Coal is found wedged between rock layers deep in the Earth’s crust. It can be found on all continents, and it can be divided into four grades based on the amount of carbon it holds. It is a fossil fuel because it is contains carbon from ancient plant life.
Is coal a rock, mineral or fossil?
Coal is an energy mineral (legally a mineral, scientifically a rock). Coal is fossil fuel (because it is derived from fossil plant remains). Coal is a solid hydrocarbon (because it consists mostly of carbon, hydrogen, and oxygen; in contrast, oil is a liquid hydrocarbon, and natural gas is a gaseous hydrocarbon).
Is coal a sedimentary rock?
Coal is considered a sedimentary rock. Some might classify it as a biologic sedimentary rock as it forms from the compaction and alteration of accumulated plant matter. Coal is classified into one of three types depending on its level of development. Lignite is a soft, brown coal and is the least developed form.
Where are coal mines located?
Poland relies on its own and imported coal for almost 70% of its energy, drawing criticism from the European Union and environmental organizations concerned about CO2 emissions and climate change. Most coal mines are located in the southern Silesia region. Many are at risk of explosions from the sudden release of methane.
What type of sedimentary rock is coal?
Coal is an organic sedimentary rock. Coal is formed by the biogenic and thermal decomposition of vegetal matter. When plants remains are buried underneath,the decompose and convert to peat through biogenic and thermogenic processes. With the increase in time, the volume decreases and the carbon content increases.
What is the geology of coal?
Coal is a combustible sedimentary rock formed from ancient vegetation which has been consolidated between other rock strata and transformed by the combined effects of microbial action, pressure and heat over a considerable time period. This process is commonly called 'coalification'.
Where is coal geologically found?
Some of the largest coal deposits are located in the Appalachian basin in the eastern U.S., the Illinois basin in the mid-continent region, and throughout numerous basins and coal fields in the western U.S. and Alaska. Learn more: Coal – A Complex Natural Resource.
What type of rock is coal found in?
sedimentary rockCoal is a sedimentary rock. Coal is altered through biological and burial-thermal processes into different ranks. Many sedimentary rocks are also altered through burial-thermal processes (increasing cementation, etc.).
What does coal look like on a rock?
Coal is a black or brownish-black sedimentary rock that can be burned for fuel and used to generate electricity.
Why is coal a sedimentary rock?
Being composed of carbon, coal forms a carbonaceous deposit. Having been transported and accumulated in a single deposit it is sedimentary. Having undergone metamorphosis and petrification it is a rock. Consequently it is reasonable to classify coal as a carbonaceous sedimentary rock.
Why is coal found where it is?
Lush vegetation grew in swamps around the seas. Over time the plant material was buried under layers of sand and mud. Over millions of years, pressure from the overlying rocks and heat from the Earth changed the plant matter into coal.
What does natural coal look like?
Coal is a combustible black or brownish-black sedimentary rock with a high amount of carbon and hydrocarbons.
Is coal found in igneous rocks?
Coal is an inflammable organic substance, composed mainly of hydrocarbons, found in the form of sedimentary rocks and capable of being used as fuel to supply heat or light or both.
Is coal a hard or soft rock?
It is a hard, brittle, and black lustrous coal, often referred to as hard coal, containing a high percentage of fixed carbon and a low percentage of volatile matter. Bituminous: Bituminous coal is a middle rank coal between subbituminous and anthracite.
Is coal a mineral or a rock?
Coal is not a mineral because it does not qualify to be one. A mineral is made of rocks. Coal is non-living and made up of atoms of elements. Minerals are not formed from living things such as plants or animals.
How many years of coal is left?
Based on U.S. coal production in 2020, of about 0.535 billion short tons, the recoverable coal reserves would last about 470 years, and recoverable reserves at producing mines would last about 25 years.
Why is coal found in mountains?
The sustained geologic pressure and heat involved in creating the mountains baked and compressed the peat from those old bogs into seams of coal from a few inches to several feet thick. First mined in the 19th century, Appalachian coal dominated the U.S. market for 100 years.
