2021-12-9 · Background. Caballo Mine is a surface coal mining operation in Campbell County, Wyoming, owned by Peabody Energy.The mine opened in 1978. It produced 11.3 million tons of coal in 2018, and has 465 million tons of reserves.Annual Coal Reports - U.S. Energy Information ...The Annual Coal Report (ACR) provides annual data on U.S. coal production, number of mines, productive capacity, recoverable reserves, employment, productivity, consumption, stocks, and prices. All data for 2020 and previous years are final. Highlights for 2020. U.S. coal production decreased 24.2% year over year to 535.4 million short tons (MMst).