB, as a share of the minerals extracted. The last of the NCB deep mines closed in 1965. "All male persons born or hereafter to be born and abiding within the said Hundred of St Briavels , of the age of twenty one years and upwards, who shall have worked a year and a day in

3528-774: The Russian Revolution and the Spanish Civil War . Ochre also began to face growing competition from newly synthetic pigment industry. The quarries in Roussillon, Rustrel, the Mines of Bruoux closed one by one. Today, the last quarry in activity is in Gargas (Vaucluse) and belongs to the Société des Ocres de France. Ochre, both red and yellow, appear as tinctures in South African heraldry ;

3626-702: 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

3724-546: The Vaucluse department of Provence , in France. Thanks to the process invented by Astier and refined by his successors, ochre pigments from Vaucluse were exported across Europe and around the world. It was not only used for artists paints and house paints; it also became an important ingredient for the early rubber industry. Ochre from Vaucluse was an important French export until the mid-20th century, when major markets were lost due to

3822-591: The Western Desert , Kimberley and Arnhem Land regions, and occur in many archaeological sites. The practice of ochre painting has been prevalent among Aboriginal Australians for over 40,000 years. Pleistocene burials with red ochre date as early as 40,000 BP and ochre plays a role in expressing symbolic ideologies of the earliest arrivals to the continent. Ochre has been used for millennia by Aboriginal people for body decoration, sun protection , mortuary practices, cave painting, bark painting and other artwork, and

3920-465: The cave of Altamira in Spain ( c.  16,500 –15,000 BC). The cave of Lascaux has an image of a horse coloured with yellow ochre estimated to be 17,300 years old. Neolithic burials may have used red ochre pigments symbolically, either to represent a return to the earth or possibly as a form of ritual rebirth, in which the colour may symbolize blood and a hypothesized Great Goddess . The use of ochre

4018-491: 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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4116-698: The national coat of arms , adopted in 2000, includes red ochre , while (yellow) ochre appears in the arms of the University of Transkei . Ochre is also used as a symbol of Indigenous Australians , and appears on the Flag of the Northern Territory and on the flags of the Taungurung and Aṉangu people. A reddleman named Diggory Venn was prominently described in Thomas Hardy 's 1878 novel entitled The Return of

4214-444: 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

4312-407: 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

4410-475: The British fishing industry, where it was combined with oil and used to coat sails to protect them from seawater, giving them a reddish colour. The ochre was boiled in great caldrons, together with tar , tallow and oak bark , the last ingredient giving the name of barking yards to the places where the hot mixture was painted on to the sails, which were then hung up to dry. In 1894, a theft case provided insights into

4508-578: 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

4606-587: 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

4704-407: The Earth's tropical land areas during 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

4802-563: 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

4900-522: The Latin and Italian name sinopia was given to wide range of dark red ochre pigments. Roman triumphators painted their faces red, perhaps to imitate the red-painted flesh of statues of the Gods. The Romans used yellow ochre in their paintings to represent gold and skin tones, and as a background colour. It is found frequently in the murals of Pompeii . Ochre pigments are plentiful across Australia, especially

4998-616: The Mine Law Court became bogged down with disputes. Deep coal and iron reserves could not be mined without substantial investment and the Crown became determined to introduce the free market into the Forest. In 1777 Mine Law Court documents mysteriously disappeared from the Speech House where they were stored and the court fell into disarray. Most of the Court documents were later found to have been in

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5096-553: The Phoenicians as for other populations.” Greater-quality pigments and more intricate applications would typically indicate people of greater rank or particular significance within the community. Moreover, the presence and quality of pigments in a burial site may indicate the identity or social standing of the deceased. In addition to acting as offerings to the gods and protective symbols, pigments were employed to adorn grave goods including pottery, amulets, and other objects, so elevating

5194-404: The afterlife, and social hierarchy, thus providing a richer understanding of Phoenician customs and values. Ochre was the most commonly used pigment for painting walls in the ancient Mediterranean world . In Ancient Greece , red ochre was called μίλτος, míltos (hence Miltiades : "red-haired" or "ruddy"). In ancient Athens when Assembly was called, a contingent of public slaves would sweep

5292-637: The climax of the practice coinciding broadly with the emergence of Homo sapiens. Evidence of ochre's use in Australia is more recent, dated to 50,000 years ago, while new research has uncovered evidence in Asia that is dated to 40,000 years ago. A re-examination of artifacts uncovered in 1908 at Le Moustier rock shelters in France has identified Mousterian stone tools that were attached to grips made of ochre and bitumen . The grips were formulated with 55% ground goethite ochre and 45% cooked liquid bitumen to create