Where is coal found in the earth's layers?
Coal deposits are found in sedimentary rock basins, where they appear as successive layers, or seams, sandwiched between strata of sandstone and shale.
How does coal form in mountains?
The sustained geologic pressure and heat involved in creating the mountains baked and compressed the peat from those old bogs into seams of coal from a few inches to several feet thick.
Where is coal found?
Coal is found all over the world—including the United States—predominantly in places where prehistoric forests and marshes existed before being buried and compressed over millions of years. Some of the largest coal deposits are located in the Appalachian basin in the eastern U.S., the Illinois basin in the mid-continent region, and throughout numerous basins and coal fields in the western U.S. and Alaska.
What is the name of the coal that is formed by pressure and heat?
This sample is of bituminous coal, a middle rank coal (between subbituminous and anthracite) formed by additional pressure and heat on lignite. Usually has a high Btu value and may be referred to as "soft coal." Read more about USGS coal research here:
What is a canning coal?
Cannel coal is a type of bituminous coal that is also sometimes referred to as a type of oil shale. It's name likely came from the word " candle ." Cannel coal was once used as a source for kerosene. Read more about our coal research here:
What is coal used for?
Coal is primarily used as fuel to generate electric power in the United States. In coal-fired power plants, bituminous coal, subbituminous coal, or lignite is burned. The heat produced by the combustion of the coal is used to convert water into high-pressure steam, which drives a turbine, which produces electricity.
What is the USGS coal resource assessment?
The U.S. Coal Resources and Reserves Assessment Project, as part of the U.S. Geological Survey (USGS) Energy Resources Program, conducts systematic, geology-based, regional assessments of significant coal beds in major coal basins in the United States.
What is the lowest rank of coal?
A sample of lignite, the lowest rank of coal. It is primarily mined for burning in steam-generation power plants. Read more about our coal research here: https://www.usgs.gov/centers/cersc/science/us-coal-resources-and-reserves-assessment
What are the four types of coal?
The four ranks are: Anthracite : The highest rank of coal.
How Does Coal Form?
Coal forms from the accumulation of plant debris, usually in a swamp environment. When a plant dies and falls into the swamp, the standing water of the swamp protects it from decay. Swamp waters are usually deficient in oxygen, which would react with the plant debris and cause it to decay. This lack of oxygen allows the plant debris to persist. In addition, insects and other organisms that might consume the plant debris on land do not survive well under water in an oxygen-deficient environment.
How is coal used in manufacturing?
It is used as a source of heat for manufacturing processes. For example, bricks and cement are produced in kilns heated by the combustion of a jet of powdered coal. Coal is also used as a power source for factories. There it is used to heat steam, and the steam is used to drive mechanical devices.
What is Coal "Rank"?
The "rank" of a coal is a measure of how much change has occurred. Sometimes the term "organic metamorphism" is used for this change.
What is coal fired power plant?
Coal-Fired Power Plant: Photo of a power plant where coal is burned to produce electricity. The three large stacks are cooling towers where water used in the electricity generation process is cooled before reuse or release to the environment. The emission streaming from the right-most stack is water vapor.
What is the carbon content of bituminous coal?
It has a carbon content of between 77 and 87% on a dry ash-free basis and a heating value that is much higher than lignite or sub bituminous coal. On the basis of volatile content, bituminous coals are subdivided into low-volatile bituminous, medium-volatile bituminous, and high-volatile bituminous.
What is the most abundant rank of coal?
On the basis of heating value, it is subdivided into sub bituminous A, sub bituminous B, and sub bituminous C ranks. Bituminous. Bituminous is the most abundant rank of coal. It accounts for about 50% of the coal produced in the United States.
What is brown coal?
In Europe, Australia, and the UK, some low-level lignites are called "brown coal.". Sub Bituminous. Sub bituminous coal is a lignite that has been subjected to an increased level of organic metamorphism. This metamorphism has driven off some of the oxygen and hydrogen in the coal.
Where are coal seams found?
Coal seams exist on every continent. The largest coal reserves are in the United States, Russia, China, Australia, and India.
