Coal mining industry

Industry Snapshot

GENERAL INDUSTRY: Energy

CAREER CLUSTER: Agriculture, Food, and Natural Resources

SUBCATEGORY INDUSTRIES:Anthracite Mining; Bituminous Coal and Lignite Surface Mining; Bituminous Coal Underground Mining; Coal Mining Blasting Services on a Contract Basis; Exploration Services for Coal on a Contract Basis; Mine Shaft Sinking Services on a Contract Basis; Mine Tunneling on a Contract Basis; Stripping and Overburden Removal on a Contract Basis; Support Activities for Coal Mining

RELATED INDUSTRIES:Electrical Power Industry; Mining Industry; Petroleum and Natural Gas Industry

ANNUAL DOMESTIC REVENUES: US$27.6 billion (IBISWorld, 2024)

ANNUAL GLOBAL REVENUES: US$2.5 trillion (IBISWorld, 2024)

NAICS NUMBERS: 2121, 213113

Summary

The coal mining industry locates coal, extracts it from the earth, processes it, and sells it for use in generating energy and for other industrial purposes. Miners often extract coal from horizontal sedimentary layers in the ground, though the processes used for coal extraction depend on the location of the coal, the type of coal being extracted, and the thickness and lateral extent of the coal bed. Coal close to the surface can sometimes be surface mined by removing overlying sediment to expose it. Coal located deeper underground may require mines to be constructed. Coal is widespread throughout much of the world, so mining is a worldwide industry. However, the industry in the United States and many other countries generally declined over the course of the twentieth and twenty-first centuries as other energy resources increased in popularity, in part due to environmental concerns over coal. Many smaller coal companies have shut down or been incorporated into larger companies.

History of the Industry

Coal has been used for heating for thousands of years. For example, the Welsh used it for this purpose three to four thousand years ago, while the Romans heated public baths by burning coal in the second century CE. By the twelfth century, people in England were using coal for heating since some coal was easily obtained at the surface and burning it produced more heat than did burning wood. By the early eighteenth century, industries were heating coal in air-free chambers to produce coke. Coke burns with a much hotter flame than does coal, so it could be used to smelt iron ores into iron, contributing to the Industrial Revolution. Steam engines were also invented during the eighteenth century, and most of them burned coal to produce steam. By the early nineteenth century, steam engines were used to propel trains and ships, rapidly expanding transportation networks within and among nations.

The United States has abundant coal deposits, and the eastern states began to mine the substance by the mid-eighteenth century to propel ships and trains. Electric generators run by coal-fired steam were developed in the late nineteenth century, and coal became the major fuel for generating electricity in the twentieth century. Thus, much of the coal used during the first half of the twentieth century was used for heating, rail transportation, and electricity. As petroleum and natural gas became more readily available in the late twentieth century, those substances became more common for heating and powering trains. Most coal use then became devoted to electrical generation. Lesser amounts of coal have also been used by other industries, for example to produce steel from iron ores.

Initially, coal was mined using hand tools such as picks to break it up and remove it from the surrounding earth, often in underground mines. The coal was then carried away in handcarts. Many coal beds are fairly flat-lying or are layers that can be followed laterally, but some beds may be less than a meter thick. This situation can result in underground mines that are only as thick as the coal beds themselves. Children, because of their small size and the low wages for which they would work, were often used in the nineteenth century to bring out the coal from such mines in many countries, such as England and the United States. Work hours were also long, with miners working as many as sixty hours per week. These hours were gradually reduced in the twentieth century, when heavier machines came to be used to more readily break up and transport the coal. The unionization of miners in the United States also led to shorter hours and better pay for those workers.

Underground jobs are dangerous, especially in the early years when miners breathed coal dust and silicate dust without protection, resulting in black lung disease and silicosis. The buildup of gases such as methane in some mines resulted in many catastrophic explosions. More than 120,000 miners in the United States alone have been killed by accidents in coal mines since 1870. Most of these deaths occurred in the early twentieth century, and the number of deaths has decreased drastically in contemporary mines as safety measures have been adopted.