5390-652: The closure of maternity hospital facilities at the Dilke Hospital - so that it has become unusual to be born within the "Hundred of St Briavels" - and attempts by the UK government to exact commercial coal mining licence charges under the 1994 Coal Act adds further difficulties. Despite the modest level of activity, some Freemines do operate successfully, especially through diversification into non-traditional areas such as tourism and ochre mining. Freemining continues to be an important aspect of Forest of Dean culture and an important part of local identity. Coal Coal

5488-492: The decision to enter females onto the register for the first time in 2010. It is now understood that the qualification of "male", also incorporates "or female." The ancient administrative district, known as the " Hundred of St Briavels", is generally considered to be the whole of the statutory Forest of Dean and each parish adjoining it. And, as of 2010, the gender requirement has been recognised as archaic and women are now allowed to become freeminers. The Dean Forest Mines Act

5586-559: The digestive system while others, which are rich in iron, can assist with lethargy and fatigue. Ochre is also often mixed with plant oils and animal fats to create other medicines. This ochre was mined by Aboriginal people in pits and quarries across Australia; there are over 400 recorded sites, and many of these (including the Ochre Pits in the Tjoritja / West MacDonnell National Park ) are still in use. The National Museum of Australia has

5684-503: The drying out of the wood in canoes and the carvings of meeting houses; later missionaries estimated that it would last for 30 years. It was also roughly smeared over the face, especially by women, to keep off insects. Solid chunks of ochre were ground on a flat but rough surfaced rock to produce the powder. In Newfoundland its use is most often associated with the Beothuk , whose use of red ochre led them to be referred to as "Red Indians" by

5782-415: The earth of mountains, where particular seams like sulphur are found. And there, where these seams are, sinopia, green earth and other types of pigment are found...And the abovementioned pigments running through this landscape looked as a scar on the face of a man or of a woman looks...I went in behind with my little knife, prospecting at the scar of this pigment; and in this way, I promise you, I never sampled

5880-430: 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

5978-512: 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

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6076-620: The first Europeans to Newfoundland. The Beothuk may have also used yellow ochre to colour their hair. It was also used by the Maritime Archaic as evidenced by its discovery in the graves of over 100 individuals during an archaeological excavation at Port au Choix . Its use was widespread at times in the Eastern Woodlands cultural area of Canada and the US; the Red Ocher people complex refers to

6174-498: 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

6272-425: The grains of sand from the particles of ochre. The remaining mixture was then decanted in large basins, to further separate the ochre from the sand. The water was then drained, and the ochre was dried, cut into bricks, crushed, sifted, and then classified by colour and quality. The best quality was reserved for artists' pigments. In Britain , ochre was mined at Brixham , England . It became an important product for

6370-441: The ground of their dwellings, and that a paste of ochre was used for decorative purposes in every phase of their domestic life. We must assume no less, if we are to account for the veritable mines of ochre on which some of them lived... The Ancient Picts were said to paint themselves "Iron Red" according to the Gothic historian Jordanes . Frequent references in Irish myth to "red men" ( Gaelic : Fer Dearg) make it likely that such

6468-475: 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

6566-431: 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

6664-408: The local clay was richer in yellowish limonite or reddish hematite. The red earth from Pozzuoli near Naples was a salmon pink, while the pigment from Tuscany contained manganese, making it a darker reddish brown called terra di siena, or sienna earth. The 15th-century painter Cennino Cennini described the uses of ochre pigments in his famous treatise on painting. This pigment is found in

6762-450: The minerals of the Forest of Dean, but also allowed Freeminers to sell their gales to a non-Freeminers, weakening the Freeminer's control and opening up the forest to outside industrialists. The Coal Industry Nationalisation Act 1946 specifically exempted the Forest of Dean, due to its unique form of ownership and history, allowing Freemining privileges to continue intact. Some large colliery gales were subsequently compulsorily purchased by

6860-453: 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

6958-405: 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

7056-543: The name PY-43 (Pigment yellow 43) on the label, following the Colour Index International system. Over recent decades, red ochre has played a pivotal role in discussions about the cognitive and cultural evolution of early modern humans during the African Middle Stone Age. In Africa, evidence for the processing and use of red ochre pigments has been dated by archaeologists to around 300,000 years ago,

7154-407: 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

7252-455: 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

7350-581: The open space of the Agora with ropes dipped in miltos : those citizens that loitered there instead of moving to the Assembly area would risk having their clothes stained with the paint. This prevented them from wearing these clothes in public again, as failure to attend the Assembly incurred a fine. In England, red ochre was also known as "raddle", "reddle", or "ruddle" and was used to mark sheep and can also be used as

