Through the centuries, prehistoric seas alternately advanced and receded, depositing layers of sediment on peat (decayed organic matter or vegetation). The sediment accumulated and the earth’s crust shifted, compressing the peat, squeezing out its moisture and burying it deeper and deeper.
Heat generated by the tremendous pressure on the buried beds drew out most of the oxygen and hydrogen, leaving a residue of impure carbon – coal. Missouri was the first state west of the Mississippi River to produce coal commercially. Coal mining in Missouri is conducted entirely by surface mining methods but was mined historically by underground methods, as well. Missouri coal is bituminous, but some cannel coal also is present. Bituminous coal occurs in horizontal beds or seams in the northern and western parts of the state and breaks with a blocky fracture. It is commonly layered and often contains impurities such as calcite, gypsum, pyrite, marcasite, clay minerals and quartz.
Cannel coal is found chiefly in old sinkhole deposits in central Missouri. It is composed almost entirely of plant spores, fractures conchoidally and has a more massive structure than bituminous coal. Cannel coal burns to a very hot, rather quick fire because of the nature of its highly volatile content.
The principal value of coal is in the amount of heat it can generate, a factor directly related to its stage of development. Heat value is measured in British Thermal Units, or Btu. One Btu is the energy necessary to raise the temperature of one pound (one pint) of water one degree Fahrenheit. Heat values of Missouri coal on an as-received basis average 11,016 Btu per pound.
Coal continues to be a primary source of energy throughout the world. Missouri produced 9.1 trillion Btu of coal in 2013. Missouri’s coal is burned at power plants to generate electricity and at limestone kilns to produce cement. According to the U.S. Energy Information Administration’s coal consumption estimates, 806.5 trillion Btu of coal were consumed in Missouri in 2013. Natural gas used 281.5 trillion Btu.
The department makes sure mined land is returned to the best possible condition for use after mining is completed. Team members with the department’s Land Reclamation Program work to guarantee Missouri’s mineral resources are available for economic development, and after reclamation, the land is available for new development or public use.
The Abandoned Mine Lands Viewer identifies locations of reclaimed coal mining activities.
Coal samples are on display in our Ed Clark Museum of Missouri Geology.