What do coal beds originate in

Blaine Cecil Sandra G. How to cite. Introduction Coal is defined in the Glossary of Geology , p. This is a preview of subscription content, log in to check access. Cecil, C. The concept of autocyclic and allocyclic controls on sedimentation and stratigraphy, emphasizing the climatic variable. In Cecil, C. Special Publication, 77 , pp. Google Scholar. Precipitation models for sediment supply in warm climates. Coal Geol. Jackson, J.

Glossary of Geology, 4th edn. American Geol. Institute, Virginia, p. Wood, G. 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. Coking coal is used in large-scale industrial processes.

The coal is coke d, a process of heating the rock in the absense of oxygen. This reduces the moisture content and makes it a more stable product. The steel industry relies on coking coal. Bituminous coal accounts for almost half of all the coal that is used for energy in the United States.

It is mainly mined in Kentucky, Pennsylvania, and West Virginia. Anthracite Anthracite is the highest rank of coal. 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. Because anthracite is a high-quality coal, it burns cleanly, with very little soot.

It is more expensive than other coals, and is rarely used in power plants. Instead, anthracite is mainly used in stoves and furnaces. Anthracite is also used in water- filtration systems. It has tinier pores than sand, so more harmful particles are trapped.

This makes water safer for drinking, sanitation , and industry. Anthracite can typically be found in geographical areas that have undergone particularly stressful geologic activity. For example, the coal reserves on the Allegheny Plateau in Kentucky and West Virginia stretch to the base of the Appalachian Mountains.

Here, the process of orogeny , or mountain formation, contributed to temperatures and pressures high enough to create anthracite. China dominates the mining of anthracite, accounting for almost three-quarters of anthracite coal production. Graphite Graphite is an allotrope of carbon, meaning it is a substance made up only of carbon atoms.

Diamond is another allotrope of carbon. Graphite is the final stage of the carbonization process. Graphite conducts electricity well, and is commonly used in lithium ion batteries. It can be used in products such as fire-resistant doors, and missile parts such as nose cones. Coal Mining Coal can be extracted from the earth either by surface mining or underground mining. Once coal has been extracted, it can be used directly for heating and industrial processes or to fuel power plants for electricity.

Surface Mining If coal is less than 61 meters feet underground, it can be extracted through surface mining. In surface mining, workers simply remove any overlying sediment, vegetation, and rock, called overburden. Economically, surface mining is a cheaper option for extracting coal than underground mining. About two and a half times as much coal can be extracted per worker, per hour, than is possible with underground mining.

The environmental impacts of surface mining are dramatic. The landscape is literally torn apart, destroying habitats and entire ecosystem s. Surface mining can also cause landslide s and subsidence when the ground begins to sink or cave in. Toxic substances leach ing into the air, aquifer s, and water table s may endanger the health of local residents.

In the United States, the Surface Mining Control and Reclamation Act of regulates the process of coal mining, and is an effort to limit the harmful effects on the environment. The act provides funds to help fix these problems and clean up abandoned mining sites. The three main types of surface coal mining are strip mining, open-pit mining, and mountaintop removal MTR mining.

Surface Mining: Strip Mining Strip mining is used where coal seams are located very near the surface and can be removed in massive layers, or strips. Overburden is usually removed with explosives and towed away with some of the largest vehicles ever made. Dump trucks used at strip mines often weigh more than tons and have more than 3, horsepower.

Strip mining can be used in both flat and hilly landscapes. Strip mining in a mountainous area is called contour mining. Contour mining follows the ridges, or contours, around a hill. A pit, sometimes called a borrow, is dug in an area. This pit becomes the open-pit mine , sometimes called a quarry. Open-pit mines can expand to huge dimensions, until the coal deposit has been mined or the cost of transporting the overburden is greater than the investment in the mine.

Open-pit mining is usually restricted to flat landscapes. After the mine has been exhausted, the pit is sometimes converted into a landfill. After the summit is cleared of vegetation, explosives are used to expose the coal seam. After the coal is extracted, the summit is sculpted with overburden from the next mountaintop to be mined. By law, valuable topsoil is supposed to be saved and replaced after mining is done. Barren land can be replanted with trees and other vegetation.

Mountaintop removal began in the s as a cheap alternative to underground mining. It is now used for extracting coal mainly in the Appalachian Mountains of the U.

MTR is probaby the most controversial coal mining technique. The environmental consequences are radical and severe. Waterways are cut off or contaminated by valley fill. Habitats are destroyed. Toxic byproduct s of the mining and explosive processes can drain into local waterways and pollute the air.

Miners travel by elevator down a mine shaft to reach the depths of the mine, and operate heavy machinery that extracts the coal and moves it above ground. The immediate environmental impact of underground mining appears less dramatic than surface mining.

There is little overburden, but underground mining operations leave significant tailings. Tailings are the often-toxic residue left over from the process of separating coal from gangue , or economically unimportant minerals.

Toxic coal tailings can pollute local water supplies. To miners, the dangers of underground mining are serious. Underground explosions, suffocation from lack of oxygen, or exposure to toxic gases are very real threats. To prevent the buildup of gases, methane must be constantly ventilated out of underground mines to keep miners safe. There are three major types of underground coal mining: longwall mining, room-and-pillar mining, and retreat mining. Underground Mining: Longwall Mining During longwall mining , miners slice off enormous panels of coal that are about 1 meter 3 feet thick, kilometers The panels are moved by conveyor belt back to the surface.

The roof of the mine is maintained by hydraulic supports known as chock s. As the mine advances, the chocks also advance. The area behind the chocks collapses. Longwall mining is one of the oldest methods of mining coal.

Before the widespread use of conveyor belts, ponies would descend to the deep, narrow channels and haul the coal back to the surface. Today, almost a third of American coal mines use longwall mining.