7448-489: The possession of local Crown officials (Deputy Gavellers), and they were produced as evidence at an inquiry some 50 years later. A royal commission was appointed in 1831 to inquire into the nature of the mineral interests and freemining customs in the Forest of Dean, leading to the passing of the Dean Forest Mines Act 1838 , which now forms the basis of Freemining law. It confirmed the Freeminers' exclusive right to

7546-456: 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

7644-518: The preservation of animal skins, among other uses. At Lake Mungo , in Western New South Wales , burial sites have been excavated and burial materials, including ochre-painted bones, have been dated to the arrival of people in Australia; " Mungo Man " (LM3) was buried sprinkled with red ochre at least 30,000 BP, and possibly as early as 60,000 BP. Ochre was also widely used as medicine and, when ingested, some ochres have an antacid effect on

7742-427: 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

7840-642: The site of the Blombos Cave in South Africa, dated to around 75,000 years ago. " Mungo Man " (LM3) in Australia was buried sprinkled with red ochre around 40,000 years ago. In Wales, the paleolithic burial called the Red Lady of Paviland from its coating of red ochre has been dated to around 33,000 years before present. Paintings of animals made with red and yellow ochre pigments have been found in paleolithic sites at Pech Merle in France (ca. 25,000 years old), and

7938-565: The spiritual purity of the interment. The visual impact of red ochre could also have been intended to preserve the appearance of the body or make it presentable for mourning ceremonies, ensuring that the deceased was honored appropriately. This vivid color would enhance the overall visual and emotional impact of funerary displays. In essence, the use of red ochre and other pigments in Phoenician funerary contexts highlights their cultural and symbolic importance, reflecting deep-seated beliefs about death,

8036-399: 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

8134-545: The use of the pigment as a food adulterant in sausage roll production whereby the accused apprentice was taught to soak brown bread in red ochre, salt , and pepper to give the appearance of beef sausage for the filling. As noted above, the industrial process for making ochre pigment was developed by the French scientist Jean-Étienne Astier in the 1780s, using the ochre mines and quarries in Roussillon , Rustrel, or Gargas in

8232-415: 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

8330-574: 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

8428-574: 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

8526-504: 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

8624-488: Was considered to be eternal and indestructible. The skin and bones of the gods were believed to be made of gold. The Egyptians used yellow ochre extensively in tomb painting, though occasionally they used orpiment , which made a brilliant colour, but was highly toxic, since it was made with arsenic . In tomb paintings, men were always shown with brown faces, women with yellow ochre or gold faces. Red ochre in Ancient Egypt

8722-417: Was developed by the French scientist Jean-Étienne Astier in the 1780s. He was from Roussillon in the Vaucluse department of Provence , and he was fascinated by the cliffs of red and yellow clay in the region. He invented a process to make the pigment on a large scale. First the clay was extracted from open pits or mines. The raw clay contained about 10 to 20 percent ochre. Then he washed the clay to separate

8820-602: 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

8918-408: 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

9016-490: 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

9114-403: Was evocative of blood and energy, red ochre represented life, death, and rebirth. It also represented the desire for resurrection and the belief in an afterlife. In order to honor the deceased and get them ready for their passage to the afterlife, these pigments, particularly red ochre, were most likely applied to their body or other grave goods as part of the burial rites. “Phoenicians' love of red

9212-563: Was mixed with some type of liquid raw material to create a rough paint. The liquid material was usually seal oil or cod liver oil in Newfoundland and Labrador, while Scandinavian recipes sometimes called for linseed oil . Red ochre paint was sometimes prepared months in advance and allowed to sit, and the smell of ochre paint being prepared is still remembered today. Variations in local recipes, shades of ore, and type of oil used resulted in regional variations in colour. Because of this, it

9310-606: 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 ,

9408-423: Was the pigment of choice for use in vernacular outbuildings and work buildings associated with the cod fishery. Deposits of ochre are found throughout Newfoundland, notably near Fortune Harbour and at Ochre Pit Cove. While earliest settlers may have used locally collected ochre, people were later able to purchase pre-ground ochre through local merchants, largely imported from England . The dry ingredient, ochre,

9506-777: Was used as a rouge, or lip gloss for women. Ochre-coloured lines were also discovered on the Unfinished obelisk at the northern region of the Aswan Stone Quarry , marking work sites. Ochre clays were also used medicinally in Ancient Egypt: such use is described in the Ebers Papyrus from Egypt, dating to about 1550 BC. Pigments, particularly red ochre, were essential to grave rituals in ancient Phoenician society. They were more than just cosmetics; they also had important symbolic and ritualistic connotations. With its vivid color that

9604-430: 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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