What is coal made of?
Coal is a black or brownish-black sedimentary rock that can be burned for fuel and used to generate electricity. It is composed mostly of carbon and hydrocarbon s , which contain energy that can be released through combust ion (burning).
What was coal used for in the 19th century?
Cannel coal was extensively used as a source of coal oil in the 19th century. Coal oil is made by heating cannel coal with a controlled amount of oxygen, a process called pyrolysis. Coal oil was used primarily as fuel for streetlights and other illumination. The widespread use of kerosene reduced the use of coal oil in the 20th century.
What is the lowest rank of coal?
Lignite coal is the lowest rank of coal. It has carbonized past the point of being peat, but contains low amounts of energy—its carbon content is about 25-35%. It comes from relatively young coal deposits, about 250 million years old.
Where is lignite used?
Most lignite coal is used in power stations very close to where it was mined. Lignite is mainly combusted and used to generate electricity. In Germany and Greece, lignite provides 25-50% of electricity generated by coal. In the U.S., lignite deposits generate electricity mostly in the states of North Dakota and Texas.
Which type of coal has the most carbon?
Anthracite is the highest rank of coal. It has the most amount of carbon, up to 97%, and therefore contains the most energy. It is harder, more dense, and more lustrous than other types of coal. Almost all the water and carbon dioxide have been expelled, and it does not contain the soft or fibrous sections found in bituminous coal or lignite.
How is coal ranked?
Coal is ranked according to how much it has changed over time. Hilt's Law states that the deeper the coal seam, the higher its rank. At deeper depths, the material encounters greater temperatures and pressure, and more plant debris is transformed into carbon.
What is coal geology?
Coal is an interdisciplinary science generally known as coal geology, which is an integration of stratigraphy, sedimentology, petrology, chemistry, and botany . The applications of stratigraphy and sedimentology in coal geology are basic for understanding the origin of peat in the depositional environments of coal at the local and basin-scale dimensions (see Chapters 2–3Chapter 2Chapter 3 ). Stratigraphy is important to correlations as sedimentology is to depositional systems with both significantly affecting the aerial distribution, thickness, and occurrence of coalbeds. The understanding of these principles is basic to coal resource–reserve assessments, where failure to recognize their role can mean an under- or overestimation of the total amount of coal in the ground (see Chapter 6 ). Oftentimes, the variability of coal resource estimates is caused by errors in correlations. This leads to miscalculations of coalbed gas resources and reserves as well as misunderstanding of the framework and characterization of coal reservoirs (see Chapter 6 ).
Why are coal beds bypassed?
In many developing coal basins in the United States and other countries, thin coal beds are bypassed because of insufficient gas content to be an operationally cost-effective and economical well . However, deployment of cased-hole completion of multiple coal beds technically makes production of coalbed gas from thin coal beds feasible. This concept makes more sense in coal basins where thick coal beds split into numerous thin coal beds and remerge ( Flores, 1986, 2004). Conceptually, where the coal bed is thick, the strategy should be single-bed completion and where the same beds split, the strategy should be multiple-bed completion. However, this concept must be tempered by sedimentology and stratigraphy of the intervening intervals between the coal beds. Channel deposits consisting of sandstones and floodplain deposits consisting of siltstones and mudstones can split thick coal beds. Using the principle of differential compaction of the various sediment types, relatively noncompatible sandstones produce thicker or vertically more widely spaced coal-to-sandstone-to-coal interval. In contrast, the compactible mudstones and siltstones produce thinner or vertically closely spaced zones of coal-to-mudstone/siltstone-to-coal interval. Thus, the finer grained lithofacies-to-coal association may be best developed technically and economically using multibed completion. Based on this scenario, the most promising procedure for improvement of coalbed gas development with analysis of alternative completion technology to adopt is the use of coal geology based on sedimentology, stratigraphy, and depositional environments of the coal-bearing rocks.
Is geology a science?
Geology as a science studies our whole planet, but it also treats in greater detail narrower territories of interest from the practical standpoint. The constant demands of practice have brought about a situation in which today we have a number of very well developed disciplines of applied geology.
