Coal mining

• 1. Introduction

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  Coal mining is one of the oldest industrial pursuits in human history, and it has shaped nations, landscapes, and the air people breathe across every inhabited continent. In the United States alone, 104,895 coal miners have been killed in mine accidents since 1900. That number sits at the center of every honest account of what coal extraction has meant for the people who do it. In the worst single year on record, 3,242 miners died in 1907. By 2020, that annual toll had fallen to five. What happened in between is a story of technology, economics, politics, and survival. How do you pull hundreds of millions of tons of rock and fuel from the earth each year? What does it cost the land, the water, and the bodies of the workers? And as the world's energy economy shifts, what becomes of the communities that built their lives around the mine?

• 2. Digging into the Earth

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  Surface mining and deep underground mining are the two fundamental approaches to getting coal out of the ground, and the choice between them depends on how far down the coal seam lies. Seams within roughly 200 feet of the surface are typically handled from above; those at depths of 300 feet or more almost always require underground work. At the extreme end, some open pit operations in Germany reach more than 1,000 feet below ground level. Tagebau Hambach in Germany is one such operation, pushing the conventional limits of surface extraction.

  Strip mining removes the earth above a coal seam in long parallel cuts. The first strip's overburden goes to a dump outside the mining area; each subsequent cut's waste fills the void left by the one before it. Where terrain is flat, this method can sustain a mine for more than 50 years. Contour mining adapts the same basic logic to rolling hills and steep ridges, following the shape of the land and sometimes leaving a ridge of undisturbed material 15 to 20 feet wide at the outer edge to stabilize the reclaimed slope.

  Mountaintop removal is the most controversial variation. The entire top of a ridge is removed in a series of parallel cuts, and the overburden is deposited into adjacent valleys. These valley fills cover streams and reshape ecosystems in ways the land does not recover from quickly. Globally, about 40 percent of coal production comes from surface methods; in Australia, the figure is around 80 percent.

• 3. Underground

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  About 60 percent of world coal production currently comes from underground mines, where the basic challenge is to extract coal without bringing the roof down on the people doing the work. In the room and pillar method, miners cut a network of rooms through the seam, leaving pillars of coal standing to support the ceiling. Those pillars can account for up to 40 percent of the coal in a seam, but historical evidence from 18th-century operations uncovered by later open cast excavations shows that earlier miners sometimes managed to recover 92 percent of the coal in place using variants of this method.

  Longwall mining represents the dominant modern approach, accounting for about 50 percent of underground production. A longwall shearer has a working face of 1,000 feet or more. Its rotating drum moves back and forth across the seam, and the loosened coal drops onto an armored chain conveyor that carries it away. Hydraulic roof supports advance with the machine as it moves forward; behind the machine, the roof is allowed to fall in a controlled way. When conditions allow, longwall systems recover 60 to 100 percent of the coal in a section.

  Continuous mining machines use a rotating steel drum fitted with tungsten carbide picks. Operating in the room and pillar system, a continuous miner can extract as much as 14 tons of coal per minute, more than an entire non-mechanized mine of the 1920s would produce in a full day. Continuous miners account for about 45 percent of underground coal production. Blast mining, the older practice of using explosives like dynamite to fracture the seam before loading, now accounts for less than 5 percent of underground production in the United States.

• 4. Hazards and Damps

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  Ninety percent of all U.S. coal mining fatalities since 1900 occurred in the first half of the 20th century, which tells you something about how dangerous the work once was. Underground mining hazards include suffocation, gas poisoning, roof collapse, rock burst, and gas explosions. Of those, the gas hazards have their own taxonomy, rooted in a German word: Dampf, meaning steam or vapor.

  Fire damp is mostly methane. It explodes when concentrations reach 5 to 15 percent, and causes asphyxiation at 25 percent. A fire damp explosion can trigger a far more dangerous coal dust explosion capable of engulfing an entire mine. Black damp is a mixture of carbon dioxide and nitrogen that forms through corrosion in enclosed spaces and causes suffocation by displacing oxygen. After damp, which forms following a mine explosion, contains carbon monoxide, carbon dioxide, and nitrogen. White damp is air carrying carbon monoxide, which is toxic even at low concentrations. Stink damp, named for the rotten egg odor of hydrogen sulfide, can both explode and poison.

  A heavy curtain used to direct air currents and prevent gas buildup is known as a damp sheet. The use of small animals, famously canaries, to detect dangerous gas concentrations has been replaced by sophisticated electronic sensing equipment. Statistical analysis by the U.S. Mine Safety and Health Administration showed that between 1990 and 2004, the industry cut its injury rate by more than half and its fatality rate by two-thirds. Even so, the Bureau of Labor Statistics ranked mining as the second most dangerous occupation in the country as recently as 2006. The Sago Mine disaster of 2006 and the 2010 Upper Big Branch Mine disaster in West Virginia, which killed 29 miners, showed that multiple-fatality events had not disappeared.

