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North Dakota: Legendary. Follow the trail of legends

What is Coal?

What coal is:

Pile of Coal
Types of Coal: There are four different types of coal: anthracite, bituminous, subbituminous and lignite.
  • Coal is a nonrenewable source of energy.
  • Coal is a solid fossil fuel created from vegetation that was squeezed by pressure for millions of years.
    • During the first part of the Cenozoic Era, which began about 65 million years ago, the last of the seas that had covered North Dakota drained away.
      • Layer after layer of rotted trees and other vegetation piled up in swamps over millions of years.
      • Pressure from the heavy weight and heat from the earth turned these mats of vegetation into a solid black or dark brown rock called coal.


The three fossil fuelscoal, petroleum, and natural gas were formed in a similar way by heat and pressure, but petroleum and natural gas were formed from plants and animals that lived in oceans and are millions of years older than coal. This caused them to become a liquid (petroleum) or a gas (natural gas).



  • The kind of coal that was formed in North Dakota is called lignite.
    • Lignite is a very soft coal because it is younger than the harder coals (anthracite, bituminous and subbituminous) found in other parts of the United States. Harder coals are found deeper underground than lignite and are mined differently from the way lignite is mined.