There are four major coal classifications: anthracite, bituminous, sub bituminous and lignite. Indiana coal is bituminous.
Coal is generally characterized and priced based upon its different characteristics. Some of the most common are:
BTUs is a measurement of how hot coal burns. Indiana coal provides good heat value; 10,500-12,000 BTUs/lb.
Moisture Content isthe amount of water reduces the fuel or burning power, and can generate excess steam. Indiana is known for low levels of moisture ranging from 6-15 percent.
Ash is material remaining after coal is burned. These are impurities which must be collected and disposed of. Indiana coal ash content is considered moderate to low at 7 to 13 percent by weight.
Sulphur is an impurity which is removed by processing on-site and when burned at a utility. Sulphur content of Indiana coal varies widely. Some coals are very low (0.5 percent) in sulphur and considered a compliance grade. Others are generally thought of as a "high-sulfur" coal with 2-6 percent by weight.