• 5. Chronic Toll on Workers

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  Pneumoconiosis, known as black lung, was once common enough among miners that it measurably shortened life expectancy across the industry. In the United States, 4,000 new cases of black lung are diagnosed every year, a rate that works out to about 4 percent of workers annually. In China, the figure is 10,000 new cases per year, though that represents only 0.2 percent of a much larger workforce. Water sprays on mining equipment reduce the concentration of airborne coal dust and lower the risk to miners' lungs.

  Noise is a less visible but persistent hazard. Dragline equipment at surface mines has been measured at 88 to 112 dBA. Within longwall sections, stageloaders and shearers generate some of the highest exposures. Auxiliary fans can reach 120 dBA; continuous mining machines up to 109 dBA; roof bolters up to 103 dBA. The U.S. Mine Safety and Health Administration sets a permissible exposure limit of 90 dBA over an eight-hour day. Exposures above that threshold lead to noise-induced hearing loss, which the field calls occupational hearing loss.

  Increased surface coal mining activity has also been linked to higher rates of cardiovascular disease mortality among workers and nearby populations. Exposure to coal mining environments has been shown to affect immune function, renal health, and blood cells. One study suggested that modern mining hazards are increasingly long-term in character, with conditions like sleep deprivation accumulating across a career rather than presenting as single acute events. In 2015, U.S. coal mines employed 65,971 workers, the lowest count since the Energy Information Administration began collecting data in 1978.

• 6. Who Mines the World's Coal

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  Coal is mined commercially in more than 50 countries. In 2019, total global production reached 7,921 million metric tons, a 70 percent increase over the preceding 20 years. China leads all producers by a large margin, with an estimated 3,692 million metric tons in 2019. India, the United States, Indonesia, and Australia follow in that order. The top ten producers together include Russia, South Africa, Germany, Kazakhstan, and Poland.

  Production has grown fastest in Asia while declining in Europe. In the United Kingdom, underground coal mining in Germany ended when RAG AG, the owner of the two remaining mines, Prosper Haniel and Ibbenbüren, closed both facilities in 2018 following a Bundestag decision in 2007 to end subsidies under EU regulations. Open pit lignite mining for electricity continues in Germany's Nordrhein-Westfalen and in the eastern states.

  Some national mining histories carry unusual detail. The first coal mines in North America were at Joggins and Port Morien in Nova Scotia, worked by French settlers beginning in the late 1600s. The coal supplied the British garrison at Annapolis Royal and went into the construction of the Fortress of Louisbourg. In Japan, it is said that coal was first discovered in 1469 by a farming couple near Omuta in central Kyushu. Argentina's Rio Turbio coal mines began producing around 1943, after the government of Roberto Ortiz created the state company Yacimientos Carboníferos Fiscales in 1941 in response to wartime supply threats.

  Colombia's Cerrejón mine in 2004 produced 24.9 million tons from one of the world's largest open pit operations. It has its own 150-kilometer standard-gauge railroad connecting the mine to Puerto Bolivar on the Caribbean coast, with two 120-car unit trains each carrying 12,000 tons per trip and a round-trip time of about 12 hours.

• 7. Environmental Costs and the Energy Shift

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  Coal mining causes land degradation, polluted waterways, and acid mine drainage. Studies link large-scale coal extraction to declining environmental quality across most affected land areas. Chinese underground mines frequently produce severe surface subsidence of 6 to 12 meters, damaging farmland drainage and leaving land unsuitable for agriculture. China does not require extensive reclamation, and the resulting abandoned acreage is inhospitable to indigenous wildlife. Because most Chinese coal is burned domestically with little air pollution control equipment, it contributes heavily to visible smoke and severe air pollution in industrial areas.

  For these reasons, coal has been among the first fossil fuels to be phased out of parts of the global energy economy. In several regions, producers have already reached peak coal as economies shift toward alternatives. A 2020 study found that renewable energy jobs could feasibly be created in most affected geographies to replace coal mining employment as part of a managed transition. However, the study also found that renewable energy was not suitable in some regions with high concentrations of miners, specifically naming China.

  A 2016 study in the United States found that retraining coal workers for the solar photovoltaic industry was technically possible and would cost roughly 5 percent of a single year's industrial revenue to provide job security across the affected workforce. The Harvard Business Review addressed the same question as solar employment in the U.S. rose rapidly. On the 13th of April 2016, Peabody Energy filed for Chapter 11 bankruptcy after reporting a 17 percent revenue decline and a two-billion-dollar loss the previous year. A court in Australia has cited climate change in ruling against a proposed new coal mine, a development that signals how legal and regulatory terrain around the industry continues to change.