The use of large machines to break up, extract, and move coal has brought about a significant reduction in the coal mining workforce in the United States, from around 700,000 persons in the 1920s to about 170,000 persons around the turn of the twenty-first century and then to less than 60,000 in the late 2010s. The number decreased again to 42,000 in 2020 and again to 36,659 in 2023.

The Industry Today

Coal is formed over millions of years from buried swamp plants such as those now found in the Florida Everglades. When such plants die, some of their remains can become preserved in the swamp water if its oxygen content is low enough. As the dead plants are gradually buried by sediment, their remains transform into peat, lignite, and subbituminous, bituminous, and anthracite coal—in that order—as they become buried more deeply and reach higher temperatures. During this process, the amount of volatiles such as water contained by the coal gradually decreases, and its carbon content gradually increases, so each type of coal burns hotter than its precursor. As coal develops, it forms horizontal beds that are associated with other sedimentary rocks, such as mudstones, sandstones (mostly composed of sand), and limestones (mostly composed of calcium carbonate). Coal beds' thickness ranges from a few centimeters to tens of meters or more. Even though the beds are originally horizontal, they may become folded or fractured, requiring some effort on the part of geologists to interpret their distribution.

Coal is widely distributed throughout the world. More than two-thirds of the world's coal reserves occur in China, Russia, and the United States. South Africa, Australia, Germany, Poland, and England also have major coal reserves.

Most coal in the eastern and central United States is either bituminous or anthracite, with high sulfur content, and some of this coal is extensively folded or faulted. Most coal in the northern Great Plains and the Rocky Mountain region is lignite or subbituminous, which is low in sulfur. Wyoming contains large amounts of thick, horizontal coal beds at or near the surface. Such deposits may be surface mined more economically than those in the eastern United States that require underground mines. The size, thickness, and shape of a coal deposit, as well as the kind of coal in the deposit, influence whether the deposit is mined by surface or underground mining.

In modern coal mining operations in the United States, surface mines have been more common underground mines (though both types saw drastic closures in the early twenty-first century). To engage in surface mining, miners must remove the overburden (non-coal sediment covering the coal), so the coal itself can be extracted with machinery and explosives. Often, the coal is taken in successive strips across the coalface, so the term "strip mining" is used to describe this process. For surface mining to be cost-effective, the overburden cannot be too thick.

Surface mining is usually more economical than underground mining because it is easier to break up and remove coal with large machines at the surface than it is to work with the smaller tools and machines that fit within tunnels. Also, surface mines have fewer air, electricity, and water problems than do underground mines. Underground mines are often smaller operations than surface mines, and they disturb much less land surface than do strip mines, unless they collapse during or after operations.

In underground mines, the coal is often broken into pieces with electric drills and cutters and then moved by conveyor to the surface, where it is loaded onto trucks or railroad cars. Some mines use machines with rotating cutters that move back and forth across coal beds, both breaking up and transporting pieces of coal. Enough pillars of coal must be left standing within a mine to support the layers of rock above it, so it does not collapse. Coal beds as thin as sixty centimeters usually can be mined economically.

The greatest hazards within underground mines include methane gas (which can collect locally and explode), falling rock, and mining machines themselves, which can be quite dangerous. Several other gases can cause problems if they build up sufficiently in a mine. Carbon dioxide can suffocate miners by displacing oxygen, and carbon monoxide can cause sickness or death. The well-ventilated underground mines of today often avoid problems with these gases, however.

Overburdens and the coal in surface mines are usually removed first by using explosives to break up the material and then by using large machines such as bulldozers, huge shovels, loaders, and draglines to move the fragments. Draglines are two-thousand- to thirteen-thousand-ton machines that can move up to 130 tons of material in their shovels at one time. If the overburden becomes too thick in a surface mine, the operation may proceed underground.

During the early twentieth century, most coal was mined underground, in part because there was no economical way to remove overburdens above even shallow coal beds. Moreover, the coal that was most easily accessible to surface mining was located in Wyoming, too far from the large energy markets in the eastern United States. In the twenty-first century, by contrast, the development of large-scale equipment has made it much more economical to mine near-surface coal with overburden thicknesses as great as thirty meters, and Wyoming's thick, low-sulfur coal beds are now close to many electrical generating plants. As a result, coal mining has shifted from east to west in the United States, with a greater use of the low-sulfur lignite and subbituminous coal in the Great Plains relative to the higher-sulfur bituminous and anthracite coals of the eastern United States. Wyoming's movement to larger surface coal mines has also greatly increased coal production per miner, and mines are safer than they once were, though major accidents do still occur.

