In widespread use since the Industrial Revolution, coal still represents a sizable fraction of global energy consumption. At every stage in coal’s life cycle -- from mining to burning -- it also represents a significant threat to the health of people and the environment.

How is coal extracted?

The method used to extract coal depends primarily on the depth of the deposit. If the coal seam is at or near the surface, there are two techniques:

1. Strip mining exposes the coal by the advancement of an open pit or strip.  As the coal is exposed and extracted, the earth overlying still-covered coal fills the former pit, and the strip progresses.  
2. Utilized for the past 30 years, mountaintop removal involves removing the highest part of the mountain for the maximum recovery of coal. It is a commonly applied technique in Appalachia.

Most coal seams are too deep below the surface, and instead require one of several underground mining techniques. Many coals extracted from both surface and underground mines require washing in a coal preparation plant.

Where is coal found?

Nearly every country in the world has some coal reserves, with about 70 nations possessing sufficient quantities to make recovery feasible. Currently, China is the leading producer of coal, with the United States second and India third.

Why is coal dirty?

The impacts of burning coal for power -- including acid rain and large climate-altering carbon dioxide emissions -- are significant and widespread in themselves, and extracting the coal in the first place is similarly damaging. Coal mining harms land, surface waters, groundwater, and even our air. Surface mining causes drastic changes to the landscape, destroying habitats and completely removing land from its normal uses. Mining and processing of coal also stirs up massive quantities of dust and other pollutants, degrading air quality.

Coal mining generates huge quantities of waste -- tens of millions of tons each year in the U.S. alone. Piles of mining waste, prone to erosion, are sources of runoff that both pollutes and alters the flow of nearby streams. Acid mine drainage is a particularly severe byproduct, especially where coal seams have abundant quantities of pyrite. When pyrite is exposed to water and air, it forms sulfuric acid and iron, which are directly toxic to aquatic life and render the water unfit for use. Acid mine drainage can also seep into groundwater, made worse at times by physical disruption of aquifers from blasting.

In addition to destroying landscapes and polluting air and water, coal mining can pose a further risk to local communities. Mine waste products have been used to construct dams around disposal lagoons for liquefied coal wastes. In 1971, the collapse of such a dam in Buffalo Creek, WV, caused flooding that claimed 125 lives and resulted in millions of dollars in property damage.  A similar accident in 2000 occurred in Martin County, Kentucky, releasing 250 million gallons of coal waste into the Big Sandy River and its tributaries. More than 75 miles of the river were choked with lava-like sludge that killed all river life.

For More Information

• Northern Plains Resource Council:

  Montana based environmental advocacy group tells the truth about the legacy of strip mining in Montana.

• Appalachian Voices:

  Appalachian environmental advocacy group discusses the enormous impact mountaintop removal has had in the region.

• Environmental Literacy Council:

  A description of the multiple methods of coal mining and the benefits and dangers associated with them by a science based environmental advocacy group.

• Elmhurst College:

  College chemistry department discusses the facts, dangers, and solutions to acid rain produced by the coal industry.

• U.S. Department of Labor:

  U.S. Department of Labor's discussions include waste dam failures and U.S. government regulations of the coal industry.

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