Why is Coal Important?


There is probably not a single person in the United States that is not dependent to some extent on coal. Coal is at work each time you turn on a switch that allows electricity to power up your lights, microwave, stereo, TV, computer and all those other electircal appliances and gadgets you have lying around the house.

And where does the rest of our electricity come from?

How Coal Is Formed

COAL is a fossil fuel. It is derived from plant material that was buried millions of years ago in a four step process:

  1. Lush vegetation grew in warm swampy areas that covered much of the United States (and the world) about 300 million years ago. The plants and trees absorbed the rays of the sun - used in photosynthesis - which was stored in the leaves and tissues.

  2. As the vegetation died, it fell into the swamps. As the amount of material accumulated in the presence of the water, it began to form a spongy, brown material which we know as peat or peat moss.

  3. Over time, geologic forces buried the peat bogs - sometimes hundreds of feet deep - where they were compacted by the pressure of the soil and rock on top of them.

  4. Coal was gradually formed from the buried peat. The greater the pressure under which the coal was formed, the harder the coal that was produced.

Types of Coal

There are four major types of coal. From the softest to the hardest they are:

This illustration shows the profile (or cross-section) of a coal mine. Note the overburden.
(Courtesy of Black Hills Corp. Wyodak Mine)

Where Is It Found

(Information courtesy of the USGS)

Coal Production in the United States

Coal is mined in 32 states. The three major U.S. coal producing regions are Appalachia (West Virginia, Pennsylvania, Virginia, Eastern Kentucky, and Ohio), the Illinois Basin (Illinois, Indiana and Western Kentucky) and the Powder River Basin (Wyoming and Montana). Lignite coal is produced primarily in western North Dakota and in eastern Montana.

The way the layers or seams of coal occur and the has much to do with how it is mined and its ultimate cost to consumers. For example, in Illinois Basin mines, 50 feet of overburden must often be removed to reach a 5-10 foot seam of coal. At the other end of the spectrum, in the Powder River Basin, you may only have to remove 5 feet of overburden to get to a 50 foot thick seam - substantially lowering the cost of mining.

The seams of coal are clearly visible in this photo taken at a Colorado mine.
(Courtesy of Kenncott Colowyo Mine)

Since acid rain is such an important environmental issue, the sulfur content of coal is VERY important. A major cause of acid rain is said to be sulfur dioxide emissions. When sulfur dioxide is mixed with water, a chemical reaction takes place and sulfuric acid is formed. Government regulations set the emission standards that must be met by every company that burns coal.

Ironically, one of the ways to reduce those emissions (and thus reduce acid rain) is for power plants to install scrubbers on their stacks. Another mineral - limestone - is used in the scrubbers to help remove the sulfur before it finds its way into the atmosphere.

Nearly 950 million tons of coal are produced annually in the United States. The top ten coal producing states by rank and tonnage produced are:

3.West Virginia135,439,000
9.North Dakota32,851,000
All Other States<155,000,000
Total U.S.946,732,000
(Table courtesy of the Wyoming Mining Association.)

If we continue mining coal at current rates, the US has between 500 and 1,000 years of coal reserves remaining. Put another way, it means that, at a minimum, and IF we choose to do so, we have enough coal reserves to produce electricity at current consumption rates for a period equal to that time between the time Columbus first set foot in the New World and today.

The following table shows the ten states with the largest reserves of coal. It also shows the total figure for all the reserves in the remaining 40 states.

RankStateUnderground ReserveSurface ReserveTotal Reserve% of Total U.S.
4.West Virginia33.
All Other States24.625.150.110.9
Total U.S.320.9153.6474.5100.0
(Table courtesy of the Wyoming Mining Association.)

Coal Mining

The days of mining coal with picks, shovels and pit ponies are gone forever. Todays miner is a different breed. His pick and shovel have been replaced by instrument panels on huge trucks, front-end loaders and draglines or by a computer console.

This picture shows a dragline at work at the far end of the mine. To put the size of the
equipment in perspective, the tires on the loader in the foreground are taller than a man!
(Courtesy of Peabody Lee Ranch Mine)

The mines where this equipment is used do not look much like the images of old, either. In today's underground mine, the walls are white, covered with a coating of lime that prevents coal dust. Constant fresh air flows steadily through the mine, moved by huge ventilation fans on the surface. Personal protective equipment including hard-hats, steel-toed boots, hearing protection, air purifying systems and high intensity lamps are standard issue for the modern miner.

Mining is a temporary use of the land. When mining of an area has been completed, the mining company is required by federal and state law to return the land and water to as good, or better, condition as before mining. Since 1974, more than two million acres of land - an area larger than the state of Delaware - have been reclaimed for other uses ranging from recreation to housing development.

The next time you flip a switch to get that electrical power you need, remember that there are miles and miles of wires and lines that connect your home to a power plant you may never see. And chances are, at least 56% of the time, that power plant will be burning coal. To see how all that electricity is produced, take the online tour of a coal-fired power plant at the Lignite Energy Councils website.

If you still need additional information about coal, the best site I know of is the Virtual Coal Library compiled by the Australians. It is well organized, easy to navigate and contains worldwide information and links.