What is coal classified as?
There are several international standards for coal. The classification of coal is generally based on the content of volatile substances. But the most important distinction is thermal coal (also known as steam coal), which is burned to generate electricity through steam; and metallurgical coal (also known as coking coal), which is burned at high temperature to make steel.
What is the composition of coal?
A typical bituminous coal may have a final analysis on a dry, ash-free basis of 84.4% carbon, 5.4% hydrogen, 6
What is the grade of coal?
The grade of coal produced depended on the maximum pressure and temperature reached; Lignite (also called “brown coal”) and sub-bituminous coal, bituminous coal or anthracite (also called “hard coal” or “hard coal”) produced under relatively mild conditions is produced with increasing temperature and pressure.
How is coal density controlled?
Coal density is controlled in part by the presence of pores that persist throughout charring. Pore sizes and pore distribution are difficult to measure; however, pores appear to have three size ranges:
What is bituminous coal?
Bituminous coal, a dense sedimentary rock, usually black, but sometimes dark brown, often with well-defined bands of shiny and dull material. It is primarily used as a fuel in the production of steam-electric power and in the production of coke. In the UK it is known as steam coal and has historically been used to raise steam in steam locomotives and ships.
Why is coal important to the Earth?
Coal is a common energy and chemical source. Terrestrial plants necessary for the development of coal were not abundant until the Carboniferous period (358.9 million to 298.9 million years ago), large sedimentary basins containing rocks of Carboniferous age and younger are known on almost every continent, including Antarctica. The presence of large coal deposits in regions with currently arctic or subarctic climates (such as Alaska and Siberia) is due to climate changes and tectonic movement of crustal plates that have moved older continental masses over the Earth’s surface, sometimes through the subtropical and even tropics. regions. Some areas (like Greenland and most of northern Canada) lack coal because the rocks found there predate the Carboniferous Period, and these regions, known as continental shields, lack the abundant terrestrial plant life needed for the formation of large coal deposits.
How dense is coal?
Knowing the physical properties of coal is important in the preparation and use of coal. For example, coal density ranges from about 1.1 to about 1.5 megagrams per cubic metre, or grams per cubic centimeter. Coal is slightly denser than water and significantly less dense than most rocks and mineral matter. Density differences make it possible to improve the quality of a coal by removing most of the rock matter and sulfide-rich particles through heavy liquid separation.
What is coal made of?
5. Description. Coal is a combustible, sedimentary rock with a brownish-black or even entirely black color. Coal is primarily composed of carbon, with smaller, varying quantities of hydrogen, nitrogen, sulfur and oxygen. It is classified into different types, based on its composition and time of formation. Namely, the most important varieties of ...
How is coal extracted from the earth?
Production. Coal can be extracted from the earth either by surface mining or underground mining, depending on its depth of location below the land surface. If deposits occur less than 200 feet below the surface of land, surface mining can be put to action to retrieve coal.
How did carbonization occur?
As this vegetation moved into greater depths below the surface of land, the natural biodegradation processes were halted. Instead, the conditions of concurrent high temperatures and high pressures found underneath the surface led to the gradual conversion of plant matter into coal. This process is referred to as "carbonization". The quality of the coal formed is determined by a number of factors, such as the nature of the vegetation from which it originated, the depth at which the carbonization process started, the temperature and pressure conditions through the process, as well as the time taken for the carbonization process to form the resultant coal.
What is the carbon content of bituminous coal?
The properties of sub-bituminous and bituminous coal lie in between those of anthracite and lignite. Bituminous coal has a fixed carbon content of 77-87%, and is the most abundant classification among all other varieties of coal. Bituminous coal accounts for nearly 50% of the coal produced in United States. 4. Location.
What are the major coal regions in the United States?
Within the United States, there are three major regions with large-scale coal mining operations, namely being the Western Coal Region, the Appalachian Coal Region, and the Interior Coal Region . Each of these regions somewhat specializes in producing different grades and varieites of this important energy source. 3.
What are the products of coal combustion?
