Sub bituminous coal has a higher heating value than lignite. Sub bituminous coal typically contains 35-45 percent carbon, compared to 25-35 percent for lignite. Most sub bituminous coal in the U. S. is at least 100 million years old. About 42 percent of the coal produced in the United States is sub bituminous. Wyoming is the leading source of sub bituminous coal.
Sub bituminous coal has a higher heating value than lignite. Sub bituminous coal typically contains