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The Story of Coal ~ 1920 Bray Studios; How Coal is Created and Mined
🕑 Added 2020-03-07 21:49:21 +0000 UTCmore at http://quickfound.net/
Silent.
Originally a public domain film from the National Archives or Library of Congress Prelinger Archives, slightly cropped to remove uneven edges, with the aspect ratio corrected, and one-pass brightness-contrast-color correction & mild video noise reduction applied.
https://en.wikipedia.org/wiki/Coal
Wikipedia license: http://creativecommons.org/licenses/by-sa/3.0/
Coal 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 formed when dead plant matter decays into peat and 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 the late Carboniferous (Pennsylvanian) and Permian times.
As a fossil fuel burned for heat, coal supplies about a quarter of the world's primary energy and two-fifths of its electricity. Some iron and steel making and other industrial processes burn coal.
The extraction and use of coal causes many premature deaths and much illness. The coal industry damages the environment, including by climate change as it is the largest anthropogenic source of carbon dioxide, 14 gigatonne (Gt) in 2016, which is 40% of the total fossil fuel emissions and almost 25% of total global greenhouse gas emissions. As part of the worldwide energy transition many countries have stopped using or use less coal, and the UN Secretary General has asked governments to stop building new coal plants by 2020. To meet the Paris Agreement target of keeping global warming to well below 2 °C (3.6 °F) coal use needs to halve from 2020 to 2030.
The largest consumer and importer of coal is China. China mines almost half the world's coal, followed by India with about a tenth. Australia accounts for about a third of world coal exports followed by Indonesia and Russia...
Emission intensity
Emission intensity is the greenhouse gas emitted over the life of a generator per unit of electricity generated. Of the currently widely used methods of generating electricity the emission intensity of coal and oil is high, as they emit around 1000g of CO2eq for each kWh generated; natural gas is medium emission intensity at around 500g CO2eq per kWh; and all other methods are typically low emission intensity of under 100g per kWh. The emission intensity of coal varies with type and generator technology and exceeds 1200g per kWh in some countries.
Energy density
The energy density of coal, that is its heating value, 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.
27.6% of world energy was supplied by coal in 2017 and Asia used almost three quarters of it.
Chemistry
Composition
The composition of coal is reported either as a proximate analysis (moisture, volatile matter, fixed carbon, and ash) or an ultimate analysis (ash, carbon, hydrogen, nitrogen, oxygen, and sulfur). The "volatile matter" does not exist by itself (except for some adsorbed methane) but designates the volatile compounds that are produced and driven off by heating the coal. A typical bituminous coal may have an ultimate analysis on a dry, ash-free basis of 84.4% carbon, 5.4% hydrogen, 6.7% oxygen, 1.7% nitrogen, and 1.8% sulfur, on a weight basis...
https://en.wikipedia.org/wiki/Coal_mining
Coal mining is the process of extracting coal from the ground. Coal is valued for its energy content and since the 1880s, has been widely used to generate electricity. Steel and cement industries use coal as a fuel for extraction of iron from iron ore and for cement production. In the United Kingdom and South Africa, a coal mine and its structures are a colliery, a coal mine – a pit, and the above-ground structures – a pit head. In Australia, "colliery" generally refers to an underground coal mine. In the United States, "colliery" has been used to describe a coal mine operation, but this usage is less common today.
Coal mining has had many developments over the recent years, from the early days of men tunneling, digging, and manually extracting the coal on carts to large open cut and long wall mines. Mining at this scale requires the use of draglines, trucks, conveyors, hydraulic jacks and shearers...
