There are three general categories of coal reserves. Each category is an estimate of available coal, based on distinctive criteria. (Note: The definition of a short ton is 2000 pounds.)

• Demonstrated Reserve Base (DRB) is the estimated amount of coal that could be mined at a particular time. It includes both measured and indicated resource categories of reliability. It is estimated that there are about 476 billion short tons of DRB available.
• Estimated Recoverable Reserves includes only coal that could be mined with current technology after taking into account coal accessibility and recovery potential. There are approximately 254 billion short tons available in this category.
• Recoverable reserves at producing mines are the known reserves from active mines that are reported by mining companies to the federal government. These reserves are estimated at 17 billion short tons.

The above image shows the history of U.S. imports and exports of coal during the time 1950 - 2017. The U.S. is a net exporter of coal, and in 2017 the top countries that received exported coal from the U.S. were:

• India = 11.8%
• South Korea - 9.7%
• The Netherlands - 9.7%
• Japan - 7.9%
• Brazil - 7.8%

(Percentage values indicate proportions of total U.S. coal exports received by each country.)