Coal is a combustible mineral that serves as the primary fuel source for the generation of electric power and as a vital ingredient in the production of steel. According to the World Coal Institute, or WCI, coal fuels approximately 41% of global electricity generation, and approximately 68% of global steel production utilizes coal in the manufacturing process. In general, coal of all geological composition is characterized by end use as either steam coal, also known as thermal coal, or metallurgical coal. Nearly half of the United States’ electricity is produced by burning steam coal. Metallurgical coal is heated to produce coke, which is used in smelting iron ore to make steel.

Coal is the most abundant fossil fuel in the United States, representing the vast majority of the nation’s total fossil fuel reserves. The United States has the largest proved reserves of coal in the world, with approximately 263 billion tons. The United States is the second largest producer of coal after China. At current rates of production, the United States has approximately 245 years of coal supply remaining.

Key attributes in grading metallurgical coal are its sulfur, ash and moisture content and coking characteristics, as compared to the key attributes in grading steam coal, which are heat value, ash and sulfur content. Metallurgical coal used to make coke must be low in sulfur and requires more thorough cleaning than coal used in power plants, and therefore it commands a higher price per ton than steam coal.