It estimates that 25 billion tons of those resources are currently economical to recover.
“It’s important to note … the substantial difference between what is in place and what is technically recoverable, let alone economic,” USGS acting director Suzette Kimball said.
“This new basin-wide assessment provides that critical link for government and private managers to make informed decisions.”
The Powder River Basin covers a large portion of land in northeastern Wyoming and southeastern Montana.
The basin contains the largest deposits of low-sulfur sub-bituminous coal in the world, typically used in electric power generation.
The USGS said this study was significant because it illustrated that only a relatively small percentage of in-place coal resources were technically and economically recoverable.
In 2011, the 16 mines in the Powder River Basin produced 462 million tons of coal, about 42% of the nation’s total coal production that year.
Cloud Peak Energy, Alpha Natural Resources, Arch Coal, Peabody Energy and Westmoreland Coal are among the companies operating in the Powder River Basin.