Montana has 24 percent of the nation’s coal reserves
Coal is both abundant and relatively inexpensive in the US, so it is an appealing source of electricity generation for both economic and energy-security reasons. On the flip side, carbon dioxide generated by the burning of fossil fuels is the primary cause of global warming, and burning coal generates the lion's share. Technology for capturing and storing CO2 from coal-fired power plants is under development to try to address this problem.
Montana has a significant piece of the abundant US coal resource. According to the US Energy Information Administration, Montana’s coal reserves (the technical term is “demonstrated reserve base,” or DRB) totaled 119 billion tons as of January, 1, 2008, which amounts to 24% of the total estimated DRB for the US[[Energy Information Administration. “Table 4.11 Coal Demonstrated Reserve Base, January 1, 2008 (Billion Short Tons).”]]
Some of this coal is unlikely to be mined because it is too costly, too technically difficult or too environmentally damaging to retrieve.