A number of environmental problems result from coal mining that can be very costly for mining companies to solve. High-sulfur coals have iron sulfide minerals in them that react with water and the atmospheric oxygen within mines, producing sulfuric acid waters high in iron and some other dissolved elements. These acid waters can contaminate groundwater and streams and kill fish and other organisms, as has happened in Pennsylvania and West Virginia in the eastern United States. The dissolved iron also oxidizes at the surface and produces large amounts of unsightly iron compounds in contaminated streams.

Burning high-sulfur coal produces sulfur dioxide, which reacts with atmospheric water vapor to produce acid rain. Thus, laws have been passed capping the permissible amount of sulfur dioxide emissions from coal burning. These laws have increased the use of low-sulfur coal in electrical generating plants, since it is very expensive to capture or otherwise minimize the sulfur dioxide released by burning high-sulfur coal. Burning coal also gives off a lot of carbon dioxide, which has possibly contributed to global warming and the acidification of the oceans.

A number of other environmental problems are associated with the coal industry, such as the collapse or burning of coal in old, abandoned underground mines and the destruction of countryside caused by surface mining. Some mining operations in West Virginia have formed massive piles of fine-grained waste, much of which rapidly runs off into streams during major rainfalls. Modern mining operations are supposed to fix such problems, and the expense of doing so reduces their profit margins.

Industry Outlook

Overview

In the United States, the coal mining industry saw extensive consolidation through the late twentieth century, with the number of companies shrinking even as output increased. In the early twenty-first century, trends such as increasing use of natural gas, investment in alternative energy sources, and environmental regulation led to declining demand for coal and therefore reductions in production. By 2022 only 991 US coal mines were operational compared to 1,500 in 2008. This decline was largely expected to continue, although some volatility was expected as prices fluctuate in response to changing markets and technology, and industry revenues were forecast to eventually stabilize. Political trends also play a role, as some administrations—whether at the presidential, state, or local level—tend to support the coal industry while others push for cleaner energy sources. According to the US Energy Information Administration (EIA), the main use for coal remains electrical generation; lesser amounts are employed for industrial applications such as steel and cement production.

Globally, the coal mining industry was also expected to decline or hold relatively steady. The EIA reported in 2019 that China remained the world's top producer and consumer of coal, but projected that consumption would remain fairly stable after peaking in 2013. Potential decreases in coal consumption in China are partly due to contraction in industries that use coal, such as the steel industry. Coal consumption was also projected to continue to decline in countries of the Organisation for Economic Cooperation and Development (OECD) in the short term, before stabilizing through 2050. However, coal production was expected to increase over the long term in India and other Asian countries not belonging to the OECD.

Employment Advantages

A wide range of jobs is available in the coal industry, especially for those persons who enjoy working outside in surface mines or underground in subsurface mines. Those who like technical work, science, and mathematics can gain college degrees in mining engineering, geology, or environmental science. Those who like working or repairing machines, have high school diplomas, and enjoy working hard can obtain specialized training, often at mine sites, to become equipment operators, truck drivers, or repair personnel. Those who like to work in office buildings can seek work as secretaries, computer specialists, accountants, or general office workers. These jobs likely will require some advanced training beyond high school. Other office jobs include administrators and managers, but these positions require significant work experience in mining and often college degrees in business or engineering.

Annual Earnings

Coal mining, like other types of mining and the petroleum industry, experiences fluctuations in production, and therefore in earnings, in response to issues of supply and demand. Yet even with volatility and overall decline, the industry remains a significant economic contributor. The market research firm IBISWorld estimated that the US coal mining industry saw $27.6 billion in revenues in 2024, while the global industry took in $2.5 trillion. While this represented steady decrease over the previous five years, analysts projected that earnings would eventually stabilize.

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