Technical Announcements. Employees in the News. Emergency Management. Survey Manual. 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. In , about 23 percent of all electricity in the United States was generated by coal-fired power plants, according to the U.
Energy Information Administration. Certain types of bituminous coal can also be used in making steel. Coal used for steel making needs to be high in carbon content and low in moisture, ash, sulfur, and phosphorous content.
Coal that meets these specifications is known as metallurgical coal. Coal also has a myriad of other uses, including in cement production, carbon fibers and foams, medicines, tars, synthetic petroleum-based fuels, and home and commercial heating. The U. In , coal-fired power plants provided Federal, state and local policy makers will gather in Casper, Wyoming, on May to examine science issues associated with the development of coalbed methane.
The two-day conference and field trip, sponsored by the U. Geological Survey USGS , will examine a number of topics including: what is coalbed methane, how it forms, where it occurs, how it is developed, and consequences of development. Cannel coal used to be popular as a fireplace coal because it had little smoke and thus had less Koffing and Weezing present This sample is of peacock coal.
Peacock coal is not a specific class of coal, but rather the name for an effect in which oxidizing materials in the coal create a dazzling array of colors on the surface of the coal.
Usually it is short-lived, as the material fully oxidizes away shortly after exposed to air. Read more about our coal research here:. Energy Information Administration. Learn more: U. What are the types of coal? The four ranks are: Anthracite : The highest rank of coal. It is a hard, brittle, and black lustrous coal, often 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. In , about 23 percent of Filter Total Items: 3. Year Published: Assessing U. Shaffer, Brian N. View Citation. Shaffer, B. Geological Survey Fact Sheet —, 6 p. Year Published: Coal--a complex natural resource : an overview of factors affecting coal quality and use in the United States Schweinfurth, Stanley P.
Coal--a complex natural resource : an overview of factors affecting coal quality and use in the United States; ; CIR; ; Schweinfurth, Stanley P. Filter Total Items: 1. Date published: October 23, Filter Total Items: 6.
List Grid. Coal is formed in sedimentary basins. Sedimentary basins are regions where the Earth has subsided or sunk down. Water and sediments then flow into the basin and they fill with layers of sediments. Australia's black coal resources range from Permian to Jurassic in age to million years old , although most are Permian in age.
During this time, the climate was warm in Australia, and Eastern Australia, including the Sydney Basin was covered by large, meandering rivers, marshes, bogs and swamps. The sediments deposited in these environments eventually formed rocks such as shale, sandstone and coal. Brown coal in Australia formed more recently than the black coals.
These are mostly of Paleogene age 66 to 23 million years old. Coal is a sedimentary rock formed when abundant plant material is covered by sediments and the material accumulates faster than it can decay. The weight of the overlying sediments compacts the organic layers, increasing the temperature and pressure, which leads to physical and chemical changes to the plant material.
Water, carbon dioxide and methane are produced and escape, so the material becomes progressively enriched in carbon. With increasing time, and higher heat and pressure, the plant material first forms into peat, then is converted into brown coal, then sub-bituminous coal, bituminous coal, and lastly anthracite. Australia has the fourth-largest share of coal reserves in the world. Since the late s about million tonnes of black coal and about million tonnes of brown coal have been mined in Australia and the industry still provides significant employment, capital investment and domestic and export income to the national economy.
These two states are also the largest coal producers. Locally important black coal mining operations also include Collie in Western Australia, and Fingal and Kimbolton in Tasmania. The Gippsland Basin in Victoria contains a substantial world-class deposit where seams can be up to m thick. Minor resources occur in Tasmania's Longford Basin. Currently, brown coal is only mined in Victoria where the open-cut mines at Loy Yang and Yallourn supply coal to nearby power stations.
Brown coal is also mined at Maddingley to produce soil conditioners and fertilisers. Other products from Victorian brown coal are briquettes for industrial and domestic use and low-ash and low-sulphide char products.
Open-cut mining is possible because coal seams are close to the surface. Many brown coal beds lie close to the surface and can be hundreds of metres thick, so can be extracted easily and cheaply. Firstly the topsoil is removed and stored for use later in restoring the disturbed land. The surface rock called overburden covering the coal is then blasted with explosives and removed by excavators.
The uncovered coal is in turn then blasted to break up the layers and loaded into large trucks which can hold up to tonnes of material. The coal is transported to the processing plant where impurities are removed. Coal that is deeper than a few hundred metres under the surface must be extracted using two underground mining methods.
Some coal is mined by the Bord and Pillar method. This is where a machine continually cuts into the coal. It tunnels through the coal seams leaving pillars supported by roof bolts to hold up the roof.
An alternative is longwall mining, which uses a large cutting blade to slice across the coal layer to remove the coal seam. The coal is then transported to the surface on a conveyor belt. After the coal is mined the machine is dismantled and relocated to another section of the mine allowing the roof to collapse behind.
Advances in technology have led to the introduction of automated longwall mining systems. In addition, some mining companies are using driverless trucks, trains and drones to improve safety and gather information. Black coal can be used without any processing, but is usually crushed, screened and sorted according to customer requirements.
Sometimes it is also washed to remove any pieces of waste minerals that do not burn. This improves the quality and reduces the production of ash when the coal is burned. To wash the coal it is placed into tanks with liquids and chemicals which assist in recovering more of the coal as it floats to the surface.
0コメント