Coal is located in seams within the earth and is brought to the surface by a process known as mining. According to the U.S. Energy Information Administration (EIA), there are around 257 billion recoverable short tons of coal in the U.S. as of 2014.
The actual demonstrated reserve base (DRB) of coal in the U.S. is 481 billion short tons. However, not all coal in the U.S. is recoverable, largely due to limited access that occurs because of land use conflicts, property rights issues and environmental and physical restrictions. For example, in some underground coal mines, some of the coal in the mine is left undisturbed to keep the mine from collapsing. Physical features, like inter-layered rock strata, may also make mining some veins of coal impossible.