Once the coal has been mined it needs to be processed.
1. The coal first goes to a preparation plant, where it is washed or cleaned to remove contaminants. The cleaning removes impurities like rocks, ash, sulfur, and other substances.
Coal that is going to be burned in solid form may go through a variety of preparation processes. The simplest of these is removing foreign material and screening for size.
2. Large pieces may be crushed or pulverized to a useful size, because mined coal may have lumps up to 3 feet or so in size, this is usually a two-stage process. First the coal is crushed in a feeder breaker, which breaks the biggest lumps, and then through a roll crusher, which breaks it down to a smaller size.
3. After the coal has been processed, it is then cleaned and transported by trucks, trains, and river barges to markets. Some coal is crushed and mixed with water and transported through pipelines.