Columns pillars of coal support the ceiling and overburden. The rooms are about 9 meters 30 feet wide, and the support pillars can be 30 meters feet wide. There are two types of room-and-pillar mining: conventional and continuous. In conventional mining, explosives and cutting tools are used. In continuous mining, a sophisticated machine called a continuous miner extracts the coal. In developing countries, room-and-pillar coal mines use the conventional method. Underground Mining: Retreat Mining Retreat mining is a variation of room-and-pillar.

When all available coal has been extracted from a room, miners abandon the room, carefully destroy the pillars, and let the ceiling cave in. Remains of the giant pillars supply even more coal. Retreat mining may be the most dangerous method of mining. A great amount of stress is put on the remaining pillars, and if they are not pulled out in a precise order, they can collapse and trap miners underground. How We Use Coal People all over the world have been using coal to heat their homes and cook their food for thousands of years.

Coal was used in the Roman Empire to heat public baths. In the Aztec Empire, the lustrous rock was used for ornaments as well as fuel. The Industrial Revolution was powered by coal. It was a cheaper alternative than wood fuel, and produced more energy when burned. Coal provided the steam and power needed to mass-produce items, generate electricity, and fuel steamships and trains that were necessary to transport items for trade.

Today, coal continues to be used directly heating and indirectly producing electricity. Coal is also essential to the steel industry. Fuel Around the world, coal is primarily used to produce heat. Coal can be burned by individual households or in enormous industrial furnace s. It produces heat for comfort and stability, as well as heating water for sanitation and health. Electricity Coal-fired power plants are one of the most popular ways to produce and distribute electricity.

In coal-fired power plant s, coal is combusted and heats water in enormous boilers. The boiling water creates steam, which turns a turbine and activates a generator to produce electricity. Poland, China, Australia, and Kazakhstan are other nations that rely on coal for electricity. Coke Coal plays a vital role in the steel industry. In order to produce steel, iron ore must be heated to separate the iron from other minerals in the rock.

In the past, coal itself was used to heat and separate the ore. However, coal releases impurities such as sulfur when it is heated, which can make the resulting metal weak. As early as the 9th century, chemists and engineer s discovered a way to remove these impurities from coal before it was burned. This drives off impurities such as coal gas, carbon monoxide, methane, tars, and oil.

The resulting material—coal with few impurities and high carbon content—is coke. The method is called coking. The hot air ignites the coke, and the coke melts the iron and separates out the impurities. The resulting material is steel. Coke provides heat and chemical properties that gives steel the strength and flexibility needed to build bridges, skyscrapers, airports, and cars.

Many of the biggest coal producers in the world the United States, China, Russia, India are also among the biggest steel producers. Japan, another leader in the steel industry, does not have significant coal reserves.

Synthetic Products The gases that are released during the coking process can be used as a source of power. Coal gas can be used for heat and light. Coal can also be used to produce syngas , a combination of hydrogen and carbon monoxide.

Syngas can be used as a transportation fuel similar to petroleum or diesel. In addition, coal and coke byproducts can be used to make synthetic materials such as tar, fertilizers, and plastics. Coal and Carbon Emissions Burning coal releases gases and particulate s that are harmful to the environment. Carbon dioxide is the primary emission. It is called a greenhouse gas because it absorbs and retains heat in the atmosphere, and keeps our planet at a livable temperature.

In the natural carbon cycle , carbon and carbon dioxide are constantly cycled between the land, ocean, atmosphere, and all living and decomposing organisms. Carbon is also sequester ed, or stored underground. This keeps the carbon cycle in balance. However, when coal and other fossil fuels are extracted and burned, they release sequestered carbon into the atmosphere, which leads to a build-up of greenhouse gases and adversely affects climate s and ecosystems.

Other Toxic Emissions Sulfur dioxide and nitrogen oxides are also released when coal is burned. These contribute to acid rain , smog , and respiratory illness es. Mercury is emitted when coal is burned. In the atmosphere, mercury is usually not a hazard. In water, however, mercury transforms into methylmercury, which is toxic and can accumulate in fish and organisms that consume fish, including people.

Fly ash which floats away with other gases during coal combustion and bottom ash which does not float away are also released when coal is combusted. Depending on the composition of the coal, these particulates can contain toxic elements and irritants such as cadmium, silicon dioxide, arsenic, and calcium oxide. Unfortunately, fly ash is often stored in landfills or power plants, and can drain into groundwater.

As a response to this environmental hazard, fly ash is being used as a component of concrete , thereby isolating it from the natural environment. Many countries do not regulate their coal industries as strictly as the U. Coal Fires Under the right conditions of heat, pressure, and ventilation, coal seams can self-ignite and burn underground.

Lightning and wildfires can also ignite an exposed section of the coal seam, and smoldering fire can spread along the seam. Coal fires emit tons of greenhouse gases into the atmosphere. Even if the surface fire is extinguished, the coal can smolder for years before flaring up and potentially starting a wildfire again. Coal fires can also begin in mines as a result of an explosion. Once coal catches fire and begins smoldering, it is extremely difficult to extinguish.

Advantages and Disadvantages Advantages Coal is an important part of the world energy budget. It is relatively inexpensive to locate and extract, and can be found all over the world. Unlike many renewable resources such as solar or wind , coal production is not dependent on the weather. It is a baseload fuel, meaning it can be produced 24 hours a day, 7 days a week, days a year.

We use and depend on many things that coal provides, such as heat and electricity to power our homes, schools, hospitals, and industries. Steel, vital for constructing bridges and other buildings, relies on coke for almost all production.

Coal byproducts, such as syngas, can be used to make transportation fuels. Coal mining also provides economic stability for millions of people worldwide.