Subbituminous and bituminous coal dominate U.S. coal ...
Jun 04, 2020· Subbituminous coal typically contains 35%–45% carbon, and it has a lower heating value than bituminous coal. Most subbituminous coal in the United States is at least 100 million years old. About 45% of total U.S. coal production in 2018 was subbituminous and nearly 89% was produced in Wyoming. Lignite contains 25%–35% carbon and has the ...