Several important industrial chemicals are manufactured from the by-products of coal combustion. Benzene, naphthalene, and phenol, for instance, are each manufactured using coal tar. Ammonia-based fertilizers and salts are produced using the ammonia generated from coal combustion as well.
Where is bituminous coal found?
Bituminous coal accounts for nearly 50% of the coal produced in United States. 4. Location. Coal reserves are found within a large number of countries, spanning all continents other than Antarctica. The largest proven, and recoverable, reserves of coal are to be found within the US, the Russian Federation, and China.
Where did coal come from?
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. However, many significant coal deposits are younger than this and originate from the Mesozoic and Cenozoic eras.
Why is coal important?
As of 2016, coal remains an important fuel as it supplied about a quarter of the world's primary energy and two-fifths of 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.
What is the process of coalification?
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 wetland areas. In these wetlands, the process of coalification began when dead plant matter was protected from biodegradation and oxidation, usually by mud or acidic water, and was converted into peat. This trapped the carbon in immense peat bogs that were eventually deeply buried by sediments. Then, over millions of years, the heat and pressure of deep burial caused the loss of water, methane and carbon dioxide and increased in 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 (also called "hard coal" or "black coal") produced in turn with increasing temperature and pressure.
What temperature is required for coalification?
Of 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).
Why is metallurgical coal more volatile than thermal coal?
The price of metallurgical coal is volatile and much higher than the price of thermal coal because metallurgical coal must be lower in sulfur and requires more cleaning. Coal futures contracts provide coal producers and the electric power industry an important tool for hedging and risk management .
How does carbonization occur?
Carbonization proceeds primarily by dehydration, decarboxylation, and demethanation. Dehydration removes water molecules from the maturing coal via reactions such as
Why is coal called pitcoal?
The alternative name was "pitcoal", because it came from mines. The development of the Industrial Revolution led to the large-scale use of coal, as the steam engine took over from the water wheel. In 1700, five-sixths of the world's coal was mined in Britain.
What is Jet?
Jet is a black organic rock that forms when pieces of woody material are buried in sediment and are coalified. Though very similar to coal, it is less friable. Jet can be cut, carved, and polished to a bright luster. People have used jet for thousands of years to produce gemstones, beads, and many other objects.
How Does Jet Form?
The material known as "jet" is very similar to coal, but the way that it forms is different. Most coal seams form when a swamp containing abundant woody material is buried; that woody material is then compacted, undergoes organic degradation, and is heated. The result is a coal seam.
Physical Properties of Jet
Jet has a few properties that make it useful and desirable. These have dictated its use across the centuries. The first of these properties is its ability to be easily carved or cut into shapes. Jet is soft and has a uniform texture, which allows it to be carved with precision.
History of Human Use
The most important source of jet has always been the eastern coast of England and Scotland, centered near what is now the community of Whitby. In this area people found small, black, rounded, light-weight stones along the shoreline.
Use of Jet and Jet Substitutes Today
As a fashionable item, jet declined quickly during the Great Depression when the demand for manufactured goods of all kinds collapsed. It never regained its Victorian popularity and is used infrequently today.
Introduction
- “Coal miner” redirects here. For the John J. Szaton statue, see Coal Miner (statue). Shortwall mining, a technique presently comprising under 1 % of deep coal production, involves using a continuous mining machine with movable roof supports, much like longwall. The continual miner shears coal panels 150 to 200 ft (45 to 60 metres) wide and most one...
Causes
Formation
Classification
Uses
- Coal is an organic sedimentary rock that forms from the accumulation and preservation of plant materials, usually in a swamp environment. Coal is a combustible rock and, along with oil and natural gas, it is one of the three most important fossil fuels. Coal has a wide range of uses; the most important use is for the generation of electricity.
Other uses
- Coal forms from the accumulation of plant debris, usually in a swamp environment. When a plant dies and falls into the swamp, the standing water of the swamp protects it from decay. Swamp waters are usually deficient in oxygen, which would react with the plant debris and cause it to decay. This lack of oxygen allows the plant debris to persist. In addition, insects and other organ…