Kids, there are many things that we use every day that are mined from the ground. Things you may never think of such as portland cement which is used to make concrete, or sulfur, or salt, are mined. Illinois mines provide primarily crushed stone, portland cement, sand, gravel, and coal. The website www.msha.gov/kids/mining.htm will let you click on any state to see what is mined there. Coal is our most abundant fossil fuel resource. It is a complex mixture of organic chemical substances containing carbon, hydrogen, and oxygen, with small amounts of nitrogen and sulfur. The degree of coalification, also called the rank of coal, increases from lignite (brown coal) to low rank coal (sub-bituminous), to high rank coal (bituminous), to anthracite. Carbon goes up and oxygen and hydrogen go down along the series. The hardness increases and the reactivity decreases. Different heats and pressures during geochemical development cause these differences in rank. It is not due to the kind of plants the coal is formed from.

Please note:  All chemicals and experiments can entail an element of risk, and no experiments should be performed without proper adult supervision.

U.S. coals range from lignite with 30% carbon and a heating value of 7,000 Btu per pound to anthracite with 85% carbon and a heating value of 12,750 Btu per pound. Sub-bituminous and bituminous coals are between these values. There are two methods of mining coal, surface mining and underground mining. There are over 1,000 mines of each type in the U.S. Underground mining is more difficult and requires more miners, but much of our best coal is underground. Lately, surface mining in Wyoming has made it the top coal producer at almost 300,000 tons per year. West Virginia and Kentucky, the traditional leaders, each produce around 170,000 tons. Last year about 1 billions tons of coal was mined in the U.S. with almost 60% used by electric utility companies. Coal is also used to make plastic and steel. When used as a fuel, coal can be burned just as it comes from the ground or converted into fuel liquids.

Here is your activity. Get a chocolate chip cookie, a chocolate chunk cookie, an oatmeal raisin cookie, and two toothpicks. Think about how these cookies represent mining the 3 major types of coal. The raisins represent the soft coal lignite, the chocolate chips are the hardest coal anthracite, and the slightly softer chocolate chunks are most like bituminous coal. All of them are embedded in cookie dough "rock". Using your toothpicks as jackhammers and picks, separate the coal from the rock. Make neat piles of chips, chunks, raisins, and cookie crumbs. Now put the cookie crumbs back together. How, and why, you say? Reclamation is an important part of the mining process in order to be good stewards of the land. Some stone quarries that are now recreation areas are Centennial Beach in Naperville and Quarry Beach in Batavia. (By the way, don't forget to eat the fruits of your labor!).

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Kathleen Carrado Gregar, PhD, Argonne National Labs 
[email protected]
October 2002

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Reference: www.osmre.gov, and J. Licandro (Scullen Middle School, Naperville) from 8/4/02 "School Rocks" article in the Naperville Sun by D. DeFalco.